2

assessment was performed for parent, zoxamide as well as its total toxic residue (TTR; i.e. parent 

plus RH-150721, RH-24549, RH-141288, RH-129151 and RH-139432), recommended by the 

Metabolism Assessment Review Committee (MARC) of the Heath Effects Division (US EPA 

2000a; DP270797). The surface water and groundwater modeling was conducted according to 

labeled use directions which listed a maximum annual application rate of 1.33 lbs. a.i./A.

Modeling for the foliar application used the coupled models PRZM and EXAMS for surface 

water and SCI-GROW for ground water. For surface water, GA Onion scenario was simulated 

for aerial application based on the highest estimated environmental concentrations (EECs) 

determined in the recent ecological risk assessment for zoxamide (US EPA 2013: DP 411544). 

In addition, the PRZM-GW model (USEPA, 2012a) was used in determining groundwater 

EDWCs for zoxamide and its total toxic residue. Since this is the first time PRZM-GW modeling 

was performed for zoxamide, the highest application rate for all currently registered zoxamide

uses, [1.6 lbs a.i/A for use on grape and potato based on the Gavel® 80WP label (EPA Reg. 

No.10163-6413)] was used to determine drinking water exposure in groundwater. 

Recommended EDWCs for zoxamide and total toxic residue of zoxamide in surface water and 

groundwater are summarized in Table 1. For surface water, the EDWCs of zoxamide for onions, 

garlic and shallots (Table 2) did not exceed the recommended peak (acute) concentration of 

17.55 μg/L, annual mean (non-cancer chronic) concentration of 2.49 μg/L, and the 30 year 

annual average concentration (cancer chronic) of 0.91 μg/L for use on grape reported in the 

previous drinking water assessment (US EPA, 2000; DP 266174+). Also, the TTR EDWCs for 

onions, garlic and shallots did not exceed the recommended peak (acute) concentration of 83.30

μg/L, annual mean (non-cancer chronic) concentration of 54.48 μg/L, and the 30 year annual 

average concentration (cancer chronic) of 22.84 μg/L for use on grape reported in the previous 

drinking water assessment (US EPA, 2000; DP 266174+). However, the previously 

recommended EDWCs were based on 0.89 PCA (Percent Cropped Area) factor and were revised 

using the current PCA of 0.91 for agricultural uses according to recently implemented revised 

guidance for PCA (USEPA 2012b). 

Table 1. Recommended EDWCs Based on Parent and Total Toxic Residues of 

Zoxamide 

Drinking Water 

Source Crop Scenario Peak Exposure(μg/L)

Annual Mean

Exposure (μg/L) 

Average Annual

Exposure (μg/L)

Zoxamide (Parent only)

Surface water NY Grape STD 

Scenario1

17.55 2.49 0.91

Ground water FL Citrus Scenario2 1.83E-03 NA 6.84E-04

Total Toxic Residue (Parent +RH-150721, RH-24549, RH-141288, RH-129151 and RH-139432)

Surface water NY Grape STD 

Scenario1

81.3 54.48 22.84

Ground water WI corn Scenario2 83.5 NA 65.8

1 Reported EDWCs generated using PRZM/EXAMS model for aerial application (US EPA 2000) and 

these values are revised with recommended current PCA factor of 0.91. 

2 Highest EDWCs generated using PRZM-GW model based on 1.60 lbs a.i/A for grape and potato 

[Gavel 80 WP (EPA Reg. No.10163-6413)]
3

The estimated PZRM-GW ground water acute concentration of 1.83E-03 μg/L for parent and 

chronic concentration of 6.84E-04 μg/L are lower than the previously recommended 

concentration of 6.40E-02 μg/L for both acute and chronic values for grape and potato (US EPA, 

2000; D266174+). Therefore, the current EDWCs did not supersede the previously 

recommended EDWCs for groundwater for zoxamide. However, PZRM-GW ground water acute 

concentration of 83.5 μg/L and chronic concentration of 65.8 μg/L for TTR are higher than the 

previously recommended concentration of 2.07 μg/L for both acute and chronic values for grape

and potato (US EPA, 2000; D266174+). Therefore, the current EDWCs supersede the previously 

recommended EDWCs for groundwater for the total toxic residue of zoxamide.

