OFFICE OF

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

PC Code: 036101

Decision #: 463234

DP Barcode: 401006

Date: July 02, 2012

 

MEMORANDUM

SUBJECT: Drinking Water Exposure Assessment to Establish Tolerances of Parent 

Trifluralin and its Degradates for Oilseed Crop Group 20.

TO: Andrew Ertman, Risk Manager Reviewer

Barbara Madden, Risk Manager

Registration Division (7505C)

FROM: Faruque Khan, Ph.D., Senior Fate Scientist

Nancy Andrews, Ph.D., Branch Chief 

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

A screening-level drinking water assessments was conducted for the petition submitted 

by the IR-4 Project to expand canola/rapeseed, sunflower seed and cottonseed tolerances of 

trifluralin herbicide to include oilseed crop group 20. This is an abbreviated drinking water 

assessment to provide estimated drinking water concentrations (EDWCs) of trifluralin and its 

major degradates (TR-4, TR-6 and TR-15) in surface water and ground water in support of 

human health risk assessment. The assessment is based on drinking water assessment previously 

performed for the Tolerance Reassessment Eligibility Decision (TRED) (D296624, December 3, 

2003). The EDWCs for oilseed crops are based on the maximum proposed application rates for 

aerial and ground applications specified in the proposed product labels (Treflan®HFP, and 

Treflan®TR-10). 

Modeling was performed using a total toxic residue method combining trifluralin 

degradates of concern [i.e. trifluralin and its major environmental degradation products (≥10% of 

applied)] from fate studies. Major degradation products are TR-4 ( α,α,α -trifluoro-5-nitroN4,N4-dipropyl-toluene-3,4-diamine), TR-6 (5-trifluoromethyl-3-nitro-1,2-benzenediamine) and 

TR-15 (2-ethyl-7-nitro-5-(trifluoromethyl) benzimidazole). The EDWCs of total toxic trifluralin 

residue for various crops were generated with the coupled models PRZM and EXAMS for 

surface water and SCI-GROW for ground water. Current versions of surface water and ground 

water models as well as the guidance of model input were updated multiple times since the

previous drinking water assessment was performed for the 2003 TRED (US EPA, 2003). 

Detailed updates of various models and the guidance for model inputs can be obtained from
2

URL: http://www.epa.gov/oppefed1/models/water/ . Therefore, in addition to the proposed 

expansion of tolerances to oilseed crop group 20, this assessment also re-evaluates the existing 

sugarcane use to reflect the highest EDWCs in the previous drinking water assessment (US EPA, 

2003). 

The upper-bound EDWCs for trifluralin and its major degradates are provided in Table 1

for the human health risk assessment. The most conservative estimates were obtained from aerial 

application of trifluralin for LA Sugarcane as a surrogate scenario for Hawaii at the maximum 

labeled annual application rate of 4 lbs a.i./acre, applied twice annually at 2 lbs a.i./acre. The

updated EDWCs for sugarcane are lower than the previously reported EDWCs in the TRED 

(U.S. EPA 2003) due to two applications at 2.0 lbs a.i./A as prescribed in current labels instead 

of 1 application at 4.0 lbs/A per year used in the previous assessment. Based on the results of 

current modeling, EFED recommends an acute EDWC of 23.83μg/L, a chronic EDWC of 

1.97μg/L and a cancer chronic EDWC of 1.35μg/L for surface water be used in the human

health risk assessment. 

SCIGROW modeling was performed for oilseeds as well as sugarcane because it 

represents the highest application rate (4.0 lbs/A). The estimated shallow groundwater 

concentration for trifluralin is not likely to exceed 2.75E-02 μg/L (Table 1). Since there is no 

major degradate formed in soil, the predicted concentration represent total toxic residue of 

trifluralin. The predicted value also represents both acute and chronic exposures. However,

SCIGROW predicted maximum trifluralin concentration for ground water is lower than the 

concentration of 0.15 μg/L reported in NAQWA Ground Water Monitoring Database (USGS 

2012). EFED recommends using NAQWA groundwater monitoring value of 0.15 μg/L for acute, 

chronic and cancer chronic exposures in groundwater for human health risk assessment.

