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QUALITY ASSURANCE PROJECT PLAN for the Virginia River Input

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5. 0 04 4 4 1 4 6 3 2 Example of cell constants for contacting type sensors with electrodes and corresponding conductivity ranges 5 6 3 3 Correction factors for converting non temperature compensated values to conductivity at 25 degrees Celsius based on 1 000 microsiemens potassium chloride solution 0 0 0 10 6 3 4 Troubleshooting guide for conductivity esee eee ene eee 20 Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 3 SPECIFIC ELECTRICAL 6 3 CONDUCTANCE By D B Radtke J V Davis and F D Wilde Electrical conductance is a measure of the capacity of water or other media to conduct an electrical current Electrical conductance of water is a function of the types and quantities of dissolved substances in water but there is no universal linear relation between total dis solved substances and conductivity The USGS reports conductivity in microsiemens per centimeter at 25 degrees Celsius uS cm at 25 C The method described in this section for measuring conductivity is applicable to surface water and ground water from fresh to saline SPECIFIC ELECTRICAL CONDUCTANCE CONDUCTIVITY a measure of the electrical conductance of a substance normalized to unit length and unit cross section at a specified temperature EQUIPMENT AND SUPPLI
6. gz ur due TS6 0 vS6 O LS6 0 719670 9670 L496 0 04670 EL6 0 9L6 0 646 0 58670 48670 88670 16670 6670 L66 0 0007 0746 TS6 0 4670 14670 09670 lt 9670 79670 04670 L46 0 9 670 6 60 08670 48670 88670 716670 6670 26670 0007 O vE TS6 0 4670 LS6 0 09670 96 0 99670 69670 EL6 0 9 6 0 646 0 08670 68670 88670 16670 6670 6670 0007 0 08670 4670 14670 09670 lt 9670 99670 69670 4670 4 670 6L6 0 8670 48670 88670 66 0 6670 56670 0007 0 04670 4670 94670 64670 lt 9670 99670 69670 ZL6 0 SL6 0 8 670 86 0 986 0 886 0 66 0 6670 L66 0 000 05670 4670 94670 64670 29670 99670 69670 ZL6 0 SL6 0 8 670 I86 0 48670 88670 6670 6670 L66 0 0007 0706 00091 00057 000 OO0ET 00027 000 0000 0006 0008 0004 0009 0004 0007 000 0002 000 0 Do sz ur penunuo5 iAn npuoo uo peseq Panjossip 10 50322 UODO 77 279 Dissolved Oxygen Version 2 1 6 2006 Chapter A6 Field Measurements 46 DO SELECTED REFERENCES American Public Health Association 2005 Standard methods for the examination of water and wastewater 21st ed Washington D C American Public Health Association American Water Works Association and Water En
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9. Modify this list to meet specific needs of the field effort Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 5 Temperature measuring instruments for field and laboratory calibra tion use can be either a liquid in glass or thermistor thermometer Field personnel should be familiar with the instructions for use of the thermometer that are provided by the manufacturer Liquid in glass field thermometer Total immersion thermometers that are filled with a stable liquid such as alcohol are recommended for water measurements in the field Partial immersion thermometers are not recommended these have a ring or other mark to indicate the required immersion depth Thermometers for field use must not be mercury filled Before making temperature measurements check the type of liquid filled thermometer being used Thermistor thermometer A thermistor thermometer is an electrical device made of a solid semiconductor with a large temperature coefficient of resistivity An electrical signal processor meter converts changes in resistance to a readout calibrated in temperature units Thermistors are incorporated into digital thermometers individual parameter instruments such as conductivity and pH meters and multiparameter instruments used for surface water and ground water measurements CAUTION Do not use mercury filled thermometers in the field MAINTENANCE CLEANING AND STORAGE
10. 00020 HYDROXIDE 71834 mg L Dis OXYGEN 00300 mg L TEMP WATER 00010 col 100mL BAROMETRIC PRES 00025 mmHg TURBIDITY 61028 FECAL COLIFORM 31625 col 100mL DO Sar 00301 ALKALINITY TOTAL COLIFORM 31501 col 100 mL eH 00090 ANC OTHER pH 00400 BICARBONATE 00453 OTHER SAMPLING INFORMATION Sampler Type 84164 Sampler ID Sample Compositor Splitter PLASTIC TEFLON CHURN CONE OTHER Sampler Bottle Bag Material PLASTIC TEFLON OTHER Nozzle Material PLASTIC TEFLON OTHER Nozzle Size 3 16 1 4 5 16 Stream Width ft mi Left Bank Right Bank Mean Depth ft Ice Cover Ave Ice Thickness in Sampling Points Sampling Location WADING CABLEWAY BOAT BRIDGE UPSTREAM DOWNSTREAM SIDE OF BRIDGE ft mi above below gage Sampling Site POOL RIFFLE OPEN CHANNEL BRAIDED BACKWATER Bottom BEDROCK ROCK COBBLE GRAVEL SAND SILT CONCRETE OTHER Stream Color BROWN GREEN BLUE GRAY CLEAR OTHER Stream Mixing WELL MIXED STRATIFIED POORLY MIXED UNKNOWN OTHER Weather SKY CLEAR PARTLY CLOUDY CLOUDY PRECIP LIGHT MEDIUM HEAVY SNOW RAIN MIST WIND CALM LIGHT BREEZE GUSTY WINDY EST WIND SPEED__ TEMP VERY COLD WARM HOT COMMENTS Sampling Method 82398 Ew 10 EDI 20 SINGLE VERTICAL 30 MULT VERTICAL 40 OTHER Stage STABLE NORMAL STABLE HIGH RISING FALLING PEAK OBSERVATIONS COMPILED BY CHECKED BY DATE STN NO METER CALIBRATIONS TEMP
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12. Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 12 SC Conductivity must be measured at the field site Document the precision of your measurements Precision should be determined about every tenth sample or more frequently depending on study objectives Successive measurements should be repeated until they agree within 5 percent at conductivity lt 100 uS cm or within 3 percent at conductivity gt 100 uS cm The conductivity measurement reported must account for sample temperature If using an instrument that does not automatically tem perature compensate to 25 C record the uncompensated measurement in your field notes along with the corrected conductivity value Use correction factors supplied by the instrument manufacturer if available otherwise refer to table 6 3 3 6 3 3 SURFACE WATER Surface water conductivity should be measured in situ if possible oth erwise determine conductivity in discrete samples collected from a sample splitter or compositing device Filtered samples may be needed if the concentrations of suspended material interfere with obtaining a stable measurement In situ measurement Conductivity measurements in flowing surface water should represent the cross sectional mean or median conductivity at the time of observa tion see step 7 below Any deviation from this convention must be documented in the data base and with the
13. LOT 807 670 SET L 6 L 6 8 6 6 6 POT STOT DOT 80 670 60 O IT OEE 8 6 6 6 6 6 9707 9 0T LOT 870 8 0T 6 OT 6 6 901 90 90 EOT 90 GOT GOT 07 OTOL T OT COL 90 LOT 270 Sg OL GOT OTE T IL TE TT t IL SEE OT EOT POT 907 9707 70 OT 60 6 0I O IT ett HTT HTT O TI EOT FOL SOT SOT SOE A 0L 8 0E 8 0L 60 TTE IE FRE v LE STE STI AEL SOT 5707 JOT ETOT 60 PTT S IL 8711 O OT SOT 9 01 LOT 6 OI 607 IT PIT S IL OTE OTE 8 IT ETE 6 Tt 476 AOT 8707 807 60 O II ETE S IL 9717 L II 6 TT QET 076 2707 6707 O LL LI II IL t IL v LL v TL 56 O T TET eT 878 6 OT OEE IT LL LE E LE TY EL STT LIT 8 IL IL TOL C L 0 8 OTE STL v IL S tL 971 STIL ZZ IL 8 IL 6 IL OCCT PET Vv ct SCL S L Ete ETE PIT 9 LTE
14. the YSI 6026 can be factory adjusted to read turbidities up to 4 000 FNU allowing readings to be obtained that would otherwise be off scale The adjustment however is specific to the individual instrument with calibration being non linear between 1 000 and 4 000 FNU hence Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 43 readings in this high range are not reproducible between instruments M Lizotte YSI Environmental written commun May 2003 Any such adjustments made to an instrument s operating range must be documented in the instrument s logbook and in applicable field notes Dynamic determination generally reflects the dynamic conditions in a water body more accurately than static measurements of discrete samples because it avoids problems of particle settling Instrumentation of this type however is not approved by the USEPA for evaluating drinking water The following procedures apply to in situ determination and to determination of turbidity in a flowthrough chamber 1 Calibrate the instrument in the laboratory or office using a cali bration solution before leaving for the field see section 6 7 2 2 At the field site verify that the instrument has retained its calibration within 5 percent If it fails verification then the instrument must be recalibrated 3 Follow procedures for selection of surface water and ground water sampling locations and for dynamic Proce
15. 14 14 6 1 3 B Surface water 22 2 50 15 6 1 3 C Gound 00 4 17 6 1 4 Troubleshooting e eee eere eene eene 18 6 1 5 eere 19 Selected references eere eee eese eese 20 Acknowledgments eee ee eee esee sees eet aas se t ee sooo es 22 Tables 6 1 1 Equipment and supplies used for measuring temperature 4 6 1 2 Troubleshooting guide for temperature measurement ce esee ee eee eren eene eena 18 Chapter A6 Field Measurements Temperature Version 2 3 2006 T 1 2 T Page left blank intentionally Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 3 TEMPERATURE 6 1 Measurements of air and water temperature at a field site are essential for water quality data collection Determination of dissolved oxygen concentrations conductivity pH rate and equilibria of chemical reac tions biological activity and fluid properties relies on accurate tem perature measurements Accurate air and water temper ature data are essential to docu ment thermal alterations to the TEMPERATURE environment caused by natural a measure of phenomena and by human activ warmth or coldness ities Water tempera
16. Instrument reads inaccurate temperature Faulty thermistor repair or replace Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 25 SPECTROPHOTOMETRIC METHOD 6 22 Spectrophotometric methods described by Chemetrics Inc are recom mended for accurate determination of DO concentrations in suboxic waters over a concentration range of 0 1 mg L to approximately 1 0 mg L The Rhodazine D colorimetric method minimizes atmospheric interaction with the water sampled ASTM D 5543 94 2005 White and others 1990 http www chemetrics com catalogpdfs html accessed May 15 2006 gt The accuracy of the method is 10 percent at 75 percent of full range 20 percent at 25 percent of full range and 30 percent at the CHEMetrics practical detection limit Thetechnique was developed for ground water but it can be adapted for work in anoxic zones of lakes and reservoirs EQUIPMENT AND SUPPLIES 6 2 2 Two sampling systems can be used an in situ submersible or downhole sampler see White and others 1990 or a plastic overflow cell through which sample water is pumped Either sampling system uses partially evacu ated oxygen free glass ampoules containing Rhodazine D that are broken along a prescored capillary tip while they are submerged in the water to be analyzed Equipment and supplies needed for this method are listed in table 6 2 4 7Dissolved oxygen conce
17. 47017 4501 8 0L 6 O0L L EL OP TE STD LL BALE 6 LE OTET 07 TOOL SOL 59707 72201 807 E OLOO TE L IL TY LL S Lb 8 LE GILL 9 St SOG POT AG UE GOT TIL C ID SEL PULL s0 GL TOCE COL ECL ove L OF 8 0 6 0E O TE TOTE SIR LE VIL FTE S IL 9 Th 6 EE OZE Tet POCE 876 STOT OTI TTE EAGER 6700 ECOLE PTE So Ch 9ULLE ETTE BOLE OTE Leth C 6L OC CL 2926 072 TITL OCULI 8 TEs 06 IT OCR ESOL ESR OS CL G cI SL C IT t IL SIL OTE 9 IL BTE GTE OET Cl v CL S ct 9 CL cL 8 ek E ZE OET SLL PTE SOLL OTE AE SLF 610 Oleh CL BCL 0 LD TEL TET 470 SEE AELE EL G TE Oc SE ECE Seek 78767 6 SOCEL 070 009 409 019 ST9 029 929 059 959 079 979 049 449 099 499 029 SL9 089 489 069 469 Jo JO ur 4 orazeudsouav penunuoj seJnssaJd pue sainjesadwa jo 9 0 79 279 19 1 U S Geological Survey TWRI Book 9 Dissolved Oxygen Version 2 1 6 2006 DO 39
18. 6 0 e Keep flow constant and laminar e Allow the sensors to equilibrate with ground water tempera ture for 5 minutes or more at the flow rate to be used for col lecting all other samples 4 Measure conductivity and associated temperature at regular inter vals throughout purging record the conductivity values and the associated temperature in the field notes e Ifthe conductivity sensor contains calibrated thermistor use this thermistor to measure water temperature e If the instrument is not temperature compensating install a cal ibrated thermometer in the flowthrough chamber record raw data and apply correction factors 5 Check the variability of the conductivity values toward the end of purging e The stability criterion is met when five readings taken at regu larly spaced intervals of 3 to 5 minutes or more are within 5 percent for conductivity X100 uS cm 3 percent for conductivity 2100 uS cm Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 18 5 e When readings fluctuate rapidly record the median of three or more readings within about 60 seconds as the value for a spe cific time interval e If the criterion is not met extend the purge period in accor dance with study objectives and continue to record measure ments at regularly spaced time intervals Record this difficulty on the field forms 6 Report conductivity e Record the final five values on field
19. MANDATORY FOR NWIS Revised 04 00 APPENDIX 3 VIRGINIA DISTRICT OFFICE RIVER INPUT MONITORING FIELD SHEET THINK TWICE WORK SAFE Version 3 04 2003 b 4 0 S GEOLOGICAL SURVEY SURFACE WATER QUALITY NOTES USGS L science for a changing world nasi utr or Tue reat NWIS RECORD NO STATION NO SAMPLE DATE l I MEAN SAMPLE TIME CLOCK _ STATION NAME SAMPLE MEDIUM SAMPLE TYPE TIME DATUM eg EST EDT UTC PROJECT NO PROJ NAME SAMPLE PURPOSE 71999 __ PURPOSE OF SITE VISIT 50280 __ SAMPLING TEAM TEAM LEAD SIGNATURE DATE_ START TIME GAGE HT GHT TIME END TIME GHT QC SAMPLE COLLECTED EQUIP BLANK FIELDBLANK SPLIT___ CONCURRENT SEQUENTIAL SPIKE TRIPBLANK OTHER NWIS RECORD NOS LABORATORY INFORMATION SAMPLES COLLECTED NUTRIENTS __ MAJORIONS TRACE ELEMENTS FILTERED ____ UNFILTERED __ MERCURY VOC RADON TPC voLFiUTERED mL TPC ___ VOLFILTERED____mL PIC voLFILTERED mL DOC ORGANICS FILTERED UNFILTERED ___ ISOTOPES _ MICROBIOLOGY CHLOROPHYLL BOD COD ALGAE INVERTEBRATES FISH BEDSED SUSP SED sr size RADIOCHEMICALS FILTERED ___ UNFILTERED OTHER OTHER LABORATORY SCHEDULES LAB CODES ADD DELETE ADD DELETE ADD DELETE ADD DELETE ADD DELETE ADD DELETE COMMENTS DATE SHIPPED I FIELD MEASUREMENTS GAGE HT 00065 ft 00095 uSicm 25 CARBONATE 00452 mg L Q iNST 00061 meas Ratne est
20. Wilde F D and Radtke D B 2005 General information and guidelines ver 1 2 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A6 section 6 0 August available online only at http water usgs gov owq FieldManual Chapter6 6 0_contents html Accessed September 8 2008 Wilde F D ed 2006 Collection of water samples ver 2 0 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A4 September available online only at http pubs water usgs gov twri9A4 Accessed September 8 2008 Wilde F D Radtke D B Gibs Jacob and Iwatsubo R T eds 2004 Processing of water samples ver 2 2 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A5 September available online only at http pubs water usgs gov twri9A5 Accessed September 8 2008 Wood W W 1981 Guidelines for collection and field analysis of ground water samples for selected unstable constituents U S Geological Survey Techniques of Water Resources Investigations book 1 chap D2 p 12 Chapter A6 Field Measurements pH Version 2 0 10 2008 30 pH 6 4 8 ACKNOWLEDGMENTS The authors wish to thank the following USGS scientists for their technical assistance and review of this section of the National Field Manual D H Campbell and J M Galloway who provided peer review and F D Wilde managing editor of the National Field Manual Appreciation for edit
21. 1 interferences table 6 7 2 sampling and subsampling techniques instrument drift biofouling sensor damage different operators and different protocols being employed Bias in turbidity is quantified through measurements of turbidity against known calibration solutions at different times using different instrumentation or with different methods This is particularly important before and after a measurement series either in a laboratory or when servicing a continuous monitor in the field Following are examples of quality assurance tests that can be performed periodically for static or dynamic determinations of turbidity gt Instrument Drift After a series of measurements and prior to calibration measure turbidity using known calibrants including turbidity free water or zero turbidity calibration solution and a calibration or check solution near the maximum calibrated range Record the turbidity before making any adjustments to instrument calibration Bias is computed as the percent difference between readings before calibration and readings at the same range after calibration Instrument drift is most important to document in continuous monitoring applications Fouling After a series of measurements and before calibration measure source water turbidity using known calibrants including turbidity free water or zero turbidity calibration solution and a calibration or check solution near the maximum calibrated range
22. 32 TBY Spectrophotometric turbidimeter calibration Spectrophotometric turbidity measurements sometimes referred to as absorbtometric or attenuation turbidity are useful to indicate relative values or to monitor changes in turbidity with time Spectrophotometers however measure light transmission rather than light scattering using a narrow short wavelength light source are inaccurate for absolute turbidity measurement and are unrated for instrument sensitivity Most of the spectrophotometers used for measuring turbidity are benchtop or portable instruments so sample handling is similar to that described for benchtop static turbidimeters gt Use spectrophotometry as an indication of optical properties in water only upon careful review of study objectives and alternative available technology Instrument response is negative that is the detector response decreases with increasing turbidity which is the opposite of traditional turbidity and backscatter instrument responses Report results in Attenuation Units AU or Formazin Attenuation Units FAU depending on the light source table 6 7 4 The overwhelming majority of available spectrophotometric turbidity instruments use FAU Spectrophotometers commonly have a stored program for turbidity that has been factory calibrated and that can be verified but not adjusted Check the instrument output against that of a different instrument every few weeks while the instrumen
23. 6 v 6 57 6 476 976 476 876 876 676 00 TOT OTE 8 8 8 8 6 8 0 6 T 6 276 576 v 6 v 6 S 6 9 6 L 6 L 6 8 6 6 6 6 6 0707 S 0T 6 8 6 8 076 T 6 276 276 gt 6 776 476 476 976 476 876 876 676 07071 OI 0 0T 0 6 0 6 6 6 t 6 v 6 v 6 S 6 9 6 476 476 876 676 90707 O OI FOT 476 276 276 6 776 476 476 976 476 876 876 676 07071 OT S OI S OI 076 6 EG EG v 6 476 976 476 4176 876 676 907071 070 EOT POT Fv OL S OT 9 0T LOT 4578 t 6 776 476 476 976 476 876 676 676 0 01 POT 40 970 970 L OI 8 0T 078 776 876 976 476 476 876 676 0 O0L LOL L OL c OL T OL S O0D 470 DOT 87 05 6207 6 OL SE 476 976 4176 876 676 676 907071 EOT EOT 40 9 0T 70 L OI 870 6 0T Q TE TTE 074 476 476 876 676 07071 LOL TOE C OL OL OL SOT 9 0T 9 05 L OT 8 OL OQ IL O IL TTT ILI 4879 876 676 676 0 01 970 70 8 OT 670 EOT ESTL HIT 079 676 OT 4 0 90 S OL 60 TIT IT ete lt 874 TOT COT E OR S OL SOT 9502 4701 8201 6 0L OF TT TTL Tih g EE SEE 9 EE 9 EL 074 0T OT FP OL 9 OE 4 07 870 6 0I o OL OI T IL C IT PTI S IL 9 CE A IT St 0I S OE
24. Verify that the instrument reading is within 0 2 mg L of the computed satura tion value or use more stringent accuracy criteria per the data quality objectives of the study The instrument is now calibrated and ready for use Remove the sensor from the calibration cham ber Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 19 TECHNICAL NOTE The 5 5075A calibration chamber is designed to allow the membrane surface of a DO electrode model 5739 to be at ambient atmospheric pressure while in the chamber Because the pressure compensating diaphragm must remain at atmospheric pressure check the calibration chamber vent tube from the chamber through the end of the handle to ensure that it is not plugged with debris or filled with water MEASUREMENT 62 1 C The solubility of oxygen in water depends on the partial pressure of oxy gen in air the temperature of the water and the dissolved solids content of the water gt The higher the atmospheric pressure and the lower the temperature and conductivity the more oxygen can be dissolved in the water gt Degassing mineral precipitation and other chemical physical and biological reactions can cause the DO concentration of a water sample to change substantially within minutes after sample collection These sample reactions are especially important when sampling ground water that is not in equilibrium with the atmosphere The solubility
25. cc o m o o r c o i BOR BS ES E a d o o D d o p o E i aa axe N QUAE eer an 7 o RUE SN Ch apter A6 Fie Id M easu rem ents Di ssolv ed O xyge n Ve rsion 2 1 6 20 06 40 DO o o corr tm MAN NHHOO o acu ut uec Cue AN den e e Ln un Ln 0 in in in in nn 10 100 n oc or 0 S 0mm NNHHO o S lleva xi a Vase rue ee e ODE E TRU a nnn nin un in in in in an D DS iow tom o v 10 100 10 1n wn in in in in In in in an Lo Dnt tm MOANA A V vo 00 10 10 in in in in in nn 100 10 oun in an o c NNNMNN v wn in in in in inn 100 100 ou T v v Po 10 in 00 in o rco o cort 49 00 o in in H 2
26. ination and dilution The sonde sensor guard may need to be removed Procedure B Immersion of turbidity sensor only depend ing on sonde configuration isolation of the turbidity sensor and achieving a bubble free optical surface could be difficult This technique minimizes the volume of calibrant required for calibration 3 Determine the number of calibration points to be used a minimum of two but three is preferred and configure the instrument for this number of points if applicable Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 31 4 For a zero turbidity unit calibrant or turbidity free water a Rinse sonde sensor with deionized water followed by a portion of the turbidity calibrant b Immerse sensor in calibrant or add enough calibrant to cover the sensor in the calibration chamber c Agitate the sonde sensor repeatedly to remove bubbles from the optical surface activate mechanical wiper if present d Set sensor vertically on a flat surface or use a ringstand to hold it e Monitor turbidity readings for 1 to 2 minutes or longer to ensure that readings are stable consult manufacturer s recommendations and signal processing information Record the pre calibration value in the instrument logbook or on the field sheet f Confirm the calibration value or adjust the instrument calibration using the manufacturer s instructions g Remove the sonde sensor and dry thoroughly t
27. o o 5 o E 1 o i o Lm x o ne i lt o _ Sc o tec o o a m o i y o v 5 5 09 E E n mM Ne Sos wo m d o o _ m o o n o E i o m sec wo Te w o o NK Qu XD up o o o n m NON E a ane wo ps na n o m EM BEND o o o m o 2 N m o 9 I soc EU o d d o nn o wv vu 3 n o m o o m i pe m o wo N eg Acc o n o v wo c n o o 3 1S fa m i mna AP n S o i cz E Oo AD AD o n vd E pA m 1 o o D m NON EU v wo gt o 0 o i VN e o REX o o o o
28. wade to the location s where tem perature is to be measured To prevent erroneous readings caused by direct solar radiation stand so that a shadow is cast on the site for temperature measurement e Stream too deep or swift to wade measure temperature by lowering from a bridge cableway or boat a thermistor ther mometer attached to a weighted cable Do not attach a weight directly onto the sensor or sensor cable e Still water conditions measure temperature at multiple depths at several points in the cross section Chapter A6 Field Measurements Temperature Version 2 3 2006 3 Immerse the sensor in the water to the correct depth and hold it there for no less than 60 seconds or according to the manufac turer s guidelines until the sensor equilibrates thermally The sensor must be immersed properly while reading the temperature this might require attaching the thermistor to a weighted cable TECHNICAL NOTE For in situ measurement with liquid filled full immersion thermometers the water depth to which the thermometer is immersed must be no greater than twice the length of the liquid column of the thermometer in order to make an accurate measurement 4 Read the temperature to the nearest 0 5 C for liquid in glass and 0 2 C for thermistor readings do not remove the sensor from the water e Whenusing a liquid in glass thermometer check the reading three times and record on field forms the median of these values
29. 8 2005 U S Geological Survey TWRI Book 9 SC 15 6 Measure water temperature e If the conductivity sensor contains a calibrated thermistor use this thermistor to measure water temperature e Ifthe instrument is not temperature compensating use a cali brated thermistor or a liquid in glass thermometer e Adjust the instrument to the sample temperature if necessary and remove the thermometer 7 Measure conductivity a Remove any air trapped in the sensor by agitating the sensor up and down under the water surface b Read the instrument display c Agitate the sensor up and down under the water surface and read the display again d Repeatthe procedure until consecutive readings are the same 8 Record the conductivity and the sample temperature on field forms e If the instrument is not temperature compensating record the raw data and convert the values to conductivity at 25 C using temperature correction factors provided by the manufacturer e Report the median of the readings to three significant figures on the field forms e Discard the sample into a waste container and dispose accord ing to regulations 9 Quality control e Repeat steps 3 through 8 with at least two fresh subsamples rinsing the instruments once only with sample water e Subsample values should be within 5 percent for conductivity lt 100 uS cm or 3 percent for conductivity gt 100 uS cm e If criteria cannot be met filte
30. D E wid Zn Cod sed tua Sab gia D rel teet LIN i MA Mie es o ORO o YMM NNHOO o EX Qus ene cues qeu eus 5 BOR BOR BOR o o wn In o v wont tm MANNO a ree ieee o NE Ig P qui Saks ty a a se ap ata att a BOR BOR BORD T N 5 Q eo Eu onono nonon onono o lt A oh Wat Sap du o Police e tas a 9 E Noo 5 9 9 9 Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 38 DO 0 9 T 8 Ts 8 659 Eg v 8 9 8 478 978 178 178 878 678 678 076 176 c e 6 6 4877 28 278 278 678 778 778 478 978 978 478 878 878 678 076 076 T 6 c 6 t 6 t 6 v 6 0 278 278 678 778 478 478 978 4178 478 878 678 678 076 T6 T 6 276 E v 6 v 6 S 6 S tTI 8 8 v 8 478 478 978 178 878 878 678 076 076 T6 276 E76 6 v 6 S 6 6 6 9 6 0 v 8 v 8 S 8 9 8 9 8 L 8 8 8 6 8 6 8 0 6 176 176 26 t 6 v 6 v 6 476 976 976 176 87 lt 478 478 9 8 L 8 L 8 8 8 6 8 0 6 0 6 T 6 C6 6 6 v 6 S 6 576 976 L76 876 876 O ZI 9 8 9 8 L 8 8 8 878 678 076 176 176 26 6 776 776 476 976 976 476 876 676 676 S IT L 8 L 8 8 8 6 8 0 6 0 6 T 6 6 6
31. Division of Consolidated Laboratory Services Method 2 510 The Determination of Chlorophylls A B amp C in Marine and Freshwater Algae by Visible Spectrophotometry Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2523 Determination of Ammonia Nitrogen by Automated Colorimetry Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2525 Total Dissolved Nitrogen and Method 2540 Total Dissolved Phosphorus Automated Colorimetric Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2526 Nitrate Plus Nitrite Nitrogen in Estuarine and Coastal Waters Low level Automated Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2532 Carbon Total Organic and Dissolved Organic Carbon Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2538 Phosphorus Orthophosphate Low Level Automated Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2539 Determination of Phosphorus in Sediments and Particulates of Estuarine Coastal Waters Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2543 Molybdate Reactive Silica in Water and Wastewater Comm
32. EVERY TIME APPENDIX 4 STANDARD OPERATING PROCEDURES FOR THE COLLECTION OF FIELD PARAMETERS pH Specific Conductance Dissolved Oxygen Turbidity and Temperature AND CHLOROPHYLL a 40 pH 1 pH 6 4 Revised by George F Ritz and Jim A Collins Page AAEE E pH 3 6 4 1 Equipment and supplies eessoosssssooccescsoocccsssoooccesssoocessssoosessssooosessssosessssocsscessccsesesocesseseo 4 6 4 T A Fave e 6 6 4 T B pH electrodes neces eoo 6 6 4 T C pH buffer Solutions POS a obese PR anu 9 6 4 2 Maintenance of pH instruments 10 6 4 2 4 Electrode care and cleaning eee eee e eee eee eee eee eee teens eese 10 6 4 2 B Reconditioning of liquid filled electrodes 12 6 4 2 Electrode Storage eene 13 6 4 3 Calibration of the pH instrument 14 6 4 3 A Calibration procedure under standard aqueous conditions 16 6 4 3 B Calibration for low ionic strength water
33. MEDIAN NTU REMARK QUALIFIER DIGITAL PICTURE OF SITE CAN BE INSERTED HERE COMMENTS CALCULATIONS REFERENCE LIST FOR CODES USED ON THIS FORM Time Datum Codes Sample Medium Codes Std UTC Daylight UTC 9 Surface water Time Offset Time R Quality control sample associated environmental Time Zone Code hours Code hours sample 9 SW Hawaii Aleutian HST 10 HDT 9 Q Blanks Alaska AKST 9 AKDT 8 Pacific PST PDT 7 Sample Type Code Mountain MST MDT 6 9 Regular Central CST CDT 5 7 Replicate Eastern EST EDT 2 Blank Atlantic AST ADT 1 Spike 82398 SAMPLING METHOD Null value Qualifiers Value Qualifiers Equal Width Increment Ewi e required equipment not functional or available e see field comment Equal Discharge Increment Edi f sample discarded improper filter used f sample field preparation problem Timed Sampling Interval o insufficient amount of water k counts outside the acceptable range Single Vertical Multiple Verticals Point Sample Grab Sample Dip Discharge Integrated Equal Transit Rate Etr Discharge Integrated Centroid 71999 SAMPLE PURPOSE 84164 SAMPLER TYPE Routine 100 Van Dorn Sampler NAWQA 110 Sewage Sampler N UN s Integrated 125 Kemmerer Bottle Benchmark 25 MES 3039 US D 77 Tm SW Network rab Sample ater Supply Tap 3040 US D 77 Tm Modified Teflon Bag Sampler Lowflow Network 3044 USDH 81 Highflow Network 50280 PURPOSE OF SIT
34. To convert from digital counts to milliliters divide by 800 1 00 mL 800 counts NOTE For samples with pH gt 9 2 these equations for bicarbonate and carbonate will fail to give accurate results Use the Alkalinity Calculator at http oregon usgs gov alk HACH CARTRIDGE CORRECTION FACTOR SEE QWQRL WEB PAGE NEWS FOR INFO FIRST TITRATION RESULTS SECOND TITRATION RESULTS COMMENTS CALCULATIONS DATE I DATE TEMP TIME TIME ALKALINITY ANC ALKALINITY ANC meq L mg L AS CACO3 ALKALINITY ANC meq L ALKALINITY ANC mg L CACOs BICARBONATE mg L meq L As BICARBONATE mg L meq L As HCO CARBONATE CARBONATE mg L meq L As CO 32 ACID 1 6N 0 16N 0 01639 OTHER ACID LOT NO ACID EXPIRATION DATE I mg L meq L As 3 ACID 1 6N 0 16N 0 01639 OTHER ACID LOT NO ACID EXPIRATION DATE I I SAMPLE VOLUME SAMPLE VOLUME mL FILTERED __ UNFILTERED FILTERED __ UNFILTERED INFLECTION POINT TITRATION ___ INFLECTION POINT TITRATION ___ GRAN METHOD GRAN METHOD STIRRING METHOD ___ MAGNETIC ___ MANUAL STIRRING METHOD ___ MAGNETIC ___ MANUAL STN NO MICROBIOLOGY FECAL COLIFORM TOTAL COLIFORM E COLI Time collected 2 Time collected Time collected _ time in at 35 date time in at 44 5 C date time out date time out date time out date VOLUME COUNT USED IN REMARKS
35. Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 45 SPECTROPHOTOMETRIC 6 7 3 C DETERMINATION The attenuation method described below uses a field spectrophotometer to provide a relative measure of the sample turbidity The spectrophotometer directs a beam of light through the sample at a specific wavelength and measures the amount of transmitted light reaching the transmitted detector fig 6 7 1 The decrease in the detected light intensity caused by absorption or scattering in the sample is calibrated to accepted calibration turbidity solutions see 6 7 1 C Spectrophotometric measurement of turbidity yields readings in AU or FAU depending on the light source gt This method is not approved by the USEPA and is subject to many interferences It is a useful method for example if the purpose for the turbidity determination is as an indicator of ambient or stabilized conditions during well development or purging Turbidity values less than 50 FAU the range for most surface water and ground water are inaccurate using this method and the procedure is recommended only as a measure of relative turbidity among different samples FAU is equivalent to NTU when measuring formazin but they are not necessarily equivalent when measuring water samples or other types of standards Relations among different instrument types are site specific Be careful to enter absorption derived turbidity values into the d
36. charge polarization on the exterior of the pH electrode which can also adversely affect the pH measurement Chapter A6 Field Measurements pH Version 2 0 10 2008 12 pH 6 4 2 8 RECONDITIONING OF LIQUID FILLED ELECTRODES If problems persist during calibration of a liquid filled electrode or if there is reason to doubt that the electrode is in good working condition check the manufacturer s instructions for how to test and recondition the electrode Reconditioning procedures should be implemented only if the electrode s slope response has deteriorated to less than 95 percent Document in the pH meter electrode logbook if the electrode has been reconditioned or replaced The following general procedures can be used to attempt to bring the liquid filled electrode back into proper working condition 1 Remove the old filling solution from the electrode a Place the needle of a 1 or 3 milliliter mL syringe into the electrode filling hole or use other methods of removing the filling solution such as vacuum extraction or draining b Tilt the pH electrode until the filling solution is near the fill hole and the needle tip is covered with the filling solution c Pull back on the syringe plunger until the syringe is full d Discharge the solution from the syringe into a waste container and repeat steps 1 a through d until all of the filling solution has been removed from the pH electrode 2 Flush the pH electrode wit
37. e e EEIBIU The area of the James River Basin is approximately 10 206 mi or about one fourth of the area of Virginia and is the third largest source of freshwater to the Chesapeake Bay after the Susquehanna and Potomac Rivers The James River Basin extends from the eastern part of West Virginia through four physiographic provinces 1 Valley and Ridge 2 Blue Ridge 3 Piedmont and 4 Coastal Plain The major cities in the James River Basin include Richmond Lynchburg Petersburg Charlottesville Williamsburg Hopewell and parts of Norfolk and Newport News The water quality monitoring station at the James River near Cartersville Va USGS station 02035000 and VDEQ station 2 JMS157 28 Discontinued 3 2001 represents the contributing area 6 257 mi to the Chesapeake Bay from Virginia near the Fall Line or about 60 percent of the James River Basin drainage area This station is about 40 mi upstream of the Fall Line but was selected because of the well documented long term flow record and because there are no major streams contributing to the flow between this station and the Fall Line at Richmond Because of the size of the basin upstream of the sampling station streamflow varies widely depending on precipitation patterns which may result in either very localized or widespread stormflow events The average discharge at this site computed during a period of 94 years is 7 077 ft s Prugh and others 1994 The location of this m
38. nutrients and suspended solids for periods of varying flow and season which are used to produce estimates of constituent loading to the Chesapeake Bay The specific objectives of this program are to 1 describe concentrations of selected nutrients and suspended solids in terms of flow and season 2 compute monthly and annual loads of nutrients and suspended solids 3 compare concentration data and load estimates between rivers 4 compute trends in nutrient and suspended solid loads over time 5 explain possible factors influencing concentration loads and trends of nutrients and suspended solids 6 provide data for calibration of the Chesapeake Bay Watershed model and nutrient and sediment loading inputs to the Chesapeake Bay Water Quality model 7 assess quality assurance results in order to describe the quality of the analyses provided by the participating laboratories and 8 provide information needed to refine the network design for future monitoring programs for the Chesapeake Bay The stations monitored and their station numbers include 1 the James River at Cartersville 2 the Rappahannock River near Fredericksburg 3 the Appomattox River at Matoaca 4 the Pamunkey River near Hanover 5 the Mattaponi River near Beulahville 6 the North Fork Shenandoah River near Strasburg 7 the South Fork Shenandoah River at Front Royal 8 the Rapidan River near Culpeper 9 the James River at Blue Ridge P
39. 0006 0008 0004 0009 0005 0007 000 0002 000 0 SnrS eD sz ur 3 14 jo pue ay snis o2 ag o1 og 1e 510106 uonoeJ100 snis o2 22 dwa 0 61 SSISA qu 41044 uo peseq UBBAXO 10 s4012eJ uon2a4402 Z 9 Dissolved Oxygen Version 2 1 6 2006 Chapter A6 Field Measurements DO 42 06870 968 0 66870 lt 0670 90670 60670 T6 O0 91670 616 0 lt lt 0670 92670 62670 tt 6 0 96670 66670 tv6 0O 9 670 0760 056870 46870 86870 20670 40670 60670 251670 41670 617670 520670 92670 62670 056670 96670 66670 257670 9 670 0782 176870 68 0 86870 710670 40670 80670 11670 41670 87670 20670 42670 82670 26670 46670 86670 77670 4 670 0740 06870 6870 26870 710670 0670 20670 11670 1670 87670 710670 42670 82670 IEG6 0 46670 86670 17670 4 670 0792 68870 66870 96870 00670 80670 20670 01670 1670 271670 712670 2670 10670 16670 vt6 0 86670 IvV6 O 670 0742 68870 206870 96870 66870 80670 90670 01670 1670 271670 02670 2670 12670 06670 670 16670 T6 0 670 0770 88870 76870 46870 86870 20670 40670 60670 21670 9 670 61670 lt 0670 92670 06670 66670 76670 07670 670 0764 18870 I68 0 6870 86870 710670 40670 80670 21670 ST6 0 61670 22670 92670 60670 6670 966
40. 10 TBY Table 6 7 4 Reporting units corresponding to turbidity instrument designs Parameter code numbers begin with a P nm nanometers 9 degree plus or minus K kelvin Detector geometry Light wavelength White or broadband with a peak spectral output of 400 680 nm Monochrome spectral output typically near infrared 780 900 nm Single illumination beam light source At 90 to incident beam Nephelometric Turbidity Unit Formazin Nephelometric readings which may differ for values of varying NTU P63675 Unit FNU P63680 At 90 and other angles An Nephelometric Turbidity Ratio Formazin Nephelometric instrument algorithm usesa Unit NTRU P63676 Ratio Unit FNRU combination of detector P63681 magnitude At 30 15 to incident beam Backscatter Unit BU Formazin Backscatter backscatter P63677 Unit FBU P63682 At 180 to incident beam Attenuation Unit AU Formazin Attenuation attenuation P63678 Unit FAU P63683 Multiple illumination beam light sou At 90 and possibly other angles to each beam An instrument algorithm uses a combination of detector readings which may differ for values of varying magnitude Nephelometric Turbidity Multibeam Unit NTMU P63679 Formazin Nephelometric Multibeam Unit FNMU P63684 Method 180 1 defines the optical geometry for NTU measurements The detector a
41. 44 13 Signal processing options 18 Maintenance of turbidity instruments 18 6 7 2 Calibration eese eee eee 21 6 7 2 4 Calibration solution use preparation and 24 6 7 2 B Calibration procedures 26 Benchtop static turbidimeter calibration 27 Submersible dynamic turbidity sensor calibration ooo erro esr terere 29 Spectrophotometric turbidimeter calibration 32 6 7 33 6 7 3 A Static benchtop determination 34 6 7 3 B Dynamic submersible sensor determination e eeee ecce eere 42 6 7 3 Spectrophotometric determination 45 Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 2 TBY 6 7 4 Quality assurance procedures 47 6 7 4 A 47 6 7 4 B Bia Rt 49 6 7 5 Data reporting and interpretation 50 6 7 6 Troubleshooting ee en ee eee eee 52 Selected references eere rente 53 Illustrations 6 7 1 Photoelectric nephelometer single beam design showing optional additional detectors for ratiometric backscatter or transmitted determination of t rbidiIty ierit e
42. 4870 19870 49870 89870 ZL8 0 9 870 64870 O LT 618 0 00870 902870 06870 8 0 86870 TPE O 978 0 678 0 4870 95870 098 0 v98 0 L98 0 870 4 870 64870 079 11870 70870 40870 60870 6870 96870 0 870 870 87870 204870 44870 64870 98 0 79870 0 870 870 8 870 OST 97870 00870 v28 0 80870 06870 46870 66870 E v8 0 LvV8 O0O 14870 vS8 0 84870 209870 99870 69870 L8 O LL8 O SI8 0 6T8 O0 0870 LC8 0 06870 7 8 0 86870 07870 97870 098 0 98 0 458 0 98 0 459870 69870 cL8 O 94870 0 718 0 81870 00870 SC8 0 60870 lt 6870 6870 870 4 870 67870 04870 998 0 09870 9870 89870 8 0 9480 072 I8 0 41870 002870 vc8 0 80870 068740 96870 0 870 PPE O 87870 158 0 45870 64870 lt 9870 279870 870 vL8 O OTE TT8 O 41870 61870 amp 58 0 LC8 0 870 46870 66870 870 97870 04870 74870 84870 29870 99870 048 0 7 870 070 OI8 0 vIS8 0O 81870 20870 90870 06870 7 870 86870 7870 47870 67870 98 0 4870 79870 49870 69870 L8 O 076 60870 80 21870 12870 40870 60870 6870 6870 078 0 870 87870 25870 94870 09870 9870 89870 24870 078 80870 1870 91870 00870 208 70 80870 870 46870 66870 7870 7870 14870 44870 64870 69870 279870 IL8 O 074 90870 017870 vI8 0O BTE O 20870 92870 06870 PESO 86870 27870 97870 05870 98 0 84870 29870 99870 0480 0 9 40870 60870 T8 O0 71870 120870 40870 60870 6870 76870 7870 47870 6 870 64870 4870 79870 49870 69870 074 70870 80870 2 8 0 9 87 0 00870 8 0 820870 06870 96870 0870
43. 6 2006 8 DO Before each field trip Check the instrument batteries and all electrical connections 2 When using an amperometric instrument inspect the sensor closely checking for any loose wrinkled or torn membrane air bubbles beneath the membrane and a tarnished or discolored cath ode or anode If any of these problems are detected do not use the sensor until it has been serviced according to the manufacturer s recommendations 3 Test instrument calibration Do not use an instrument that fails to calibrate properly Service the instrument according to the manu facturer s recommendations and recalibrate 4 Test the instrument to ensure that it will read zero in a freshly pre pared zero DO solution For amperometric instruments e Ifthe instrument reading exceeds 0 2 mg L then the sensor membrane and electrolyte if present need to be replaced or the sensor needs to be repaired e Before repairing or replacing the sensor check zero DO again with a freshly prepared zero DO solution 5 Check the calibration with a pocket altimeter barometer If neces sary recalibrate following the manufacturer s recommendations CAUTION Before handling any chemicals refer to the Material Safety Data Sheet MSDs for safety precautions Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 9 The relation between sensor membranes and temperature must be rec ognized DO sensors must
44. 7 6 Guidelines for reporting turbidity units For ASTM and USGS measurements refer to table 6 7 3 for reporting units based on instrument design Abbreviations USGS U S Geological Survey ASTM ASTM International EPA 180 1 U S Environmental Protection Agency method 180 1 1993 GLI Great Lakes Instruments ISO 7027 International Organization for Standardization method 7027 1999 NTU nephelometric turbidity units FNMU Formazin Nephelometric Multibeam Units FNU Formazin Nephelometric Units N A not applicable lt less than gt equal to or greater than Turbidit EPA 180 1 GLI Method 2 ISO 7027 Reading USCS ASTM FNMU FNU 0 lt 1 0 05 0 05 0 05 0 05 0 01 1 lt 10 4 4 4 NI 4 10 lt 40 1 1 1 1 1 40 lt 100 1 1 5 5 N A 100 400 10 10 10 10 N A 400 lt 1 000 10 10 50 50 gt 1 000 50 50 100 100 Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 52 TBY 6 76 TROUBLESHOOTING Consult the instrument manufacturer for additional guidance if the suggestions shown on table 6 7 7 do not remedy the problem encountered Table 6 7 7 Troubleshooting guide for field turbidity measurement Symptom Possible cause and corrective action Erratic reading Check voltage of the batteries replace weak batteries with new batteries Condensation on cell wall of static turbidimeter see Moisture symptom Bubbles in sampling system or on opti
45. 7 for salin ity corrections Skip to Step 9 if using an amperometric instrument Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 16 DO 8 For luminescent sensor instruments Following the manufac turer s instrument calibration instructions verify that the instru ment reading is within 0 2 mg L of the computed saturation value Alternatively apply a more stringent accuracy criterion that reflects study data quality requirements The luminescent sensor instrument is now calibrated and ready for use 9 For amperometric instruments Adequate flow of water across the surface of the membrane is required for accurate measure ments Recommendations for flow velocity vary by manufacturer with most recommending about 1 foot per second ft s e Provide suitable turbulence in the air saturated water by phys ical or mechanical means to maintain the required flow rate past the membrane avoiding the creation of air bubbles at the water sensor interface e Maintain this flow rate when making measurements and adjusting instrument calibration 10 For amperometric instruments Turn off the aerator and take care to prevent any air bubbles from adhering to the membrane Following the manufacturer s instructions set or adjust the cali bration control until the instrument reads a saturation value of DO as determined above Verify that the instrument reading is within 0 2 mg L of the computed saturation val
46. 99 70 OLL O SLL O I8L O 48 70 68 70 6L 0 16270 70870 40870 60870 O IT SPEO GPL 0 4 70 LSL O O9L O v9L O 89L O ZLL O 9LL O 08470 v8L O 88 70 e6L 0 96L O0O 00870 0870 L08 0 0 0T EPL OO LVL O ISL O SSL O 64 70 69 70 L9L O ILL O SLL O 6LL O t 8L O L8L O 06470 v6L O 86 70 20870 90870 0 6 CPL O SvVL O 6vVL O ESL O LSL O I9L O S9L O 69L O ELL O LLL O ISL O 48 70 68L 0 t 6L O 46270 70870 40870 078 TvVL O 8 0 4 70 94 70 09 70 v9L O 89 70 ZLL O 91470 08 70 v8L O 88 70 256 70 96 70 00870 0870 074 8670 CPE O 9vL O 04 70 vSL O 84 70 09 70 99 70 044270 vLL O 81170 58470 98 70 06 70 veL O 86 70 2050870 079 16470 IVL O SPEO 6vL O 4 70 14 70 794 70 49 70 69 70 ELETO 14270 I8L O 48470 68 70 t 6L 0 46 70 70870 074 86 70 6670 OPLO LvVL O 14 70 44 70 64470 lt 9 70 19 70 ILL O 44 70 08 70 v8L O0O 88 70 26 70 96 70 00870 07 0 16470 IVL O 9vL O 04 70 vSL O 84 70 29 70 99 70 04470 vLL O 81270 28470 98 70 06 70 6 70 86 70 DE 06470 9EL O OTL O vVvVL O 8vVL O ZSL O 9SL O 09 70 vV9L O 89 70 ELL O LLL O ISL O 48 70 68L 0 6L O 16 70 0 c 06 70 TvEL O 8EL O CVvVL O 9vVL O ISL O SSL O 64 70 lt 9 70 L9L O ILL O SLL O 6470 t 8L O0 88L 0 26 70 96 70 80470 CEL O LEL O 70 SvVL O 6vL O ESL O LSL O I9L O 99 70 OLL O vLL O 8470 058470 98 70 06 70 46 70 070 00049 00099 00049 00079 00069 00059 00019 00009 00064 00084 00044 0009S 00099 00074 00064 00024 000 4 90 sz
47. L ferric iron causes a bias of 7ug L The effect from reducible inorganic species can be corrected if the concentrations of the interfering species are known White and others 1990 gt Additional calibration is needed if the method will be used to determine DO in heavily contaminated or acidic waters This can be done by equilibrating a water sample with known partial pressures of atmospheric oxygen White and others 1990 Atmospheric oxygen standards are available from suppliers of gas chromatography equipment Color and turbidity interfere with this test method causing positively biased results If using this method in colored or turbid water first conduct an assessment of the amount of bias attributable to such effects MEASUREMENT 6 22 C Rhodazine D reagent reacts with DO to produce an oxidized com plex characterized by a red blue color The color intensity is propor tional to the concentration of the initial DO present Follow the 8 steps below to measure DO using the spectrophotometric method 1 According to site characteristics and study objectives purge the well following guidelines in NFM 4 2 2 Set the spectrophotometer to a wavelength of 555 nanometers 3 Zero the spectrophotometer using the blank provided in the kit follow the manufacturer s instructions Collect the sample 4 Install either the downhole sampling tool White and others 1990 or use a plastic overflow sampler tube with a sui
48. L liter uS cm microsiemens per centimeter at 25 C Calibration thermometer liquid in glass or electronic thermistor thermometer either National Institute of Standards and Technology NIST certified or manufacturer certified as NIST traceable Must carry certificate of NIST traceability its use not allowed after expiration of certification e Temperature range at least 5 to 45 C e 0 1 C graduations liquid in glass or less v Thermometer liquid in glass sensor nonmercury filled for field use Temperature range at least 5 to 45 e Minimum 0 5 C graduated Calibrated accuracy within 1 percent of full scale or 0 5 C whichever is less Calibrated and office laboratory certified against a properly certified calibration thermometer see above Thermistor Thermometer Calibrated accuracy within 0 1 C to 0 29 Digital readout to at least 0 19 Office laboratory certified against a calibration thermometer see above Dewar flask and or plastic beakers assorted sizes Water bath refrigerated if available see section 6 1 2 Y Y Soap solution 1 1 nonphosphate laboratory detergent Y Deionized water 1 L maximum conductivity of 1 uS cm v Flowthrough chamber for ground water applications as an alternative to instruments with downhole capabilities v Paper tissues disposable soft and lint free v Log book for recording all calibrations maintenance and repairs
49. Properly immerse the calibration and field thermometer s in the water Cover the container and allow the water bath and thermom eters to equilibrate 3 Stir the water and using the calibration thermometer check the bath for temperature uniformity Repeat this every 2 hours It may be necessary to let the bath equilibrate overnight 4 Compare one field thermometer at a time against the calibration thermometer following the procedures described above in step A5 for the 0 C calibration C For each temperature that is greater than 25 1 Warm a beaker of 1 000 mL or more of water to the desired tem perature for example 40 C and place it on a magnetic stirrer plate 2 Follow the procedures described above in step A5 for the 0 cali bration Tag acceptable field thermometers as office laboratory certified with the calibration date and certifier s initials Corrections can be applied to measurements made with a thermometer that is within 1 percent of full scale or 0 5 C of the calibration ther mometer Corrections should be applied by using a calibration curve or table which is plotted in the log book for the instrument Thermistors found to be out of calibration by more than 0 2 C must be returned to the manufacturer for repair or replacement Remember to tag and date acceptable field thermometers after calibration Chapter A6 Field Measurements Temperature Version 2 3 2006 14 T 6 1 3 M
50. Store every component of the pH measuring system in an area that is clean dry and protected from extremely hot or cold temperatures Chapter A6 Field Measurements pH Version 2 0 10 2008 14 pH 6 4 3 CALIBRATION OF THE pH INSTRUMENT SYSTEM Proper calibration of the pH instrument system is crucial to accurate pH measurement of environmental samples During calibration the pH electrodes are immersed in buffer solutions of known pH section 6 4 1 C The buffers are designed to produce a corresponding electrical response potential usually in millivolts for the specific pH buffer for example pH 4 7 or 10 buffer solution within the pH electrode These potentials are measured by the pH meter The Nernst equation gives the expected theoretical response potential of the pH buffer at the specific temperature of the calibration Hem 1989 see TECHNICAL NOTE below Note that the measured temperature must be programmed into the pH meter unless the meter has incorporated automatic temperature compensation The calibration returns the actual measured potential TECHNICAL NOTE pH electrodes operate on the principle that differing concentrations of the H in buffers or environmental samples produce differing potentiometric responses measured in millivolts The Nernst equation is used to establish the calibration of the pH instrument system by determining the slope of electrical potential versus pH at a given temperature At 25 thi
