Example Application of the GENEEC Model
Contents
1. R A RUN NUMBER TO CONTIN ER CROP NAME ENT OF THE gt Cotton ER AN OUTPUT FILE E gt Cottonl EMICAL NAME gt Chlorpyrifos PROGRAM ASSUMES THAT R UNOFF IS SUFFICI DISSOLVED P ESTICIDE FROM THE E FOLLOWING INFORMATION SHOULD BE EN FROM RRE NT ACCEPT EASE ENT ER AP ER OF APPLICATIONS P ED LABEL FOR THE USE E IN QU TH E MOST ESTION PLICATION RATE IN DS a i R AC E gt 1 340 EAR gt 2 EN APPLICATIONS DAYS gt E DISSOLVED PESTICIDE CONCENTRATION IS REDUCED BY SORPTION OF THE PESTICIDE TO SOIL OR TO ORGANIC MATT E ADSORBED FRACTION IS ESTIMATED BY THE SOIL WATER UILIBRIUM PARTITION COEFFICIENT Kd ER Kd VALUE WITHOUT COMMAS gt 115 E DISSOLVED PESTICIDE CONCENTRATION IS ALSO REDUCED DEGREDATION IN THE FIELD PRIOR TO A RAINFALL RUNOFF ENT THE PROGRAM ASSUMES DEGRADATION BX AEROBIC ETABOLISM FOR TWO DAYS AFTER THE FINAL APPLICATION2. IF STABLE EROBIC METABOLISM OR 1F DATA 15 UNAVAILABLE FASE ENTER ZERO 0 ER SOIL AEROBIC METABOLIC HALFLIFE IN DAYS gt 30 5 PESTICIDE QUIRE THAT THE PESTICIDE BE ED IN EITHE RAINFALL OR IRRIGATION HIS CASE RUNOFF TO THE POND IS ASSUMED TO OCCUR DIATELY RATHER THAN AFTER TWO DAYS HIS PESTICIDE TO BE WETTED IN 2 York NY gt AN DISSOLVED PESTICIDE CONCENTRATION MAY BE DIRECT DEPOSITION OF SPRAY DRIFT INTO TH RA B or C TO SE ETHOD OF APPLICATION ERIAL SPRAY ROUND SPRAY RANULAR NON SPRAY gt A SPRAY DRIFT TO TH LOCAT TWEEN T UFE ED B Di PLEASE ENT ER THE DTH OF THE SPRAY DRIFT BUFE ER ZONE ER BODY FOR NO BUFFER B DISSOLVE DY CANNOT ER Z ERO 0 49 2 ESTICIDE Di CONCENTRATION IN A WATER F ED THE SOLUBILITV OF THE CHEMICAL SOLUBILITY IN PPM gt 1 2 RONIC G EN ERIC EC VALU ES ARE E RAT
3. ENT ER ANY O ES OF THE R ALL OF THE PLEASE ENT ER ZERO O OR WHIC RUN No H VALU EROBIC AQUATIC M ER PHOTOLVSIS ES ARE FOR ANY UNAVAILABLE ETABOLIC HALFLIFE CALCULATED BY SUMMING AQUATIC DEGRADATION PATHWAYS FOLLOWING WHICH ARE WHICH ARE STABL E OR DAYS gt 1 FOR Chlorpyrifos HALFLIFE gt 0 DAYS ON Cotton 9 INPUT VALU AVAILABLE RATI ONI AC MULT APPLICATIONS NO INTI SOIL Kd SOLUBILITY ERVAL PPM BUFFI ER FT D RIFT D INCORP EPTH IN 1 340 EL 2 408 2 10 D AND STANDARD POND HALFLIE 11540 T2 VALUES DAYS 49 2 TIel 0 0 ETABOLIC FIELD DAYS UNTIL RAIN RUNOFF HYDROLYSIS P POND HOTOLYSIS POND EFF ETABOLIC POND COMBINE POND D 30 50 ECs 2 IN PPB N A 0 00 0 00 9 00 EC AVERAGE DAY GEE 11 01 DO YOU WANT 8 ANOTHER RUN Y OR N gt 9 00 Questions 1 What is the estimated What is the estimated environmental concentration EEC 2 If the No Observable Effect Concentration NOEC for chlorpyrifos is 5 ug I would ad
4. ZOL 814 Chemodynamics Generic Expected Environmental Concentration Program GENEEC Background The GENEEC model is used to calculate the Expected Environmental Concentration EEC for a generic aquatic pond environment adjacent to an agricultural field The simulation provided an analytical tool to assess the potential for adverse effects of pesticides on adjacent aquatic environments This is not a predictive tool but rather used in a conservative Tier I risk assessment See the users manual for earlier versions on diskette for a more detailed description of the model There is no user manual for the beta version 1 3 most recent version that we will be using in class GENEEC version 1 3 mimics a PRZM EXAMS simulation of a generic 10 ha row crop field draining into a 1 ha farm pond of depth 1 m It also incorporates the Tier 1 spray drift model of the U S Spray Drift Task Force to provide an estimate of spray drift loading The model contains numerous conservative assumptions appropriate for a screening level model One aspect of this generic model that prevents realistic simulation of late season foliar applications is that 1t does not take into account foliage factors such as interception of spray foliar dissipation prior to rainfall or pesticide wash off fraction The predicted generic concentrations should not be interpreted as accurate estimates instead they are merely screening levels upper bound estimates In this exercise we