In conclusion, EDWCs generated by the scenarios are expected to be generally 

representative of concentrations that would result from field application of trifluralin on the 

simulated scenarios. EFED suggests using above recommendations for surface and groundwater 

exposures values for human health risk assessment. 

Table 1. Estimated Drinking Water Concentrations (EDWCs) of trifluralin and its 

degradates for surface water using PRZM/EXAMS and groundwater using SCIGROW 

Drinking Water 

Source (model)

Use

Scenario

(modeled rate)

1-in-10 year acute

(μg/L)

1-in-10 year chronic

(μg/L)

30- year average 

(μg/L)

Surface Water 

(PRZM/EXAMS)

Sugarcane:

FL Sugarcane STD

(2 app. X 1.0 lbs ai/acre)

3.89 (A)1 0.74(A) 0.59(A)

Sugarcane:

LA Sugarcane STD (2 app. 

X 1.0 lbs ai/acre)

LA Sugercane STD 2 app. 

X 2.0 lbs ai/acre)

2

11.92(A)

23.83 (A)3

19.37 (G) 4

0.99(A)

1.97(A) 3

1.76 (G) 4

0.80(A)

1.59(A) 3

1.35 (G) 4
3

Table 1. Estimated Drinking Water Concentrations (EDWCs) of trifluralin and its 

degradates for surface water using PRZM/EXAMS and groundwater using SCIGROW 

Drinking Water 

Source (model)

Use

Scenario

(modeled rate)

1-in-10 year acute

(μg/L)

1-in-10 year chronic

(μg/L)

30- year average 

(μg/L)

Oilseed:

CA Cotton STD 

1app. X 2.0 lbs ai/acre)

3

12.82 (A) 0.35 (A) 0.33 (A)

Oilseed:

MS Cotton STD 

1 app. X 2.0 lbs ai/acre)

3

21.35 (A) 1.08 (A) 0.84 (A)

Oilseed:

NC Cotton STD

1 app. X 2.0 lbs ai/acre)

3

19.63 (A) 0.99 (A) 0.88 (A)

Oilseed:

ND Canola STD

1app. X 1.25 lbs ai/acre)

3 8.16 (A) 0.30 (A) 0.25 (A)

Groundwater 

(SCI-GROW)

For sugarcane

(2 app. X 2.0lbs a.i./acre)

Cottonseed

1 app. X 2.0 lbs/Acre

Oil Seed

1 app. X 1.25 lbs a.i./acre

2.75E-025

1.37E-02

8.58 E-03

2.75-025

1.37E-02

8.58 E-03

2.75E-025

1.37E-02

8.58 E-03 1 = Aerial application 2 = LA Sugarcane STD scenario was used as a surrogate scenario to calculate EDWCs for trifluralin uses in Hawaii 3 = Bolded EDWCs are recommended exposure values for surface water sources for human health risk assessment 4 = Ground application. Exposure from ground application of trifluralin is compared with aerial application for the 

highest exposure scenario (LA Sugarcane STD) for sugarcane at 4.0.lbs/a.i./A. 5

= Groundwater EDWC can be used for acute, chronic and cancer chronic concerns

Drinking Water Exposure Modeling

Estimated drinking water concentrations (EDWCs) were generated using EFED’s 

standard suite of models. Based on the proposed trifluralin labels, the oilseed uses being 

addressed are summarized in Table 2. Trifluralin can be applied as foliar spray as well as 

granular spray via ground and aerial applications. 

Table 2. Trifluralin proposed use pattern for oilseed

Crop

Maximum 

Individual

Application Rate

lbs a.i./A

Number of

Applications

Minimum

Application 

Interval 

(days)