51. a churn cone splitter or other appropriate compositing device 2 2 Remove an aliquot from the sample composite for measurement of pH pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 27 TROUBLESHOOTING 6 4 5 Consult the instrument manufacturer for recommended troubleshooting actions for specific single parameter and multiparameter pH instrument systems gt Nearly all problems encountered during pH calibration and measurement can be attributed directly to the condition and responsiveness of the pH electrode table 6 4 3 gt For any problem first test that the instrument batteries are fully charged Keep spare batteries on hand that are fully charged Table 6 4 3 Troubleshooting guide for pH measurement DIW deionized water Symptom Possible cause Corrective action Instrument system e Buffers may be contaminated or old Use fresh buffers un ae Faulty electrode Recondition or replace electrode see section 6 4 2 TOU Sees Weak batteries Replace with new or fully charged batteries Slow response For liquid filled electrodes Weak or incorrect solution Change filling solution to correct molarity No or low filling solution Add fresh solution of correct molarity Dirty tip for example visible chemical deposits or organic or biological matter on the electrode Rinse tip with DIW if residue persists use solution and cleaning method recommended b
52. a mean pH from logarithmic operations The effects of field conditions on the quality of field measurements water quality samples and data integrity must be anticipated by field personnel and protocols to minimize sample contamination as described in NFM 4 and 5 are to be implemented as standard operating procedure Chapter A6 Field Measurements pH Version 2 0 10 2008 pH 21 22 pH TECHNICAL NOTE The pH value of a given sample always is recorded in the USGS database as a median of a series of stable measurements For applications that require reporting pH over time for example an annual average pH or space however computation of the mean of the hydrogen ion activity may be useful To compute a series of pH measurements collected over time or space a Take the antilog of each pH measurement using the following equation Activity 10 9H b Add all the antilog values and divide the sum by the total number of values Convert the calculated mean activity back to pH units using the equation pH 10910 mean H activity If reporting pH as a computed mean document this information and the procedure used Do not enter a mean pH value in the USGS NWIS database under the parameter code for a median or direct determination of pH 6 4 4 A pH MEASUREMENT IN SURFACE WATER When using a single parameter pH electrode meter instrument system the pH of surface water is determined ex situ from a quiescent non stirre
53. at the centroid of flow e EWlI mean or median of all subsections measured Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 22 DO Ground water To determine the concentration of DO in an aquifer the water being measured must not contact air Study objectives and site characteristics will dictate the specific procedures selected If the DO concentration is less than 1 mg L refer to the spectrophotometric method sec tion 6 2 2 gt Throughout measurement use equipment that avoids aeration and operate equipment to mitigate losses or gains of dissolved gases Consult NFM 6 0 for proper downhole and flowthrough chamber sampling procedures gt Use a positive displacement submersible pump and high density plastic or fluorocarbon polymer sample tubing that is relatively gas impermeable if possible Use transparent materials for the tubing and chamber to allow checking for bubbles Air bubbles that adhere to the sides of the tubing and flowthrough chamber will add significant error to low level DO measurements A F White U S Geological Survey written commun 1993 Never use a bailed or other discrete sampler to determine the concentration of DO in ground water Follow the steps below to measure DO in ground water 1 Calibrate the DO instrument onsite Check that the thermistor ther mometer has been certified by the USGS Water Science Center within the past 4 months 2 In
54. bottles with deionized water from the beaker taking care to avoid introducing any air bubbles and overflowing the bottles adequately to remove any trapped air bubbles 6 Determine the DO concentration of the water in each BOD bottle as follows a Add one each of the following dry reagent pillow packets e alkaline iodide azide white powder e manganous sulfate pinkish colored powder b Recap the bottle Do not allow air bubbles to be trapped in the bottle c Invert the bottle 25 times or more to completely dissolve the reagents e An orange brown flocculent indicates the presence of DO e Allow the flocculent to settle halfway down the bottle approximately 5 minutes e Invert the bottle 25 times again let the flocculent settle again until the upper half of the solution is clear d Add one reagent pillow of sulfamic acid Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 32 DO e Recap the bottle without introducing air or air bubbles Invert the bottle 25 times until all of the flocculent and granules are dissolved leaving a yellow color f a clean 25 mL buret with 0 025 N Normal sodium thiosulfate titrant Remove any air bubbles from the delivery tube beneath the stopcock and zero the meniscus g Usea clean graduated cylinder to measure 200 mL of the sample and pour the sample into a clean wide mouth Erlenmeyer flask h Place the flask on a magnetic stirrer Add a cle
55. buffers experience these conditions their pH values can no longer be assumed to be valid Discard buffer solutions and any other reagents appropriately Before using buffers in the calibration sequence bring them to the temperature of the sample solution as much as possible Since buffer composition differs among manufacturers check the temperature correction factors provided by the manufacturer in order to assign the correct pH value to the buffer for the temperature of the buffer at the time of calibration Chapter A6 Field Measurements pH Version 2 0 10 2008 10 pH In order of greatest to least sensitivity of standard buffers to CO contamination pH 10 buffer gt pH 7 buffer gt pH 4 buffer In order of greatest to least variation of buffer pH with change in temperature pH 10 buffer gt pH 7 buffer gt pH 4 buffer 6 4 MAINTENANCE OF pH INSTRUMENTS Proper care of pH meters and particularly of the electrode is essential for maintaining the accuracy and precision required for pH measurements and promotes the longevity of the equipment pH instrument maintenance includes adhering to the manufacturer s instructions for the use and care of the instrument and routine use of appropriate electrode cleaning reconditioning and storage requirements As always follow the manufacturer s instructions for the specific type of electrode in use Electrode performance must be monitored before every water quality field trip a
56. distributed to each participating laboratory and USGS Offices in each state 30 X PERFORMANCE AND SYSTEM AUDITS Project reviews are conducted quarterly by USGS staff and periodically by the USGS Area Water Quality Specialist USGS technical reviews are conducted periodically at the request of the principal investigator A Water Science Center Water Quality Review is held every three years by the USGS Regional Water Quality Specialist and Regional Staff Field methods are observed for consistency with national USGS procedures and the Center water quality data base is examined for agreement between laboratory and field data The project officer and other staff from VDEQ are kept informed of the status of the project on a quarterly basis by the development of a quarterly report detailing the number of samples collected per site and any problems associated with sampling or analysis VDCLS and the USGS Kentucky Sediment Laboratory participate in the Standard Reference Sample quality assurance program that analyzes the laboratory s performance as described previously 31 XI PREVENTIVE MAINTENANCE Preventive maintenance of field instruments is done on a routine basis to ensure that the instruments remain in good working order All potentially fragile electrodes and cells are stored in such a manner as to prevent breakage Additionally they are kept clean and free from any build up that may affect their performance rejuvenation of elec
57. ecce eee 19 6 4 3 C Calibration for high ionic strength water ee eee eee ee eee eene eene 20 6 4 3 D Calibration for the pH sensor in multiparameter instruments 21 6 4 4 Measurement tuas etna sonas etes stessa esas etes seen ases sse ea sess stones 21 6 4 4 4 pH measurement in surface 1 1 22 6 4 4 pH measurement in ground water eee ee eese eese e eene eee tne esee t taste ttaae 24 6 4 5 Troubleshooting eee eere ebenso sao 27 6 4 6 EE PER ote auae oe e koe EE VE 28 6 4 7 Selected references 28 6 4 8 30 Chapter A6 Field Measurements pH Version 2 0 10 2008 Illustrations 6 4 1 Diagram of a combination pH electrode neon aseo 6 6 4 2 Photographs of A a flowthrough cell chamber for use with single parameter field measurement sensors and B a flowthrough cell attached to a multiparameter Roo ense espe ee e Spe Sepe 25 6 4 3 Diagram showing use of a dual valv
58. field personnel Field blanks are collected by processing an analyte free water through sampling equipment at the field site Periodically standard reference samples are submitted to VDCLS and the USGS Kentucky Sediment Laboratory in order to check analytical results against a known standard This allows for determination of the accuracy of each laboratory and the presence of any bias Sources of reference samples may be either the Environmental Protection Agency or a commercial laboratory Completeness is assessed by comparing the number of base flow and stormflow samples completed with those scheduled reasons for any discrepancies are well documented 33 XIII CORRECTIVE ACTION FOR OUT OF CONTROL SITUATIONS Out of control situations may occur in the field or in the laboratory as a result of equipment breakdown despite careful planning and attention to procedures The primary methods for correcting out of control situations in the field are 1 repairing recalibrating or adjusting the malfunctioning instruments or 2 substituting an alternative piece of equipment Notes are made in the field log books and on the sampling field sheet when out of control situations occur In most instances no data are lost due to malfunctioning field equipment Potential out of control situations occurring in the laboratory may be identified by determining constituent concentrations that do not follow established concentration discharge patterns
59. forms e Reportthe median value of the final five measurements as the sample conductivity e If values exceed the stability criterion report the range of val ues observed for the time interval along with the median of the final five or more values Subsample measurement Conductivity measurements reported from bailed or other discrete samples need to be identified in the data base indicating the sampling method used Refer to 6 0 3 B in NFM 6 0 for use of bailers and the subsample method 1 Calibrate the conductivity instrument system onsite e Bring standard solutions to the temperature of the water to be sampled by suspending the standards in a bucket into which well water is flowing Allow at least 15 minutes for tempera ture equilibration Do not contaminate standards with sample water a Check the temperature of the water flowing into the bucket against that of standards b Check that the thermometer usually a thermistor function in the conductivity meter has been certified within the past 4 months for the temperature range to be measured e After calibration rinse the conductivity and temperature sen sors thoroughly with deionized water Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 19 2 Draw off subsamples for measurement e Quality control Collect three subsamples to check pre cision e If samples need to be stored for a short time or if several
60. http www icllabs com pdfs GMP 201 1 20Mar 202003 pdf ICL Calibration Laboratories Inc 2005 accessed December 16 2005 at http www icllabs com Lab Safety Supply 2005 accessed December 16 2005 at https www labsafety com calibration Stevens H H Jr Ficke and Smoot 1975 Water temperature influential factors field measurement and data presentation U S Geological Survey Techniques of Water Resources Investigations book 1 chap D1 65 p Thermometrics 2005 Thermometrics What is a thermistor accessed December 16 2005 at http www thermometrics com htmldocs whatis htm Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 21 U S Geological Survey variously dated National field manual for the collection of water quality data U S Geological Survey Techniques of Water Resources Investigations book 9 chaps 1 9 available online at http pubs water usgs gov twri9A Wagner R J Boulger R W Jr Oblinger C J and Smith B A 2006 Guidelines and standard procedures for continuous water quality monitors station operation record computation and data reporting U S Geological Survey Techniques and Methods book 1 chap D3 Ween Sidney 1968 Care and use of liquid in glass laboratory thermometers Transactions of Instrument Society of America v 7 no 2 p 93 100 Wood W W 1976 Guidelines for collection and field analysis of ground water sample
61. in the basin and expansion of the Washington D C suburbs may increasingly affect the water quality of the river by causing elevated sediment concentrations in runoff and an increase in concentrations of nutrients associated with the sediment such as total phosphorus The average discharge at this station is 1 660 2 5 computed during a period of 86 years Prugh and others 1994 The location of the current sampling station and gage in Spotsylvania County Va is lat 38 18 30 long 7723146 NAD83 In 2004 one additional water quality monitoring station was added in the Rappahannock River basin This new station is the Rapidan River near Culpeper Va USGS station 01667500 and VDEQ station 3 030 21 The drainage area for this watershed is 472 mi The location of this monitoring site is lat 3822101 long 77258730 NAD83 which is at State Highway 522 The Appomattox River Basin is within the James River basin but because the Appomattox River enters the James River below the Fall Line it is not included as a source to the James River monitoring station at Cartersville and so is monitored separately The basin area above the confluence with the James is 1 600 mi approximately 16 percent of the James River basin and 4 percent of the area of Virginia The Appomattox River basin begins in the Piedmont physiographic province and flows through a small portion of the Coastal Plain before it flows into the James River near Hopewell The
62. instruments only e Ifthe water velocity at the point of measurement is less than about 1 ft s use a stirring device or stir by hand to increase the velocity To hand stir raise and lower the sensor at a rate of about 1 ft s but do not break the surface of the water The stir by hand method may not be appropriate in lakes reservoirs or slow moving waters for example bayous as these water bod ies may be stratified at the point of measurement making accu rate DO measurements impossible This could be especially problematic in areas where DO concentrations change substan tially over short distances such as near the thermocline or bot tom sediments e High stream velocity can cause erroneous DO measurements 4 Record the temperature without removing the sensor from the water 5 After the instrument reading has stabilized record the median DO concentration see NFM 6 0 e The reading should stabilize to within 0 2 mg L 6 For EWI EDI or multiple vertical measurements proceed to the next station in the cross section and repeat steps 3 through 5 When measurements for the stream have been completed remove the sensor from the water rinse it with deionized water and store it according to the manufacturer s instructions 7 Record DO concentrations on the field forms e Instill water median of three or more sequential values e EDI mean value of all subsections measured use the median if measuring one vertical
63. key personnel and directs the efforts to organize describe and interpret the results of the monitoring Has ultimate responsibility for quality assurance FIELD SAMPLING Hydrologic Technician s U S Geological Survey Richmond VA Other Hydrologists and Hydrologic Technicians as needed Coordinate all field activities of the program including procuring all necessary equipment collecting water samples according to the USGS sampling protocol measuring field parameters and coordinating all field quality assurance data collection 18 LABORATORY ANALYSIS Virginia Division of Consolidated Laboratories VDCLS Richmond VA Jay Armstrong Nutrients Chris Morton Solids Bailey Davis Carbon and Chlorophyll A Complete laboratory analyses on a timely basis and return analytical results to VDEQ CBO Provide assistance with information concerning analytical techniques for constituents USGS National Water Quality Laboratory NWQL Denver CO John Vasquez Supervisory Chemist Nutrients Harold Ardourel Supervisory Chemist Solids Provides standard reference samples to VDCLS USGS Kentucky Sediment Laboratory Aimee Downs Geographer Provides suspended sediment data for the primary RIM stations DATA MANAGEMENT Hydrologist s U S Geological Survey Richmond VA Hydrologic Technician U S Geological Survey Richmond VA Cindy Johnson Virginia Department of Environmental Quality Richmond VA Responsible for ma
64. lt 0670 92670 06670 76670 86670 076 94870 08870 8870 78870 716870 46870 66870 60670 20670 670 17670 817670 20670 920670 06670 46670 216670 078 44870 6L8 0 8870 78870 16870 6870 86870 20670 90670 01670 1670 81670 20670 42670 60670 lt lt 6670 274670 074 71870 8 870 058870 98870 06870 6870 86870 20670 40670 60670 lt 1670 421670 12670 42670 60670 lt 6670 96670 079 64870 4870 88 0 48870 68870 6870 76870 70670 40670 60670 lt 1670 21670 00670 0670 80670 056670 96670 074 04870 9870 08870 78870 88870 06870 96870 00670 0670 80670 21670 91670 00670 0670 80670 056670 46670 07 14870 4 870 6 870 8870 8870 76870 46870 66870 60670 20670 670 51670 61670 26 O0 12670 716670 46670 ove 14870 SL8 0 648 0 88 0 L88 0 76870 46870 66870 06 0 70670 II6 0 51670 61670 26 0 70670 76670 46670 o z 04870 TvL8 O 8 870 08870 98870 06870 v68 0 86870 20670 90670 01670 1670 81670 22670 92670 06670 EEO 69870 8 0 44870 T88 0 48870 68870 lt 6870 68 0 70670 40670 01670 17670 81670 20670 90670 06670 6670 070 00066 000026 00076 00006 00062 00080 00045 000902 00040 000702 00062 000022 00070 00000 0006 0008 00071 2o sz ur AQTATIONpUOD penunuo5 AiAn2npuoo uo peseq 1 10 s10326j uonoa402 9 U S Geological Survey TWRI Book 9 Dissolved Oxygen Version 2 1 6 2
65. many similarities each river has unique basin flow and water quality characteristics The Pamunkey and Mattaponi River basins are monitored above their confluence to form the York and are reported separately for this study The total area of the Pamunkey River Basin is 1 474 mi or about 4 percent of Virginia The Pamunkey River basin begins in the lower part of the Piedmont Province where the relief is relatively low and extends into the Coastal Plain The basin contains expanses of forested wetlands and marshes that are significant sources of wildlife productivity Virginia Water Control Board 1988 Ashland and Mechanicsville are the two major towns in the basin 11 The Pamunkey River basin monitoring station USGS station 01673000 and VDEQ station TF4 1 VDEQ Discontinued 3 2001 1s located near Hanover Va The area of the drainage basin above the sampling station is approximately 1 081 mi which is about 40 percent of the York River basin The low relief and relatively wide basin tend to produce stormflow peaks that are slow to peak and to recede There is some regulation of the Pamunkey River from the dam at Lake Anna approximately 100 mi upstream of the monitoring station on the North Anna River The average discharge at this station is 1 110 ft s computed during a period of 21 years Prugh and others 1994 The location of the site in Hanover County Va is lat 37 46 04 long 77 19 56 NAD83 In 2007 one additional w
66. millivolt data in the pH meter electrode logbook e Press Cal or other display instructions to lock in the pH 7 calibration TECHNICAL NOTE During the calibration sequence after the DIW and buffer rinses and when the specific buffer value is ready to be locked in to the calibration some meters provide the opportunity to adjust the initially displayed pH value to a corrected pH value for that buffer solution If this adjustment is equal to or less than 0 05 pH units proceed with the adjustment but specifically note this in the pH meter electrode logbook If the adjustment would exceed 0 05 pH units the pH electrode is not functioning optimally consider reconditioning the electrode or using another electrode until the cause of the substandard performance can be determined Chapter A6 Field Measurements pH Version 2 0 10 2008 18 pH 8 10 Return to step 6 above followed by step 7 repeating each of the procedures just followed but using either the pH 4 or pH 10 buffer whichever buffer solution along with the pH 7 buffer brackets the pH values of the environmental water to be sampled Record all the calibration data including the millivolt data in the pH meter electrode logbook see step 7 to test the adequacy of the calibration using the slope test or millivolt test At this point the electrode should be calibrated Check the adequacy of the calibration and that the electrode is functioning properly
67. nontradi tional pH measurement method must be entered under the unique parameter and or method code designated in the USGS National Water Information System NWIS water quality database pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 CALIBRATION FOR THE pH SENSOR IN 6 4 3 D MULTIPARAMETER INSTRUMENTS Before beginning calibration of the pH electrode in a multiparameter instrument sonde read and follow carefully the instrument manual and manufacturer s instructions Guidelines that incorporate USGS protocols for pH calibration and measurement are described in NFM 6 8 General procedures for calibration of the pH sensor in a multiparameter sonde 1 Select the pH 7 and one additional buffer solution that will bracket the anticipated pH of the sample Equilibrate the temperature of the buffers to the temperature of the environmental sample 2 Rinse the sonde and electrode thoroughly three times with DIW before and between use of each buffer solution 3 Rinse the pH and temperature sensors three times with separate aliquots of the first pH buffer using the pour swirl discard pour sit discard pour sit measure method described in section 6 4 3 A Allow enough time for the sensors to equilibrate to buffer temperature before locking in the first calibration point 4 Repeat step 3 using the second pH buffer and lock in the second calibration point Depending on site conditions and study objectives it might be
68. objectives during calibration Properly working electrodes should give 95 to 102 percent response of that expected from the theoretical Nernst relationship Busenberg and Plummer 1987 TECHNICAL NOTE The theoretical Nernst response is 59 16 mV pH unit at 25 C but varies based on temperature Adequate adjustment of the Nernstian relation requires manual or automatic temperature compensation ATC Most modern pH meters have the ATC feature A slope of 95 percent or less signals probable electrode deterioration and the need to monitor closely any further decline in slope percent Consider replacing the electrode if calibration slope values cannot be brought to greater than 95 percent Do not use an electrode with a slope of less than 95 percent 5 Keep the electrode bulb moist and capped when not in use Use only the wetting solution recommended by the manufacturer For routine cleaning of the pH electrode Keeping electrodes clean and the liquid junction free flowing is necessary for producing accurate pH measurements Because of the variety of electrodes available check the manufacturer s instructions for specific tips and precautions 1 Before and after each use rinse the electrode body thoroughly using only DIW Dispense the DIW from a squeeze bottle 2 Do not wipe or wick moisture from electrodes with paper towels or ChemWipes as these can scratch the pH glass membrane Wiping the electrode body with paper also may cause a static
69. of oxygen in water decreases as salinity increases Correction factors for salinity normally are applied after measuring DO Information about oxygen solubility and salinity and a salinity correction factors table are in section 6 2 5 Interactive tables also are available according to user specified temperature pressure and salinity at http water usgs gov software dotables html accessed Apr 27 2006 Surface water Standard determinations of dissolved oxygen in surface water represent the cross sectional median or mean concentration of dissolved oxygen at the time of observation Measuring the DO concentration at one distinct spot in a cross section is valid only for flowing water with a cross sectional DO variation of less than 0 5 mg L Discerning such variation requires cursory cross section measurement The effort involved in collecting this cross section information is only slightly less than making an equal width increment EWI equal discharge increment EDI or multiple vertical cross sectional measurement Measurements made at multiple locations in the cross section are recommended when possible Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 20 DO Determining DO for a single vertical at the centroid of flow at the midpoint of the vertical only represents the cross section under ideal mixing conditions gt Do not measure DO in or directly below sections with turbulent flow
70. or that seem out of range The primary method of correcting out of control situations at VDCLS is to first re examine the paperwork for clerical or translation errors such as an incorrect date or station The next step would be to examine the field paperwork to look for any written Observations of problems at the site Finally if the source of the questionable value could not be discerned the next step is to contact the laboratory to ask for confirmation of that concentration and to ask for any bench observations that might influence the sample concentrations Based on the result of any of these steps any mismatched site information and data would be corrected if possible No data are ever changed unless there is a logical fact based reason for doing so Any changes and the rationale for the changes are clearly documented on the Field Sheet and initialed by the Project Chief or a senior project person XIV QA REPORTING PROCEDURES samples collected will be analyzed at VDCLS in Richmond VA VDCLS performance will be evaluated through the use of duplicate and standard reference samples Results of the laboratory s performance will be evaluated annually 34 Selected References Clesceri L S Greenberg A E and Trussell R R eds 1989 Standard methods for the examination and treatment of water and wastewater 17th ed Washington D C p 2 18 5 82 Cohn T A Delong L L Gilroy E J Hirsch R M and Wells D K 1989 Es
71. pH gt Temperature affects the chemical equilibria of ionic activities in aqueous solutions including that of H Hem 1989 For example neutral pH for pure water at 30 is calculated to be 6 92 whereas at 0 C neutral pH is 7 48 The pH of pure water at 25 C is defined as 7 00 Therefore the temperature of the solution must be taken into account when measuring and recording pH TECHNICAL NOTE Although pH commonly is reported on a scale ranging from 0 to 14 pH values of less than 0 can be measured in highly acidic solutions and pH values greater than 14 can be measured in concentrated base solutions Nordstrom and Alpers 1999 Hem 1989 6 4 1 EQUIPMENT AND SUPPLIES The instrument system that is used to measure pH consists of a pH meter sensor s a pH electrode and often a temperature sensor and buffer solutions table 6 4 1 Since a variety of instrument systems are available from manufacturers multiparameter instruments for example are described in 6 8 the procedures described in this section may not be applicable or may need to be modified depending on the specific instrument system being used Field personnel should gt thoroughly familiar with the information provided in the manufacturer s user manual gt Adhere to USGS protocols for quality control and assurance of pH measurements P Test the meter and electrode before each field trip Temperature affects the operation of pH meters elect
72. per minute for sample collection Continue pumping the well and allow the sample tube to overflow during sample collection e Use optically clear materials for the tubing and chamber to check that entrained bubbles are not present Air bub bles that adhere to the sides of the tubing and flowthrough chamber will add significant error to low level DO mea surements A F White U S Geological Survey written commun 1993 e Flush air bubbles from the tubing walls and flowthrough chamber Tap the tubing with the blunt end of a tool to dis lodge entrained air bubbles Insert the glass ampoule tip first into the overflowing sampler tube so that the tapered tip is at the bottom of the tube Snap the tip by gently pressing the upper end of the ampoule toward the wall of the sampling tube The ampoule will fill leaving a bubble to facilitate mixing Mix the contents of the ampoule by inverting it several times allowing the bubble to travel from end to end Wipe all liquid from the exterior of the ampoule using a lint free tissue U S Geological Survey TWRI Book 9 DO 29 5 Insert the ampoule directly into the 13 mm diameter spectropho tometer cell holder immediately after retrieval 6 Read absorbance e Make spectrophometer readings as soon as possible after snap ping the tip of the ampoule optimally within 30 seconds e Read each DO value three times and record the median value 7 Calculate the
73. place sample into the cell holder and close the light shield Record this reading in AU or FAU Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 47 QUALITY ASSURANCE 6 7 4 PROCEDURES Quality assurance procedures should be developed in accordance with the objectives of the sampling or monitoring plan The primary emphasis should be on quantifying the sources of variability and bias in turbidity measurements that can affect the utility of the data being collected Where turbidity from one water source will be compared with turbidity from another source or against a numerical criterion the use of consistent procedures instrumentation and supplies is critical VARIABILITY 6 7 4 Sources of variability include the different instruments in use even similar models differing subsampling techniques different operators spatial and temporal variations in the water body being measured and different sampling procedures being used The data resulting from static turbidity determinations also can be negatively biased from particle settling Variability in turbidity can be quantified through repeated measurements of turbidity at different times using different instrumentation or using different methods In some cases it might be useful to compare results of a field turbidity measurement with that of a laboratory analyzed sample Keep in mind however that sample properties that affect turbidity can degrade d
74. published data First gt Take a cross sectional conductivity profile to determine the degree of system variability A submersible sensor works best for this purpose Refer to NFM 6 0 for criteria to help decide which sampling method to use Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 13 Next follow the 7 steps listed below 1 Calibrate the conductivity instrument system at the field site after equilibrating the buffers with stream temperature 2 Record the conductivity variation from a cross sectional profile on a field form and select the sampling method e Flowing shallow stream wade to the location s where ductivity is to be measured e Stream too deep or swift to wade lower a weighted conduc tivity sensor from a bridge cableway or boat Do not attach weight to the sensor or the sensor cable e Still water conditions measure conductivity at multiple depths at several points in the cross section 3 Immerse the conductivity and temperature sensors in the water to the correct depth and hold there no less than 60 seconds until the sensors equilibrate to water conditions 4 Record the conductivity and corresponding temperature readings without removing the sensors from the water e Values should stabilize quickly to within 5 percent at conduc tivity lt 100 uS cm and within 3 percent at conductivity 2100 uS cm e Record the median of
75. should be avoided for the following reasons Placing the pH electrode directly into the borehole risks damage to the delicate glass membrane scratching pitting coating which will inhibit the correct functioning of the electrode Any accretions or coatings on the inside of the borehole may be transferred to the pH sensor and damage or alter the membrane gt Pumps wiring and or other equipment within the borehole may damage or degrade the pH sensor and the sonde gt Any static electrical charge on the inside of the well casing or borehole may be transferred to the pH electrode a condition sometimes referred to as a ground loop which also compromises accurate pH measurement Always measure and record sample temperature concurrently with pH measurements pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 25 Figure 6 4 2 Photographs of A a flowthrough cell chamber for use with single parameter field measurement sensors shown without sensors installed and B a flowthrough cell attached to a multiparameter sonde Photograph A courtesy of Geotech Environmental Photograph B is a USGS stock image Mr Both stopcocks Stopcocks close open while the when bailer is raised bailer is lowered prevent mixing with to the intended water in the well above sampling interval the sample interval Figure 6 4 3 Use of a dual valve double stop cock Teflon bai
76. store sensors clean and dry Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 7 CALIBRATION 6 3 2 Conductivity systems must be calibrated before every water qual ity field trip and again at each site before samples are measured Calibration readings are recorded in the instrument log book and on field forms at the time the instrument is calibrated Remember the temperature sensor on the conductivity sensor must be District certified within the past 4 months Calibration and operating procedures differ depending on instrument and sensor type gt Some conductivity sensors may need to be soaked overnight in deionized water before use Check the manufacturer s instructions gt Some analog instruments require an initial mechanical zero adjustment of the indicator needle Foracup type cell calibration and measurement procedures described for the dip type cell apply the only difference is that standards are poured directly into the cup type cell Whenusing a dip type cell do not let the cell rest on the bottom or sides of the measuring container Calibrate at your field site bring standards to sample temperature Conductivity systems normally are calibrated with at least two standards Calibrate sensors against a standard that approximates sample conductivity and use the second standard as a calibration check The general procedures described in
77. the specific instrument to be used Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 10 DO 6 2 1 8 CALIBRATION Instrument systems for the amperometric or the luminescent sensor methods must be properly calibrated and tested before each field trip and cleaned in the field after each use gt Amperometric instruments Different manufacturers recommend different calibration frequencies for membrane electrode DO meters however virtually all state that optimum instrument performance and data quality will be obtained by frequent calibration Calibration and operation procedures for the amperometric method differ among instrument types and makes refer to the manufacturer s instructions Luminescent sensor instruments Luminescent based sensors are precalibrated by the manufacturer and most manufacturers literature suggests that no further calibration is warranted The accuracy of factory calibrations however may not satisfy the data quality objectives of a specific program Frequency of calibration can have a significant effect on the overall accuracy and precision of DO measurements therefore users of these meters are advised to make frequent calibration checks and to recalibrate as frequently as required to meet specific data quality objectives One point and two point calibrations Calibration for most amperometric DO instruments and some lumines cent sensor instruments can only be checked w
78. useful to check the calibration range of the pH sensor using a third buffer if appropriate lock in a value 5 Always record temperature information with calibration information in the pH meter electrode logbook and on the field sheet MEASUREMENT 6 4 4 The pH of sample water is to be measured as soon as possible after removal of the sample from its environmental source The pH of a water sample can change substantially within hours or even minutes after sample collection as a result of temperature change degassing loss of sample oxygen carbon dioxide hydrogen sulfide ammonia in gassing gain of sample oxygen carbon dioxide hydrogen sulfide ammonia mineral precipitation formation of calcium carbonate iron hydroxides metabolic respiration by microorganisms and other chemical physical and biological reactions Hem 1989 Field conditions including rain wind cold dust direct sunlight and direct exposure to vehicle exhaust can cause measurement problems Always protect the instrument system and the measurement process from the effects of harsh weather and transportation damage The pH value of an aqueous system should be determined by taking the median of three or more separate and stable measurements that are recorded in a quiescent sample Recording a median value ensures that the reported pH value represents a true measurement instead of a computed measurement and avoids the mathematical procedure required to compute
79. using the slope test or and the millivolt test Some instruments have the capability to display the slope value this datum should be recorded in the pH meter electrode logbook The slope test Values ranging from 95 to 102 percent slope are acceptable if the slope percent value is outside of this range clean the electrode and check the level of the filling solution that the fill hole is open and that the junction is free flowing then recalibrate TECHNICAL NOTE Since the theoretical Nernstian relation between electrical response and pH at the calibration temperature is programmed into the pH meter software the calibration process provides the Nernstian response from the electrode meter system being calibrated The actual calibration slope is calculated and the displayed slope value represents the actual slope of the electrical potential millivolt pH line that this calibration has produced The millivolt test For pH meters that display and store only millivolt readings do not dis play the slope percent use the following guidelines to ascertain adequate calibration pH 7 buffer Displays between 10 to 10 mV pH buffer Displays between 165 to 195 mV pH 10 buffer Displays between 165 to 195 mV fusing buffers other than the standard pH 4 7 and 10 buffers refer to the information pro vided with the specific buffer lot to determine the correct temperature compensated milli volt potential for that
80. vVTvV8 O 89870 04870 94870 09870 9870 89870 07 0870 70870 II8 0 SI8 0 61870 0870 70870 TESO 46870 66870 78 0 870 14870 44870 64870 69870 79870 076 70870 4508 0 60870 8 0 8 8 0 208 0 92870 06870 80 86870 7870 98 70 04870 48 0 84870 29870 79870 07 0080 v08 0 80870 218 0 9IS8 0 12870 42870 628 0 8 0 LE8 O0O IV8 O 978 0 6v8 0 58 0 4870 29870 99870 66 70 08 0 270870 II8 0 ST8 O 618 0 8 0 828 0 26870 9 8 0 0870 vTS O 8 87 0 248 0 95870 79870 49870 070 00006 0006 00087 00047 0009 00057 00077 0006 0002 0001 0000 00066 00086 000 6 00096 00046 00076 Do sz sueuersodoru ur due uo peseq peAJossip 10 1010 UODO 7 7 9 4 1 Chapter A6 Field Measurements DO 44 7170 414470 I8L O v8L O 88 70 I6L 0 S6L O 86 70 52050870 40870 60870 ZT8 O 9I8 0 00870 0870 270870 06870 0760 2 1470 944270 64170 870 98 70 06 70 6470 16 70 10870 0870 80870 TT8 O0 4 870 817870 220870 420870 62870 0782 TLL 0 4270 84170 ISL O 48 70 68 70 26470 96 70 66 70 60870 90870 01870 7870 LT8 O 712870 0870 82870 07 2 69 70 4470 94170 08470 8 70 18 70 TOLO v6L O 86 70 20870 40870 60870 2 8 0 91870 02870 0870 72870 0790 89 70 TLL O 44 70 GLEO 288170 98 70 68470 lt 6 70 16 70 00870 0870 80870 II8 0 417870 8 870 220870 92870 0742 9970 04470 vL
81. which they are not designed can introduce significant errors All evidence indicates that formazin and stabilized formazin are safe to use as primary turbidity standards when good laboratory practices are followed Sadar and others 1998 Standard safety procedures including wearing laboratory coats glasses and gloves are considered adequate protection for routine use of formazin The primary hazard from the formazin solution is physical irritation Of the components in formazin only formaldehyde will evaporate and 3The use of brand names in this report is for example purposes only and does not constitute an endorsement by the U S Geological Survey Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 23 cause exposure through the air however its concentration in this mixture is well below what is considered to be a health risk Concentrations in formazin solutions diluted below 4 000 turbidity units will result in exposures that are reduced even further For more information see the Material Safety Data Sheet http www ilpi com msds index html Internet or Sadar and others 1998 TECHNICAL NOTE 5 The raw materials used in the synthesis of scratch formazin do present potential safety concerns These materials specifically hydrazine sulfate and hexamethylenetetramine hexamine are currently 2004 listed as a suspected carcinogen and an experimental mutagen respectively Hydrazine sulfate al
82. within the cross section that is representative Upon installation the meter will be connected to telemetry equipment that communicates the sensor data back to a central office location Through this telemetry the data can be observed and reviewed in real time e During the first year of the study manual samples will be collected over a large range of flow conditions and analyzed for suspended sediment concentrations e Site specific regression equations will be developed to relate turbidity values and suspended sediment concentrations over this large range of flow conditions e The site specific regression equations will be used to predict continuous suspended sediment concentrations from the continuous turbidity data Using the unexplained variance from the regression equation we can quantify the uncertainty in the suspended sediment predictions e The continuous suspended sediment concentrations and the continuous discharge record will then be used to predict continuous sediment loadings from each river to the Chesapeake Bay These predicted sediment loadings will be compared to sediment load estimates from other existing methods e g ESTIMATOR Differences between the methodologies will be documented and evaluated This approach is completely analogous to the standard methods for developing a continuous record of discharge in which stream stage water level is recorded over time a rating curve is developed for the station and the ratin
83. 006 DO 43 Dissolved Oxygen Version 2 1 6 2006 7 8 0 46870 870 vvT8 0 878 0 14870 vS8 0 84870 79870 49870 898 0 2 870 SL8 0 6 870 08870 98870 68870 0762 06870 96870 66870 78 0 97870 048 0 lt 48 0 LS8 0 09870 9870 79870 8 0 vLS8 O 8L8 0 8870 48870 88870 0780 8 0 46870 86870 27870 47870 678 0 4870 94870 09870 98 0 79870 048 0 870 4 870 08870 78870 L88 0 07 2 068 0 vt8 0 6870 IT8 O 778 0 8 8 0 248 0 54870 64870 29870 99870 69870 lt 870 9L8 0 08870 68870 78870 0790 628 0 870 96870 07870 7870 870 14870 4870 84870 19870 49870 89870 20 870 SL8 0 6 870 28870 98870 0742 80870 06870 46870 66870 27870 9 870 04870 64870 LESTO 09870 9870 79870 870 870 8 870 28870 48870 07 2 105870 06870 8 0 86870 TISO 978 0 6 8 0 24870 94870 64870 98 0 99870 048 0 870 LL8 O 88 0 78870 0 55 902870 60870 8 O0 6870 078 0 7 8 0 8 870 TS8 0 SS8 0 898 0 98 0 99870 69870 EL8 0 9 870 08870 78870 0722 40870 80870 06870 96870 66870 EPO 97870 04870 vS98 0 LS8 0 79870 49870 89870 CL8 O 9 870 6L8 0 lt 8870 0 IC 870 10870 IE8 0 vE8 0 86870 29870 69870 678 0 64870 96870 098 0 9870 1 98 0 870 SL8 0 8 8 0 28870 0702 005870 90870 06870 66870 16870 8 0 7 80 87870 04870 44870 64870 lt 9870 279870 OL8 0 870 LL8 O 78870 0 6T 28 0 40870 60870 256870 9E8 O0O OPEO ETVS8 O 870 IS8 0 998 0 85870 29870 99870 69870 48 0 LL8 O 08870 078 002870 vC8 0 10870 870 46870 66870 7870 97870 04870 4870
84. 176 Sadar M J 1998 Turbidity science Loveland CO Hach Company Technical Information Series Booklet No 11 26 p accessed March 25 2004 at http www hach com fmmimghach CODE L7061549 1 Sadar M Foster A Gustafson D and Schlegel J 1998 Safety of formazin and StablCal stabilized formazin as primary turbidity standards Loveland Co Hach Company Technical Notes 10 p accessed May 21 2003 at http www hach com fmmimghach CODE L14561511 1 Strausberg S I 1983 Turbidity interferes with accuracy in heavy metal concentrations Industrial Wastes v 29 no 2 p 16 21 Sutherland T F Lane P M Amos C L Downing J 2000 The calibration of optical backscatter sensors for suspended sediment of varying darkness levels Marine Geology v 162 p 587 597 Uhrich M A and Bragg H M 2003 Monitoring instream turbidity to estimate continuous suspended sediment loads and yields and clay water volumes in the upper North Santiam River Basin Oregon 1998 2000 U S Geological Survey Water Resources Investigations Report 03 4098 43 p U S Environmental Protection Agency 1993 Methods for the determination of inorganic substances in environmental samples Cincinatti Ohio U S Environmental Protection Agency EPA 600 R 93 100 178 p U S Environmental Protection Agency 1999 Guidance manual for compliance with the Interim Enhanced Surface Water Treatment Rule Turbidity provisions Washin
85. 3 to 5 minutes or more are within 0 2 mg L For each reading monitor fluctuations for 30 to 60 seconds and record the median value if necessary If the 0 2 mg L criterion is not met increase the purge period in accordance with study objectives and continue to record measurements at reg ularly spaced time intervals 6 Report sample DO as the median of the final five DO readings recorded Record on field forms any difficulty with stabilization 7 Remove the sensor from the water and rinse it with deionized water TECHNICAL NOTE Anomalously high DO measurements commonly are caused by aeration of ground water during pumping This can result from air leakage through loose fittings on production well pumps for example turbine pumps and also if drawdown in the aquifer introduces air into the cone of depression or through well screen perforations To avoid these problems review information about the pump well construction and drawdown data and previous data records A F White U S Geological Survey written commun 1993 Air bubbles in the lines and flowthrough chamber can add substantial error to low DO readings Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 24 DO 6 2 1 D TROUBLESHOOTING AMPEROMETRIC INSTRUMENTS The troubleshooting suggestions given in table 6 2 3 are for ampero metric instruments and are not exhaustive consult the manufacturer of your amperometric instrument f
86. 5 2004 at http ks water usgs gov Kansas pubs reports wrir 00 4 1 26 html Davies Colley R J and Smith D G 2001 Turbidity suspended sediment and water clarity A review Journal of the American Water Resources Association v 37 no 5 p 1085 1101 Gray J R and Glysson G D 2003 Proceedings of the federal interagency workshop on turbidity and other sediment surrogates April 30 May 2 2002 Reno Nevada U S Geological Survey Circular 1250 56 p accessed March 25 2004 at http water usgs gov pubs circ 2003 circ1250 Great Lakes Instrument Company undated Technical Bulletin Number T1 Turbidity Measurement Rev 2 193 Loveland Gschwend P M Backhus D A MacFarlane J K and Page A L 1990 Mobilization of colloids in groundwater due to infiltration of water at a coal ash disposal site Journal of Contaminant Hydrology v 6 p 307 320 Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 54 TBY International Organization for Standardization 1999 Water quality determination of turbidity Geneva Switzerland International Organization for Standardization ISO 7027 10 p Nightingale H I and Bianchi W C 1977 Ground water turbidity resulting from artificial recharge Ground Water v 15 no 2 p 146 152 Puls R W and Powell R M 1992 Acquisition of representative ground water quality samples for metals Ground Water Monitoring Review v 12 no 3 p 167
87. 670 06670 76670 76670 0007 0742 1 670 14670 4670 74670 79670 9670 279670 670 670 44670 78670 8670 8670 06670 6670 76670 0007 0 vc amp 6 0 04670 4670 96 0 09670 9670 219670 IL6 0 vL6 0 LLe6e 0 08670 8670 48670 06670 v66 0 L66 0 0007 076 2 670 04670 64670 74670 09670 9670 29670 0 6 0 670 1670 08670 8670 78670 06670 lt 6670 16670 0007 0720 9 670 04670 4670 274670 09670 lt 9670 79670 0 670 6670 44670 08670 8670 8670 06670 66 0 76670 0007 HTG 97670 6v6 0 56 0 94670 09670 lt 9670 99670 0 6 0 46 0 LL6 0 08670 lt 8670 48670 06670 lt 6670 L66 0 0007 0702 487670 676 0 2054670 94670 64670 9670 99670 0 6 0 4670 9 670 08670 lt 8670 78670 06670 lt 6670 76670 0007 076 47670 6 670 2054670 94670 64670 lt 69670 99670 69670 46 0 9 670 08670 lt 8670 78670 06670 lt 6670 176670 0007 078 St6 0 8 670 24670 44670 64670 29670 99670 69670 46 0 94670 08670 8670 98670 06670 lt 6670 76670 0007 77670 8 67 0 714670 44670 84670 29670 99670 69670 24670 9 670 6670 8670 98670 06670 lt 6670 76670 0007 079 776 0 Lvw6 0 14670 44670 84670 29670 49670 69670 2670 9 670 64670 8670 98670 06670 lt 6670 76670 0007 O ST v6 0 Lv6 0 IS6 0 74670 856 0 19670 49670 69670 2 670 9 670 6 6 0 8670 98670 06670 lt 6670 276670 0007 07 v6 0 Lv6 0 04670 75670 84670 79670 459670 89670 2 670 44670 64670 8670 98670 06670 lt 6670 26670 0007 OEE v6 0 9 670 04670 4670 496 0 79670 49670 89
88. 670 ZL6 0 4 670 6L6 0 58670 98670 68670 amp 66 0 76670 0007 072 0 670 9 670 04670 ESEO 14670 79670 9670 89670 670 4 670 6 670 258670 98670 68670 66 0 96670 0007 O TTI 7670 9 670 6 670 lt 4670 LS6 0 09670 9670 89670 670 4 670 6L6 0 286 0 98670 68670 lt 6670 96670 0007 070 Tv6 0 976 0 6 670 64670 94670 09670 9670 29670 670 44670 84670 258670 98670 68670 66 0 96670 0007 076 670 4 670 6 670 24670 94670 09670 69670 79670 670 4 670 8 670 58670 98670 68670 lt 6670 96670 0007 078 6 0 776 0 8 670 24670 94670 64670 96 0 29670 670 4670 84670 258670 48670 68670 66 0 96670 0007 074 07670 vv6 0 8 670 24670 44670 64670 9670 79670 04670 670 8 670 058670 48670 68670 lt 6670 96670 0007 079 076 0 670 670 174670 44670 64670 lt 9670 99670 O46 0 670 84670 78670 48670 68670 lt 6670 96670 0007 074 66670 6 670 1 670 14670 44670 64670 29670 99670 0 670 PLEO 8 670 8670 48670 68670 lt 6670 96670 0007 07 66670 670 Lv6 0 174670 467 0 84670 29670 99670 04670 PLEO 14670 78670 48670 68670 66 0 96670 0007 076 86670 576 0 9 670 04670 4670 84670 29670 99670 04670 lt 670 14670 8670 48670 68670 256670 96670 0007 0 c 86670 6 0 9 670 04670 4670 84670 29670 49670 69670 46 0 14670 78670 68670 68670 26670 96670 0007 QE 86670 20 670 97670 04670 lt 4670 74670 79670 49670 69670 6670 14670 78670 48670 68670 26670 96670 0007 070 00097 0004 0007 0006 00027 000 0000
89. 7 4 gt The designations NTU NTRU BU AU and signify the use of a broad spectrum incident light in the wavelength range 400 680 nanometers nm gt The designations FNU FNRU FBU FNMU generally signify an incident light in the range between 780 900 nm These reporting units are equivalent when measuring a calibration solution for example formazin or polymer beads see section 6 7 2 but their respective instruments may not produce equivalent results for environmental samples Information for specific instruments is maintained at http water usgs gov owq turbidity codes xls The term turbidity unit as used in this manual refers generically to turbidity measured by instruments of undefined design Note that manufacturers might for the foreseeable future retain the general use of the measurement unit NTU when referring to calibrants and equipment TECHNICAL NOTE 2 Historically reporting units included Jackson Turbidity Units JTU and Formazin Turbidity Units FTU Neither unit is still in common use due to lack of precision JTU and lack of specificity about instrumentation type FTU 2150 7027 specifically defines the light source for FNU measurements as having a wavelength of 860 nm with a bandwidth of 60 nm The angle of the detector must be 90 degrees from incident light plus or minus 2 5 degrees Chapter A6 Field Measurements Turbidity Version 2 1 9 2005
