UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C

Transcription

1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES December 3, 2003 Subject: To: Trifluralin Drinking Water Assessment for Tolerance Reassessment Eligibility Decision (PC Code: ; DP Barcode: D296624) Richard Griffin, Risk Assessor Reregistration Branch I Health Effects Division (7509C) John Pates, Chemical Review Manager Reregistration Branch II Special Review and Reregistration Division (7508C) From: Approved By: Santhini Ramasamy, Environmental Scientist James Hetrick, Senior Physical Scientist Environmental Risk Branch I Environmental Fate and Effects Division (7507C) Sid Abel, Branch Chief Environmental Risk Branch I Environmental Fate and Effects Division (7507C) This memorandum provides the drinking water concentrations for the trifluralin s Tolerance Reassessment Eligibility Decision (TRED). Trifluralin is a soil incorporated herbicide registered for use on a wide range of food crops as well as for some non-food crop uses such as turf and ornamentals (refer to the use closure memo, dated February 12, 2003 for the details on the uses of trifluralin). The drinking water assessment is based on modeling and monitoring data. Modeling was performed for parent as well as combined triflualin residues [i.e., trifluralin and its major environmental degradation products (>10% of applied)] from fate studies. Major degradation products include (5-trifluoromethyl-3-nitro-1,2-benzene diamine,tr-6), (2-ethyl-7-nitro- 5-trifluoromethyl benzimidazole, TR-15), and the ααα-trifluoro-5-nitro- N4,N4-dipropyl toluene-3,4,diamine,tr-4. Degradation products were considered in the assessment to account for potential identification of degradation products of toxicological concern by the Health Effects Division (HED) Metabolism Assessment Review Committee.

2 Surface Water FIRST Modeling (Tier I) Tier I FIRST modeling was conducted using application rates for sugar cane (4.0 lbs ai/a). This application rate was selected because it is the highest application rate for all trifluralin uses. The daily peak concentration of trifluralin is not likely to exceed 66.9 ppb. The annual average concentration of trifluralin is not likely to exceed 6.6 ppb. For combined trifluralin residues (parent and degradation products), the peak daily and annual average concentrations are not likely to exceed 72.5 and 17.6 ppb, respectively. PRZM/EXAMS Modeling (Tier II ) Since trifluralin is registered on several crops, Tier II modeling crop scenarios were selected to reflect crops with the highest uses of trifluralin (e.g. soybeans, cotton), the maximum application rate (e.g., sugarcane), and availability of scenarios. GIS analysis indicates the selected scenarios generally represent moderate to high trifluralin use area (i.e., $11 lbs ai/mi 2 )(Figure 1).

3 Figure 1. PRZM/EXAMS Scenario Locations

4 Among the crops modeled (soybeans, cotton, canola, tomatoes, wheat, carrots, cabbage, sugarcane, turf and ornamentals), the maximum environmental concentrations were obtained for sugarcane applied as a single aerial application at 4.0 lbs ai/acre. Trifluralin is a volatile pesticide (Henry Constant =1.62E -4 atm m 3 /mole and vapor pressure= 1.10E -4 Torr). It has been detected in both rain and air samples in environmental monitoring programs (Coupe et al. 2003, Rice et al 2003). Modeling of volatilization rates from soil, as modeled by PRZM, were assumed to be captured through the aerobic soil metabolism half-life. In the reservoir, volatilization was simulated using the Henry s Constant and vapor pressure. For the sugarcane use, the 1 in 10 year daily peak concentration of trifluralin is not likely to exceed 38.1 ppb. The 1 in 10 year annual average concentration is not likely to exceed 1.9 ppb. The 30 year annual average concentration is not likely to exceed 1.3 ppb. For combined trifluralin residues, the concentration is not likely to exceed 38.4 ppb for the 1 in 10 year daily peak concentration, 2.0 ppb for the 1 in 10 year annual average concentration, and 1.4 ppb for the 30 year annual average concentration. Concentrations from Tier II model simulation are presented in Table A2. Surface Water Monitoring Data Surface water monitoring data for trifluralin were obtained from the USGS National Water Quality Assessment (NAWQA) data ( and USGS/EPA pilot reservoir monitoring program data (Blomquist, et al. 2001). Surface water monitoring data were analyzed by location (sampling station) and year of sampling. Data analysis included identification of NAWQA sampling stations with trifluralin detections, determination of peak concentration of trifluralin, and calculation of time weighted annual means (TWAM). The minimum criteria for calculating TWAM concentration at a sampling station in a given year was a single detection of trifluralin. Non-detections were assumed to be equivalent to the minimum detection limit (MDL). This data handling approach was taken because of the highly censored data (low detection frequencies) for trifluralin. The equation used for calculating the time weighted annual mean is as follows: [(( T 0+1 -T 0 ) + ((T 0+2 -T 0+1 )/2))*C t 0+1 )] + (((T i+1 -T i-1 )/2)*C i ) + [((T end -T end-1 ) + ((T end-1 -T end-2 )/2)*C Tend-1 )]/365 where: Ci=Concentration of pesticide at sampling time (Ti) Ti= Julian time of sample with concentration Ci T 0 =Julian time at start of year=0 T end =Julian time at end of year=365 4

