1

MEMORANDUM

DATE: September 30, 2014

SUBJECT: Drinking Water Exposure Assessment for the Section 3 New Use of Metconazole 

on Pea and Bean (Dried Shelled, Subgroup 6C), and Sunflower (Subgroup 20B) 

TO: Laura Nollen, Risk Manager Reviewer

Barbara Madden, Minor Use Team Leader

Marion Johnson, Branch Chief

Risk Integration Minor Use, and Emergency Response Branch

Registration Division (7505P)

Erin Malone, Risk Manager Reviewer

Hope Johnson, Product Manager Team 21

Cynthia Giles-Parker, Branch Chief

Fungicide Branch

Registration Division (7505P)

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

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

APPROVED

BY: Sujatha Sankula, Ph.D. Branch Chief

Meghan Radtke, Ph.D., Acting RAPL

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

Executive Summary

This memo summarizes the estimated drinking water concentrations (EDWCs) of metconazole

(5-[(4-Chlorophenyl) methyl]-2,2-dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)cyclopentanol]) in 

surface water and groundwater in support of the proposed Section 3 new uses. The Interregional 

Research Project Number 4 (IR-4) submitted a tolerance petition for metconazole new uses on

pea/bean (dried shelled) and sunflower. Foliar spray applications (aerial and ground boom) are 

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

PC Code: 125619

DP Barcode: D418674
2

being proposed for the new uses. The IR-4 also revised existing crop groupings by converting 

stone fruit Group 12 to stone fruit Group 12-12, nut tree Group 12 to nut tree Group 14-12 and 

the expansion from canola seed to rapeseed Subgroup 20A. Since there are no changes in 

application rates and methods for the revised crop groupings, previous drinking water 

assessments (DWAs) fulfill the requirement for refining EDWCs for these crops (stone fruit and 

nut tree nut – USEPA 2007, D340378; canola – USEPA 2008, D350276).

Metconazole parent is the only residue of concern considered in the drinking water assessment. 

No degradates of metconazole were included based on the recommendation from the Residues of 

Concern Knowledgebase Subcommittee (ROCKS) of the Health Effects Division (HED) 

(USEPA, 2008, D348234). 

For surface water, the modeled EDWCs for pea/bean (dried shelled) and sunflower for this 

assessment did not exceed the previously recommended concentrations of 45.5 μg/L (peak) and 

22.8 μg/L (30 year annual average concentration) based on the turf scenario (USEPA 2007, 

D340378) as well as 38.7 μg/L (annual mean concentration) based on the cranberry scenario 

(USEPA 2010, D380513). However, the previously estimated EDWCs for cranberry use were 

based on a 0.87 PCA (Percent Cropped Area) factor. Recently, EFED implemented a revised

guidance for PCA (USEPA 2014). Since metconazole can be used in agricultural and nonagricultural settings, a PCA factor of 1.0 was used to revise the previously estimated surface 

water EDWCs based on cranberry use. Revised peak EDWC of 49.5 μg/L from cranberry use 

exceeded previously recommended EDWC of 45.5 μg/L for turf use. Therefore, the revised 

recommended EDWCs are 49.5 μg/L for peak and 43.9 μg/L for annual mean concentrations 

derived from cranberry scenario. The recommended annual average concentration of 22.8 μg/L 

has not been revised because the PCA factor of 1.0 remains unchanged for turf.

This is the first time the PRZM-GW model has been used in estimating metconazole EDWCs for 

groundwater since the inception of the model in 2012. The highest application rate of 0.60 lbs 

a.i./A for turf was modeled in estimating metconazole EDWCs for groundwater. Since 

application rates for proposed uses are lower than turf, no additional modeling for PRZM-GW 

modeling is warranted at this time. The estimated PRZM-GW groundwater acute concentration 

of 51.8 μg/L and chronic concentration of 20.0 μg/L are higher than the previously

recommended concentration of 0.38 μg/L for turf (USEPA 2007, D340378). Therefore, the 

current EDWCs supersede the previously recommended EDWCs for groundwater. The revised 

recommended EDWCs for both surface water and groundwater for use in HED’s human health 

dietary risk assessment are summarized in Table 1. 