90. 70 Ov6 O lt 670 0722 98870 06870 6870 76870 70670 0670 80670 670 lt 4 670 817670 20670 42670 60670 06670 96670 66670 lt 670 0772 98870 68870 68 0 96870 00670 60670 70670 II6 0 670 81670 12670 42670 80670 26670 46670 66670 2 670 0702 48870 88870 26870 96870 66870 0670 90670 01670 670 71670 12670 2670 80670 6 0 46670 86670 2 670 0 6T 78870 888 0 T68 0 46870 66870 200670 90670 60670 0 LI6 0 02670 2670 10670 6 670 v t6 O0O 86670 2 670 078 88 0 48870 16870 6870 86870 10670 40670 60670 21670 91670 0202670 lt 0670 404670 06670 6670 86670 670 0241 058870 98870 06870 68 0 76870 70670 06 0 80670 21670 41670 617670 26 0 90670 06670 EEO 16670 THEO 079 08870 48870 68870 lt 6870 96870 00670 0670 20670 670 41670 81670 22670 90670 602670 6670 16670 0 670 T88 0 v88 0 888 0 26870 96870 66870 lt 0670 20670 670 71670 81670 22670 40670 62670 0 96670 0 670 07 08870 8870 18870 76870 46870 66870 20670 90670 017670 71670 271670 72670 40670 80670 06670 968670 66670 64870 8870 L88 0 06870 6870 86870 20670 90670 60670 T6 O 71670 02670 0670 856 0 26670 46670 66670 O T 848 0 08870 988 0 068 0 6870 26870 710670 40670 60670 ZT6 O0 91670 02670 0670 20670 670 46670 66670 O TTI 14870 8870 48870 68870 lt 6870 26870 00670 0670 806 0 21670 91670 61670 lt 0670 20670 0 76670 86670 070 12870 08870 88 0 88870 26870 96870 00670 0670 20670 II6 0 41670 61670
91. 870 14870 44870 84870 29870 49870 89870 2 80 4 80 6 8 0 08870 48870 68870 26870 OEE 6870 0 8 0 870 8 0 14870 vS8 0 4870 719870 9870 89870 8 0 TvL8 O 8 870 18870 88 0 88870 716870 USTE 96870 66870 8 O0 9870 09870 64870 94870 09870 98 0 279870 48 0 4 870 08870 8870 L88 0 06870 TE 86870 86870 Zv98 0 978 0 678 0 cCS8 0 44870 64870 209870 99870 69870 E L8 0 9L8 0 6 8 0 8870 98870 06870 0706 00004 00067 00087 00047 0009 000457 00077 00057 00017 0000 00066 00086 0004 6 00096 00046 0007 2o SnrsTI9o aed ur KATATAONpuoD dw L 16870 00670 60670 90670 01670 T6 O 9I6 0 6 6 0 lt 2670 90670 60670 06670 46670 66670 2 670 4 670 8 670 0746 96870 66870 60670 90670 60670 21670 91670 617670 22670 40670 60670 06670 46670 86670 670 4 670 8 670 0 vt 86870 66870 20670 40670 80670 21670 SI6 0 8T6 0 20670 42670 80670 IE6 0 46670 8 670 670 670 Lv6 0O 07 lt 6 86870 86870 70670 40670 80670 670 717670 81670 72670 2670 80670 76670 6670 7670 670 670 LEO 0706 76870 16870 70670 0670 70670 670 670 271670 02670 2670 10670 06670 6670 1670 076 0 670 LEO 6870 96870 00670 06 0 20670 OI6 0 T6 O 4 16 0 00670 lt 0670 10670 06670 t 6 0 96670 076 0 lt 60 9 670 0706 00066 00026 00076 00006 00062 000802 00045 00092 000402 00072 00062 00020 00010 000002 00061 00081 000 2o SNTSTEeD
92. 98 384 27p USGS 1998 National Field Manual for the Collection of Water Quality Data Techniques of Water Resources Investigations Book 9 variously paginated Available on the internet http water usgs gov owq FieldManual index html USGS 2003 Quality Assurance Plan for Water Quality Activities in the Virginia District This QA Plan is electronically available at http va water usgs gov LOCAL QW_QAplan_2003 pdf Wagner R J Mattraw H C Ritz G F and Smith B A 2000 Guidelines and Standard Procedures For continuous Water quality Monitors Site Selection Field Operation Calibration Record Computation and Reporting U S Geological Survey Water Resources Investigations Report 00 4252 Available online at http pubs usgs gov wri wri004252 Walling D E 1977 Assessing the accuracy of suspended sediment rating curves for small basin Water Resources Research 13 531 538 Wolman M G and Miller J P 1960 Magnitude and frequency of forces in the geomorphic processes Journal of Geology v 68 p 54 74 10
93. Appomattox River basin is primarily rural although the cities of Petersburg Colonial Heights and Hopewell are within the basin downstream of the sampling station at Matoaca The drainage area of the Appomattox River basin above the sampling station at Matoaca USGS station 02041650 is approximately 1 344 mi The monitoring station is unique among the River Input Monitoring stations in that the flow is controlled by a dam at Lake Chesdin 2 8 miles upstream of the sampling station This tends to delay water level rise from storms so that the water level is very slow to rise and to fall in comparison to the other monitoring stations Downstream of Lake Chesdin the steep gradient due to the rapid elevation change and a streambed of rocks and boulders result in expanses of rapids between the dam and the sampling station The average discharge at this station is 1 384 ft s computed during a period of 23 years Prugh and others 1994 The location of the site in Chesterfield County is lat 37 13 31 long 77 28 31 NAD83 The total area of the York River Basin is approximately 2 650 mi about 6 5 percent of Virginia s total land area consisting of the Pamunkey River the Mattaponi River and the coastal area below the sampling stations Agriculture is an important component of the economy of the York River basin and the area is primarily rural Although the Pamunkey and Mattaponi Rivers are often collectively presented as the York and have
94. Approvals QUALITY ASSURANCE PROJECT PLAN for the Virginia River Input Monitoring Program Prepared by Kenneth E Hyer and Douglas L Moyer U S Geological Survey 1730 E Parham Road Richmond VA 23228 for Virginia Department of Environmental Quality Chesapeake Bay Office PO Box 1105 Richmond VA 23218 Effective June 15 2011 Kenneth E Hyer Project Manager USGS John D Jastram Quality Assurance Officer USGS Frederick A Hoffman Project Officer VDEQ Quality Assurance Officer VDEQ Project Officer US EPA Quality Assurance Officer US EPA Date Date Date Date Date Date QUALITY ASSURANCE PROJECT PLAN for the Virginia River Input Monitoring Program Prepared by Kenneth E Hyer and Douglas L Moyer U S Geological Survey for Virginia Department of Environmental Quality Chesapeake Bay Office Richmond VA updated June 2011 TABLE OF CONTENTS L PROJECT DESCRIPTION 4 II PROJECT ORGANIZATION AND RESPONSIBILITY 17 III QA OBJECTIVES AND CRITERIA 20 IV SAMPLING PROCEDURES 24 V SAMPLECUSTODY 25 VI CALIBRATION PROCEDURES AND FREQUENCY 26 VII ANALYTICAL PROCEDURES 27 VIII DATA REDUCTION VALIDATION AND REPORTING 28 IX INTERNAL QC CHECKS 29 X PERFORMANCE AND SYSTEM AUDITS 31 XI PREVENTATIVE MAINTENANCE 32 XII ASSESSMENT OF DATA VARIABILITY BIAS ACCURACY REPRESENTATIVE NESS AND COMPLETENESS 33 XIII CORRECTIVE ACTION FOR OUT OF CONTROL SITUATIONS 34 XIV QA
95. DO concentrations using regression equations pro vided by CHEMetrics Inc White and others 1990 8 Quality control e Repeat steps 5 through 7 twice to document precision e To document the variability of DO concentrations within the water system repeat steps 3 through 7 on three sequentially collected samples IODOMETRIC WINKLER 6 2 3 METHOD The USGS currently uses the Alsterberg Azide modification to the Win kler titration procedure for iodometric determination of dissolved oxy gen The accuracy of measurements using the iodometric method should be within at least 0 05 mg L The iodometric method currently is not being used as a standard field method in USGS investigations for measurement of dissolved oxygen because 1 the accuracy achievable can be variable and is dependent on the experience and technique of the data collector 2 potential environmental interferences require advanced knowledge of sample chemistry and 3 field conditions can make preventing exposure of the sample to atmospheric oxygen difficult Nevertheless use of the iodometric method can produce accurate results when correctly implemented The iodometric Winkler method is excellent for calibrating DO instrument systems in a laboratory environment When calibrating amperometric instruments in the laboratory using the Winkler procedure deionized water saturated with air is titrated to determine the DO the DO instrument is then adjus
96. E VISIT 3045 US DH 81 With Teflon Cap And Nozzle Seepage Study 1001 Fixed frequency surface water 3046 Sampler D 77 WiReynolds Oven Collapsible Bag Cross Section Variation 1002 Storm hydrograph surface water 3047 Sampler Frame Type Plastic Bottle W Reynolds Oven Bag 1003 Extreme high flow surface water 3048 Sampler Frame Type Teflon Bottle 3049 Sampler Frame Type Plastic Bottle ALKALINITY ANC PARAMETER e ER dd 3050 Sampler Frame Type Plastic Bottle W Teflon Collapsible Bag CODES 1006 Synoptic surface water 3051 US DH 95 Teflon Bottle 39086 Alkalinity water filtered 1098 NAWQA surface water quality control 3052 US DH 95 Plastic Bottle incremental titration mg L 1099 Other surface water 3053 US 0 95 Teflon Bottle 00410 ANC water unfiltered 3054 150 95 Plastic Bottle incremental titration mg L 3001 NAWQA Occurrence Survey 3055 US D 96 Bag Sampler 29802 Alkalinity water filtered 3002 NAWQA Spatial Distribution Survey 3060 Weighted Bottle Sampler Gran titration mg L 3003 NAWQA Synoptic Study 3061 US WBH 96 Weighted Bottle Sampler 29813 ANC water unfiltered 3098 NAWQA bed sediment or tissue quality control 3070 Grab Sample itrati 3099 Other bed sediment and tissue 3080 VOC Hand Sampler 4010 Thief Sampler 4115 Sampler point automatic A COMPLETE SET OF FIXED VALUE CODES CAN BE FOUND ON LINE AT RUM http wwwnwis er usgs gov nwisdocs4_3 qw QW user book html er SAFETY FIRST EVERY JOB
97. EASUREMENT Air temperature in addition to water temperature should be measured and recorded whenever water quality samples are collected Water tem perature must always be measured in situ and in a manner that ensures that the measurement accurately represents the intended sample condi tions Before measuring air or water temperature gt Inspect the liquid in glass thermometer to be certain that the liquid column has not separated Inspect the glass bulb to be sure it is clean Inspect the protective case to be sure it is free of sand and debris gt Check that batteries are fully charged for thermister thermometers or temperature sensors incorporated into other field meters 6 1 3 AIR Measure air temperature using a dry calibrated thermometer gt Place or hang the thermometer about 5 feet above the ground in a shaded area that is protected from strong winds but open to air circulation Avoid areas of possible radiant heat effects such as metal walls rock exposures or sides of vehicles gt Allow 3 to 5 minutes for the thermometer to equilibrate then record the temperature and time of day gt Measure the air temperature as close as possible to the time when the temperature of the water sample is measured Report routine air temperature measurements to the nearest 0 59 If greater accuracy is required use a thermistor thermometer that has been calibrated to the accuracy needed Temperatu
98. ERATURE Meter MAKE MODEL SIN Thermister S N Thermometer ID Lab Tested against NIST Thermometer Thermister N Y Date C Measurement Location SPLITTER CHURN SPLITTER SINGLE POINT AT ft DEEP VERTICAL AVG OF POINTS FIELD READING 1 2 3 4 5 MEDIAN QUALIFIER pH Meter MAKE MODEL SIN Electrode No Type GEL LIQUID OTHER Sample FILTERED UNFILTERED CONE SPLITTER CHURN SPLITTER SINGLE POINTAT VERTICAL AVG OF POINTS pH BUFFER THEO pH SLOPE MILLI BUFFER BUFFER COMMENTS TEMPERATURE CORRECTION BUFFER TEMP RETICAL BEFORE AFTER VOLTS LOT NO EXPIRA FACTORS FOR BUFFERS APPLIED pHFROM ADJ ADJ TION DATE TABLE CALIBRATION COMMENTS FIELD READING 1 UNITS REMARK __ QUALIFIER SPECIFIC CONDUCTANCE Meter MAKE MODEL S N Sensor Type DIP CUP FLOW THRU OTHER Sample CONE SPLITTER CHURN SPLITTER SINGLE POINT AT ft DEEP AVG OF POINTS Temperature compensation STD STD EXPIRATION AUTO RIEN LOT NO ADJ MANUAL CORR FACTOR _ 0 FIELD READING 1 MEDIAN __ __ QUALIFIER_ 0 DISSOLVED OXYGEN Meter MAKE MODEL SIN Probe No Sample SINGLE POINT AT ft DEEP VERTICAL AVG OF POINTS BOD BOTTLE OTHER Stirrer Used Air Calibration Chamber in Water Air Saturated Water Air Calibration Chamber Air Winkler Titration Other Battery Chec
99. ES 6 3 1 The instrument system used to measure conductivity must be tested before each field trip and cleaned soon after use Many conductivity instruments are available including multiparameter instruments that include conductivity sensors This section provides detailed informa tion on the use of conductivity specific instruments only although instructions regarding conductivity standards and measurement meth ods are applicable in general Users must be familiar with the instruc tions provided by the manufacturer Every conductivity or multiparameter instrument must have a log book in which repairs and calibrations are recorded along with manufacturer make and model description and serial or property number Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 Table 6 3 1 Fquipment and supplies used for measuring conductivity C degrees Celsius less than or equal to gt greater than uS cm microsie mens per centimeter at 25 degrees Celsius L liter Conductivity instrument and conductivity sensor Battery powered Wheatstone bridge Direct readout Temperature range at least 5 to 45 C Temperature compensating 25 C Accuracy Conductivity lt 100 uS cm within 5 percent of full scale Conductivity 2100 uS cm within 3 percent of full scale Thermistor thermometer sensor for automatic temperature compensating models Thermometer liquid in glass or thermistor
100. Extra sensors Gf possible and batteries or backup instrument Conductivity standards at conductivities that approximate and bracket field values Y Compositing and splitting device for surface water samples Flowthrough chamber or downhole instrument for ground water mea surements Y Plastic beakers assorted sizes Soap solution nonphosphate 1 L Hydrochloric acid solution 5 percent volume to volume 1 L Deionized water 1 L maximum conductivity of 1 uS cm Paper tissues disposable soft and lint free Brush small soft Waste disposal container Y Minnow bucket with tether or equivalent for equilibrating buffer solutions to sample temperature Y Instrument log book for recording calibrations maintenance and repairs Modify this list to meet the specific needs of the field effort As soon as possible after delivers the office label conductivity stan dards with the date of expiration aa standards that have expired been frozen have begun to evaporate or that were decanted from the storage container Quality controlled conductivity standards ranging from 50 to 50 000 uS cm at 25 can be obtained by USGS personnel through One Stop Shopping Order standards outside this range from suppliers of chemical reagents Conductivity standards usually consist of potassium chloride dissolved in reagent grade water Specific Electrical Conductance Version 1 2 8 2005 U S Geologi
101. GS Hydrologist Project Manager 804 261 2636 Data Analysis kenhyer usgs gov Sample collection Brian Hasty USGS Hydrologic Monitor Contact Technician Maintenance Project Managers Amy Jensen USGS Hydrologic Discrete Water Contact Technician Quality Sampling Project Managers Study Design Continuously monitoring turbidity probes will be installed at 3 of the River Input Monitoring RIM or Non tidal Network Monitoring stations these established stations are currently monitored by the USGS for the Chesapeake Bay Program and comprise the 9 major non tidal rivers that drain into the Chesapeake Bay The most likely stations to be instrumented with continuous turbidity probes include the Potomac River the Rappahannock River USGS Station Number 01668000 and the James River 02035000 the specific site for continuous monitoring in the Potomac River Basin has yet to be identified These three basins have been selected for this study because they are all major sediment contributors to the Bay Intensive manual sediment monitoring also will be performed during a broad range of flow conditions including low flow intermediate flow and storm flow conditions to provide up to 45 paired measurements of suspended sediment concentrations and associated turbidity values The intensive sediment sampling must be performed over the entire range of hydrologic conditions including extremely high flows because it is during storm flow periods that the maj
102. I 6920 monitors are depolyed in situ and collect values every 15 minutes for pH specific conductance turbidity and water temperature These water quality data are stored in the USGS NWIS database and also are available at http nwis waterdata usgs gov va nwis rt An USEPA Chesapeake Bay program approved Quality Assurance Project Plan is already in place for continuous water quality monitoring Enhanced sediment collection for improving continuous sediment simulations Quality Assurance Quality Control Project Plan December 2005 A copy of the quality assurance quality control plan is provided in Appendix 5 14 Table 2 Virginia River Input Monitoring Program Detection Limits NWIS Code VDCLS Detection VDCLS Analyte storet code Analytical Limit Parameter Container CEDS Code Method Group Dissolved Ammo 00608 EPA 350 1 006 ppm CNTF2 250 mL plastic nia Nitrogen 006085 bottle HDPE Filter Immedi Dissolved 353 2 004 ppm atley and Pre Nitrate Nitrate 631 serve at 4 C Dissolved 00613 EPA 353 2 002 ppm Nitrite 00613 Dissolved 00671 EPA 365 1 002 ppm Orthophosphorus 00671 Dissolved 00955 Standard Methods l ppm Silica 00955 4500 Si F 17th Ed Particulate 00601 EPA 440 0 0 03 ppm BAYR2 1 gallon Cubi Nitrogen PNWLF tainer Preserve at Total Dissolved 00602 Colorimetric Chesa 011 ppm 49C Nitrogen TDNLF peake Bay D Elia
103. L O 411270 ISL O 48 70 88470 5256170 46 70 66470 860870 90870 017870 8 0 71870 72870 2870 07 489 70 89 70 9 70 6470 8 70 48470 06 70 6 70 86 70 70870 40870 60870 21870 9 870 020870 c8 0 9L 0 L9L O ILL O 81470 8270 68 70 68 70 lt 6 70 96 70 00870 v08 0 0870 870 lt 870 81870 22870 0720 2970 99170 69 70 ELL O 14470 08470 v8L O 88 70 6 70 46 70 66 70 20870 90870 OTETO 870 21870 72870 oTe 09 70 v9L O 89 70 ILL O SLL O 6470 84 0 98 70 06 70 v6L O L6L O 1 08 0 40870 60870 FT80 91870 02870 0702 6470 69 70 99 70 04 70 14470 ISL O 48 70 68 70 26470 96 70 00870 0870 70870 870 lt 870 61870 0 6T 484470 I9L O 49 70 69 70 244170 9LL O OSL O v8L O L8L O I6L 0 46 70 66L 0 c08 0 90870 0 870 FTIS8 O 71870 0 8T 9S8L 0 09L O 94 0 L9L O ILL O SLL O 81470 8 70 98 70 06 70 v6L O L6L O 70870 SO8 O 60870 21870 9 8 0 Q ET vSL O 8SL O 29 70 994 0 69L O ELL O LLL O ISL O S8L 0 88L 0 c6L 0 96L 0 00870 08 0 70870 870 SIS8 O 079 EGLO 9470 09 70 vV9L O 89 70 5251270 91470 64170 8 70 18470 I6L O 46 70 86170 250870 90870 01870 870 0 ST 4470 SSL O 66 70 E 9L O 99L O OLL O VLL O 84 70 8 70 98 70 68 70 t 6L O0 26270 710870 40870 60870 21870 077 04 70 4 70 44 70 79270 49 70 69270 ELL O 14170 08470 v8L O 88 70 26 70 96170 00870 0870 20870 870 8vL O 294 0 94 70 094 0 9L O L9L O SLL O 6LL O 8470 48 70 T6L O0 v6L O 864 0 0870 90870 OIS8 O 9 70 OSL O vVSL O 8SL O 29 70
104. Liquid in glass and thermistor thermometers can become damaged or out of calibration especially as a consequence of thermal shock or extended exposure to direct sunlight It is important to be familiar with and to follow the manufacturer s instructions for use and care gt Keep a log book for each thermometer in which the date time and location of every calibration are recorded Avoid direct exposure of the thermometer to sunlight Avoid submerging the thermometer sensor in corrosive solu tions Follow the calibration guidelines and protocols described in section 6 1 2 Chapter A6 Field Measurements Temperature Version 2 3 2006 Digital thermometer casings should not be submerged in water unless the manufacturer affirms that they are water proof Do not allow any liquid to enter open jacks that are part of some digital thermometers gt Keep thermometers clean Clean thermometer sensors with a soft cloth dipped in a mild solution of lukewarm water and nonphosphate detergent If the digital thermometer case needs to be disinfected use a weak 0 005 percent bleach solution Do not autoclave the thermometer unless autoclaving is sanctioned by the manufacturer If your digital thermometer has a detachable sensor with a plug termination periodically wipe off or clean the sensor contacts Dirty contacts can affect temperature readings Blot the thermometer sensor dry after
105. Parkway was added to the storm monitoring network Also in 2005 the USGS began monthly monitoring of water quality conditions at the North and South Fork Shenandoah and Rapidan Rivers In 2007 the USGS began monthly monitoring at the North Anna Chickahominy and James at Richmond Rivers as well as storm monitoring at the North Anna and Chickahominy Rivers In April 2010 the USGS began monthly and storm monitoring at Smith Creek In January 2011 the Rivanna River was added to the storm monitoring network Monthly and annual loads based on a water year October September of selected constituents are estimated using a seven parameter log linear regression model Cohn 1989 C Data Usage The data collected for the Virginia River Input Monitoring Program are used to help define the magnitude timing and sources of nutrient inputs to the Chesapeake Bay from the non tidal areas of the major tributaries in Virginia Additionally this information can help gauge the success of management practices aimed at reducing these inputs These data provide a data base of selected nutrients and suspended solids collected during periods of varying flow and season which are being used to estimate loads to the Chesapeake Bay of the selected constituents Concentration data and statistics from the concentration data will be used to describe the water quality characteristics of each river including concentration ranges and medians the relations between conce
106. Particulate 00667 Colorimetric Chesa 0013 ppm Phosphorus PPWLF peake Bay Aspila Particulate Inor Colorimetric Chesa 0008 ppm ganic Phosphorus PIPLF peake Bay Aspila Total Dissolved 00666 Colorimetric Chesa 003 ppm Phosphorus TDPLF peake Bay Valderrma Particulate Carbon 00694 EPA 440 0 0 05 ppm PCWLF Particulate Inor 00688 EPA 440 0 0 02 ganic Carbon 00688 Total Suspended 00530 Standard Methods 3 mg L Solids 00530 2540 D 17th Ed Volatile Sus 00535 Standard Methods 3 mg L pended Solids 00535 2540 D 17th Ed Fixed Suspended 00540 Standard Methods 3 mg L Solids 00540 2540 D 17th Ed Turbidity 00076 EPA 180 1 0 01 NTU 82079 15 NWIS Code VDCLS Dechen VDCLS Analyte storet code Analytical Lone Parameter Container CEDS Code Method Group Dissolved Organic 40573 Standard Methods 36 ppm DOCFF 4 oz amber Carbon 00681 5310 B 18th Ed glass bottle baked Acid preserva tion Chlorophyll A 70957 EPA 1002 G 4 ppm FCHLR 1 30 7um 32211 GF F glass fiber filter total vloume filtered 300 mL Total Nitrogen 000600 EPA Standard BAYR2 See Above 000600 Method 4500 N Part C 20th ed Total Phosphorus 00665 EPA 365 4 0 01 ppm TPLL 125 mL plastic 00665 bottle HDPE Preserve with H SO and store at 4 C Suspended 80154 ASTM 3977 97 SSC 1 pint wide Sediment SSC Total Method B mouth glass bottle USGS or 500 mL clear plastic bottle DCLS Suspen
107. REPORTING PROCEDURES 34 I PROJECT DESCRIPTION A Background Quantification of the loads of nutrient and suspended solids into the Chesapeake Bay and evaluation of the trends in constituent concentration are necessary in order to determine the effects that these constituents have on the ecosystems of the Chesapeake Bay The Virginia River Input Monitoring Program formerly known as the Virginia Fall Line Nutrient Input Program was developed to quantify and assess the effectiveness of programs aimed at reducing the impact of nutrient and suspended solid inputs Load estimates can further be used to calibrate and validate the computer modeling efforts of the Chesapeake Bay Program The U S Geological Survey USGS began monitoring nutrients and suspended solids in Virginia in 1984 in cooperation with the Virginia Department of Environmental Quality Chesapeake Bay Office VDEQ at that time the Virginia Water Control Board to quantify loads entering Chesapeake Bay from its major tributaries in Virginia The initial monitoring program consisted of collecting water quality data on a twice per month scheduled basis at sites near the Fall Line on four tributaries to the Bay the James Rappahannock Pamunkey and Mattaponi Rivers The Fall Line is geographically defined as the point where the Piedmont Physiographic Province meets the Coastal Plain and in most instances this corresponds to the point farthest downstream that is unaffected by tides Load
108. Record data Clean the cuvette or submersible sensor and repeat measurements of source water and calibrants Record data Calculate bias as the percent difference between the calibrant reading of the uncleaned sensor and the cleaned sensor gt Operator Bias Similar to Operator Variability above bias can result from inconsistencies in methods among different operators Split one water sample into two or more subsamples using a churn splitter Have different operators prepare cuvettes and measure turbidity on the subsamples Consider submitting samples to a laboratory for analysis Calculate bias as the percent difference between the turbidity readings obtained by the different operators Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 50 TBY 6 75 DATA REPORTING AND INTERPRETATION To minimize comparison of data derived from substantially different instrument designs USGS turbidity data are stored according to the instrument designs and reporting units indicated in table 6 7 4 with the method codes describing the specific instrument used Parameter codes associated with instrument design and reporting units and method codes associated with individual instruments are detailed in the Excel spreadsheet at http water usgs gov owq turbidity codes xls accessed 9 30 2005 Method codes are used with these data to provide information that can be used to understand potential differences in turbidity data In some cas
109. TE 6 When using low level reporting scales you may need to subtract a correction factor from the reading to correct for stray light For example the Hach Company reports the correction for the 0 2 NTU scale to be on the order of 0 04 NTU for the Hach 2100P The stray light correction is determined by reading turbidity from an empty instrument without cuvette 5 Record the data in reporting units described in table 6 7 4 using the method code that describes the specific instrument in use Consult table 6 7 3 and the turbidity parameter and methods codes spreadsheet http water usgs gov owq turbidity_codes xls accessed 9 30 2005 If particle settling or instability in initial readings was a problem the results must be qualified as an estimate by using an E remark code for data entered into NWIS QWDATA Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 38 TBY For samples including drinking water with turbidity greater than 40 turbidity units 1 Select an appropriate instrument See table 6 7 4 to select the appropriate USGS parameter code e For drinking water use EPA Method 180 1 a compliant instrument and NTU or NTRU reporting units alternatively select the GLI Method 2 a compliant instrument and FNMU reporting units Reporting units for these methods must be remarked with an E code in NWIS for turbidities greater than 40 e For study objectives other than drinking water choose instr
110. Table 1 presents the basin size the percent land use in the Chesapeake Bay watershed the percent land use in Virginia and the percent land use within each of the basins monitored for this report The locations of the river basins and the River Input monitoring stations are shown in Figure 1 A description of each river basin and each sampling station follows Table 1 Land use for the Chesapeake Bay the Chesapeake Bay watershed in Virginia and selected major river basins in Virginia mi square miles less than Neumiller and others 1995 Chesapeake Bay Program written commun 1994 ay b Total Urban Forested Water percent Geographic area 2 Herbaceous mi percent Woody percent percent percent Chesapeake Bay 64 000 8 33 58 1 100 Virginia 40 815 10 31 58 1 100 James River Basin 10 206 8 25 65 1 99 Rappahannock River Basin 2 848 6 40 54 1 100 Appomattox River Basin 1 600 3 33 61 lt 1 98 Pamunkey River Basin 1 474 3 35 59 2 99 Mattaponi River Basin 911 2 27 69 lt 1 99 3 Includes wetlands V Total percentage below 100 percent is possibly due to rounding and inaccuracies in area estimates Figure 1 Location of major river basins and the River Input Monitoring Stations EXPLANATION James River Basin Rappahannock River Basin Appomattox River Basin York River Basin Potomac River Basin RIM Station NTN Station
111. VOLUME COUNT USED IN REMARKS VOLUME COUNT USED IN REMARKS ML CoL 100ML ML CoL 100ML ML CoL 100ML CALC time in date time in date INCUBATE 24 hrs 44 5 C FILTER SIZE 0 7 uM INCUBATE 24 hrs 35 FILTER SIZE 0 45 OR 0 7 INCUBATE SEE FILTER SIZE 0 45 uM IDEAL COUNT 20 60 COL 100mL IDEAL COUNT 20 80 COL 100mL IDEAL COUNT SEE NFM RESULT 31625 cou100 mL RESULT 31501 COL 100 mL RESULT __ __ QUALIFIER __ __ __ __ QUALIFIER REMARKS E ESTIMATED REMARKS E ESTIMATED REMARKS E ESTIMATED lt LESS THAN gt GREATER THAN lt LESS THAN gt GREATER THAN lt LESS THAN gt GREATER THAN QUALIFIER K NON IDEAL COUNT QUALIFIER K NON IDEAL COUNT QUALIFIER K NON IDEAL COUNT QUALITY CONTROL INFORMATION LOT NUMBERS PRESERVATIVES 7 5N FOR METALS amp CATIONS 6N HCI FoR Hg 4 5N gt 504 FOR NUTRIENTS amp DOC 1 1 HCL FOR voc CONC H2S0 4 FOR COD PHENOL O amp G NaOH FOR CYANIDE OTHER COMMENTS SPIKE VIALS 99104 SURROGATE VIALS BLANK WATER INORGANIC 99200 992021 PESTICIDE 99202 99203 voc 99204 FILTERS CAPSULE ORGANIC CARBON OTHER CROSS SECTION NOTES STATION ft FROM LEFT DO SAT GAGE HT BANK 00009 oR units ft ft FROM RIGHT 00300 00301 00400 00065 BANK 72103 STN NO OX
112. YGEN DEMAND BOD CBOD BOTTLE INITIAL DO 5 DAY CBOD AVERAGE RESIDUAL CHLORINE NO BOD OR BOD positive sodium sulfite sodium sulfite CBOD CBOD negative added normality cope After 5 day l bod cbod CALCULATIONS SAMPLE INITIAL 5 DAY BODs mg L D1 D Size BOD p BOD P DILUTIION CBOD where D initial DO of sample D final DO of sample after 5 days and P decimal volumetric fraction of sample used DISSOLVED OXYGEN USING WINKLER METHOD SODIUM THIOSULFATE OTHER TITRANTNORMALITY mg IL FINAL BURETTE READING COMMENTS INITIAL BURETTE READING DISSOLVED OXYGEN mg L mL water titrated mL TITRANT x CF CORRECTION FACTOR CF IF TITRANT HAS A NON STANDARD NORMALITY STANDARD NORMALITY 0 025N CF NORMALITY OF TITRANT 0 025 TURBIDITY CALIBRATION Meter MAKE MODEL SIN Type TURBIDIMETER SUBMERSIBLE SPECTROPHOTOMETER Sample SAMPLE STORED Y HOW LONG SAMPLE DILUTED Y X VOL OF DILUTION WATER mL SAMPLE VOLUME mL Date Concentration Temperature Initial instrument Reading after A NTU IN DILUTED SAMPLE Prepared NTU reading adjustment B VOLUME OF DILUTION WATER mL C SAMPLE VOLUME mL Stock Turbidity Standard Zero NTU COMMENTS Standard DIW Standard 1 Standard 2 Standard 3 FIELD READING 1
113. a flowthrough chamber instead of being deployed in situ for monitoring ground water field measurements See the section below on dynamic determination of turbidity 6 7 3 8 DYNAMIC SUBMERSIBLE SENSOR DETERMINATION Determination of turbidity using a submersible sensor or sensor in a multiparameter sonde is useful for site specific water quality studies Such turbidity data can be used for watershed investigations for example for determination of visual impairment Davies Colley and Smith 2001 for correlation with concentrations of suspended sediment total phosphorus or other chemical constituents and indicator bacteria Christensen and others 2000 Uhrich and Bragg 2003 and for long term monitoring Turbidity sensors for these applications utilize a variety of different light sources and other options to compensate for interferences fig 6 7 2 table 6 7 3 Multiparameter instruments with internal batteries and memory can be used in surface water studies that require long term deployment Guidelines for long term instrument deployment fall under the topic of continuous monitors and are beyond the scope of this section refer to the manufacturer s instructions and recommendations and to guidance documents such as Wagner and others 2000 Some submersible turbidity sensors can be adjusted to operate within differing turbidity ranges For example although the maximum turbidity based on factory settings is just over 1 000
114. agner R J Boulger Jr R W Oblinger C J and Smith B A 2006 Guidelines and standard procedures for continuous water quality monitors station operation record computation and data reporting U S Geological Survey Techniques and Methods 1 D3 available online only at http pubs water usgs gov tm1D3 Weiss R F 1970 The solubility of nitrogen oxygen and argon in water and seawater Deep Sea Research v 17 p 721 735 White A F Peterson M L and Solbau R D 1990 Measurement and interpretation of low levels of dissolved oxygen in ground water Ground Water v 28 no 4 p 584 590 Wood W W 1981 Guidelines for collection and field analysis of ground water samples for selected unstable constituents U S Geological Survey Techniques of Water Resources Investigations book 1 chap D2 p 22 24 Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 48 DO ACKNOWLEDGMENTS This National Field Manual responds to advances in technology and science and to the developing needs for water quality monitoring Its aim is to provide scientifically sound guidance to USGS personnel and to document USGS requirements for collecting water quality data As a result the expertise of numerous scientists has been tapped in devel oping this manual and keeping it current A great debt of gratitude is owed to the following original authors editors and reviewers of Chap ter A6 Section 6 2 of this field
115. al Survey WRD 804 261 2636 or 804 261 2634 Fax 804 261 2657 Field Sampling Laboratory Data Management Analysis USGS VDCLS USGS Hydrologic Jay Armstrong Hydrologist 2 804 648 4480 Nutrients Chris Morton 804 648 4480 Solids Bailey Davis Carbon and Chlorophyll A 804 648 4480 USGS KY Sediment Lab 502 493 1944 Technicians and Hydrologic Technician Hydrologists as needed VDEQ Cindy Johnson 804 698 4385 same phone and fax numbers as above Data Analysis USGS Hydrologist 3 0565 Baltimore MD Hydrologist 443 498 5560 VDEQ Virginia Department of Environmental Quality Richmond USGS U S Geological Survey VDCLS Virginia Division of Consolidated Laboratory Services Richmond VA 17 PROJECT OFFICER Frederick Hoffman Virginia Department of Environmental Quality Box 1105 Richmond VA 23218 804 698 4334 Fax 804 698 4032 Responsible for overseeing the administrative aspects of the program including fiscal management coordination among other administrators and coordination with cooperating agencies and institutions Approves technical design conduct and data analysis of the program PRINCIPAL INVESTIGATORS Kenneth E Hyer 804 261 2636 Douglas L Moyer 804 261 2634 U S Geological Survey WRD 1730 East Parham Road Richmond VA 23228 Fax 804 261 2657 Responsible for the technical design conduct and data analysis of the program Provides guidance to other
116. al Survey Water Supply Paper 2254 p 155 156 In Situ Inc Multi parameter water quality Troll 9500 accessed April 29 2006 at http www in situ com In Situ Products TROLL9500 TROLL9500 html Kane J A Improved optical sensor for monitoring dissolved oxygen in NASA Tech Briefs KSC 11998 accessed September 27 2005 at http www nasatech com Briefs Nov99 KSC11998 html Skougstad M W Fishman M J Friedman L C Erdmann D E and Duncan S S eds 1979 Methods for determination of inorganic substances in water and fluvial sediments U S Geological Survey Techniques of Water Resources Investigations book 5 chap Al 626 p Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 47 U S Geological Survey 1979 Analytical methods recommended procedures for calibrating dissolved oxygen meters Quality of Water Branch Technical Memorandum 79 10 accessed March 17 2006 at http water usgs gov admin memo QW qw79 10 html U S Geological Survey 1981 Water quality new tables of dissolved oxygen saturation values Quality of Water Branch Technical Memorandum 81 11 accessed March 17 2006 at http water usgs gov admin memo QW qw81 11 html U S Geological Survey variously dated National field manual for the collection of water quality data U S Geological Survey Techniques of Water Resources Investigations book 9 chaps A1 A9 available online at http pubs water usgs gov twri9A W
117. an Teflon stirring bar and stir the sample at a moderate rate without aerating the sample i Add increments of sodium thiosulfate titrant until the color turns pale straw yellow j Add 1 to 2 mL of starch indicator solution This causes the sample to turn dark blue k Very slowly add more sodium thiosulfate titrant until the sample just turns clear A white background behind the bottle will help you see the color change 1 Record the volume of sodium thiosulfate titrant used in milliliters e Fora 200 mL sample the volume of titrant added is directly proportional to the amount of DO in milligrams per liter e To calculate DO for a sample volume greater or less than 200 mL 200 X titrant added in mL sample volume DO mg L m Record the DO value Rinse the equipment with deionized water n Quality control The titration values for the duplicate samples should agree within 0 1 mg L If they do not repeat the titration on a third sample 7 Recheck the field instrument for proper functioning following the manufacturer s instructions Adjust the calibration control until the DO instrument system reads the DO concentration determined from the iodometric measurement Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 33 REPORTING 6 2 4 USGS personnel are instructed to enter the DO value on the National Water Quality Laboratory Analytical Services Request form and
118. andard to be used 8 Put the sensor and the thermometer into the rinsed container and pour in fresh calibration standard 9 Measure water temperature Accurate conductivity measure ments depend on accurate temperature measurements or accurate temperature compensation e Ifthe sensor contains a calibrated thermistor use this ther mistor to measure water temperature e a manual instrument without a temperature display or temperature compensation adjust the instrument to the temper ature of the standard using a calibrated liquid in glass or a ther mistor thermometer 10 Agitate a submersible type conductivity sensor up and down under the solution surface to expel air trapped in the sensor Read the instrument display Agitate the sensor up and down under the solu tion surface again and read the display Repeat the procedure until consecutive readings are the same Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 9 11 Record the instrument reading and adjust the instrument to the known standard value e For nontemperature compensating conductivity instruments apply a temperature correction factor to convert the instrument reading to conductivity at 25 C e Thecorrection factor depends to some degree on the specific instrument used use the temperature correction factor recom mended by the manufacturer If this is not available use correc tion factors from tabl
119. ankow J F 1991 Aquatic chemistry concepts Chelsea Mich Lewis Publishers p 109 127 pH meter info 2005 pH electrode pH meter info Web page at http www ph meter info pH electrode construction Accessed July 14 2008 Roberson C E Feth J H Seaber P R and Anderson Peter 1963 Differences between field and laboratory determinations of pH alkalinity and specific conductance of natural water U S Geological Survey Professional Paper 475 C p C212 C215 Raghuraman B Gustavson G Van Hal R E G Dressaire E and Zhdaneev O 2006 Extended range spectroscopic pH measurement using optimized mixtures of dyes Applied Spectroscopy 60 no 12 p 1461 1468 available online at http as osa org abstract cfm id 121890 Accessed August 12 2008 Sedjil M and Lu G N 1998 A seawater pH determination method using a detector Measurement Science and Technology v 9 p 1587 1592 available online at http www iop org EJ abstract 0957 0233 9 9 03 1 Accessed August 12 2008 Stumm Werner and Morgan J J 1981 Aquatic chemistry An introduction emphasizing chemical equilibria in natural waters 2d ed New York John Wiley p 131 134 and 483 487 U S Geological Survey variously dated National field manual for the collection of water quality data U S Geological Survey Techniques of Water Resources Investigations book 9 chaps 1 9 available online at http pubs water usgs gov twri9A
120. ant 25 times 1 second inversion cycle followed by a 2 to 10 minute wait to allow for bubble removal Calibrants of 40 turbidity units or less will remain suspended for up to 30 minutes calibrants greater than 40 turbidity units may require more frequent resuspension Do not use calibrants with flocculated suspensions 2 on the turbidimeter and allow it to warm up Check manufacturer s instructions for equipment startup Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 Select the desired turbidity range Use a calibration range to equal the high value of calibrant for the range of interest Rinse a clean dry scratch free cell with the highest concentration of the calibrant for the instrument range setting or range of interest Index mark the cell to ensure consistent orientation within the instrument See manufacturer s instructions for index marking the cell a Hold the sample cell by the rim top lip not beneath the lip b Pourcalibrant into the sample cell to the fill mark c Wipe the exterior of the cell using a soft lint free cloth or tissue to remove moisture condensation from cell walls d Apply a layer of silicon oil onto the exterior of the cell to reduce condensation on the cell and to mask slight scratches and nicks Apply silicon oil uniformly onto the blank cell if it will be used on the cell filled with calibrant follow manufacturer s recommendations e Before in
121. ar b Allow the sensors to equilibrate with the ground water for 5 minutes or more at the flow rate to be used for collecting all of the other samples c Record pH values at regularly spaced time intervals throughout purging consult 6 0 for detailed guidance Compare the variability of pH values toward the end of purging The stability of pH values is assumed when three to five readings made at regularly spaced intervals are constant If readings continue to fluctuate continue to monitor or if site conditions are demonstrably variable degassing in gassing rapid thermal changes from water at depth select the median of three or more readings within about 60 seconds as the value recorded for the specific time interval 5 Determine sample pH toward the end of purging for example during removal of the final purge volume as follows a Divert flow from the chamber to allow the sample contained within the chamber to become quiescent after recording the other field measurements Record the pH value under quiescent conditions to the nearest 0 01 pH unit b Determine the median of the pH values recorded under quiescent conditions and report this value as sample pH c If field personnel have reason to suspect an electrode malfunction a calibration check at the end of sampling is recommended To make a pH measurement on a bailed sample fig 6 4 3 1 Withdraw subsamples from the well and transfer each bailed sample to
122. are used routinely to determine the concentration of dissolved oxygen in fresh to saline unfiltered surface and ground waters Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 4 DO gt The amperometric method section 6 2 1 has been the standard USGS procedure for the past 10 to 15 years for determining aquatic DO concentrations that exceed 1 milligram per liter mg L Theluminescent based sensor method section 6 2 1 uses relatively new technology and applies to the same environmental conditions as the amperometric method gt Thespectrophotometric method section 6 2 2 for example the Rhodazine D technique is recommended for determining concentrations of DO less than 2 0 mg L gt The iodometric Winkler method section 6 2 3 is regarded as an accurate and precise method for the determination of dissolved oxygen in water however it is not a standard USGS method for field determinations of DO because the accuracy and reproducibility achieved depend largely on knowledge of the presence of possible sources of interference nitrite ferrous or ferric iron and organic matter for example and on the experience and technique of the data collector In a laboratory environment the method is excellent for calibrating DO instrument systems Some procedures for equipment operation recommended in this guidance document may not apply to your equipment as a result of recent technological advanc
123. arkway 10 the James River near Richmond 11 the North Anna River at Hart Corner near Doswell 12 the Chickahominy River near Providence Forge 13 Smith Creek near New Market 14 the Rivanna River at Palmyra USGS 02035000 VDEQ 2 JMS157 28 Discontinued sampling by DEQ 3 2001 USGS 01668000 VDEQ 3 RPP113 37 Discontinued sampling by DEQ 3 2001 USGS 02041650 VDEQ 2 APP016 38 Discontinued sampling by DEQ 6 1999 USGS 01673000 VDEQ 8 082 34 Discontinued sampling by DEQ 4 2003 USGS 01674500 VDEQ 8 054 17 Discontinued sampling by DEQ 4 2003 USGS 01634000 VDEQ 1BNFS010 34 USGS 01631000 VDEQ 1 55 003 56 USGS 01667500 VDEQ 3 RAPO030 21 USGS 02024752 VDEQ 2 JMS279 41 USGS 02037618 VDEQ 2 JMS113 20 USGS 01671020 VDEQ 8 005 42 USGS 02042500 VDEQ 2 CHK035 26 USGS 01632900 VADEQ 1BSMT004 60 USGS 02034000 VADEQ 2 RVNO015 97 Water quality sample collection began July 1 1988 for the James Cartersville and the Rappahannock Rivers and July 1 1989 for the Appomattox Pamunkey and Mattaponi Rivers Samples are collected once per month on a scheduled basis which most often occurs during baseflow conditions Samples also are collected during stormflow conditions in order to cover a range in flow conditions Stormflow water quality sample collection began July 1 2004 for the North and South Fork Shenanadoah Rapidan and James Richmond Rivers In 2005 the James River at the Blue Ridge
124. ased on the latest calibration of the pH electrode Ionic filling solutions An ionic solution used to fill the space within the pH electrode is the source of mobile chemical ions that serve to complete the electrical circuit between the internal reference and pH measurement electrodes The pH electrode may be filled either with an ionic liquid solution liquid filled pH electrode or an ionic gel solution gel filled pH electrode Typically these ionic solutions contain a chloride salt usually silver or potassium of a known and specific molarity strength For liquid filled electrodes maintaining a sufficient volume and the correct molarity of the filling solution within the electrode is very important to achieving meaningful measurements Most standard pH electrodes are designed to function well when the electrode filling solution strength is similar to the sample ionic strength typically having a relatively high ionic strength of 3 molar M or greater Using low ionic strength or high ionic strength pH electrodes and a filling solution of appropriate composition and molarity as recommended by the electrode manufacturer is recommended when working with environmental samples having conductivities less than 100 uS cm or greater than 20 000 uS cm respectively Reference junction The liquid reference junction sometimes called the salt bridge is an electrically conductive bridge within the pH electrode between the reference ionic solutio
125. asured using a benchtop static method Dynamic measurement is preferred to static measure ment because of problems with representative subsampling settling of solids and temperature changes in static samples and interferences such as condensation or scratches on sample cuvettes Dynamic techniques usually are required for continuous monitoring and the sensors often can be combined with other sensors that measure additional properties such as temperature specific conductance dissolved oxygen and pH In some cases however dynamic readings are not feasible or desired for example if a measurement is needed of a composite sample or in a laboratory setting Most instruments used for static measurements are not capable of being used for dynamic measurements whereas some instruments used for dynamic measure ments can be immersed in a water sample and the measurement taken statically What resolution is required in the resulting data For turbidity data that primarily will be in the low less than 5 turbidity units or ultra low less than 1 unit ranges the necessary resolution may be down to the 100th or 10th decimal place whereas for turbidi ties greater than 40 units resolution to the nearest 5 10 or even 100 reporting units might be adequate After determining the primary instrument design requirements consult literature or online sources of individual instrument manufacturers for information on available resolution Turbidit
126. ata base using the appropriate reporting units parameter codes and method codes according to tables 6 7 3 and the methods and parameter codes spreadsheet http water usgs gov owg turbidity_codes xls Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 46 TBY To make spectrophotometric determinations of turbidity 1 Before starting check operating instructions for the specific instrument in use 2 Enter the stored program number for turbidity if any Record the light wavelength used A wavelength of 860 nm bandwidth 60 nm is specified by ISO 7027 for reporting in FAU Use a set of clean matched 10 mL sample cells 4 Calibrate according to instructions in the instrument s operating manual see section 6 7 2 5 Ifrecently calibrated take check measurements using calibration solutions that bracket the range anticipated in the sample solution Clean the 10 mL cell after using calibrants 6 one cell to the 10 mL mark with turbidity free water and cap with a stopper NOTE If measurement of color derived turbidity is not desired filter using a 0 2 um pore size filter an aliquot of the sample water and use this water in place of turbidity free water 7 Place blank sample into the cell holder close the light shield and verify a zero reading 8 the other cell to the 10 mL mark with sample water and with a stopper Gently invert 25 times to suspend all particulates 9 Carefully
127. ated contaminants such as phosphorus and bacteria Christensen 2001 The Chesapeake Bay the Nation s largest estuary also has been degraded through water quality problems loss of habitat and over harvesting of living resources Excess sediment is having an adverse effect on the living resources and associated habitat of the Chesapeake Bay and its watershed Because of excess nutrient and sediment levels the Chesapeake Bay was listed as an impaired water body in 2000 under the Clean Water Act The Bay must meet regulatory water quality standards by 2010 and the CBP needs information with which to evaluate current conditions and progress towards meeting sediment reduction measures In most streams the majority of suspended sediments are transported during storm flow periods Wolman and Miller 1960 the very time when the fewest data are generally collected Although manual sampling of suspended sediment concentrations will produce an accurate series of point in time measurements robust extrapolation to the many unmeasured periods especially high flow periods has proven difficult because of the inherently complex nature of suspended sediment transport Suspended sediment transport during storm events is extremely variable and it is difficult to relate a unique concentration to a given stream discharge In one study Christensen and others 2002 identified that only 50 of their eight study stations actually had significant correlations betwee
128. ater whether resulting from dissolved compounds or suspended particles can affect a turbidity measurement TURBIDITY an expression of the optical properties of a liquid that causes light rays to be scattered and absorbed rather than transmitted in straight lines through a sample ASTM 2003a Although turbidity is not an inherent property of water as is temperature or pH Davies Colley and Smith 2001 the recognition of turbidity as an indicator of the environmental health of water bodies has increased over the past decade resulting in a growing demand for high quality and objective turbidity measurements To meet this demand relatively inexpensive yet sophisticated instruments have been developed that allow for nearly continuous monitoring and data logging of turbidity in natural waters Gray and Glysson 2003 note the following examples of disparate uses for turbidity data Regulating and maintaining drinking water clarity Determining water clarity for aquatic organisms Indicating visual impairment in water Real time monitoring that indicates watershed conditions v v vV v Vv Developing surrogates for concentration of suspended sediment SSC and other constituents gt Monitoring the effects of land development and related human activities and subsequent management of natural resources gt Determining transport of contaminants associated with suspended materials Chapter A6 Field Measurements Turbidit