5 Trifluralin was analyzed in water samples using USGS analytical schedule 2001 ( Zaugg, et al. 1995). The method uses a solid phase extraction on C-18 column coupled with chemical analysis using GC/MS with single ion mode for selective confirmation and quantification of pesticides. Trifluralin has a peak retention time of minutes. Recoveries of trifluralin were determined in surface water (South Platte River near Henderson, CO), ground water (Jefferson County, CO near Denver Federal Center), and reagent-water. Method detection limit (MDL) is defined as the minimum concentration with 99 percent confidence the measured concentration is greater than zero. Seven replicate samples at 0.1 ug/l were used to establish a preliminary MDL. The MDL for trifluralin was ug/l (59% of recovery) in reagent water. The percent recovery of trifluralin at 0.1 to 1 µg/g ranged from 63% to 64% in surface water and 44% to 54% in ground water. NAWQA/USGS The peak surface water concentration of trifluralin from the USGS NAWQA (United States Geological Survey National Water-Quality Assessment) monitoring program is 1.74 ug/l from the San Joaquin Study Unit [Del Puerto at vineyard road near Patterson, California (Sampling Station No )]. The highest time weighted annual mean concentration is ug/l from the San Joaquin Study Unit [Hospital CA River Rd near Patterson, California (Sampling Station No )]. Trifluralin was detected in 15% (2,560 detections/17,637 samples) of surface water samples in the NAWQA database. Trifluralin detections were generally associated with watersheds with agricultural use patterns. The surface water concentration in the NAWQA database were ranked and the percentile values are reported in Table 1. Table 1: The percentile values of surface water and ground water concentrations greater than the MRL from the NAWQA database for trifluralin Percentile for Monitoring Concentrations NAWQA Surface Water Data (µg/l) NAWQA Time Weighted Annual Mean (µg/l) 100% % < 0.05* % <0.009* % <0.009* % <0.002* *- Indicates reported concentration is method detection limit (MDL) 5

6 USGS/EPA Pilot Reservoir Monitoring Data Trifluarlin was detected in the USGS/EPA pilot reservoir monitoring study at the CA, PA, LA, and SD reservoirs (Blomquist, et al. 2001). Detection frequencies of trifluralin were low in both intake (2.8%) and treated (2.2%) water. A maximum of two detections, designated as estimates E, were found in the intake water samples at the PA reservoir in 2000 and the LA reservoir in Estimated concentrations are defined as concentrations below the method detection limit (MDL). Estimated trifluralin concentrations in both intake and finished water samples were comparable to the MDL ( ug/l). Table 2 Maximum Estimated Concentrations and Number of Detections in the USGS/EPA Pilot Reservoir Monitoring Project Reservoir Intake Water Finished Water Location Year Conc. (µg/l) # of Detects Conc. (µg/l) # of Detects CA No Detections PA PA LA LA No Detections SD The TWAM concentration of trifluralin ranged from to ug/l in intake water samples and to ug/l in finished water samples (Table 3). As expected, the TWAM concentration reflect the range of MDLs in the monitoring data. For trifluralin, the typical MDLs is <0.002 ug/l. 6