Maximum 

Application Rate per 

Season

per Label in

lbs a.i./A

Application 

Method

Cottonseed

Other Oilseed

2.0

1.0 to 1.25

1

1

Not 

applicable 2.0 

1.0-1.25 

Foliar and 

granular via 

Ground/Aerial
4

Models

A. Surface Water Exposure - PRZM/EXAMS

Pesticide Root Zone Model (PRZM v3.12.2, May 12, 2005) and Exposure Analysis

Modeling System (EXAMS v2.98.04.06, April 25, 2005) are simulation models coupled with the 

input PE5.pl shell (PE5, PE Version 5.0, November 15, 2006) to generate EDWCs of trifluralin

residues that may occur in surface water used as drinking water. The PRZM model simulates 

pesticide movement and transformation on and across the agricultural field resulting from crop 

applications. The EXAMS model simulates pesticide loading via runoff, erosion, and spray drift 

assuming a standard watershed of 172.8 ha that drains into an adjacent standard drinking water 

index reservoir of 5.26 ha, an average depth of 2.74 m. A more detailed description of the index 

reservoir watershed can be found in Jones et al., 1998. The coupled PRZM/EXAMS model and 

users manuals may be downloaded from the U.S. Environmental Protection Agency (EPA) 

Water Models web-page (U.S. EPA, 2010). Percent Crop Areas (PCA) that account for the 

maximum area within a watershed that may be planted with the modeled crop are applied to 

concentrations predicted by PRZM/EXAMS.

Several standard scenarios for oilseed crop group 20 were modeled for aerial application. 

Exposure from ground application of trifluralin was also modeled and compared with aerial 

application for the highest exposure scenario (LA Sugarcane STD) for sugarcane with 4.0 lbs

a.i./A. The EDWCs for ground application are lower than the aerial application. In addition to 

the proposed expansion of tolerance to oilseed crop group, this assessment also re-evaluates

existing sugarcane use to reflect the highest EDWCs in the previous drinking water assessment 

(US EPA, 2003). Application dates were assumed to be the first week of crop emergence based 

on crop scenario and label instructions. Since trifluralin can be used on various agricultural and 

non-agricultural settings (U.S. EPA, 1996), the default PCA of 1.0 was used based on 

agricultural and non-agricultural uses of trifluralin according to PCA guidance (U.S. EPA, 2012). 

Inputs for PRZM/EXAMS are listed in Table 3. Table 1 also provides EDWCs for various 

crops. PRZM/EXAMS input parameters and outputs for an example scenario (LA Sugarcane, 

Aerial application) are provided in Appendix A. 

Table 3. PRZM/EXAMS Input Parameters for Trifluralin Proposed Uses 

Parameter Input Value and Unit Comment Source

Scenario FL Sugarcane STD

LA Sugarcane STD

ND Canola STD

CA Cotton Wirrg STD

MS Cotton STD

NC Cotton STD

All available scenarios for each 

use

N/A1

Maximum Single 

Application Rate

lbs a.i./A 

Sugarcane:

1.0 (Continental US)

2.0 (Hawaii)

Oilseed

2.0 (cottonseed)

1.25 (other oilseed)

Label directions

Maximum application rate for 

safflower

Proposed labels

Treflan®HFP & 

Treflan®TR-10
5

Table 3. PRZM/EXAMS Input Parameters for Trifluralin Proposed Uses 

Parameter Input Value and Unit Comment Source

Applications per Year Sugarcane: 2

Oilseed: 1

Label directions. Label 

specifies rates per season 

Proposed labels

Treflan®HFP & 

Treflan®TR-10

Initial Application Date

FL Sugarcane

LA Sugarcane

CA, MS and NC Cottonseed 

ND Canola

March 1

March 1

May 1

May 1

Application Interval (days) Sugarcane: 180

Oilseed: Not applicable

Intervals were selected to 

reflect labeled application 

patterns.

Proposed labels

Treflan®HFP & 

Treflan®TR-10

Application Method Aerial and Ground Label directions Proposed labels

CAM 4 Soil Incorporation: 2 inches Proposed labels &

Input Guidance 3

Hydrolysis (t 1/2) 0 stable MRID 00131100

Spray drift and application 

efficiency

Aerial: 0.16

Ground: 0.064

Efficiency – aerial: 0.95,

Ground 0.99

Input Guidance 2

Aerobic soil metabolism (t1/2) 219 days No major degradate formed 

in aerobic soil metabolism 

study. Upper 90th %-ile 

confidence bound on the 

mean of three half-lives

Input Guidance 2

Aerobic aquatic metabolism 

(t1/2)

