Home

Environmental Protection Agency

Contents

1. Site Characteristics _ Estimate the distance from the ground water concentration contour interval for each COC to buildings under investigation _ Estimate the distance from vadose zone source area to buildings under investigation _ Describe the surface cover between the vapor source and buildings under investigation Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 61 of 104 APPENDIX D Standard Operating Procedures SOPs for Sample Collection NOTE the following SOPs are specific to the Ohio EPA Division of Emergency and Remedial Response They are provided as a reference only and are not meant to dictate an exclusive method for soil gas sampling Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 62 of 104 SOP 2 5 1 Procedures for Active Soil Gas Collection Using Direct Push 1 0 Systems Scope and Application 1 1 1 2 1 3 Vapor intrusion is defined as vapor phase migration of VOCs into occupied buildings from underlying contaminated ground water and or soil Soil gas surveys provide information on the soil atmosphere in the vadose zone that can aid in assessing the presence composition source and distribution of contaminants The purpose of this document is to provide guidance for conducting soil gas sampling
2. Although not quantitative passive soil gas sampling methods can be a useful tool for 1 collecting soil gas from low permeability and high moisture settings where conventional active soil gas sampling may be problematic 2 detecting compounds present at very low concentrations 3 assessing preferential vapor migration pathways such as utility corridors and foundation cracks to determine if these pathways are acting as significant VOC migration pathways into a structure For additional information on passive sampling techniques see ITRC guidance January 2007 Appendix D page D 16 7 2 Emission Flux Chamber Method Flux chambers are enclosures that are placed directly on a surface for a few hours to a few days and the resulting contaminant concentration in the enclosure is then measured which yields the contaminant flux at a surface Flux chambers are a qualitative tool that can be used to locate surface fluxes of VOC contamination and entry points into structures Flux chambers may be suitable for structures with dirt floors larger slabs in good condition and for future use scenarios on undeveloped land Specialized equipment and experienced staff is necessary when conducting flux chamber evaluations For additional information see ITRC guidance January 2007 Appendix D page D 24 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 28
3. Oh Environmental l O Protection Agency Division of Emergency and Remedial Response SAMPLE COLLECTION AND EVALUATION OF VAPOR INTRUSION TO INDOOR AIR FOR REMEDIAL RESPONSE AND VOLUNTARY ACTION PROGRAMS Guidance Document Indoor Air Vadose Zone Soil Gas Soil Contamination residual or mobile NAPL Ted Strickland Governor Lee Fisher Lt Governor Chris Korleski Director Ohio EPA Acknowledgements This guidance was developed by a workgroup representing Ohio EPA staff from the Division of Emergency and Remedial Response DERR and the Division of Air Pollution Control DAPC and environmental consultants most of whom are Certified Professionals CPs for Ohio EPA s Voluntary Action Program VAP Workgroup members include Ohio EPA Environmental Consultants Gavin Armstrong Mark Butler Brownfield Restoration Group Paul Koval John Garvey Partners Environmental Diane McClure Jeff Hullinger Carnoustie Consulting Chuck Mellon Barb Knecht HZW Environmental Nita Nordstrom Matt Knecht HZW Environmental Chris Osborne Bill Lozier Environmental Resources Management Carrie Rasik Karl Reinbold Audrey Rush Lisa Shook Martin Smith Vanessa Steigerwald Dick Brian Tucker Jeff Wander Randy Watterworth The following document was developed using established guidance from U S EPA the Interstate Technology Resource Council ITRC American Society of Testing and Materials ASTM and other states modif
4. EPA OSWER 2002 For VOCs that do not have an associated MCL ground water concentrations must meet target risk and hazard levels for the vapor intrusion pathway and must be adjusted for the presence of multiple chemicals Use of BUSTR Petroleum Standards for Voluntary Actions At VAP sites a volunteer may use BUSTR action levels including action levels for soil and groundwater to indoor air contained in look up tables found in OAC 1301 7 9 13 J 3 as the generic numerical standards for petroleum at residential commercial and industrial properties in the VAP For more information on applying BUSTR action levels as VAP applicable generic standards please see Applying Generic Petroleum Standards under the VAP Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 47 of 104 Determining Applicable Risk Goals and the Need for Further Evaluation Comparison of results to applicable risk goals and whether further evaluation is needed depends upon which program the site clean up follows For VAP properties a multiple chemical adjustment is necessary and the resultant risk ratio for the vapor intrusion pathway is carried through as a vapor intrusion contribution to site wide risk Please note the VAP does not use screening values to determine pathway completeness or to eliminate COCs from further vapor intrusion risk assessment For RRP properties sc
5. Hewitt A D 1994 Losses of Trichloroethylene From Soil During Sample Collection Storage and Laboratory Handling U S Army Corps of Engineers Cold Regions Research and Engineering Laboratory Special Report 94 8 Hewitt A D 1999 Storage and Preservation of Soil Samples for Volatile Compound Analysis U S Army Corps of Engineers Cold Regions Research and Engineering Laboratory Special Report 99 5 Interstate Technology Regulatory Council Diffusion Sampler Team February 2004 Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in Groundwater Interstate Technology Regulatory Council Brownfields Team December 2003 Vapor Intrusion Issues at Brownfield Sites The Interstate Technology amp Regulatory Council Vapor Intrusion Team January 2007 Vapor Intrusion Pathway A Practical Guide Johnson P C May 2002 Identification of Critical Parameters for the Johnson and Ettinger 1991 Vapor Intrusion Model American Petroleum Institute Technical Report Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 52 of 104 Liikala T L K B Olsen S S Teel and D C Logan 1996 Volatile Organic Compounds Comparison of Two Sample Collection and Preservation Methods Environmental Science and Technology v 30 n 12 p 3441 3447 Massachusetts
6. Male Connector 1 Outer hole Swagelok SS 400 7 4 Female adapter Anchoring cement 1 4 Swagelok nut Modeling clay or teflon washer SLAB 1 4 OD Stainless steel tubing 3 8 Diameter inner or pilot hole SUB SLAB MATERIAL Figure 4 Example of a Sub slab Soil Gas Probe When possible permanent sampling points should be used so that repeated sampling can be conducted to evaluate seasonal or temporal variations Multiple sample locations should be chosen and multiple sampling events should be conducted Samples should be collected with a bias towards worst case conditions e areas or times of expected highest concentrations 4 8 Sampling Crawl Spaces Air within a crawl space without a slab can be sampled similarly to indoor air For evaluating the human health risk associated with crawl space air an attenuation factor of 1 0 should be used for crawl spaces consistent with U S EPA guidance 2002 Thus the indoor air quality is assumed to be equal to the crawl space air quality for evaluation purposes Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 21 of 104 5 0 LEAK TESTING Atmospheric air drawn into the soil gas probe can result in diluted soil gas samples that do not represent soil gas concentrations for the COC To ensure that valid soil gas samples are collected as part of a vapor intrusion assessment a tr
7. ND Non Detect NM Not measured Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 98 of 104 APPENDIX F Ohio Environmental Protection Agency Division of Emergency and Remedial Response Indoor Air Sub Slab Sampling Form OHIO EPA DERR Site Site Name Address Occupant Information Name Address Telephone No H Number and Age of Occupant s Does anyone smoke inside the building Building Characteristics Type of building circle Residential Industrial School Commercial Multi use Other If residential what type circle Single family Condo Multi family Other If commercial what is the business How many floors does the building have Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 99 of 104 Does the building have a circle Basement Crawl space Slab on grade Other Is the basement used as a living work space area What type of foundation does the building have circle Field stone Poured concrete Concrete block Other Describe the heating system and type of fuel used Is there an attached garage Spill Contaminant Source Information Type of petroleum VOC release When did the release occur What areas of the building have been impacted by the release Are
8. Procedures 7 1 Probe Assembly and Installation 7 1 1 7 1 2 Drill a diameter pilot hole approximately 2 inches in depth Figure 1 in the attached schematic drawings Using the pilot hole as your center drill a 1 diameter outer hole to a depth of approximately 1 Vacuum any cuttings out of the hole Figure 2 Continue drilling the inner or pilot hole through the slab and a few inches into the subslab material Figure 3 While drilling carefully vacuum out any cuttings from the outer hole Note if area highly contaminated with volatiles volatiles may be drawn into the building use caution Determine the length of stainless steel tubing required to reach from the bottom of the outer hole through the slab and into the open cavity below the slab To avoid obstruction of the probe tube ensure that it does not contact the subslab material Using a tube cutter cut the tubing to the desired length Attach a measured length typically 3 4 of 1 4 OD stainless tubing to the female connector SS 400 7 4 with the Swagelok nut Make sure that the tubing rests firmly in the fitting body and that the nut is finger tight While holding the fitting body firmly tighten the nut 11 turns Insert the 14 hex socket plug into the female connector If using a stainless steel socket plug wrap one layer of Teflon thread tape around the threads to prevent binding If using a brass socket plug no T
9. must be measured or estimated at no less than three 3 locations in that soil layer Depending on the volume of soil being evaluated additional locations may be warranted If taking the minimum required samples the value of the soil input parameter used in the J amp E model must be the site specific value which results in the most conservative estimate of risk The selected value should fall within the practical range of values for that parameter as shown in Tables 7 and 10 of the J amp E model User s Guide for Evaluating Subsurface Vapor Intrusion into Buildings Users Guide If the selected value does not fall within this range the modeler should provide sufficient justification for the use of the selected value To use a Statistical representation such as a mean value of site specific soil input parameter s in lieu of default values in a given soil layer the input parameter s must be measured or calculated at no less than eight 8 locations excluding any outliers in that soil layer Depending on the volume of soil being evaluated additional locations may be warranted If taking sufficient samples to perform a valid statistical evaluation of the data the value of the soil input parameter used in the J amp E model for a soil layer may be a site specific value which is considered representative of the soil layer Again the selected value should fall within the practical range of values for that parameter as shown in the User s Guide
10. opening doors windows can influence indoor air results Additionally indoor air values can be influenced by concentrations of VOCs in ambient outdoor air that are unrelated to releases in soil or ground water For these reasons outdoor ambient air and subslab soil gas should also be collected when sampling indoor air 4 0 ACTIVE SOIL GAS SAMPLING PROCEDURES 4 1 Overview The following section provides basic guidelines for conducting soil gas sampling for assessing the vapor intrusion pathway Appendix D contains Ohio EPA s standard operating procedures for advancing soil gas probes subslab or using direct push techniques for collection of exterior soil gas Soil gas sampling can be used for a number of purposes including initial site characterization delineation of ground water plume influence identification of source areas and potential receptors remediation and post remediation monitoring and for developing and refining a CSM Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 9 of 104 4 2 Designing a Soil Gas Sampling Plan A soil gas sampling plan should be site specific and a function of the DQOs Ohio EPA DERR recommends using the conceptual site model checklist for vapor intrusion included in Appendix C to assist in developing a soil gas sampling strategy General considerations should include the following e Identify the objecti
11. A rough sketch of the area is drawn where the ports are installed with the major areas noted on the sketch 8 2 A global positioning system GPS unit may be used to document coordinates outside of a structure as a reference point 8 3 Equipment used for the installation of sampling ports should be cleaned by heating inspected and tested prior to deployment Health amp Safety When working with potentially hazardous materials follow site specific health and safety procedures All site activities should be documented in the site specific Health and Safety Plan HASP Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 81 of 104 CONSTRUCTION AND INSTALLATION OF PERMANENT SUB SLAB SOIL GAS WELLS S EEES E E E E FIGURE 1 INNER or PILOT HOLE 3 8 DIAMETER INNER or PILOT HOLE SLAB 4 L Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 82 of 104 CONSTRUCTION AND INSTALLATION OF PERMANENT SUB SLAB SOIL GAS WELLS FIGURE 2 OUTER HOLE 1 DIAMETER OUTER HOLE 13 8 2 3 8 DIAMETER INNER or PILOT HOLE SLAB i Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 83 of 104 CONSTRUCTION AND INSTALLATION OF PERMANE
12. Action Programs Page 70 of 104 5 0 5 1 Sample Collection Methods Four common methods of sample collection for COCs are discussed in this SOP Two of the methods use Tedlar bags as sample containers while the third method uses evacuated canisters and the last method adsorbents DQOs for the project should determine which sample collection method is used The Lung Box Sampler Bag Samplers The Lung Box allows direct filling of a Tedlar air sample bag using negative pressure without passing gas through the pump This eliminates the risk of contaminating the pump or the sample The Lung Box pictured below includes an in line pump Other types of bag samplers may require the use of a separate air pump or hand pump f N y Asy ace ery N N Bus ey r SAA Semi permanent soil gas probe location with multi depth implants The blue bag sampler is used to collect soil gas samples using 1 liter Tedlar bags Note that each tube is labeled with the sampling depth the PVC pipe is used to protect the soil gas tubing Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 71 of 104 5 1 1 1 5 1 1 2 5 1 1 3 5 1 1 4 Prior to sampling and after an appropriate equilibrium period ambient air needs to be removed from the sample train by purging Purging of the filter pack is required if sampling occurs within 24 hours of inst
13. CONTROLLER CANISTER VALVE Figure 5 Schematic of Summa Canister Note When requesting Summa Canisters from a lab it is recommended that you request canisters that are dedicated to indoor air sampling Request canisters that are certified clean to appropriate levels for indoor air screening The analytical method must be able to identify and quantify the target VOCs and be capable of meeting acceptable indoor air risk levels Ohio EPA DERR recommends that laboratory analysis for VOCs be done using gas chromatography mass spectrometry GC MS and where appropriate using the high resolution selected ion monitoring SIM mode for low level detection All indoor air sample results submitted to Ohio EPA DERR should be reported in units of ppbv and or yg m along with the original laboratory reports Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 27 of 104 7 0 OTHER SAMPLING METHODS 7 1 Passive Soil Gas Soil gas can be qualitatively assessed by passive sampling with an adsorbent material are placed in the subsurface and left for a period of time The sampling devices are then retrieved and analyzed Passive soil gas sampling can be an effective tool in understanding the composition and the location of subsurface vapor plumes Ohio EPA DERR does not recommend using passive soil gas samples for quantifying contaminant concentrations in soil gas
14. Department of Environmental Protection December 1995 Guidelines for the Design Installation and Operation of Sub slab Depressurization Systems Northeast Regional Office Massachusetts Department of Environmental Protection MADEP April 2002 Indoor Air Sampling and Evaluation Guide Office of Research and Standards McAlary T A P Nicholson H Groenevelt and D Bertrand 2009 A Case Study of Soil Gas Sampling in Silt and Clay Rich Low Permeability Soils Ground Water Monitoring amp Remediation v 29 n 1 p 144 153 New Hampshire Department of Environmental Services July 2006 Vapor Intrusion Guidance New Jersey Department of Environmental Protect NJDEP August 2005 Field Sampling Procedures Manual New York State Department of Health 1997 2003 Study of Volatile Organic Chemicals in Air of Fuel Oil Heated Homes revised November 14 2005 Nicholson P D Bertrand and T McClary 2007 Soil Gas Sampling in Low Permeability Soils In Proceedings Air and Waste Management Association s Vaport Intrusion Learning for the Challenges Providence RI P 299 310 September 26 28 2007 Ohio Department of Commerce Bureau of Underground Storage Tank Regulations Ohio Administrative Code 1301 7 9 13 Petroleum UST Corrective Action Ohio EPA Division of Drinking and Ground Waters Various Dates Technical Guidance Manual for Hydrogeologic Investigations and Ground Water Monitoring O
15. Dichlorodiphenyldichloroethene DDE Dichloroethane 1 1 Dichloroethane 1 2 Dichloroethene 1 1 Dichloroethene cis 1 2 Dichloroethene trans 1 2 Dichloropropane 1 2 Dichloropropene 1 3 Dieldrin Endosulfan Epichlorohydrin Ethyl Ether Ethylacetate Ethylbenzene Ethylene oxide Ethylmethacrylate Fluorene Furan Heptachlor Hexachloro 1 3 Butadiene Hexachlorobenzene Hexachlorocyclopentadiene Hexachloroethane Hexane n Hydrogen cyanide Hydrogen sulfide Isobutyl Alcohol lsobutanol Isopropyloenzene Cumene Lindane Mercury Methacrylonitrile Methoxychlor Methyl acetate Methyl acrylate Methyl bromide bromomethane Methyl butyl ketone Methyl chloride chloromethane Methyl Ethyl Ketone MEK CAS Number 123 73 9 132 64 9 124 48 1 95 50 1 106 46 7 na 75 71 8 72 55 9 75 34 3 107 06 2 75 35 4 156 59 2 156 60 5 78 87 5 542 75 6 60 57 1 115 29 7 106 89 8 60 29 7 141 78 6 100 41 4 75 21 8 97 63 2 86 73 7 110 00 9 76 44 8 87 68 3 118 74 1 77 47 4 67 72 1 110 54 3 74 90 8 7783064 78 83 1 98 82 8 58 89 9 7439 97 6 126 98 7 72 43 5 79 20 9 96 33 3 74 83 9 591 78 6 74 87 3 78 93 3 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 57 of 104 Chemical CAS Number Methyl Isobutyl Ketone MIBK 108 10 1 Methyl tert Butyl Ether MTBE 1634 04 4 Methylcyclohexane 108 8
16. If the selected value does not fall within this range the modeler should provide sufficient justification for the use of the selected value Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 44 of 104 11 6 Determining Site Specific Soil Vapor Permeability Value in the J amp E Model Soil vapor permeability Kv is one of the most sensitive parameters in the J amp E model Typically the model estimates Kv using either the default soil type or site specific soil input values However a user defined Kv may be input into the model in lieu of the model calculated value To permit the user to define Kv the Ohio EPA recommends direct measurement of this value using laboratory testing procedures Although the J amp E model User s Guide for Evaluating Subsurface Vapor Intrusion into Buildings Users Guide provides a method for the user to estimate Kv by indirect methods only a direct measurement of this should be used in lieu of the model calculated value The American Society for Testing and Materials ASTM Designation D 6539 00 entitled Standard Test Method for Measurement of Pneumatic Permeability of Partially Saturated Porous Materials by Flowing Air provides a method for laboratory determination of the coefficient of permeability for air flow pneumatic permeability through partially saturated porous materials Laboratory testing of undistu
17. Installation of Permanent Subslab Soil Gas Ports 1 0 2 0 3 0 Scope and Application This standard operating procedure SOP outlines the procedure used for the construction and installation of permanent subslab soil gas ports The ports are used to sample gas beneath the floor slab of dwellings and other structures Method Summary Using an electric hammer drill or rotary hammer an inner or pilot hole is drilled into the concrete slab to a depth of approximately 2 with the diameter drill bit Using the pilot hole as the center an outer hole is drilled to an approximate depth of 1 using the 1 diameter drill bit The 1 diameter drill bit is then replaced with the diameter drill bit The pilot hole is then drilled through the slab and several inches into the subslab material Once drilling is completed a stainless steel probe is assembled and inserted into the pre drilled hole The probe is mounted as flush as possible with the surrounding slab so it will not interfere with pedestrian or vehicular traffic and cemented into place A length of Teflon tubing is attached to the probe assembly and to a sample container or system Sample Preservation Containers Handling and Storage 3 1 SUMMA Canister Sampling After the subslab soil gas sample is collected the canister valve is closed an identification tag is attached to the canister and the canister is transported to a laboratory under chain of custody for analy
18. Installation of Soil Gas Implants For long term soil gas monitoring applications multiple sampling events from the same location or when using evacuated canisters a stainless steel aluminum plastic or ceramic implant can be installed at any depth by direct push Implants are inserted down inside the probe rods when the appropriate sampling depth has been achieved Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 67 of 104 4 2 1 4 2 2 4 2 3 4 2 4 4 2 5 4 2 6 Drive probe rods to the desired depth using the implant point holder and an implant anchor point or expendable drive point If using steel implants that attach screw in to the drive point DO NOT disengage the drive point when depth of interest has been reached If using implants which do not need to be attached to the drive point the drive point may be disengaged using the point popper Pull the tool string back approximately 1 2 to push the expendable point out with the point popper Attach appropriate sample tubing Teflon nylon or PEEK Depending on implant type and diameter of sample tubing Tygon tubing of appropriate size may be used to securely connect the implant to the sample tubing If sample tubing is pre cut allow it to be approximately 48 inches longer than required depth of the implant e g if the sampling depth is at 6 5 feet then tubing s