Table 2. Maximum EDWCs Based on Parent and Total Toxic Residues of 

Zoxamide on onions (Dry Bulb), Garlic and Shallots Uses

Drinking Water 

Source Crop Scenario Peak Exposure(μg/L)

Annual Mean

Exposure (μg/L) 

Average Annual

Exposure (μg/L)

Zoxamide (Parent only)

Surface water GA Onion STD 

Scenario1

6.47 0.47 0.33

Ground water FL Citrus Scenario2 1.83E-03 NA 6.84E-04

Generic Scenario3 5.15-E-02 5.15-E-02 5.15-E-02

Total Toxic Residue (Parent +RH-150721, RH-24549, RH-141288, RH-129151 and RH-139432)

Surface water GA Onion STD 

Scenario1

10.09 1.20 0.81

Ground water WI corn Scenario2 83.5 NA 65.8

Generic Scenario3 4.52E-01 4.52E-01 4.52E-01

1 PCA of 0.91 adjusted EDWCs generated using PRZM/EXAMS model for aerial application 2 Highest EDWCs generated using PRZM-GW model based on 1.60 lbs a.i/A for grape and potato 

[Gavel 80 WP (EPA Reg. No.10163-6413)] 3 EDWCs generated using SCIGROW model and represent both acute and chronic 

Drinking Water Exposure Modeling

Surface Water

A Tier II drinking water assessment was performed using PRZM (v3.12.2)/EXAMS (v. 

2.98.04.06) modeling with the index reservoir scenario. The EDWCs were generated for parent 

as well as its total toxic residue (TTR) in which zoxamide and five major degradates, RH150721, RH-24549, RH-141288, RH-129151, and RH-139432 were used for modeling as 

recommended by the MARC (US EPA 2000). The EDWCs were calculated for the scenario 

yielding the highest EECs (i.e., GA onion, aerial application) for the ecological risk assessment 

(US EPA 2013b). 

The Pesticide Root Zone Model, (PRZM, Carsel et al. 1997) and the Exposure Analysis 

Modeling System (EXAMS, Burns 2000) were used in tandem to generate aquatic EECs. PRZM 

(3.12.2 dated May 12, 2005) simulates fate and transport on the agricultural/range land whereas 
4

EXAMS (2.98.04.06, dated April 25, 2005) simulates the fate and resulting daily concentrations 

in the water body. Simulations are carried out with the linkage program shell, PE5V01.pl (dated 

November 15, 2006), which incorporates the standard non-agricultural scenarios developed by 

EFED. The PRZM model simulates pesticide movement and transformation from crop 

application through soil residue processes. 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. Standard 

percent cropped areas (PCA) were used for proposed uses as estimates of the extent of watershed 

on which crops are grown. The default PCA of 0.91 was used for the proposed uses because 

currently zoxamide can be used in agricultural settings only (USEPA 2012b). Simulations are 

run for multiple (usually 30) years, and the EDWCs represent peak values that are expected once 

every ten years based on the thirty years of daily values generated during the simulation. 

Additional information on these models can be found at: 

http://www.epa.gov/oppefed1/models/water /index.htm.

This drinking water assessment was performed for TTR (parent plus RH-150721, RH-24549, 

RH-141288, RH-129151 and RH-139432), recommended by the Metabolism Assessment 

Review Committee (MARC) of the Heath Effects Division (US EPA 2000a; DP270797). The 

percent of degradates related to drinking water concern were incorporated into DT50s calculations

for fate studies. Estimated DT50s can be found in Appendix A. PRZM/EXAMS input 

parameters are shown in Table 3, and EDWCs are provided in Table 2. Sample outputs and 

results of PRZM/EXAMS modeling are provided in Appendix B. 

Table 3. PRZM/EXAMS Chemical Specific Input Parameters for Zoxamide and Total 

Toxic Residues of Zoxamide

Parameter Input Value and Unit Source/Comments

Inputs applied for both Parent Zoxamide and Total Toxic Residues (TTR)

Scenario GA Onion Highest EECs observed in the 

Ecological Risk Assessment

Number of Application x maximum 

single application rate 7 x 0.17 lbs AI/A (0.19kg ai/ha)

1 x 0.14 lbs ai/A (0.16 kg ai/ha)

Gavel® 75DF Labels

(EPA Est. No. 003125-FRA-001

(EPA Reg. No. 10163-6414)