438 days 2x aerobic soil metabolism Input Guidance 3

Anaerobic aquatic metabolism 

(t1/2)

68 In absence of anaerobic

aquatic metabolism data, 

soil anaerobic metabolism 

data were used. Half-life 

value based on parent plus 

degradate, TR-4. Upper 90th

%-ile confidence bound on 

the mean of three half-lives

MRID 41240502

Aquatic photolysis (t1/2) 9.43 days Half-life value based on 

parent and degradates, TR-6 

and TR-15

MRID 40560101

Vapor pressure 4.58 ×10-5 Torr (mmHg) 6.1 x 10-3 Pa U.S. EPA, 2004C

Solubility in water 

(pH 7, 20 °C)

0.4 mg/L3 < 1.0 mg/L. A nondefinitive solubility value U.S. EPA, 2004C

Henry’s Law constant (20 °C) 1.03×10-4 atm.m3 /mol --- Toxnet4

Molecular weight 335.28 --- U.S. EPA, 2004C

Partition coefficient Koc 8757.9 mL/g Average Koc (6413, 6748, 

8457 and 13413) 

MRID 40673501

1 = Not applicable

2 = 3 = US EPA 2010b http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm 3 = U.S. National Research Council, 1977

4 = http://toxnet.nlm.nih.gov/
6

B. Ground Water Exposure-SCIGROW

Screening Concentration in Ground Water (SCI-GROW v2.3, Jul. 29, 2003) is a

regression model used as a screening tool to estimate pesticide concentrations found in ground 

water used as drinking water. SCI-GROW was developed by fitting a linear model to ground 

water concentrations with the Relative Index of Leaching Potential (RILP) as the independent 

variable. Ground water concentrations were taken from 90-day average high concentrations 

from Prospective Ground Water studies. The RILP is a function of aerobic soil metabolism and 

the soil-water partition coefficient. The output of SCI-GROW represents the concentrations of

residues that might be expected in shallow unconfined aquifers under sandy soils, which is 

representative of the ground water most vulnerable to pesticide contamination and likely to serve 

as a drinking water source. The SCI-GROW user’s manual and information concerning the 

model can be found on the EPA Water Models web-page (USEPA, 2010c). SCIGROW input 

parameters are provided in Table 4 and output in Appendix A. 

Table 4. SCI-GROW Input Parameters for Trifluralin New Uses 

Variable Description Input Value

Soil half-life (day) Use the mean value of 169 days for acceptable aerobic 

soil half-lives (189, 201, and days)

Pesticide partition or distribution 

coefficients, Koc

8757.9 mL/g (mean value)

Application rate 

Sugarcane (Hawaii)

Sugarcane (Continental U.S) 

Cottonseed

Oilseed crops

2 applications @2.0 lbs a.i./A 

2 applications @1.0 lbs a.i./A 

1 application @2.0. lbs a.i./A

1 application @1.25. lbs a.i./A 

Monitoring Data

The trifluralin TRED provided a comprehensive summary of a number of monitoring 

studies. Surface water monitoring data for trifluralin were obtained from the USGS’s National 

Water Quality Assessment (NAWQA) program and USGS/EPA pilot reservoir monitoring 

program data (Blomquist et al., 2001). Trifluralin detections were generally associated with 

watersheds with agricultural use patterns. Trifluralin was detected in 15% of surface water 

samples in the NAQWA database. The highest surface water concentration from USGSNAQWA monitoring program is 1.74 μg/L from the San Joaquin study unit of California. 

Trifluralin was also 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. Estimated trifluralin concentrations in both intake 

and finished water samples were comparable to the method of detection (MDL) of 0.002 μg/L.

Ground water monitoring data for trifluralin were obtained from USGS-NAQWA data. 

Trifluralin was detected in 0.5% of ground water samples. The highest groundwater trifluralin 

concentration, 0.15 μg/L, was detected in Sumter, GA. 
7

Uncertainties, Limitation and Assumption

• There is no aerobic aquatic degradation data from trifluralin. A default aerobic aquatic 

degradation half-life was estimated as twice the aerobic soil metabolism half-life. 