19. Programs Page 15 of 104 For undeveloped sites soil gas samples should be collected to assess vapor intrusion for potential receptors as appropriate The number and depth of soil gas samples should be based on the CSM to evaluate concentrations in soil gas and the attenuation of soil gas as it migrates to the surface Note that once a building is constructed vapors may accumulate below the foundation and reassessment of the vapor pathway may be warranted depending on the site specific situation Soil Gas Probes Soil gas samples are collected from the vadose zone and analyzed at a fixed laboratory or using an on site mobile laboratory Temporary soil gas probes are only sampled once and all equipment is removed upon sample completion Permanent soil gas probes are sampled over time to evaluate seasonal or other variations in concentrations Whether installing a temporary or permanent soil gas probe it is necessary to prevent ambient air from diluting the soil gas sample A leak test should be performed to verify the integrity of the vapor probe seal Section 5 0 Figure 2 shows several types of soil gas probes and well material Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 16 of 104 Schedule 40 Schedule 80 1 8 PVC well screen Retractable PVC wrapped and unwrapped soil gas probe Expendable Permanent Passively placed probe drive points so
20. Vapor Intrusion Considerations for Redevelopment Solid Waste and Emergency Response EPA 542 R 08 001 March 2008 and 3 Interstate Technology Regulatory Council ITRC Technical and Regulatory Guidance Vapor Intrusion Pathway A Practical Guide January 2007 Remediation of Environmental Media The media source of vapor intrusion can be addressed through application of a soil or ground water remedy Remediation of soil and ground water contamination may include source removal technologies to reduce contaminant concentrations in soils and soil gas such as soil vapor extraction or technologies to reduce concentrations in ground water such as in situ bioremediation or pump and treat In general source removal and soil vapor extraction remedies are likely to reduce or eliminate soil gas migration and thus may prevent the need for institutional or building control remedies Institutional Controls Institutional controls are activity and use limitations that are recorded with the deed record Examples of institutional controls include restricting a property to commercial or industrial uses only prohibitions of inhabitable structures in areas where vapor intrusion risk goals are exceeded or building specific conditions such as prohibition of basements Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 49 of 104 Building Control Remedies Buil
21. and shall pertain to active soil gas surveys whereby a volume of soil gas is pumped out of the vadose zone into a sample collection device for analysis Detection of individual constituents by active soil gas sampling is limited by the physical and chemical properties of individual contaminants of concern and the soil characteristics of the site In general chemical parameters or criteria to be considered prior to selecting soil gas sampling activities are as follows Vapor Pressure gt 0 1 mm Hg Henry s Law Constant gt 0 1 Degree of soil saturation chemical and or water lt 80 Sampling zone is permeable and permits vapor migration Please refer to Appendix A Chemicals of Concern for Vapor Intrusion in the Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA S Remedial Response and Voluntary Action Programs for a complete list of the volatile chemicals which can be detected using soil gas sampling techniques Results from soil gas surveys are used in both qualitative and quantitative evaluations The quality and application of the data is dependent upon many factors including but not limited to the DQO s used to develop the sampling plan the number of sample locations and data points the selection of the sample locations the soil characteristics of the site the distribution of the contaminants in both the vadose and saturated zones the equipment and personnel used to gather th
22. bottom of soil interval for highest detected concentration in IA Thickness of soil Site specific For all site specific soil parameters Soil vapor Default value Values generated by the model for soil empirical data used permeability Sand type may be used must be co located with areas containing COCs If using site specific Soil characteristics for additional soil soil type based i P Default Value ee at site specific Soil Type strata can only be used with site specific Sand analyses default geotechnical data values from J amp E can be used Bulk density Euan See comment for Soil Type Sand Total Porosity Default values Sand See comment for Soil Type Soil water Default values filled porosity Sand See comment for Soil Type Fraction organic rd values See comment for Soil Type content Enclosed floor space 10 cm No other value accepted thickness aoil Biag 40 g cm s No other value accepted pressure Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 38 of 104 Table 4 Acceptable J amp E Model Inputs for Bulk Soil Variable Default Value Comments Restrictions differential Enclosed Larger value may floor space 1000 cm J amp E default require deed length restriction Larger value may 1000 cm J amp E de
23. geotechnical engineering and environmental field in Ohio where the Unified Soil Classification System USCS is routinely employed For the J amp E model the US SCS must be used 100 Percent Sand Figure 6 U S Soil Conservation Service Classification Chart Showing Centroid Compositions Solid Circles Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 43 of 104 In addition to visual examination laboratory testing is required to determine a representative grain size distribution in each layer for which soil values other than default values will be used Atterberg limit determinations may also be used to assist in soil classification Ohio EPA recommends no less than three sieve analyses grain size distribution determination to classify each soil layer Depending on the variability observed when logging samples additional sieve analyses may be needed To justify the use of site specific soil input parameters soil bulk density total porosity water filled porosity and fraction organic carbon sufficient vertical and lateral characterization of the migration media must be performed The user should note that the fraction organic carbon is not an input parameter in either ground water or soil gas model To use site specific soil input parameter s in lieu of default values in a given soil layer the input parameter s
24. mitigative controls are contemplated early in the evaluation process a limited number of well locations and sampling events may suffice However risk goals should not be considered met for ground water plumes without sufficient sampling to determine ground water fate and transport The intent of establishing contaminant trends within monitoring wells for vapor intrusion from ground water is two fold First the degree of natural temporal variability of the VOC contamination must be established so that an appropriate contaminant input concentration can be used for modeling purposes Second the stability of the VOC plume must be demonstrated so that the risk to receptors would not be expected to increase due to contaminant migration and or degradation SOIL Soil matrix data are needed to define the location of the VOC source extent of soil contamination and to assess the risk from direct contact with soils However soil matrix data are less than ideal for evaluating vapor intrusion risk because of the uncertainty associated with using partitioning equations and the potential loss of VOCs during sample collection Human health risk calculated from soil matrix samples may be biased low due to inherent VOC escape during sample collection Hewitt 1994 Hewitt 1999 Liikala et al 1996 Vitale et al 1999 These factors should be carefully considered when evaluating the vapor intrusion exposure pathway with soil matrix samples Loss of VOCs dur
25. of 104 8 0 7 3 Indoor Subslab Differential Pressure Measurements Measurement of the pressure gradient between the subslab and overlying structure can assist in interpreting the direction of vapor transport whether into or out of the structure If the building is over pressured relative to the subslab measured indoor concentrations might be more likely attributed to above ground sources from within the building Conversely if the building is under pressured relative to the subslab measured indoor concentrations might be more likely attributed to below ground sources associated with vapor intrusion The success of this approach may require multiple indoor air measurements to establish long term patterns GROUND WATER Ideally soil gas sampling should be conducted in conjunction with ground water monitoring However ground water data alone sometimes can be used to model potential vapor intrusion For technical guidance on installing and sampling ground water monitoring wells please see the Ohio EPA Division of Drinking and Ground Waters Technical Guidance Manual Some special considerations for constructing ground water monitoring wells for the purposes of assessing the vapor intrusion pathway include Screen Placement Contaminants volatilize from the top of the water table Hence monitoring wells used to make vapor intrusion evaluations should be screened across the air water interface meaning the well screens should not be su
26. of fresh air entering the building In the J amp E model these parameters are calculated from user inputs and can be found in the INTERCALC sheet of the model The range in values for the ratio of Qsoi Qg comes from a search of the radon and contaminant transport literature where both sub slab and indoor air concentrations were reported Johnson 2002 Therefore J amp E model results having a Qsoi Qg ratio less than 0 0001 should be considered suspect 11 2 Bulk Soil There are large uncertainties associated with measuring concentrations of VOCs during soil sampling preservation and chemical analysis as well as the uncertainties associated with soil partitioning calculations However allowing evaluation of bulk soil without requiring additional soil gas collection is useful for sites where VOCs are not risk drivers and relatively low concentrations in soil are encountered Allowing bulk soil data is particularly useful at VAP sites where applicable standards must be developed for all COC s and all media When bulk soil results from J amp E modeling do not exceed 1 E 06 cancer risk goal and 0 1 hazard quotient for VOCs further evaluation soil for vapor intrusion is not necessary Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 36 of 104 Table 4 summarizes the acceptable J amp E model input parameters for use with bulk soil data Sand is the
27. reduced dead air volume that must be purged is reduced and decontamination problems are reduced as the sample does not contact the rod bore 4 1 1 Clean all parts prior to use Inspect all probe rods and clear them of obstructions Install O rings on the PRT expendable point holder and the PRT adapter Test fit the adapter with the PRT fitting on the expendable point holder to assure that the threads are compatible and fit together smoothly PRT fittings are left hand threaded and must be rotated counter clockwise to engage the point holder threads Push the PRT adapter into the end of the selected tubing Tape may be used on the outside of the adapter and tubing to prevent the tubing from spinning freely around the adapter during connection especially when using Teflon tubing REMEMBER The sample will not come into contact with the outside of the tubing or adapter Attach the PRT expendable point holder with O ring to the female end of the leading probe rod Attach an O ring to an expendable drive point and insert into the expendable point holder Attach the drive cap to the male end of the drive rod and position rod under probe Drive the PRT rod configuration into the ground connecting probe rods as necessary to reach the desired depth Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 66 of 104 4 2 4 1 10 4 1
28. step can include the use of screening tools and values models risk assessment or refined data collection to determine if the pathway is complete and of possible concern 10 1 Use of Screening Levels The use of screening levels for vapor intrusion evaluation is program specific Screening levels listed in U S EPA OSWER Vapor Intrusion Guidance November 2002 are available for ground water soil gas and indoor air For soil see Section 11 2 For both VAP and RRP sites exceedance of a screening level can serve as a trigger for more refined data collection and evaluation or indicate the need for a remedial action U S EPA lists screening levels for COCs at the target range of 1E 04 to 1E 06 risk levels The values listed represent the lower value of either the noted excess lifetime cancer risk ELCR goal or noncancer endpoint represented by the hazard quotient equal to 1 HQ 1 For sites in the RRP or VAP the cumulative cancer risk goal is 1E 05 and noncancer endpoint is the hazard index HI of 1 Screening levels are listed for ground water deep soil gas gt 5 feet bgs shallow soil gas a k a subslab or lt 5 feet bgs and indoor air The indoor air value was calculated using intake exposure factors for a residential exposure and chemical specific toxicity factors The remaining values soil gas and ground water were derived through the use of attenuation factors developed by U S EPA Sample Collection and Evaluation of Vapo
29. the components in reverse order of the above assembly instructions Return all components to the original shipping containers and package them as received Verify that all parts are packed for return by referencing the packing slip 11 Review and complete the field sampling log form Complete the appropriate Chain of Custody record as supplied to you by the lab and return the sample to the laboratory for analysis Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 95 of 104 INLET FILTER ON FLOW CONTROLLER FLOW CONTROLLER 1 4 SWAGELOK FITTING TO SUMMA CANISTER 1 4 SWAGELOK FITTING Sa FRONT VIEW OF GAUGE ON FLOW CONTROLLER CANISTER VALVE Schematic of Summa Canister Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 96 of 104 Attachment 2 For DERR SOP 2 5 3 CANISTER SAMPLING DATA SHEET OPERATOR print GENERAL INFORMATION Site Location Site Address Canister EPA ID City Grab Sample Regulator SN County Ambient Sub Slab i gt n LONG Other specify tNorthingt tEastingt Sampling Information Sample Setup Date Time initial canister vacuum Sampler Calibrated Date mmidd yy Time mititary Hg or mm Hg Flaw rate comin Sampler Start Time Date Time Fin
30. then detach the bag from the tubing Complete the Sample Data Sheet with all applicable information Evacuated Canister 5 3 1 Follow the procedures described in Ohio EPA DERR SOP 2 5 3 Collection of Samples on Adsorbents 5 4 1 An alternative approach to collecting soil gas in a sample container is to concentrate the soil gas on an adsorbent This type of method is required for SVOCs and is often used for mercury generally compounds heavier than naphthalene Typically a pump is used to draw soil gas through the Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 73 of 104 adsorbents and the adsorbent is then analyzed by a laboratory A variety of adsorbent cartridges and pumping systems are available from commercial vendors In addition it is essential that the soil gas be drawn through the adsorbent by the pump not pumped through the adsorbent to eliminate the chance for cross contamination by the pump It is often recommended that two tubes be used in series to avoid breakthrough losses in areas of suspected higher concentrations The adsorbent purge rate and sample volume must be determined by discussion with the analytical laboratory Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 74 of 104 SOP 2 5 2 Construction and
31. there any information you feel is important related to this site and the samples collected which would facilitate an accurate interpretation of the indoor air quality Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 103 of 104 APPENDIX G Comparison of Tubing Type to Vapor Absorption Researcher Ouellette pa Nicholson Hartman 2004 sige et al 2007 2008 Tubing 2006 LDPE mainea womens Nat Seton TCE pentane compounds a Tygon a ar N A N A Acceptable for butane and KE pentane Sorption of Sorption of Nylaflow Acceptable naphthalene aromatic Acceptable for and 1 2 4 TCB hydrocarbons TCE Teflon Acceptable Acceptable N A Acceptable for TCE Sorption of Vinyl frends N A N A N A pentane PEEK N A Acceptable N A Acceptable for TCE Sorption of TCE N A not analyzed Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 104 of 104
32. time the sample train should be tested for leaks A minimum equilibrium time should be established to prior to sampling the implant While a 24 hour equilibrium period will ensure adequate equilibration three to four hours is generally sufficient After equilibration the implant is ready for sampling Refer to Section 5 0 for sampling procedures using the bag sampler e g Lung Box or vacuum canister e g Summa or Silco To provide long term security to the sampling port the installation of a riser pipe protector with cap can be installed and finished with a concrete pad If desired less secure finishing of a sampling port can be completed using 2 4 ID PVC pipe sections with associated caps Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 69 of 104 aam a amag ANN SS SS fi ik Fay SE RS Example of a Soil Gas Implant Ground surface elevation Flush mount or above ground protective casing if specified Cap or valve w depth of probe indicated Concrete cement if specified Coarse sand pea gravel drainage layer Bentonite granules Drilled hole Implant tubing 1 8 1 4 Teflon Nylaflow or PEEK Hydrated bentonite Sand pack Vapor implant Figure not to scale Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary
33. volume should be consistent for all samples collected from the study area When purging or collecting samples using a vacuum pump or a canister the vacuum applied to the soil gas probe should not exceed ten inches of mercury or 100 inches water and the flow rate generally should not exceed 200 milliliters per minute This should limit the potential for ambient air being drawn into the sample from the ground surface and it should limit desorbing of vapors from contaminated soils although research has shown that flow rate does not appear to be an important variable on soil gas concentrations for relatively coarse grained soils To maintain sample integrity e Maximum holding times for soil gas samples should not be exceeded Contact laboratory for holding times and to ensure using best collection method e Soil gas samples should not be chilled during storage unless specified by the method e Keep all gas samples out of direct sunlight e Complete maintain all sampling records e g chain of custody sample data forms etc Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 11 of 104 The appropriate sample method is dependent on the DQOs developed for the project Coordinate with the laboratory to ensure that sufficient volume is collected Soil gas samples should be analyzed for the appropriate COC including breakdown products as part of the
34. with on site multi where oxygen is expected to be present gas meter at ambient levels Qualitative Because minor leakage of a quantitative leak test chemical compound such as helium 10 or less of the total concentration of the tracer compound in the shroud around the probe seal should not affect data quality the presence of low concentrations of helium in the sample is not a major cause for concern If elevated levels of helium the leak test chemical greater than 10 in the shroud are observed in a sample the soil gas data should not be considered reliable and the probe seal should be modified to reduce the infiltration of ambient air and re sampled Portable tracer gas specific field monitoring devices with detection limits in the low part per million ppm range should be adequate for screening samples for tracer leak testing In order to ensure minimal or no leakage in the sampling train a shut in test can be conducted In this test a vacuum of 100 inches of water is applied to the closed off sampling train and potential leaks are verified with an in line vacuum gauge see McAlary et al 2009 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 23 of 104 6 0 INDOOR AIR SAMPLING 6 1 General Approach Indoor air sampling can be conducted when soil ground water and or soil gas including subslab soil gas data indicate the potent
35. 10 or as specified in the site specific Quality Assurance Project Plan QAPP The outdoor ambient sample must be collected at approximately the same time and for the same time interval as the indoor air samples The following general Quality Assurance QA procedures apply 8 1 A rough sketch of the area is drawn where the samples are collected with the major areas noted on the sketch 8 2 A global positioning system GPS unit may be used to document coordinates outside of a structure as a reference point 8 3 Proper completion of associated data sheets log books and COC is vital to the overall success of the sampling effort 8 4 Photographs showing proper function of the flow regulators at the start and end of the sample time period are recommended Additional photos of the surrounding area where the samplers are placed are also recommended Health amp Safety When working with potentially hazardous materials follow site specific health and safety procedures All site activities should be documented in the site specific Health and Safety Plan HASP Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 93 of 104 Attachment 1 for DERR SOP 2 5 3 Sampling Instructions for Canisters With Pneumatic Flow Controllers Inspect your canister shipment once received from the lab and or equipment provider Compare contents with the packing sl
36. 11 After desired depth has been achieved disengage the expendable drive point Using the inner rods insert the expendable point popper to the bottom of the rod string and then slowly pull up on the probe rods using the rod grip pull system Retract the rods approximately 4 6 up to create a void from which to sample the soil gas Position the probe unit to allow room to work around the sample location Insert the PRT adapter end of the tubing down the inside diameter of the probe rods Feed the tubing down the rod bore until it hits bottom on the expendable point holder Allow approximately 4 6 ft of tubing to extend out of the hole before cutting it Grasp the excess tubing end and apply some downward pressure while turning it in a counter clockwise motion to engage the adapter threads with the expendable point holder Continue turning until the PRT adapter O ring bottoms out in the expendable point holder Pull up lightly on the tubing to test the engagement of the threads Failure of the PRT adapter to thread could mean that intrusion of soil may have occurred during driving of the rods or disengagement of the expendable drive point At this time the sample train should be tested for leaks Sampling the location can commence following an equilibrium period minimum of 15 minutes Connect the sampling tubing and follow appropriate purging and sampling procedures Refer to Section 5 1 for sampling procedures using the bag sampler
37. 12 4 6 Exterior Soll Ga Segor cide anita nue dasa gine een ei ata rea 14 4 7 Subslab Soil Gas Sampling ccccceccceceeeeeeeeeeeeeeeeceeeeeceaeeeeaaeeeeeeeceaeeesaaeeeeaaeseeeeessaeeseaeeeeeeeeaes 19 4 8 Sampling Crawl Spaces 0 ccccceescecceeeeceeeeeeeaeseeaeeceeeeeceaeeeeeaeeceaeeeseaesseaaeseeeeeseeeesaeeeeaaessaeeesaes 21 BO EEA TES TING aE ET E EE E Dae a eg atc A each aeheacag aetabay 22 6 0 INDOOR AIR SAMPLING cccseccsseeeeeseeeseeeeeneeeeeeesesaeeenseeeeeaeeesaaesaneaeeneeeeseaaesaaneeeeeeeeseeseseaesnneeeneeees 24 6 1 General Approach cccceccceceteceeseeceeeeeceeeeeeeeaeseeaaecaeeecaaeeseaaessaaeesaeeecsaesseaaesseaeesceessaesseaeessinees 24 6 2 Site Inspection Product Inventory and Field Screening ccecceceeeeeeeeeeeeeeeseeeeeseeeeeeeeeeeaees 25 6 3 Sample Collection and Analysis cccccceecceseeeeeeneeeeeeeeeeeaeeeeaaeseeeeesaeeesaaesseeeeeseaeeesaeseeneesnnees 25 7 0 OTHER SAMPLING METHODS 2 ccc sins centicectiecedeteessdeeectecedencecusevsesncagdeceesettetestevdencuecnderesstvesesureuteues 28 7 4 Passive SOG AS zanu ete Ae a a es a LR 28 7 2 Emission Flux Chamber Method cc cccececceeeeeceeeeeceeeeceaeeeeaeeseeeeeseaeeesaaeeseeeescaeeesaeeeeneessaees 28 7 3 Indoor Subslab Differential Pressure Measurement ccccceeecececeeeeeeeeeeeneeceeeeeseaeeeseneeenaees 29 8 0 GROUND WATER iaiia ea e aaea aeaa aaa aaa aeaea ae Teia aa S daera aeeai E aieia aaia 29 CROESO