Method of application

CAM = 2 Foliar Spray 

Product Label as above

Maximum number of applications 8 (Foliar) Product Label as above

Application efficiency 0.95 (Aerial Spray) EFED Model Input Guidance, 

Version 2.1 (2009b) 1

Spray drift 0.135 (Aerial Spray) Spray Drift Guidance (2013)

Application date and minimum 

interval between applications (days)

GAOnion wirrigSTD: April 14 (7) A combination of label directions 

and information related to crop 

profile in current scenario for 

PRZM/EXAM model 

Molecular Weight 336.1 MRID 44731803

Solubility in water 0.681 mg/L (25 oC) MRID 44731803

Vapor pressure 1.0 x 10-7 mm Hg (25 oC) MRID 44731803

Henry’s Law constant 3.26 x 10-11 atm x m3/mol MRID 46515901

The following input parameters are applicable to parent zoxamide only
5

Table 3. PRZM/EXAMS Chemical Specific Input Parameters for Zoxamide and Total 

Toxic Residues of Zoxamide

Parameter Input Value and Unit Source/Comments

Hydrolysis 15.5 day @ pH 4.0

15.7 days @ pH 7.0

8.7 days @ pH 9.0

MRID 44731908

Aquatic photolysis t1/2 (days) 15.7 days MRID 44731911

Aerobic soil metabolism(t1/2)

2 38.7days MRIDs 44731911 and 44731913

Aerobic aquatic metabolism (t1/2) 3 11.8days MRID 44770002

Anaerobic aquatic metabolism (t1/2) 4 29.2 days MRID 44731914

Partition coefficient Koc 1224 mL/g MRID 44731916

The following input parameters are applicable to total toxic residues of zoxamide only

Hydrolysis 566 day @ pH 4.0

661 days @ pH 7.0

114 days @ pH 9.0

MRID 44731908

Aerobic soil metabolism(t1/2)

2 43.5 days MRIDs 4431911 and -4431913

Aerobic aquatic metabolism (t1/2)

3 11.8 days MRID 4477002

Anaerobic aquatic metabolism (t1/2) 4 1286 MRID 44731914

Aquatic photolysis t1/2 (days) 5 268.3 days MRID 44731911

Partition coefficient Koc

6 131 mL/g EPISUITE 1 Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides

(Version 2.1; Oct. 22, 2009)

2

The 90% of the UCL of the mean metabolism half-life of all available half-lives. 3 2

The 90% of the UCL of the mean metabolism half-life of all available half-lives. No degradate of drinking water concern was 

observed in aerobic aquatic metabolism.

4 2x 14.6 days available anaerobic soil metabolism DT50 5 Estimated DT50 of 268.3 days is based on pH 4 hydrolysis DT50 of 566 days instead of dark control 6 Used EPISUITE Estimated lowest Koc of RH-139432 

Ground Water

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. The SCI-GROW model and user’s manual may also be downloaded from the 

EPA Water Models web-page (http://www.epa.gov/oppefed1/models/water/#scigrow). A 

summary of the model input parameter values used in the SCI-GROW model is listed in Table 4. 

SCI-GROW EDWCs are presented in Table 2. 

Table. 4. SCI-GROW Input Parameters for zoxamide and Total Toxic Residue of 

Zoxamide 

Model Input Variable Input Values Sources Comments

The following input parameters are applicable to parent zoxamide

Application Rate 0.17 lb. a.i./acre

(EPA Reg. No. 

10163-6414)

---

Number of Applications 8

Product Label as 

above

---

The following input parameters are applicable to parent zoxamide
6

Table. 4. SCI-GROW Input Parameters for zoxamide and Total Toxic Residue of 

Zoxamide 

Model Input Variable Input Values Sources Comments

Aerobic Soil Metabolism halflife 40.3 daysMRIDs 44731911 

and -44731913

Mean value

Koc (the median value of all 

available Kocs, MRIDs) 1294

Median value

The following input parameters are applicable to total toxic residues of zoxamide only

Aerobic Soil Metabolism halflife 37.8 daysMRIDs 4431911 

and -44731913

Mean value

Koc 131 mL/g EPISUITE Lowest Koc derived from 

RH-139432

In addition, Tier 1 groundwater EDWCs for zoxamide and its total toxic residue, resulting from 

its use on grape for its higher application rate of 1.60 lbs a.i./A were estimated using the PRZMGW model (USEPA, 2012c), with the GW-GUI (Graphical User Interface, version 1.0, August 