129. ater quality monitoring station was added in the Pamunkey River basin This new station is the North Anna River at Hart Corner near Doswell Va USGS station 01671020 and VDEQ station 8 NARO005 42 The drainage area of this watershed is 462 mi The location of this monitoring site is lat 37951700 long 7792541 NAD83 in Hanover County VA The Mattaponi River basin is 911 mi or two percent of the area of Virginia and also is located within both the Piedmont and Coastal Plain physiographic provinces Like the Pamunkey River it tends to have expanses of wetland areas VWCB 1991 The wetland areas tend to slow flow velocities and the hydrographs during storms are slower to peak and recede than at the Pamunkey River The Mattaponi River monitoring station USGS station 01674500 and VDEQ station TF4 3 VDEQ Discontinued 3 2001 is located near Beulahville Va The area of the drainage basin above the sampling station is approximately 601 mi which is about 23 percent of the entire York River basin and two percent of the area of Virginia Like the Pamunkey the Mattaponi River basin has expanses of freshwater wetlands VWCB 1991 The average discharge at this station is 583 ft s computed during a period of 50 years Prugh and others 1994 The location of the site in King and Queen County is lat 37 53 16 long 77 09 47 NAD83 In 2004 two additional water quality monitoring stations were added in the Shenandoah River Basin Th
130. ations entitled Quality Assurance Plan for the Virginia Division of Consolidated Laboratory Services 1982 and Quality Assurance Practices for the Chemical and Biological Analyses of Water and Fluvial Sediments by F C Friedman and D E Erdmann Washington U S Govt Print Off 1982 Calibration of the laboratory equipment at the USGS sediment lab in Louisville KY is documented in the publication entitled Quality Assurance Plan for the Analysis of Fluvial Sediment by the Northeastern Region Kentucky District Sediment Laboratory Sholar and E A Shreve Open file report 98 384 Louisville Kentucky 1998 Calibration of laboratory equipment at NWQL is documented in the publications entitled Quality Assurance Practices for the Chemical and Biological Analyses of Water and Fluvial Sediments by F C Friedman and D E Erdmann Washington U S Govt Print Off 1982 and in Methods for Determination of Inorganic Substances in Water and Fluvial Sediments M J Fishman and L C Friedman Open file report 85 495 Denver 1985 26 VII ANALYTICAL PROCEDURES The majority of samples collected are analyzed by VDCLS Samples collected prior to January 15 1994 were filtered and analyzed by VDCLS under criteria established by Clesceri Greenberg and Trussell 1989 and the USEPA Environmental Monitoring and Support Laboratory 1983 Beginning January 15 1994 samples have been filtered in the field using procedures established by Horowitz and
131. ative or posi tive value measured as described below Thermistor thermometer measurements Store manually recorded temperature measurements in the data base to the user verified precision of the instrument generally 0 1 or 0 2 C provided that the thermometer calibration verifies this accuracy Electronically recorded temperature data may be stored unrounded Unrounded temperature data in the database must be rounded when retrieved for publication Liquid in glass thermometer measurements Record temperature measurements in the data base to the nearest 0 5 C gt Any values less than 0 1 C are highly questionable and should be published only after a complete calibration check of the equipment used gt USGS field measurements of air and water temperature must be entered on the paper or electronic field form and stored in the NWIS data base Be sure to store all data under the correct parameter and method if available codes Store air and water temperature measurement data with rep licate samples only if replicate measurements were made Enter replicate measurements under the correct medium code for quality control QC samples alternatively distin guish the replicate from the regular sample by using the unique time of sampling that was assigned to QC samples for that site and date Do not store the regular sample measurement data with the replicate sample data Enter regular sample data only once in th
132. be temperature compensating the perme ability of the membrane and solubility of oxygen in water change as a function of temperature gt All built in thermistor thermometers must be calibrated and field checked before use as described in NFM 6 1 Temperature gt Some manufacturers provide membranes of different thicknesses the selection of which 1s based on the intended use of the instrument Select the sensor membrane based on manufacturer recommendations Two basic types of membrane design are available a loose membranes and b membrane cap assemblies Loose membranes are considerably less expensive but are more difficult to install Sensor performance can be affected by the manner in which loose membranes are installed and conditioned after installation After membrane replacement allow a minimum of 2 to 6 hours for the new membrane to condition before calibration and use e For greater stability during calibration allow the new mem brane to condition overnight prior to calibration e If conditions necessitate using the sensor and new membrane before the recommended overnight conditioning time more frequent calibration checks and possibly recalibration are necessary for accurate DO measurements Luminescent based sensors Manufacturers of luminescent based DO sensors can provide very different guidance on the care and main tenance of their particular sensor Read and follow the manufacturer s guidance for
133. before making pH measurements as suction pressure may affect the proper movement of ions in the filling solution and the correct operation of the reference junction Re plug the fill hole after use f using an electrode after it has been in a storage solution uncap the fill hole and suspend the electrode in the air for about 15 minutes This will allow the filling solution to flush residual storage solution through the porous reference junction and thoroughly wet the junction After 15 minutes visually inspect the junction for liquid or new salt accumulation Ensure that the filling solution is flowing freely Refer to the manufacturer s instructions 2 Check the filling solution level and replenish it if necessary The solution should reach the bottom of the fill hole Filling solutions differ in molarity and composition always check that the correct filling solution required by the manufacturer for a particular electrode is being used 3 Drain and flush the reference chamber of refillable electrodes and routinely refill them with the correct filling solution check the manufacturer s recommendations 4 Keep a record of the electrode and meter operation and maintenance and repairs in the pH meter electrode logbook Record in the calibration logbook the operational history of each pH electrode Record the Nernst slope reading and the millivolt readings at pH 4 7 10 or other pertinent pH buffer values based on field study
134. boratory and the reference to the method used RIM Samples are analyzed for the following constituents Nitrogen species particulate nitrogen total dissolved nitrogen dissolved ammonia nitrogen dissolved nitrite plus nitrate dissolved nitrate total nitrogen Prior to February 1996 total Kjeldahl nitrogen ammonia plus organic species was also determined The concentration of dissolved nitrite is the difference of dissolved nitrite plus nitrate concentration and dissolved nitrate concentration Phosphorus species particulate phosphorous total dissolved phosphorous dissolved orthophosphorus particulate inorganic phosphorus total phosphorus Other species dissolved silica particulate carbon particulate inorganic carbon dissolved organic carbon chlorophyll a total suspended solids fixed suspended solids suspended sediment and percent fines RIM sites Processed by the USGS sediment lab in Louisville Kentucky Add on sites processed by the Virginia Consolidated Laboratories RIM Add On Samples are analyzed for the following constituents Nitrogen species total nitrogen total ammonia and total nitrate and nitrite Phosphorus species dissolved orthophosphorus and total phosphorus Other species Suspended sediment processed by the Virginia Consolidated Laboratories for total suspended solids fixed suspended solids suspended sediment and percent fines Approximately 40 samples per year were initially n
135. buffer Replace the electrode if after recalibration the slope remains outside the acceptable range of 95 to 102 percent or if the acceptable range of the millivolt response is not met at any of the calibration points pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 19 CALIBRATION FOR LOW IONIC STRENGTH WATER 6 4 3 B Calibration of pH instrument systems with standard buffers does not guarantee accurate and or timely pH measurement in low ionic strength waters conductivity less than 100 uS cm and in very low ionic strength waters conductivity less than 50 uS cm As sample ionic strength decreases the efficiency of the standard pH instrument system also decreases Low or very low ionic strength waters have little buffering capacity and may readily absorb atmospheric CO resulting in the formation of carbonic acid in the sample A continuous change in pH values can occur from the varying reaction rates of the sample water with CO resulting in an unstable measurement Standard pH electrodes do not respond well in waters with low ionic strength gt Standard combination pH electrodes respond more slowly the response is characterized by continual drift and calibration is difficult to maintain Equilibration with the sample water may not be completely achieved or the equilibration time may be on the order of hours gt Standard pH electrodes exhibit a jumpy response and more sensitive to conditions of fl
136. by the U S Environmental Protection Agency USEPA only for water that is intended for use as drinking water In some cases States use turbidity for regulations associated with the Clean Water Act U S Environmental Protection Agency 2002a To date the USEPA has approved the following three methods to measure turbidity in drinking water 1 EPA Method 180 1 U S Environmental Protection Agency 1993 based on white light nephelometric instrument designs 2 GLI Method 2 U S Environmental Protection Agency 1999 Great Lakes Instrument Company undated which uses a dual beam and dual detector technology with an 860 nm light emitting diode LED light source to compensate for color and reduce erratic readings and 3 Hach Method 10133 U S Environmental Protection Agency 2002b an inline process stream method that is unlikely to be used within USGS Owing to a nonlinear response of these technologies at high turbidities their applicable range in drinking water is from 0 to 40 turbidity units Instrument designs that conform to EPA Method 180 1 or GLI Method 2 may perform poorly including nonlinear responses at turbidities that commonly occur in surface water bodies greater than 40 turbidity units Also white light instruments typically consume more power than monochrome instruments so access to the regional power grid is commonly required For these methods waters with turbidities greater than 40 Chapter A6 Field Measurem
137. cal Survey TWRI Book 9 SC 5 CONDUCTIVITY SENSORS 6 3 1 A Conductivity sensors are either contacting type sensors with electrodes or electrodeless type sensors gt Contacting type sensors with electrodes Three types of cells are available 1 a dip cell that can be suspended in the sample 2 a cup cell that contains the sample or 3 a flow cell that is connected to a fluid line Choose a cell constant on the basis of expected conductivity table 6 3 2 The greater the cell constant the greater the conductivity that can be measured The cell constant is the distance between electrodes in centimeters divided by the effective cross sectional area of the conducting path in square centimeters gt Electrodeless type sensors These operate by inducing an alternating current in a closed loop of solution and they measure the magnitude of the current Electrodeless sensors avoid errors caused by electrode polarization or electrode fouling Table 6 3 2 Example of cell constants for contacting type sensors with electrodes and corresponding conductivity ranges Conductivity range in microsie Cell constant mens per centimeter in 1 centimeter 0 005 20 01 200 4 10 2 000 1 0 100 20 000 10 0 1 000 200 000 50 0 CAUTION Before handling conductivity standards or acids refer to Material Safety Data Sheets MSDS for safety precautions Chapter A6 Field Measurements Spec
138. cal surface of sensor tap sample line to flowthrough cell or chamber systems to dislodge bubbles adjust degassing apparatus remove bubbles on sonde sensor system by agitating the unit repeatedly or by activating the wiper mechanism Unusually high or low turbidity Bubbles in sampling system or on optical surface of sensor see Erratic reading symptom Fouling of optical surfaces Clean with lint free cloth or toothbrush Wiper mechanism is parking on optical surfaces Use software to reset wiper or replace wiper mechanism may require factory repair Inappropriate turbidimeter for environmental conditions See tables 6 7 1 6 7 2 and 6 7 3 or figure 6 7 2 to determine most appropriate turbidimeter type Calibration value out of range Contaminated calibrant solution or value entered incorrectly Verify intended calibrant value and start over If problem persists try using a different batch of calibrant solution Readings first appear stable then begin to increase inexplicably Check for moisture on cell wall see Moisture symptom Moisture condensation on cell wall static turbidimeter or spectrophotometer Wipe cell dry with soft lint free cloth Apply a thin veneer of silicon oil first check instrument manufacturer s instructions Add gas sweep to system Blank samples or reference material standards do not read accurately Check that the cells are oriented as in
139. ch use inspect the instrument temperature sensor digital display wires or leads and plugs for signs of wear or damage check that batteries are at full voltage If the thermometer has been improperly stored or used exposed at some length to sunlight or heat or extreme cold or if its accuracy is otherwise in question check its readings at five temperatures within the range of 0 to 40 C against those of another currently certified calibration thermometer If the environmental air or water temperatures to be mea sured fall below or exceed this range add calibration points to bracket the anticipated temperature range gt Once NIST certification has expired exceeded the 2 year USGS limit thermometer either must be replaced with a currently certified thermometer or be recertified through a profes sional calibration service An office laboratory calibration check does not constitute recertification of NIST traceability of a calibration thermometer Itis advisable to replace all mercury thermometers with a spirit or thermistor thermometer in order to avoid potential mercury contamination The mercury thermometer must be disposed of in strict accordance with safety regulations Do not use calibration thermometers as routine field thermometers Reserve their use for calibrating field thermometers FIELD THERMOMETERS 6 1 2 Field thermometers whether of the liquid in glass or thermistor digital ty
140. d sample that is withdrawn from a churn or cone splitter or other approved sample compositing device Although referred to as a single parameter method most modern pH meters are equipped with a thermistor used to determine the temperature of the sample Each pH measurement must be accompanied with a concurrent temperature measurement Itis not advisable to immerse the pH electrode into flowing surface water for the following reasons Placing the pH electrode into moving water risks damage to the delicate glass membrane scratching pitting coating which will inhibit the correct functioning of the electrode In addition proper functioning of the glass membrane is affected when ionic equilibrium is not achieved with the surrounding sample solution Calibration of the electrode was accomplished in a quiescent sample not in flowing or stirred water Adequate calibration of the instrument system cannot be assumed to extend to moving water USGS methodology in surface water measurement usually involves the collection of depth and width integrated samples In situ measurements of pH in a moving water system either at a singular point in the waterway or across a section do not meet these requirements Reference junction equilibrium cannot be achieved in moving water thus correct electrode functioning will again be inhibited Itis difficult to have electrode temperature come to equilibrium with sample temperature in mo
141. daily or weekly and long term 2 to 4 months storage requirements of the electrode General guidelines for short term storage 1 Storage solutions are specific to the type of electrode check the manufacturer s manual for each electrode Do not store glass hydrogen ion electrodes in DIW unless instructed to do so by the manufacturer 2 Storage solutions have a limited shelf life Label storage solution containers with the expiration date and discard expired solutions on that date and in a proper manner 3 Do not place a small piece of cotton or paper towel in the electrode cap to help keep it moist as this can scratch the glass membrane sensor 4 Store liquid filled pH electrodes upright 5 Store liquid filled electrodes wet between uses to maximize their accuracy and response time The glass membrane bulb should be fully immersed in the proper electrode storage solu tion Between field sites replace the plug on the fill hole and cover the electrode bulb with the cap Fill the cap with enough storage solution to keep the bulb wet 6 Gel filled electrodes should be stored according to the manufacturer s instructions General guidelines for long term storage 1 Liquid filled electrodes may need to be drained of filling solution follow the manufacturer s instructions 2 Clean the electrode contacts and connector with alcohol if necessary Allow the contacts to dry and seal and store them in a plastic bag 3
142. dations To account for the effects of properties of water or interferences on turbidity many types of instruments have been designed table 6 7 3 many with multiple light beams or detectors fig 6 7 1 For example although stray light can cause a positive bias in turbidity measurement because of apparent additional reflectance many newer instruments particularly those used for dynamic monitoring are designed to minimize stray light For a valid comparison of turbidity data over time between sites and among projects use instruments with identical optical and data processing configurations Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 6 TBY Table 6 7 1 Properties of water matrices and their expected effect on turbidity measurement Negative a negative effect produces a disproportionately low measurement IR infrared nm nanometers positive a positive effect produces a disproportionately high measurement approximately See table 6 7 3 for descriptions of instrument designs Properties of water matrix Effect on the measurement Direction of effect on the measurement Instrument designs to compensate for effect Colored Absorption of light beam Negative Near IR 780 900 particles nm light source Multiple detectors Color Absorption of light beam if the incident Negative Near IR 780 900 dissolved light wavelengths overlap the absorptive nm light source in t
143. ded ASTM 3977 97 SSC From Sus Sediment Coarse SSC Coarse Method C pended Sedi gt 62um ment bottle Suspended 70331 ASTM 3977 97 55 From Sus Sediment Fine SSC Fine Method C pended Sedi 62um ment bottle Detection limits are determined on a yearly basis by VDCLS using the procedure found in Appendix B of EPA CFR Part 136 7X D Elia C F P A Steudler and Corwin 1977 Determination of Total Nitrogen in Aqueous Sam ples Using Persulfate Digestion Limnol Oceanogr 22 760 764 3 Aspila Agemian and Chau 1976 A semi automated method for the determination of inorganic organic and total phosphate in sediments Analyst 101 187 197 V Valderrama J C 1981 The simulataneous analysis of total nitrogen and total phophorus in natural waters Mar Chem 10 109 122 5 Add on samples whole water samples and the results stored as total concentrations rather than dissolved concentrations 6 BAYT3 container Add on samples is analyzed for 00530 00540 00631 00608 00600 00671 16 II PROJECT ORGANIZATION AND RESPONSIBILITY The organization of the project for the Virginia River Input Monitoring Program is outlined in the diagram below The duties of the individuals are also described below Project Officer Frederick Hoffman Chesapeake Bay Office VDEQ 804 698 4334 Fax 804 698 4032 Principal Investigators Kenneth E Hyer and Douglas L Moyer U S Geologic
144. ded The drainage area for this watershed is 663 mi The location of this monitoring site is lat 37951728 long 78 15 58 NAD27 on State Route 15 in Fluvanna County The Rappahannock River Basin encompasses a land area of approximately 2 848 mi which constitutes about 7 percent of the State of Virginia The river flows from the eastern edge of the Blue Ridge physiographic province through the rolling hills of the Piedmont and Coastal Plain to the Chesapeake Bay and is the second largest contributor of flow to the Chesapeake Bay from Virginia The major cities or towns in the basin include Fredericksburg Warrenton Winchester Culpeper and Orange The Rappahannock River monitoring station USGS station 01668000 is located upstream of Fredericksburg Va This USGS station is at a cableway located 4 3 miles upstream of a VDEQ station TF3 1 Discontinued 3 2001 at the Route 1 bridge data from the VDEQ station is not used in this study The area of the drainage basin upstream from the sampling station is approximately 1 596 mi which is about 56 percent of the Rappahannock River basin Upstream 10 from this station most of the basin is in the uplands of the Piedmont Province and because of the high relief the river produces rapid or flashy streamflow peaks as a result of precipitation The river therefore may carry large loads of suspended solids and other constituents relative to the size of the basin The agricultural land use
145. der all the guidelines For most applications the USGS will conform to ASTM guidelines unless data were specifically collected for drinking water compliance using either EPA Method 180 1 GLI Method 2 or ISO 7027 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 51 Traditionally the USGS has censored data below 2 NTU as not detected less than 2 However improvements in instrument capabilities have resulted in greater reliability at this low end Based on input from instrument manufacturers ASTM has chosen to report data below 1 to the nearest 0 05 unit and to the nearest 0 1 for data ranging between 1 and 10 Because turbidities in this range should be free of appreciable color or settleable materials static methods should provide reasonable comparisons with dynamic methods Before publishing such data study personnel should consider submitting samples of low turbidity water to the NWQL or other laboratory for confirmation of low end resolution and reproducibility Additionally the high end of an instrument s range should be determined Data greater than this value should be censored as greater than the maximum value For dynamic sensors on a submersible sonde cover the optics with a piece of lint free cloth and record the resulting turbidity Confirm this value with the manufacturer s recommendations Qualify data having the maximum value by showing a gt remark code in NWIS Table 6
146. dition to the field and laboratory components of the quality assurance plan there is also in house checking of data that are received from the laboratory All data are logged in as they arrive from VDCLS then later are reviewed for transcription errors and corrected Concentrations below the minimum reporting limit data are considered in the regression model to be equal to the minimum reporting limit as long as fewer than 25 percent of the data are censored The adjusted maximum likelihood estimator AMLE is used in the few cases where censoring is greater than 25 percent Helsel and Cohn 1988 In summations of total nitrogen and total phosphorus from their respective dissolved and particulate constituents the sum is taken to be a value less than the combined minimum reporting limits if both the particulate and dissolved values are censored V V5 lt 1 If just one value is censored the sum is considered to be the uncensored value plus half the minimum reporting limit for the censored value lt V4 V5 However total nitrogen for the time period 1985 1996 is determined as the sum of total kjeldahl nitrogen TKN and nitrate plus nitrite DNOx Censored data handled as follows if DNOx is lt 0 041 mg L then TN TKN else TN TKN DNOx Calculations for all replicate data are also performed with the censored data equal to zero in order to define the range of variance for each constit
147. dity vs ESTIMATOR Annual CIMS data delivery USGS interpretive report describing results by June 2008 Write submit QA QC References Christensen V G Jian Xiaodong and Ziegler A C 2000 Regression analysis and real time water quality monitoring to estimate constituent concentrations loads and yields in the Little Arkansas River south central Kansas 1995 99 U S Geological Survey Water Resources Investigations Report 00 4126 36 p Christensen V G 2001 Characterization of surface water quality based on real time monitoring and regression analysis Quivira National Wildlife Refuge south central Kansas December 1998 through June 2001 U S Geological Survey Water Resources Investigations Report 01 4248 28 p Christensen V G Rasmussen P P and Ziegler A C 2002 Comparison of estimated sediment loads using continuous turbidity measurements and regression analysis abst in Proceedings of Turbidity and Other Sediment Surrogates Workshop April 30 May 2 2002 Reno NV Moyer D L 2005 Quality Assurance Project Plan for the Virginia River Input Monitoring Plan Available upon request to dlmoyer usgs gov or kenhyer usgs gov Sholar C J and Shreve E A 1998 Quality assurance plan for the analysis of fluvial sediment by the northeastern region Kentucky District Sediment Laboratory U S Geological Survey Open File Report
148. dure A or flowthrough chamber Procedure B field measurements as described in 6 0 Procedure A Dynamic measurement Immerse the multi parameter sonde or single turbidity sensor in the water body Procedure B Flowthrough chamber ground water only Secure chamber cover over sonde sensor to form an air tight and water tight seal Discharge the first sample ali quot to waste then open the connection to the flowthrough chamber and pump a sample from the water source to the flowthrough chamber according to instructions in NFM 6 0 3 Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 44 TBY Activate the instrument to display turbidity values in real time Agitate the turbidity sensor to remove bubbles from the optical surface move the sensor up and down or in a circular pattern and or activate the wiper mechanism if available 6 Monitor turbidity readings as described for other field measurements in NFM 6 0 e Allow at least 2 minutes before recording the required number of sequential readings Some instruments may require as much as 10 20 minutes warmup time e Stability is reached if values for three for in situ procedure to five for flowthrough chamber procedure or more sequential readings spaced at regular time increments are within 10 percent 7 Record turbidity readings on the field form and in field notes including the instrument manufacturer and model Use reporting units appropria
149. e double stop cock Teflon bailer 25 Tables 6 4 1 Equipment and supplies used for measuring 5 6 4 2 pH electrodes recommended for water having elevated concentrations of sodium and other monovalent major cations sulfide cyanide and ferric chloride 7 6 4 3 Troubleshooting guide for pH measurement e ee eee seen esten 27 pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 6 4 Revised by George F Ritz and Jim A Collins pH is a primary factor governing the chemistry of natural water systems and is measured routinely in U S Geological Survey USGS studies of water quality The pH of water directly affects physiological functions of plants and animals and is therefore an important indicator of the health of a water system pH A mathematical notation defined as the negative base ten logarithm of the hydrogen ion activity measured in moles per liter of a solution The pH of an aqueous system can be understood as an estimation of the activity or effective concentration of hydrogen ions H affecting that system The theoretical basis of H activity and measurement are described in greater detail in Hem 1989 and in Pankow 1991 By definition pH log 10 H and H 10 gt Logarithmic units are used to express activity because the concentration of in most environmental
150. e 6 3 3 e Ifan instrument cannot be adjusted to known calibration stan dard value develop a calibration curve After temperature com pensation if the percentage difference from the standard exceeds 5 percent refer to the troubleshooting guide section 6 3 4 12 Record in the instrument log book and on field forms e Thetemperature of the standard solution e Theknown and the measured conductivity of the standard solu tion including variation e Thetemperature correction factor if necessary 13 Discard the used standard into a waste container Thoroughly rinse the sensor thermometer and container with deionized water 14 Repeat steps 7 through 13 with the second conductivity standard e The purpose for measuring a second standard is to check instru ment calibration over the range of the two standards e The difference from the standard value should not exceed 5 per cent e Ifthe difference is greater than 5 percent repeat the entire cali bration procedure If the second reading still does not come within 5 percent of standard value refer to the troubleshooting guide in section 6 3 4 or calibrate a backup instrument 15 Record in the instrument log book and on field forms the calibration data for the second standard Do not use expired standards Never reuse standards Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 10 SC Table 6 3 3 Correcti
151. e NWIS data base gt Record the accuracy range of the instrument in the data base if possible Report the accuracy range with the published values Report only those water temperature values that were measured in situ Chapter A6 Field Measurements Temperature Version 2 3 2006 SELECTED REFERENCES American Heritage Dictionary of the English Language 1976 Calibrate Boston Houghton Mifflin Company p 190 American Public Health Association American Water Works Association and Water Environment Federation 2005 Standard methods for the examination of water and wastewater 21st ed Washington D C American Public Health Association p 2 61 to 6 62 ASTM International 2005 Temperature measurement in ASTM Book of Standards v 14 03 July 2005 accessed December 16 2005 at http www techstreet com info astm tmpl Brooklyn Thermometer Company Inc 2005 FAQ How accurate is my thermometer accessed December 16 2005 at http www brooklynthermometer com cgi local SoftCart exe online store scstore sitepages faq 2 4 html L scstoret tytma8290 1135558467 ques4 Hem J D 1989 Study and interpretation of the chemical characteristics of natural water 3d ed U S Geological Survey Water Supply Paper 2254 p 18 ICL Calibration Laboratories Inc 2003 NIST GMP 11 Good measurement practice for assignment and adjustment of calibration intervals for laboratory standards accessed December 16 2005 at
152. e When using a thermistor thermometer wait until the readings stabilize to within 0 2 C then record the median of approxi mately the last five values 5 Remove the temperature sensor from the water rinse it thoroughly with deionized water blot it dry and store it 6 Record the stream temperature on field forms Determine the values as follows e Instill water median of three or more sequential values e For equal discharge increments EDI mean value of subsections measured use median value if measuring one vertical at the centroid of flow e For equal width increments EWI mean or median value of subsections measured Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 17 6 1 3 6 GROUND WATER Measurements of ground water temperature must be made downhole or with a flowthrough system at the end of purging to ensure that the temperature measured accurately represents ambient aquifer water conditions consult NFM 6 0 for guidance Do not report a tempera ture value measured from a bailed ground water sample To measure the temperature of ground water gt Select either the downhole or flowthrough chamber sampling system see NFM 6 0 fig 6 0 4 and record the method used Measure temperature with a thermometer that has been office laboratory certified within the past 12 months and within the temperature range to be encountered 1 Prepare the instruments for either the downh
153. e and conscientious efforts of technical reviewers D A Evans K K Fitzgerald and S C Skrobialowski The editorial and production quality of this report is a credit to I M Collies and L J Ulibarri Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 Chlorophyll Collection and Processing for Fall Line Stations Standard collection procedures are followed ensuring ample volume for sediment nutrient and chlorophyll samples approx 5 liters sample needed After drawing sediment sample draw 500mL sample into amber bottle for chlorophyll filtration and set aside Complete nutrient samples raw and filtered Assemble filter apparatus o Filter flask o Magnetic base and cup o Hand vacuum pump Apply filter to base attach cup moisten filter with DI Gently agitate sample Measure 100mL sample in graduated cylinder and pour into cup Add 10 drops 1mL Magnesium Carbonate solution to sample cup Apply vacuum and filter sample vacuum not to exceed 15 cm Hg 6 in Hg When sample is filtered remove cup Using forceps remove filter and fold in half with particulate material inside Place inside foil sheet Repeat filtration three times placing all filters in same foil sheet and ensuring they are separated within Wrap in larger foil sheet and place label on foil ensuring the number of filters and volume filtered through each is noted on the label Place in whirl pac or Ziploc and put on ice until delivery Clean all equipment with liq
154. e first station is the North Fork Shenandoah River near Strasburg Va USGS station 01634000 and VDEQ station IBNFS010 34 The drainage area for this watershed is 768 mi The location of this monitoring site is lat 38 58 36 long 78 20 10 NAD83 which is at state Highway 55 in Warren County Va The second station is the South Fork Shenandoah River at Front Royal Va USGS station 01631000 and VDEQ 1BSSF003 56 The drainage area for this basin is 1 642 mi The location of this monitoring site is lat 38 54 50 long 78 12 39 NAD83 which is at State Highway 619 in Warren County Va In 2010 a monitoring station was added at Smith Creek near New Market USGS station 01632900 and VDEQ 1 5 7004 60 The drainage area of the watershed is 93 6 mi The location of this monitoring site is lat 38 41 36 long 78 38 35 NAD27 on State Route 620 in Shenandoah County E Description of Streamflow Constituent concentrations within a river change as a function of streamflow and streamflow data are necessary to compute constituent loads A streamgage is currently operated at each of the network monitoring stations these streamgages are operated as a joint network by USGS and VDEQ following USGS protocols Realtime streamflow data are available online at http waterdata usgs gov va nwis rt 12 F Monitoring Parameters and Frequency of Collection Table 2 shows the constituents monitored for this study the detection limits at each la
155. e personnel prior to its release from the laboratory The reviewers judge whether there is a reason for the data to have failed a check If analytical error is suspected re run of the sample is requested Quality assurance monitoring is also performed by the requestor of the analysis whose familiarity with the site may allow them to identify an error that was not apparent to the laboratory personnel If an error is found with the analysis a re run is requested Quality assurance of all materials used in the preservation and containment of water samples is performed by the USGS laboratory Preservation materials such as sulfuric acid and sample bottles are randomly sampled by lot or batch number for any elevated trace metals and major cations and anions that may be present If elevated levels are indeed found in either of these the laboratory conducts additional sampling of the preservation materials and bottles and if necessary recalls them VDCLS participates in a nation wide Standard Reference Sample SRS quality assurance program This program was designed to evaluate the performance of each participating laboratory 29 as well as monitor long term trends in the bias and accuracy of analytical methodologies Samples are prepared at the NWQL Denver CO Samples are prepared by the USGS Branch of Quality Assurance from which they are subsequently distributed to laboratories across the country Results are published twice yearly and
156. e turbidity Most modern turbidimeters will adjust initial sample readings directly into a final reading based on the previous calibration If the meter does not have this capability you will need to read values from a calibration curve constructed previously See step 6 under Benchtop static turbidimeter calibration for instructions on constructing and using calibration curves a Record the very first readings after placement of the sample cell in the measurement chamber If readings are unstable particle settling may be occurring gently re invert the cell 25 times and record at least three readings over a defined time interval for example 30 seconds to 1 minute b Repeat at least twice with fresh sample until three or more sample values fall within 10 percent c Samples that contain significant color should be diluted if using EPA Method 180 1 Results of diluted samples must be qualified with d in the Value Qualifier Code field for data entered into the USGS NWIS database d Report the median of the three or more sequential readings that fall within 10 percent For diluted water samples the measured turbidity must be converted based on the amount of dilution according to the following equation V Vj 5 5 9 where T turbidity of the environmental sample T turbidity of the diluted sample V volume of turbidity free water in the diluted mixture and volume of the environme
157. e within the chamber to the nearest 0 1 C using a calibrated thermometer NFM 6 1 e The temperature inside the chamber should approximate the water temperature e Ifthe two temperatures do not match allow additional time for equilibration of the chamber with the water temperature e Ifthe temperature of the chamber still does not approximate the water temperature the thermistor in the DO sensor might be malfunctioning Compare water temperature measured by the DO meter and a calibrated field thermometer If the two measurements vary by more than 0 2 C the calibration should be discontinued and the DO meter thermistor should be repaired following the manufacturer s recommendations TECHNICAL NOTE Most instrument manufacturers recommend calibrating at temperatures that are at least within 10 C of the ambient water temperature The most accurate calibration will be achieved if the temperature difference between the environmental water and the calibration chamber is minimized as much as possible 5 Use table 6 2 6 section 6 2 5 to determine the DO saturation value at the measured water temperature and atmospheric pres sure If a salinity correction will be applied during calibration consult the instructions in section 6 2 5 and table 6 2 7 6 Following the manufacturer s instructions set or adjust the calibra tion control until the instrument reads a DO saturation value deter mined from oxygen solubility table 6 2 6
158. easurement process For additional information on turbidity measurement see Sadar 1998 U S Environmental Protection Agency 1999 and the literature provided by instrument manufacturers TECHNICAL NOTE 1 Variability in measurements caused by instability in light sources high particle densities or color can be reduced by the use of multiple detectors at different angles Such ratiometric instruments compute the turbidity value using a ratio of the light received by the different detectors Furthermore because turbidity is an optical measurement the absorption of light by colored particles or by a colored matrix can cause a reduction in the apparent turbidity The negative effect from color is minimized by using near infrared light frequencies as the light source tables 6 7 1 6 7 3 or ratiometric techniques Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 9 DATA STORAGE 6 7 1 B To ensure that USGS turbidity data can be understood and interpreted properly within the context of the instrument used and site conditions encountered data from each instrument type will be stored and reported in the National Water Information System NWIS using parameter codes and measurement reporting units that are specific to the instrument type with specific instruments designated by the method code The respective measurement units most of which also are in use internationally are listed and defined in table 6
159. ected conductivity value adjusted to 25 actual conductivity measured before correction and tn water temperature at time of C measurement MEASUREMENT 633 In situ measurement generally is preferred for determining the con ductivity of surface water downhole or flowthrough chamber mea surements are preferred for ground water Be alert to the following problems if conductivity is measured in an isolated discrete sample or subsample gt The conductivity of water can change over time as a result of chemical and physical processes such as precipitation adsorption ion exchange oxidation and reduction Do not delay making conductivity measurements Field conditions rain wind cold dust direct sunlight cause measurement problems Shield the instrument to the extent possible and perform measurements in a collection chamber in an enclosed vehicle or an on site laboratory For waters susceptible to significant gain and loss of dissolved gases make the measurement within a gas impermeable container Berzelius flask fitted with a stopper Place the sensor through the stopper and work quickly to maintain the sample at ambient surface water or ground water temperature Avoid contamination from the pH electrode filling solution Measure conductivity on a separate discrete sample from the one used for measuring pH in a flowthrough chamber position the conductivity sensor upstream of the pH electrode
160. ed for this check measurement Follow the manufacturer s instructions for readout of turbidity value and record the turbidity of the calibrant used and the turbidity value measured in the calibration logbook If readings are not within specifications for the indicated range recalibrate the instrument for the turbidimeter using accepted calibration turbidity solutions Most turbidimeters will correct initial sample readings directly into a final reading based on the stored calibration If the meter does not have this capability take the values from a previously constructed calibration curve For samples with turbidity less than 40 turbidity units Measure sample turbidity immediately or as soon as possible upon sample withdrawal a If discrete subsamples are to be taken from a churn splitter or other sample compositing device remove samples for turbidity measurement along with other whole water samples Avoid pouring the sample into a cuvette from a bottle if possible If not possible then invert the bottle 25 times using 1 second inversion cycle and pour off the sample immediately to capture suspended particles Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 36 TBY b Fordrinking water use an instrument that complies with EPA Method 180 1 or GLI Method 2 Measurements are reported in NTU or NTRU for EPA 180 1 or in FNMU for GLI Method 2 See table 6 7 4 to select the appropriate parameter c
161. eeded to accurately estimate loads using the log linear regression model selected for this study Emphasis was placed on sampling throughout the range in storm conditions that existed throughout the sampling period Currently 20 samples per year are needed to accurately estimate loads using the log linear regression model selected for this study and utilizing the data previously collected for this project stations will have 20 water quality samples collected each year These 20 samples will be comprised of 12 routine samples and 8 stormflow samples In addition to the once per month routine samples up to 2 storm samples may be collected on either the rise peak or fall of a given storm hydrograph This allows for the identification of the variability associated with each water quality constituent over a wide range of stormflow events Appendix 1 shows an example of the record of field data planned including quality assurance data This form is also used by field personnel to document that the sample was collected This record is kept for each of the stations 13 G Continuous Water Quality Monitoring In 2007 continuous water quality monitors were added to the existing RIM project at the James River at Cartersville Rappahannock River at Fredericksburg and Pamunkey River near Hanover RIM stations The Rappahannock River monitor was discontinued in 2009 In April 2010 a continuous water quality monitor was deployed on Smith Creek These YS
162. eese en sten 31 6 2 4 Reporting eon aee ea Eos 33 6 2 5 Correction factors for oxygen solubility and salinity ra ea aee aene 33 Selected references 46 Acknowledgments e eeteeesee eee a inre 48 Illustrations 6 2 1 Graph showing factors used to correct atmospheric pressures adjusted to sea 1 1 12 Tables 6 2 1 Equipment and supplies for the amperometric and luminescent sensor methods of dissolved oxygen MH 7 6 2 2 Factors used to correct atmospheric pressures adjusted to sea 12 6 2 3 Troubleshooting guide for amperometric instruments 24 6 2 4 Equipment and supplies for the spectrophotometric method of dissolved oxygen determination 26 6 2 5 Equipment and supplies for the iodometric Winkler method of dissolved oxygen determination 30 6 2 6 Solubility of oxygen in water at various temperatures PLESSUPES I n 35 6 2 7 Salinity correction factors for dissolved oxygen in water based on conductivity ceeeeeee eee eee 41 Any use of trade product or firm names is for descriptive purposes on
163. eference solution despite differences among the designs The calibration process provides a common point for standardization and if turbidity were an inherent physical property then measurements of environmental waters would be expected to have similar numerical values for any instrument However the varying particle and color characteristics of environmental waters differ fundamentally from formazin crystals This has led manufacturers to develop calibration solutions that in some cases are tailored to specific instruments potentially increasing the magnitude of error if solutions are used improperly Where turbidity data are to be compared within or among data collection projects the consistent use of sampling calibration and measurement equipment and techniques is necessary The USGS follows conventions for turbidity determination established by ASTM International 20032 which defines three levels of calibration solutions calibrants Reference Turbidity solutions Calibration Turbidity solutions and Calibration Verification solutions or solids gt The Reference Turbidity solution is a calibrant that a skilled analyst synthesizes reproducibly from traceable raw materials All other calibrants are traced back to this solution The reference standard for turbidity is formazin made from scratch see below for preparation instructions a polymer with repeating units of gt Calibration Turbidity solution
164. emperature FNU 2200 3000K 150 7027 90 degree detection angle D near infrared LED light source wavelength 860 30 t Drinking water Turbidity 0 1 000 ratiometric not required Ambient surface and NTU ground waters White light process stream tungsten filament or wastewaters wavelength 400 680 nm FNRU 1S0 7027 near infrared LED light source Yes wavelength 860 30 dE Turbidity 0 4 000 turbidity ratiometric data range correction needed NTRU N White light tungsten filament or LED light source wavelength 400 900 nm FBU FNMU Backscatter or multibeam near infrared LED light source wavelength 860 30nm Turbidity 10 10 000 color assumed predominant Alternative technologies suggested BU NTMU Backscatter or multibeam white light tungsten filament or LED light source wavelength 400 900 nm Figure 6 7 2 Decision tree to determine appropriate instrumentation designs for intended turbidity measurements Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 15 Decision Considerations considerations 4 and 5 are not shown in fig 6 7 2 l Is the study regulatory in natu
165. en particle densities are high Instruments that utilize backscatter detection also can help compensate for such effects at high turbidities Backscatter is particularly important above 1 000 units The effect of particle size should be considered too Positive effects on turbidities for water sources with predominantly large or small particle sizes can be minimized with careful consideration of the study objectives the water source and instrument requirements Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 16 TBY 3 5 Is the water source colored by dissolved or particulate materials and should the color be part of the measured turbidity Color in water samples from dissolved or particulate materials or both can cause a negative effect Sutherland and others 2000 on measured turbidity table 6 7 1 In some cases it could be desirable to quantify this decrease by using an instrument with a broad spectrum or white light source that would be sensitive to color changes Alternatively when measuring changes in turbidity that are unrelated to color instruments with a near infrared light source should be used Will the measurement be done by dynamic means or by a benchtop measurement of samples removed from the source In most cases it is preferable to measure turbidity directly within the water source or in a pumped sample dynamically rather than taking a sample from which an aliquot must then be me
166. ended sediment can be a source of measurement error Trecord such conditions in the field notes gt If sediment concentrations are heavy measure conductivity on both unfiltered and filtered subsamples and record both values on the field form Ifthe conductivity value differs significantly between the filtered and unfiltered samples report the filtered value as sample conductivity and identify it as a filtered sample 1 Calibrate the conductivity instrument system at the field site 2 Select the sampling method see NFM 6 0 and collect a represen tative sample 3 Withdraw a homogenized subsample from a sample splitter or compositing device Rinse the sample bottles three times with the sample trinse them with sample filtrate for filtered samples 4 Rinse the conductivity sensor the thermometer liquid in glass or thermistor and a container large enough to hold the dip type sen sor and the thermometer a First rinse the sensor the thermometer and the container three times with deionized water b Next rinse the sensor the thermometer and the container using sample water 5 Allow the sensors to equilibrate to sample temperature then dis card the used sample water Pour fresh sample water into a con tainer holding the sensor and the thermometer When using a dip type sensor do not let the sensor touch the bottom or sides of the measuring container Specific Electrical Conductance Version 1 2
167. ended solids samples Nutrients samples are filtered in the field using an in line 0 45 um Gelman capsule filter All samples are preserved on ice and taken to VDCLS on the same day if possible or as soon as feasible NOTE Samples prior to January 15 1994 were filtered in the VDCLS laboratory After that date field filtering using the Gelman filter was instituted as part of the procedure Because of variations in flow conditions width of each streambed and differences in cross sectional morphology sampling procedures between all rivers differ Protocols were developed for each site outlining where samples are to be taken in the cross section what type and size of sampler to use how samples are to be labeled and the number of samples to collect in order to ensure that all personnel responsible for sampling use the correct procedures Field parameters pH specific conductance dissolved oxygen turbidity and water temperature are collected at alternating stations along the stream channel cross section These parameters are collected using a YSI multi parameter field meter and following standard U S Geological Survey protocols Appendix 4 24 V SAMPLE CUSTODY Samples are collected in plastic cubitainers labeled using a VADEQ tag immediately put on ice and transported to the VDCLS laboratory Hydrochloric acid and sulfuric acid are used to preserve the dissolved organic carbon and total phosphorus samples respectively At th