Table 1. Recommended EDWCs for the Proposed Uses of Metconazole for Drinking Water 

Sources

Drinking Water 

Source Crop Scenario (Model)

Peak 

Exposure

(Acute)

(μg/L)

Annual Mean 

Exposure 

(Non-Cancer

Chronic)

(μg/L)

30-year Mean 

Exposure 

(Cancer 

Chronic)

(μg/L) 

Surface Water Turf 45.5 31.3 22.81

Cranberry 49.61

43.9,1,2 NA3

Groundwater WI Central Sand Scenario 51.8,1,4 NA3

20.0,1,4

1 Bolded values are the recommended EDWCs for surface water and groundwater for metconazole uses
3

Table 1. Recommended EDWCs for the Proposed Uses of Metconazole for Drinking Water 

Sources

Drinking Water 

Source Crop Scenario (Model)

Peak 

Exposure

(Acute)

(μg/L)

Annual Mean 

Exposure 

(Non-Cancer

Chronic)

(μg/L)

30-year Mean 

Exposure 

(Cancer 

Chronic)

(μg/L) 

2 The provisional cranberry scenario is applicable for a year simulation only.

3 Not applicable 4

PRZM-GW model was used to reassess groundwater EDWCs for turf use, which has the highest the 

highest application rate of 0.6 lbs a.i/A for metconazole; groundwater EDWCs are based on a PRZM-GW 100 years 

simulation

Proposed Use

Metconazole is a broad-spectrum systemic triazole fungicide that can be applied as a foliar spray

via ground and aerial application methods. The IR-4 and Valent Corporation are seeking 

registration of two new uses and tolerances for revised crop groups (Table 2). According to the 

proposed label (Metconazole 50WDG Fungicide), metconazole can be applied at a maximum 

application rate/year of 0.125-0.44 lb a.i./A via ground and aerial application methods. Two of 

the proposed uses have not been considered previously in drinking water assessments. These 

include uses on pea/bean (dried shelled) and sunflower. Since there are no changes in application 

rates and methods for the revised crop groupings, previous DWAs conducted for various crops

including stone fruit and tree nut (USEPA 2007, D340378) and canola (USEPA 2008, D350276) 

fulfill the requirement for refining EDWCs for these crops.

Table 2. Proposed New Uses and Conversion of Old Crop Groups to New Crop Groups for 

Metconazole

Use Site

Single App. 

Rate

(lbs a.i./A)

# of 

App

Annual

App. Rate

(lbs 

a.i./A)

Retreat

ment 

Interval 

(days)

PHI Application Type EPA Reg # 

Comments/restrictions

Proposed New Uses 

Dried Shelled 

Pea and bean 

except soybean

(Subgroup 6C)

0.08-0.125 2 0.25 7-10 21 Aerial and Ground 

boom

59639-147

Sunflower 

(Subgroup 20B) 0.078-0.125 2 0.25 7-14 21 Aerial and Ground boom

59639-147

Crop Group Expansion

Canola 

[Rapeseed 

(Subgroup 

20A)]

0.0625-

0.125 1 0.125 -- 35 Aerial 59639-147

One application per year

Conversion of old crop group to new crop group
4

Table 2. Proposed New Uses and Conversion of Old Crop Groups to New Crop Groups for 

Metconazole

Use Site

Single App. 

Rate

(lbs a.i./A)

# of 

App

Annual

App. Rate

(lbs 

a.i./A)

Retreat

ment 

Interval 

(days)

PHI Application Type EPA Reg # 

Comments/restrictions

Stone Fruit 

(Group 12-12) 0.11-0.125 3 0.375 7-14 14 Aerial 59639-147Maximum two sequential applications

Tree Nut 

(Group 14-12 0.078-0.11 4 0.44 7-14 25 Aerial 59639-147Maximum two sequential applications

Residues of Concern

Three degradates were observed at greater than 10% of the applied dose in laboratory fate 

studies: M30, hydroxymetconazole, and M13. However, the Residues of Concern 

Knowledgebase Subcommittee (ROCKS) reported that the residue of concern for metconazole in 

drinking water is the parent only (USEPA 2008, D348234). Degradates were excluded in the 

DWA. A detailed rationale for excluding several metconazole metabolites is included in the 

previous DWA (USEPA 2010, D375778+). 