31, 2012a). PRZM-GW is a one-dimensional, finite-difference model that estimates the 

concentrations of pesticides in groundwater. It accounts for pesticide fate in the crop root zone 

by simulating pesticide transport and degradation through the soil profile after a pesticide is 

applied to an agricultural field. PRZM-GW permits the assessment of multiple years of pesticide 

application (up to 100 years) on a single site. Six standard scenarios, each representing a 

different region known to be vulnerable to groundwater contamination, are available for use with 

PRZM-GW for risk assessment purposes. In PRZM-GW simulations, each of these standard 

scenarios was used. PRZM-GW output values represent pesticide concentrations in a vulnerable 

groundwater supply that is located directly beneath a rural agricultural field following many 

years of pesticide application. Breakthroughs were observed in all modeled scenarios. A 

summary of the model input parameter values used in PRZM-GW model is listed in Table 5. 

PRZM-GW values are presented in Table 6. A sample output of PRZM-GW model can be found in 

Appendix B. 

Table 5. PRZM-GW Input Parameters1 for Zoxamide and Total Toxic Residues of 

Zoxamide 

Variable Name Data Value

Data Source

MRID(s) Comment

Application Method Aerial (Grape and potato ) Current labels

EPA Reg# 10163-

6413

Application Rate 

(lbs. a.i./acre) [kg/ha]

0.2 [0.224] (Grape and potato) Current labels

EPA Reg# 10163-

6413

Application Frequency Grape and Potato: 8 times/year Current labels

EPA Reg# 10163-

6413

Application Interval (days) 7-14 Current labels

EPA Reg# 10163-

6413

The following input parameters are applicable to parent zoxamide
7

Table 5. PRZM-GW Input Parameters1 for Zoxamide and Total Toxic Residues of 

Zoxamide 

Variable Name Data Value

Data Source

MRID(s) Comment

Hydrolysis, DT50 (Days) 15.7 @pH 7.0 MRID 44731908 ---

Aerobic Soil Metabolism

DT50 (Days) 38.7 days

MRIDs.: 

44731911 and 

44731913

The 90% of the upper 

confidence limit (UCL)

of the mean metabolism 

half-life.

Koc (mL/goc) 1224 MRIDs:

44731916 Average Koc

The following input parameters are applicable to total toxic residues of zoxamide 

Hydrolysis, DT50 (Days) 661 @pH 7.0 MRID 44731908 ---

Aerobic Soil Metabolism 

DT50 (Days) 43.5 days

MRIDs.: 

44731911 and 

44731913

The 90% of the upper 

confidence limit (UCL)

of the mean metabolism 

half-life.

Koc (mL/goc) 131 EPISUITE Lowest Koc derived 

from RH-139432 1 EFED input parameter guidance: http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_input_guidance.htm

Table 6. PRZM-GW results based on Zoxamide uses on Grape and Oninos, Garlic and Shallots.

Crop Scenario

Highest

Daily

Value (μg/L)

Average (μg/L)

Average Simulation 

Breakthrough Time 

(days)

Zoxamide (Parent only)

Grape and Potato

(0.2 lbs a.i./A x 8 

applications)

Delmarva sweet corn 0.000193 0.000171 10320

FL citrus 0.00221 0.000831 10243

FL potato 1.21E-10 2.25E-11 25923

GA peanut 5.74E-11 1.42E-11 20939

NC cotton 5.35E-08 6.00E-09 11089

WI corn 2.32E-06 9.03E-07

Total Toxic Residue (Parent +RH-150721, RH-24549, RH-141288, RH-129151 and RH-139432)

Grape and Potato

(0.2 lbs a.i./A x 8 

applications)

Delmarva sweet corn 43.2 31.3 1298

FL citrus 58.1 45.8 1308

FL potato 0.71 0.30 3002

GA peanut 7.69 6.64 3117

NC cotton 17.2 11.4 2113

WI corn 83.51 65.81 2962 1 Bolded values are the highest EDWCs for parent and total toxic residue.
8

Monitoring Data

The U.S. Geological Survey’s National Water Quality Assessment program (NAWQA) has 

conducted some monitoring for zoxamide1

. Six surface water samples from California and six 

sediment samples from Georgia were analyzed for zoxamide. Zoxamide was not detected in any 

of the surface water (limit of quantitation (LOQ) was 3.5 ng/L-water) and sediment (LOQ was 

1.1 μg/Kg-sediment) samples. However, NAWQA monitoring data were not targeted 

specifically to zoxamide use areas or during times of known zoxamide use; thus, the dataset 

likely does not reflect peak zoxamide concentrations that may occur in surface waters when 

runoff events occur shortly after zoxamide is applied. Zoxamide was not included as an analyte 

for groundwater monitoring in the NAWQA program. 