168. ent system and chemical and microbiological equilibria within the sample pH measurements must be completed and recorded as soon as possible after removing the sample from the environmental medium When entering the pH value for the site into the NWIS database ensure that the method code selected correctly corresponds to the method that was used for the pH measurement gt On field forms electronic or paper and in the pH meter electrode logbook record pH calibration and environmental measurements to 0 01 standard pH units gt Inthe USGS NWIS database report pH values to the nearest 0 1 standard pH unit unless study and data quality objectives dictate otherwise and equipment of the appropriate precision and accuracy has been used 6 4 SELECTED REFERENCES American Public Health Association American Water Works Association and Water Environment Federation 2001 Standard methods for the examination of water and wastewater 20th ed Washington D C American Public Health Association p 4 65 to 4 69 Barnes Ivan 1964 Field measurement of alkalinity and pH U S Geological Survey Water Supply Paper 1535 H 17 p Bates R G 1973 Determination of pH Theory and practice 2d ed New York John Wiley 479 p Beckman Instruments Inc 1986 The Beckman handbook of applied electrochemistry Fullerton Calif Beckman Instruments Inc 86 p Bellerby R G J Turner D R Millward G E and Worsfold P J 1995 Shipb
169. ents Turbidity Version 2 1 9 2005 12 TBY must be diluted before measuring For studies involving the measurement of turbidity in finished drinking water either EPA Method 180 1 GLI Method 2 or Hach Method 10133 must be used This requirement commonly is applied when determining ground water turbidity in water from wells used for human consumption TECHNICAL NOTE 3 One other method ISO 7027 International Organization for Standardization 1999 has been defined for waters with low turbidity and is in use in Europe and elsewhere however as of 2003 ISO 7027 had not been accepted by USEPA for compliance with drinking water regulations in the United States USEPA approved methods generally are not required when providing data for regulatory purposes in accordance with the Clean Water Act U S Environmental Protection Agency 2002a For example nonregulatory methods can be used to determine changes in turbidity of surface water resulting from resource management actions or to correlate turbidity with regulated constituents such as suspended sediment Uhrich and Bragg 2003 nutrients or bacteria Christensen and others 2000 For such data collection efforts it may be possible to use alternative instrument designs that are targeted towards specific study objectives and that will accommodate the range of natural conditions that occur in the water body Before selecting a methodology and the corresponding instrumentation det
170. er specified temperature pressure and salinity at http water usgs gov software dotables html accessed Apr 27 2006 Check DO meter calibration at each field site In addition amperometric instruments should be recalibrated each time after a meter has been powered off Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 12 DO Table 6 2 2 Factors used to correct atmospheric pressures adjusted to sea level NGVD National Geodetic Vertical Datum of 1929 Elevation of weather station Value to subtract in feet NGVD millimeters of mercury 0 0 1 000 27 2 000 53 3 000 79 4 000 104 5 000 128 6 000 151 8 000 prre 7 500 E 4 7 000 F 4 6 500 4 6 000 4 5 500 4 m 5 000 E 3 4 500 F 4 4 000 E 4 5 3 500 E 4 3 000 4 5 2 500 4 2 000 4 ai 1 500 E j 1 000 E 4 500 4 oL 3 500 4 1 000 40 20 0 20 40 60 80 100 120 140 160 180 200 VALUE SUBTRACT FROM ATMOSPHERIC PRESSURE IN MILLIMETERS OF MERCURY Figure 6 2 1 Factors used to correct atmospheric pressures adjusted to sea level Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 13 Although the salinity correction can be made either during calibration or after measurement the pre
171. erature equilibration Do not contaminate standards with sample water a Check the temperature of the water flowing into the bucket against that of standards b Check that the thermometer usually a thermistor function in the conductivity meter has been certified within the past 4 months for the temperature range to be measured e After calibration rinse the conductivity and temperature sen sors thoroughly with deionized water 2 Install the conductivity and temperature sensors e Downhole system Lower the conductivity and temperature sensors to the sampling point followed by the pump Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 17 a Remove any air from the system by agitating the conductivity sensor up and down under the water read the instrument display b Repeat this procedure until rapid consecutive readings are approximately the same e Flowthrough chamber system Install the chamber system as close to the well as possible and shield the system from direct sunlight a Position the conductivity sensor upstream from the pH electrode b Direct flow to the chamber after an initial discharge to waste to clear sediment from sample line c Release any air trapped in the chamber d Agitate the conductivity sensor up and down under the water to remove air from system Rapid consecutive readings should be about the same 3 During purging table 6 0 1 in
172. ermine if USEPA compliant methodologies are necessary Given the breadth of applications for measuring turbidity no particular sampling consideration can be defined as the most important in all cases however consistency of instrument types and calibration procedures within monitoring programs or among individual projects is one of the most important aspects to consider when designing a data collection program that will include turbidity Nephelometry the measurement of light scattering using a light detector 90 degrees from the incident light USEPA 1999 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 13 Decision Considerations for Instrument Selection Numerous factors are involved when deciding on the type s of equipment that are appropriate for a given study major consideration in the selection of a turbidity instrument is whether turbidity will be measured under static or dynamic conditions Water samples that are removed from the source and are measured with benchtop meters are considered static Submersible sensors allow turbidity measurement under dynamic water conditions using either instantaneous profiling techniques or a deployed instrument for continuous monitoring Measurements taken under static conditions compared to those taken under dynamic conditions differ primarily because static measurement techniques do not completely account for particle settling whereas dynamic measuremen
173. es d Ifa field thermistor is found to be within 0 2 C of the calibration thermometer set it aside for calibration checks at higher temperatures 5 Repeat steps 1 4 in 25 C and 40 C water Keep the bath tempera ture constant Check the thermistors at two or more additional intermediate temperatures for example 15 C and 30 C 6 Tag acceptable thermometers as office laboratory certified with calibration date and certifier s initials Chapter A6 Field Measurements Temperature Version 2 3 2006 12 T To calibrate field thermometers when a commercial refrigerated water bath is not available A For the 0 C calibration 1 Freeze several ice cube trays filled with deionized water 2 Fill a 1 000 milliliter mL plastic beaker or Dewar flask three fourths full of crushed deionized ice Add chilled deionized water to the beaker Place the beaker of ice water mixture in a larger insulated container or Dewar flask Place the calibration thermom eter into the ice water mixture and make sure that the temperature is uniform at 0 by stirring and checking at several locations within the bath 3 Precool the sensor of the field thermometer s to 0 C by immersing in a separate ice water bath 4 Insert the field thermometer s into the ice water mixture Position the calibration and field thermometers so that they are properly immersed and so that the scales can be read Periodically stir the ice water m
174. es Document any changes made to standard USGS procedures Rhodazine D a colorless reduced dye is a proprietary product of CHEMetrics Incorporated and constitutes less than 1 volume percent of solution in the ampoule Additional constituents in the ampoule are water diethylene glycol tris hydroxymethyl aminomethane and potassium hydroxide Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO S5 AMPEROMETRIC 6 2 1 LUMINESCENT SENSOR METHODS The amperometric and luminescent sensor methods are appropriate for routine measurement of DO concentrations under most of the field conditions encountered by USGS data collection personnel Calibra tion procedures are similar for these methods gt The amperometric method has been the most commonly used field method for measuring DO in water for USGS data collection efforts The DO concentration is determined using a temperature compensating meter connected to a polarographic membrane type of sensor e The method is relatively simple to use and is well suited to making discrete or continuous in situ measurements of DO concentration in surface water or ground water e Method performance can be negatively affected by calibration drift by loose wrinkled or damaged membranes or by sen sor contact with hydrogen sulfide Unfortunately poor perfor mance can occur without any indications from the instrument readings gt The luminescen
175. es instruments are designed to operate in different modes for example ratiometric or non ratiometric Such instruments are listed multiple times in the spreadsheet at http water usgs gov owq turbidity codes xls accessed 9 30 2005 corresponding to different parameter codes to distinguish their different settings Be careful to document all instrument settings and dilution factors and use parameter codes and method codes appropriate for instrument settings For data storage in NWIS samples with noticeable sand or coarse materials that were measured by static techniques must be qualified as Estimates with an in the Remark code and diluted samples must be entered with a in the Value Qualifier Code field gt USGS personnel Do not use parameter codes 00076 and 61028 These codes are reserved for historical turbidity data for which an equipment method cannot be assigned Guidelines for reporting turbidity measurements to the nearest acceptable digit according to EPA Method 180 1 GLI Method 2 ASTM and ISO 7027 methods are listed in table 6 7 6 The indicated values represent the least significant digit in the measurement Reported turbidity values should be rounded to this level of precision For example a value of 43 12 units displayed by an instrument would be reported as 45 under USEPA guidelines but as 43 under ASTM guidelines In contrast a value of 13 42 units displayed by an instrument would be reported as 13 un
176. etetramine chemicals or Instrument specific polymer solutions containing styrene divinylbenzene beads Sample cells cuvettes clear colorless glass supplied from instrument manufacturer Inert dry gas for example nitrogen and gas delivery apparatus tanks must be fitted with regulators and filter Sample bottle preferably an amber bottle that does not sorb suspended material Silicon oil optical grade with same index of refraction as sample cells supplied by instrument manufacturer Paper tissues extra lint free Turbidity free water deiononized water filtered through a lt 0 2 mm filter membrane with precision sized pores Bottle to hold turbidity free water cleaned and rinsed three times with filtered water Volumetric flask Class A 100 mL or 500 mL Volumetric pipet Class A 5 0 mL and pipet filler See text figure 6 7 2 and table 6 7 3 for description of appropriate instrument types Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 Before field use of water quality instruments become familiar with the manufacturer s instructions for calibration operation and maintenance The maintenance program must include Regular cleaning of optical surfaces Use a lint free cloth soft toothbrush or paintbrush and deionized water for cleaning optical surfaces Exercise care so as not to damage optical surfaces Optical surfaces of some instruments may be more eas
177. f concentration ranges White and others 1990 used a portable Milton Roy Minispect 10 battery powered spectrophotometer Any spectrophotometer of equal or better quality can be used if it can accept a 13 mm diameter cell and is adjustable to a wavelength of 555 nanometers 6 2 2 8 CALIBRATION AND INTERFERENCES Dissolved oxygen is measured as percent absorbance by the spectropho tometer gt Acalibration chart is provided in each CHEMetrics kit along with a regression formula to convert absorbance to micrograms per liter of DO for use with the spectrophotometer No other standards are provided CHEMetrics photometers are pre calibrated for direct readout The CHEMetrics kit contains a blank ampoule used to zero a spectrophotometer or the CHEMetrics V 2000 photometer The CHEMetrics V 1000 photometer is supplied with a Zeroing ampoule gt Interferences from total salinity major dissolved inorganic species dissolved gases or temperature are negligible Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 20 27 The spectrophotometric method is affected by the presence of reducible inorganic species such as chlorine ferric and cupric ions and hexavalent chromium resulting in high biased DO readings The presence of cupric copper and ferric iron at less than 50 micrograms per liter ug L cause a bias of less than 1 ug L at concentrations of 100 ug L cupric copper causes a bias of 5 ug
178. ferred USGS method is to apply salin ity correction factors after calibration and measurement recali bration is necessary for each field variation in salinity if the correction is made during calibration For salinity correction procedures see section 6 2 5 Calibration procedures The three procedures described below are for a one point calibration 100 percent saturation of a DO system The iodometric method for DO measurement described in section 6 2 3 can be used to check the calibration of these instruments Record all calibration information in instrument log books and copy calibration data onto field forms at the time of calibration Procedure 1 Air calibration chamber in air and Procedure 2 Calibration with air saturated water can be used with minor modifications for either amperometric or luminescent sensor instruments gt Procedure 3 Air calibration chamber in water is appropriate only for the amperometric method gt Many amperometric DO sensors require the meter to be turned on for 10 to 15 minutes before calibration and use to stabilize the probe Refer to the manufacturer s instrument specific guidelines for the requirements of your instrument Procedure 1 Air calibration chamber in air This procedure is similar to Procedure 3 Air calibration chamber in water which commonly is used for amperometric instruments except that the calibration chamber is in air rather than in water This calibra tion met
179. figured to measure water temperature turbidity specific conductance and pH at 15 minute intervals this interval is commonly referred to as producing continuous data The instrument will be connected to data logging and telemetry equipment that will transfer all data to the USGS office in Richmond VA where the data will be displayed on the internet for access by all interested individuals Following the initial deployment approximately monthly maintenance visits will be performed on the continuous water quality monitor to clean the equipment and check the calibration of the sensors In field recalibration will be performed during these monthly maintenance visits as necessary following the equipment tolerances as specified by the monitor manufacturer and those outlined by Wagner and others 2000 Following the monthly maintenance visit the maintenance data will be used to determine whether the monitoring equipment was subject to bio fouling or calibration drift If either of these conditions were observed to be outside the SOP tolerances the continuous water quality record may be shifted to correct these data At the conclusion of each water year the data will be reviewed for accuracy all shifts will be checked the quality of the data will be rated as excellent good fair or poor a station analysis for the water year will be prepared and the finalized data will be published in the Annual Virginia Water Science Center Data Report By fol
180. flect the possible bias in the Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 27 data For input to the USGS NWIS database the results would be coded with an E remark indicating the value is an Estimate only cuvettes used for calibrating static turbidimeters are identical to those used in the meter when taking a turbidity reading gt Submersible meters collect data by immersing a turbidity sensor in the sample media but are calibrated using a separate chamber that allows the sensor to be immersed in the calibrant Benchtop static turbidimeter calibration The calibration instructions and procedures that follow are general and should be modified to apply to the instrument being used check manufacturer s instructions Refer to table 6 7 5 for a list of supplies commonly used for turbidity measurement To calibrate a benchtop turbidimeter 1 Prepare formazin suspensions as described above Allow stock solutions to come to room temperature Calibrate each instrument range using at least two calibrant concentrations and three or more if the instrument allows it Use calibrant solutions that bracket the range of the turbidity anticipated in the sample solution Prepare dilute calibrant fresh from the stock at the time of use after dilution the stock suspension is stable only for a few hours e Formazin based calibrants should be resuspended by inverting the calibr
181. for temperature equilibration of buffer solutions Waste disposal container pH meter electrode logbook for recording calibrations maintenance and repairs We NS NC US MSDS for all pH buffers and other reagents to be used This list pertains to single parameter instruments for measuring pH Refer to NFM 6 8 for information on and general use of multiparameter instruments This list may be modified to meet the specific needs of the field effort CAUTION Keep Material Safety Data Sheets MSDS readily available and refer to them to ensure that pH buffers or other chemicals are handled safely Chapter A6 Field Measurements pH Version 2 0 10 2008 6 pH 6 4 1 pH METERS A pH meter is a high impedance voltmeter that measures the very small direct current potential in millivolts mV generated between a glass pH electrode and a pH reference electrode The potentiometric measurement is displayed as a pH value The meter uses potentiometric differences to generate these pH values and is programmed with 1 the ideal Nernstian response relating hydrogen ion activity concentration and electrical response 59 16 mV unit pH and 2 an automatic temperature compensation ATC factor Since the ideal Nernstian slope response from the electrode varies with temperature the meter s software adjusts the slope to be in accordance with the Nernst equation at the corresponding environmental temperature during ca
182. g curve is then used to calculate discharge from the stream stage A one year pilot deployment of a turbidity probe on the James River during 2004 demonstrates a statistically significant correlation p 0 01 between turbidity and suspended sediment concentrations Figure 1 James River at Cartersville 2004 Water Year 500 400 300 200 Suspended Sediment mg L 100 0 0 100 200 300 Turbidity NTU Figure 1 Relation between turbidity and suspended sediment on the James River at Cartersville VA 2004 Continuous water quality monitoring protocols continuous water quality monitoring operations in the USGS are to be performed according to the USGS standard methods for the operation of this equipment These standard operating procedures have been thoroughly documented by Wagner and others 2000 in their Water Resources Investigations Report entitled Guidelines and Standard Procedures For continuous Water quality Monitors Site Selection Field Operation Calibration Record Computation and Reporting Because these published USGS Standard Operating Procedures SOP will be followed during this study only a summary of these procedures will be outlined below and an internet link to the full SOP Manual is provided in the references section The continuous water quality monitor likely a YSI Model 6920 multi parameter monitor will be deployed at three of the existing River Input Monitoring Stations and con
183. glasses and apron Waste disposal container White background sheet Deionized water maximum conductivity of 1 uiS cm Bottle squeeze dispenser for deionized water Thermometer calibrated see NFM 6 1 for selection and calibration criteria SC OS Pocket altimeter barometer calibrated Thommen model 2000 equivalent Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 31 MEASUREMENT 6 2 3 Measure DO on at least two subsamples for quality control Results of two iodometric titrations should agree within 0 1 mg L If they do not agree repeat the titration on a third subsample Follow steps 5 and 6 to perform the iodometric titration in duplicate If the purpose is to check calibration of an amperometric or luminescent sensor instrument start at step 1 and continue to the end 1 2 000 mL beaker with deionized water that is near DO satu ration The water temperature should be close to the ambient field or laboratory temperature 2 Prepare the DO instrument for operation according to the manu facturer s instructions 3 Place the DO sensor in a beaker of distilled water With a magnetic stirrer maintain a velocity of at least 1 ft s past the DO sensor 4 Monitor the DO concentrations of the deionized water with the DO instrument and record the value after the readings have stabilized 5 Carefully fill two biochemical oxygen demand BOD
184. gorithms can provide a smoother signal than simple instantaneous measurements however because the algorithms may not be published these data must be used with care and in consideration of the data quality objectives of the study Note that if the instrument uses signal averaging to smooth the data output the instrument response to changes in turbidity readings can be slowed Select the output you desire in accordance with study objectives and data storage and transmittal requirements Maintenance of Turbidity Instruments The equipment and supplies commonly used for field measurement of turbidity are listed in table 6 7 5 These include supplies generally needed for the maintenance storage and cleaning of the selected instrument Routine maintenance of turbidity instrumentation is critical particularly for continuously deployed dynamic applications Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 19 Table 6 7 5 Equipment and supplies used for measuring turbidity Modify this list to meet the specific needs of the field effort Abbreviations lt less than or equal to mm millimeter mL milliliter Turbidimeter spectrophotometer or submersible sensor instrument such as a multiparameter instrument with a turbidity sensor Calibration turbidity stock solutions and standards Formazin stock suspension commercially obtained or prepared from scratch with hydrazine sulfate and hexamethelen
185. gton D C U S Environmental Protection Agency Office of Water EPA 815 R 99 010 variously paged U S Environmental Protection Agency 2002a Federal Water Pollution Control Act as amended through P L 107 3 3 Nov 27 2002 33 U S C 1251 et seq accessed March 25 2004 at http www epa gov region5 water cwa htm U S Environmental Protection Agency 2002b Federal Register Volume 67 No 209 Section October 29 2002 p 65888 65902 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 55 U S Geological Survey variously dated National field manual for the collection of water quality data U S Geological Survey Techniques of Water Resources Investigations book 9 chaps A1 A9 available online at http pubs water usgs gov twri9A Wagner R J Mattraw H C Ritz G F and Smith B A 2000 Guidelines and standard procedures for continuous water quality monitors Site selection field operation calibration record computation and reporting U S Geological Survey Water Resources Investigations Report 00 4252 53 p accessed March 25 2004 at http water usgs gov pubs wri wri004252 Wells M C Magaritz Mordeckai Ameil A J Rophe Benjamin and Ronen Daniel 1989 Determination of in situ metal partitioning between particulate matter and ground water Naturwissenchaften v 76 no 12 p 568 570 Wilde F D and Radtke D B August 2005 General information and guide
186. h DIW a Use a syringe or squeeze bottle to partially fill the pH electrode chamber with DIW b With a syringe remove the DIW from the pH electrode chamber c As a result of changes in pressure temperature and evaporation visible crystals may form in the pH electrode If these are present continue to flush with DIW until all the crystals have been dissolved and removed from the pH electrode 3 Fill the electrode with fresh filling solution Flush the electrode chamber with fresh filling solution using a syringe or a plastic squeeze bottle a Partially fill the pH electrode chamber with the filling solution b Tiltthe pH electrode so that the filling solution will contact all of the internal electrode surfaces c Remove and discard the filling solution to a waste container d Refill the electrode chamber with fresh filling solution until the filling solution level is just below the fill hole Be sure to use the appropriate type and molarity of filling solution e Rinse any excess filling solution from the outside of the electrode with DIW 4 After following the reconditioning procedures retest the electrode If the procedures fail to remedy the problem discard the electrode pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 13 ELECTRODE STORAGE 6 4 2 Electrodes must be clean before they are stored for any length of time Refer to the manufacturer s instructions for the proper short term used
187. he expected life of the thermometer gt Each thermometer that passes the accuracy check must be tagged with the date of calibration Thermometers that do not pass the accuracy check must be repaired if possible or else discarded or otherwise retired from use Theannual calibration of field thermometers can be performed in the office laboratory or by an NIS T accredited commercial laboratory To calibrate a thermometer check its readings across a range of temperatures as described below in the instructions for water bath calibration procedures Temperature checks must bracket and include points that represent the temperature range expected to be encountered in the field EXCEPTION Thermistors in continuous water quality monitors can be field checked annually or more frequently if necessary with a nonmercury NIST certified or NIST traceable thermometer Fully submerge the bulb and liquid column if using a total immersion liquid in glass thermometer Keep calibration and field temperature sensors thermistor or liquid in glass type submerged throughout the calibration process Record thermometer readings throughout the bath warming and cooling periods and while keeping the water stirred or otherwise circulated thermistor readings will be recorded with greater frequency Check meter batteries periodically for proper voltage when using a thermistor type thermometer Temperature Version 2 3 2006 U S Geo
188. he instrument measurement chamber Be sure that sample cells are index marked to indicate orientation Match orientation so that cells yield the same value when light passes through Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 37 4 Determine the measured turbidity value of the sample directly from the instrument scale or by using the instrument value and calibration curve as is appropriate for the instrument being used For samples with less than 1 turbidity unit see TECHNICAL NOTE 6 under step 4d a Record the very first readings after placement of the sample cell in the measurement chamber If readings are unstable then particle settling may be occurring If so gently re invert the cell 25 times and record at least three readings over a short defined time interval for example 30 seconds to 1 minute b Repeat at least twice with fresh sample until three or more sample values fall within 10 percent c Samples that contain significant color should be diluted if using EPA Method 180 1 for samples with turbidity greater than 40 units see below For samples including drinking water with turbidity greater than 40 turbidity units step 3 Results of diluted samples must be qualified with a d in the Value Qualifier Code field for data entered into the USGS NWIS database d Report the median of the three or more sequential readings that fall within 10 percent TECHNICAL NO
189. he spectra within the sample matrix Multiple detectors matrix Particle size Wavelength dependent Large e Scatter long wavelengths of light more Positive for near IR White light broad particles readily than small particles light source 820 spectrum light 900 nm source Small e Scatter short wavelengths of light more Positive for broad Near IR 780 particles efficiently than long wavelengths spectrum light 900 nm light source source such as white light Particle Increases forward and backward scattering Negative Multiple detectors Density of light at high densities Backscattering Table 6 7 2 Sampling interferences and their expected effect on turbidity measurement Positive a positive effect produces a disproportionately high measurement Negative a negative effect produces a disproportionately low measurement Direction of effect Interference Effect on the measurement on the measurement Stray light Increases apparent light scatter Positive B 5 ses i ubbles from Increases apparent light scatter Positive entrained gases Contamination of Increases apparent light scatter Positive calibrants Optical sensor Particularly with dynamic fouling or instruments scratching Possible beam blockage 8 Positive Possible scratches on optical surfaces Bubbles Increases apparent light scatter Positive Scratches on cuvette Increases apparent l
190. henever the pH electrode is exposed to conditions such as those listed on table 6 4 2 this information should be recorded in the pH meter electrode logbook and documented in field notes pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 9 pH BUFFER SOLUTIONS 6 4 1 C pH buffer solutions buffers are ionic solutions that are used to calibrate the pH instrument system Buffers maintain constant pH values because of their ability to resist changes to the specific pH value for which they are produced Measurements of pH are only as accurate as the buffers used to calibrate the electrode gt Use only buffers that have been certified traceable to an NIST standard reference material P Select the buffer molarity that is appropriate for the ionic strength of the water to be measured and the instrument system that will be used For pH measurements of dilute waters with conductivities less than 100 uS cm use of buffers having lower than standard molarity and a low ionic strength pH electrode is recommended refer to section 6 4 3 B For pH measurements in high ionic strength waters with conductivities greater than 20 000 uS cm use of buffers having a higher than standard molarity is recommended refer to section 6 4 3 C gt Label pH buffer containers with the acquisition date and the expiration date Copy the expiration date and the buffer lot number onto any reagent containers into which the buffer is tra
191. here is a quality control section that addresses a assessing laboratory performance and b assessing analyte recovery and data quality Most analytical procedures used are referenced in Chemical Analysis for Water and Wastes USEPA 600 4 79 020 Environmental Protection Agency 1979 and Standard Methods for the Examination of Water and Wastewater 17th ed edited by Clesceri et al 1989 USGS Sediment Laboratory in Kentucky The quality assurance practices of the USGS sediment lab are documented in the Open File report entitled Quality Assurance Plan for the Analysis of Fluvial Sediment by the Northeastern Region Kentucky District Sediment Laboratory OFR 98 384 by C J Sholar and E A Shreve 1998 Included in this publication are analytical methods development procedures standard quantitative analysis techniques instrumental techniques laboratory quality control quality assurance monitoring documentation summary and evaluation of data and material evaluation Quality assurance of analytical results received from the participating laboratories incorporate both quality control and quality assurance monitoring Quality control monitoring is accomplished through the use of a personal and a computerized data review Several computer checks are made which flag a possible error in analysis These flags are documented on the analytical report specific to each sample The completed analytical report is then reviewed by NWOQL quality assuranc
192. hod is most commonly recommended by manufacturers of amperometric instruments Calibration chambers are either built into the instrument case or are provided as separate components by the manufacturer Use the calibration chamber provided or recom mended by the manufacturer 1 Wet the inside of the calibration chamber with water Then pour out the water but leave a few drops Remove any water droplets on the sensor membrane and insert the sensor into the chamber this ensures 100 percent humidity 2 If using an amperometric instrument allow 10 to 15 minutes for the DO sensor and the air inside the calibration chamber to equili brate Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 Using your calibration pocket altimeter barometer read the ambi ent atmospheric pressure checked to the nearest 1 mm of mercury Measure the temperature in the calibration chamber and observe the readings until the instrument stabilizes Read the temperature to the nearest 0 1 C The temperature inside the chamber should approximate the water temperature measured with a calibrated thermometer TECHNICAL NOTE FOR AMPEROMETRIC INSTRUMENTS Most instrument manufacturers recommend calibrating at temperatures that are at least within 109C of the ambient water temperature The most accurate calibration will be achieved if the temperature difference between the environmental water and the calibration chamber is minimized a
193. ible because of technical improvements to in situ water quality sensors and improved telecommunications Continuous turbidity measurement has now become a more common field approach because it provides significantly more detailed and more accurate information on suspended sediment concentrations and loadings than was previously possible Christensen and others 2000 Christensen 2001 Objectives This project will address the following objectives a Evaluate the use of continuous turbidity sensors as a surrogate for predicting suspended sediment concentrations and calculating suspended sediment loads b Compare turbidity derived suspended sediment loadings to loadings generated through classical approaches that rely on a relationship between flow and sediment the ESTIMATOR model for example c Evaluate which approach provides the most detailed and accurate suspended sediment data that can be incorporated into the various water quality models of the Chesapeake Bay Watershed d Determine whether the turbidity sediment surrogate approach is sufficiently robust over time that it results in reduced water quality monitoring costs Project Organization and Responsibility Table 1 Project organization and responsibility Personnel and Affiliation Position Responsibility Contact Doug Moyer USGS Hydrologist Project Manager 804 261 2634 Data analysis diImoyerQ usgs gov Sample Collection Ken Hyer US
194. ide both 0 to 1 000 Chapter A6 Field Measurements TBY 7 Turbidity Version 2 1 9 2005 8 TBY BACKSCATTER 90 DETECTOR DETECTOR Required Optional Optional Monitor Detector Detector angle to incident light Light Source TRANSMITTED LED Laser Diode Sample Cell DETECTOR or Tungsten Optional Figure 6 7 1 Photoelectric nephelometer single beam design showing optional additional detectors for ratiometric backscatter or transmitted determination of turbidity Modified from Sadar 1998 One outcome of the availability of different instrument designs is that turbidity measured using instruments with different optical designs can differ by factors of two or more for the same environmental sample even with identically calibrated instruments Thus raw data from differently designed instruments should not be considered directly interchangeable the resultant data are inherently incomparable without additional work to establish relations between instruments over the range of the environmental conditions present Such complications underscore the need to clearly determine study objectives before selecting a turbidimeter and to understand the limitations of the instrument selected In addition a carefully planned quality assurance QA protocol is required to identify errors associated with different aspects of the turbidity m
195. ield measurements depends on the accuracy of temperature measurements Thermistors that are incorpo rated into instruments designed to measure for example spe cific electrical conductance dissolved oxygen and pH commonly provide automatic temperature compensation Calibrate To check adjust or systematically standardize the graduations of a quantitative measuring instrument American Heritage Dictionary 1976 Chapter A6 Field Measurements Temperature Version 2 3 2006 8 T All thermometers must be tagged with their most recent date and source of certification NIST certified or trace able source for calibration thermometers and office labora tory source for field thermometers Alog book is required in which the calibration and certification history of each calibration and field thermometer is recorded TECHNICAL NOTE The accuracy of a thermometer may vary over time depending on factors such as the quality of its manufacture the frequency of its use and the conditions to which it is exposed Shock contamination rapid heating and cooling and mechanical stress are some factors that can affect the stability of a liquid in glass or thermistor thermometer ICL Calibration Laboratories 2003 2005 ASTM International 2005 6 1 2 CALIBRATION THERMOMETERS Calibration thermometers table 6 1 1 can be either a liquid in glass mercury or spirit or thermistor digital type thermometer but mus
196. ield site obtain about 1 liter L of water from the water body to be measured e If working in the laboratory obtain about 1 L of deionized water or tap water 2 Place the DO sensor and calibration water in a large beaker or open mouth container Some manufacturers supply an air satu rated water calibration vessel e Allow the sensor to come to thermal equilibrium with the water temperature e Shield the beaker or container from direct sunlight and wind to minimize temperature variations 3 Aerate the water for 5 to 10 minutes Using a battery operated aquarium pump or minnow bucket aerator and a short piece of tub ing attach a gas diffusion stone to the end of the tubing and place it at the bottom of the beaker of calibration water Avoid placing the instrument in the stream of air bubbles 4 Determine if the water is 100 percent saturated with oxygen e Observe the instrument reading while aerating the calibration water e When no change in the DO reading is observed on the instru ment for 4 to 5 minutes assume that the water is saturated 5 Using your pocket altimeter barometer read the ambient atmo spheric pressure to the nearest 1 mm of mercury 6 Read the temperature of the calibration water to the nearest 0 19C 7 Using oxygen solubility table 6 2 6 determine the DO saturation value at the measured temperature and atmospheric pressure of the calibration water Refer to section 6 2 5 and table 6 2
197. ific Electrical Conductance Version 1 2 8 2005 6 3 1 8 EQUIPMENT MAINTENANCE Maintenance of conductivity equipment includes periodic office checks of instrument operation To keep equipment in good operating condition Protect the conductivity system from dust and excessive heat and cold Keep all cable connectors dry and free of dirt Protect connector ends in a clean plastic bag Sensor cleaning and storage Conductivity sensors must be clean to produce accurate results resi dues from previous samples can coat surfaces of sensors and cause erroneous readings Refer to the manufacturer s instructions regarding long and short term storage of the sensor Clean sensors thoroughly with deionized water DIW before and after making a measurement this is sufficient cleaning in most cases Remove oily residue or other chemical residues salts with a detergent solution Sensors can soak in detergent solution for many hours without damage If oil or other residues persist dip the sensor in a dilute hydrochloric acid solution Never leave the sensor in contact with acid solution for more than a few minutes Check the manufacturer s recommendations before using acid solutions Clean carbon and stainless steel sensors with a soft brush Never use a brush on platinum coated sensors Sensors may be temporarily stored in deionized water between measurements and when the system is in daily use For long term storage
198. ight scatter yd glass Positive Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 Table 6 7 3 Summary of instrument designs and capabilities current reproducible technologies appropriate applications and approximate limits Indicated ranges are for example only and do not exclude the possibility that manufacturers can develop instruments under each design that surpass these ranges Abbreviations EPA 180 1 U S Environmental Protection Agency 1993 method 180 1 Regulatory range complies with EPA regulations unless specified non US IR infrared ISO 7027 International Organization for Standardization 1999 method 7027 nm nanometers US United States Typical instru Suggested application reference and active signals with at least four independent measurements being made The final signal is determined with a ratio algorithm Design Prominent feature and application ment capability range nm range nm Nephelometric White light turbidimeters Complies 0 to 40 40 Regulatory non ratiometric with EPA 180 1 for low level monitoring Ratiometric Complies with EPA 180 1 for low level 0 to 4 000 0 to 40 Regulatory white light monitoring Uses a nephelometric 0 to 4 000 turbidimeters detector as the primary detector but contains other detectors to minimize effects of color and noise Can be used for both low and high level
199. ily damaged than others check manufacturer s recommendations before proceeding with cleaning and use deployed dynamic monitoring the cleaning frequency should be approximately every 2 to 4 weeks More frequent cleaning is necessary where biofouling is particularly apparent Verification that wipers are operational Change wiper pads when they are excessively dirty or worn avoid hindering or forcing wiper movement or scratching optical surfaces Washing sample cuvettes after each use wear powderless disposable laboratory gloves and use a lint free cloth Regular calibration or verification against secondary calibration solutions Examination of collected data for indication of instrument malfunction gt Test all field instruments in an office or laboratory before use Record all maintenance and repairs in the instrument logbook Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 21 CALIBRATION 6 7 2 To ensure the collection of reliable turbidity data carefully follow the standard calibration procedures described below and the instructions from the instrument manufacturer Even identically calibrated turbidimeters can produce significantly different readings of native water sources for instruments of different designs turbidity instruments are designed to produce equivalent responses to scratch formazin prepared in the office laboratory the accepted r
200. ily from a field measurement Salinity correction factors based on chloride can be calculated using information provided in U S Geological Survey Quality of Water Branch Technical Memorandum 79 10 1979 Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 34 DO gt DO instruments use either an automatic internal salinity correction a manual salinity control knob for internal correction or the calibration control knob for manual salinity correction gt Check that instruments with automatic internal salinity correction use approved salinity correction factors Example of salinity correction 6 2 mg L x 0 951 7 8 mg L where 8 2 mg L is 100 percent DO saturation from table 6 2 6 0 951 is the correction factor from table 6 2 7 and 7 8 mg L is the corrected value For this example you would adjust the DO instrument to 7 8 mg L from 8 2 mg L To express results as percent saturation use the following equation measured DO mg L MM M x 100 DO mg L at 100 percent saturation DO percent saturation Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 90 35 776 7 6 476 976 976 176 876 876 676 90 07 0 0 Z OT S OT 9 0T 9 OI S vI 8 6 476 976 L 6 L 6 8 6 6 6 6 6 SOL 9 OL 90 0 vI 9 6 9 6 L 6 8 6 8 6 6 6 00 Z OT 40 SOT 902
201. in still water or from the bank unless these conditions represent most of the reach or are required by the study objectives gt Apply a salinity correction to the saturation values after the DO measurement if needed http water usgs gov software dotables html accessed Aug 26 2005 Dissolved oxygen must be measured in situ Never measure DO in subsamples from a sample splitter Follow the 7 steps below to measure DO in surface water 1 Calibrate the DO instrument at the field site and check that the temperature thermistor has been certified by the USGS Water Sci ence Center within the past 4 months NFM 6 1 2 2 Record the DO variation from the cross sectional profile and select the sampling method NFM 6 0 e Flowing shallow stream Wade to the location s where DO is to be measured e Stream too deep or swift to wade Lower a weighted DO sensor with a calibrated temperature sensor from a bridge cableway or boat Do not attach the weight directly to the sen sors or sensor cables because this could damage the sensors or sensor cables e Still water conditions Measure DO at multiple depths at several points in the cross section Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 21 3 Immerse the DO and temperature sensors directly into the water body and allow the sensors to equilibrate to the water temperature no less than 60 seconds Notes for amperometric
202. ing at the North Anna and Chickahominy Rivers as well as monthly monitoring at the James at Richmond at the Boulevard Bridge River this monthly monitoring was previously done by DEQ In 2010 the USGS began monthly and storm monitoring at Smith Creek In 2011 the Rivanna River was added to the storm monitoring network DEQ continues to collect the monthly scheduled sample at the Rivanna River site A parallel program has been conducted on 4 tributaries in Maryland by the USGS in cooperation with the Maryland Department of the Environment since 1982 A seven parameter log linear regression model Cohn 1989 which includes variables for discharge seasonality and time is used to provide estimates of constituent concentration on days when no concentration data are available The product of estimated concentrations and daily mean discharge provides daily load estimates which are then summed to provide monthly and annual loads of selected nutrients and suspended solids To evaluate long term change in the input of these constituents flow adjusted trends in concentration are computed from the regression model Langland and Others 1999 B Objectives and Scope The Chesapeake Bay River Input Monitoring Program is being used to define the magnitude timing and possible sources of nutrient inputs to the Chesapeake Bay from the non tidal areas of the larger tributaries in Virginia This sampling program provides a data base of selected constituents
203. ing protocol please refer to the Virginia CBP Non Tidal Network Quality Assurance Quality Control Project Plan for the Time Period of July 01 2010 June 30 2011 23 IV SAMPLING PROCEDURES Water quality samples are collected according to established U S Geological Survey sampling protocol for nutrients and suspended solids These methods are documented in the publications Field methods for measurement of fluvial sediment by T K Edwards and D G Glysson 1988 U S Geological Survey Open File Report 86 531 in Methods for collection and processing of surface water and bed material samples for physical and chemical analyses by J R Ward and Albert Harr 1990 U S Geological Survey Open File Report 90 140 and in U S Geological Survey protocol for the collection and processing of surface water samples for the subsequent determination of inorganic constituents in filtered water by A J Horowitz and others 1994 U S Geological Survey Open File Report 94 539 More recently all USGS field protocols have been summarized in a National Field Manual that is available online at http water usgs gov owq FieldManual index html Samples are collected in a manner ensuring that they are representative of river conditions which involves collecting horizontally and vertically integrated samples Sampling equipment is made from non contaminating materials which includes epoxy coated depth integrated samplers for collection of the nutrients and susp
204. instrument system in the data base if possible and always report it with published values Enter field determined conductivity measurements on the NWQL Analytical Services Request form using the correct parameter code Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 22 SC SELECTED REFERENCES American Public Health Association American Water Works Association and Water Environment Federation 2001 Standard methods for the examination of water and wastewater 20th ed Washington D C American Public Health Association p 2 43 to 2 48 American Society for Testing and Materials 1977 Standard test methods for electrical conductivity and resistivity of water No D 1125 77 Philadelphia American Society for Testing and Materials p 138 146 Brown Eugene Skougstad M W and Fishman M J 1970 Methods for collection and analysis of water samples for dissolved minerals and gases U S Geological Survey Techniques of Water Resources Investigations book 5 chap A1 p 148 150 Fishman M J and Friedman L C eds 1989 Methods for determination of inorganic substances in water and fluvial sediments U S Geological Survey Techniques of Water Resources Investigations book 5 chap A1 p 461 463 Hem J D 1982 Conductance a collective measure of dissolved ions in Minear R A and Keith L H eds Water analysis v 1 inorganic species pt 1 New York Academic Pres
205. intaining the Virginia data base and transferring and checking all data from VDCLS to the USGS Responsible for facilitating the transfer collation and retrieval of the data Responsible for quarterly progress reports to VDEQ DATA INTERPRETATION Hydrologist s U S Geological Survey Richmond VA Hydrologist U S Geological Survey Baltimore MD Responsible for graphing presentation and interpretation of the data application of quality assurance data and all formal report requirements for the program 19 III OBJECTIVES AND CRITERIA Because data collected for the Virginia River Input Monitoring Program are used to 1 help define the magnitude and timing of nutrient inputs to the Chesapeake Bay at the Fall Line and 2 to provide a data base of selected constituents collected during periods of varying flow and season several general quality assurance objectives are necessary in order for the program to be successful For Laboratory precision and accuracy the Virginia Division of Consolidated Laboratories DCLS replicated approximately 10 of the samples and 5 of the samples analyzed are spiked samples Detailed descriptions of the quality assurance practices for each of the analytical procedures conducted by DCLS can be found in the following SOPs Method 2506 Determination of Carbon and Nitrogen in Particulates of Estuarine Coastal Water Using Elemental Analysis Commonwealth of Virginia Department of General Services
206. issolved Oxygen rere esee een ee ee oe tete e arae eee ean DO 3 6 2 1 Amperometric and luminescent sensor methods 5 6 2 1 4 Equipment and supplies 224 6 6 2 1 B Calibration 0 eese ettet eene 10 One point and two point calibrations 10 Correction for atmospheric pressure and salinity 11 Calibration procedures eee ee eee ee eee 13 1 Air calibration chamber in air 13 2 Calibration with air saturated water 15 3 Air calibration chamber in water 17 6 2 1 C 94 19 Surface Water 19 Ground Water Lecce 22 6 2 1 D Troubleshooting amperometric instruments 24 6 2 2 Spectrophotometric 1 1 25 6 2 2 Equipment and supplies 25 6 2 2 B Calibration and interferences 26 6 2 2 C Measurement 27 Chapter 6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 2 DO 6 2 3 Iodometric Winkler method 0222 29 6 2 3 A Equipment and supplies 30 6 2 3 B Measurement eeeee eese eee