Submission of aerobic aquatic metabolism data is expected to 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 soil 

metabolism half-life was used to jointly describe degradation and volatilization 

processes.

• Total toxic residue of trifluralin modeling accounted for only major degradation products 

(>10% of the applied) identified in fate studies. The major degradation products were 

identified only in aqueous photolysis and in anaerobic soil metabolism studies. There 

were several degradation products identified in aerobic soil metabolism, but none of these 

are classified as major or toxic degradation products. The uncertainty in the predicted 

EDWCs arises from not including the minor degradation products in the drinking water 

exposure assessment. 

REFERENCES

Blomquist, J.D., J.M. Denis, J.P. Cowles, J.A. Hetrick, R.D. Jones, and N.R. Birchfield. 2001. 

Pesticide in Selected Water Supply Reservoirs and Finished Drinking Water, 1999-2001. 

Summary of Results from Pilot Monitoring Program. USGS open-File report 01-456.

Jones, R. D., S. Abel, W. R. Effland, R. Matzner, R. Parker. 1998. An Index Reservoir for Use 

in Assessing Drinking Water Exposure. Proposed Methods for Basin-scale Estimation of 

Pesticide Concentrations in Flowing Water and Reservoirs for Tolerance Reassessment. 

Presentation to FIFRA Science Advisory Panel, June 29-30, 1998. Online at: 

http://www.epa.gov/scipoly/sap/1998/index.htm

U.S. EPA. 2012. Development and Use of Percent Cropped Area and Percent Turf Area 

Adjustment Factors in Drinking Water Exposure Assessments: 2012 Update . U.S. 

Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Office 

of Pesticide Programs, Environmental Fate and Effects Division. 

http://www.epa.gov/oppefed1/models/water/pca_adjustment_dwa.html

U.S. EPA. 2010b. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides, Version 2.1. U.S. Environmental Protection Agency, Office of 

Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate 

and Effects Division, October 22, 2009. 

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm
8

US EPA. 2010c. Water Models. U.S. Environmental Protection Agency, Pesticides: Science 

and Policy. Online at: http://www.epa.gov/oppefed1/models/water/

U.S. EPA. 2005. PRZM-3, A Model for Predicting Pesticide and Nitrogen Fate in the Crop 

Root and Unsaturated Soil Zones: Users Manual for Release 3.0. May 2005.

U.S. EPA. 2003. Trifluralin-Drinking water assessment for tolerance reassessment eligibility 

decision. (DP 296624). U.S. Environmental Protection Agency, Office of Prevention, Pesticides 

and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division, 

December 3, 2003.

U.S. EPA. 1996. Reregistration Eligibility Decision (RED) Trifluralin. United States Office of 

Prevention, Pesticides EPA Environmental Protection And Toxic Substances April 1996 Agency 

(7508W) 738-R-95-040. 

U.S. GS (Geological Survey). 2012. U.S National Water Quality Assessment Data Warehouse 

http://infotrek.er.usgs.gov/apex/f?p=NAWQA:HOME:0

U.S. National Research Council, 1977. Drinking water and health. Vol. 1. Safe Drinking Water 

Committee. National Academy of Sciences, Washington, DC
9

APPENDIX A

PRZM/EXAMS Inputs and Output File

Table 4 Estimated drinking water concentrations (μg/L)

Scenario Peak 96 hr 21 Day 60 Day 90 Day Yearly

Yearly 

averages

FL Sugarcane 7.89 5.45 3.01 1.86 1.40 0.74 0.59

LA Sugarcane

(U.S. 