Monitoring data for surface water, groundwater, and sediment from the California Department of 

Pesticide Regulation (CDPR) were searched on November 26, 20132. Zoxamide monitoring data 

were not available.

Uncertainties

The lack of environmental fate data for the major degradates of zoxamide is an uncertainty in 

this assessment. To address this uncertainty, Tier II modeling (PRZM/EXAMS) based on the 

TTR of zoxamide (zoxamide plus degradation products RH-150721, RH-24549, RH-141288, 

RH-129151, and RH-139432) was used to determine EDWCs. Although the persistence of the 

zoxamide residues was estimated from registrant submitted environmental fate data, the mobility 

of zoxamide residues was estimated using the EPISUITE, which is a Windows®-based suite of 

physical/chemical property and environmental fate estimation programs developed by the EPA’s 

Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC).

Conclusions

This assessment provides estimated drinking water concentrations (EDWCs) of zoxamide and its 

major metabolites, RH-150721, RH-24549, RH-141288, RH-129151 and RH-139432 in surface 

water and groundwater in support of human health risk assessment for use of zoxamide on 

onions, shallot and garlic The surface water and groundwater modeling were conducted 

according to a label-recommended maximum annual application rate of 1.33 lbs. a.i./A for foliar 

application using the coupled models PRZM and EXAMS for surface water and SCI-GROW for 

ground water. In addition, the PRZM-GW model was used in determining groundwater EDWCs 

for zoxamide and its total toxic residues. For surface and groundwater, the EDWCs of zoxamide 

and TTR did not exceed the recommended (US EPA 2000b) peak (acute), annual mean (noncancer chronic), and the 30 year annual average concentrations (cancer chronic), except in the 

PRZM-GW simulated concentrations for TTR of zoxamide. Recommended acute and chronic 

zoxamide TTR concentrations are 83.5 μg/L and 65.8 μg/L for ground water, respectively. 

Zoxamide was not detected in any of the surface water (limit of quantitation (LOQ) was 3.5 

ng/L-water) and sediment (LOQ was 1.1 μg/Kg-sediment) samples collected for NAWQA. 

However, NAWQA monitoring data were not targeted specifically to zoxamide use areas or 

 1 http://water.usgs.gov/nawqa/pnsp/ 2 http://www.cdpr.ca.gov/docs/emon/ehap.htm
9

during times of known zoxamide use. Zoxamide was not included as an analyte for groundwater 

monitoring in the NAWQA program. 
10

References

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

US EPA, 2000a. PP#9F05058; Zoxamide in/on Potato and Grapes. Conclusions of the 

11/14/2000 Meeting of the Metabolism Assessment Review Committee. ( D270797) 

US EPA, 2000b. Estimated Drinking Water Concentrations for zoxamide and its degradation 

products December 06, 2000. (D266174+) 

USEPA. 2009b. 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. 

USEPA. 2010. Water Models. U.S. Environmental Protection Agency, Pesticides: Science and 

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

US EPA. 2012a. Memorandum: Approval of PRZM-GW for use of Drinking Water Exposure 

Assessment. Environmental Fate and Effects Division, Office of Chemical Safety and 

Pollution Prevention. U. S. Environmental Protection Agency.

US EPA. 2012b. Development and Use of Percent Cropped Area and Percent Turf Area 

Adjustment Factors in Drinking Water Exposure Assessments: 2012 Update 

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

US EPA. 2013a. Zoxamide: Ecological Risk Assessment to Support the Proposed New Uses on 

Onions (Dry Bulb), Garlic, and Shallots. Environmental Fate and Effects Division, Office 

of Chemical Safety and Pollution Prevention. U. S. Environmental Protection Agency.