207. ith a 1 point calibration at 100 percent saturation For these instruments a zero DO check should be performed routinely as an evaluation of sensor performance see section 6 2 1 A Before each field trip Because the sensors on DO instruments may be slow to respond after the zero check the sen sor should be thoroughly rinsed with deionized water before use Some instruments allow for 2 point calibrations at 0 and 100 percent saturation Follow the manufacturer s instructions for those instruments with 2 point calibration functionality Verifying instru ment performance at zero DO and using a 2 point calibration can be particularly important for data accuracy when the instrument will be used to measure low DO concentrations less than 5 mg L Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 11 Correction for atmospheric pressure and salinity Atmospheric pressure the temperature of the water or water vapor and the conductivity or salinity of the water must be known to determine the theoretical amount of oxygen that can be dissolved in water Record all calibration information in instrument log books and copy cali bration data onto field forms at the time of calibration Ambient atmospheric pressure is true atmospheric pressure at the measurement site not that which has been adjusted to sea level Atmospheric pressure reported by the National Weather Service gener ally is not the
208. ixture and allow at least 2 minutes for the thermometer readings to stabilize 5 After the readings stabilize compare the temperature of one field thermometer at a time with that of the calibration thermometer Without removing the temperature sensor s from the test bath read the field thermometer s to the nearest graduation 0 1 or 0 5 C and the calibration thermometer to the nearest 0 1 a Take three readings for each thermometer within a 5 minute span b Calculate the mean of the three temperature readings for each thermometer and compare its mean value with the calibration thermometer c Ifthe field liquid filled thermometer is found to be within 1 percent of full scale or 0 5 of the calibration thermometer whichever is less set it aside for calibration checks at higher temperatures d Ifthe field thermistor is found to be within 0 2 of the cali bration thermometer set it aside for calibration checks at higher temperatures Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 13 B For the room temperature calibration 25 C 1 Place a Dewar flask or container filled with about 1 gallon of water in a box filled with packing insulation partially filled insulated ice chest can be used for multiparameter instruments Place the calibration container in an area of the room where the temperature is fairly constant away from drafts vents windows and harsh lights 2
209. k REDLINE RANGE THERMISTER Check Y Zero DO Check Y Solution Date WATER BAROMETRIC DO TABLE SALINITY DO DO Zero Meter Reading mg lL Adj to mg L CORR BEFORE AFTER FACTOR Membrane Changed N Y Date Time Barometer Calibrated N Y Date Time FIELD READING 1 MEDIAN mg L __ __ __ STN NO ALKALINITY ANC CALCULATIONS BEGINNING H20 TEMP C CALCULATIONS ALKALINITY ANC 1000 B Ce CF Vs PH APH VOL ACID AVOL ACID APH DC mL DC mL AVOL AGB ALKALINITY mg L As 50044 B Ca CF Vs where B volume of acid titrant added from the initial pH to the bicarbonate equivalence point near pH 4 5 in milliliters To convert from digital counts to milliliters divide by 800 1 00 mL 800 counts Ca concentration of acid titrant in milliequivalents per milliliter same as equivalents per liter or CF correction factor obtain from OWQRL for Hach acid cartridges of certain lot numbers default value is 1 00 V volume of sample in milliliters For samples with pH x 9 2 BICARBONATE meq L 1000 2 Ca CF Vs BICARBONATE mg L 61017 B 2A Ca CF Vs CARBONATE meq L 2000 A Ca CF Vs CARBONATE mg L 60009 A CF Vs where A volume of acid titrant added from the initial pH to the carbonate equivalence point near pH 8 3 in milliliters
210. l SITE SAMPLE SPECIAL PROJECT INFORMATION Optional sion ME oe s zi Sample set State County Geologic Analysis Analysis Hydrologic Hydrologic Chain of Unit Code Status Source Condition Event Custody NWQL Proposal Number NWOL Contact Name NWQL Contact Email Program Project Station Name Mattaponi River near Beulahville VA Field ID Comments to NWQL Lab split with VDCLS Hazard please explain ANALYTICAL WORK REQUESTS SCHEDULES AND LAB CODES CIRCLE A add D delete SCHED 1 1161 SCHED 2 1167 3 SCHED 4 SCHED 5 SCHED 6 Lab Code A D Lab Code A D Lab Code A D Lab Code A D Lab Code D Lab Code A D Lab Code A D Lab Code A D Lab Code A D Lab Code D Lab Code A D Lab Code A D Lab Code A D Lab Code A D Lab Code D SHIPPING INFORMATION Please fill in number of containers sent ALF COD FA FCN IQE IRM RA RU SUR TPCN BGC CRB FAM 1 FU IQL MBAS RAM RUR 1 5050 UAS C18 CU FAR FUS IOM OAG RAR RURCT TBI 1 WCA CC CUR FCA GCC IRE PHE RCB RURCV TBY CHY DOC 1 FCC GCV IRL PIC RCN RUS TOC NWQL Login Comments Collected by Phone No Date Shipped FIELD VALUES Lab P Code Value Remark Lab P Code Value Remark Lab P Code Value Remark 21 00095 51 00400 2 39086 Specific Conductance pH Standard Units Alkalinity IT mg L as uS cm 25 deg C CaCO3 99105 30 split Field Comments
211. lan for the analysis of fluvial sediment by northeastern region Kentucky district sediment laboratory U S Geological Survey Open File Report 98 384 19 p Ward J R and Harr Albert 1990 Methods for collection and processing of surface water and bed material samples for physical and chemical analyses U S Geological Survey Open File Report 90 140 71 p White K E and Sloto R A 1990 Base flow frequency characteristics of selected Pennsylvania streams U S Geological Survey Water Resources Investigation Report 90 4160 67 p APPENDIX 1 EXAMPLE OF FIELD DATA RECORD Water Quality Sampling Schedule for Station 01634000 NF Shenandoah River 7 1 2006 to 6 30 2007 Gage Height Sample Impacted ag Personnel FBLNK Field Blank CONREP Concurrent Replicate onr lt 0 APPENDIX 2 NATIONAL WATER QUALITY LABORATORY ANALYTICAL REQUEST FORM U S GEOLOGICAL SURVEY NATIONAL WATER QUALITY LABORATORY ANALYTICAL SERVICES REQUEST THIS SECTION MANDATORY FOR SAMPLE LOGIN NWIS RECORD NUMBER LAB USE ONLY V 2 4 8 2 9 X 1 SAMPLE TRACKING ID User Code Project Account NWQL LABORATORY ID 0 1 6 7 4 5 0 0 oup Ap 2 0 STATION ID Begin Date YYYYMMDD Begin Time Medium Code Sample Type 804 261 2634 dimoyer usgs gov District Contact Phone Number End Date YY YYMMDD End Time District Contact Emai
212. ld Measurements Temperature Version 2 3 2006 18 T 6 1 4 TROUBLESHOOTING Contact the instrument manufacturer if the suggestions on table 6 1 2 fail to resolve the problem or if additional information is needed When using thermistor thermometers gt Check the voltage of the batteries Start with good batteries in instruments and carry spares Table 6 1 2 Troubleshooting guide for temperature measurement Symptom Possible cause and corrective action Liquid in glass thermometer does not read accurately Check thermometer to see that the liquid is not separated if separated take back to the office laboratory to reunite column or for disposal Thermistor thermometer does not read accurately Dirty sensor remove dirt and oil film Weak batteries replace with new batteries Erratic thermistor thermometer readings Bad or dirty connection at meter or sensor tighten or clean connections Break the cables teplace cables Weak batteries replace with new batteries Thermistor thermometer slow to stabilize Dirty sensor clean sensor to remove dirt and oily film Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 19 6 15 REPORTING USGS temperature measurements should be stored in the National Water Information System NWIS data base These data may be pub lished electronically and or on paper as the verified neg
213. ler Chapter A6 Field Measurements pH Version 2 0 10 2008 26 pH Referring to figure 6 4 2 ground water is pumped directly from the well through tubing and into an airtight flowthrough cell chamber containing either a calibrated pH electrode and other sensors typically dissolved oxygen specific electrical conductance and temperature sensors fig 6 4 2A or a multiparameter sonde fig 6 4 2B After successful calibration of the pH instrument system on site pH measurement of sample water may proceed either on discrete samples obtained from a bailer or on pumped ground water circulated through a flowthrough cell chamber gt Use of the bailer to obtain ground water samples is analogous to the approved use of samplers a surface water situation as described below gt Useofaflowthrough cell chamber has the advantage of concurrent monitoring of ground water field measurements in addition to pH as described below To make a pH measurement using a flowthrough cell chamber system instrumented with single parameter sensors fig 6 4 2 1 Install the chamber system as close to the well as possible and shield the chamber and tubing from direct sunlight 2 Check that the electrode fill hole is open to the atmosphere and that the reference junction is entirely submerged 3 Check for and eliminate any backpressure condition 4 Monitor pH variation during purging a Keep the flow constant and lamin
214. libration and measurement refer to section 6 4 3 for an explanation of the Nernst equation 6 4 1 B pH ELECTRODES The pH electrode is a special type of ion selective electrode ISE that is designed specifically for the measurement of hydrogen ion concentration in a dilute aqueous solution gt Diodes or triodes combination electrodes are used in most USGS field studies Combination electrodes are housed either in a glass or an epoxy body Diodes contain a pH reference electrode and pH measurement electrode Triodes contain the reference and measurement electrodes plus a thermistor In either case the basic electrode operation is the same IC Controls 20052 combination pH electrodes have a glass membrane a reference and a measurement electrode an ionic filling solution and a reference junction shown on fig 6 4 1 these are described below Wires to pH meter Filling hole The active part of the electrode is the glass Ag AgCl membrane or bulb The glass body of the reference electrode tube has thick walls whereas the bulb is made to be as thin as possible The surface of the glass bulb is protonated by both internal and external Reference electrode solution until equilibrium is achieved Both sides internal solution of the glass are charged by the adsorbed protons this charge is responsible for potential difference described by the Nernst equation and is directly proportional to the diffe
215. lines ver 1 2 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A6 section 6 0 accessed September 19 2005 at http water usgs gov owq FieldManual Chapter6 6 0 contents html Wilde F D Radtke D B Gibs Jacob and Iwatsubo R T eds September 1999 Collection of water samples U S Geological Survey Techniques of Water Resources Investigations book 9 chap A4 accessed Sept 22 2005 at http pubs water usgs gov twri9 A4 The revised version of this report was in press at the time of this writing and is intended to replace Wagner and others 2000 upon publication The revised report will be referenced as Wagner R J Boulger R W and Smith B A 2005 Revised guidelines and standard procedures for continuous water quality monitors Station operation record computation and data reporting U S Geological Survey Techniques and Methods book 9 chap B Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 TEMPERATURE 6 1 Revised by Franceska D Wilde Page TempeLratire T 3 6 1 1 Equipment and supplies 4 Maintenance cleaning and storage 5 6 1 2 Calibration eene eese eee eene 7 6 1 2 Calibration 8 6 1 2 B Field 5 9 6 1 3
216. liquot of sample onto the sensors and swirl the sample water around the electrode sensors Discard the sample appropriately b Second rinse Pour an aliquot of sample onto the sensors and allow the sensors to sit in the solution for 1 minute do not swirl Discard the sample appropriately 5 Measure pH as follows a Poura third aliquot of sample into the vessel Allow the sensors to sit in a quiescent sample for 1 minute or until the pH value stabilizes within the established criterion Record the pH value on the electronic or paper field notes form b Repeat the procedure in a above on at least two additional aliquots of the sample recording the pH measurement for each aliquot on the field form s 6 Calculate a final sample pH as the median of the values measured for the sample aliquots and document the calculation on field forms 7 Record the final pH value of the sample to the nearest 0 01 pH unit along with the sample temperature in paper and or electronic field forms including forms that accompany samples being shipped to the laboratory 8 The pH value should be reported to the nearest 0 1 pH unit when published and when recorded in the NWIS database Always record the temperature of the sample concurrently with each pH measurement Chapter A6 Field Measurements pH Version 2 0 10 2008 24 pH 6 4 4 B pH MEASUREMENT IN GROUND WATER The pH of ground water should be measured unde
217. logical Survey TWRI Book 9 T 11 Record the calibration data in the instrument log book for each thermistor thermometer including thermistor containing field meters noting if a temperature sensor has been replaced Calibrate field thermometers every 12 months To calibrate field thermometers when a commercial refrigerated water bath is available 1 Precool the sensor of the thermometer s being tested field thermometer to 0 C by immersing it in a separate ice water bath 2 Immerse the field and calibration temperature sensors in the refrigerated bath with a water temperature of approximately 0 C 3 Position the temperature sensor s so that they are properly immersed and so that the scales can be read Stir the water bath and allow at least 2 minutes for the thermometer readings to stabilize 4 Without removing the temperature sensor s from the refrigerated water bath read the field thermometer s to the nearest graduation 0 1 or 0 5 C and the calibration thermometer to the nearest 0 1 C a Take three readings within a 5 minute span for each field thermometer b Calculate the mean of the three temperature readings for each field thermometer and compare its mean value with the calibration thermometer c Ifa liquid filled field thermometer is found to be within 1 percent of full scale or 0 5 C of the calibration thermometer whichever is less set it aside for calibration checks at higher temperatur
218. lopment proceeds gt During well purging Monitor changes in turbidity by taking sequential readings until purging criteria are met NFM 6 0 The final stabilized turbidity value should be equal to or less than the value recorded at the end of well development A decrease in turbidity values during purging can indicate mitigation of subsurface disturbance caused by well installation and by deployment of data collection equipment in the well gt For dynamic measurement Report the median of the three or more sequential measurements that meet the 10 percent criterion for stability NFM 6 0 For discrete sample measurement using a turbidimeter or spectrophotometer Bailers are not recommended for collecting turbidity samples as bailer deployment can increase turbidity Do not collect the discharge passing through the flowthrough chamber in which pH conductivity or other field measurement sensors are installed 5Diluted samples must be qualified with a 4 in the Value Qualifier Code field when entering data into NWIS Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 42 TBY Pump the ground water sample directly from the sample discharge line into a precleaned glass or polyethylene sample collection bottle Subsample into a cuvette and measure turbidity according to instructions for static determination steps 3 through 5 above Multiparameter instruments can be used with
219. lowing the standard procedures outlined by Wagner and others 2000 these continuous data will be of known quality and will be able to be compared to any other continuous water quality data that also were collected following these guidelines Discrete water quality sampling protocols Discrete water quality samples will be collected from each of the three continuous monitoring stations over a wide range of flow conditions as part of the ongoing River Input Monitoring Project These discrete water quality samples will be collected following standard USGS protocols for the collection of water quality samples USGS 1998 As these standard methods are well documented in published USGS manuals only a summary is presented here Samples will be collected over a wide range of flow conditions with special effort paid to the collection of water quality samples during storm flow conditions Samples that are collected following USGS protocols will be analyzed using USGS approved methods for the analysis of those samples Suspended sediment samples will be shipped to the USGS Eastern Region Sediment Laboratory for analysis following approved sediment analysis techniques Sholar and Shreve 1998 Remaining water quality analyses will be submitted to the Virginia Division of Consolidated Laboratory Services DCLS This laboratory has been reviewed and approved by the USGS for the analyses that are performed As described in the USGS manuals for water quality sam
220. lve pH measurement and sampling of high ionic strength waters ionic strength greater than 3 M or conductivity greater than 20 000 uS cm from sources such as industrial effluent for example from paper mills oil refineries carbonate processing or other mining activities that have corrosive properties combined sewer storm water from urban systems seawater and brines Using standard buffers or standard equipment may not yield an accurate pH measurement for such waters The high ionic strength of some industrial effluents or brines often are of greater or equal ionic strength than that of the filling solution in the standard pH electrode This results in an ionic gradient toward the reference junction and into the pH electrode which compromises the design parameters of the electrode and therefore the soundness of the calibration and the pH measurement gt Standard buffers are not of an ionic strength that approximates or exceeds the ionic strength of the sample solution and standard filling solutions in pH electrodes similarly may have too low of an ionic strength to be calibrated properly for measurement of pH in high ionic strength waters When selecting the measurement system to be used to determine the pH of high ionic strength waters consider the following options 1 Obtain high ionic strength conductivity greater than 20 000 uS cm pH buffer solutions from commercial sources if available Follow the guidelines for maintenance a
221. ly and does not imply endorsement by the U S Government Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 3 DISSOLVED OXYGEN 6 2 The concentration of dissolved oxygen in water is affected by many factors including ambient temperature atmospheric pressure and ion activity Accurate data on the concentration of dissolved oxygen DO in environmental water resources are essential for documenting changes that result from natural phenomena and human activities Sources of DO in water include atmospheric aeration and photosyn thetic activities of aquatic plants Many chemical and biological reac tions in ground water and surface water depend directly or indirectly on the amount of available oxygen Dissolved oxygen is necessary in aquatic systems for the survival and growth of many aquatic organisms and is used as an indicator of the health of surface water bodies DISSOLVED OXYGEN molecular oxygen oxygen gas dissolved in water Standard field methods used by the U S Geological Survey USGS for determining concentrations of DO in surface and ground waters include the use of amperometric and luminescent based sensor instruments and spectrophotometric analysis Selection of a measurement method should take into consideration environmental conditions the specific data quality objectives of the data collection program and the inherent benefits of a given technology Except where noted these methods
222. m t c o o V wo m o 9 o 5 wo QN i p er Te N P wo o voc Sre wo m p EST 0 D m o o a n E ur a eue e er o i o pe Sc wo l m x A Ep 0 wo 4 o o m a o d E m N o o n i R o pe I wo d nn BE v un o o _ o E m 255 m m o n Sat n nn HCM 0 o o un Tm is uu i23 seg m o 2 Acc 844 n E BS o wo 3 o o o o 3 3 71 gt a m Sos M m 205 gt NN 5 IDE o o BS wo x o N o o T EEE iac n c HN gt o Al lt o 3 em o o 5 wo wo un iac ui o i em 244 o a BOR wo m o E 3 o EROR E man o i 1 4 SCC oe aware wo i o eon 3
223. manual E A Ciganovich I M Collies Davis C M Eberle Iwatsubo Palcsak Pearsall Radtke D A Sherwood Welch Wilde White Chester Zenone and the analysts of the USGS National Water Quality Laboratory Improvements to the technical quality of this revision to Section 6 2 Dissolved Oxygen can be attributed to the expertise and conscientious efforts of technical reviewers Jacob Gibs J A Kingsbury and S C Skrobialowski Special appreciation is extended to the scientists from the Hach In Situ Inc and YSI Inc companies who were generous with their time and expertise in explaining luminescent sensor technol ogy The editorial and production quality of this report is a credit to I M Collies and L J Ulibarri Thanks go to F D Wilde managing edi tor of the National Field Manual for maintaining the integrity of the technical and publication process Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 TBY 1 TURBIDITY 6 7 By Chauncey W Anderson Page Turbidity S a SWR V UR MES QUE QUEUE TBY 3 6 7 1 Equipment ereeee eene aereas ebenso 5 6 7 1 A Interferences and instrument design 5 6 7 1 B Data Storage 9 6 7 1 C Instrument selection and maintenance 11 Decision considerations for instrument selection 444
224. mark with turbidity free water and mix 3 Transfer the solution to an opaque light blocking polyethylene bottle Prepare the calibrant suspension on the day the calibrant is needed use it immediately after preparation and discard unused calibrant The 40 turbidity unit stock solution is stable only for about 1 day When chemicals to be used for preparation of reagents are received mark the dates of receipt and expiration on the container When a calibrant is prepared label the container with the contents date of preparation expiration date and preparer s initials Store formazin in a cool dark place a storage cabinet or frost free refrigerator After use pour waste calibration solutions into a labeled glass or plastic container for proper disposal Reagents and calibrants must not exceed their shelf life 6 7 2 B CALIBRATION PROCEDURES Although calibration principles are similar whether using static or dynamic sensors in practice the steps taken can be different Benchtop meters use a small 15 to 25 mL sample holding cell or cuvette which is inserted into the measurement chamber This results in a static measurement unless additional flowthrough equipment is used Values must be read from the meter before particle settling can affect the measured turbidity If particle settling of sand or silt occurs before the measurement can be completed the sample results must be recorded in the database to re
225. measurement Nephelometric Complies with ISO 7027 The 0 to 1 000 11 Regulatory near IR wavelength 780 900 nm is less non US turbidimeters susceptible to effects of color Good 0 to 1 000 non ratiometric for samples with color and good for low level monitoring Nephelometric Complies with ISO 7027 Contains a 0 to 4 000 0 to 40 Regulatory near IR ratio algorithm to monitor and 0 to 4 000 turbidimeters compensate for variability and color ratiometric Surface scatter Not applicable for regulatory purposes 10 to 10 000 10 to 10 000 turbidimeters Turbidity is determined through light scatter from or near the surface of a sample The detection angle is still nephelometric but interferences are not as substantial as nephelometric non ratiometric measurements This is primarily used in high level turbidity applications Backscatter Not applicable for regulatory purposes 10 to 10 000 10 to 10 000 ratiometric Backscatter detection for high levels technology and nephelometric detection for low levels Backscatter is common with probe technology and is best applied in high turbidity samples Light attenuation Not applicable for regulatory purposes 20 to 1 000 20 to 1 000 spectro Wavelength 860 nm Highly photometric susceptible to interferences best applied at low to medium turbidity levels Multiple beam Multiple light sources and multiple 0 to 40 40 Regulatory turbidimeters detectors are used to prov
226. method assumes the turbidimeter recently has been calibrated properly with a calibration or verification solution section 6 7 2 Benchtop determination of turbidity is especially susceptible to negative bias from particle settling Visually check for the presence of coarse material sand or coarse silt in the sample Gently agitate the sample then set it down If particles rapidly settle to the bottom within 3 5 seconds then coarse materials are present and the sample cannot be measured accurately using the static method Static measurements made on such samples therefore must be coded to indicate that accuracy is qualified when being entered into a database In the USGS NWIS database for example the results should be entered with an remark code Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 35 Preliminary steps for benchtop turbidity determination 1 Warm up the turbidimeter according to the manufacturer s instructions Put on powderless laboratory gloves Rinse a clean dry scratch free index marked cell with a turbidity calibrant within the range of interest Gently agitate the calibrant pour the calibrant into the sample cell to the fill mark and dry the cell exterior with a lint free cloth When using a meter recently calibrated with an acceptable calibrant turbidity solution formazin or styrene divinylbenzene polymer see section 6 7 2 a verification calibrant may be us
227. mple simulates dynamic measurement using a flowthrough chamber with its benchtop meters If a dynamic measurement is used for determining field turbidities it can be useful to compare these data with results obtained from a laboratory analyzed sample as long as the properties contributing to the sample turbidity do not degrade during storage and transit see section 6 7 3 Dynamic measurement is the preferred method for determining the turbidity of a water body provided that this method is consistent with study objectives and other study protocols Dynamic measurement more accurately reflects surface water conditions than static determination because particle settling in cuvettes is avoided Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 18 TBY Signal Processing Options Because turbidity measurements can be highly variable a range of signal processing options may be available with different instruments Some instruments can provide statistics such as the maximum minimum mean median range and variance of many readings over a timespan of a few seconds These statistics can be useful for reducing variability in recorded turbidities for understanding sources of turbidity or for diagnostic purposes Instruments that use proprietary algorithms can provide functions intended to reduce spikes in instantaneous data sometimes employing user defined variables such as time constants and spike thresholds Such al
228. n and the sample being measured This junction is necessary for the proper functioning of the pH sensing electrical cell it must allow free movement of electrons but at the same time isolate the ionic solution from the bulk environmental sample Typically this junction is made of a porous material such as ceramic Teflon or glass fiber and may clog and malfunction if not maintained properly The function of the reference junction is characterized by a chemical memory In a correctly functioning pH electrode a small amount of time lapses before the appropriate ionic bridge is formed between the electrode reference ionic solution and the external environmental sample or external calibration buffer solution The length of time necessary for the establishment of this ionic equilibrium is a primary reason for the requirement that pH be measured in a quiescent sample solution Sections 6 4 4 and 6 4 5 provide further discussion Remember to check that the junction on the pH electrode is not clogged a clogged electrode will not function properly Electrode performance naturally deteriorates over time under normal operating conditions However use of the electrode in severe chemical environments can cause more rapid deterioration table 6 4 2 Many of these environments are coincident with industrial and urban locations immersing a pH electrode in such environments should be avoided or minimized to the extent possible IC Controls 2005a W
229. n suspended sediment and stream discharge With the current limitations for predicting suspended sediment levels innovative approaches for generating detailed records of suspended sediment concentrations are needed One promising new technology for improved suspended sediment determination involves the continuous monitoring of turbidity as a surrogate for suspended sediment concentrations Turbidity measurements are well correlated to suspended sediment concentrations because turbidity represents an optical measure of water clarity and it is the presence of suspended sediments that directly influences this measurement of clarity Using turbidity values as a surrogate for calculating suspended sediment concentrations is not new but until recently technological limitations have made this approach largely unreasonable As early as 1977 Walling described this surrogate approach using turbidity and demonstrated a sharp reduction in suspended sediment prediction error using a turbidity sediment relationship relative to a discharge sediment approach In the earlier mentioned study by Christensen and others 2002 that demonstrated poor correlation between suspended sediment concentrations and discharge 100 of their research stations demonstrated significant correlations between suspended sediment concentrations and turbidity measurements The development of continuous turbidity records to calculate suspended sediment concentrations is now inherently more feas
230. nal Institute of Standards and Technology NIST or is manufac turer certified as NIST traceable Calibration should be performed in a laboratory environment every 6 to 12 months depending on the manu facturer s recommendation Field thermometers Only calibration thermometers having current NIST certification or traceability can be used for checking the accuracy of calibrating field thermometers the case of continuous monitors a nonmercury calibra tion thermometer can be used in the field to check or monitor temperature readings whenever other field measurement sen sors are calibrated See Wagner and others 2006 for spe cific guidelines for continuous monitors Calibration thermometers are calibrated during their manufacture and certified as NIST certified or NIST traceable at the manufacturing laboratory The USGS requires that calibration thermometers be recertified by a professional calibration service at least every 2 years or be replaced with a calibration thermometer having current certification Calibration thermometers should be reserved for calibration and should not be used routinely as field thermometers see TECHNICAL NOTE Mercury filled thermometers must never be used outside of the laboratory thermistors included in other field measurement instru ments must be calibrated checked routinely as specified below for thermistor thermometers since accurate determi nation of other f
231. nd again while at the field site 6 4 2 ELECTRODE CARE AND CLEANING USGS field personnel should integrate the following guidance for the care and cleaning of pH electrodes into their routine field measurement procedures P Never handle the glass bulb with fingers Oily film or scratches on the bulb will interfere with the design characteristics of the glass membrane and affect subsequent pH measurements P Inspect the electrode and electrode cable for physical damage For example check for or frayed cable s Broken connectors and mismatched or missing parts A visibly scratched or broken bulb cracked electrode body and broken or damaged internal electrode reference and measurement electrodes P Gel filled electrodes do not require filling and typically require less maintenance than liquid filled electrodes Do not store gel filled electrodes in dilute water even temporarily as salts may leach from the gel into the dilute water and produce a large junction potential resulting in errors in pH measurement pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 11 To prepare and care for liquid filled electrodes 1 Remove salt crystal deposits from the electrode membranes and junctions by rinsing with deionized water DIW Visually check that the reference junction is not blocked or caked with salt Thorough rinsing with DIW should remove these deposits Be sure to unplug the fill hole
232. nd use of pH buffers previously described in section 6 4 1 C paying close attention to the effect of temperature on buffer values 2 Obtain high ionic strength pH glass electrodes if available These may be characterized by filling solutions of greater than 3 M ionic strength and more solution specific glass sensors Note specific uses recommended by the manufacturer and follow the manufacturer s instructions 3 If no suitable pH glass electrode buffer system is available for pH measurement in high ionic strength environments investigate the suitability of alternative instrumentation and methods such as those that employ spectrophotometric or optical methods with respect to the site specific conditions to be encountered and study data quality objectives Bellerby and others 1995 Farquharson and others 1992 Sedjil and Lu 1998 Spectrophotometric methods typically involve the constant rate introduction of acid base indicator dyes into the sample pH measurement is accomplished by measurement of the resultant spectra of the dye An important limitation to this system is that acid base indica tor dyes are typically sensitive over very narrow pH ranges Raghuraman and others 2006 Spectrophotometric measurement of pH in environmental samples is a methodology designed for specific environments follow the guidelines provided by the equipment manu facturer As part of USGS studies any pH data obtained by spectrophotometry or other
233. ng on the x axis and read the corresponding corrected turbidity value from the y axis or determine the corrected y value from the regression equation on the instrument reading 7 Adjust the calibration control until the value on the meter equals the value of the calibrant used 8 Repeat steps 4 through 7 as recommended by the instrument manufacturer for calibration solutions bracketing the range of expected turbidities Use calibrants representing at least two different turbidities including the expected maximum and minimum Ensure that calibrants are within the linear portion of the instrument s operating range Submersible dynamic turbidity sensor calibration Most dynamic turbidimeters and multiparameter instruments with turbidity sensors are microprocessor based with the calibration parameters stored in instrument memory Turbidity values of the calibrants are user selectable in some instruments but others have internally established calibration ranges that cannot be changed gt Check calibrants in the 1 to 5 turbidity unit low level range to assess the actual performance of the instrument near the detection limit instrument reliability often decreases at turbidities less than 2 turbidity units consult the manufacturer s specification for the expected accuracy of the measurement Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 30 TBY gt Refer to Wagner and others 2000 for instructions on reco
234. ngle must be 90 30 to the incident light beam The light source must be a tungsten lamp with color temperature 2 200 3 000 K Source U S Environmental Protection Agency 1993 2150 7027 defines the optical geometry for FNU measurements The detector angle must be 90 2 5 to the incident light beam The light source must be a light emitting diode LED with wavelength 860 60 nm Source International Organization for Standardiza tion 1999 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 11 INSTRUMENT SELECTION AND 6 7 1 C MAINTENANCE Owing to potential differences in turbidity readings resulting from different instrument types it is critical that when selecting turbidimeters investigators carefully consider the objectives of the study and the uses of the resulting data Considerations include Whether the program will be regulatory in nature typically applies in a drinking water context gt The expected range in turbidity and the portions of that range that will be the most important to measure with accuracy gt The need for consistency of method and comparability among data sources whether data from one site need to be comparable with data from another site or with historical data Which potential interferences are the most important to quantify or otherwise take into account tables 6 7 1 through 6 7 4 Within the United States turbidity is regulated
235. nit it is not unusual to measure turbidities of 1 000 or greater depending on stream and weather conditions Uhrich and Bragg 2003 Protocols for determining turbidities in surface waters typically must account for making reliable measurements that span turbidities over one to three orders of magnitude Use either a dynamic or static method employing either discharge weighted pumped sample or grab sample procedures as appropriate for site characteristics and study objectives NFM 6 0 Repeat the measurement three to five times to ensure accuracy and replication within the precision of the instrument 6 7 3 A STATIC BENCHTOP DETERMINATION The methods described below encompass both white light nephelometry that meets USEPA specifications for drinking water and other static methods for example ISO 7027 that do not meet USEPA specifications EPA Method 180 1 is applicable in the range of turbidity from 0 to 40 NTU without dilution and from about 40 to 1 000 NTU with dilution U S Environmental Protection Agency 1993 Note that dilution of environmental samples that contain particulate materials or exhibit other nonlinearity properties can introduce significant errors from subsampling therefore dilution is discouraged Reporting units will vary with the instrument type used Consult table 6 7 3 and the turbidity parameter and methods codes spreadsheet http water usgs gov owq turbidity codes xls accessed 9 30 2005 The static
236. nsferred Copy the temperature correction information onto the respective buffer container or keep a copy of this information with the buffers being transported to the field gt Discard the pH buffer on its expiration date The pH of a buffer can be altered substantially because of temperature fluctuation carbon dioxide CO absorption mold growth or evaporation Use the following precautions and protocols to help ensure the accuracy of the pH measurement modified from Busenberg and Plummer 1987 Cap buffer bottles firmly after use to prevent evaporation and contamination from atmospheric The pH 10 buffer has the greatest sensitivity to contamination whereas the pH 4 buffer is the least sensitive Buffers are stable for the short exposure time during electrode calibration Never pour used buffer back into a bottle containing the stock buffer solution Do not insert an electrode or other material into a bottle containing stock buffer solution always pour the buffer into a separate container and discard the solution after use Take care not to contaminate the buffer with another buffer or with other fluids Do not let the buffer become diluted this can happen for example if deionized water used to clean the electrode drips into the buffer Protect buffers against wide temperature variations whether in transit during use or in storage Never expose buffers to extreme heat or freezing temperatures If
237. ntal sample in the diluted mixture EXAMPLE If five volumes of turbidity free water were added to one volume of sample and the diluted sample showed a turbidity of 30 units then the turbidity of the original sample is computed as 180 units Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 41 e Report turbidity as follows using method codes as described in http water usgs gov owq turbidity codes xls accessed 9 30 2005 For EPA Method 180 1 use NTU or NTRU For GLI Method 2 use FNMU For non diluted non USEPA compliant measurements use the reporting units described in table 6 7 4 In contrast to surface waters natural turbidity in ground water generally is less than 5 turbidity units Natural ground water turbidity of up to 19 turbidity units has been reported for some environmental settings Nightingale and Bianchi 1977 Strausberg 1983 Puls and Powell 1992 Contaminated ground water systems however can have considerably higher turbidity Wells and others 1989 Gschwend and others 1990 Puls and Powell 1992 Backhus and others 1993 Measuring turbidity in ground water requires special considerations and procedures For effervescent ground water a degassing apparatus may be required follow manufacturer s instructions gt During well development Monitor turbidity caused by well installation recording consecutive measurements to document decreases in turbidity as deve
238. ntration and discharge and concentration and seasonality at each river The load estimates will be compared to the loads from other rivers in the Chesapeake Bay in order to see the relative differences between the basins Differences may be examined using land use information discharge records and possibly point and nonpoint sources of constituents Trend estimates will be used to determine the changes in constituent inputs over the period of study and to assess the impact of management practices implemented during that time Historical data may be used as background information for comparison purposes Quality assurance data are used on an ongoing basis to evaluate field and analytical methods for representativeness variance bias and accuracy D Study Design and Rationale The contributing basins for this report together comprise about 22 percent of the total Chesapeake Bay drainage area The James and Rappahannock River basins represent approximately 13 and 4 percent of the Chesapeake Bay drainage area the Appomattox part of the lower James River Basin represents another 2 5 percent and the Pamunkey and Mattaponi River basins represent about 2 and 1 percent of the total Chesapeake Bay drainage area The remaining percentage of Virginia within the Chesapeake Bay watershed is comprised of the Potomac River basin and its tributaries including the Shenandoah River which are monitored by the USGS Virginia and Maryland Water Science Centers
239. ntrations in the range of 0 2 to 2 0 mg L and 2 0 to 15 0 mg L also can be determined spectrophotometrically using an Indigo Carmine method Gilbert and others 1982 www chemetrics com catalogpdfs html accessed May 15 2006 Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 26 DO Table 6 2 4 Equipment and supplies for the spectrophotometric method of dissolved oxygen determination mm millimeter DO dissolved oxygen concentration mg L milligrams per liter uS cm microsiemens per centimeter at 25 degrees Celsius Portable spectrophotometer capable of accepting a 13 mm diameter ampoule or CHEMetrics multianalyte photometer catalog no V 2000 or V 1000 v Vacu vial kit CHEMetrics Inc Catalog number 75531 for a DO range of 0 1 to 0 8 mg L when using a spectrophotometer or the V 1000 photometer and 0 1 to 1 4 mg L when using the V 2000 photometer Note The V 1000 is being discontinued Submersible sampling tool used in situ to meet criteria described in White and others 1990 For example Downhole sampler or Plastic sampler tube overflow cell and short length of C flex tubing Safety gloves glasses and apron v Waste disposal container v White background sheet Deionized water maximum conductivity of 1 uS cm Bottle squeeze dispenser for deionized water Photometers and visual kits are described by CHEMetrics Inc for a variety o
240. o minimize dilution or contamination of the next calibrant h Discard the calibrant into a labeled waste container and hold for proper disposal i Ifmeasurement of color derived turbidity is not desired filter using a 0 2 um pore size filter an aliquot of the sample water and use the filtered water in place of turbidity free water 5 Using a second calibrant with a value near the maximum of the expected turbidity range repeat steps 4 a i Repeat again with a third calibrant near the middle of the expected range if increased accuracy is desired and instrument software permits If the software does not permit a three point calibration the third calibrant can nonetheless be used to document the accuracy of the calibrated instrument near the middle of the expected range If an of range error is displayed verify the intended calibrant value and start again with the first zero calibrant solution Repeat the calibration procedure if the measurement is not within the specification Record all calibration and verification measurements in the instrument logbook 6 Onaone time basis determine the maximum value that can be reported by the instrument by holding a lint free cloth over the optical sensor and recording the turbidity Use this value as an indicator that turbidity might have been greater than the range of the instrument during measurements in a water body Chapter A6 Field Measurements Turbidity Version 2 1 9 2005
241. o rE QUE fet EET PET S EI 9 SET G ET OFT TPE ZFT PFT GPL 8 870 SUPE G Er Eek RE SOUPE QUEE CPE EPE OSE COSE ESE 070 004 SOL OTL STL 024 StL OEL SEL 074 SbL OSL SSL 09L SOL OLL SLL 08L 984 064 864 Do JO ur otTreydsowqy duel 9 0 Jaye 009 01 669 W044 Sainssaid snis a J 0 61 SSI M JH W014 seJnssaJd pue sainjesadwa 3e ui jo Aqyignjos 79 220 8 481 Dissolved Oxygen Version 2 1 6 2006 Chapter A6 Field Measurements 36 DO o or lt un or o i d h H c oO 4 NANNA o mr 5 NMN o 5 gt H in vo xg 0m a s o ae DH C ovo m at DNAAAD 9 m ER DH o A o MAN E o nan ii Qn c Y mm c Bg on a a an 5 a un o t
242. o remove resistant residues check manufacturer s guidelines Air trapped in conductivity sensor agitate sensor up and down to expel trapped air Weak batteries replace Temperature compensation incorrect ensure that thermometer is operating properly and is calibrated Sensor constant incorrect Treplace sensor Erratic instrument readings Loose or defective connections tighten or replace Broken cables tepair or replace Air trapped in conductivity sensor agitate sensor up and down to expel trapped air Rapid changes in water temperature measure in situ Outgassing of ground water sample use downhole instrument if unavailable use a flowthrough chamber Broken sensor replace Instrument requires frequent recalibration Temperature compensator not working measure conductivity of a solution Place solution in a water bath and raise solution temperature to about 20 Measure conductivity again allowing sufficient time for temperature of conductivity sensor to equilibrate to temperature of solution If the two values differ by 5 percent or more replace conductivity sensor Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 SC 21 REPORTING 6 3 5 Report routine conductivity measurements to three significant fig ures whole numbers only in microsiemens per centimeter at 25 gt Record the accuracy range of the
243. oard flow injection determination of sea water pH with spectrophotometric detection Analytica Chimica Acta v 309 no 1 p 259 270 Brown Eugene Skougstad M W and Fishman M J 1970 Methods for collection and analysis of water samples for dissolved minerals and gases U S Geological Survey Techniques of Water Resources Investigations book 5 chap A1 p 129 130 Busenberg Eurybiades and Plummer L N 1987 pH measurement of low conductivity waters U S Geological Survey Water Resources Investigations Report 87 4060 21 p Drever J I 1988 The geochemistry of natural waters 2d ed Englewood Cliffs N J Prentice Hall p 282 304 Farquharson Stuart Swaim P D Christenson C P McCloud Mary and Freiser Henry 1992 Fiber optic based pH measurement in a geothermal brine in Wlodarczyk M T ed Chemical Biochemical and Environmental Fiber Sensors proceedings SPIE The International Society for Optical Engineering v 1587 p 232 239 Abstract available at http adsabs harvard edu abs 1992SPIE 1587 232F Fishman M J and Friedman L C eds 1989 Methods for determination of inorganic substances in water and fluvial sediments U S Geological Survey Techniques of Water Resources Investigations book 5 chap A1 p 363 364 Gibs Jacob Wilde F D and Heckathorn H A 2007 Use of multiparameter instruments for routine field measurements ver 1 0 U S Geological Survey Techniques of Water Re
244. ode 2 Rinse a freshly cleaned cell with the sample to be tested 3 Fora discrete static sample complete the following sequence of steps through step 4a without hesitation skip to step 4 for flowthrough cell measurement a Gently invert do not shake the sample 25 times ASTM written commun undated to completely disperse the solids taking care not to entrain air bubbles Allow air bubbles to disappear before filling the sample cell b Rapidly pour the sample into a sample cell to the line marked to the neck if there is no line Do not touch cell walls with fingers c Remove condensation from the cell with a clean soft lint free cloth or tissue If condensation continues apply a thin coating of silicon oil to the outside of the cell about every third time the cell is wiped dry of moisture Allow samples to equilibrate to ambient temperature if necessary before subsampling to help minimize condensation problems Note warming the sample may change particle associations in the water matrix d Before inserting the sample cell into the meter ensure that no air bubbles are present in the cell If necessary degas the sample according to the manufacturer s instructions Air bubbles can cause significant positive bias in turbidity measurements table 6 7 1 e Orient the calibration cell in the cell holder according to the index marks the calibration cell and sample cell must have identical orientation when in t
245. ole or the flowthrough chamber system e Downhole system lower the sensor in the well to just below the pump intake the intake location depends on the sampling objectives e Flowthrough chamber system properly immerse the ther mistor or liquid in glass thermometer in the chamber Keep the pump tubing from the well to the chamber as short as possible out of direct sunlight and off the ground Keep the chamber out of direct sunlight and wind 2 Begin water withdrawal from the well Allow the thermometer to equilibrate with ground water temperature for no less than 60 sec onds or in accordance with the manufacturer s guidelines record the readings and time intervals throughout the period of purging 3 Toward the end of purging record five or more sequential mea surements spaced at increments of 3 to 5 minutes or more e Ifthe thermistor temperature is stable within the 0 2 C crite rion report the median of the final five measurements table 6 0 1 For a liquid in glass thermometer there should be only slight fluctuation around 0 5 C e Ifthe stability criterion has not been met extend the purge time and consult the well purging objectives of the study Report the median of the last five or more sequential measurements and record any instability on field forms 4 Remove the thermometer from the water rinse it thoroughly with deionized water blot it dry and store it as described in 6 1 1 Chapter A6 Fie
246. on date of the first buffer Typically the meter will initially indicate the pH 7 buffer isoelectric point 7 Begin calibration procedures a Note that the electrode and thermistor must be rinsed with DIW at least three times between uses of each buffer b Rinse the electrode twice with the first buffer usually the pH 7 buffer Do not allow the glass membrane of the electrode to come in contact with the sides or bottom of the beaker or other measurement vessel i First rinse Pour enough buffer into a small beaker or other vessel so that it covers the electrode reference junction swirl the buffer to rinse the electrode body from above the reference junction to the bottom of the bulb Discard buffer appropriately ii Second rinse Pour the next aliquot of buffer into the vessel and immerse the electrode in the buffer for 1 minute Discard buffer appropriately c Pour another aliquot of buffer into the vessel Immerse the electrode for 1 minute without swirling the buffer solution d Record the pH measurement shown on the meter display in the pH meter electrode logbook along with the buffer temperature reading and the pH value from the buffer and temperature table e For pH meters displaying millivolt values the meter will display the value associated with the pH 7 buffer as compensated for the buffer temperature For properly functioning electrodes the pH 7 millivolt value should be between 10 and 10 mV Record the