7 Table 3: Trifluralin detections found in the USGS/EPA Pilot Reservoir Monitoring Project Reservoir TWAM Water Conc. (µg/l) Location Year Intake Finished CA No Detections PA PA LA LA No Detections SD Ground Water Modeling SCI-GROW modeling was performed for sugarcane because it represents the highest application rate (4.0 lbs ai/acre). The estimated shallow ground water concentration for trifluralin and trifluralin residues is not likely to exceed µg/l. Predicted concentrations of trifluralin and combined trifluralin residues in ground water are the same because major degradation products of trifluralin were formed through degradation processes (e.g., photodegradation). Photodegradation is not considered in the SCI-GROW model. Ground Water Monitoring Data Ground water monitoring data for trifluralin were obtained from the USGS National Water Quality Assessment (NAWQA) data ( The peak ground water trifluralin concentration from USGS NAWQA is µg/l. Trifluralin was detected in 0.5% (49 detections/10,083 samples) in ground water samples. The ground water detections were ranked and the percentile values are reported in Table 4. 7

8 Table 4: The percentile values of ground water concentrations reported in NAWQA database for trifluralin Percentile for Monitoring Concentrations NAWQA Ground Water Data (µg/l) 100% % < % < % < % <0.009 GIS Characterization of Trifluralin Surface and Ground Water Monitoring Data A GIS analysis indicates trifluralin use is widespread across the United States (Figure 2) The highest trifluralin use areas (51 to 175 lbs of trifluralin/mile 2 ) are found in the Mississippi Embayment, Red River Basin, Northwestern Iowa, Southwestern Minnesota, and Western Panhandle of Texas. Moderate trifluralin use (11-50 trifluralin/mile 2 )) can be found in most of mid-western corn belt, Great Plains, and the Central Valley of California, Coastal Plains of North Carolina and Georgia, and the Mississippi Embayment. NAWQA surface and ground water sampling stations are located in the moderate to high trifluralin use regions (Figure 3 and 4). In these regions, the maximum trifluralin concentrations were greater than <0.02 ug/l (Figure 5). There are few community water systems (CWS) surface water intake locations associated within areas of moderate to high trifluralin use (Figure 6). The GIS analysis indicates the NAWQA sampling locations appear to reflect trifluralin use areas. 8

9 Figure 2. Trifluralin Use Areas

10 Figure 3. NAWQA Surface Water Locations and Trifluralin Use Area

11 Figure 4. NAWQA Groundwater Locations and Trifluralin Use Area

12 Figure 5. NAWQA Surface Water Detections Greater Than 0.02 ppb and Trifluralin Use Area 12

13 Figure 6. Community Water System Intake Locations and Trifluralin Use Area 13

14 Comparison of Predicted Trifluralin Concentrations and Monitoring Data The maximum daily peak concentration of trifluralin from PRZM/EXAMS simulation (38.1 ppb) is greater than the highest concentration in the USGS/NAWQA monitoring database (1.74 ppb). However, the maximum annual average trifluralin concentration in surface water (1.9 ppb) is comparable to TWAM concentrations in USGS monitoring studies (0.618 ppb). Additionally, the maximum trifluralin concentration in shallow ground water (0.035 ppb), as predicted through SCI-GROW, is lower than concentrations in the NAWQA ground water monitoring database (0.150 ppb). Uncertainties, Limitations, and Assumptions There are no aerobic aquatic degradation data for trifluralin. A default aerobic aquatic degradation half-life was calculated as twice the aerobic soil metabolism half-life. Submission of aerobic aquatic metabolism data is expected reduce uncertainties in the aquatic metabolism of trifluralin. Volatilization of trifluralin was not directly modeled in the PRZM scenario. Because the aerobic soil metabolism half-life represents both degradation and volatilization, the aerobic soil metabolism half-life was used to jointly describe degradation and volatilization processes. Cumulative trifluralin residue modeling accounted for only major degradation products (>10% of the applied radioactivity) identified in fate studies. The major degradation products were identified only in aqueous photolysis and in anaerobic soil metabolism. There were several degradation products identified in aerobic soil metabolism, but none of these are classified as major degradation products. The uncertainty in the predicted EECs arises from not including the minor degradation products (<10% of applied radioactivity) in the drinking water exposure assessment. There may be uncertainty in the predicted EECs due to the application timing used for modeling. The label, CORNBELT, allows for spring and fall applications. Model simulations are based a fixed application date of March 1 st. EECs are expected to vary according to the date of application. Modeling was conducted using the maximum application rate for specific crops. The use of typical application rates on specific crops is expected to lower predicted concentrations. 14