December 12, 2013. (DP 411544)

US EPA. 2013b. Guidance on Modeling offsite deposition of pesticides via spray drift for 

Ecological and Drinking Water Assessments. Environmental Fate and Effects Division, 

Office of Chemical Safety and Pollution Prevention. U. S. Environmental Protection 

Agency. December 20, 2013. 
11

APPENDIX A

Hydorlysis
12

Aquatic Photolysis
13

Aerobic Soil Metabolism

Aerobic Aquatic Metabolism
14

No degradate of drinking water concern formed in aerobic aquatic metabolism study.

Anaerobic Soil Metabolism
15

APPENDIX B

An example output of PRZM/EXAMS modeling.

stored as GADWTTRA.out

Chemical: Zoxamide TTR

PRZM environment: GAOnion_WirrigSTD.txt, modified Tueday, 29 May 2007 at 12:54:42

EXAMS environment: pond298.exv, modified Tueday, 26 August 2008 at 05:14:08

Metfile: w03822.dvf, modified Tueday, 26 August 2008 at 05:14:10, 

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 8.53 7.77 6.56 5.85 4.49 1.14

1962 4.96 4.60 4.05 3.55 2.76 0.70

1963 9.06 8.22 7.16 4.97 3.80 0.98

1964 12.02 11.18 8.88 5.59 4.04 1.02

1965 6.23 5.60 4.66 3.63 2.84 0.73

1966 8.27 7.80 6.91 4.81 3.71 0.95

1967 6.08 5.50 4.79 3.64 2.80 0.72

1968 7.67 7.04 6.47 4.65 3.57 0.91

1969 21.59 19.69 14.76 8.39 6.19 1.58

1970 8.55 7.77 5.69 3.91 3.03 0.78

1971 6.70 6.11 5.42 4.36 3.28 0.83

1972 6.64 6.07 5.34 4.17 3.25 0.83

1973 5.41 5.05 4.55 3.85 2.96 0.75

1974 13.66 12.30 9.34 6.94 5.40 1.38

1975 7.85 7.27 6.30 5.81 4.36 1.10

1976 10.62 9.88 8.64 7.01 5.23 1.33

1977 4.38 3.96 3.60 3.06 2.29 0.58

1978 5.33 4.82 4.46 3.68 2.79 0.71

1979 8.16 7.53 6.48 5.31 4.02 1.02

1980 6.82 6.20 5.37 3.97 3.06 0.77

1981 4.96 4.55 4.23 3.32 2.48 0.63

1982 7.75 7.21 5.63 4.91 3.76 0.96

1983 7.92 7.39 6.64 4.91 3.63 0.91

1984 9.96 9.03 6.59 5.43 4.08 1.04

1985 5.34 4.68 3.83 3.24 2.54 0.65

1986 4.71 4.25 3.93 3.05 2.31 0.58

1987 11.43 10.30 7.98 5.06 3.79 0.96

1988 6.66 6.06 5.32 4.46 3.35 0.85

1989 4.65 4.23 3.91 3.11 2.34 0.59

1990 6.22 5.76 4.93 3.93 2.94 0.74
16

Sorted results

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

0.03 21.59 19.69 14.76 8.39 6.19 1.58

0.06 13.66 12.30 9.34 7.01 5.40 1.38

0.10 12.02 11.18 8.88 6.94 5.23 1.33

0.13 11.43 10.30 8.64 5.85 4.49 1.14

0.16 10.62 9.88 7.98 5.81 4.36 1.10

0.19 9.96 9.03 7.16 5.59 4.08 1.04

0.23 9.06 8.22 6.91 5.43 4.04 1.02

0.26 8.55 7.80 6.64 5.31 4.02 1.02

0.29 8.53 7.77 6.59 5.06 3.80 0.98

0.32 8.27 7.77 6.56 4.97 3.79 0.96

0.35 8.16 7.53 6.48 4.91 3.76 0.96

0.39 7.92 7.39 6.47 4.91 3.71 0.95

0.42 7.85 7.27 6.30 4.81 3.63 0.91

0.45 7.75 7.21 5.69 4.65 3.57 0.91

0.48 7.67 7.04 5.63 4.46 3.35 0.85

0.52 6.82 6.20 5.42 4.36 3.28 0.83

0.55 6.70 6.11 5.37 4.17 3.25 0.83

0.58 6.66 6.07 5.34 3.97 3.06 0.78

0.61 6.64 6.06 5.32 3.93 3.03 0.77

0.65 6.23 5.76 4.93 3.91 2.96 0.75

0.68 6.22 5.60 4.79 3.85 2.94 0.74

0.71 6.08 5.50 4.66 3.68 2.84 0.73

0.74 5.41 5.05 4.55 3.64 2.80 0.72

0.77 5.34 4.82 4.46 3.63 2.79 0.71

0.81 5.33 4.68 4.23 3.55 2.76 0.70

0.84 4.96 4.60 4.05 3.32 2.54 0.65

0.87 4.96 4.55 3.93 3.24 2.48 0.63

0.90 4.71 4.25 3.91 3.11 2.34 0.59

0.94 4.65 4.23 3.83 3.06 2.31 0.58

0.97 4.38 3.96 3.60 3.05 2.29 0.58