Modeling Approach and Input Parameters

Models

Surface Water 

The Surface Water Concentration Calculator (SWCC v 1.106) model1 was used to generate 

EDWCs for the Tier II aquatic exposure assessment. The SWCC is a graphical user interface that 

runs the Pesticide Root Zone Model (PRZM, v 5, November 15, 2006) and the Variable Volume 

Water Body Model (VVWM, 3/6/2014) (USEPA, 2006b). 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. The default PCA of 1.0

was used for the proposed uses because metconazole can be used in both agricultural and nonagricultural settings (USEPA 2012).

Groundwater 

The Screening Concentration in Ground Water (SCI-GROW v2.3, Jul. 29, 2003) model1is a 

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

groundwater that is used for 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 

 

1

http://www.epa.gov/oppefed1/models/water /index.htm
5

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

concentrations from Prospective Ground Water studies. 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). PCAs are not applicable for the SCIGROW model.

In addition, Tier 1 groundwater EDWCs for metconazole, resulting from its use on turf for the 

highest application rate of 0.60 lbs a.i./A for metconazole was also estimated using the PRZMGW model (USEPA, 2012c), with the GW-GUI (Graphical User Interface, version 1.0, August 

31, 2012). 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. Since there is no breakthrough (i.e., the number of days that it takes 

for the applied chemical to reach the aquifer) observed for 30 years of simulations, extended 

weather files for 100 years were used to determine EDWCs for modeled scenarios. PCAs are not 

applicable for the PRZM-GW model.

Input Parameters

A summary of the model input parameter values used in SWCC, SCI-GROW, and PRZM-GW

models are in Table 3, Table 4, and Table 5, respectively. Input parameters were selected in 

accordance with EFED’s “Guidance for Selecting Input Parameters in Modeling the 

Environmental Fate and Transport of Pesticides,” Version 2.1 (USEPA 2009). Sample model 

output files are located in Appendix B.

Table 3. SWCC Input Parameters for Metconazole Proposed Uses 

Parameter Input Value and Unit Source Comment

Scenarios for proposed Uses

Pea and Bean (Crop subgroup 6C)

Sunflower (Crop subgroup 20B)

MIbeanSTD

NDCanolaSTD1

N/A2

All available scenarios for 

each use

Maximum Single 

Application Rate lbs a.i./A

(Number of Application/year)

Pea and Beans: 0.125 (2)

Sunflower: 0.125 (2)

Proposed labels

EPA Reg. No. 

59639-147

Label directions

Initial Application Date Pea and Beans: August 24

Pea and Beans: July 20

Based on crop scenarios and 

label directions

Application Interval (days)

Pea and Beans: 7

Sunflower: 7

Intervals were selected to 

reflect labeled application 

patterns.

Application Method Aerial and Ground 

Bean/Peas, Sunflower

Proposed labels Label directions

Hydrolysis (t1/2) 0 MRID 46902201 Stable
6

Table 3. SWCC Input Parameters for Metconazole Proposed Uses 

Parameter Input Value and Unit Source Comment

Application efficiency and Spray 

Drift (fraction)

Aerial: 0.95 and 0.135

Ground: 0.99 and 0.066

Input Guidance3

Default

Molecular weight 319.8

MRID 447215-05 Solubility in water 

(pH 7, 20 °C) 18.7 mg/L Solubility of cis isomer4

Vapor pressure 7.8 ×10-8 Torr (mmHg) Vapor Pressure of Cisisomer4

Hydrolysis (t1/2) 0

MRID 46902201 Stable

Aquatic photolysis (t1/2) 72 days MRID 46902202 ---

Aerobic soil metabolism (t1/2) 470.7 days 

MRID 46970901

MRID 46902204

MRID 46808408

Upper 90th %-ile 

confidence bound on the 

mean of six DT50s

Aerobic aquatic metabolism (t1/2) Stable MRID 46902205 Pond water-sediment 

system from Germany

Anaerobic aquatic metabolism 

(t1/2)