15 Tier II EECs were adjusted for percent cropped area (PCA) in the watershed. For all the crops modeled except soybeans, cotton and wheat, a default percent cropped area factor of 0.87 was used. The crop specific PCA factors were available for soybeans (0.46), cotton (0.2) and wheat (0.56). If specific PCA factors for other crops, such as canola, tomatoes, carrots, cabbage, sugarcane, turf, and ornamentals were available, it is likely to lower the predicted EECs. Trifluralin degradation products are not analytes on the USGS analytical methods. Therefore, no monitoring data for trifluralin degradation products are available to allow for a comparison of predicted concentrations and actual concentrations of combined trifluralin residues. Although the NAWQA monitoring stations appear to be located (based on county level data) in most of the high trifluralin use areas, the study design of NAWQA was not targeted to account for all trifluralin use areas, timing of application and other factors which may more accurately represent spatially and temporally dependent variables influencing runoff vulnerability. Office of Water Health Advisory Values Based on the 2002 drinking water standards and health advisories (HA), no MCL/MCLG is available for trifluralin. The one day and 10 day health advisories for 10 kg-child are 80 ppb. The Lifetime HA is reported as 5 ppb. Lifetime HA is the concentration of a chemical in drinking water that is not expected to cause any adverse non-carconigenic effects for a lifetime exposure. The lifetime HA is based on exposure of a 70Kg adult consuming 2 Liters of water per day. Drinking Water Equivalent Level (DWEL) is reported as 300 ppb. DWEL is a lifetime exposure concentration protective of adverse, non-cancer health effects, that assumes all of the exposure to a contaminant is from drinking water. The Cancer Risk Health Advisory is reported as 500 ppb at 10-4 cancer risk. 15

16 References Blomquist, J.D., J. M. Denis, J.P. Cowles, J.A. Hetrick, R.D. Jones, and N.R. Birchfield Pesticides in Selected Water-Supply Reservoirs and Finished Drinking Water, : Summary of Results from a Pilot Monitoring Program. USGS Open-File Report Coupe, R. H., M.A. Manning, W.T. Foreman, D.A. Goolsby, and M.S Majewski. December 2, 2003 (downloaded date). Occurrence of Pesticides in Rain and Air in Urban and Agricultural Areas of Mississippi, April-September. USGS. C/2410_Coupe/pdf/2410_Coupe.pdf. Rice, C., C.B. Nochetto, and P. Zara. December 2, 2003 (downloaded date). Volatilization of Trifluralin, Atrazine, Metolachlor, Chloropyrifos, alfa-endosulfan and beta-endosulfan from Freshly Tilled Soil. USDA/ARS. data/ /74/ htlm. Zaugg, S. D., M. W. Sandstrom, S. G. Smith, and Kevin M. Fehlberg Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory Determination of Pesticides in Water by C-18 Solid-Phase Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry with Selected-Ion Monitoring. USGS Open-File Report