38. 7 2 Methylene bromide 74 95 3 Methylene chloride 75 09 2 Methylmethacrylate 80 62 6 Monochlorobiphenyl PCB na m Xylene 108 38 3 Naphthalene 91 20 3 n butyl benzene 104 51 8 Nitrobenzene 98 95 3 N Nitroso di n butylamine 924 16 3 n propyl benzene 103 65 1 o Nitrotoluene 88 72 2 o Xylene 95 47 6 Polychlorinated Biphenyls 1336 36 3 p Xylene 106 42 3 Pyrene 129 00 0 Sec butyl benzene 135 98 8 Styrene 100 42 5 Tert butyl benzene 98 06 6 Tetrachloroethane 1 1 1 2 630 20 6 Tetrachloroethane 1 1 2 2 79 34 5 Tetrachloroethene 127 18 4 Toluene 108 88 3 Trichloroethane 1 1 1 71 55 6 Trichloroethane 1 1 2 79 00 5 Trichloroethene 79 01 6 Trichlorofluoromethane 75 69 4 Trichloropropane 1 2 3 96 18 4 Trimethylbenzene 1 2 4 95 63 6 Trimethylbenzene 1 3 5 108 67 8 Vinyl Acetate 108 05 4 Vinyl Chloride 75 01 4 Xylenes Total 1330 20 7 i Not all releases of PCBs need to be evaluated for vapor intrusion Please see Section 3 3 for further information Note The appropriate analytical method should be chosen based on discussions with the laboratory Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 58 of 104 APPENDIX B Special Considerations for Evaluating Residential Properties Evaluating the vapor intrusion pathway using the prescribed step wise approach listed in Figure 1 is preferred when volatilization to indoor air is pote
39. AS Number 1 1 2 Trichloro 1 2 2 trifluoroethane 76 13 1 1 2 4 Trichlorobenzene 120 82 1 1 2 Dibromo 3 chloropropane 96 12 8 1 2 Dibromoethane ethylene dibromide 106 93 4 1 3 Dichlorobenzene 541 73 1 1 Chlorobutane 109 69 3 2 Chloro 1 3 butadiene chloroprene 126 99 8 2 Chlorophenol 95 57 8 2 Chloropropane 75 29 6 2 Methylnaphthalene 91 57 6 2 Nitropropane 79 46 9 Acenaphthene 83 32 9 Acetaldehyde 75 07 0 Acetone 67 64 1 Acetonitrile 75 05 8 Acetophenone 98 86 2 Acrolein Propenal 107 02 8 Acrylonitrile 107 13 1 Aldrin 309 00 2 alpha HCH alpha BHC 319 84 6 Benzaldehyde 100 52 7 Benzene 71 43 2 Benzo b fluoranthene 205 99 2 Benzylchloride 100 44 7 beta Chloronaphthalene 91 58 7 Biphenyl 92 52 4 Bis 2 chloroethyl ether 111 44 4 Bis 2 chloroisopropyl ether 108 60 1 Bis 2 chloromethyl ether 542 88 1 Bromodichloromethane 75 27 4 Bromoform 75 25 2 Butadiene 1 3 106 99 0 Carbon Disulfide 75 15 0 Carbon Tetrachloride 56 23 5 Chlordane 57 74 9 Chlorobenzene 108 90 7 Chlorodibromomethane 124 48 1 Chlorodifluoromethane 75 45 6 Chloroethane ethyl chloride 75 00 3 Chloroform 67 66 3 Chrysene 218 01 9 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 56 of 104 Chemical Crotonaldehyde 2 butenal Dibenzofuran Dibromochloromethane Dichlorobenzene 1 2 0 Dichlorobenzene 1 4 p Dichlorobipheny PCB Dichlorodifluoromethane
40. COC concentrations at various levels within a building may assist in determining the vapor source 6 2 Site Inspection Product Inventory and Field Screening Prior to indoor air sampling an inventory of all potential volatile sources present must be evaluated to determine the presence of indoor sources see Appendix F for the Indoor Air Sampling Form When field screening a building for indoor vapor sources a field instrument capable of detecting vapors in the part per billion range ppbv should be used To minimize the impact of cross contamination from indoor air sources during residential or commercial sampling indoor activities such as smoking use of sprays solvents paints etc should be suspended a minimum of 24 48 hours prior to and during sampling Outdoor activities that could influence indoor air levels such as mowing painting and asphalting should also be suspended during sampling For additional information see ITRC 2007 Section 1 6 1 Background Air Concentrations An evaluation of potential preferential pathways into the structure should also be done The evaluation should identify any foundation penetrations such as water sewer gas electric telecommunication lines or sumps as well as foundation integrity e g cracks dirt floors 6 3 Sample Collection and Analysis When collecting indoor air samples it is preferable to collect samples at a time and location that will result in the highest potential concentra
41. DUCTION fiiaocccccccdeccscscacesacccteacecdvacessscdeccecdeauedey sted dageedteaaes siceuscuadsouddectucts suadsanuscetacvesscnvenicectuaerd 1 2 0 SCOP E EP P A cb teats bet cect E a OEE 2 3 0 VAPOR INTRUSION EVALUATION OVERVIEW ccccseccsseceesseeeeseeeeeeeeeseaeseseeeenseaeesseeeseesaeeeeeeesneeas 3 3 1 Vapor Intrusion ASSCSSMEMNM cceceeeeeneeeeeeene eee E AAA AEE EEA E ENE ERER 3 3 2 Conceptual Site MOdel o oo eee cecceececeeeeeceeeeeeeeeaaeeeeneeceeeeeeeaeeseaaeseeecaeeesaaeseeeeeseneeeseaaeseaaeeseneeees 5 3 3 Data Quality Objective Process cccceececeeseeeeeseeseeeeecaeeeeaaeeeeaeeceaeeeseaeeesaaeseeeeeseaeeesaeeseeeeeenees 7 3 4 Sampling Strategy niiin iani ana ni rna a ded ennai daaa aandaa 8 4 0 ACTIVE SOIL GAS SAMPLING PROCEDURES cccseeccesseeeseeeeeeeeeeeeeescaeseseeenseeeeseeseseeeenseeeeeenenss 9 4 1 ONEI EE eases eds cky anes es Sate Ao tents heer eda erh tee Daan a aveed eth wae 9 4 2 Designing a Soil Gas Sampling Plan cccccceesseeeeeeeceeeeeeeaeeeeeeeceeeeeseaeeeeaaesecaeeesaeeesaeseeeeeeaas 10 4 3 Preferential Pathway Survey c cccccceeeececeeeeeeaeeeeeeeeeaeeecaaeeeeaaeseeeeeeeaaeeeeaaeseeeeeseaeeesaeeseaeeeeaes 10 4 4 Sample Collection and Analysis c ccceccceceeeeeeseeceeeeeecaeeeeeaeeeeeeeseeeesaaeeeeaaeeseeeescaeeseaeseseeeeaes 11 4 5 Analytical Detection Limits 0 ccccceeccceeeeee cece eeeeeeceeeeceaeeeeaaeeeeeeeseaeeesaaeeeeaaeeseaeeesaeeseaeseneeeeaes
42. Engineering Issue Indoor Air Vapor Intrusion Mitigation Approaches Office of Research and Development EPA 600 R 08 115 U S EPA January 2009 Risk Assessment Guidance for Superfund Volume Human Health Evaluation Manual Part F Supplemental Guidance for Inhalation Risk Assessment Office of Solid Waste and Emergency Response EPA 540 R 070 002 Final U S EPA Standard Operating Procedure SOP for Installation of Subslab Vapor Probes and Sampling Using EPA Method TO 15 to Support Vapor Intrusion Investigations Draft Dominic DiGiulio Ph D Office of Research and Development National Risk Management Research Laboratory Ground Water and Ecosystem Restoration Division Ada Oklahoma undated U S EPA 2009 Region 3 Regional Screening Levels Users Guide December 2009 Vitale R J R Forman and L Dupes 1999 Comparison of VOC Results Between Methods 5030 and 5035 on a Large Multi State Hydrocarbon Investigation Environmental Testing and Analysis January 1999 p 18 39 Wisconsin Department of Health and Family Services Division of Public Health February 13 2002 Chemical Vapor Intrusion and Residential Indoor Air Guidance for Environmental Consultants and Contractors Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 55 of 104 APPENDIX A Chemicals of Concern for Vapor Intrusion Chemical C
43. Mee epee E E A E A T E E RSE eon PEE 30 10 0 DATA EVALUATION caai ccc cccscesesecoecincrcaseceecctessecttecsacs stands cuacsvedeesseaeesececeucdesduadecnanteduadesdaesterduexdeddiae 30 10 1 Use of Screening Levels c ccc ceeececeeeeeeeeeeeesaeeeeeeeecaeeeeaaeseeaeeceaeeeceaeeseaaesgeeeeseeeeesaaeseeaeeseneeees 31 19 2 Data Analysis cii aos eiii eA ee ee EEE AE A a a ee ee 33 10 3 Identified Areas and Exposure Units ccccccseeeeeceeeeeeeeeeeeeeeneeeeeeeeseaeeesaaesseaeeseeeeesaeeeseaeeseeetees 34 11 0 MODELING THE VAPOR INTRUSION PATHWAY ccccccecsssseeesseeeeeeeeeeeeseseaeenseeeeseaesaseaesnseeeeeseneas 33 11 1 Overview of the Johnson and Ettinger MOdel cccecceceeeeeeeeeeeee cee eeeeaeeeeeeeseneeesaeeeeeeeeeeeeess 34 V2 BUIK Soila nodoetan a tae eee 35 11 3 Soil Gas and Ground Watter ccececeesceeeeeeeeeeaeeeeeeeceeeeeceaeeesaaeeseeeesaaeeesaaesseaeeseeeesaeeeseaeeenaeeee 37 11 4 Acceptable J amp E Model Input Parameters cccccececeeeceeeeeeneeceeeeeceaeeeeeaeseeneeeseaeeesaeeneaeeseeeeess 42 11 5 Use of Site Specific Soil Type and Input Parameters in the J amp E Model ccceeeeeeeeeeeeeees 42 11 6 Determining Site Specific Soil Vapor Permeability Value in the J amp E Model c eeeeeeeees 45 12 0 EVALUATION OF IMMINENT HAZARD IN AN EXISTING BUILDING csseeeeeseeeseeeseseeeeeseeeees 46 13 0 RISK CHARACTERIZATION cscccceceseeeeeeeeeeeeeeeescaesesneeeneeeeeaes
44. NT SUB SLAB SOIL GAS WELLS pa a a FIGURE 3 COMPLETED HOLE PRIOR to PROBE INSTALLATION 1 DIAMETER OUTER HOLE 13 8 SLAB 3 8 DIAMETER INNER or PILOT HOLE SUB SLAB MATERIAL Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 84 of 104 CONSTRUCTION AND INSTALLATION OF PERMANENT SUB SLAB SOIL GAS WELLS TAAS oa a pS a FIGURE 4 SOIL GAS PROBE INSTALLED SWAGELOK SS 400 7 4 1 4 FLUSH MOUNT HEX SOCKET PLUG FEMALE CONNECTOR 1 DIAMETER OUTER HOLE ANCHORING CEMENT 1 4 SWAGELOK NUT MODELING CLAY OR TEFLON WASHER E 1 4 OD STAINLESS STEEL TUBING SUB SLAB MATERIAL K 3 8 DIAMETER INNER or PILOT HOLE Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 85 of 104 CONSTRUCTION AND INSTALLATION OF PERMANENT SUB SLAB SOIL GAS WELLS FIGURE 5 na 1 4 OD TEFLON TUBING SOIL GAS PROBE PREPARED FOR SAMPLING SWAGELOK SS 400 7 4 FEMALE ADAPTER SWAGELOK SS 400 1 4 MALE CONNECTOR 1 DIAMETER OUTER HOLE 13 8 ANCHORING CEMENT U4 SWAGELOK NUT MODELING CLAY OR TEFLON WASHER SLAB lt H 1 4 OD STAINLESS STEEL TUBING ese lt 3 8 DIAMETER INNER or PILOT HOLE SUB SLAB MATERIAL Sample Colle
45. a is preferred for decision making Most risk decisions and the need for mitigation are not made through indoor air sampling results alone Vapor Intrusion Assessment The steps in Figure 1 apply at sites whether or not there are buildings currently present and or occupied at a site Current buildings and future anticipated building scenarios as appropriate will determine sampling strategy and data evaluation While the assessment process is presented in a step wise fashion the vapor intrusion pathway may be evaluated in an iterative manner Flowchart Step 1 Conduct a Site assessment Property Assessment Identification of potential releases of hazardous substances and or petroleum to environmental media at the site A comprehensive evaluation of the current and historical operations at a site should be conducted Compilation of complete site information is essential for identifying all potential exposure pathways For VAP properties a complete Site assessment must be conducted in accordance with the Ohio Administrative Code OAC 3745 300 06 RRP sites may use ASTM E1527 05 or most recent version Standard Practice for Environmental Site Assessments Site assessment Environmental Site Assessment Process For simplicity this guidance will not repeat the requirements necessary to conduct a Site assessment However developing a CSM is a necessary component of this guidance See the discussion in Step 3 for more details on CSM compone
46. acer compound can be used to check for surface annular seal leaks Depending on the nature of the contaminants of concern a number of different compounds can be used as a tracer as shown in Table 2 Sulfur hexafluoride SFe and helium are commonly used as tracers because they are readily available have low toxicity and can be monitored with portable measurement devices lIsopropanol the main ingredient in rubbing alcohol can also be used as a tracer but requires laboratory analysis for the tracer In all cases the same tracer should be used for all sampling probes at any given site The leak test should be conducted using a tracer that is not expected to be present in the soil gas being tested When choosing a liquid tracer check with the laboratory to determine the reporting limit for the proposed tracer Ideally the reporting limit for the tracer should be similar to the constituents present in the soil gas Potential short circuiting of atmospheric air during sampling can also be indirectly evaluated through measurement of oxygen and carbon dioxide data collected from soil gas probes not for subslab soil gas sampling For example if oxygen concentrations at a probe installed within a petroleum hydrocarbon source area are at atmospheric levels the soil gas data should not be considered reliable and the probe seal should be modified and the probe re sampled Ohio EPA DERR recommends collecting oxygen and carbon dioxide data when conducting so
47. actices within this guidance will change as our understanding of vapor intrusion progresses Ohio EPA DERR will update this document as needed to accommodate refinements and advances in our understanding Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 1 of 104 2 0 SCOPE This guidance provides technically defensible and consistent approaches for evaluating vapor intrusion to indoor air based upon the current understanding of this exposure pathway This guidance document provides a technical framework for evaluating vapor intrusion and is not meant as regulation and does not impose any requirements or obligations on the regulated community Other technically equivalent procedures may exist Hence users of this guidance document can use other technically sound approaches Furthermore this guidance does not alleviate a volunteer or potentially responsible party from any obligations that U S EPA may require This guidance is meant to be used to evaluate the vapor intrusion to indoor air pathway only All other media characterization and evaluation of complete exposure pathways at a site must be done in accordance with the rules and procedures of the appropriate program VAP or RRP This guidance should not be used in lieu of a property specific risk assessment Rather this guidance is meant to supplement the requirements necessary to fully charact
48. al Canister Pressure Total Elapsed Sample psi or mm Hg Time hours Sample End Time ime interior Temperature Sub slab Screening Info F PID ppm Sample Delivery Date Oz AVERAGE REPORTED METEOROLOGICAL CONDITIONS FOR SAMPLING DAY Ambient Temperature High Low Barometric Pressure mm Hg Average Wind Direction Average Humidity percent Average Wind Speed mph NOTES Any Sampler or Canister problems or significant sampling details As operator certify that a valid canister sample has been collected and that this form has been completed Operator signature Phone SAMPLE RECEIVING Date Received Pressure Check psi Date Submitted Analytical Lab Sketch sampler location s in map on back of this data sheet Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 97 of 104 APPENDIX E Ohio Environmental Protection Agency Division of Emergency and Remedial Response Soil Gas Probe Field Data Report Form Soil Gas Probe Field Data Report Site Date Instrument s used Tracer used Weather Technician Soil Tracer Gas Probe Probe Purge Volume Field Other Probe Depth Volume Rate Purged Analysis indicators Number ft I lpm I ppmv or CO2 02 ppbv
49. allation At least three volumes should be removed For example the sample tubing can be purged using a 60 cc syringe with an attached 3 way valve 4 cc ft for 1 4 ID tubing volume Other methods may be used as long as a minimum of 3 volumes are purged from the tubing Once purging is complete the sample may be collected Field screening may be performed using a direct reading instrument Install new tubing in the bag sampler before collecting each sample Place a new Tedlar sample bag already labeled inside the bag sampler Attach the inside portion of the tubing to the inlet valve on the sample bag Open the sample valve on the sample bag following the manufacturer s instructions Close sampler lid and secure Attach external part of the inlet tubing to the sample tubing Make sure that the purge valve is closed closed for fastest fill rate open for slower fill rate Turn on the sample pump or initiate hand pumping While filling watch through the observation window of the Bag sampler as the Tedlar bag fills with gas Avoid filling bag more than 80 of its maximum volume Turn the pump off when the bag has filled to the desired volume Do not over fill sample bags The vacuum pump may be strong enough to break a sample bag NOTE Be sure to watch the sample line for the first sign of water coming up the line Pulling water up the line is not uncommon especially in cases where the position of the water table is unknown T
50. arge building may contain multiple identified areas and exposure units Separate vapor intrusion assessment of smaller enclosed spaces within a building footprint with multiple identified areas or separate buildings or areas within a large identified area is generally needed to assess the potential vapor intrusion exposure to the various receptors at a site MODELING THE VAPOR INTRUSION PATHWAY Ohio EPA recommends the U S EPA Johnson amp Ettinger J amp E model spreadsheets as a predictive tool for evaluating subsurface vapor intrusion into buildings The most current version should be used As of the date of this guidance the most current is Version 3 1 dated February 2004 While this guidance provides recommended acceptable J amp E model input values it does not include detailed discussions on the derivation or sensitivity of model inputs other than acceptable site specific model inputs For further information on model specifics please refer to the U S EPA Johnson and Ettinger Model User s Guide for Evaluating Subsurface Vapor Intrusion into Buildings For Voluntary Actions refer to the CIDARS database for appropriate toxicology for use in the model Oral slope factors SF and reference doses RfD are generally not extrapolated to assess inhaled exposures for compounds lacking inhalation values However for pathways where inhalation is the only exposure route it may be appropriate to extrapolate an oral value to an inha
51. articularly to the relationship between total and water filled porosity Because this and other soil input parameters can vary widely from region to region site specific soil parameters may be used when sufficient information is available to justify their use This guidance is not intended to be prescriptive in the methods of determining or estimating these soil variables It is recognized that standard geotechnical and geophysical methods exist for measuring or estimating these values J amp E input soil parameters most readily determined or estimated from site specific testing include soil bulk density total porosity water filled porosity and fraction organic carbon For the purposes of this guidance these are the soil input parameters These parameters can be determined directly following ASTM and other standard methods or can be estimated from field and laboratory measurements and or using equations describing soil phase solid water gas relationships Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 42 of 104 The first step in using site specific soil properties is to determine the proper United States Soil Conservation Service US SCS soil classification Figure 6 This classification system is referenced widely in the J amp E model User s Manual and is used by soil scientists and in agriculture However it is not widely used in the
52. as probably occurred For soil gas a similar evaluation can be conducted if routine sampling data is available from permanent or temporary sampling points If sufficient time has passed since the chemical release to allow for diffusional movement to the building in question then steady state conditions have probably transpired If contaminant plumes whether in soil gas or ground water are increasing 100 feet is not an appropriate distance for potential pathway elimination When evaluating the distances between subsurface contaminant plumes and buildings it is important to consider whether preferential pathways exist which could allow vapors to migrate more than 100 feet laterally These preferential pathways could be either natural or anthropogenic Examples of preferential pathways include fractures macropores gravel base for utility conduits and subsurface drains A checklist of information to assist in the development of a CSM for vapor intrusion and for planning a soil gas sampling strategy for a site can be found in Appendix C 3 3 Data Quality Objective Process The scope and objectives of environmental media sampling should be established before the study is conducted For voluntary actions the DQO process is part of the Site assessment site assessment see OAC 3745 300 07 C For RRP sites the CERCLA RI FS guidance should be followed when designing a sampling plan The DQO process establishes the scope and objectives of the ass
53. asaaeeaseeeeeeesasaaeeaseeeeseeeeseaesaaeeenseaenes 47 14 0 REMEDY a a era ites ae ar aa ra A a aa ae aaa aara Aae Aa Eaa aaaea eaa aaa Aadan Tadaa adada 49 viii TABLE OF CONTENTS CONT 15 0 REFERENCES iiaeaa aaa adaa aaaea aen a aaa aaa dat aea ea Ka deaa aiaa aa aaaea aoaaa da aakalain 51 LIST OF FIGURES Figure 1 Step Wise Approach for Evaluating the Vapor Intrusion Pathway sssssssssssnnnnnnnnnnnnn iv Figure 2 Examples of Soil Gas Sampling Probes and Well Material sccsssessseereeeeees 17 Figure 3 Permanent Soil Gas Probe Schematic ccescccsseeeeeeeeeeeeeeseeeseseeeeeeeeeeseeseseeeenseeeeeeees 18 Figure 4 Subslab Soil Gas Probe ccsscccseeeeeseeesseeeeeeeeeeeeeescaeensneeeeeeeessaessesneeenseeeseaesaseaeenseaeeenees 21 Figure5 Schematic of a Summa Canister cssecceeceeceseeesseeeeseeeeeeeeesecaeseseeeeeseeeseeeseseeeenseeeeeeees 27 Figure 6 U S Soil Conservation Service Classification Chart Showing Centroid COMPOSITION PnP a EPET A cece 43 LIST OF TABLES Table 1 Comparison Of Soil Gas Analytical Methods ccsccsseeseseeesteeseseeeeeeeeeseeeeseseeeeneeeeas 13 Table2 Common racers ii cccsesciccccecet seceded enciceviewncdarecnctcarrie wtecrisovccustdentaesVeonutessdanvacvveundaasddeasavdees 23 Table 3 Comparison Of Indoor Air and Subslab Sampling Conditions ssscsseeeeees 26 Table 4 Acceptable J amp E Model Inputs for Bulk Soil cccsseecsseeeeeseeeseeeeesee
54. ation screening Product Condition Source Y N ae ppm Paints or paint thinners Gas powered equipment cans Field Potential VOC Present screenin e source YIN Location ere Product Condition ppm Furie posh FO Motnbats fF fueltnk wose fF o SoS y o Fireplace a Pertumesicolognes T ooo y ore a ore a omer Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 102 of 104 Table 4 Potential vapor migration entry point information Potential Vapor entry points Foundation penetrations in floor or walls Present Y N Field screening results ppm Comments Cracks in foundation floor or walls Sump Floor drain Other Other Was the building aired out prior to sample collection How long was the airing out process Were vapor control methods in effect while the samples were being collected Windows open Yes No Vapor barriers Yes No Ventilation fans Yes No Vapor phase carbon treatment system Yes No Other site control measures Weather Conditions during Sampling Outside temperature F Prevailing wind speed and direction Inside temperature F Describe the general weather conditions e g sunny cloudy rain Significant precipitation 0 1 inches or more within 12 hours of the sampling event General Comments Is
55. ble Regulatory Standards CIDARS database Using the OSWER 2002 screening values at 1E 5 ECLR goal and HQ of 1 the resultant incremental risk and hazard ratios are then carried forward as part of the site wide risk calculation For RRP sites the U S EPA Regional Screening Levels see the RSL User s Guide residential air and the 2002 OSWER screening values can be used in conjunction with the above attenuation factors to develop screening levels for indoor air exterior or subslab soil gas data The ground water screening values in OSWER 2002 may also be used for sites in the RRP These screening levels 2002 OSWER or RSLs may be used to focus efforts on COCs by eliminating Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 32 of 104 COCs that are below levels considered to adversely impact human health as described in the Ohio EPA DERR Technical Decision Compendium TDC document titled Use of U S EPA s Regional Screening Levels as Screening Values in Human Health Risk Assessments Consistent with this TDC the screening value for each COC would be the residential value listed on the RSL table for carcinogenic COCs at the 1E 6 risk goal and an adjustment of 0 1 the value for non carcinogenic COCs Similarly the 2002 OSWER screening values should be selected from the table listing the ELCR goal of 1E 06 Table 2c In addition becaus