Stable MRID 46808410 Greater than 1 year

Partition coefficient Koc 1544 mL/g 

MRID 46808411 Average of four Koc 

1

In absence of sunflower standard scenario, NDCanola STD was used as a surrogate

2 Not Applicable

3 USEPA 2010 http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

4 Since the cis-isomer is the major constituent (85%) of metconazole, physical properties of the cis-isomer were used 

in modeling

Table 4. SCI-GROW (v2.3) Input Parameter Values for Metconazole

Parameter Value Source Comments

Application Rate (lbs 

a.i./acre)

0.125 EPA Reg. No. 59639-

147 Proposed label Number of 

applications 2

EPA Reg. No. 59639-

147

Koc (mL/g) 1213.5 MRID 46808411 Median of four Koc values. 

Aerobic soil 

metabolism t 1⁄2 (days) 261.7

MRID 46970901

MRID 46902204

MRID 46808408

Median of six values. 

Table 5. PRZM-GW Input Parameters1for Metconazloe Uses 

Variable Name Data Value

Data Source

MRID(s) Comment

Application Method Foliar Application EPA Reg. No. 59639-

147

Proposed label

Application Rate 

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

0.125 [0.140] (Pea/Bean and 

Sunflower 0.12 [0.135]

Turf:: 0.12 [0.134]

EPA Reg. No. 59639-

147

Application Frequency Dried bean/peas: 2 time per year 

Sunflower: 2 time per year

EPA Reg. No. 59639- Proposed label
7

Table 5. PRZM-GW Input Parameters1for Metconazloe Uses 

Variable Name Data Value

Data Source

MRID(s) Comment

Turf: 5 times/year US EPA, 2007 Previous DWA

Application Interval (days)

7 (Pea/Bean)

7 Sunflower: 

14 (Turf)

EPA Reg. No. 59639-

147

Proposed label

Proposed Label

Hydrolysis, DT50 (Days) Stable MRID 46902201 ---

Aerobic Soil Metabolism 

DT50 (Days) 470.7 days 

MRID 46970901

MRID 46902204

MRID 46808408

Upper 90th %-ile 

confidence bound 

on the mean of 

six half-lives

Koc (mL/goc) 1544 mL/g 

MRID 46808411 Average of four 

Koc 

1

EFED input parameter guidance: http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_input_guidance.htm

Modeling Results

The estimated metconazole concentrations in surface water used for drinking water are 

summarized in Table 6. The estimated concentrations in surface water for use on sunflower 

resulted in the highest EDWCs at 8.25 μg/L for acute, 6.45 μg/L for annual mean and 5.08 μg/L 

for a 30-year annual average. Acute and chronic estimated metconazole concentrations in surface 

water used for drinking water ranged from 2.89 to 8.25 μg/L. The estimated metconazole

concentrations in groundwater used for drinking water are summarized in Table 7. The estimated 

concentrations in groundwater for use on turf resulted in the highest EDWCs at 51.8 μg/L for 

acute and 20.0 μg/L for a 100-year annual average. The PRZM-GW EDWCs are higher than the 

SCI-GROW EDWCs for the proposed uses and previously recommended EDWC of 0.38 μg/L

for turf uses. Therefore, the current EDWCs supersede the previously recommended EDWCs for 

groundwater. 