17 Appendices FIRST modeling (Tier I) FIRST input parameters are presented in Table A1. Tier I modeling was simulated using sugarcane [CORNBELT label (EPA Reg. No )] because it is the highest seasonal application rate for all trifluralin uses. Two different aqueous photolysis half-lives are presented in the input parameter table, the shorter half-life indicating the degradation for parent and the second longer half-life represents the degradation for the parent along with two major degradates TR-6 and TR-15. No major metabolites are reported for aerobic soil metabolism. Table A1. FIRST Input Parameters for Trifluralin Parameters Input Value and Unit Source of Info/Reference Maximum Application Rate 2.0 lb. ai/acre - sugarcane Product label (EPA Reg. No ) Maximum Number of Applications 2 Product label (EPA Reg. No ) Minimum Interval between Applications (days) 180 Product label (EPA Reg. No ) PCA Factor reservoir.pdf 3 Partition Coefficient Kd 52.5 L/kg (lowest non-sand Kd) type of soil-sandy loam soil MRID Aerobic Soil Metabolism half-life MRID (GLN 162-1) Wetted in No Product label (EPA Reg. No ) Depth of incorporation (inches) 2 Product label (EPA Reg. No ) Method of application Aerial Product label (EPA Reg. No ) Solubility in water 0.3 mg/l at 25 o C RED Aerobic Aquatic Metabolism (t 1/2 ) 438 days (2x aerobic soil metabolism when no data available) Input Parameter Guidance Manual (February 28, 2002) Aquatic Photolysis t 1/2 (days) days (parent) MRID days (combined residues) 2 1 the 90 % upper confidence bound on the mean metabolism half -life obtained from three half-life values (189, 201, 116 days) was used 2 Represents parents and degradates. The degradates include TR-4 (α,α,α,-trifluoro-5-nitro-n4,n4-dipropyl toluene- 3,4,diamine), TR-6 (5-trifluoromethyl-3-nitro-1,2-benzene diamine) and TR-15 (2-ethyl-7-nitro-5- trifluoromethylbenzimidazole) 3 OPP Pesticide Science Policy, Part B: Applying a Percent Crop Area Adjustment to Tier 2 Surface Water Model Estimates for Pesticide Drinking Water Exposure Assessment. 17

18 The FIRST generated model output files for parent and combined residues are presented below. Parent Alone RUN No. 1 FOR Trifluralin ON Sugarcane * INPUT VALUES * RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Kd (PPB ) (%DRIFT) AREA (IN) ( 3.131) AERIAL(16.0) FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.) N/A UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.0 AUG 1, PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION Combined Residues RUN No. 2 FOR Trifluralin ON Sugarcane * INPUT VALUES * RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Kd (PPB ) (%DRIFT) AREA (IN) ( 3.131) AERIAL(16.0) FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.) N/A UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.0 AUG 1, PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

19 PRZM/EXAMS Modeling Table A2 presents the surface water concentrations for parent and the combined residues (parent and three degradates) for various crop scenarios by Tier II modeling. Table A2. Tier II Drinking Water Concentrations Using PRZM/EXAMS Modeling for Trifluralin Uses Crop Scenarios 1 in 10 year Peak Concentration (ppb) 1 in 10 year Annual Daily Average Concentration (ppb) 30-year Annual Daily Average Concentration (ppb) Trifluralin Trifluralin + Degradates 1 Trifluralin Trifluralin+ Degradates 1 Trifluralin Trifluralin+ Degradates 1 SoybeansMS 2.0lbs a.i./a, 1x CottonMS 2.0lbs a.i./a, 1x CanolaND 1.0 lb a.i./a, 1x TomatoesFL 1.0 lb a.i./a, 1x WheatND 1.0 lb a.i./a, 1x CarrotsFL 1.0 lb a.i./a, 1x CabbageFL 1.0 lb a.i./a, 1x SugarcaneLA 4.0 lb a.i./a, 1x SugarcaneLA 2.0 lb a.i./a, 2x, 180 days intervals TurfFL 1.0 lb a.i./a, 2x 56 days intervals TurfPA 1.0 lb a.i./a, 2x 56 days intervals OrnamentalsOR 4.0 lb a.i./a, 1x OrnamentalsOR 2.0 lb a.i./a, 2x 56 days intervals Degradates include TR-4 (α,α,α,-trifluoro-5-nitro-n4,n4-dipropyl toluene-3,4,diamine), TR-6 (5-trifluoromethyl-3-nitro-1,2- benzene diamine) and TR-15 (2-ethyl-7-nitro-5-trifluoromethylbenzimidazole) 19