56. bmerged below the top of the water table However additional assessment of the plume may be necessary to demonstrate that the vapor intrusion pathway is not a concern for a downgradient receptor Screen Lengths Monitoring wells with long well screens regardless of screen placement should not be used to make vapor intrusion evaluations When sampling long well screens clean water entering the well screen at depth may dilute the contaminated ground water near the top of the screen biasing the sampling results and the associated risk determination Hence short screen lengths are preferred for monitoring wells that will be used to make vapor intrusion evaluations Ideally the saturated thickness in a well screen should be less than 10 feet Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 29 of 104 9 0 Well Sampling Ohio EPA prefers low flow sampling bladder pumps or submersible pumps These pumps minimize the loss of VOCs during sample collection and handling For well characterized sites ground water can be sampled with diffusion bags following the procedures in Interstate Technology and Regulatory Council 2004 However if COCs in ground water collected using diffusion bags are near risk levels the determination that risk goals are met may need to be verified using bladder or submersible pump sampling techniques For properties where
57. bslab Depressurization Systems for Mitigation of Chlorinated Solvent Vapor Intrusion Presented at U S EPA Seminars on Indoor Air Vapor Intrusion December 2002 January 2003 February 2003 U S EPA Office of Research and Development Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 51 of 104 Hartman Blayne October 2002 How to Collect Reliable Soil Gas Data for Risk Based Applications Part 1 Active Soil Gas Method LUSTLine Bulletin 42 Hartman Blayne November 2004 How to Collect Reliable Soil Gas Data for Risk Based Applications Part 3 Answers to Frequently Asked Questions LUSTLine Bulletin 48 Hartman B 2008 Results from EPA Research Programs on Sample Flow Rate Purge Volume Tubing Type Tedlar Bags amp Temporal Variations On Soil Gas Concentrations Cal EPA Soil Gas Forum Los Angeles CA March 4 2008 http www dtsc ca gov Assessing Risk upload Hartman pdf Hayes H N Khan and D Benton 2006 Impact of Sampling Media on Soil Gas Measurements In Proceedings Air and Waste Management Association s Vapor Intrusion Symposium The Next Great Environmental Challenge An Update Los Angeles CA p 69 83 September 13 15 2006 Hewitt A D 1994 Concentration Stability of Four Volatile Organic Compounds in Soil Subsamples US Army Cold Regions Research and Engineering Laboratory Special Report 946
58. cific value which is considered representative of the soil layer Again the selected value should fall within the practical range of values for that parameter as shown in the User s Guide If the selected value does not fall within this range the modeler should provide sufficient justification for the use of the selected value Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 45 of 104 12 0 EVALUATION OF IMMINENT HAZARD IN AN EXISTING BUILDING If data evaluation indicates the possibility of an imminent hazard from a known or suspected nearby source immediate action is necessary to verify or abate threats to human health For the purposes of this guidance imminent hazard is defined as any condition which poses a significant immediate risk of harm to public health safety or the environment This action may be limited to the prompt implementation of a vapor intrusion investigation Alternately the decision may be made that an interim or emergency remedial measure is required For any site in the RRP or VAP Ohio EPA Division of Emergency and Remedial Response should be contacted immediately if data collection indicates the possibility of an imminent hazard Ohio EPA s Spill Hotline number is 1 800 282 9378 The following list contains examples of indicators for the potential of an imminent hazard Known spill in a structure e g heatin
59. cipitation can produce drastically reduced or non existent readings NOTE Separation between the contamination source and the sample location increases the influence due to biodegradation or abiotic transformation 2 0 Health and Safety Warnings 2 1 Overhead and Buried Utilities The use of direct push systems on a site within the vicinity of electrical power lines and other utilities requires that special precautions be taken by the operators Underground electrical utilities are as dangerous as overhead electricity Be aware and always suspect the existence of underground utilities water natural gas cable phone lines fiber optic cables storm water amp sewer lines etc REMEMBER Call B 4 U Dig Ohio Utilities Protection Service OUPS 800 362 2764 amp Oil amp Gas Producers Underground Protection Service OGPUPS 800 925 0988 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 64 of 104 2 2 Operators must wear OSHA approved Personal Protective Equipment PPE Refer to the site specific Health and Safety Plan 3 0 Apparatus and Materials 3 1 The following is a list of equipment tooling and supplies typically used for soil gas sample collection PPE e Hearing protection e Safety glasses e Nitrile or similar disposable gloves Leather gloves e Steel toed boots e Hard hat Equipment T ooling Supplies ne
60. ction activities Additionally avoid locations where reactive surfaces may cause chemical changes in the air sampled directly above contaminated soil or locations what may influence the ability to collect a representative sample such as nearby hills structures bodies of water etc Intake probes for the ambient air sample s should be placed at a representative height such as breathing zone height or between 6 to 8 feet 3 to 15 meters above the ground Locations near the structures should extend at least 3 to 4 feet 1 to 2 meters away from the structure If located on a building the sample equipment should be mounted on the windward side Additional considerations Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 88 of 104 3 0 4 0 for the collection of ambient air sample s are located in section 8 0 Sample collection times may vary depending on the scope of the project It is important to return to the sample location at least 30 to 60 minutes prior to the end of the sample collection time Sampling stops when the flow regulator valve is turned off Final notes are made regarding the sample stop time and final vacuum pressure Sample Preservation Containers Handling and Storage 3 1 SUMMA Canister Sampling After the indoor air soil gas sample is collected the canister valve is closed an identification tag is attached to
61. ction and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 86 of 104 CONSTRUCTION AND INSTALLATION OF PERMANENT SUB SLAB SOIL GAS WELLS FIGURE 6 1 4 OD TEFLON TUBING SOIL GAS PROBE PREPARED FOR SAMPLING ais lt 1 4 OD TEFLON TUBING SWAGELOK SS 406 7 4 FEMALE ADAPTER SWAGELOK MALE TEE SS 400 3 4TTIM SWAGELOK MALE TEE S8 400 3 4TMT ih E 1 DIAMETER OUTER HOLE 13 8 ANCHORING CEMENT 1 4 SWAGELOK NUT MODELING CLAY OR TEFLON WASHER 1 4 OD STAINLESS STEEL TUBING lt 3 8 DIAMETER INNER or PILOT HOLE SUB SLAB MATERIAL Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 87 of 104 SOP 2 5 3 Procedures for Collection of Indoor Air 1 0 2 0 Scope and Application This standard operating procedure SOP describes the procedures used for the collection of ambient and indoor air vapor samples Indoor air samples are collected from predetermined locations within buildings and structures and are typically analyzed for volatile organic compounds VOCs using U S Environmental Protection Agency Method TO 15 Ambient air samples are collected at the same time and for the approximate same duration as the indoor air sample s Method Summary This method uses an evacuated 6 lit
62. d Default values defined values from geotechnical porosity Sand data E Site specific value Enclosed floor 10 cm Can be site specific in lieu of requires documentation space thickness default values May require O amp M Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 40 of 104 kk Table 5 Acceptable J amp E Model Inputs for Soil Gas and Ground Water Variable Default Value Comments Can be site specific in lieu of Restrictions Site specific value width Soil bldg pressure 2 40 g cm s requires documentation differential default values May require O amp M Enclosed floor Larger value may require space length ee JAE natau deed restriction Enclosed floor 1000 cm J amp E default Larger value may require deed restriction Enclosed floor 10 feet 304 8 Typical average ceiling height Larger value may require Quotient height cm deed restriction Floor wall seam 0 1 cm 0 1 cm is the minimum value crack width accepted Deed restriction required Indoor Air Assuming residential land use f commercial industrial Exchange Rate eon 1 0 hr for commercial industrial Oihar tales dees documentation and may require O amp M aa rg 5 L min use 5 L min or allow model to nee calculate based on soil type building AT Non carcinogens 30 years R
63. d for the evaluation of the vapor intrusion pathway is dependent on the release history prior site investigations the CSM and whether the site is being evaluated under the VAP or RRP For VAP sites the sampling strategy may depend on whether or not the remedy includes mass removal or pathway blocking mechanisms For RRP sites the sampling strategy is directed by the RI FS process including the CSM amp RI workplan and is completed as part of the site characterization step of the RI The sampling strategy should be sufficient to characterize the complete nature and extent of contamination During site characterization the sampling and analysis plan that was developed during the project planning is implemented and field data are collected and analyzed to determine if a complete vapor intrusion pathway exists and to what extent the site poses a threat to human health and the environment This is an iterative process and the resulting data and information will be used for selecting a remedy for the site Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 8 of 104 In most cases soil gas data is part of the multiple lines of evidence approach to determine whether the vapor intrusion pathway is potentially complete If ground water and soil matrix data are used instead of actual soil gas data the data must be converted to vapor concentrations using assum
64. data may be collected or a remedy may be implemented If collected data indicates that risk goals may be exceeded then further data collection analysis and evaluation may be necessary in order to make a decision based on multiple lines of evidence Alternatively a remedy can be conducted to prevent exposure from subsurface vapors Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 48 of 104 14 0 REMEDY Flowchart Step 8 Remediation Mitigating Indoor Air Exposure and or Conducting Long Term Monitoring A remedy or a combination of remedies can be implemented to mitigate or eliminate risks from vapor intrusion Remedies can generally be separated into three main types 1 remediation of environmental media 2 institutional controls and 3 building controls Please note that some remedies may include long term operation and maintenance including monitoring For VAP please see 3745 300 11 for specific remedy requirements For RRP properties Ohio EPA will direct the remedy selection based on existing RRP U S EPA guidance e g RIFS SCIA Three recommended documents that provide a detailed assessment of remedies that address impacts from the vapor intrusion exposure pathway are 1 Indoor Air Vapor Intrusion Mitigation Approaches Office of Research and Development EPA 600 R 08 115 October 2008 2 U S EPA Brownfields Technology Primer
65. dation the results from nearby soil gas sampling and the site specific DQOs At least two subslab soil gas samples should be taken with one sample taken in the center of Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 19 of 104 the building s foundation For foundations greater than 5000 square feet Ohio EPA suggests that at a minimum subslab soil gas be collected from biased locations e g directly over source areas maximum ground water concentration areas or near preferential pathways If indoor air sampling is subsequently needed the indoor air samples should be analyzed only for the chemicals detected in the subslab soil gas see Section 6 0 During subslab soil gas sampling be careful not to damage the integrity of the slab Subslab utilities or tension cables need to be located prior to selecting sampling locations Blueprints can assist in locating these features Since penetrating the slab creates a preferential pathway proper sealing of the sampling port is essential to avoid leaks Subslab soil gas sampling should be avoided in areas where ground water might intersect the slab Figure 4 is a schematic of a subslab soil gas probe Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 20 of 104 1 4 OD Teflon Tubing Swagelok SS 400 1 4
66. decision based on site specific circumstances and each individual project s DQOs For details on collecting indoor air see Figure 5 and SOP 2 5 3 The sample duration should be reflective of the site specific exposure scenario that represents the true time integrated average concentration to which an inhabitant may be exposed When evaluating exposure for a residential scenario a 24 hour sample duration should provide a representative sample For non residential sampling such as a work place scenario a sampling duration commensurate with exposure may be appropriate For commercial exposures an eight hour minimum sampling duration is required Ideally the duration and frequency of sampling should cover the range of conditions that may influence concentrations Seasonality can affect COC concentrations in groundwater as well as the rate of vapor intrusion and indoor air concentrations Thus groundwater indoor air subslab soil gas and or exterior soil gas samples may need to be collected on a quarterly basis to adequately account for temporal variation Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 26 of 104 INLET FILTER ON i FLOW CONTROLLER j Somat FLOW CONTROLLER Se P N 4 2 As d 20 16 AN 25 N lt N 30 Ly i X PA 1 4 SWAGELOK FITTING TO SUMMA CANISTER 5 1 4 SWAGELOK FITTING FRONT VIEW OF GAUGE ON FLOW
67. default soil type unless site specific geotechnical data including grain size analysis is collected in accordance with this guidance 11 3 Soil Gas and Ground Water Table 5 summarizes the acceptable J amp E model input parameters for use with the advanced soil gas and ground water models Sand is the default soil type unless site specific geotechnical data including grain size analysis is collected in accordance with this guidance After evaluation through the J amp E modeling and considering the presence of multiple chemicals the site may be further investigated through additional exterior and or subslab soil gas sampling For commercial or industrial properties with existing buildings collecting subslab soil gas data is preferable Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 37 of 104 Table 4 Acceptable J amp E Model Inputs for Bulk Soil Variable Default Value Comments Restrictions Average soil temperature 11 degrees C Depth below Deed restriction may grade to i5 em and 200 Run model with slab and basement Ee oe bottom of unless building already exists in which g enclosed floor space cm case use current building characteristics other types of construction as needed Depth to below grade to top of contamination Site specific Depth to below grade to bottom of contamination Site specific Use
68. del for Subsurface Vapor Intrusion into Buildings J amp E Model The J amp E Model has several associated assumptions and limitations Review the CSM to ensure that use of the J amp E Model is appropriate Update the CSM depending on the outcome of data evaluation Step 6 Step 7 Step 8 If data indicate the possibility of an imminent hazard Ohio EPA should be contacted as soon as possible Evaluate the potential risk and hazard from the vapor intrusion pathway For RRP sites if data evaluation indicates that concentrations are below screening values those COCs are eliminated from further vapor intrusion assessment For VAP properties the screening values are used to calculate incremental site wide risk If data evaluation indicates risk or hazard goals are or may be exceeded then additional data may be collected or a remedy may be implemented see Step 8 If there is a potential for unacceptable risk further investigation may include the following e Collecting data to define physical and chemical parameters for site specific soil using recommended test methods e Collecting soil gas samples to define the vapor plume at sites where buildings do not exist e Collecting subslab soil gas samples or crawl space samples at an existing building e Collecting indoor air samples in conjunction with subslab soil gas samples e Additional evaluation of the environmental data may be needed to derive an exposure point concentrati
69. ding control remedies can be used to reduce or eliminate the potential for vapor intrusion impacts in new and existing buildings Some examples of available technologies are provided in Table 6 along with some of the advantages and disadvantages of each ITRC 2007 Table 6 Comparison of Mitigation Methods Technology Typical Applications Challenges Passive barrier New construction Crawl spaces Often combined with passive or active venting sealing openings in the slab drains etc Preventing tears holes May not suffice as a stand alone technology Some states do not accept Ensuring caulking seals cracks in floors etc Passive venting New construction Low soil gas flux sites e Should be convertible to active system if necessary Relies on advective flow of air due to wind and heat stack effects Air flows and suction typically far less than achieved by fans Aerated floor New construction or extensive remodeling May be useful for large structures Not yet widely used May not be suited for all soil types New and existing structures Subslab ee e Sumps drain tiles and block e Low permeability and wet soils may limit depressurization wall foundations may also be performance SSD depressurized if present S bm mbra e e Existing structures e Sealing to foundation wall pipe penetrations depressurization e Crawl spaces e Membranes may be damaged by occupants o
70. e data etc The work plan should be finalized before any sampling is conducted The work plan will provide specific information on the type and quality of data gathered during the soil gas sampling event Any questions regarding data needs and usage should be resolved prior to sampling Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 63 of 104 1 4 1 5 The evaluation of the indoor inhalation pathway at contaminated sites is a relatively recent development As a result procedures and technology related to evaluating the pathway continue to evolve This guidance pertains to the active collection of soil gas using direct push systems i e driven probe rod see also ITRC Vapor Intrusion Guidance A Practical Guide January 2007 Appendix D Section 4 Ohio EPA does not intend for this guidance to be overly limiting with respect to the use of other appropriate methods procedures and equipment for measuring concentrations of chemicals of concern in soil gas Limitations 1 5 1 A soil gas survey is only applicable to volatile contaminants 1 5 2 Barriers exist that interfere with vapor migration such as perched water clay or man made structures can lead to non representative sampling with low or false negative readings or may produce localized areas of high concentrations 1 5 3 Soil gas readings taken within 24 to 48 hours of heavy pre
71. e secondary structures if vapors in primary structures are at unacceptable risk levels This step out process should be conducted in a sequential manner until a perimeter of structures with concentrations at acceptable risk levels is defined DERR recommends that subslab soil gas samples be collected concurrently and of similar duration to the indoor air samples results so that a direct comparison of the data can be made However indoor air samples may be collected after review of the subslab soil gas results Whenever collecting indoor air samples ambient air outdoor samples are required in order to compare the chemicals found inside the structure with concentrations of COCs present in ambient air Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 24 of 104 It is important to limit COC selection to only those found in media and subslab For larger facilities indoor air background samples should be collected to address contribution from building materials operations or product material storage When reviewing indoor air data it is important to distinguish between background contaminants and contaminants as a result of vapor intrusion Subslab soil gas data combined with indoor air data can be particularly helpful in determining when COCs are likely to be present from background sources Also when evaluating indoor air data the ratios of
72. e the OSWER screening values for noncarcinogens are based on an HQ of 1 these values should be multiplied by 0 1 to develop the appropriate screening levels Please note that Ohio EPA DERR is not using the toxicity criteria listed in the OSWER 2002 guidance document for trichlorethene TCE CAS No 79016 Presently toxicity criteria from California EPA is being used for TCE Please contact the site coordinator and or risk assessor for updated toxicity criteria on this and other potential COCs COCs with maximum concentrations that are less than the corresponding screening levels may be excluded from a human health risk evaluation providing that the current and future use of the site is not anticipated to result in exposures greater than those used in the derivation of the screening values 10 2 Data Analysis If ground water and or soil data indicate the potential for vapor intrusion a soil gas sampling program should be conducted to delineate the extent of the subsurface vapor plume The results of soil gas sampling should then be compared with the program specific soil gas screening levels Where soil gas samples do not exceed the screening levels but ground water exceeds the screening levels further site characterization is recommended to further assess the vapor intrusion pathway This evaluation would require an understanding of the site conceptual model and should take into consideration the following e Shallow ground water concentrat
73. e the plug during the next sampling event the probe may break loose from the anchoring compound Refer to Section 7 3 if the probe breaks loose from the anchoring compound during this step Repairing a Loose Probe Assembly 7 3 1 If the probe assembly breaks loose from the anchoring compound while removing or installing the hex socket plug the Swagelok male connector or the barbed hose adapter lift the probe assembly slightly above the surface of the concrete slab 7 3 2 Hold the female connector with the 3 4 open end wrench 7 3 3 Complete the step being taken during which the probe broke loose following the instructions contained in this SOP e Do not over tighten the hex socket plug the male connector or the barbed hose adapter 7 3 4 Push the probe assembly back down into place and reapply the anchoring cement grout Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 80 of 104 8 0 9 0 7 3 5 Modeling clay verified to be VOC free may be used as a temporary patch to achieve a seal around the probe assembly until the anchoring cement grout can be reapplied Quality Assurance Quality Control An additional co located soil gas port is installed at a frequency of 10 1 in 10 or as specified in the site specific Quality Assurance Project Plan QAPP The following general Quality Assurance QA procedures apply 8 1