Continental) 11.92 8.56 4.06 2.11 1.65 0.99 0.80

LA Sugarcane

(Hawaii)1 23.83 17.12 8.11 4.22 3.30 1.97 1.59

LA Sugarcane

(Hawaii)2 19.37 14.27 6.80 3.68 2.87 1.76 1.35

CA Cotton 12.82 9.18 3.49 1.57 1.20 0.35 0.33

MS Cotton 21.35 15.51 8.30 4.11 3.14 1.08 0.84

NC Cotton 19.63 14.79 7.69 3.88 2.95 0.99 0.88

ND Canola 8.16 5.88 2.74 1.25 0.90 0.30 0.25

1 = Aerial Application

2 = ground application

Example of PRZM/EXAMS Output File

stored as HISugrDW.out

Chemical: Trifluralin

PRZM 

environm

ent: 

LAsugarc

aneSTD.t

xt

modified Tueday, 29 May 2007 at 13:56:00

EXAMS 

environm

ent: 

ir298.exv

modified Tueday, 26 August 2008 at 06:14:08

Metfile: 

w13970.d

vf

modified Tueday, 26 August 2008 at 06:14:50

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 16.86 13.03 7.11 3.58 2.88 1.38

1962 14.03 9.82 6.27 3.43 2.54 1.59

1963 13.50 9.87 3.90 2.33 2.03 1.15
10

1964 19.92 15.83 7.03 3.85 2.98 1.86

1965 21.17 14.72 6.99 3.35 2.60 1.48

1966 14.15 11.32 4.56 2.81 2.56 1.43

1967 26.21 18.30 7.22 3.67 3.11 1.63

1968 13.91 10.00 4.06 2.27 1.74 1.18

1969 13.55 9.52 4.92 3.58 2.85 1.66

1970 19.64 13.81 6.61 3.08 2.61 1.56

1971 13.70 9.60 5.23 3.69 2.85 1.60

1972 13.89 10.96 4.68 2.22 2.56 1.52

1973 19.13 13.58 8.16 4.20 3.31 1.98

1974 13.23 9.31 3.50 2.56 2.06 1.18

1975 13.44 9.73 4.85 2.57 2.35 1.51

1976 13.14 9.73 4.02 1.96 1.91 1.31

1977 24.13 17.26 10.38 5.09 3.89 2.04

1978 24.21 17.96 7.66 3.42 2.54 1.57

1979 17.32 13.14 5.49 3.66 3.05 1.67

1980 14.16 9.84 6.29 4.32 3.61 2.07

1981 13.35 9.95 5.34 2.75 2.10 1.42

1982 13.29 9.42 4.30 2.22 1.79 1.41

1983 16.45 12.27 5.44 3.98 3.22 1.85

1984 13.77 9.70 5.99 3.50 3.05 1.52

1985 15.38 10.73 6.37 3.24 2.78 1.59

1986 13.35 9.66 4.17 2.29 2.06 1.54

1987 15.41 11.66 6.08 3.29 2.45 1.67

1988 19.30 13.83 8.43 4.22 3.22 1.91

1989 13.23 9.53 4.42 3.18 2.72 1.93

1990 16.40 11.61 5.27 2.80 2.20 1.56

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.03 26.21 18.30 10.38 5.09 3.89 2.07