20 The input parameters used for the Tier II modeling are presented in Table A3. The modeling was performed with index reservoir scenarios and the concentrations are adjusted to percent cropped area factors (PCA). A default PCA factor of 0.87 was used for all the crops except for soybeans, cotton and wheat. The crop specific PCA factors used for soybeans, cotton and wheat are presented in Table A4. Table A4 also presents the information on the crop scenarios selected and specific information on application period, method of application, application efficiency and spray drift factor used for modeling. The CORNBELT label specifies a wide range of application periods, i.e., Spring applications (any time after January 1) and Fall applications (September 1 and December 31). A single application date (March 01) was selected for all crop scenarios for the simplicity of modeling. The input parameters used for PRZM/EXAMS modeling are presented in Table A3 and Table A4. Table A3. PRZM/EXAMS Input Parameters for Trifluralin Parameters Input Value and Unit Source of Info/Reference Maximum Application Rates 2.0 lbs a.i/a (Soybeans, Cotton) Cornbelt Label (EPA Reg No ) Soil Partition Coefficient, Kd 1.0 lb a.i./a (Canola, Tomatoes, Wheat, Carrots, Cabbage) 2.0 lb a.i./a 2x, 180 days intervals or single application of 4.0 lb/a (Sugarcane) 1.0 lb a.i./a, 2x 56 days interval (cool season) (Turf) 2.0 lb a.i./a 2x 56 days interval assumed similar to Turf (Ornamentals) 52.5 L/Kg (Lowest nonsand Kd) sandy loam Cornbelt Label (EPA Reg No ) Cornbelt Label (EPA Reg No ) Based on EPA Use closure memo and SMART Meeting Based on EPA Use closure memo and SMART Meeting MRID Molecular Weight Solubility in Water 0.3 ppm at 25 o C Vapor Pressure 1.10E-4 Torr (RED) Henry s Law Constant 1.62E-4 atm m3/mole (RED) Hydrolysis T 1/2 Stable at ph 5, ph 7, ph 9 MRID Aqueous Photolysis (ph 5) T 1/2 Aerobic Soil Metabolism T 1/ days (Parent) 9.43 days (Parent and degradates, TR-6,TR-15) 219 days (90% upper confidence bound on the mean metabolism half-lives, 189, 201, 116 days) MRID MRID:

21 Table A3. PRZM/EXAMS Input Parameters for Trifluralin Anaerobic Soil Metabolism T 1/2 Aerobic aquatic metabolism T 1/2 59 days (Parent) (90% upper confidence bound on the mean metabolism half-lives, 59, 25, 35 days) 68 days (Parent and degradate, TR-4) (90% upper confidence bound on the mean metabolism half-lives, 63, 31, 55 days) 438 days (2x aerobic soil metabolism input value when no data available) MRID Guidance Manual (Feb 28, 2002) Table A4. Other Input parameters for PRZM/EXAMS Modeling PCA factor Used for Drinking Water Assessment Crops/Crops Scenarios Method of Application Application Efficiency Spray Drift Application Date and Month Crop Scenario Modeled PCA Factor Used Soybeans Aerial March 01 MS 0.41 Cotton Aerial March 01 MS 0.2 Canola Aerial March 01 ND 0.87 Tomatoes Aerial March 01 FL 0.87 Wheat Aerial March 01 ND 0.56 Carrots Aerial March 01 FL 0.87 Cabbage Aerial March 01 FL 0.87 Sugarcane Aerial March 01 LA 0.87 Turf Ground March 01 FL and PA 0.87 Ornamentals Ground March 01 OR 0.87 The input and output files generated from Tier II modeling for the various crop scenarios are presented in the subsequent pages. 21

22 PRZM input and output files Parent - Soybeans stored as IrTrSyMS.out Chemical: Trifluralin PRZM environment: MSsoybeanC.txt "modified Satday, 12 October 2002 at 17:07:44" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w13893.dvf "modified Wedday, 3 July 2002 at 09:06:20" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

23 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrSyMS Metfile: w13893.dvf PRZM scenario: MSsoybeanC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual 23

24 Incorporation Depth: DEPI 5 cm Application Rate:TAPP 2.24 kg/ha Application Efficiency: APPEFF0.95 fraction Spray Drift DRFT 0.16 fraction of application rate applied to pond Application Date Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm Record 17: FILTRA IPSCND1 UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR IR Flag for runoff calc. RUNOFF total "none, monthly or total(average of entire run)" 24

25 Parent - Cotton stored as IrTrCoMS.out Chemical: Trifluralin PRZM environment: MScottonC.txt "modified Wedday, 22 January 2003 at 11:52:38" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w03940.dvf "modified Wedday, 3 July 2002 at 09:05:46" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

26 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrCoMS Metfile: w03940.dvf PRZM scenario: MScottonC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual Incorporation Depth: DEPI 5 cm Application Rate:TAPP 2.24 kg/ha Application Efficiency: APPEFF0.95 fraction 26