74. eded for all probing e 4 foot probe rods e 2 foot probe rods e Inner Extension Rods 48 e Rod Grip Pull System e Drive Cap e Pull Cap e Miscellaneous tools e Logbook Bentonite granules Soil Gas Sampling Expendable Point Holder e Y4 Tubing Teflon Nylon Expendable Drive Points w O ring or PEEK Adapter for 1 4 tubing w O ring e 20 40 grade sand Tedlar gas sampling bags 1 L e Implants stainless steel w bag sampler e g Lung Box aluminum ceramic or plastic e Implant Expendable Point Holder e Funnel e Air tight fittings valves e Vacuum canisters e g e Expendable Point Popper Summa e Plastic or stainless 3 way valves e 60cc Syringe e Equipment for leak testing e Multi gas meter Equipment Clean Up e Decontamination Supplies e Non phosphate Soap e Various Brushes e Tap amp ASTM Water e Pressurized Sprayer e Wash Tubs Buckets e Polyethylene Sheeting Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 65 of 104 4 0 Summary of Probe Installation Methods 4 1 Post Run Tubing System This is a temporary single use application for collecting a grab soil gas sample Using the post run tubing system PRT probe rods are driven to the desired depth and then internal tubing is inserted and sealed for soil gas sampling Using the inner tubing for soil gas collection has many advantages potential for leakage is
75. eeeeeeesseaeenseeneeeeees 38 Table5 Acceptable J amp E Model Inputs for Soil Gas And Ground Watel sccsssssseeseees 40 Table 6 Comparison of Mitigation Methods c ecccsscsesceseeeeeseeeeeneeesneeeeneeeeseeesesnaesnseeeeeeeeess 50 LIST OF APPENDICES Appendix A Chemicals of Concern for Vapor intrusion c sccseeeeeseeseeeeeseeeeeeeeeeseeeenseeeeeseees 56 Appendix B Special Considerations for Evaluating Residential Properties 0 00 59 Appendix C Vapor Intrusion Conceptual Site Model Checklist cccssseeeeeeseseeeeeseeeees 60 Appendix D Standard Operating Procedures for Sample Collection cccssseeeeeseeees 62 SOP 2 5 1 Procedures for Active Soil Gas Collection Using Direct Push Systems 008 63 SOP 2 5 2 Construction and Installation of Permanent Subslab Soil Gas Ports ceeee 75 SOP 2 5 3 Procedures for Collection of Indoor Air eccccceeeeeeeeeeeeeceeeeeeeeeeseeeeeseeeeenaeeseeeseeeees 88 Appendix E Soil Gas Probe Field Data Report Form ccssecceseesseeseseeeeneeeeeseeeseseeeeneeeeeeseees 98 Appendix F Indoor Air Sub Slab Sampling Form cccsccsseccsseeeeeeeeeseceeeeseeeeeeeeeseeeseseaeenseeeeeeeeess 99 Appendix G Comparison of Tubing Type to Vapor Absorption 0 cccssseeeeesseeeeneesesenes 104 1 0 INTRODUCTION VOCs whether in soil or ground water can migrate through the subsurface and enter into buildin
76. eflon tape is needed Tighten the plug slightly Do not over tighten If excessive force is required to remove the plug during the sample set up phase the probe may break loose from the anchoring cement Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 77 of 104 Assembled subslab port ready for installation 7 1 7 Place the completed probe into the outer hole to check fit and to ensure that stainless steel tubing is not in contact with the subslab material Make necessary adjustments to the hole or probe assembly 7 1 8 In a disposable cup or other container mix a small amount of the anchoring cement or grout Add water sparingly to create a mixture that is fairly stiff and moldable Place a spoonful or two of the cement grout around the stainless steel tubing adjacent to the female connector nut Mold the cement grout into a mass around the connector nut and up around the main body of the probe assembly Slide the Teflon washer onto the stainless steel tube so that it rests next to the cement grout mixture The washer will prevent any anchoring cement grout from flowing into the inner hole during the final step of probe installation 7 1 9 Carefully place the probe assembly into the drilled hole applying light pressure to seat the assembly While inserting the probe assembly work the concrete grout mixture to fill voids Clean up ceme
77. er SUMMA passivated stainless steel canister for sample collection A flow regulator with vacuum gauge is attached to the canister in order to collect a volume of sample over a pre determined time span Location s for the placement of the canisters within the building s or structure s are also pre determined in order to focus sampling efforts on potential receptors within the building s structure s The outdoor ambient sample must be collected at approximately the same time and for the same time interval as the indoor air samples see section 8 0 Oral interviews and a written questionnaire for building inhabitants are required prior to the sampling event this step is necessary to reduce and or eliminate the impact of inhabitant activities on the analytical results see Indoor Air Sampling Form Once the flow regulator is attached to the canister the valve on the regulator is opened Notes are made regarding the project building location address of building and placement of canisters canister ID number flow regulator ID number sample start time canister pressure inches of Hg and the samplers performing the sampling event see Attachment 2 Canister Sampling Data Sheet Ambient air sample locations should be in an area that has unobstructed airflow especially in the direction of any recognized sources of the materials being sampled Locations should be avoided that will potentially have a negative effect on the sample colle
78. erize risk at a site For purposes of this guidance the term site also includes property as defined in OAC 3745 300 01 105 This guidance assists in addressing but is not limited to the following questions What sites are candidates for potential risks from vapor intrusion to indoor air e What site characterization data are needed to conduct a vapor intrusion evaluation e What methods are recommended for sampling subsurface media and indoor air Should indoor air sampling be conducted e What are the data requirements for an evaluation of the vapor intrusion pathway e How are vapor intrusion models used and what are the appropriate site specific inputs What measures are available to mitigate indoor air exposures Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 2 of 104 3 0 VAPOR INTRUSION EVALUATION OVERVIEW 3 1 The following text describes the step wise approach for evaluating vapor intrusion found in Figure 1 The step wise approach in this guidance document is meant to be flexible and may be tailored to site specific circumstances Pathway evaluation may begin at any step provided that the data collection and the CSM clearly justify the entry step However it is important to note that a vapor intrusion exposure pathway is assumed to be complete unless shown otherwise For this reason soil gas dat
79. esidential land use AT Non Commercial Industrial Canine jie 25 years Commercial Industrial land use values would require 9 deed restriction ED 30 years Residential land use Commercial Industrial ED 25 years Commercial Industrial land use values would require deed restriction EF 350 days year Residential land use Commercial Industrial EF 250 days year Commercial Industrial land use values would require deed restriction No other value accepted except Target Risk 1 E 5 for industrial land use only for VAP properties 1E 04 Target Hazard 1 0 No other value accepted Use of all property specific soil types requires geotechnical analysis Please see sections 11 5 and 11 6 of this guidance for residential 8 feet for slab and 12 feet for basement for a residential May not be appropriate to use whole building height as one big box model since likeliest highest concentrations of volatiles will be in the lowest levels based on property specific data Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 41 of 104 11 4 Acceptable J amp E Model Input Parameters Tables 4 and 5 of this guidance summarize the acceptable J amp E Model input parameters for bulk soil and soil gas and ground water respectively It is important to note here that the target risk goal is 1 E 6 for cancer risk and 0 1 for target hazard quotient for the bulk soil assess
80. essment before sampling is conducted The DQOs are qualitative and quantitative statements that Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 7 of 104 e Clarify the study objective e Identify the chemicals of concern COCs e Define if the sample will provide qualitative or quantitative information e Define the type quantity and quality of each piece of data collected in the study e Determine required analytical detection limits Define how each sample will be used to assess if vapors are intruding into buildings e Determine the most appropriate locations sampling method and sampling duration for data collection Specify the amount of acceptable uncertainty in the sampling results Specify how the data will be used to test the exposure hypothesis Additional information on the DQO process can be found in U S EPA 2006 Guidance on Systematic Planning Using the Data Quality Objectives Process Office of Environmental Information Washington DC EPA 240 B 06 001 See Also Ohio EPA Division of Emergency and Remedial Response Data Quality Objectives Process Summary DERR 00 DI 32 2002 3 4 Sampling Strategy Flowchart Step 4 If the CSM indicates that the vapor intrusion pathway is potentially complete sample soil ground water subslab soil gas and or exterior soil gas The type of environmental media sample
81. et 10 feet and 20 feet below ground surface bgs Deeper samples should be collected as needed to define vertical trends in vapor concentrations Ohio EPA DERR recommends that two rounds of exterior soil gas data be collected when eliminating vapor intrusion as an exposure pathway The two rounds should account for temporal and seasonal variations at the site and other site specific factors which may influence the migration of vapors The maximum concentration detected should be used to evaluate risk If exterior soil gas samples exceed screening values then subslab soil gas samples should be collected At most sites exterior soil gas samples should not be collected at depths shallower than 5 feet bgs due to potential atmospheric interference For sites where the depth to ground water is less than five feet an attempt should be made to collect soil gas samples from beneath existing impermeable surfaces such as garage floors patios parking lots or roads etc If an impermeable surface is not present it may be more appropriate to rely on additional lines of evidence such as passive soil gas sampling and groundwater sampling If shallow soil sampling is performed leak testing is a critical element of the sampling Section 5 0 Subslab crawl space or indoor air sampling may be more appropriate in this situation Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action
82. fault require deed restriction T Larger value may EN ie ii Typical average ceiling height require deed g restriction Floor wall seam crack 0 1 cm Minimum value accepted width ee 0 25 hr Assuming residential land use Restriction required if rat 9 1 0 hr for commercial industrial commercial industrial Average vapor flow 5 L min use 5 L min or allow model to calculate rate into based on soil type building AT non 30 years Residential land use assumed carcinogens AT non Commercial Industrial carcino sne 25 years Commercial Industrial land use values would require a deed restriction ED 30 years Residential land use assumed Commercial Industrial ED 25 years Commercial Industrial land use values would require deed restriction EF 350 days year Residential land use assumed Commercial Industrial EF 250 days year Commercial Industrial land use values would require deed restriction Target risk 1 E 6 No other value accepted Target hazard 0 1 No other value accepted quotient Use of all site specific soil types requires geotechnical analysis Please see sections 11 5 and 11 6 of this guidance for residential 8 feet for slab and 12 feet for basement for a residential May not be appropriate to use whole building height as one big box model since likeliest highest concentrations of volatiles will be in the lowest levels based on site specific data Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohi
83. g oil tanks Physiological effects reported by occupants with a known or suspected source nearby Wet basement or sump with contaminated ground water nearby Chemical solvent or petroleum odor reported in a structure with a known or suspected source nearby Free product at the water table under or immediately adjacent to a structure and Other short term safety concerns Consistent with the U S EPA 2002 short term safety concerns are known or are reasonably suspected to exist including a measured or likely explosive or acutely toxic concentrations of vapors in a building or connected utility conduits sumps or other subsurface drains directly connected to the building and b measured or likely vapor concentrations that may be flammable combustible corrosive or chemically reactive Professional judgment should be applied to these qualitative criteria when a determination is made that an imminent hazard is present The condition in question should be related to an event or observation in or immediately adjacent to the potential affected structure As with all indoor air sampling events the investigator should properly assess the relative impact from background sources on the overall indoor air quality Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 46 of 104 Note that methane is not part of this vapor intrusio
84. generally considered semivolatile they may become degraded over time The mono and dichlorobiphenyls which can be produced during this natural degradation process are volatile Although the mono and dichlorobiphenyls are not poly chlorobiphenyls they are considered members of the PCB chemical class Studies have shown that in areas with high PCB concentrations up to 98 of the indoor air concentrations were due to monochlorobiphenyls Davis et al 2002 Thus site specific conditions will determine whether there is a likely vapor intrusion pathway due to PCBs It is not likely that sites with minor PCB issues such as the presence of transformer pads will necessitate an evaluation for the vapor intrusion pathway Please contact a DERR risk assessor for further information on how to evaluate congener specific PCBs for the vapor intrusion pathway Methane is not specifically addressed in this guidance although some of the procedures described may apply to evaluated sites with methane Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 4 of 104 Flowchart Step 3 If there is a potential release of any COCs listed in Appendix A develop a conceptual site model CSM and Data Quality Objectives DQOs for evaluating the vapor intrusion pathway 3 2 Conceptual Site Model The CSM is part of all site investigations The purpose of a CSM is to pro
85. gs causing an unacceptable chemical exposure for building occupants If VOCs are present at a site Ohio EPA DERR requires that risk to potential exposure from vapor intrusion be included in the human health risk evaluation This guidance provides a framework for site characterization and investigation of the vapor intrusion exposure pathway Evaluation of the indoor air exposure pathway involves characterizing subsurface VOC releases obtaining appropriate environmental data potential use of fate and transport models to predict indoor air concentrations from vapor intrusion and conducting indoor air sampling if necessary This guidance outlines the technical aspects of evaluating this exposure pathway and provides recommendations for elements that should be included in a site facility investigation Due to the complexity of vapor intrusion many professional disciplines may be needed to evaluate and mitigate exposure Accordingly an appropriate project team should be gathered when evaluating vapor intrusion issues This guidance is not intended to provide detailed information on conducting a baseline or property specific risk assessment Ohio EPA anticipates that this guidance will be used by regulators responsible parties environmental consultants community groups and property developers Because vapor intrusion is a developing field many technical aspects are not well understood Hence it is anticipated that some of the procedures and pr
86. hio EPA Division of Emergency and Remedial Response 2002 Data Quality Objectives Process Summary DERR 00 DI 32 January 2002 Ohio EPA Division of Emergency and Remedial Response 2009 Applying Generic Petroleum Standards Under the Voluntary Action Program VA30008 09 01 March 2009 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 53 of 104 Ohio EPA Division of Emergency and Remedial Response 2009 Use of U S EPA s Regional Screening Levels as Screening Values in Human Health Risk Assessments August 21 2009 Ouellette G 2004 Soil Vapor Sampling and Analysis Lessons Learned Presented at the Department of Energy Petroleum Environmental Research Forum Soil Vapor Workshop http www perf org pdf Ouellette pdf Roggemans S C L Bruce and P C Johnson December 2001 Vadose Zone Natural Attenuation of Hydrocarbon Vapors An Empirical Assessment of Soil Gas Vertical Profile Data American Petroleum Institute Technical Report Schuver Henry U S EPA OSWER Use of Soil Gas Data in Vapor Intrusion Decisions 17th AEHS West Coast Conference on Soils Sediments and Water San Diego CA March 21 22 2007 U S Department of Agriculture Natural Resources Conservation Service Handbook 18 1993 Soil Survey Manual Figure 3 16 pp 62 65 U S EPA October 1993 Radon Mitigation Standards EPA 402 R 93 078 Revi
87. his is a good reason why ample lengths of tubing should be used for the sample line If water is drawn up the tubing the tubing can be cut before the water reaches the sampling equipment NOTE Exercise extreme caution if filling sample bags with explosive gases Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 72 of 104 5 2 5 3 5 4 5 1 1 5 5 1 1 6 Once filling of the sample bag is complete turn off the pump open the purge valve to equalize the pressures unlatch the bag sampler lid and open Close the sample bag inlet valve by holding the side stem and turning the entire upper portion of the fitting clockwise until snug Remove the filled sample bag from the internal inlet tubing If measurements with a portable meter are to be made e g oxygen conduct measurements after collecting the soil gas sample s Peristaltic Pump 5 2 1 5 2 2 5 2 3 5 2 4 Connect the Teflon sample tubing to the peristaltic pump tubing The exact tubing connection method is up to the sampler However ensure that all connections are secure without leaks Use hose clamps to secure tubing if needed or desired Turn on the peristaltic pump and set the pumping rate such that the Tedlar bag fills at approximately one minute 1 liter min pump rate Once the gas sample is collected turn off the pump close the valve on the bag and
88. hould be cut at 10 5 feet Cover or plug the open end of the tubing with a sealed fitting or valve Lower the implant and tubing down the inside of the probe rods until the implant hits the top of the anchor drive point Note the length of the tubing to assure that proper depth has been reached If using attachable steel implants rotate tubing and attached steel implant counter clockwise while exerting a gentle downward force to engage the implants threads into the threads of the expendable point Pull up on the tubing lightly to test the connection DO NOT cut the excess tubing at this time Position the rod grip pull system or rod pull plate on the top probe rod Exert downward pressure on the tubing while slowly pulling the probe rods up Pull up about 12 inches or twice the distance of the implant length to create an annulus for backfilling with sand or rounded glass beads If using 1 4 O D tubing or smaller thread excess tubing through a funnel and position it over the top of the probe rod If using larger tubing e it may not be possible to install the sand since the spacing between the outside of the larger tubing and the probe rods has been reduced and may not allow sand to sufficiently flow to the bottom of the tool string Bridging of the sand is most likely to occur in this scenario Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Ac
89. ial for unacceptable risk due to vapor intrusion Indoor air sampling may also be necessary under other circumstances where exterior or subslab soil gas sampling is not viable such as ground water elevations in close proximity to the foundation during or after corrective actions have been taken or where preferential pathways exist that would limit the usefulness of ground water or soil gas data There are several steps that should be considered when conducting indoor air sampling as part of a vapor intrusion pathway assessment Define the study goals and DQOs Identify the VOC s including parent and breakdown products Building inspection and product inventory see Section 6 2 Select number and location of indoor sampling locations Select the number and location of exterior ambient sampling locations Select duration of sampling event based on DQOs and risk assessment needs e Select sampling method with appropriate detection limit e Establish QA QC requirements When planning indoor air sampling to assess large plumes that have the potential to impact a significant number of structures Ohio EPA DERR recommends a tiered approach identifying primary the most at risk and secondary structures based on ground water concentrations structural characteristics exterior soil gas concentrations and subslab soil gas concentrations Conduct indoor air sampling at the primary structures first Expand the scope of indoor air sampling to th
90. ides the framework for the site characterization and risk assessment for the vapor intrusion exposure pathway It is not necessary to investigate a site for potential vapor intrusion risk in the order presented in this guidance For sites where the environmental release history is unknown the step wise approach should be most useful and effective However many sites in DERR programs have been assessed in some manner prior to investigating potential vapor intrusion issues Therefore entering the flowchart at various steps may be appropriate Figure 1 Step Wise Approach for Evaluating the Vapor Intrusion Pathway Steps ae a site assessment Phase for VAP No The vapor intrusion pathway does not need to be further addressed Is there a potential for volatile and toxic COCs in soil and or ground water See Appendix A No Document that the vapor intrusion pathway is incomplete and update id No N Document that the vapor intrusion 4 Yes Develop DQOs and CSM Based on the CSM is there a potentially complete Vapor Intrusion pathway Yes D Conduct soil ground water and or soil gas sub slab sampling as necessary update CSM pathway is incomplete Are any COCs listed in Appendix A in sampled media and update Yes N Evaluate data using modeling screening levels site specific data etc Yes 5 Contact Ohio EPA CERRY Does data evaluation indicate the possibilit
91. ied for the purposes of complying with remedial response and voluntary actions in Ohio Special thanks to the California Environmental Protection Agency Department of Toxic Substances Control for permission to use the Interim Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air December 2004 as a template In some instances exact phrasing from California s guidance was used Disclaimer This guidance was developed solely for sites in the Remedial Response Program RRP and VAP DERR Ohio EPA Use of this guidance for other Ohio EPA programs or state agencies may not be appropriate The guidance serves as an instructional tool for the investigation and evaluation of vapor intrusion at sites in Ohio It is not meant as a regulatory document and any statements provided herein are not legally binding ACRONYMS ASTM BGS BUSTR CERCLA COCs CP CSM DERR DQOs ELCR GC MS HI HQ HVAC ITRC J amp E Model NCP O amp M Ohio EPA OSWER PCBs PPBV PPM PPMV RAGS RI FS RRP RSL SARA SCIA SIM SOP U S EPA VAP VOCs American Society of Testing and Materials Below Ground Surface Bureau of Underground Storage Tank Regulations Comprehensive Environmental Response Compensation and Liability Act Chemicals of Concern Certified Professional Conceptual Site Model Division of Emergency and Remedial Response Data Quality Objectives Excess Lifetime Cancer Risk Gas Chromatograph Mass Spec