Table 6. EDWCs for Metconazole Applications to Various Crops 

Drinking 

Water Source Crop

Crop Scenario

1-in-10-year 

Peak Exposure 

1-in-10-year 

Annual Mean 

Exposure 

30-year Mean 

Exposure 

Concentration (μg/L)

Surface water1

Bean and Pea (dried 

Shelled)

MI Bean STD

7.57(A)2

6.65(G)3

4.45(A)

3.97(G)

3.33(A)

2.89(G)

Sunflower

ND Canola STD 8.25 (A)

6.60 (G)

6.45 (A)

5.04 (G)

5.08 (A)

3.92(G)

1 Surface Water Concentration Calculator was used to determine EDWCs in surface water

2 Aerial application

3 Ground boom application
8

Table 7. Results from PRZM-GW and SCI-GROW Modeling Based on Metconazole Uses on 

Turf and Proposed New Uses

Crop Scenario

Highest

Daily

Value (μg/L)

Average (μg/L)

Average Simulation 

Breakthrough Time 

(days)

Turf1

(0.12 lbs a.i./A x 5 

applications)

FL citrus 29.1 20.2 16195

FL potato 0.04 0.02 34338

GA peanut 6.11 1.8 26738

NC cotton 14.1 9.1 16492

DELMARVA sweet corn 20.0 9.1 19640

WI corn 51.82

20.02

23037

Pea/Bean (Dried 

Shelled) and 

Sunflower

(0.125 lbs a.i./A x 2 

applications)

Generic Scenario30.032 0.032 NA4

1

PRZM-GW modeled the highest metconazole application rate of 0.6 lbs a.i/A for metconazole uses

2 Bolded concentrations are the highest EDWCs determined for groundwater

3 EDWCs are based on SCI-GROW model 

4 Not Applicable

Monitoring Data

Monitoring data for metconazole were available from the United States Geological Survey

(USGS) National Water-Quality Assessment (NAWQA) Program Data Warehouse 

(http://infotrek.er.usgs.gov/nawqa_queries/jsp/swmaster.jsp), searched on September 08, 2014. 

Metconazole was not detected in 75 surface water samples collected from multiple states (CA, 

GA, IA, IN, MO, NE, TX, and WI) at the limit of quantitation (LOQ) of 5.2 ng/L. However, the 

study design of NAWQA is not targeted to account for all metconazole use areas, timing of 

application and other factors which may more accurately represent spatially and temporally 

dependent variables influencing runoff vulnerability. No groundwater and sediment data are 

available at this time.

Drinking Water Treatment

There is no available information on the effects of drinking water treatment on metconazole. 

The EDWCs in this assessment are representative of concentrations in drinking water source 

water (pre-treatment). For surface water, the conceptual model assumes that a pesticide reaches 

surface water via spray drift or surface runoff, it is instantaneously mixed, and concentrations are 

observed in the water body. Metconazole is stable to hydrolysis. Therefore, metconazole will not 

degrade by hydrolysis during the time that elapses from drinking water intake through 

distribution to the first tap. Metconazole is also not sensitive to aqueous photolysis. Therefore, if 

ultraviolet light were used as a means of disinfection, degradation of metconazole would not be 

expected to be significant. Metconazole has a low degradation rate in aerobic aquatic 

environments, therefore, there is not expected to be significant degradation during water 

treatment. The most successful treatment process for removing pesticides from drinking water is 

thought to be treatment with granular activated carbon (GAC), which is only used in larger 
9

drinking water treatment facilities. The ability of GAC to remove pesticides will vary with the 

properties of the chemical, the viability of the biofilm on the GAC, and whether the sorption sites 

on GAC have reached capacity (Badriyha et al., 2003; Zhao et al., 1999). Data on the sorption of 

metconazole to GAC are not available; however, the average Koc (1544 mL/g) value of 

metconazole suggests that there is a potential for removal of metconazole through GAC 

treatment because of its high adsorption coefficient. 
10

Literature Cited

Badriyha, B. N., Ravindran, V., Den, W., & Pirbazari, M. 2003. Bioadsorber efficiency, design, 

and performance forecasting for alachlor removal. Water Research, 37.

USEPA, 2007. Revised Drinking Water Exposure Assessment for Metconazole Based on The 

Proposed Labels of BAS 556 01F, CarambaTM, V-10116 VPP, Metconazole 50 WDG, 

and Metconazole Technical. Environmental Fate and Effects Division. Office of 

Pesticide Programs. United States Environmental Protection Agency (D D340378). 