27 Spray Drift DRFT 0.16 fraction of application rate applied to pond Application Date Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm Record 17: FILTRA IPSCND1 UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR IR Flag for runoff calc. RUNOFF total "none, monthly or total(average of entire run)" 27

28 Parent - Canola stored as IrTrCaND.out Chemical: Trifluralin PRZM environment: NDcanolaC.txt "modified Tueday, 24 September 2002 at 08:20:06" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w24013.dvf "modified Wedday, 3 July 2002 at 09:05:54" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

29 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrCaND Metfile: w24013.dvf PRZM scenario: NDcanolaC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual Incorporation Depth: DEPI 5 cm Application Rate:TAPP 1.12 kg/ha Application Efficiency: APPEFF0.95 fraction Spray Drift DRFT 0.16 fraction of application rate applied to pond Application Date Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm Record 17: FILTRA IPSCND1 29

30 UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR IR Flag for runoff calc. RUNOFF total "none, monthly or total(average of entire run)" 30

31 Parent - Tomatoes stored as IrTrToFL.out Chemical: Trifluralin PRZM environment: FLtomatoC.txt "modified Satday, 12 October 2002 at 16:44:04" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w12844.dvf "modified Wedday, 3 July 2002 at 09:04:30" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

32 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrToFL Metfile: w12844.dvf PRZM scenario: FLtomatoC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual Incorporation Depth: DEPI 5 cm Application Rate:TAPP 1.12 kg/ha Application Efficiency: APPEFF0.95 fraction 32

33 Spray Drift DRFT 0.16 fraction of application rate applied to pond Application Date Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm Record 17: FILTRA IPSCND1 UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR IR Flag for runoff calc. RUNOFF total "none, monthly or total(average of entire run)" 33

34 Parent - Wheat stored as IrTrWhND.out Chemical: Trifluralin PRZM environment: NDwheatC.txt "modified Satday, 12 October 2002 at 17:15:08" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w14914.dvf "modified Wedday, 3 July 2002 at 09:05:52" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

35 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrWhND Metfile: w14914.dvf PRZM scenario: NDwheatC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual Incorporation Depth: DEPI 5 cm Application Rate:TAPP 1.12 kg/ha Application Efficiency: APPEFF0.95 fraction 35

36 Spray Drift DRFT 0.16 fraction of application rate applied to pond Application Date Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm Record 17: FILTRA IPSCND1 UPTKF Record 18: PLVKRT PLDKRT FEXTRC 0.5 Flag for Index Res. Run IR IR Flag for runoff calc. RUNOFF total "none, monthly or total(average of entire run)" 36

37 Parent - Carrot stored as IrTrCrFL.out Chemical: Trifluralin PRZM environment: FLcarrotC.txt "modified Tueday, 28 January 2003 at 15:47:50" EXAMS environment: ir298.exv "modified Thuday, 29 August 2002 at 15:34:12" Metfile: w12844.dvf "modified Wedday, 3 July 2002 at 09:04:30" Water segment concentrations (ppb) Year Peak 96 hr 21 Day 60 Day 90 Day Yearly Sorted results Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

38 Average of yearly averages: Inputs generated by pe4.pl - 8-August-2003 Data used for this run: Output File: IrTrCrFL Metfile: w12844.dvf PRZM scenario: FLcarrotC.txt EXAMS environment file:ir298.exv Chemical Name: Trifluralin Description Variable Name Value Units Comments Molecular weightmwt g/mol Henry's Law Const. henry 1.62E-04 atm-m^3/mol Vapor Pressure vapr 1.10E-04 torr Solubility sol 3 mg/l Kd Kd 52.5 mg/l Koc Koc mg/l Photolysis half-life kdp 0.37 days Half-life Aerobic Aquatic Metabolism kbacw 438 days Halfife Anaerobic Aquatic Metabolism kbacs 59 days Halfife Aerobic Soil Metabolism asm 219 days Halfife Hydrolysis: ph 7 0 days Half-life Method: CAM 4 integer See PRZM manual Incorporation Depth: DEPI 5 cm Application Rate:TAPP 1.12 kg/ha Application Efficiency: APPEFF0.95 fraction 38