0.06 24.21 17.96 8.43 4.32 3.61 2.04

0.10 24.13 17.26 8.16 4.22 3.31 1.98

0.13 21.17 15.83 7.66 4.20 3.22 1.93

0.16 19.92 14.72 7.22 3.98 3.22 1.91

0.19 19.64 13.83 7.11 3.85 3.11 1.86

0.23 19.30 13.81 7.03 3.69 3.05 1.85

0.26 19.13 13.58 6.99 3.67 3.05 1.67

0.29 17.32 13.14 6.61 3.66 2.98 1.67

0.32 16.86 13.03 6.37 3.58 2.88 1.66

0.35 16.45 12.27 6.29 3.58 2.85 1.63

0.39 16.40 11.66 6.27 3.50 2.85 1.60

0.42 15.41 11.61 6.08 3.43 2.78 1.59

0.45 15.38 11.32 5.99 3.42 2.72 1.59
11

0.48 14.16 10.96 5.49 3.35 2.61 1.57

0.52 14.15 10.73 5.44 3.29 2.60 1.56

0.55 14.03 10.00 5.34 3.24 2.56 1.56

0.58 13.91 9.95 5.27 3.18 2.56 1.54

0.61 13.89 9.87 5.23 3.08 2.54 1.52

0.65 13.77 9.84 4.92 2.81 2.54 1.52

0.68 13.70 9.82 4.85 2.80 2.45 1.51

0.71 13.55 9.73 4.68 2.75 2.35 1.48

0.74 13.50 9.73 4.56 2.57 2.20 1.43

0.77 13.44 9.70 4.42 2.56 2.10 1.42

0.81 13.35 9.66 4.30 2.33 2.06 1.41

0.84 13.35 9.60 4.17 2.29 2.06 1.38

0.87 13.29 9.53 4.06 2.27 2.03 1.31

0.90 13.23 9.52 4.02 2.22 1.91 1.18

0.94 13.23 9.42 3.90 2.22 1.79 1.18

0.97 13.14 9.31 3.50 1.96 1.74 1.15

0.10 23.83 17.12 8.11 4.22 3.30 1.97

Average 

of yearly 

averages:

1.59

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: HISugrDW

Metfile: w13970.dvf

PRZM 

scenario:

LAsugarcaneSTD.txt

EXAMS 

environm

ent file:

ir298.exv

Chemical 

Name:

Triflurali

n

Descripti

on

Variable 

Name

Value Units Comments

Molecula

r weight

mwt 335.28 g/mol

Henry's 

Law 

Const.

henry 1.03E-04 atm-m^3/mol

Vapor 

Pressure

vapr 4.58E-05 torr

Solubility sol 0.4 mg/L

Kd Kd mg/L

Koc Koc 8757.9 mg/L

Photolysi

s half-life

kdp 9.43 days Half-life

Aerobic kbacw 438 days Halfife
12

Aquatic 

Metabolis

m

Anaerobi

c Aquatic 

Metabolis

m

kbacs 68 days Halfife

Aerobic 

Soil 

Metabolis

m

asm 219 days Halfife

Hydrolysi

s:

pH 7 0 days Half-life

Method: CAM 4 integer See PRZM manual

Incorpora

tion 

Depth:

DEPI 5.08 cm

Applicati

on Rate:

TAPP 2.24 kg/ha

Applicati

on 

Efficienc

y:

APPEFF 0.95 fraction

Spray 

Drift

DRFT 0.16 fraction of application rate applied to pond

Applicati

on Date

Date 3-Jan dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 180 days Set to 0 or delete line for single app.

app. rate 

1

apprate kg/ha

Record 

17:

FILTRA

IPSCND 1

UPTKF

Record 

18:

PLVKRT

PLDKRT

FEXTRC 0.5

Flag for 

Index 

Res. Run

IR Reservoir

Flag for 

runoff 

calc.

RUNOFF total none, monthly or total(average of entire run)
13

Example of SCIGROW Output File

 SCIGROW

 VERSION 2.3

 ENVIRONMENTAL FATE AND EFFECTS DIVISION

 OFFICE OF PESTICIDE PROGRAMS

 U.S. ENVIRONMENTAL PROTECTION AGENCY

 SCREENING MODEL

 FOR AQUATIC PESTICIDE EXPOSURE

SciGrow version 2.3

chemical:Trifluralin

time is 7/ 3/2012 9:58:50

------------------------------------------------------------------------

 Application Number of Total Use Koc Soil Aerobic

 rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------------------------------------------------------------

 4.000 2.0 8.000 8.76E+03 169.0

------------------------------------------------------------------------

groundwater screening cond (ppb) = 5.49E-02 

************************************************************************

SciGrow version 2.3

chemical:Trifluralin

time is 7/ 3/2012 9:58:57

------------------------------------------------------------------------

 Application Number of Total Use Koc Soil Aerobic

 rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------------------------------------------------------------

 2.000 1.0 2.000 8.76E+03 169.0

------------------------------------------------------------------------

groundwater screening cond (ppb) = 1.37E-02 

************************************************************************

SciGrow version 2.3

chemical:Trifluralin

time is 7/ 3/2012 9:59: 2

------------------------------------------------------------------------

 Application Number of Total Use Koc Soil Aerobic

 rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------------------------------------------------------------

 1.250 1.0 1.250 8.76E+03 169.0

------------------------------------------------------------------------

groundwater screening cond (ppb) = 8.58E-03 

************************************************************************