USEPA, 2008. Updated Drinking Water Exposure Assessment for the use of metconazole in/on 

canola seed. Environmental Fate and Effects Division. Office of Pesticide Programs. 

United States Environmental Protection Agency (D D350276).

USEPA. 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides, Version 2.1. Environmental Fate and Effects Division. 

Office of Pesticide Programs. United States Environmental Protection Agency. Available 

at http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm (Accessed 

February 10, 2013).

USEPA, 2010. Drinking Water Exposure Assessment to Establish Tolerances of Parent 

Metconazole for Tuberous/Corm (Subgroup IC) and Bushberry (Subgroup 13-07C) crops 

as well as Seed Treatments. Environmental Fate and Effects Division. Office of Pesticide 

Programs. United States Environmental Protection Agency (D375778+).

USEPA. 2014. Guidance on Development and Use of Community Water System Drinking Water 

IntakePercent Cropped Area Adjustment Factors for Use in Drinking Water Exposure 

Assessments:2014 Update. Environmental Fate and Effects Division, Office of Chemical 

Safety and Pollution Prevention, United States Environmental Protection Agency.

Zhao, X., Hickey, R. F., & Voice, T. C. 1999. Long-term evaluation of adsorption capacity in a 

biological activated carbon fluidized bed reactor system. Water Research, 33(13).
11