247. on factors for converting non temperature compensated values to conductivity at 25 degrees Celsius based on 1 000 microsiemens potassium chloride solution Use of potassium based constants on non potassium based waters generally does not intro duce significant errors for general purpose instruments used to measure conductivity Temperature Correction Temperature Correction Temperature Correction degrees factor degrees factor degrees factor Celsius Celsius Celsius 0 5 1 87 10 5 1 39 20 5 1 09 1 0 1 84 11 0 1 37 21 0 1 08 1 5 1 81 11 5 1 35 21 5 1 07 2 0 1 78 12 0 1 33 22 0 1 06 2 5 1 76 12 5 1 32 22 5 1 05 3 0 1 73 13 0 1 30 23 0 1 04 3 5 1 70 13 5 1 28 23 5 1 03 4 0 1 68 14 0 1 27 24 0 1 02 4 5 1 66 14 5 1 26 24 5 1 01 5 0 1 63 15 0 1 24 25 0 1 00 2 2 1 60 15 5 1 22 25 5 0 99 6 0 1 58 16 0 1 21 26 0 0 98 6 5 1 56 16 5 1 19 26 5 0 97 7 0 1 54 17 0 1 18 27 0 0 96 7 5 1 52 17 5 1 16 27 5 0 95 8 0 1 49 18 0 1 15 28 0 0 94 8 5 1 47 18 5 1 14 28 5 0 93 9 0 1 45 19 0 1 13 29 0 0 92 9 5 1 43 19 5 1 12 29 5 0 91 10 0 1 41 20 0 1 11 30 0 0 90 Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 5 11 To extend the temperature range shown in table 6 3 3 consult the manufacturer s guidelines If these are unavailable use the following equation C Cos 150021225 m where C 5 corr
248. on solutions Use consistent techniques and instrumentation throughout a data collection program lFor additional procedures related to continuous dynamic monitoring of environmental waters refer to Wagner and others 2000 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 5 EQUIPMENT 6 7 1 When selecting an appropriate instrument for measuring turbidity consider the potential effects that may result from the various properties of different water bodies In addition ensure that the measurement method instrument design and the data output are appropriate for the purpose and objectives for which these data are to be collected INTERFERENCES AND 6 7 1 INSTRUMENT DESIGN A variety of water properties can affect the measurement of turbidity table 6 7 1 These include the color of dissolved constituents in the water matrix and particulate materials particle size and density Sensor fouling such as biological growth or scratches on the optical surface of the instrument tends to produce a negative bias when light beams are blocked but can produce a positive bias if scratches increase the scatter of the sensor s light beam table 6 7 2 Likewise bubbles or gases in the water can cause apparent turbidity positive bias and might require special sample preparation or handling to eliminate without changing the particle characteristics of the original sample consult manufacturer s recommen
249. on the field form gt DO concentrations are determined to the nearest 0 1 mg L gt If the concentration exceeds 20 mg L report gt 20 mg L gt Note that the percentage of DO saturation in water can be greater than 100 CORRECTION FACTORS FOR 6 25 OXYGEN SOLUBILITY AND SALINITY Correction factors for the solubility of oxygen at various temperatures and pressures and for salinity based on conductivity are given in tables 6 2 6 and 6 2 7 respectively Tables 6 2 6 and 6 2 7 were generated from the equations of Weiss 1970 and can be customized to cover the range and decimal places needed see U S Geological Survey Quality of Water Branch Technical Memorandum 81 11 1981 Interactive software to generate a specific range of oxygen solubility and salinity correction factors be accessed at http water usgs gov software dotables html accessed Apr 28 2006 To convert oxygen saturation values for salinity use correction factors based on chloride concentration or conductivity Refer to the manufac turer s instructions for the DO instrument before applying a salinity cor rection gt Correcting DO solubility for saline waters salinities greater than 2 000 microsiemens per centimeter or 1 000 mg L chloride varies with instrument type calibration method and the salts in solution gt The correction based on conductivity table 6 2 7 is more useful because accurate conductivity can be determined eas
250. onitoring site is lat 37 40 16 long 78 05 09 NAD83 which is at State Highway 45 at the Goochland Cumberland County line Va In 2004 one water quality monitoring station was added in the James River Basin This station is James River at Richmond Huguenot Bridge USGS station ID 02037500 and VDEQ 2 JMS117 35 In 2006 this station was moved downstream because of concerns over safety note that the stream gage was left at the Huguenot Bridge site This new station is James River at Boulevard Bridge at Richmond USGS station 02037618 and VDEQ 2 JMS113 20 The drainage area for this watershed is 6 776 mi The location of this monitoring site is lat 37931153 long 7792901 NAD83 in Richmond Va In 2005 the water quality monitoring station at the James River at the Blue Ridge Parkway USGS station 02024752 and VDEQ station 2 JMS279 41 was added The location of this monitoring site is lat 37 33 19 long 79 22 03 NAD27 in Amherst County Va The drainage area associated with this station is 3 076 mi In 2007 the water quality monitoring station located at the Chickahominy River near Providence Forge USGS station 02042500 and VDEQ 2 CHK035 26 was added The drainage area for this watershed 15 252 mi The location of this monitoring site is lat 3792610 long 7720340 NAD83 in New Kent County Va In 2011 the water quality monitoring station at the Rivanna River at Palmyra USGS station 02034000 and VDEQ 2 015 97 was ad
251. onwealth 20 of Virginia Department of General Services Division of Consolidated Laboratory Services DCLS 2544 Total Suspended Solids Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2590 Determination of Inorganic Carbon in Particulates of Estuarine Coastal Waters Using Elemental Analysis Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services Method 2591 Determination of Inorganic Phosphorus in Sediments and Particulates of Estuarine Coastal Waters Commonwealth of Virginia Department of General Services Division of Consolidated Laboratory Services A Comparability of Results The data collected for this program must be comparable and reproducible Therefore sampling methods and sample analyses must be uniform and consistent among the agencies collecting and analyzing the data This plan includes 1 a field component to assure that water quality samples are representative of river conditions and 2 a laboratory component to assess the variance accuracy and bias of analytical results The field component consists of documentation of field conditions collection procedures and equipment as follows 1 Water quality samples are collected using approved USGS guidelines to ensure the collection of samples that are representative of the river cross section These guidelines assure the collection of a representative com
252. or additional guidance Consult the manufacturer to address problems with a luminescent sensor instru ment Faulty batteries can cause erratic readings gt Check the voltage of the batteries gt Start with good batteries in the instrument and carry spares Table 6 2 3 Troubleshooting guide for amperometric instruments Symptom Possible cause and corrective action Instrument drifts or takes excessive time to stabilize Thermal equilibrium of water and sensor has not been reached wait longer Weak batteries replace DO sensor needs maintenance recondition Erratic instrument readings Break in cable replace cable Faulty connection at instrument or sensor clean contact and tighten Hole in membrane replace membrane recondition Air bubble in sensor recondition sensor Weak batteries replace Instrument too slow to react Gold cathode tarnished buff with pencil eraser and recondition sensor Fouled membrane replace membrane and recondition sensor Instrument will not read zero in sodium sulfite solution Solution contains oxygen make fresh solution Instrument still does not read zero replace membrane and recondition sensor Instrument cannot be cali brated to read standards Unable to adjust upward check to see in more than one membrane is on the sensor Unable to adjust downward membrane probably too tight or too thin replace membrane
253. orial and production support is extended to I M Collies and L J Ulibarri pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 SC 1 SPECIFIC ELECTRICAL 6 3 CONDUCTANCE By D B Radtke J V Davis and F D Wilde Page Specific electrical conductance 1 eee eere 5 3 6 3 1 Equipment and supplies eere 3 6 3 1 Conductivity 5 6 3 1 B Equipment maintance 6 6 3 2 2 4 4924 19 7 6 3 3 Measurement 11 6 3 3A Surface water 2 2 12 In situ measurement 4 cesse eese eene enean 12 Subsample measurement 14 6 3 3 B Ground 2 16 Downhole flowthrough chamber 16 Subsample measurement 18 6 3 4 Troubleshooting eee ee eee eere eee 19 6 3 5 e P PER eS EUS 21 Selected References 22 Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 Tables 6 3 1 Equipment and supplies used for measuring
254. ority of sediments are transported sediment samples will be collected following the standard USGS protocols for suspended sediment sampling and representative sampling USGS 1998 Locating the turbidity monitors at existing RIM stations provides several direct benefits to the study As the team that manages the RIM project for all Virginia stations we will integrate the current proposed study into the existing RIM program By doing this the proposed study will benefit from the historical body of data that has been collected at these stations and the existing understanding of these systems Additionally by co locating the turbidity probes with an established RIM station we can use the existing telemetry equipment to provide nearly free real time transfer and internet display of the turbidity data Lastly ongoing sediment and nutrient sampling at the RIM stations will defray many of the costs that would have been associated with sampling and maintaining equipment at any other location For example many of the costs associated with travel sampling laboratory costs and salary required by the proposed study will be paid for as part of the RIM project The following approach will be used at each monitoring station to calculate suspended sediment concentrations and loads on the basis of measured turbidity values e Continuously recording turbidity meters will be installed at each stream gage The turbidity meter must be installed in a location
255. ose times when it is impossible to take samples to the laboratory samples are refrigerated at 4 C and taken to the laboratory as soon as possible A Virginia Water Science Center field form is completed and kept on file in the Virginia Water Science Center as a record of the samples collected to check for final completeness of the analyses and to record field measurements date and time of collection and any unusual conditions Associated field data are entered into and sample analyses are scheduled using the VADEQ Comprehensive Environmental Data System CEDS Suspended sediment samples for RIM stations are collected in a 1 pint glass bottle labled and sent to the USGS sediment laboratory in Louisville Kentucky No preservation is necessary for suspended sediment samples 25 VI CALIBRATION PROCEDURES AND FREQUENCY Field parameters pH Specific Conductance Water Temperature Turbidity and Dissolved Oxygen are calibrated in the field using a YSI 6920 multiparameter instrument before field data are collected An equipment calibration log is kept with each multiparameter instrument This log records the date results of the calibration identification of standards initials of field person and any corrective actions taken Both pH and specific conductance standards are supplied by the USGS NWQL in Denver CO each standard has expiration dates posted on its container Calibration of laboratory equipment at VDCLS is documented in the public
256. others 1994 before being delivered to the laboratory for analysis Requirements set by the USEPA for regulatory laboratories state that nutrient samples be filtered within 24 hours and suspended solids determinations be performed within 7 days Samples collected on weekends are chilled to 4 C and held until they can be accepted by VDCLS the following week In some instances the analytical method for certain constituents differs for the total constituent and the dissolved constituent For each analytical method there is a range within which the actual concentration is expected so that it is possible for the analytical result of the total concentration of a particular constituent to be less than that of the dissolved concentration for that constituent Minimum reported concentrations may differ according to the detection limit depending on the specific technique done by the laboratory VDCLS has Standard Operating Procedures SOP for each laboratory analyte The reference for each laboratory analyte SOP can be found in Section III QA Objectives and Criteria The concentration of total nitrogen for this project is computed as the sum of particulate nitrogen and dissolved nitrogen for VDCLS samples and as the sum of dissolved nitrite plus nitrate nitrogen concentration and total ammonia plus organic Kjeldahl nitrogen concentration for NWQL samples Prior to February 1996 total nitrogen was computed as the sum of dissolved nitrite plus nitrate ni
257. ow and agitation and measurement accuracy decreases Wood 1981 When preparing to measure pH in low ionic strength waters the response time accuracy and reproducibility of the measurement can be improved by modifying the type of electrode and buffer To measure pH in water of low ionic strength 1 Use a specific low ionic strength electrode The pH electrode for low ionic strength solutions typically is characterized by e A thin responsive glass membrane A reference junction that allows rapid electrolyte flow and A pH neutral ionic additive within the reference filling solution 2 Use corresponding low ionic strength pH buffers The low ionic strength buffer should contain the same type of pH neutral ionic additive as that in the electrode reference filling solution the amount of pH neutral ionic additive must be the same in the electrode and buffer so that the net pH effect is standardized Low ionic strength buffers may not be of the standard pH buffer values pH 4 7 10 Check that your pH meter can accept these nonstandard buffer values for calibration Calibration of the pH instrument system and measurements made in low ionic strength solutions should involve a specific combination of low ionic strength buffers and low ionic strength electrodes Chapter A6 Field Measurements pH Version 2 0 10 2008 20 pH 6 4 3 C CALIBRATION FOR HIGH IONIC STRENGTH WATER USGS studies increasingly invo
258. pe and whether or not they are themselves NIST traceable 3The cost of commercial calibration services can vary widely Examples of laboratories that are accredited to perform thermometer calibrations and certification include National Institute of Standards and Technology http ts nist gov ts htdocs 230 233 calibrations ICL Calibration Laboratories www icllabs com Lab Safety Supply Inc https www labsafety com calibration URLs cited were accessed 11 28 2005 Chapter A6 Field Measurements Temperature Version 2 3 2006 require regular accuracy checks against a calibration thermometer Carry an extra thermometer in the event that the accuracy of a field thermometer is in question Note however that field checking of a thermometer s accuracy does not substitute for the required annual laboratory calibration gt Ata minimum calibrate each field thermometer every 12 months the time interval depends on the amount of use and abuse to which the thermometer has been subjected and on its manufacture According to thermometer manufacturers some models of thermistor thermometers require calibration every 6 months YSI 2005 Quarterly or possibly monthly calibration can be required if the thermometer is in heavy use was exposed to thermal shock an extended period of direct sunlight or extreme shifts in temperature or was exposed to aggressive chemical solutions The calibration history from the log book can indicate t
259. ple and measure turbidity Dynamic Determination Cross sectional variability At a field site measure turbidity at a number of verticals across the stream width see NFM 4 and 6 0 Compare against measurements at the centroid stream margins locations for continuous monitors different depths or against a static measurement from a composite sample using a meter that is optically compatible with the dynamic meter Keep in mind that the static measurement will likely be biased low if sand or coarse silt are present Measurement variability At a field site repeat turbidity measurements three or more times at the same location one after another Record these values after removing the meter from the water Use the same instrument for each set of measurements Consider submitting samples for laboratory analysis Operator variability At a field site have two or more people determine turbidity at the established measurement location Use the same instrument for each set of measurements although it can be calibrated by each person independently to incorporate all sources of variability If sand or coarse silt are present in the sample qualify your static determination data being entered into NWIS with an E remark code Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 49 BIAS 6 7 4 Sources of bias can include effects on measurements from various properties of water table 6 7
260. ples therefore are collected using approved USGS protocols for water quality sampling ensuring that water quality conditions are represented as closely as possible Water quality samples are collected during baseflow by the VDEQ at the James River at Blue Ridge Parkway and Rivanna River stations and by USGS all other sites during baseflow and stormflow conditions The USGS collects all water quality samples using an equal width increment EWI method so that a sample representative of stream conditions is obtained EWI method in which samples are collected at centroids of equal width increments of the stream is used most often in shallow or sandbed streams where the distribution of water discharge in the cross section is not stable or in streams where the distribution of discharge in the cross section is unknown Samples are collected using a USGS designed depth integrating sampler designation DH 95 or D 96 when average streamflow velocities exceed 1 5 ft s or a weighted sample bottle 96 at lower velocities when depth integrating samplers are not effective A depth integrating sampler is designed to sample the vertical water column of the river proportionally to the velocity at each depth These methods are documented by Edwards and Glysson 1988 and Ward and Harr 1990 The VDEQ collects all water quality samples using a single depth integrated or depth and width integrated techniques For further details on the VDEQ sampl
261. pling and analysis approximately 10 percent of the samples will be made up of quality control samples such as blanks and duplicate samples Additional detailed information regarding the laboratory methods and analyses performed by DCLS are available in the form of a Project specific QAPP that is submitted to the Chesapeake Bay Program annually During the collection of all water quality samples a project specific field form will be used to document the specific environmental conditions under which each sample was collected In the field this form will be the responsibility of the lead technician collecting samples Upon returning to the Virginia Water Science Center the field form will be delivered to the Virginia Water Science Center Data Manager for entry into the USGS water quality database Standard data flow practices within the Virginia Water Science Center have been documented in the Virginia Water Science Center s Quality Assurance Plan for Water quality Activities USGS 2003 This quality assurance plan documents the processing of all data collected within the office including sample handling and tracking data management as well as data review and publication Similar to the review of all continuous water quality data at the end of a given water year all discrete water quality data will be reviewed at the end of the water year and published in the Annual Virginia Water Science Center Data Report after these data have been finali
262. posite sample from the horizontal and vertical cross section of the river 2 Sampling criteria based on flow characteristics are documented for field personnel to ensure that water quality samples are collected over a range in flow conditions In addition detailed recording of field procedures ensures consistency of procedures between field personnel 3 Proper use of sampling and monitoring equipment and sample collection techniques by field personnel is verified with in house testing field audits of field procedures 4 Proper cleaning procedures of sampling equipment is documented through ongoing comparisons of field and equipment blanks scheduled as in Appendix 1 21 The laboratory component of this plan consists of the collection and analysis of duplicate and standard reference samples as follows and as scheduled in Appendix 1 1 Concurrent Replicate samples are used to document the variance of the analytical results Replicate samples are prepared by collecting to concurrent samples Both samples are then analyzed by VDCLS The second subsample is disguised as an environmental sample by labeling it with a different time from the first subsample 2 Standard reference samples document the ability of a laboratory to accurately analyze samples of known concentrations and to check for bias in analytical results Standard reference samples are prepared in the USGS laboratory and submitted to VDCLS and NWQL for analysis In ad
263. r no flow quiescent sample conditions When using a single parameter meter the measurement can be made either with the pH electrode and temperature sensor inserted a into an airtight flowthrough cell or chamber to which the sample is pumped or b in a vessel that contains an aliquot of sample either collected from pump discharge or withdrawn from a sampling device such as a bailer figs 6 4 2 and 6 4 3 respectively See 6 8 for pH measurement using a multiparameter sonde The central concept for measuring pH in ground water is to use equipment that minimizes aeration chemical change and temperature change If possible operate equipment in a manner that helps to mitigate losses and gains of dissolved gases in solution gt The flowthrough cell chamber method yields accurate pH data when implemented appropriately gt Bailed or other methods for collecting discrete samples for pH measurement must be implemented carefully to avoid temperature change turbulence and sample aeration from decanting and mixing of the bailed water gt Downhole deployment of a submersible sensor or sonde risks losing the equipment if it becomes lodged in the well Document on electronic or paper field forms the methodology used to obtain samples for pH measurement Unless specifically required by study objectives or environmental constraints in situ measurement of pH by putting the sensor system directly into the well downhole method
264. r the samples report the median of 3 or more samples and record this difficulty in field notes 10 Rinse the sensor the thermometer and the container with deion ized water If another measurement is to be made within the next day or two store the sensor in deionized water Otherwise store the sensor dry Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 16 5 6 3 3 B GROUND WATER Measurements of ground water conductivity must represent aquifer conditions Temperature changes resulting from transporting a well sample to land surface can affect conductivity gt To minimize the effect from temperature changes measure conductivity as close to the source as possible using either a downhole or flowthrough chamber sampling system refer to 6 0 for details gt Bailed or other methods for collecting discrete samples isolated from the source are not recommended as standard practice although such methods are sometimes called for owing to site characteristics or other study requirements The well should be purged or in the process of purging before sample conductivity is determined and recorded Downhole and flowthrough chamber measurement 1 Calibrate the conductivity instrument system on site e Bring standard solutions to the temperature of the water to be sampled by suspending the standards in a bucket into which well water is flowing Allow at least 15 minutes for temp
265. ratory practices are required in order to achieve consistent results Always use turbidity free water deionized water passed through a filter media of less than or equal to 0 2 um at 20 25 for mixing dilutions or suspensions Prepare the stock turbidity suspension monthly and calibrant dilutions immediately prior to instrument calibration Calibrant solutions made from diluted scratch formazin are stable for only a few hours to a few days depending on the concentration ASTM 2003b With the exception of 4 000 NTU formazin commercial calibration solutions such as StablCal or AMCO AEPA 1 must not be diluted because changes will occur in the suspension matrix that will render the dilutions nonlinear Store reagents as appropriate in a dust free cabinet or refrigerator Inconsistent techniques used to dilute calibrants and variable temperatures can add significant measurement error Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 25 To prepare a 4 000 turbidity unit formazin stock suspension 1 Wearing laboratory powderless disposable gloves quantitatively transfer 5 0 g of reagent grade hydrazine sulfate NH5 H550 into approximately 400 mL of turbidity free water in a 1 L volumetric flask 2 Quantitatively transfer 50 0 g of reagent grade hexamethylenetetramine CH5 gN4 into approximately 400 mL of turbidity free water in a separate clean flask stopper and swirl un
266. rd keeping when cleaning and calibrating continuously deployed instruments and for acceptable tolerances Monitor the output carefully to ensure that turbidity readings are stable before confirming the calibration gt Calibrate the instrument using calibration turbidity solutions before leaving for the field While in the field check instrument performance periodically using a calibration or verification calibrant and turbidity free water gt The optical surface of the sensor must be clean before beginning the calibration procedure In deployed continuous monitoring situations pipes or other structures that house the sensor also may require periodic cleaning To calibrate a submersible turbidity sensor modify the general instructions that follow as necessary so that they are compatible with the manufacturer s instructions Prepare a sufficient volume of the selected calibration solution or verification calibrant as described previously The volume of cali brant required could be 500 mL for some instruments particularly if the entire sonde bundle will be immersed 2 Select Procedure A or B The same procedure once tested and selected also should be applied to instruments used in future studies against which the data could be compared Procedure Immersion of the entire sonde bundle of field measurement sensors including the turbidity sensor requires larger volumes of calibrant calibrant is vulnerable to contam
267. re If Yes go to step 3 fig 6 7 2 If No continue to step 2 fig 6 7 2 If the study involves regulation of drinking water the instrument choices are limited by the methods accepted by the USEPA for drinking water If the study involves State regulations for exam ple those proposed under provisions of the Clean Water Act the regulations may require the use of one or more specific instrument designs which cannot be anticipated in this protocol If the study does not involve turbidity in drinking water or other specially designated instrument types consider using instrument designs that accommodate a broader range of environmental conditions 2 Whatis the expected range in turbidity or what part of the range is most important to measure accurately For turbidities in the range of 0 1 000 units single detector nephelometric measurement may work adequately if the instrument is calibrated in the same range as the sample As particle densities increase however the backward scattering of light particles increases to the point that it can cause interference with single detector nephelometry resulting in a negative effect on the measurement or an unstable reading table 6 7 1 Multiple detectors at different angles can be used with the turbidity value determined by a ratio of the light received by the different detectors Ratioing helps to reduce noise in the turbidity signal especially at ultra low turbidities or wh
268. re Version 2 3 2006 U S Geological Survey TWRI Book 9 T 15 6 1 3 8 SURFACE WATER The reported surface water temperature must be measured in situ do not measure temperature on subsamples from a sample compositing device Measure temperature in such a manner that the mean or median temperature at the time of observation is represented consult NFM 6 0 and fig 6 0 1 Record any deviation from this convention in the data base and report it with the published data To measure the temperature of surface water gt Making a cross sectional temperature profile first to determine the temperature variability of the stream section is recommended a hand held digital thermometer works best for this purpose gt To determine which sampling method to use NFM 6 0 examine the cross sectional profile and consider study objectives gt Measure temperature in those sections of the stream that represent most of the water flowing in a reach Do not make temperature measurements in or directly below stream sections with turbulent flow or from the stream bank unless this specifically represents the intended condition to be monitored 1 Use either a liquid in glass thermometer or a thermistor thermom eter tagged as office laboratory certified and dated within the past 12 months 2 Record on field forms the temperature variation from the cross sectional profile and the sampling method selected e Flowing shallow stream
269. rence in pH between the Junction solutions on both sides of the glass bulb AgCI covered silver wire Glass electrode internal solution shown within the glass bulb Figure 6 4 1 Diagram of a combination single junction pH electrode Modified from pH meter info 2005 pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 gt Electrode performance naturally degrades over time with normal use However field personnel need to be alert to those chemical environments that can cause serious and more rapid degradation of electrode performance IC Controls 2005a Many such environments are coincident with industrial mined and urban areas table 6 4 2 Field personnel should be aware of the effect on the pH measurement when deploying the electrode in such environments document field conditions on field forms When measuring pH under specific adverse chemical conditions the use of electrodes with properties designed to withstand such conditions is recommended table 6 4 2 pH 7 Table 6 4 2 pH electrodes recommended for water having elevated concentrations of sodium and other monovalent major cations sulfide cyanide and ferric chloride H hydrogen ion Na sodium ion greater than 2 greater than or equal to Chemical condition Description of water Degradation effect on a common combination pH electrode Recommended pH electrode Basic ions dominant in
270. ret ee ore beo seset teresse 8 6 7 2 Decision tree to determine appropriate instrumentation designs for intended turbidity 8 14 Tables 6 7 1 Properties of water matrices and their expected effect on turbidity 6 6 7 2 Sampling interferences and their expected effect on turbidity 1 1 6 6 7 3 Summary of instrument designs and capabilities current reproducible technologies appropriate applications and approximate limits 7 6 7 4 Reporting units corresponding to turbidity instrument designs ce eeee teen ee esee en 10 6 7 5 Equipment and supplies used for measuring 19 6 7 6 Guidelines for reporting turbidity units 51 6 7 7 Troubleshooting guide for field turbidity MEASUTEMENL sa paseo eoo 52 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 3 TURBIDITY 6 7 Turbidity which can make water appear cloudy or muddy is caused by the presence of suspended and dissolved matter such as clay silt finely divided organic matter plankton and other microscopic organisms organic acids and dyes ASTM International 20032 The color of w
271. rodes and buffer solutions pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 5 Table 6 4 1 Equipment and supplies used for measuring mL milliliters mV millivolt degrees Celsius uS cm microsiemens per centimeter at 25 degrees Celsius plus plus or minus MSDS Material Safety Data Sheets v meter and pH electrodes Battery powered solid state with automatic temperature compensation for multiparameter instruments see 6 8 Range of at least 2 to 12 pH preferably 0 to 14 pH Accuracy of at least 0 01 units Temperature range of at least 0 to 45 Millivolt readout with accuracy of 1 0 mV pH electrodes gel filled or liquid filled as appropriate for study objectives and site conditions pH electrode filling solution of appropriate composition and molarity for liquid filled electrode pH electrode storage solution Thermistor or thermometer calibrated Buffer solutions for pH 4 7 and 10 temperature correction chart s for buffers labeled with expiration dates Stand for holding pH electrode Bottle delivery squeeze to dispense deionized water Deionized water maximum conductivity of 1 uS cm A So 50 5 UG Beakers or measurement vessels polyethylene or Teflon preferable assorted volumes of 50 to 150 mL clean but not acid rinsed Flowthrough chamber for ground water measurements Minnow bucket or mesh bag with tether or equivalent used
272. ructions for a which buffers to use and b the sequence of buffer use EXAMPLE When measuring pH in a stream that is within the normal range of specific electrical conductivity a If pH values are expected to be between 7 and 8 then the standard pH 7 and pH 10 buffers should be selected b If pH values are expected to be less than 7 then the standard pH 7 and pH 4 buffers should be selected c Iftheanticipated pH range in pH is large a check of electrode performance using a third standard buffer value is advisable The following guidelines and standard procedures apply in general whenever a pH instrument system is to be calibrated Because calibration and operating procedures can differ with differing instrument systems check the manufacturer s recommended calibration procedures and calibration solutions Digital pH meters automatically compensate for buffer temperatures and indicate appropriate Nernst values in millivolts When using these instruments follow the manufacturer s calibration instructions precisely do not take shortcuts gt Before each field trip and field calibration check pH meter electrode logbook records for electrode performance Remember any noted calibration slope of 95 percent or less indicates probable electrode deterioration at 94 percent slope or less the electrode should not be used gt Use at least two pH buffer solutions of documented traceable pH value for adequate calibration of the pH in
273. s p 137 161 1985 Study and interpretation of chemical characteristics of natural water 3d ed U S Geological Survey Water Supply Paper 2254 p 66 69 Rainwater F H and Thatcher L L 1960 Methods for collection and analysis of water samples U S Geological Survey Water Supply Paper 1454 p 275 278 Roberson C E Feth J H Seaber P R and Anderson Peter 1963 Differences between field and laboratory determinations of pH alkalinity and specific conductance of natural water U S Geological Survey Professional Paper 475 C p C212 C215 U S Geological Survey variously dated National field manual for the collection of water quality data U S Geological Survey Techniques of Water Resources Investigations book 9 chaps A1 A9 available online at http pubs water usgs gov twri9A Wilde F D Radtke D B Gibs Jacob and Iwatsubo R T eds September 1999 Collection of water samples U S Geological Survey Techniques of Water Resources Investigations book 9 chap A4 accessed Sept 20 2005 at http pubs water usgs gov twri9A4 Wood W W 1981 Guidelines for collection and field analysis of ground water samples for selected unstable constituents U S Geological Survey Techniques of Water Resources Investigations book 1 chap D2 p 11 Specific Electrical Conductance Version 1 2 8 2005 U S Geological Survey TWRI Book 9 DO 1 DISSOLVED OXYGEN 6 2 Revised by Michael E Lewis Page D
274. s Nernstian relation the slope along any two points on the line plotted for electrical potential versus pH is known to be 59 16 mV pH units To calculate the slope between two points along the line of measured potentials versus pH E E S pH where S slope E electrode pair potential in mV and E standard potential in mV Thus using two buffers of known pH pH and E E S pH and E5 E S pH gt Rearrange as ae E pH The theoretical slope is temperature dependent the theoretical slope in mV can be calculated as S 0 19841 273 15 t where t temperature in degrees Celsius and S slope at a given temperature pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 The primary concept in accurate calibration of the pH electrode is to select pH buffers with values that bracket the expected pH of the environmental sample this is known as a two point calibration Before field calibration of the pH instrument system it is useful to estimate or to anticipate from historical site data if available the pH and conductivity of the waters to be encountered at the field sites If no data are available from which to estimate sample pH then pH indicator paper can be used onsite as a gross indicator of the pH of the system Under no circumstances should a pH value from indicator paper be recorded as site pH For three point or other multipoint calibrations follow the manufacturer s inst
275. s are those that are used to adjust instrument readout and must be traceable and equivalent to the reference turbidity calibrant to within accepted statistical errors Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 22 TBY TECHNICAL NOTE 4 Acceptable calibration turbidity solutions include dilutions of formazin made from scratch scratch formazin commercially prepared stabilized formazin such as StablCal available from Hach Company in formulations of 4 000 turbidity units and lower and styrene divinylbenzene beads SDVB such as AMCO AEPA 1 polymer Although stabilized formazin calibrants have a much longer shelf life than solutions diluted from scratch formazin settling of formazin crystals can still be observed when they sit unused Calibrants made from SDVB have a more uniform grain size than formazin and tend to settle less over time but often are custom developed for specific instruments and must be purchased accordingly gt Calibration Verification calibrants are those used to perform instrument checks in the field Calibration verification calibrants may include but are not limited to calibration turbidity solutions Sealed or solid materials should not be used to adjust instrument performance Calibration turbidity solutions and calibration verification calibrants be instrument specific Be careful to check the manufacturer s instructions Use of calibrants with instruments for
276. s estimated for rivers at the Fall Line can therefore be used as single point sources of loads to the Chesapeake Bay The monitoring program was expanded over the years to include smaller basins that are tributary to the Potomac Rappahannock Pamunkey and James Rivers Loads of nutrients and suspended solids are greatest during stormflow conditions because of higher discharge and often higher constituent concentrations Therefore the monitoring program was expanded in 1988 to include more frequent water quality data collection during stormflow conditions at two major Virginia tributaries to the Chesapeake Bay the James and Rappahannock Rivers In July of 1989 the Pamunkey Mattaponi and Appomattox Rivers were added to this storm monitoring network In July of 2004 the North and South Fork Shenandoah Rapidan and James at Richmond at the Huguenot Bridge Rivers were added to the storm monitoring network In 2005 the James River at the Blue Ridge Parkway was added to the storm monitoring network DEQ continues to collect the monthly scheduled sample at the Blue Ridge Parkway Site Also in 2005 the USGS began monthly monitoring of water quality conditions at the North and South Fork Shenandoah and Rapidan Rivers In 2006 the James River at Richmond station was moved from the Huguenot Bridge to the Boulevard Bridge for safety reasons note that the stream gage was left at the Huguenot Bridge site In 2007 the USGS began monthly and storm monitor
277. s for selected unstable constituents U S Geological Survey Techniques of Water Resources Investigations book 1 chap D2 24 p YSI 2005 Temperature FAQs How do thermistors fail what typical failure modes for thermistors accessed December 16 2005 at http www ysitemperature com med faq html 4 Chapter A6 Field Measurements Temperature Version 2 3 2006 22 T ACKNOWLEDGMENTS This National Field Manual responds to advances in technology and science and to the developing needs for water quality monitoring Its aim is to provide scientifically sound guidance to USGS personnel and to document USGS requirements for collecting water quality data As a result the expertise of numerous scientists has been tapped in developing this manual and keeping it current great debt of gratitude is owed to the following original authors editors and reviewers of Chapter A6 Section 6 1 of this field manual M E Brigham E A Ciganovich I M Collies J V Davis C M Eberle R J Hoffman R T Iwatsubo J K Kurklin R J LaCamera V W Norman C E Oberst B B Palcsak K A Pearsall D B Radtke F C Wells Chester Zenone and the analysts of the USGS National Water Quality Laboratory Special appreciation is extended to our colleagues and collaborators from the Hach In Situ Inc and YSI Inc companies Improvements to the technical quality of this revision of Section 6 1 Temperature can be attributed to the expertis
278. s much as possible Use the oxygen solubility table 6 2 6 to determine the DO satura tion at the measured temperature and atmospheric pressure Refer to section 6 2 5 and table 6 2 7 for salinity corrections Following the manufacturer s instructions adjust the calibration control until the instrument reads the DO saturation value deter mined from the oxygen solubility table Verify that the instrument reading is within 0 2 mg L of the computed saturation value or use more stringent accuracy criteria that reflect the data quality requirements of the study The luminescent sensor instrument is now calibrated and ready for use When working with an amperometric instrument remove the sen sor from the calibration chamber and check to see if any water droplets are on the membrane Water droplets on the membrane cause improper calibration If water droplets are present recalibrate the instrument otherwise the instrument is now calibrated and ready for use Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 15 Procedure 2 Calibration with air saturated water In this procedure the DO sensor or instrument system is calibrated against water that is saturated with oxygen at a known temperature and ambient atmospheric pressure 1 The temperature of water used for calibration should be about the same as the temperature and conductivity of the water to be mea sured e If working at the f
279. s per liter NFM National Field Manual for the Collection of Water Quality Data minus plus degrees Celsius and plus or minus Amperometric instrument must be temperature and pressure compen sated Amperometric instrument DO sensor membrane replacement kit includes membranes O rings filling solution For amperometric or luminescent sensor methods Y DO instrument and DO sensor or multiparameter instrument with DO capability and digital temperature readout display Operating range at least 5 C to 45 Measure concentrations 0 05 to 20 mg L Minimum scale readability preferably 0 01 mg L DO Calibrated accuracy within 0 2 mg L DO Calibration chamber per manufacturer s recommendation Pocket altimeter barometer calibrated measures to nearest 1 millimeter Thermometer see NFM 6 1 for selection and calibration criteria Zero DO calibration solution dissolve 1 gram sodium sulfite and a few crystals of cobalt chloride in 1 liter deionized water Flowthrough chamber for determining DO in ground water Oxygen solubility table table 6 2 6 Waste disposal container or equivalent 5555 ON RN Spare batteries lt Calibration and maintenance log books for DO instrument barom eter Modify this list to meet specific needs of the field effort Prepare fresh zero DO solution before each field trip Chapter A6 Field Measurements Dissolved Oxygen Version 2 1
280. serting the cell containing calibrant into the instrument ensure that no air bubbles are present in the cell If necessary degas the sample according to manufacturer s instructions Air bubbles can cause significant positive bias in turbidity measurements table 6 7 1 Orient the calibration cell in the cell holder according to the index marks the calibration cell and sample cell must have identical orientation when in the instrument measurement chamber In the instrument logbook record the instrument value for each calibrant Most modern turbidimeters contain calibration curve fitting capabilities specific to that instrument allowing the instrument to produce sample readings that may be used directly If the meter does not have this capability you will need to construct a calibration curve to correct sample readings to the calibrated turbidity To determine turbidity using a calibration curve see American Public Health Association 2001 for more details on this procedure Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 29 a Record the instrument response to a range of calibration solutions bracketing the expected turbidity of the sample b Create a graph showing the value of the instrument response x axis against the turbidity value of the calibration solutions y axis c Using linear regression plot a line that encompasses the plotted values d For water samples input the instrument readi
281. sheet that details field conditions and field parameter values is completed for each sampling trip and kept in the USGS Office along with a copy of the analytical services request forms The field parameter values are entered into the Virginia Water Science Center QWDATA water quality data base at the office Water quality analyses performed are stored on the USGS Virginia Water Science Center QWDATA water quality data base Raw data are published in the USGS Annual Report for Virginia The appropriate data originator is notified of errors so that the source data bases can be corrected and thus remain consistent with all others 28 IX INTERNAL QC CHECKS A Field The quality assurance practices of field procedures include documentation of cross section depth integrated variability quality assurance of field personnel documentation of field sampling status and collection of field equipment and laboratory blanks These practices are described in greater detail in Section III B Laboratory VDCLS The quality assurance practices of VDCLS including quality control quality assurance of analytical results quality assurance of all materials used in the preservation and containment of water quality samples and the blind reference sample quality assurance program are documented in Quality Assurance Plan for the Virginia Division of Consolidated Laboratory Services In each laboratory analyte SOP see section III QA Objectives and Criteria t
282. so is a strong reducing agent and as such requires standard laboratory safety precautions avoid inhalation ingestion and contact with skin and work in a fume hood In water it separates into free hydrazine and sulfuric acid An excess of hexamethylenetetramine reacts with acid to produce formaldehyde at neutral pH The formaldehyde then reacts with dissolved hydrazine to produce the formazin polymer The final product 4 000 turbidity unit formazin suspension contains 3 2 parts per million hydrazine sulfate 0 1 percent formaldehyde 0 2 percent formazin 0 5 percent ammonium sulfate and 4 7 percent hexamethylenetetramine Laboratory rats were fed 4 000 NTU formazin at 5 000 mg kg body weight with no toxic effect Sadar and others 1998 Avoid inhalation and ingestion of or skin contact with hydrazine sulfate when preparing formazin solutions Work in a fume hood Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 24 TBY 6 7 2 A CALIBRATION SOLUTION USE PREPARATION AND DILUTION A stock formazin solution may be prepared in the laboratory or may be purchased from a manufacturer Serial dilutions are made to achieve the desired calibration interval Commercially prepared calibration turbidity solutions are recommended for routine instrument calibration to avoid any safety and quality assurance concerns Under circumstances in which study personnel need to prepare a stock turbidity suspension precise labo
283. solution pH high gt 10 pH units low H Sluggish response to changes in Glass pH electrode activity results in measurement pH resulting from dehydration designed for measuring of other monovalent ions in of the glass membrane high values of pH solution Sodium effect The pH measurement is Glass pH electrode Elevated Na at pH 211 0 H negatively biased designed for measuring activity is low The electrode high values of pH senses Na activity as if it were H because of the similar charge and structure of the Na and H ions Elevated concentrations of sulfide or cyanide Elevated concentrations of sulfides or cyanides are found in industrial mined or urban areas Sulfide or cyanide contamination of the internal reference electrode Double junction electrodes and plasticized reference electrodes Elevated concentration of ferric chloride Ferric chloride is used as a flocculating agent in wastewater treatment plants for example Ferric chloride attacks the glass membrane of the pH electrode deactivating many of the sensing sites on the glass surface Consult the manufacturer for 1 selecting pH electrodes that can withstand this environment and or 2 specific cleaning procedures for the glass membrane Glass membrane The most essential and vulnerable element of the pH electrode is the sensitive glass membrane which permits the sensing of hydrogen ion ac
284. sor mem brane e Insert the DO sensor into the wet chamber this ensures 100 percent humidity e Ifa YSI model 5739 sensor is used the pressure compensating diaphragm on the side of the sensor must be enclosed within the calibration chamber during calibration e Check that no water can leak into the calibration chamber and that the membrane does not have droplets of water adhering to it The water droplets reduce the rate of oxygen diffusion through a membrane producing erroneous results 2 Immerse the calibration chamber into the water to be measured Allow 10 to 15 minutes for the air temperature inside the chamber to equilibrate with the water see the TECHNICAL NOTE in Proce dure 1 e For streams choose an area of the stream that closely approxi mates mean stream temperature In shallow streams try to place the chamber in an area that represents the stream but that is shaded from direct sunlight e For ground water use temperature stabilized purge water or other clean water having a temperature that closely approxi mates that of the ground water Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 18 DO Water droplets on the DO membrane will result in improper calibration Recalibration is required if water droplets are observed 3 Using acalibration checked pocket altimeter barometer determine the ambient atmospheric pressure to the nearest 1 mm of mercury 4 Read the temperatur
285. sources Investigations book 9 chap A6 section 6 8 August available online only at http water usgs gov owq FieldManual Chapter6 6 8 contents html Accessed October 23 2008 pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 29 Hem J D 1989 Study and interpretation of the chemical characteristics of natural water 3d ed U S Geological Survey Water Supply Paper 2254 p 61 66 IC Controls 2005 pH theory amp measurement IC Controls Technical Notes Issue 6 1 available online at www iccontrols com files 6 1 pdf Accessed September 5 2008 IC Controls 2005b Pure water pH measurement in low conductivity samples IC Controls Applications Notes Issue 6 2 available online at www iccontrols com files 6 2 pdf Accessed September 5 2008 Lane S L Flanagan Sarah and Wilde F D 2003 Selection of equipment for water sampling ver 2 0 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A2 March available online only at http pubs er usgs gov usgspubs twri twri09A2 Accessed October 23 2008 Nordstrom D K and Alpers C N 1999 Negative pH efflorescent mineralogy and consequences for environmental restoration at the Iron Mountain Superfund site California Proceedings of the National Academy of Sciences v 96 p 3455 3462 Orion Research Inc 1982 Handbook of electrode technology Cambridge Mass Orion Research Inc p 2 4 P