92. il gas surveys to assess the vapor intrusion pathway The Soil Gas Probe Field Data Report Form in Appendix E is useful for recording data when conducting soil gas evaluations Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 22 of 104 TABLE 2 Common Tracers Tracer Advantages Disadvantages Can check for leaks on site with Party grade helium may have low ppbv handheld detector VOC contamination If used send a Helium Can quantify amount of leakage QC sample to lab for analysis accurately Process is more cumbersome than Does not interfere in TO 15 some others analysis Cannot be analyzed by TO 15 Can be difficult to apply to sampling train connections Easy to use in identifying leaks Concentration introduced to assess leak Can be detected by VOC analytical is estimated methods Large leak may lead to VOC analysis Liquid Tracers Easier to apply to sampling train interferences connections No simple field screening method May leave residual contamination on sampling train Qualitative Can check for leaks with on site Very expensive instrument with very low detection Field instrument subject to interference limits with chlorinated solvents Sulfur Hexafluoride Cannot be analyzed by TO 15 A greenhouse gas Cost effective easy Cannot be used in an environment Ambient Air Oxygen Check for leaks
93. il subsurface soil and ground water Contaminated building materials such as concrete foundations can be a source area for a potential release to an environmental medium and should be considered e Contaminant Transport Mechanisms For each potentially contaminated medium describe the transport mechanism to indoor air usually advection and diffusion through the vadose zone and describe the characteristics of the subsurface Consider whether any preferential contaminant migration pathways such as sewer or utility lines are present Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 5 of 104 Exposure Routes Describe current buildings potential future building scenarios as appropriate and areas where vapors may accumulate Discuss any preferential contaminant migration pathways associated with the buildings such as foundation cracks voids utility ports pipes elevator shafts sumps and drain holes e Potential Receptors List all the current and potential future receptors as appropriate that could potentially contact contaminated indoor air To document current site conditions a CSM should be supported by maps subsurface cross sections site diagrams and any other property site specific details which may be pertinent such as building characteristics The narrative description should clearly describe known site conditions and
94. il gas probes with cleanout wire Figure 2 Examples of Soil Gas Sampling Probes and Well Material NJDEP 2005 Figure 3 is a schematic of a permanent soil gas probe Permanent soil gas probes should be installed when collecting soil gas samples for risk assessments Samples should be collected over an appropriate seasonal or temporal time frame in order to adequately assess the risk from soil gas Common installation methods include direct push equipment e g Geoprobe hollow stem auger and manual slide hammer see Appendix D for the standard operating procedure for advancing soil gas probes However air rotary and mud rotary methods are not recommended Temporary vapor probes also can be installed by a variety of methods The most common methods are direct push and manual slide hammer Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 17 of 104 p amr amag Ground surface elevation Flush mount or above ground protective casing if specified Cap or valve w depth of probe indicated Concrete cement if specified Coarse sand pea gravel drainage layer Bentonite granules Drilled hole Implant tubing 1 8 1 4 Teflon Nylaflow or PEEK Hydrated bentonite Sand pack Vapor implant Figure not to scale Figure 3 Permanent Soil Gas Probe Schematic These methods allow sample tubing to be placed at the desi
95. ing sampling can be minimized using SW 846 Method 5035A U S EPA 2002 U S EPA 2002 provides the minimum requirements and minimum standards to prevent loss of VOCs during sample collection and handling Specific soil collection requirements for SW 846 Method 5035A include chemical preservation in the field using multi functional sampling devices or using empty tared and labeled VOA vials with a PTFE lined septum caps Refer to the method for specific instructions Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 30 of 104 10 0 DATA EVALUATION Flowchart Step 5 Evaluate the data using modeling screening levels and or site specific data Contact Ohio EPA if there is a possibility of imminent hazard See Section 12 0 Once analytical results have been collected the data should be compared to the appropriate risk based levels or used in the base line risk assessment Ohio EPA DERR recommends a multiple lines of evidence approach when evaluating the vapor intrusion pathway Typically this multiple lines of approach starts with sampling soil or ground water within release areas and comparing concentrations to screening levels or estimating risk through modeling After initial data collection various tools can be used to evaluate whether the concentrations of volatile COCs can potentially pose an unacceptable risk to building occupants This
96. intrusion Sources of information for the preferential pathway survey may include site walkovers geo databases Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 10 of 104 construction blueprints utility maps Sanborn maps historical aerial photos interviews utility companies Bureau of Underground Storage Tanks Regulations BUSTR etc Fill materials and sand lenses or crack in clay materials may also act as a preferential pathway The preferential pathway survey can assist in developing a soil gas sampling strategy and in development of the CSM See Wisconsin s Chemical Vapor Intrusion and Residential Indoor Air Guidance and the ITRC guidance for additional information 4 4 Sample Collection and Analysis Depending on the scope of the study and the DQOs soil gas samples may be collected using gas tight syringes glass vials sorbent media canisters or Tedlar bags Gas tight syringes are appropriate only when an on site field laboratory is used and samples are analyzed immediately following sample collection Field screening and use of a mobile lab are acceptable in order to refine DQOs by conducting on site real time field analysis Prior to collecting the soil gas sample for analysis Ohio EPA DERR recommends conducting a purge test until parameters stabilize in order to determine the optimal purge volume for the location The purge
97. ion pathway The potential for a complete vapor intrusion pathway depends on factors such as existing or future land use distance between contamination and existing or proposed buildings preferential pathways and whether contaminant plumes are at steady state The DQOs and CSM are not static these components are continually refined and revised as data are collected at the site Note that DQOs and a CSM are also necessary components for any VAP Phase Property Assessment and RI FS for RRP sites If the CSM indicates that the vapor intrusion pathway is potentially complete sample soil ground water exterior soil gas and or subslab soil gas Data from only one environmental medium is generally not sufficient to fully assess the vapor intrusion exposure pathway A multiple lines of evidence approach is preferred to evaluate pathway completeness from all environmental media to assess the complete and potentially complete vapor intrusion exposure pathway to human receptors and to reduce uncertainties Evaluate the data using modeling screening levels and or site specific data Contact Ohio EPA if there is a possibility of imminent hazard A number of tools can be used at this stage to determine if the vapor intrusion pathway poses a potential unacceptable risk for building occupants This guidance allows a conservative evaluation of soils in addition to the evaluation of soil gas and ground water through the U S EPA Johnson amp Ettinger Mo
98. ions will not likely increase in the future e Site conditions at the time of soil gas sampling are not likely to result in higher soil gas concentrations due to seasonal atmospheric hydrogeologic or other reasons Due to the potential for variability in soil gas concentrations Ohio EPA DERR does not recommend the averaging of soil gas samples each data point should be evaluated separately Similarly ground water and soil data should not be Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 33 of 104 averaged unless it can be demonstrated that the exposure point concentration is protective If indoor air values are exceeded as a result of vapor intrusion remedial activities are likely necessary If subslab soil gas concentrations exceed the screening levels or applicable standards but indoor air values meet then continued monitoring or further assessment may be warranted Multiple sampling events may be necessary to rule out vapor intrusion as a pathway of concern An O amp M plan may be necessary for ongoing monitoring and or implementation of remedial activities 10 3 Identified Areas and Exposure Units An identified area or site may be relatively large while containing smaller exposure units or areas of concern As an example a ground water plume may be present beneath multiple buildings or beneath a large building Alternatively a l
99. ip and notify the lab supplier of any discrepancy or damage Familiarize yourself with the diagram located on this page and the equipment you received for sampling The flow controller regulator will be set for the appropriate sampling rate in the lab and should not require adjustment Remove the brass caps from the flow controller regulator and canister Connect the flow controller to the canister by inserting the canister connection into the canister inlet and hand tighten the Swagelok nut being careful not to cross the threads Using two open end wrenches 1 2 amp 9 16 tighten the nut no more than 1 8 turn past finger tight DO NOT use adjustable wrenches or pliers The fittings are swage lock compression fittings Do not use Teflon tape or other sealants they are not necessary DO NOT over tighten any connection Over tightening may potentially cause leaks The canister and controller are now ready for sampling If you intend to sample a source location you will need to attach a sampling line This should be 4 outer diameter tubing virgin Teflon recommended or cleaned stainless steel If possible coordinate with the lab to supply a Swagelok nut and set of nylon ferrules for connecting line Slide the nut the back ferrule then the front ferrule onto the tubing Insert the tubing into the sample inlet and slide the ferrules into the fitting Secure the nut being careful not to cross the threads No
100. lation value An Ohio EPA Division of Emergency and Remedial Response representative should be consulted to confirm whether extrapolation of an oral toxicity value to an inhalation toxicity value is appropriate Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 34 of 104 11 1 Overview of the Johnson and Ettinger Model Fate and transport models can assist in evaluating the intrusion of subsurface volatile contaminants into enclosed spaces However models are not intended to serve as the exclusive approach for evaluating human health risk due to vapor intrusion When used in combination with site specific information the results of modeling will add to the multiple lines of evidence for this exposure pathway The Johnson and Ettinger 1991 model J amp E model is one of the most commonly used models for evaluating the vapor intrusion to indoor air exposure pathway U S EPA programmed the J amp E model into Microsoft EXCEL and added a health risk component that calculates the risk from inhaling the specific chemical at the concentration estimated in indoor air Other vapor intrusion models are available and the intent of this guidance is not to exclude the use of different models to evaluate vapor intrusion to indoor air However it is recommended that the use of any other vapor intrusion to indoor air model at a site be approved by Ohio EPA DERR p
101. ldings LC Identify subslab ventilation systems or moisture barriers present on existing buildings Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 60 of 104 Source Area L Identify the COC s related to the vapor intrusion pathway L Describe the distribution and composition of any NAPL at the site L Identify on a site plan all source areas for the COC s related to the vapor intrusion pathway C Identify on a site plan soil and ground water results for the COC s between the source area and the buildings under investigation L Identify on a geologic cross section soil and ground water results including depth L Describe the potential migration characteristics e g stable increasing decreasing for the distribution of COC s Geology Hydrogeology C Review all boring logs and soil sampling data to understand the locations of e Sources NAPL soil ground water suspected vapor leaks e Soil types o Finer grained soil layers o Higher permeability layers that may facilitate vapor migration Identify on a geologic cross section distinct strata soil type and moisture content e g moist wet dry and the depth intervals between the vapor source and ground surface and include the depth to ground water _ Describe ground water characteristics e g seasonal fluctuation hydraulic gradient
102. ment whereas it is 1 E 5 for cancer risk and 1 0 for target hazard quotient for soil gas and ground water assessments Cumulative excess lifetime cancer risk and noncancer hazard are then calculated and applicable risk goals and standards are assessed within the site specific risk assessment Tables 4 and 5 indicate that the enclosed floor space length and width are assumed to be 1000 cm 82 8 feet for both the residential and commercial industrial land use scenarios These are the default values taken from the U S EPA User s Guide for Evaluating Subsurface Vapor Intrusion Into Buildings J amp E User s guidance The enclosed floor height is assumed to be 304 8 cm 10 feet Even in the case where a commercial or industrial building has a larger overall building footprint buildings are commonly subdivided into smaller work areas offices or retail establishments These smaller areas can comprise the exposure unit for the receptor population e commercial worker and need to be assessed For developed properties or those properties where the redevelopment plan is known the enclosed floor space and height input values can be property specific provided that the building dimensions used in the modeling also consider the smallest anticipated exposure unit 11 5 Use of Site Specific Soil Type and Input Parameters in the J amp E Model The authors of the J amp E model recognize that the model is sensitive to soil input parameters and p
103. mit Range and Methodology p Tenax solid sorbent 0 02 200 g m 0 01 100 TOA GC MS or GC FID i ppbv f Molecular sieve sorbent 0 2 400 ug m 0 1 200 1 CCMS vas ppbv Tedlar bag or canister BTEX MTBE 3 103 GC FID TPH 1 3 pg m TO 4A Filter media Pesticides Pesticides 0 5 1 ug sample GC ECD PCBs PCBs 1 2 ug sample Filters designed for PCB collection a TO9A High resolution GC MS Mono Di PCBs Contact lab TO 10A Filter media Pesticides Pesticides 0 5 1 ug sample GC ECD PCBs PCBs 1 2 ug sample Ane Polyurethane foam PUF TO 13A GC MS SVOCs 5 10 ug sample TO 13A SIM cal ta media Low Level SVOCs 0 5 1 ug sample Canister Tedlar bag 3 TO 14A GC ECD EID or GC MS Non polar VOCs 1 3 g m Silica lined canisters Tedlar TO14A bag sorbent media H2S Contact lab Canister Tedlar Bags VOC _ Bn A TO 15 GC MS polar nonpolar 0 4 20 g m 0 2 2 5 ppbv Silica lined canisters Tedlar TO 15 bag sorbent media H2S Contact lab Canister Tedlar bag TPH Alkanes 1019 GC FID C4 C12 Oot pully TO 15 SIM Canister Tedlar bag Low level VOCs 0 011 0 5 pg m GC MS i Sorbent tube chilled i 3 TO 17 GC MS VOCs 1 3 g m Syringe Tedlar bag Canister ae d glass vial VOC 1 60 g m GC PID 8260 A B Silica lined canisters Tedlar HS Contact lab bag sorbent media 8260B Syringe Tedlar bag Canister modified glass vial VOC 50 100 pg m eee GC MS Tedlar bag cani
104. n 7 1 1 Indoor Air conduct a building structure survey Appendix F to determine potential target receptors and_ identify potential interferences to sample collection A _ pre sampling inhabitant worker questionnaire should also be completed at this time It is important to recognize and eliminate potential interferences to the sample collection process This should be done at least 48 to 72 hours prior to sample collection Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 90 of 104 7 2 Ambient Air survey the exterior area outside the structure and or equipment Sample location should be on the windward side of the structure with the intake probe set to an appropriate representative height and without the potential for interference and or biased by vapor flux from contaminated soil surface s Discretion to avoid potential equipment theft or vandalism should also be taken into consideration when determining sample location placement 7 1 2 Sample canisters should be placed at appropriate breathing zone heights 7 1 3 Special consideration must be given to dirt basements and crawl spaces within the structures 7 1 4 Indoor Air sampling should be conducted in the lowest indoor areas or areas that are likely to capture highest concentrations Sampling Set Up 7 2 1 Document appropriate information on field log sheet Canis
105. n evaluation guidance If methane is near explosive levels in a building then the local fire department should be contacted immediately 13 0 RISK CHARACTERIZATION Flowchart Step 6 Calculate the potential risk and hazard from the vapor intrusion pathway Use of Occupational Safety and Health Administration OSHA Standards For DERR commercial and industrial sites the OSHA Permissible Exposure Limits PELs are not an appropriate standard for evaluating the risk associated with vapor intrusion to indoor air Hence for vapor intrusion potential adverse effects to humans should be evaluated in terms of acceptable exposure based on U S EPA risk assessment methodologies rather than by comparison to OSHA PEL values An exception is made for operating facilities provided that the contaminant of concern is used in site processes within the area of the building being investigated OSHA generally will take the lead role in addressing occupational exposures For releases of contaminants to soil or ground water that are the same as those used in on site processes a distinction must be made between the contribution to indoor air risk derived from the environmental media and the portion derived from on site processes A remedy is necessary if release to environmental media results in exceedance of risk or hazard goals Use of Maximum Contaminant Levels MCLs The vapor intrusion target level for ground water defaults to the MCL consistent with U S
106. nt grout that discharged out of the hole during placement avoid getting any of the concrete grout into fittings or on fitting threads Allow the cement grout to cure according to manufacturer s instructions before sampling Figure 4 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 78 of 104 7 2 Sampling Set Up 7 2 1 Wrap one layer of Teflon thread tape onto the NPI end of the male connector OR wrap one layer of Teflon tape onto the threaded end of the hose barb adapter 3 16 barb x 1 MIP 7 2 2 Carefully remove the 1 4 hex socket plug from the female connector Refer to Section 7 3 if the probe breaks loose from the anchoring cement grout during this step 7 2 3 To ensure that the subslab port has not been blocked by the collapse of the inner hole below the end of the stainless steel tubing a stainless steel rod diameter may be passed through the female connector and the stainless steel tubing The rod should pas freely to a depth greater than the length of the stainless steel tubing indicating an open space or loosely packed soil below the end of the stainless steel tubing Either condition should allow a soil gas sample to be collected If the port appears blocked the stainless steel rod may be used as a ramrod in an attempt to open the well If the well cannot be opened the probe should be reinstalled or a ne
107. ntially complete to residential receptors Subslab soil gas and indoor air collection for vapor intrusion should be conducted after a reasonable assessment from affected environmental media soil and or ground water indicates that risk goals may be exceeded Prior to conducting any direct sampling within a residential scenario the volunteer site coordinator should consider how the potentially impacted community and local government should be notified Proper community involvement efforts are critical to the effective implementation of sample collection screening and risk communication Public meetings may be necessary including a pre sampling meeting to explain results from previous sampling and a post sampling meeting to explain any findings Meetings may also be necessary to discuss additional and or follow up air sampling or the determined remedy The quality of outdoor air is important to consider in the CSM and remedy selection Thus collecting outdoor ambient vapor samples concurrently with indoor air sampling is required Additionally the indoor air sub slab sampling form found in Appendix F should be completed prior to any indoor air or subslab soil gas sampling at residential properties For further guidance on community outreach please see Appendix A Community Stakeholder Concerns in the ITRC guidance and Appendix H Community Involvement Guidance in the U S EPA OSWER 2002 guidance Sample Collection and Evaluation of Vapo
108. nts for evaluating the vapor intrusion pathway Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 3 of 104 Flowchart Step 2 Determining whether there is potential for any volatile and toxic COCs in soil or ground water at a site Appendix A The chemicals in the subsurface must be sufficiently volatile and toxic to present a vapor intrusion risk If any of the chemicals listed in Appendix A were potentially released the site should be evaluated for vapor intrusion This includes evaluating the history of adjacent properties for potential VOCs that may have affected the subject site If there is no reason to believe that a release of VOCs from Appendix A may have affected the site then the risk associated with potential vapor intrusion does not need further evaluation The chemicals in Appendix A were taken from the U S EPA Vapor Intrusion Guidance Document U S EPA 2002 with the addition of hydrogen sulfide and n hexane Monochloro and dichloro biphenyls are also listed However it may not be necessary to evaluate vapor intrusion at every site that could have a potential PCB release PCBs can be produced as byproducts of a number of chemical processes containing chlorine and hydrocarbon sources Currently U S EPA rules control the use of commercial PCB mixtures through the Toxic Substances Control Act While PCB mixtures e g Aroclors are
109. o EPA s Remedial Response and Voluntary Action Programs Page 39 of 104 Table 5 Acceptable J amp E Model Inputs for Soil Gas and Ground Water Variable Default Value Comments Restrictions Average soil ground water 11 degrees C temperature For residential structures it may be necessary to Depth below limit slab on grade or rade to bottom of 15 cm and 200 Prot tes I ATUA TACAID MN other types of g model with slab and basement ype enclosed floor cm construction as needed space unless building already exists Deed restriction necessary for commercial industrial Depth below grade to water table or soil gas Site specific sampling depth Thickness of soil Site Specific strata Soil types other than default sand can only be used with site specific geotechnical data Applies to all soil strata used in Soil Type directly Default Value above water table Sand the model Soil vapor Default values See guidance at Section 11 6 for permeability for soil type user defined values Default values from J amp E model for site specific soil type or user defined values from geotechnical data Default values Bulk density Sand Default values from J amp E model for site specific soil type or user Detank values defined values from geotechnical Total Porosity Sand data Default values from J amp E model for site specific soil type or user Soil Wargi fille