Appendix A: Model Outputs

Model: SWCC

Variable Volume Water Model, SWCC Compatible Version

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

Performed on: 9/ 9/2014 at 9:33

Peak 1-in-10 = 8.25 ppb

Chronic 1-in-10 = 6.45 ppb

Simulation Avg = 5.08 ppb

YEAR Peak 4-day 21-day 60-day 90-day Yearly Avg Benthic Pk Benthic 21-day

 1 1.26E+00 1.20E+00 9.95E-01 7.73E-01 7.09E-01 2.81E-01 5.22E-01 5.22E-01

 2 1.97E+00 1.90E+00 1.68E+00 1.45E+00 1.36E+00 8.75E-01 1.15E+00 1.15E+00

 3 3.32E+00 3.22E+00 2.91E+00 2.69E+00 2.57E+00 1.75E+00 2.28E+00 2.28E+00

 4 6.15E+00 5.97E+00 5.40E+00 4.81E+00 4.57E+00 3.08E+00 4.09E+00 4.08E+00

 5 5.13E+00 5.05E+00 4.78E+00 4.53E+00 4.48E+00 4.00E+00 4.30E+00 4.30E+00

 6 5.11E+00 5.04E+00 4.83E+00 4.66E+00 4.56E+00 4.08E+00 4.40E+00 4.40E+00

 7 5.33E+00 5.26E+00 5.03E+00 4.78E+00 4.67E+00 4.31E+00 4.56E+00 4.56E+00

 8 6.38E+00 6.27E+00 5.91E+00 5.45E+00 5.26E+00 4.52E+00 5.02E+00 5.02E+00

 9 5.55E+00 5.47E+00 5.24E+00 4.98E+00 4.86E+00 4.56E+00 4.84E+00 4.87E+00

10 7.04E+00 6.96E+00 6.60E+00 6.11E+00 5.90E+00 5.06E+00 5.61E+00 5.61E+00

11 1.07E+01 1.04E+01 9.48E+00 8.66E+00 8.29E+00 6.06E+00 7.51E+00 7.51E+00

12 7.50E+00 7.43E+00 7.21E+00 7.39E+00 7.64E+00 6.63E+00 7.39E+00 7.43E+00

13 7.24E+00 7.16E+00 6.88E+00 6.63E+00 6.55E+00 6.02E+00 6.40E+00 6.39E+00

14 6.67E+00 6.60E+00 6.36E+00 6.13E+00 6.18E+00 5.72E+00 6.17E+00 6.21E+00

15 7.18E+00 7.12E+00 6.90E+00 6.75E+00 6.63E+00 5.96E+00 6.53E+00 6.53E+00

16 6.82E+00 6.75E+00 6.51E+00 6.40E+00 6.54E+00 5.90E+00 6.42E+00 6.46E+00

17 7.11E+00 7.02E+00 6.74E+00 6.42E+00 6.27E+00 5.74E+00 6.19E+00 6.18E+00

18 7.15E+00 7.08E+00 6.86E+00 6.56E+00 6.55E+00 6.05E+00 6.44E+00 6.43E+00

19 7.29E+00 7.21E+00 6.94E+00 6.65E+00 6.51E+00 6.10E+00 6.43E+00 6.43E+00

20 7.98E+00 7.84E+00 7.42E+00 7.12E+00 7.02E+00 6.08E+00 6.70E+00 6.69E+00

21 7.14E+00 7.05E+00 6.77E+00 6.53E+00 6.63E+00 6.01E+00 6.56E+00 6.60E+00

22 7.72E+00 7.65E+00 7.39E+00 7.04E+00 6.84E+00 5.92E+00 6.57E+00 6.57E+00

23 7.53E+00 7.44E+00 7.22E+00 6.91E+00 6.79E+00 6.19E+00 6.60E+00 6.59E+00

24 7.16E+00 7.09E+00 6.85E+00 6.58E+00 6.52E+00 6.21E+00 6.43E+00 6.47E+00

25 7.37E+00 7.27E+00 6.97E+00 6.67E+00 6.57E+00 6.03E+00 6.37E+00 6.37E+00

26 6.72E+00 6.64E+00 6.40E+00 6.13E+00 6.20E+00 5.78E+00 6.18E+00 6.22E+00

27 1.24E+01 1.20E+01 1.08E+01 9.38E+00 8.85E+00 6.43E+00 7.85E+00 7.84E+00

28 7.74E+00 7.66E+00 7.42E+00 7.48E+00 7.62E+00 6.82E+00 7.59E+00 7.63E+00

*******************************************************************************
12

Model SCIGROW

 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:Metconazole

time is 9/22/2014 15:14:15

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

 Application Number of Total Use Koc Soil Aerobic

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

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

 0.125 2.0 0.250 1.21E+03 261.7

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

groundwater screening cond (ppb) = 3.17E-02 

************************************************************************ 
13

MODEL PRZM-GW

Groundwater Analysis for Metconazole and the Wisconsin Corn - WI Central Sands 

Scenario

Estimated groundwater concentrations and breakthrough times for metconazole are presented in 

Table 1 for the Wisconsin Corn - WI Central Sands groundwater scenario. A graphical 

presentation of the daily concentrations in the aquifer is presented in Figure 1. These values were 

generated with the PRZM-GW (Version 1.07). Critical input values for the model are 

summarized in Tables 2 and 3.

Table 1. Groundwater Results for Metconazole and the Wisconsin Corn - WI Central 

Sands Scenario.

Peak Concentration (ppb) 51.8

Post-Breakthrough Mean 

Concentration (ppb)

 46

Entire Simulation Mean 

Concentration (ppb)

 20

Average Breakthrough 

Time (days)

23037.51

Throughputs 1.569701

Table 2. Chemical Properties for Groundwater Modeling of Metconazole.

Koc (ml/g) 1544

Surface Soil Half Life (days) 470.7

Hydrolysis Half Life (days) 0

Diffusion Coefficint Air (cm2/day) 0.0

Henry's Constant 0.0

Enthalpy (kcal/mol) 0.0

Table 3. Pesticide Application Scheme Used for Metconazole (applied every year of the 

simulation)

Application Days 

Relative to 

Emergence Date 

(05/01)

Application Method Application Rate

(kg/ha)

30 Ground application with mass 

distribution increasing 

proportionally with depth to 4 cm

0.134
14

44 Ground application with mass 

distribution increasing 

proportionally with depth to 4 cm

0.134

58 Ground application with mass 

distribution increasing 

proportionally with depth to 4 cm

0.134

72 Ground application with mass 

distribution increasing 

proportionally with depth to 4 cm

0.134

86 Ground application with mass 

distribution increasing 

proportionally with depth to 4 cm

0.134

Figure 1. Aquifer Breakthrough Curve for Metconazole and the Wisconsin Corn - WI 

Central Sands Scenario