286. stall the DO equipment see NFM 6 0 e Downhole system Lower the DO and temperature sensors to the sampling point followed by the pump to monitor DO varia tion during purging If an amperometric downhole system will be used only for final DO determination after the samples are collected and the pump is removed attach a stirrer to the DO instrument before lowering it to the sampling point e Flowthrough chamber system Refer to NFM 6 0 for installation guidelines Be sure to Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 23 a Install the DO sensor through an air tight grommet checking that the seal is intact Check that the sensors are properly immersed b Flush air bubbles from the tubing walls and flowthrough chamber tap the tubing with the blunt end of a tool to dislodge entrained air bubbles see TECHNICAL NOTE below c Check for and eliminate backpressure in the chamber 3 If using a luminescent sensor instrument skip to step 4 If using an amperometric instrument be sure to maintain constant laminar flow past the DO sensor 4 Measure and record DO at regular intervals throughout purging Allow the sensors to equilibrate with ground water for 5 minutes or more at the flow rate to be used for sampling 5 Check the stability variability of DO toward the end of purging The stability criterion is met when five consecutive readings made at regularly spaced intervals of
287. steps 1 through 15 below apply to most instruments used for field measurements check the instrument manual for specific instructions 1 Inspect the instrument and the conductivity sensor for damage Check the battery voltage Make sure that all cables are clean and connected properly 2 Turn the instrument on and allow sufficient time for electronic stabilization Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 8 SC 3 Select the correct instrument calibration scale for expected con ductivity 4 Select the sensor type and the cell constant that will most accu rately measure expected conductivity 5 Select two conductivity standards that will bracket the expected sample conductivity Verify that the date on the standards has not expired 6 Equilibrate the standards and the conductivity sensor to the tem perature of the sample e Put bottles of standards in a minnow bucket cooler or large water bath that is being filled with ambient water e Allow 15 to 30 minutes for thermal equilibration Do not allow water to dilute the standard 7 Rinse the conductivity sensor the thermometer liquid in glass or thermistor and a container large enough to hold the dip type sen sor and the thermometer e First rinse the sensor the thermometer and the container three times with deionized water e Next rinse the sensor the thermometer and the container three times with the st
288. structed Check age expiration of calibrant solutions Check accuracy against that of another instrument Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 53 SELECTED REFERENCES American Public Health Association 2001 2130 B Turbidity in Clesceri L S and others ed Standard Methods for the Examination of Water and Wastewater 20th Edition Washington D C American Public Health Association p 3 ASTM International 2003a D1889 00 Standard test method for turbidity of water in ASTM International Annual Book of ASTM Standards Water and Environmental Technology 2003 v 11 01 West Conshohocken Pennsylvania 6 p ASTM International 2003b D6855 03 Standard test method for determination of turbidity below 5 NTU in static mode ASTM International Annual Book of Standards Water and Environmental Technology v 11 01 West Conshohocken Pennsylvania Backhus D A Ryan J N Groher D M MacFarlane J K and Gschwend P M 1993 Sampling colloids and colloid associated contaminants in ground water Ground Water v 31 no 3 p 466 479 Christensen V G Jian X and Ziegler A C 2000 Regression analysis and real time water quality monitoring to estimate constituent concentrations loads and yields in the Little Arkansas River south central Kansas 1995 99 U S Geological Survey Water Resources Investigations Report 00 4126 36 p accessed March 2
289. strument system gt Pour the amount needed of each buffer from the source container into a clean polyethylene bottle dedicated for the respective buffer and label the bottle with the buffer s pH value lot number expiration date and the temperature adjusted pH values provided by the manufacturer for that buffer gt The temperature of the buffer solutions should be near the same temperature as the water to be sampled A calibration check of the temperature sensor must be performed at least annually NFM 6 1 TECHNICAL NOTE Temperature has two effects on the pH measurement of a sample temperature can affect meter and electrode potentials Nernstian slope effect and it can change hydrogen ion activity chemical effect within the sample The electrode potential problem can be solved by using an automatic or manual temperature compensator The change in hydrogen ion activity resulting from temperature changes in the sample will be minimized if the electrodes buffers and container are allowed to equilibrate to the same temperature Do not use pH buffers that have exceeded their date of expiration pH 15 Chapter A6 Field Measurements pH Version 2 0 10 2008 16 pH 6 4 3 A CALIBRATION PROCEDURE UNDER STANDARD AQUEOUS CONDITIONS Standard aqueous conditions refers to environmental water with an ionic strength that is within the range in which a standard buffer solution and combination pH electrode can be appropria
290. subsamples will be measured collect sample aliquots in separate field rinsed bottles fill to the brim cap tightly and maintain at ambient ground water temperature Mea sure conductivity as soon as possible 3 Follow procedures described in steps 4 through 10 for Subsample measurement of surface water 6 3 3 A TECHNICAL NOTE If the sample is measured in an open container and readings do not stabilize within several minutes the cause may be C0 degassing use a closed system to measure the sample Filter the conductivity sample if the settling of clay particles appears to interfere with the stability of the readings TROUBLESHOOTING 6 3 4 Contact the instrument manufacturer if the actions suggested in table 6 3 4 fail to resolve the problem gt If available use a commercial electronic calibrator to check the function of conductivity instruments Check the voltage of batteries Always have good batteries in instruments and carry spares Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 20 5 Symptom Table 6 3 4 Troubleshooting guide for conductivity measurement hydrochloric acid degrees Celsius Possible cause and corrective action Will not calibrate to standards Standards may be old or contaminated use fresh standards Electrodes dirty clean with a detergent solution then with 5 percent Before using any acid solution t
291. t carry a current NIST certification or NIST traceable certification that is no more than 2 years old The actual duration of the calibration depends on the date of thermometer certification not the date of pur chase how frequently the thermometer is used and the conditions thermal chemical and physical to which it has been subjected dur ing field operations and storage see Maintenance cleaning and stor age in section 6 1 1 gt Check that the calibration thermometer has NIST certification or traceable certificate that is within a 2 year period of original certification or recertification gt Liquid in glass calibration thermometer Before each use inspect the thermometer for cracks internal condensation and liquid separation if any of these condi tions are observed the thermometer must be replaced If the thermometer has been stored or used improperly exposed at some length to sunlight or heat or if its accuracy is otherwise in question check its readings at tempera tures of approximately 0 25 and 40 C against those of another calibration thermometer that has been certified within the past 2 years If the environmental air or water temperatures to be measured fall below or exceed this range add calibration points to bracket the anticipated temperature range Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 T 9 Thermistor calibration thermometer Before ea
292. t is in use Check the relative accuracy of the turbidity measurement before leaving for the field by inserting calibration turbidity solutions covering the FAU range needed Accounting for a change in reporting units calibration steps for spectrophotometric determination are identical to those for static measurement of turbidity including the possible need for constructing a calibration curve see instructions under Benchtop static turbidimeter calibration steps 1 through 8 Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 33 MEASUREMENT 6 7 3 Three methods for field measurement determinations of turbidity are described in this section static or benchtop determination 6 7 3 A dynamic submersible determination 6 7 3 B and spectrophotometric absorptometric determination 6 7 3 C Procedures for the use of turbidity instruments are similar for various surface water and ground water applications The sampling methods used and the considerations needed for accurate representation of the intended water conditions however depend on the objectives and intended data use of the study and on site type and conditions Routine sampling of streams by the USGS typically involves isokinetic depth integrated sampling methods NFM 4 1 NFM 6 0 2 Much of the routine sampling of ground water at wells by the USGS involves well purging NFM 4 2 NFM 6 0 3 Before making a turbidity determination ensure tha
293. t sensor technology that has been developed for environmental monitoring of DO in water is considered an appropriate alternative to the amperometric method The luminescent sensor method involves the measurement of light emission characteristics of a luminescent based reaction at the sensor water interface see TECHNICAL NOTE While the relative benefits of the technology are apparent it should be recognized that its application at typical USGS sampling sites is relatively new therefore it does not benefit from the experience derived from years of use as is the case with the amperometric method e There are no consumables such as membranes or filling solu tions with the new method unlike the amperometric method e The technology does not consume oxygen at the sensor water interface therefore no stirring is required in slow or stagnant water e There are no known sources of interference to the method in natural aquatic systems Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 TECHNICAL NOTE The luminescent sensor employs a light emitting diode LED to provide incident light which excites the oxygen sensitive luminescent dye molecule substrate luminophore of the sensor After dissipation of the excitation energy longer wavelength light is emitted luminescence The magnitude of steady state luminescence intensity that is the average luminescent lifetime the phase difference between the excita
294. t techniques more accurately reflect the dynamic nature of particle movement within the water body Such differences are particularly pronounced when coarse silt or sand sized particles are present Also temperature changes in the sample during transport from source water to laboratory can cause differences between measurements taken on a static sample benchtop instrument and measurements taken under dynamic in situ or pumped conditions Some benchtop instruments do however provide flowthrough chambers that keep the sample in motion to approximate the dynamic conditions in the original water body As discussed previously instrument selection begins with a thorough consideration of study objectives and continues with questions about the use of the data the type of water body and its sources of turbidity and the way in which the data will be collected and stored A decision tree fig 6 7 2 is provided below to help guide the selection process In the decision process described below numbers 1 through 3 pertain to information in fig 6 7 2 numbers 4 and 5 provide additional guidance Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 14 TBY FNMU GLI Method 2 near infrared LED light source multiple beam ratiometric data correction wavelength 860 30nm Yes compensation Yes NTU EPA 180 1 or Std Meth 2130 B No White light tungsten filament color t
295. t the instrument to be used has been cleaned and calibrated properly and that the calibration process has been accurately documented section 6 7 2 gt Biased or erroneous readings can result from numerous factors including unmatched cell orientation colored sample solutions gas bubbles condensation and scratched or dirty sample cells see tables 6 7 1 and 6 7 2 Condensation on the sample cell commonly occurs when the water sample is much colder than the air temperature gt Turbidity measurement is time sensitive and therefore should be completed on site preferably in situ to avoid effects from a biodegradation growth settling or sorption of particulates in the sample or b precipitation of humic acids and minerals carbonates and hydroxides for example caused by changes in sample pH during transport and holding gt Iftemporary storage of samples is necessary collect samples in clean amber bottles keep out of sunlight and chill at or below 4 C to prevent biodegradation of solids or biological growth The holding time must not exceed 24 hours ASTM International 20032 Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 34 TBY Turbidities in surface waters can range widely even within the same water body depending on local hydrology sources of sediment or colored materials and disturbance regimes Although drinking water sources often have background turbidities of less than 1 turbidity u
296. table pump Use a positive displacement submersible pump and high density plas tic or fluorocarbon polymer sample tubing that is relatively gas impermeable if possible throughout measurement use equipment that avoids aeration and operate equipment to mitigate losses or gains of dissolved gases consult NFM 6 0 for proper downhole and flowthrough chamber sampling procedures Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 28 DO Dissolved Oxygen Version 2 1 6 2006 Downhole system Carefully lower a sampling tool attached to a wire line At the collection point in a well or in surface water break the scored tip of the ampoule using a sharp upward tug on the sampling tool This permits sample water to be drawn into the ampoule During transit to the surface progressively decreasing pressure in the ampoule prevents cross contamination from overlying water through the capillary tip Withdraw the ampoule from the sampler and mix the contents of the ampoule by inverting it several times allowing the bubble to travel from end to end Wipe all liquid from the exterior of the ampoule using a lint free tissue Overflow cell a b Purge the well NFM 4 2 Connect the plastic overflow sampler tube provided by CHEMetrics Inc to the outlet of the ground water pump tubing with a short length 2 inches or less of C flex tubing Reduce the pump flow rate to about 500 milliters mL
297. te for the instrument as described in tables 6 7 3 and 6 7 4 8 Surface water sites Repeat steps 5 7 for dynamic measurements Procedure at each vertical to be measured Determine the number of vertical locations refer to NFM 6 0 2 A and NFM 4 1 9 Before leaving the field clean the sonde sensor with a thorough rinse of deionized water and place it in the storage vessel Most instruments require a small amount of deionized water to be stored in the storage vessel with the sensors Follow the manufacturer s recommendations for storage of sondes sensors 10 Record data in the database in reporting units as described in table 6 7 4 using method codes specific to the instrument in use http water usgs gov owq turbidity codes xls accessed 9 30 2005 11 Ifturbidities are higher than the instrument range dilutions will be necessary Turbidity will need to be measured with static methods Take a representative sample and dilute it with one or more equal volumes of turbidity free water recording the volume of water used for dilution In such cases qualify the resulting data with a 4 in the Value Qualifier Code field in NWIS 12 Quality control Periodically check instrument performance by placing a primary or secondary calibration solution in the instrument storage vessel and comparing the standard value with the reading displayed Record in the instrument maintenance logbook all the readings obtained Turbidity
298. ted to the concentration determined from the titration Ifa saline solution is used to approximate the environmental water do not apply a salinity correction factor Chapter A6 Field Measurements Dissolved Oxygen Version 2 1 6 2006 30 DO 6 2 3 A EQUIPMENT AND SUPPLIES Equipment and supplies needed for the iodometric method are listed in table 6 2 5 The procedure involves the use of reagent packets avail able in premeasured pillow packets from commercial suppliers or pre pared as described in Skougstad and others 1979 and American Public Health Association 2005 Clean all equipment before use Table 6 2 5 Equipment and supplies for the iodometric Winkler method of dissolved oxygen determination mL milliliter V normal uS cm microsiemens per centimeter at 25 degrees Cel sius NFM National Field Manual for the Collection of Water Quality Data Beaker 2 000 mL glass or Bottles for biological oxygen demand BOD analysis glass stoppered 300 mL Stirrer magnetic Stirring bars Teflon coated Cylinder graduated 250 mL Flask Erlenmeyer 250 mL Buret 25 mL capacity with 0 05 mL graduations and Teflon stop cock Buret support stand Buret clamp double Alkaline iodide azide reagent Manganous sulfate reagent Sulfamic acid granules Sodium thiosulfate 0 025 N titrant Starch indicator solution Clippers for opening reagent pillows Appropriate safety gloves
299. tely used to achieve an accurate pH measurement For routine USGS water quality measurements ionic strengths ranging from 100 to 20 000 uS cm are considered standard When calibrating the pH electrode 1 Bring the pH buffers to the ambient temperature of the stream or ground water to be measured to the degree possible under the prevailing field conditions The temperature sensor liquid in glass or thermistor thermometer measurement vessel and electrode also should be at or near the ambient temperature of the environmental sample Maintain each buffer as close to sample temperature as possible when calibrating the electrode e Surface water and ground water When equilibrating the buffer temperature to ambient surface water temperature one method is to place the buffer bottles in a minnow bucket or mesh bag and suspend them in the body of surface water Alternatively place the buffers into a bucket or insulated cooler a containing surface water or b being filled with ground water When immersing buffer bottles in water ensure that the bottle is firmly capped and that the water level remains below the cap so that water cannot enter the bottle and contaminate the buffer 2 Inspect the pH electrode a Check for damage to the electrode bulb body or cables b Rinse any mineral precipitate off the electrode with DIW c Uncover unplug the fill hole d If you can visually see small bubbles within the electrode solution gen
300. the stabilized values on field forms e Ifthe readings do not meet the stability criterion after extend ing the measurement period record this difficulty in the field notes along with the fluctuation range and the median value of the last five or more readings 5 For EWI or EDI measurements proceed to the next station in the Cross section and repeat steps 3 and 4 Record on field forms the mean or median if appropriate value for each subsection mea sured 6 When the measurement is complete remove the sensor from the water rinse it with deionized water and store it 7 Record the stream conductivity on the field forms e Instill water median of three or more sequential values e EDI mean value of all subsections measured use the median if measuring one vertical at the centroid of flow e EWlI mean or median of all subsections measured see 6 0 Chapter A6 Field Measurements Specific Electrical Conductance Version 1 2 8 2005 14 SC Subsample measurement Representative samples are to be collected and split or composited according to approved USGS methods NFM 4 Measure the conduc tivity of samples as soon as possible after collection If the sample can not be analyzed immediately fill a bottle to the top close it tightly and maintain the sample at stream temperature until measurement Reported conductivity values normally are determined on an unfiltered sample Large concentrations of susp
301. til the CH5 gN4 is completely dissolved Filter through a 0 2 um filter into a clean flask 3 Quantitatively transfer the filtered hexamethylenetetramine into the flask containing hydrazine sulfate from step 1 Dilute solution to the 1 L mark with turbidity free water Stopper and mix for at least 5 minutes but no more than 10 minutes 4 Let stand for 24 hours at 25 1 C to develop the 4 000 turbidity unit suspension 5 Transfer the solution to an opaque light blocking polyethylene bottle and store refrigerated The 4 000 turbidity unit stock suspension is stable for about a year if stored at 20 to 25 C in amber polyethylene bottles To prepare 500 mL of a 400 turbidity unit calibrant solution dilute the 4 000 turbidity unit stock solution by a 1 10 ratio as follows 1 Mix 50 mL of the 4 000 turbidity unit stock solution in a 500 mL flask 2 Dilute to the mark with turbidity free water and mix 3 Transfer the solution to an opaque light blocking polyethylene bottle and store refrigerated The 400 turbidity unit stock solution is stable only for about one day Refer to ASTM International 2003a for detailed instructions Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 26 TBY To prepare a 40 turbidity unit calibrant solution dilute the 400 turbidity unit solution by a 1 10 ratio as follows 1 Mix 10 mL of the 400 turbidity unit stock solution in a 100 mL flask 2 Dilute to the
302. timating constituent loads Water Resources Research v 25 no 5 p 937 42 Edwards T K and Glysson D G 1988 Field methods for measurement of fluvial sediment U S Geological Survey Open File Report 86 531 118 p Fishman M J and Friedman L C eds 1989 Methods for determination of inorganic substances in water and fluvial sediments U S Geological Survey Techniques of Water Resources Investigations book 5 chap A1 703 p Helsel D R and Cohn T A 1988 Estimation of descriptive statistics for multiply censored water quality data Water Resources Research v 24 no 12 p 1997 2004 Horowitz A J Demas Fitzgerald T L Miller and Rickert 1994 U S Geological Survey protocol for the collection and processing of surface water samples for the subsequent determination of inorganic constituents in filtered water U S Geological Survey Open File Report 94 539 57 p Langland M J Blomquist J D Sprague L A and Edwards R E 1999 Trends and status of flow nutrients and sediment for selected nontidal sites in the Chesapeake Bay Watershed 1985 98 U S Geological Survey Open File Report 99 451 64 p Pettyjohn W A and Henning R 1979 Preliminary estimate of ground water recharge rates related streamflow and water quality in Ohio The Ohio State University Department of Geology and Mineralogy Completion Report No 522 323 p Sholar C J and E A Shreve 1998 Quality assurance p
303. tion light and the returned light is measured by the sensor and is inversely proportional to the DO concentration in the water 6 2 1 A EQUIPMENT AND SUPPLIES DO instruments meters and sensors are available from a number of commercial vendors Because the instructions for use calibration and maintenance often differ for each manufacturer the user is cautioned to read and carefully follow the instructional manual for the instrument system to be used DO instruments and expecially the sensors are sophisticated electronic equipment and require care in handling and operation The equipment and supplies required for the amperometric and luminescent sensor methods of measuring the DO concentration in a water body are listed in table 6 2 1 gt Amperometric instrument systems consist of the entire sensor assembly including the electrolyte solutions membranes and thermistor thermometers Protect sensors and other supplies from being jostled during transportation from sudden impacts sudden temperature changes and extremes of heat and cold gt Follow the manufacturer s recommendations for short term field and long term office storage of sensors and for performance checks Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 7 Table 6 2 1 Equipment and supplies for the amperometric and luminescent sensor methods of dissolved oxygen determination DO dissolved oxygen mg L milligram
304. tivity in most natural waters When the pH electrode is immersed in a solution for example a calibration buffer or a sample solution ions from the glass diffuse into a thin layer on the outside of the membrane while hydrogen ions diffuse through this layer until an equilibrium is reached between the internal and external ionic concentrations In this way an electrical potential is developed across the sensing surface which is proportional to the concentration of hydrogen ions in the surrounding solution pH meter info 2005 clean undamaged glass membrane is necessary for performing an accurate measurement of pH Chapter A6 Field Measurements pH Version 2 0 10 2008 8 pH Reference and measurement electrodes Contained within the pH sensor body are a reference electrode that generates a constant electrical potential and a pH measurement electrode The measurement electrode generates a separate electrical potential that is proportional to the concentration of hydrogen ions in the sample solution The electrodes together form a complete electrical circuit when the diffusion of hydrogen ions reaches equilibrium no electrical current is present and the difference in electrical potential that exists between the reference and the measurement electrodes is an indication of the hydrogen ion concentration in the solution The pH meter sensing this minute difference in electrical potentials converts this difference into a pH value b
305. tly tap the electrode body to dislodge them Bubbles trapped in the sensing tip of the electrode will affect the physical conditions necessary for correct operation of the electrode Do not wipe moisture from the electrode 3 Power up the pH meter The meter will perform an internal self test Note any discrepancies displayed by the meter and record these in the pH meter electrode logbook Malfunctioning meters usually require manufacturer attention do not try to fix malfunctioning meters in the field Having backup meters for field trips is necessary for this reason 4 Record in the ph meter instrument logbook the internal self test information displayed by the pH meter calibration log is mandatory for all calibrations pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 17 5 Initiate the calibration process by pushing the required calibration display sequences for the particular pH meter and electrode Standard USGS procedure for calibration of a single parameter pH meter and electrode system requires a two or three point calibration Some types of pH instrument systems may use a different multipoint calibration procedure in such cases follow the instructions provided in the instrument manual A single point calibration recommended by some manufacturers is not acceptable for USGS field measurement of pH 6 Record in the pH meter electrode logbook pH value measured temperature lot number and expirati
306. trodes is performed periodically field meters and calibration standards are removed from vehicles and brought indoors after use to avoid mechanical or electronic problems caused by extremes in temperature Batteries are changed and or units recharged regularly field instruments are calibrated prior to use as described in Section VI Calibration Procedures and Frequency If an instrument is not in good working order spare instruments are readily available so that there is no interference with field operations Instruments in need of repair are repaired in a timely manner 32 ASSESSMENT OF DATA VARIABILITY BIAS ACCURACY REPRESENTATIVE NESS AND COMPLETENESS Assessment of data variability and bias for the Virginia River Input Monitoring Program consists of collecting and analyzing duplicate and blank samples The purpose of these quality assurance practices is to quantify the variability of results from VDCLS the major laboratory that provides analyses for this study and to check for bias at VDCLS Between 5 and 10 percent of the samples collected at each monitoring site are collected as duplicate samples For each duplicate sampling two unmarked duplicate samples labeled five minutes apart will be collected from concurrent replicate samples and sent to VDCLS for the purpose of checking the analytical precision of the laboratory Field blanks analyzed by VDCLS are used to verify that clean sampling techniques are used by
307. trogen concentration and total Kjeldahl nitrogen concentration for VDCLS samples Total phosphorous is computed as the sum of particulate phosphorous and dissolved phosphorous 27 DATA REDUCTION VALIDATION AND REPORTING Samples are collected preserved and transported according to accepted SOP methods to DCLS Central Receiving by the USGS Central Receiving DCLS personnel log in samples and distribute them to the appropriate laboratory for analysis After analysis the data results are transformed into the correct concentration units keyed into the LIMS system Laboratory Information Management System by the chemist completing the analysis and reviewed by the appropriate laboratory personnel Upon approval the results are shipped back to VADEQ via FDT transfer and entered into the CEDS2000 database In the event data sheets are utilized to submit the samples to DCLS e g due to a CEDS WOM system failure the results are printed out onto laboratory sheets and given to the VADEQ Laboratory Liaison Results returned on paper are keyed into the CEDS2000 system by personnel in the Water Division and forwarded to the appropriate region or the Central office project manager Data go through a series of screens and reviews to identify invalid qualified or QA supported data by both DEQ and USGS personnel The qualified and QA supported data are then entered into the QWDATA water quality data base The USGS Virginia Water Science Center field
308. true ambient value Weather Service atmospheric read ings usually are adjusted to sea level and must be adjusted back to the elevation of the weather station Upon request a weather station may provide ambient atmospheric pressure Useacalibration checked pocket altimeter barometer to determine ambient atmospheric pressure to the nearest millimeter mm of mercury Check the accuracy of all field barometers before each field trip and record readings and adjustments in the log book If possible check barometer accuracy with information from an official weather station gt Use table 6 2 2 and figure 6 2 1 if the value used for atmospheric pressure has been adjusted to sea level gt correct weather station readings adjusted to sea level to ambient atmospheric pressure subtract appropriate values shown table 6 2 2 fig 6 2 1 from atmospheric readings adjusted to sea level shown in millimeters of mercury Although atmospheric pressure does not decrease linearly with increases in elevation linear interpolation is acceptable within the elevation ranges given in table 6 2 2 Alternatively plot the values from table 6 2 2 and extrapolate subtraction factors directly from the graph fig 6 2 1 Section 6 2 5 contains the table of oxygen solubility at various tempera tures and pressures Many instruments have the pressure temperature algorithm stored in internal memory Interactive tables also are available for us
309. ture can be of a substance subject to environmental regula tion and monitoring by State and local agencies with reference to a standard value This section describes methods for measuring temperature in air sur face water and ground water The methods are appropriate for fresh to saline waters Athermometer is any device used to measure temperature consisting of a temperature sensor and some type of calibrated scale or readout device Liquid in glass thermometers and thermistor thermometers are commonly used to measure air and water temperature The U S Geological Survey USGS uses the Centigrade or Celsius C scale for measuring temperature Some of the equipment and procedures recommended herein may not reflect the most recent technological advances in this case follow the manufacturer s instructions but comply with standard USGS quality control practices Chapter A6 Field Measurements Temperature Version 2 3 2006 4 T 6 1 1 EQUIPMENT AND SUPPLIES Thermometers and other temperature measurement equipment and supplies must be tested before each field trip and cleaned soon after use table 6 1 1 Each temperature instrument must have a log book in which all calibrations and repairs are recorded along with the man ufacturer make and model and serial or property number Table 6 1 1 Fquipment and supplies used for measuring temperature minus plus C degrees Celsius
310. ue or use more strin gent accuracy criteria that reflect the data quality objectives of the study For accurate calibration be sure that the water is 100 percent saturated with oxygen step 4 above Dissolved Oxygen Version 2 1 6 2006 U S Geological Survey TWRI Book 9 DO 17 Procedure 3 Air calibration chamber in water This calibration method is applicable only to amperometric instruments An air calibration chamber permits calibration of the DO sensor at the temperature of the water in which the DO concentra tion is to be measured This calibration procedure minimizes errors caused by temperature differences Air calibration chambers for in water calibrations currently are not available on the open market and one of the most common the YSI 5075A calibration chamber is no longer manufactured For most multi parameter water quality instru ments the manufacturer provided ground water flow cell may be modified and used as an air calibration chamber in water The modifi cation requires the cell to be mounted on the sonde with one port of the cell plugged and the other port vented to the atmosphere with tubing 1 Insert the sensor probe into the rings of the DO wand dip this calibration chamber into the surface or ground water to be mea sured allowing the temperature readings to stabilize Remove the wand and pour out the excess water leaving a few drops e Check for and remove any water droplets on the sen
311. uent Concentrations that appear to be outliers are reexamined using the field notes to determine the presence of any unusual circumstances or hydrologic conditions If there is no indication of anything out of the ordinary the laboratory is asked to review their records for accuracy If necessary data are corrected and changes are documented with the rationale and source of changes made 22 B Completeness of Sampling A complete data set is needed to meet the objectives of the project In particular the suites of analyses must be comprehensive and the sampling coverage must capture the variability of both base flow and high flow instantaneous loadings of the constituents Completeness is documented by 1 Periodic checks by the project water quality data base manager which assess the completeness and accuracy of calculations for the analyses 2 Assessment of the number of samples collected versus the number of samples received An ongoing list is kept to make sure that all analyses are received from VDCLS Periodically this list is sent to VDCLS and VDEQ for their information and use 3 Development of as complete and representative a data set as possible covering all streamflow conditions 4 Collection of field and quality assurance data on a scheduled basis with documentation of each sample as shown in Appendix 1 C Representativeness The collection of water quality samples representative of river conditions is essential Sam
312. uinox and rinse well with tap and DI APPENDIX 5 Quality Assurance Project Plan Enhanced sediment collection for improving continu ous sediment simulations December 2005 QUALITY ASSURANCE PROJECT PLAN Enhanced Sediment Collection for Improving Continuous Sediment Simulations Prepared By Douglas L Moyer Kenneth E Hyer US Geological Survey Virginia Water Science Center 1730 E Parham Road Richmond VA 23228 December 2005 TABLE OF CONTENTS Introduction and Project Description Objectives Project Organization and Responsibility Study Design Continuous Water Quality Monitoring Protocols Discrete Water quality Sampling Protocols Data Analysis and Measures of Success Schedule References List of Tables 1 Project Organization and Responsibility 2 Project Schedule based on USGS Fiscal Years List of Figures 1 Correlation of turbidity and suspended sediment on the James River Page Introduction and Project Description Elevated suspended sediment levels are causing an adverse impact on the living resources and associated aquatic habitat of streams rivers and estuaries These elevated suspended sediment levels may impair the growth of aquatic vegetation through reduced light levels bury filter feeding organisms reduce the habitat available for macroinvertebrates and contribute to decreased fish populations These elevated sediment levels also may be playing an important role in the transport of particle associ
313. uments according to information provided in figure 6 7 2 and table 6 7 3 2 Obtain a discrete sample For drinking water samples proceed to step 3 For non drinking water samples skip to step 4 3 For drinking water samples dilution is required to comply with USEPA regulations a Dilute the sample with one or more equal volumes of turbidity free water until turbidity is less than 40 turbidity units after mixing and degassing b Record the volume of turbidity free water used for dilution Follow steps 1 5 from the previous section for samples with turbidity less than 40 turbidity units c Skip to step 5 below 4 For non drinking water samples where USEPA compliance is not required with 100 and 1 000 turbidity unit ranges only place a cell riser if available into the cell holder before inserting the sample cell This decreases the length of the light path in order to improve the linearity of measurements Do not use the cell riser for the lower turbidity ranges a For turbidimeters with adjustable ranges and signal processing capabilities for instance ratio mode to compensate for high particle densities select the desired configuration table 6 7 3 and operate according to manufacturer s recommendations Some instruments will automatically switch to different modes for example ratio mode or to a different light source Record instrument mode on field sheets b Select the desired range on the t
314. urbidimeter Turbidity Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 39 Dilutions can introduce errors if coarse material is present or if the sample matrix changes with the addition of diluant When making dilutions perform at least three at approximately 80 50 and 20 percent of the original concentration Record the turbidity of each dilution and determine if they are linear and correlate positively with the percentage diluted If the response is nonlinear alternative instrument designs that better compensate for interferences should be considered Do not forget to adjust the turbidity value of diluted samples using the dilution factor 5 Fill the cell with sample water a Hold the cell by the rim top lip not beneath the lip b Gently agitate the sample 25 times Without hesitation carefully but rapidly pour sample water into the cell to the fill mark c Wipe the exterior of the cell using a soft lint free cloth or tissue to remove moisture condensation from cell walls d Ifnecessary apply a thin layer of silicon oil table 6 7 1 onto the exterior of the cell to reduce condensation on the cell and mask slight scratches and nicks e Ifrapid particle settling is occurring steadily invert the cell 25 times taking care not to shake too vigorously which could entrain gases in the sample Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 40 TBY 6 Record the sampl
315. uring sample transit and storage see section 6 7 3 The following are examples of tests that can be performed periodically for quality control of some sources of variability in turbidity determinations Static determination Measurement variability For one cuvette with sample and gently agitate to keep particulates in suspension Measure the turbidity and remove the cuvette from the turbidimeter Repeat at least three times using the same cuvette Record each reading and determine the standard deviation of the measurements Consider submitting replicate samples for laboratory analysis These procedures may not adequately characterize measurement variability that is caused by particle settling Chapter A6 Field Measurements Turbidity Version 2 1 9 2005 48 TBY Subsampling variability For one water sample agitate the sample then withdraw an aliquot into the cuvette measure turbidity discard the sample and clean the cuvette Repeat at least three times Record each reading and determine the standard deviation of the measurements Operator variability Split one water sample into two or more subsamples using a churn splitter Have different operators prepare cuvettes and measure turbidity on the subsamples Consider submitting samples for laboratory analysis Sampling variability Collect at least two independent samples from the source using standard techniques Prepare turbidity cuvettes for each sam
316. use clean an LCD lens use only plastic approved lens cleaners do not use alcohol acetone or other harsh chemicals as these will fog the lens gt Store thermometers securely when not in use Keep thermometers in a clean protective case when not in use Each thermometer sensor and the case must be free of sand and debris Keep thermometers dry and in a protective case during tran sit Store liquid filled thermometers with the bulb down Store thermometers in a cool place and inside a building when not in use do not leave a thermometer in a vehicle that could change in temperature to very hot or very cold result ing in thermal shock to the thermometer Check the batteries of thermistor type thermometers for proper voltage before using Record the calibration data in the log book for each ther mometer liquid in glass thermistor thermometer or ther mistor containing field measurement instrument Note if a thermometer has been serviced or replaced Temperature Version 2 3 2006 U S Geological Survey TWRI Book 9 CALIBRATION 6 1 2 Thermometer calibration differs from the process by which a pH or conductivity sensor is adjusted until the accuracy of its performance conforms to that of an accepted calibration standard For temperature measurements calibration refers to a comparison or accuracy check at specified temperatures against a thermometer that is certified by the Natio
317. ving water correct pH instrument system functioning will be inhibited gt The determination of pH in situ using a multiparameter instrument system is described in NFM 6 0 and 6 8 The system selected depends on the data quality objectives of the study and on site specific conditions Before collecting the sample and making ex situ measurements it is advisable to determine the range of pH values in the cross section or estimate the magnitude of lateral mixing of the waterway at the field site using an in situ measurement method for example with a multiparameter sonde pH Version 2 0 10 2008 U S Geological Survey TWRI Book 9 pH 23 When making an ex situ pH measurement Set up the pH instrument system close to the sampling site in order to minimize the time lapse between sample collection and pH measurement 1 The glass membrane of the electrode should not contact the sides or bottom of the beaker or other measurement vessel Use only a clean measurement vessel 2 Fill the measurement vessel with sufficient sample to ensure that the electrode reference junction is fully immersed taking care not to aerate the sample 3 After calibration or measuring the pH of a different sample rinse the electrode and thermistor three times with DIW This crucial step must always be completed between differing solutions 4 Rinse the electrode and thermistor sensors two times with the sample as follows a First rinse Pour an a
318. vironment Federation p 4 136 to 4 137 http www standardmethods org ASTM International 2006 D888 05 standard test methods for dissolved oxygen in water accessed May 17 2006 at http www astm org cgi bin SoftCart exe DATABASE CART REDLINE PA GES D888 htm L mystore zmtx 1699 ASTM International 2005 D5543 94 2005 standard test methods for low level dissolved oxygen in water accessed May 15 2006 at http www astm org cgi bin SoftCart exe DATABASE CART REDLINE_PA GES D5543 htm L mystore aaam0310 Brown Eugene Skougstad M W and Fishman M J 1970 Methods for collection and analysis of water samples for dissolved minerals and gases U S Geological Survey Techniques of Water Resources Investigations book 5 chap Al p 126 129 CHEMetrics Inc 2006 Oxygen dissolved accessed May 15 2006 from http www chemetrics com catalogpdfs html Gilbert T W Behymer T D Castaneda H B March 1982 Determination of dissolved oxygen in natural and wastewaters American Laboratory p 119 134 Hach Company Hach LDO technology real world FAQ accessed September 27 2005 at http www hach com hc view document only invoker View HTML_LDO_R EALWORLD_FAQ NewLinkLabel Hach LDO Technology Real World FAQ PREVIOUS_BREADCRUMB_ID HC_SEARCH_KEYWORD SESSIONID ATBwTUIURXIOemMwTmpVek9UazJNe VpuZFdWemRFVI dXQT09QQ Hem J D 1985 Study and interpretation of the chemical characteristics of natural water 3d ed U S Geologic
319. waters is usually too low to be expressed as milligrams per liter micrograms per liter or moles per liter in contrast to most other chemical species Hem 1989 gt pHisreported on a scale that most commonly is shown to range from 0 to 14 see TECHNICAL NOTE below The pH scale is related directly to and hydroxide concentrations at a given temperature A solution is defined as having a neutral pH pH 7 00 at 25 C when the H concentration is equal to the concentration solution is defined as acidic if the activity concentration is greater than that of the OH ion pH is less than 7 at 25 solution is defined as basic or alkaline when the concentration is greater than the H concentration pH is greater than 7 at 25 C The majority of natural freshwater systems for which water quality data are routinely collected by the USGS are considered to be dilute that is the volume of dissolved solids is less than 50 milligrams per liter and the ionic strength of the solution the strength of the electrostatic field caused by the ions is less than 107 For dilute solutions activity values can be assumed to be equal to measured ion concentrations Hem 1989 Therefore throughout the text of this section the terms activity and concentration as they relate to the hydrogen ion are used interchangeably Chapter A6 Field Measurements pH Version 2 0 10 2008 pH 3 4
320. y Version 2 1 9 2005 4 TBY Although technological advances in turbidity measurement have produced a variety of instrument types to meet one or more of these differing objectives turbidity instruments of different designs commonly do not yield identical or equivalent results Moreover the mixing of different source waters or dilutions of environmental samples may not produce linear results when measuring for turbidity because of the variety of factors that contribute to and can have an effect on turbidity Selection of the appropriate turbidity instrument requires therefore consideration of project objectives data requirements and the physical and chemical properties of the water body This section on turbidity provides protocols and guidelines for selecting appropriate field and laboratory instruments and procedures for instrument calibration and maintenance turbidity measurement data storage and quality assurance that meet stated objectives for U S Geological Survey USGS data collection efforts The use of consistent procedures and instruments within and among projects or programs for which turbidity data will be compared over space and time is crucial for the the success of the data collection program Select instruments carefully after reviewing project objectives and after consulting with cooperating agencies Report turbidity on the basis of the individual instrument design Use identically prepared calibrati
321. y Version 2 1 9 2005 U S Geological Survey TWRI Book 9 TBY 17 Once a particular instrument design and set of reporting units table 6 7 4 have been selected the user evaluates the literature and cost information from instrument manufacturers to decide on the most appropriate model Although rapid changes in optical and sensor technology preclude the inclusion of specific manufacturers models in figure 6 7 2 the turbidity parameter and methods codes spreadsheet http water usgs gov owq turbidity codes xls accessed 9 30 2005 provides a partial list of available models according to instrument design and reporting units which can be used in combination with figure 6 7 2 to narrow the options for the choice of an instrument to meet a specific set of study objectives Figure 6 7 2 shows that differences among instrument designs have resulted in a wide array of options for measuring turbidity Although these options provide flexibility and the capability to tailor the data collection program to the needs of each particular study they also present problems for data comparison among studies with differing objectives or water sources particularly if different equipment is used in the studies When data are to be compared among different programs or studies sending duplicate samples to a laboratory such as the National Water Quality Laboratory NWQL provides a reference for quality assurance purposes and is recommended the NWQL for exa
322. y the manufacturer Take care not to scratch the electrode tip Clogged or partially clogged junction Follow the manufacturer s instructions to unclog the junction Water is cold or of low ionic strength Allow more time for equilibration consider using a different electrode section 6 4 3 B Sluggish response to pH changes pH measurement is biased negatively Refer to table 6 For gel filled electrodes Dirty bulb Rinse bulb carefully with DIW If organic inorganic biological residue persists consult the manufacturer s recommendations Visibly clogged junction Follow the manufacturer s instructions to unclog the junction Water is cold or of low ionic strength Allow more time for equilibration consider using a different electrode section 6 4 3 B Erratic readings Loose or defective connections Tighten clean or replace connections Broken or defective cable Repair or replace cable Static charge Polish face of meter with antistatic solution Loose battery connection Tighten Air bubbles in the electrode bulb Shake electrode gently Too much pressure in flowthrough chamber Release and reduce pressure Weak batteries Replace with new fully charged batteries Chapter A6 Field Measurements pH Version 2 0 10 2008 28 pH 6 4 6 REPORTING Due to the rapidity of pH reactions in environmental samples the effect of temperature on the operation of the pH instrum
323. zed and approved Data Analysis and Measures of Success Multiple linear regression analyses will be used to develop statistically significant regressions between continuously measured turbidity and suspended sediment concentrations Success will be measured through paired evaluations of the estimated sediment loadings to the Bay with based on turbidity sediment regressions and without the enhanced data collection ESTIMATOR approach These data comparisons are expected to improve sediment loading estimates for the Bay Additionally this demonstration project should encourage the application of this technology at other existing RIM stations and other basins throughout the non tidal portions of the Bay Watershed Lastly the project will provide refined estimates of suspended sediment loads and concentrations that can be used in existing and future sediment transport models Schedule Table 2 Project schedule based on USGS Fiscal Years FY06 FY07 FY08 Months Months Months S Project planning meetings with stakeholders application for necessary permits Order and install instrumentation and equipment plans Collect turbidity data and storm samples Develop initial turbidity sediment regression equations Verify turbidity sediment regression equations through continued data collection Compare sediment loads turbi

QUALITY ASSURANCE PROJECT PLAN for the Virginia River Input

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