110. ollection Smoking certain hobbies and or equipment maintenance are examples of activities which may impact the ability to collect a representative sample Conducting a pre sampling on site survey and completing a written questionnaire is important to address such potential inferences Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 89 of 104 5 0 6 0 6 0 7 0 Ambient air sample location s should be pre selected with the aforementioned site selection criteria taken into consideration Equipment Apparatus Stainless steel SUMMA canister s request at least one additional canister as a backup if possible and make sure that the canisters are labeled with the decontamination information Appropriate flow regulator properly calibrated for the specified sample collection duration e g 30 minutes 8 hours 24 hours with in line particulate filters and vacuum gauges request at least one additional gauge if possible Appropriately sized open end wrench typically 9 16 inch may want two wrenches so that you can tighten the fitting in two directions at the same time Copy of building survey and resident questionnaire s PID Sample collection log Canister Sampling Data Sheet Chain of custody COC form Field notebook Digital camera Reagents N A Reagents N A Procedures 7 1 Sample Location Determinatio
111. on for use in a property specific risk assessment Remediation Mitigating Indoor Air Exposure and or Conducting Long Term Monitoring If data evaluation indicates the potential for unacceptable risk there are several remedies that may be considered to mitigate vapor intrusion to indoor air For VAP sites the volunteer selects the remedy For RRP sites the remedy is selected following procedures outlined in CERCLA as amended by SARA and the NCP and may be defined by site specific orders Potential remedies may include e Removing VOC contamination through site remediation e Installing passive or active vent systems existing buildings e Installing passive and or active vent systems membrane systems future buildings vi e Design of ventilation systems to mitigate indoor air concentrations HVAC e Institutional controls restricting structures or types of structures on contaminated property e The implementation and monitoring of appropriate engineered remedies to prevent or mitigate vapor intrusion Monitoring of engineered controls must continue until risk based clean up levels as measured in environmental media have been met For any remedy chosen for a site long term monitoring of soil gas and indoor air may be necessary under an Operations and Maintenance O amp M plan The frequency of the monitoring will depend upon site specific conditions and the degree of VOC contamination vii TABLE OF CONTENTS 10 INTRO
112. ow the requirements of the Comprehensive Environmental Response Compensation and Liability Act CERCLA as modified by the Superfund Amendments and Reauthorization Act SARA the National Contingency Plan NCP guidance outlined in the site orders e g consensual Remedial Investigation Feasibility Study RI FS unilateral and the generic or site specific statement of work There are some differences between the programs and their methods of assessment decision points and remedy selection However the approach discussed here applies to both programs unless explicitly noted Special consideration is given for potential vapor intrusion to residential structures Risk communication issues may arise if sampling and evaluation of the pathway does not follow a stepwise succession from contaminated media through soil gas to indoor air See Appendix B for considerations when evaluating vapor intrusion potential for residential properties Step Wise Approach If volatile organic compounds VOCs are present in the subsurface at a site the vapor intrusion pathway should be evaluated along with other complete or anticipated exposure pathways identified through site assessment Due to the complexity of vapor intrusion many professional disciplines may be needed to evaluate and mitigate exposure Ohio EPA DERR recommends a step wise approach as discussed below and depicted in Figure 1 for the evaluation of vapor intrusion to indoor air Figure 1 prov
113. por Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 14 of 104 the expected highest concentrations For sites that overlie contaminated ground water soil gas samples should be collected from immediately above the capillary fringe zone and half way to the surface Exterior soil gas samples may exhibit a high degree of spatial and temporal variability U S EPA 2008 According to U S EPA soil gas concentrations measured exterior to a building may not be representative of soil gas concentrations measured directly beneath the building foundation i e subslab The bias introduced by these factors may be high or low depending on climatic and building conditions and the extent to which the samples accurately represent the spatial and temporal variability of concentrations under the building Bias should be given to preferential pathways such as utilities and fill materials located at the site Ohio EPA recommends that permanent vadose monitoring points for sample collection be installed when practical to evaluate the temporal variations in soil gas concentrations Soil gas sampling should be postponed at least 24 hours after a major rain event one half inch or more and the sampling area must be free of ponded water For vertical delineation at sites without contaminated ground water soil gas samples should be collected at various depths based on the site conceptual model e g 5 fe
114. ptions about the partitioning of the contaminant into the gas phase While partitioning equations are readily available using them increases the uncertainty in evaluating vapor intrusion For existing buildings subslab soil gas concentrations best reveal the potential for vapor intrusion directly into the building The flow chart at Step 4 does not necessarily require that environmental media be sampled in a linear fashion e ground water or soil soil gas subslab soil gas indoor air However for potentially impacted residential properties the preference is to determine impacts from soil gas soil and ground water first to determine if a potential for vapor intrusion exists A more detailed discussion of the relative importance and iterative sampling of the different media is provided in Sections 4 6 4 7 and 10 1 If soil gas soil and or ground water data indicate a potential risk to building occupants then subslab soil gas and indoor air data should be collected and used in the risk evaluations Special considerations are advisable when evaluating residential properties and or imminent threat situations and are discussed in Appendix B and Section 12 respectively Although measuring indoor air concentration is a direct measurement at the exposure point many factors including materials used or stored indoors disturbance of sampling equipment during testing and the possibility of ventilating the building during the sample event i e
115. r trades people accessing crawl space Subslab rae a gt ie to high e Higher energy costs and less effective than SSD pressurization fone ie soils gay e Potential for short circuiting through cracks e Large commercial structures e Requires regular air balancing and maintenance Building new or existing e May not maintain positive pressure when pressurization e Specialized cases only building is unoccupied e Typically generates a waste disposal stream iidoor air e Effective capture of air contaminants may be difficult voatnart e Specialized cases only e Energy intensive with significant operation maintenance and monitoring burden Sealing the e Cracks and holes in existing e Access to perforations building envelope building e Permanence Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 50 of 104 15 0 REFERENCES American Petroleum Institute November 2005 A Practical Strategy for Assessing the Subsurface Vapor to Indoor Air Migration Pathway at Petroleum Hydrocarbon Sites Publication Number 4741 American Society for Testing and Materials 2005 Standard Practice for Environmental Site Assessments Site assessment Environmental Site Assessment Process ASTME1527 05 American Society for Testing and Materials 2006 Standard Test Method for Measurement of Pneumatic Permeability of Partially Saturated Porou
116. r Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 31 of 104 The following default attenuation factors AF or a are recommended in this guidance Cindoor air a 0 1 Coil gas Cindoor air a 0 001 Cground water The default attenuation factors assume the following conditions for their use in evaluating an existing or future building The subsurface is reasonably homogeneous uniform e No fractures exist in the subsurface Ground water is greater than 10 feet below surface grade Fluctuations of the ground water surface are minimal e Non aqueous phase liquid NAPL is not present on the water table e Preferential pathways do not exist Biodegradation of vapors is not occurring Contaminants are homogeneously distributed e Contaminant vapors enter a building primarily through cracks in the foundation and walls e Building ventilation rates and the indoor outdoor pressure differentials are constant e Model assumptions are representative of site conditions If the above conditions do not exist the default attenuation factors should not be used Instead Ohio EPA recommends either developing site specific attenuation factors or iteratively sampling multiple media For VAP properties some of the screening values listed in the 2002 OSWER guidance must be recalculated using toxicity data listed in the VAP Program Chemical Information Database and Applica
117. r Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 59 of 104 APPENDIX C Vapor Intrusion Conceptual Site Model Checklist Utilities and Process Piping LC Identify on a site plan all underground utilities near the soil or ground water impacts pay particular attention to utilities that connect impacted areas to occupied buildings L Identify on a site plan all underground process piping near the soil or ground water impacts Buildings L Identify on a site plan all existing and future buildings under investigation L Identify the occupancy and use of each building e g residential commercial _ Describe building construction materials e g wood frame block openings e g windows doors and height e g one story two story multiple story identify if there is an elevator shaft in the building _ Describe building foundation construction including e Type e g basement crawl space slab on grade e Floor construction e g concrete dirt e Depth below grade LC Describe the building HVAC system including e Furnace air conditioning type g forced air radiant e Furnace air conditioning location e g basement crawl space utility closet attic roof e Source of return air e g inside air outside air combination e System design considerations relating to indoor air pressure e g positive pressure is often the case for commercial bui
118. rbed soil samples may be performed using the procedures outlined in ASTM D6539 00 to directly measure Kv in representative soil samples obtained from within the migration pathway between the vapor source and the receptor To use a site specific Kv parameter in lieu of default values in a given soil layer the input parameter s must be measured or estimated at no less than three 3 locations in that soil layer Depending on the volume of soil being evaluated additional locations may be warranted If taking the minimum required samples the value of Kv used in the J amp E model should be the site specific value which results in the most conservative estimate of risk The selected value should fall within the practical range of values for that parameter as presented in Table 7 of the J amp E Users Guide If the selected value does not fall within this range the modeler should provide sufficient justification for the use of the selected value To use a Statistical representation such as a mean value of Kv in lieu of default values in a given soil layer the input parameter s should be measured or estimated at no less than eight 8 locations excluding any outliers in that soil layer Depending on the volume of soil being evaluated additional locations may be warranted If taking sufficient samples to perform a valid statistical evaluation of the data the value of the soil input parameter used in the J amp E model for a soil layer may be a site spe
119. red depth for sampling then removed once a sample is collected Temporary vapor probes use a retractable or removable drive tip Typically 1 4 nylon Teflon or Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 18 of 104 polyethylene tubing is used to collect subsurface vapors for sampling in temporary applications Ohio EPA uses Geoprobe methodology for soil gas sampling however there are other direct push manufacturers such as Strataprobe and AMS Permanent soil gas probes typically consist of a screen or sample port installed at the tip of the tubing Stainless steel Teflon or nylon tubing are preferred in permanent applications Tubing selections should be based upon duration of sampling type of COCs and how long the sampling point needs to remain See Appendix G for comparison of sample tubing type to vapor absorption The soil gas probe is installed to a specific depth in a bore hole created with a slide hammer direct push system or a hollow stem auger Sand is placed in the annulus around the sampling port screen and the remainder of the bore hole is sealed with hydrated bentonite The tubing is usually labeled and capped at the surface The bore hole is completed with a protective cover at the surface Refer to Figure 3 for details 4 7 Subslab Soil Gas Sampling Subslab soil gas data which is collected from under the foundation
120. reening values either OSWER 2002 or the RSLs serve as thresholds to evaluate whether the vapor intrusion pathway is complete or whether further evaluation including evaluating the pathway in the baseline human health risk assessment is warranted The data evaluated in this step may come from ground water soil gas subslab soil gas and or indoor air However scrutiny will be applied to risk decisions made for ground water or soil gas where the models are significantly manipulated In such cases the Ohio EPA reviewer may require further evaluation of media closer to the receptor As an example if the calculated risk from ground water data alone is below values derived through application of default attenuation factors or is below target risk using conservative or reasonable property specific assumptions in the J amp E model then further evaluation of the VI pathway through soil gas and indoor air will likely not be necessary However if concentrations of ground water are at or near risk goals with significant manipulation of model inputs and or use of site specific attenuation factors or NAPL is present then further sampling of the site including soil gas subslab gas sampling or indoor air monitoring may be required Please refer to U S EPA Risk Assessment Guidance for Superfund Part F 2009 to evaluate inhalation exposures Flowchart Step 7 If data evaluation indicates risk or hazard goals are or may be exceeded then additional
121. rior to its use The J amp E model is a simple deterministic model having single point inputs and outputs and is based on the basic principles of contaminant fate and transport contaminant partitioning between media and the physical and chemical properties of the contaminants themselves The model incorporates both diffusion and advection as mechanisms of transport of subsurface vapor into the indoor air environment For the J amp E model diffusion is the dominant mechanism for vapor transport within the vadose zone Once the vapor enters into the building zone of influence the vapors enter into the building through foundation cracks by advection due to the indoor outdoor building pressure differential The distance of the building zone of influence i e the advection zone is usually less than a few feet The J amp E model uses the conservation of mass principle and is based on the following assumptions Steady state conditions exist An infinite source of contamination exists for the ground water and soil gas models The subsurface is homogeneous Air mixing in the building or enclosed space area is uniform Preferential pathways do not exist Biodegradation of vapors does not occur Contaminants are homogeneously distributed Contaminant vapors enter a building primarily through cracks in the foundation and walls Buildings are constructed on slabs or with basements Sample Collection and Evaluation of Vapor Intr
122. s Materials by Flowing Air ASTM D6539 00 2006 American Society for Testing and Materials 2008 Standard Guide for Developing Conceptual Site Models for Contaminated Sites ASTM E1689 95 2008 California Environmental Protection Agency Department of Toxic Substance Control CAL EPA DTSC December 15 2004 Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air Colorado Department of Public Health and Environment Hazardous Materials and Waste Management Division September 2004 Indoor Air Guidance Davis B K J F Beach M J Wade A K Klein and K Hoch 2002 Risk Assessment of Polychlorinated Biphenyls PCBs in Indoor Air The Toxicologist Supplement to Toxicological Sciences 66 106 Abstract Number 516 DeVaull G E R A Ettinger J P Salanitro and J B Gustafson 1997 Benzene toluene ethylbenzene and xylenes BTEX degradation in vadose zone soils during vapor transport First order rate constants Proceedings of the petroleum hydrocarbons and organic chemicals in ground water conference Prevention detection and remediation November 12 14 1997 Houston TX Ground Water Publishing Company Westerville Ohio 365 379 Fitzpatrick Nancy A and John J Fitzgerald October 1996 An Evaluation of Vapor Intrusion into Buildings through a Study of Field Data Massachusetts Department of Environmental Protection Folkes D J Design Effectiveness and Reliability of Su
123. se sampler on holding times and any method specific requirements The indicated methods use a sorbent based sampling technique The detection limits will depend on the amount of air passed through the media Reporting limits are compound specific and can depend upon the sample collection and the nature of the sample Detection limits shown are for the range of compounds Consult laboratory for specific information ECD electron capture detection FID flame ionization detection GS gas chromatography MS mass spectrometry PID Photoionization detection TCE thermal conductivity detection High volume collection may require large sample volume e g 300 m chilled 4 C 4 6 Exterior Soil Gas The CSM including soil stratigraphy depth to ground water and permeable zones should be used to determine appropriate sampling depths In most situations it will be necessary to install probes at multiple depths at one location nested to evaluate the vertical distribution of contaminants in soil gas For commercial properties with buildings soil gas samples should be taken under the building e subslab sampling due to the potential for vapor accumulation under the foundation If this is not practical then the samples should be collected as close to the building as possible Soil gas samples should be collected based on the CSM with the sampling locations depths biased toward Sample Collection and Evaluation of Va
124. sed April 1994 U S EPA October 1993 Radon Reduction Techniques for Existing Detached Houses Technical Guidance for Active Soil Depressurization Systems 37 Edition EPA 625 R 93 011 U S EPA January 1999 Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air Second Edition EPA 625 R 96 01 Ob U S EPA 2001 Building Assessment Survey and Evaluation BASE Database Washington DC Office of Air and Radiation U S EPA April 2001 Building Radon Out A step by step Guide on How to Build Radon Resistant Homes EPA 402 K 01 002 U S EPA November 2002 OSWER Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Ground water and Soils Subsurface Vapor Intrusion Guidance Draft U S EPA 2006 Guidance on Systematic Planning Using the Data Quality Objectives Process Office of Environmental Information Washington D C EPA 240 B 06 001 Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 54 of 104 U S EPA March 2008 Brownfields Technology Primer Vapor Intrusion Considerations for Redevelopment Office of Solid Waste and Emergency Response EPA 542 R 08 001 U S EPA March 2008 DRAFT U S EPA s Vapor Intrusion Database Preliminary Evaluation of Attenuation Factors Office of Solid Waste and Emergency Response U S EPA October 2008
125. sis Upon receipt at the laboratory the data documented on the canister tag is recorded Sample holding times are compound dependent consult with the laboratory for holding times Refer to Ohio EPA SOP 2 5 3 for details on sampling using a Summa Canister 3 2 Tedlar Bag Sampling Tedlar bags most commonly used for sampling gas have a 1 liter volume capacity Typically Tedlar bags are filled using a lung box After sampling the Tedlar bags are stored in a clean cooler without ice a cardboard box or an opaque plastic bag at ambient temperature to prevent photodegradation It is essential that sample analysis be undertaken within 24 to 48 hours following sample collection since VOC s may escape or become altered Refer to Ohio EPA SOP 2 5 1 Section 5 1 1 Sample Preparation and Collection using a Lung Box for more details Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 75 of 104 4 0 5 0 Interferences and Potential Problems The thickness of a concrete slab will vary from structure to structure A structure may also have a single slab where the thickness varies A slab may contain steel reinforcement e g rebar Drill bits of various sizes and cutting ability may be required to penetrate slabs of varying thicknesses or those that are steel reinforced Ensure that all subslab utilities public and building specific ha
126. slab and is within the advective envelope of the building driven depressurization indicate whether contaminants have accumulated directly under the building see Appendix D for example SOPs Analytical detection limits should be low enough to effectively evaluate the indoor air risk See Section 10 for more information on calculating risk levels Subslab soil gas sampling may shorten the timeframe for evaluation of the exposure pathway and may help reduce the overall cost of a vapor intrusion evaluation When proceeding directly to subslab soil gas sampling further characterization of the subsurface soil gas around the building determination of the physical character of the vadose zone through geotechnical testing and site specific vapor intrusion modeling may not be needed However the collection of subslab soil gas samples can be inconvenient to building occupants since it requires the removal of floor coverings and coring or drilling of the foundation slab If chemicals are detected in subslab soil gas installation of permanent sampling ports may be necessary to determine the temporal variability of the data When subslab soil gas sampling is conducted an appropriate number of samples should be taken to characterize the subslab area The number type time integrated or grab samples and locations of subslab soil gas samples should be determined based on information collected during the building survey an understanding of the building foun