5. pected to occur in a pond near a cotton field treated with chlorpyrifos The model can be found at the course website http www msu edu course zol 814 Download the model onto your computer To run the model get a dos prompt and type GENEECX at the prompt Below are the input screens that you will see when making inputs parameterizing into the model After you run the model answer the questions VERSION 1 3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U S ENVIRONMENTAL PROTECTION AGENCY R ONE SCREENING MODEL UATIC PESTICIDE EXPOSUR BETA TEST VERSION EASE FAX COMMENTS TO RKER 703 305 6309 EASE CHOOSE THE LETTER OF THE APPLICATION YOU WISH TO USE ROW CROPS ORCHARDS GRASSI AND TURF RICE CRANBERRIES DITCHBANKS AND RIGHTS OF WAY GE ROWCROPS O RDS AND TURF ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U S ENVIRONMENTAL PROTECTION AGENCY R ONE SCREENING MODEL UATIC PESTICIDE EXPOSUR PROGRAM TO CALCULATE A SET OF GENERIC ENVIRONMENTAL CONCENTRATION GEEC VALUES ULTING FROM RUNOFF FROM A TEN HECTARE FIELD INTO E HECTARE BY TWO METER DEEP STATIC WATER BODY
6. verse effects be expected based on this scenario 3 Chlorpyriphos is an organo phosphate insecticide that is acutely toxic by depressing achetylcholinesterase AchE activity in the brain It has a low acute to chronic ration For these reasons which of the EEC values generated by GENEEC would be the most appropriate to which to compare a threshold for effects concentration 4 What assumptions are made in this model 5 How accurate is the model 6 How generalized are the results 7 What are the most important parameters in the model 10 8 How could the model predictions be improved 9 Draw the structure of the model 10 Perform a sensitivity analysis for the Kd value To do this run several simulations with a range of values for Kd How sensitive is the model to values used for Kd 11 12
7. will estimate the environmental concentrations of the organophosphorus insecticide chlorpyrifos used in cotton under Australia conditions Application information for this example was provided by Dr Paul Hughes Dow AgroSciences Australia Chemical properties and environmental fate parameters were taken from the United States Department of Agriculture Agricultural Research Service Pesticide Properties Database This database has been subjected to peer review by registrants but has not been updated recently However it is judged to be a reasonably accurate compilation of data and representative values provided in the database are based on objective unbiased selection procedures Aquatic degradation half lives for all the processes accounted for in GENEEC aerobic degradation hydrolysis and photolysis are not uniformly available for all of the compounds in the database In this example field estimated lumped first order dissipation from the water column was entered arbitrarily as a rate for aerobic degradation USEPA prefers laboratory values for individual processes Below you will find the individual screens that will appear when you execute the model Follow these and input the data into the model When you have completed the simulation your instructors will assist you in interpreting the information and discuss how it is used in a Tier I ecological risk assessment Use GENEEC to simulate the concentration of chlorpyrifos that would be ex
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