0.10 11.96 11.09 8.86 6.83 5.15 1.31

Average 

of yearly 

averages

:

0.89

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: GADWTTRA

Metfile: w03822.dvf
17

PRZM 

scenario:

GAOnion_WirrigSTD.txt

EXAMS 

environ

ment 

file:

pond298.exv

Chemica

l Name:

Zoxamid

e

Descripti

on

Variable 

Name

Value Units Comments

Molecul

ar 

weight

mwt 336.1 g/mol

Henry's 

Law 

Const.

henry 3.26E-11 atm-m^3/mol

Vapor 

Pressure

vapr 1.00E-07 torr

Solubilit

y

sol 0.681 mg/L

Kd Kd mg/L

Koc Koc 14.3 mg/L

Photolys

is halflife

kdp 268.3 days Half-life

Aerobic 

Aquatic 

Metaboli

sm

kbacw 11.8 days Halfife

Anaerob

ic 

Aquatic 

Metaboli

sm

kbacs 1286 days Halfife

Aerobic 

Soil 

Metaboli

sm

asm 43.5 days Halfife

Hydrolys

is:

pH 4 566 days Half-life

Hydrolys

is:

pH 7 661 days Half-life

Hydrolys

is:

pH 9 114 days Half-life

Method: CAM 2 integer See PRZM manual

Incorpor

ation 

Depth:

DEPI cm
18

Applicati

on Rate:

TAPP 0.19 kg/ha

Applicati

on 

Efficienc

y:

APPEFF 0.95 fraction

Spray 

Drift

DRFT 0.135 fraction of application rate applied to pond

Applicati

on Date

Date 14-04 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 

1

interval 7 days Set to 0 or delete line for single app.

app. rate 

1

apprate 0.19 kg/ha

Interval 

2

interval 7 days Set to 0 or delete line for single app.

app. rate 

2

apprate 0.19 kg/ha

Interval 

3

interval 7 days Set to 0 or delete line for single app.

app. rate 

3

apprate 0.19 kg/ha

Interval 

4

interval 7 days Set to 0 or delete line for single app.

app. rate 

4

apprate 0.19 kg/ha

Interval 

5

interval 7 days Set to 0 or delete line for single app.

app. rate 

5

apprate 0.19 kg/ha

Interval 

6

interval 7 days Set to 0 or delete line for single app.

app. rate 

6

apprate 0.19 kg/ha

Interval 

7

interval 7 days Set to 0 or delete line for single app.

app. rate 

7

apprate 0.16 kg/ha

Record 

17:

FILTRA

IPSCND 1

UPTKF

Record 

18:

PLVKRT

PLDKRT

FEXTRC 0.5

Flag for IR EPA 
19

Index 

Res. Run

Pond

Flag for 

runoff 

calc.

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

Input and output of SCIGROW modeling.

SciGrow version 2.3

chemical:Zoxamide

time is 1/ 3/2014 9:37: 6

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

 Application Number of Total Use Koc Soil Aerobic

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

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

 0.170 8.0 1.360 1.29E+03 37.8

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

groundwater screening cond (ppb) = 5.15E-02 

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

SciGrow version 2.3

chemical:Zoxamide

time is 1/ 3/2014 9:39:23

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

 Application Number of Total Use Koc Soil Aerobic

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

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

 0.170 8.0 1.360 1.31E+02 40.3

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

groundwater screening cond (ppb) = 4.52E-01 

************************************************************************
20

Example Output of PRZM-GW modeling