127. state what assumptions were made to generate the CSM The narrative should include a description of ambient sources and the presence of nearby potential sources of VOCs such as neighboring dry cleaning operations As additional data are collected and analyzed through the evaluation of the vapor intrusion pathway the CSM should be updated The CSM is an essential decision making and communication tool for all interested parties Additional information on the development of a CSM can be found in guidance published by U S EPA Risk Assessment Guidance for Superfund RAGS Part A 1989 Standard Guide for Developing Conceptual Site Models for Contaminated Sites ASTM E1689 95 2008 DERR guidance and or U S EPA DQO guidance The CSM may conclude that the vapor intrusion pathway is incomplete However if the CSM indicates the possibility of a complete exposure pathway for vapor intrusion proceed with Step 4 in Figure 1 e collect samples from environmental media on the site For RRP sites the CSM cannot be used to eliminate the vapor intrusion pathway without sampling potentially affected environmental media For VAP properties a demonstration that the vapor intrusion pathway is incomplete or is effectively mitigated can be made if any of the following apply e The current and proposed land use is known and does not include occupied structures e A pre emptive remedy is in place to mitigate vapor intrusion Such systems may include
128. ster TPH alkanes F ened GCMs C4 C12 1 ppmv Tedlar bag Canister 1000 g m 20 000 ppbv to 8270C GC MS SVOC 100 000 ppbv m Tedlar bag canister TPH alkanes 8015 modified GC FID C4 C24 10 ppmv Inductively Coupled Plasma Mass 7471A Spectrometry ICP MS Hg Contact lab Gold trap Air Toxics lO 5 Dual amalgamation Hg Contact lab Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 13 of 104 TABLE 1 Comparison of Soil Gas Analytical Methods Examples of Collection Method No Device Peel Leche ds Reporting Limit Range and Methodology p cold vapor atomic fluorescence spectrometry CVAFS Hopcalite NIOSH 6009 cold vapor Atomic Absorption Hg Contact lab CV AA 9056 Silica lined canisters Tedlar Bag HS Contact lab sorbent media Filters designed for PCB 1668A collection Mono Di PCBs Contact lab High resolution GC MS Methane 10 ppmv Tedlar bag Canister U S EPA 3C nitrogen oxygen GC FID carbon dioxide 0 1 1 000 ppmv carbon monoxide p Methane i Tedlar bag canister nitrogen oxygen 2 3 ASTM D21946 GC TCD FID carbon dioxide 1000 2000 pg m 7 carbon monoxide ASTM D 1945 emer pag canister Natural gases 1000 2000 ug m GC FID NOTE the laboratory should be consulted prior to choosing the analytical method The laboratory can advi
129. te when using nylon ferrules a snug finger tight should be sufficient for a leak free connection To begin sampling open the canister valve by turning counter clockwise One full turn is sufficient Observe and note the vacuum gauge reading on your field log form Take photos of the sample location and close up of the properly functioning sampling equipment Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 94 of 104 8 Observe the decline in the vacuum to gauge the sampling rate This is especially significant for grab samples In a one hour sample duration the gauge should drop in vacuum at a rate of 0 5 Hg per minute i e 30 60 min Note that is condition is a rough estimate and may not necessarily be reflective of your particular equipment Sampling rate s are established before sampling and are set by the laboratory supplying the equipment Contact the lab immediately for assistance if your equipment demonstrates any malfunctioning As a consequence for the potential for a malfunction it is advisable to request one or two back up additional canisters and flow regulators when coordinating with the lab 9 After sampling is complete note the time and final vacuum gauge reading on your field log sheet Close the canister valve by turning clockwise until finger tight DO NOT over tighten as this will damage the valve 10 Disassemble
130. ter Sampling Data Sheet 7 2 2 Remove brass plug from the SUMMA canister and connect the flow regulator with in line particulate filter and vacuum gauge to the SUMMA canister Use the open end 9 16 wrench to gently tighten the connection between the flow regulator and the canister Do not over tighten this connection Do not open the valve on the SUMMA canister if one is present Record both the SUMMA canister number and the flow regulator number on the Canister Sampling Data Sheet The canister number can be used for sample identification on the COC form refer to Attachment 1 Sampling Instructions for Canisters with Pneumatic Flow Controllers 7 2 3 Open the canister regulator valve Record the sample start time and the canister pressure 7 2 4 Take a photograph of the canister and surrounding area Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 91 of 104 7 3 Termination of Sample Collection 7 3 1 7 3 2 7 3 3 7 3 4 Arrive at the sample location approximately 10 to 15 minutes prior to the end of the sampling interval An examination of the flow regulator should show a slight vacuum left on the gauge preferably between 2 to 10 inches of Hg on the regulator flow dial Document this final vacuum pressure and stop sample collection by closing the flow regulator valve SUMMA canister with flo
131. the canister and the canister is transported to a laboratory under chain of custody for analysis Upon receipt at the laboratory the data documented on the canister tag is recorded Sample holding times are compound dependent consult with the laboratory for holding times Interferences and Potential Problems Sampling personnel should not handle hazardous substances such as gasoline permanent marking pens wear apply fragrances or smoke cigarettes cigars before and or during the sampling event Care should be taken to ensure that the flow regulator is pre calibrated to the proper sample collection time confirm with laboratory Correctly connecting the flow regulator to the sample canister is vital to eliminate the potential for leaks Sample integrity is maintained if the sampling time is slightly shorter than the planned sampling time In other words if the SUMMA canister is allowed to completely fill such that there is no pressure vacuum left in the canister then it may be very difficult for the laboratory technician to extract a sample aliquot for analysis Sample integrity can also be compromised if the sample event is extended to a point where the canister reaches atmospheric pressure Certain activities within the building s structure s can interfere with the collection of a representative indoor air sample For example storage of paints varnish adhesives gasoline and or oils may create false positive results during sample c
132. there any odors If so describe the odors Where are the release odors found Sampling Information Sampling Date Sampler Type Sorbent Canister Tedlar Other Please circle one Analysis Method Consulting Firm Contact Person Telephone No __ Laboratory Name Telephone No Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 100 of 104 Table 1 Sorbent Tube Sample Information DF E Faine Volume Duration ID liters minutes Comments Table 2 Canister Sample Information Pressure On i Initial On site Followin ressure San Oe Floor Room cael site Sample Received at the Pressure Laboratory Collection Indicate pressure in units of inches of mercury Please provide a sketch of area and location of sampler unit s include all pertinent structures Pre Sampling Inspection and Product Inventory List products or items which may be considered potential sources of VOCs such as paint cans gasoline cans gasoline powered equipment cleaning solvents furniture polish moth balls fuel tank woodstove fireplace etc Date and time of pre sampling inspection Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 101 of 104 Table 3 Pre sampling Inspection Product Inventory Field 7 Potential VOC Present Loc
133. tion Programs Page 68 of 104 4 2 7 4 2 8 4 2 9 4 2 10 4 2 12 Pour sand down the inside diameter of the probe rods around the outside of the tubing so that the sand extends several inches above the implant Use the tubing to stir the sands into place around the implant Do not lift up on the tubing It should take less than 150 mL of sand to fill the space around the implant The sand therefore will act as a grout barrier inhibiting the grout from impacting the implant NOTE Implants come in various sizes and the drive rods can vary in diameter so it is best to calculate the necessary volume of sand for each implant installation Placement of the grout barrier by backfilling through the rods with sand can only be performed in the vadose zone not below the water table Lift the probe rods up an additional 18 24 inches and pour the bentonite granules granules into place as in Step 4 2 7 The volume to be filled is about 154 mL per foot It may be necessary to chase the seal mixture with distilled water to initiate a seal This results in a tight seal preventing gas migration down the column After the probe rods have been removed cut the tubing to a manageable length attach a 3 way valve connector or air tight e g Swagelok plug and mark the location with a pin flag or stake Attach a piece of tape to the tubing indicating the depth at which the implant was set for future reference when sampling At this
134. tions see Table 3 Samples should be collected from the lowest level of the structure where vapors are expected to enter including basements crawl spaces and where preferential pathways have been identified An outdoor location representative of background outdoor ambient air should also be collected for comparison Ohio EPA DERR recommends that indoor air samples be collected concurrent with subslab soil gas samples when appropriate for a better understanding of the vapor intrusion conceptual model at a site Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 25 of 104 TABLE 3 Comparison of Indoor Air and Subslab Soil Gas Sampling Conditions Parameter Most desirable Least desirable Season Late winter early spring Summer Indoors 10 F greater than Indoor temperature less than outdoor Temperature outdoors Wind Steady greater than 5 mph Calm Saturated with rain 1 2 of rain or Soil more within 24 hours Dry Doors Windows Closed Open Mechanical Heating System Operating Off Mechanical fans Off On Modified from Massachusetts Indoor Air Sampling and Evaluation Guide 2002 Note Sampling under the conditions specified above is the ideal however it is acknowledged that it may be very difficult to sample when the most desirable conditions are present for all circumstances The sampler must make a
135. trometer Hazard Index Hazard Quotient Heating Ventilation and Air Conditioning Interstate Technology Resource Council Johnson and Ettinger Vapor Intrusion Model National Contingency Plan Operation and Maintenance Ohio Environmental Protection Agency Office of Solid Waste and Emergency Response U S EPA Polychlorinated Biphenyls Parts per Billion Volume Parts per Million Parts per Million Volume Risk Assessment Guidance for Superfund Remedial Investigation Feasibility Study Remedial Response Program Regional Screening Level Superfund Amendments and Reauthorization Act Source Control Interim Action Selected lon Monitoring Standard Operating Procedure United States Environmental Protection Agency Voluntary Action Program Volatile Organic Compounds includes all compounds listed in Appendix A EXECUTIVE SUMMARY The intrusion of subsurface vapors into buildings is one of many exposure pathways that must be considered in assessing human health risk posed by releases of hazardous substances and petroleum In this document the Ohio EPA DERR recommends a stepwise approach and sampling methodologies for evaluating vapor intrusion DERR currently administers two clean up programs The VAP is semi privatized site assessments and clean ups are conducted by VAP CPs The VAP operates under Ohio Revised Code ORC 3746 and Ohio Administrative Code OAC 3745 Site clean ups under the RRP are directed by Ohio EPA staff and foll
136. usion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 35 of 104 e Ventilation rates and pressure differences are assumed to remain constant The J amp E model is most robust under homogeneous site conditions with uniform building construction features Conversely the model is weakest under variable conditions Using a range of potential input parameters the model can predict a wide range of indoor air impacts spanning over several orders of magnitude Thus when using the J amp E model the input parameters for a site must be appropriately conservative and match site specific conditions It is important to understand the sensitivity of the input parameters on the results of the model and it is recommended that all vapor intrusion evaluations include a sensitivity analysis Vapor intrusion can be modeled using site specific inputs for soil type building parameters and exposure However the model does not use an exposure time and assumes a 24 hour exposure Please see US EPA RAGS F for guidance on exposure times for inhalation exposure scenarios According to Johnson 2002 an important step in evaluating the reasonableness of the J amp E modeling results for residential settings is to ensure that the ratio of Qsoi Qsg is between 0 01 and 0 0001 where Qgoi is the pressure driven soil gas flow rate from the subsurface into the enclosed space and Qeg is the enclosed space volumetric air flow rate
137. vapor barriers or passive or active venting systems An engineered system used to mitigate the vapor intrusion pathway requires an O amp M plan and agreement Please see OAC 3745 300 11 for more information For sites being evaluated through an RI FS or other RRP framework a vapor mitigation system may be required until such time as the remedy is selected by Ohio EPA and completed for the site Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 6 of 104 e The existing or future buildings at a site are greater than 100 feet away laterally from subsurface contamination provided there are no preferential pathways e g sewer lines that can be a direct conduit from a vapor source to a building If buildings are not located near i e within 100 feet areas of concern vapor intrusion is not likely and no further consideration of the exposure pathway should be needed Evaluations of building distance from contamination should only be conducted if the movement of subsurface contamination has reached steady state conditions e when the maximum migration potential of the subsurface plumes has been reached For ground water the migration potential can be evaluated with data from routine sampling of ground water monitoring wells If COCs in ground water indicate stable or decreasing contaminant trends the maximum contaminant migration for ground water h
138. vapor intrusion assessment The analytical method used should be able to identify and quantify the target analytes and be capable of meeting program specific requirements Soil gas sample results submitted to Ohio EPA DERR should be reported in units of ppbv and or g m Soil gas sampling field data should be recorded on the Soil Gas Probe Field Data Report Form Appendix E and submitted with the results 4 5 Analytical Detection Limits Analytical detection or reporting limits for soil gas samples should be sufficiently low to adequately evaluate the vapor intrusion pathway per project s DQOs For VAP sites an estimate of the applicable standard adjusted for the presence of multiple chemicals provides the basis for the minimum detection limits For screening at RRP sites the minimum detection limit is determined by the appropriate screening value In general application of the generic attenuation factors can be used as a basis for developing the minimum analytical detection limits in media Table 1 provides a list of several soil gas analytical methods and reporting limit ranges Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 12 of 104 TABLE 1 Comparison of Soil Gas Analytical Methods Examples of Collection Tupe of Method No Device Peedi rh dz Reporting Li
139. ve been located and marked prior to installation Equipment Apparatus Hammer drill or Rotary Hammer Alternating current AC extension cord AC generator if AC power is not available on site Hammer or Rotary Hammer drill bit diameter Hammer or Rotary Hammer drill bit 1 diameter Portable vacuum cleaner 1 open end wrench or 1 medium adjustable wrench 2 9 16 open end wrench or 2 small adjustable wrenches Hex head wrench Tubing or pipe cutter Disposable cups 5 ounce oz Disposable mixing implement e popsicle stick tongue depressor etc Swagelok SS 400 7 4 Female Connector 1 4 National Pipe Thread NPT to 1 4 Swagelok connector Swagelok SS 400 1 4 Male Connector NPT to 1 4 Swagelok connector Hose barb adapter brass 3 16 barb x 14 MIP Male Iron Pipe Ys NPT flush mount hex socket plug Ys outer diameter OD stainless steel tubing pre cleaned instrument grade Teflon washer ID 14 OD 3 14 OD Teflon tubing Teflon thread tape Ys OD stainless steel rod 12 to 24 length Swagelok Tee optional SS 400 3 4TMT or SS 400 3 4TTM Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 76 of 104 6 0 7 0 Reagents Anchoring cement grout quick setting contaminant free Tap water for mixing anchoring cement grout
140. ves of the study e Identify the chemicals of concern including parent and breakdown products e Determine physical site characteristics e g soil type depth to ground water water table fluctuations building construction etc e Identify possible preferential pathways e Determine land use building characteristics and potential receptor population e Determine if vertical profiles are needed to assess potential biodegradation attenuation e Establish soil gas probe installation and sampling protocols e Establish the number location and analytical method for soil gas samples to satisfy the plan objective including appropriate QA QC protocols such as leak testing sample duplicates detection limits and limitations and equipment blanks 4 3 Preferential Pathway Survey A survey should be conducted to evaluate potential preferential vapor migration pathways Underground utility lines can be important preferential migration pathways for vapors and can allow contaminants to migrate significant distances from source areas The survey should evaluate underground utilities such as water sewer gas electric and telecommunication lines In areas where radon gas is common a radon detection meter may provide a means to evaluate where vapors are entering a structure Subslab or indoor air sampling locations can be biased to areas where radon gas is detected However please note that the absence of radon gas does not preclude vapor
141. vide a conceptual understanding of the potential for exposure to hazardous contaminants at a site based on the sources of contamination the release mechanisms the transport media the exposure pathways and the potential receptors The CSM should include a diagrammatic or schematic presentation that relates the source of contamination to human and ecological receptors and identifies all potential sources of contamination the potentially contaminated media and exposure pathways The CSM organizes and communicates information about the site characteristics and is a necessary component of any health risk assessment However the CSM should not be considered static As the vapor intrusion investigation progresses the CSM will be updated as more information becomes available Ohio EPA recommends that the following items be included in a CSM for the vapor intrusion pathway However in the early stages of investigation not all components listed will be necessary e Primary Sources of Contamination For each potential contaminant source describe what potentially caused the contamination and provide a list of chemicals released into the environment Primary Release Mechanism For each potential contaminant source describe the means by which the release or suspected release is thought to have occurred e Secondary Sources of Contamination Include all the environmental media potentially contaminated by the primary sources such as surface so
142. w probe installed in an alternate location 7 2 4 Screw and tighten the Teflon taped male connector into the female connector OR screw and tighten the hose barb adapter 3 16 barb x MIP into the female connector Do not over tighten This may cause the probe assembly to break loose from the anchoring cement grout during this step or when the male connector hose barb adapter is removed upon completion of the sampling event Figure 5 Refer to Section 7 3 if the probe breaks loose from the anchoring compound during this step 7 2 5 If a co located subslab soil gas sample or split sample is desired a stainless steel Swagelok tee may be used in place of the male connector Figure 6 7 2 6 Attach a length of 1 4 Teflon tubing to the sampling container 9 SUMMA canister or system e g lung box for Tedlar bag to be used for sample collection Connect the other end of the Teflon tubing to the male connector with a Swagelok nut or connect to the barbed hose adapter Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 79 of 104 7 3 SUMMA canister connected to port and ready for sampling 7 2 7 After sample collection remove the male connector or barbed hose adapter from the probe assembly and reinstall the 1 4 hex socket plug Do not over tighten the hex socket plug If excessive force is required to remov
143. w regulator attached and placed at appropriate breathing zone height ready for sampling Complete the documentation by recording the stop time on the Canister Sampling Data Sheet as well as any additional field logs Remove the flow regulator from the SUMMA canister using the 9 16 open end wrench Place the flow regulator into the proper shipping container provided by the lab Re install the brass plug on the canister fitting and tighten with the open ended wrench Package the canister and the flow regulator into the shipping container provided by the lab Note the SUMMA canister does not require preservation Sample Collection and Evaluation of Vapor Intrusion to Indoor Air Guidance for Ohio EPA s Remedial Response and Voluntary Action Programs Page 92 of 104 8 0 9 0 7 3 5 Complete the appropriate forms and sample labels as directed by the laboratory Use the sample start time when completing the laboratory COC and double check canister identification numbers for accuracy 7 3 6 Ship the canisters to the laboratory for analysis Quality Assurance Quality Control Most ambient and indoor air sample analysis will be performed using U S EPA TO 15 methodology Canisters used for sample collection are typically 6 liters and thoroughly cleaned by the laboratory prior to use Flow regulators will also be thoroughly cleaned by the laboratory An additional co located indoor air sample is recommended at a frequency of 10 1 in
144. y of an imminent hazard No Include incremental risk from VI pathway VAP If COCs 6 meet screening levels then vapor intrusion pathway is incomplete RRP No Does data evaluation indicate risk or hazard goals or applicable standards may be exceeded Yes Collect more data soil gas sub slab indoor air and return to step 5 or include vapor intrusion pathway in baseline risk assessment 7 RRP or conduct a remedy VAP Remedy Step 1 Step 2 Step 3 Step 4 Step 5 Conduct a Site Assessment Phase for VAP The site assessment is paramount to determining whether the potential for the vapor intrusion pathway exists at a site Generally a site assessment involves examining the site history for release or potential release of hazardous substances or petroleum to environmental media at a site A site walkover inspection is also necessary Determine if there is the potential for any volatile and toxic chemicals of concern COCs in soil or ground water Appendix A Compare potentially released COCs identified through the Site assessment to those listed in Appendix A The COCs listed in Appendix A were determined to be sufficiently toxic and volatile to warrant an evaluation of the vapor intrusion pathway If there is a potential release of any COCs listed in Appendix A develop a Conceptual Site Model CSM and Data Quality Objectives DQOs for evaluating the vapor intrus

Download Pdf Manuals

Related Search

Related Contents

POWER NETWORK PARAMETER METER  Installation & Operation Manual  KXTD612 Installation Manual  Attuatori multigiro SA(R) 07.1 - SA(R)  User Manual - Solar Info  FST 3 - Model Library - Plant Production Systems  MODE D`EMPLOI et CONSIGNES de SECURITÉ BIO  LG F1422TD washing machine  3Dgence One  Software MultiVision2 User Manual - TS  

Copyright © All rights reserved. Failed to retrieve file