1

**MEMORANDUM DATE:**  September 30 , 201 4 **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 Chi ef Risk Integration Minor Use, and Emergency Response Branch Registration Division (7505P) Erin Malone, Risk Manager Reviewer Hope Johnson, Product Manager Team 21 Cy nthia Giles
- Parker, Branch Chief Fungicide Branch Registration Division (750 5P) **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 (EDWC s ) of metconazole ( 5
- [( 4
- Chlorophenyl) methyl]
- 2,2
- dimethyl
- 1
- (1 H
- 1,2,4
- triazol
- 1
-

ylmethyl)cyclopentanol

] ) in surface water and groundwater in support of the proposed Section 3 new u se s . The Interregional Research Project Number 4 (IR
- 4) submitted a tolerance petition for metconazole new uses o n pea/bean (dried shelled) and sunflower. Foliar spray applications ( aerial and ground boom) are OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION **UNITED STA TES ENVIRONMENTA**  **L PROTECTION A GENCY**  WA SHINGTON, D.C. 20460

**PC Code** : 125619 **DP Barcode:** D4186742

being proposed for the new uses . The IR - 4 also revised exi s ting crop groupings b y 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 r apeseed S ubgroup 20A
. Since there are no changes in application rates and methods for the revised crop group ing s , p revious drinking water assessments ( DWA s) 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 Effect s 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 o f 45.5 μg/L (peak) and 22.8 μg/L (30 ye ar 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. Recentl y, EFED implemented a revised guidance for P CA (USEPA 2014 ). Since metconazole can be used in agricultural and non agricultural settings , a PCA factor of 1.0 was used to revise the previousl y 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 remain s unchanged for turf. This is the first time the PRZM - GW model ha s 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 applicatio n rates for proposed use s are lower than turf, no additional modeling for PRZM - GW modeling is warranted at this time. The e stimated P RZM - 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 , D 340378 ). Therefore, the current EDWCs supersede the previousl y 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 U**  **ses of Metconazole**  **for Drinking W**  **ater Sources**  **Drinking Water Source**  **Crop Scenario (** **Model )**  **Peak Exposure**  **( A**  **cute) (μg/L)**  **Annual Mean**

**Exposure (** **N on**  **- C**  **ancer Chronic)**  **(μg/L) 30**  **- year Mean** 

**Exposure (Cancer**  **Chronic) (μg/L)**  Surface Water Turf 45.5 31.3 **22.8 1** 

Cranberry **49.6 1**  **43.9 ,**  **1, 2**  NA 3 Groundwater WI Central Sand Scenario **51.8 ,1,**  **4** NA 3 **20.0 ,1,**  **4** 1 Bolded values are the recommended EDWCs for surface water and groundwater for metconazole uses3

**Table 1**  **. Recommended**  **EDWCs for the Proposed U**  **ses of Metconazole**  **for Drinking W**  **ater Sources**  **Drinking Water Source**  **Crop Scenario (** **Model )**  **Peak Exposure**  **( A**  **cute) (μg/L)**  **Annual Mean**

**Exposure (** **N on**  **- C**  **ancer Chronic)**  **(μg/L) 30**  **- year Mean** 

**Exposure (Cancer**  **Chronic) (μg/L)**  2 T he provisional cranberry scenario is applicable for a year simulation only
. 3 Not applicable 4 PRZM - GW model was used to reasses s groundwater EDWCs for turf use, which has the highest the highest application rate o f 0.6 lbs a.i/A for metconazole ; groundwater EDWCs are based on a PRZM - GW 100 years simulation **Proposed U se**  Metconazole is a broad
- spectrum s ys temic 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 tolerance s for revised crop groups **(Table 2)**
. According to the proposed label (Metconazole 50WDG Fungicide), metconazole can be applied at a maximum application rate/ye ar of 0. 1 25
- 0.44 lb a.i./A via ground and aerial application method s. Two of the proposed uses have not been considered previously in drinking water assessments. These include use s on pea

/ bean ( dried shelled) and sunflower
. Since there are no changes in application rates and methods for the revised crop groupings, previous DWA s 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 App lication 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 App lication Type EPA Reg # Comments/restrictions
Stone Fruit (Group 12
- 12) 0.11
- 0.125 3 0.375 7 - 14 14 Aerial 59639
- 147 Maximum two sequential applications
Tree Nut (Group 14
- 12 0.078
- 0.11 4 0.44 7 - 14 25 Aerial 59639
- 147 Maximum two sequential applications **Residues of Concern** Three degradates were observed at greater than 10% of the applied dose in laboratory fate studies: M30, hydrox ym etconazole, and M13. However, the Residues of Concern Knowledgebase Subc ommittee (ROCKS) reported that the residue of concern for metconazole in drinking water is the parent only (USEPA 2008 , D 348234 ). Degradates were excluded in the DWA. A d etailed rationale for excluding several metconazole metabolites is included in the previous DWA (USEPA 2010 , D 3 75778+ ). **Modeling Approach and Input Parameters**  **Models Surface Water**  The Surface Water Concentration Calculator (SWCC v 1.106) model 1 was used to generate E DW Cs 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 fo r multiple (usually 30) years and the E DW Cs represent peak values that are expected once every ten ye ars 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 non
agricultural settings (USEPA 2012). **Ground w** **ater** The Screening Concentration in Ground Water (SCI
- GROW v2.3, Jul. 29, 2003) model 1 is 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 L eaching P otential (RILP) as the

1 http://www.epa.gov/oppefed1/models/water /index.htm5

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
- pa ge (http://www.epa.gov/oppefed1/models/water/#scigrow). PCAs are not applicable for the SCI
GROW 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 w as also estimated using the PRZM
GW model (USEPA, 2012 c ), 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. P RZM - 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 suppl y that is located directl y beneath a rural agricultural field foll owing many ye ars of pesticide application. Since there is n o breakthrough (i.e., the number of days that it takes for the applied chemical to reach the aquifer) observed for 30 ye ars 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 m odel s are in **Table 3, Table 4, and Table 5** , respectivel y . 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 )
. S ample model output files are located in **Appendix B. Table**  **3 .**  **SWCC Input Parameters for Metconazole Proposed Uses**  **Param eter**  **Input Value and Unit Source**  **Comment Scenarios for proposed Uses**  Pea and Bean (Crop subgroup 6C) Sunflower (Crop subgroup 20B) MIbeanSTD NDCanolaSTD 1 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 (d ays ) 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 Hydroly sis (t 1/2 ) 0 MRID 46902201 S table6

**Table 3**  **. SWCC**  **Input Parameters for Metconazole Proposed Uses Param**  **eter Input Value and Unit**  **Source Comment**  A pplication efficiency and Spray Drift (fraction) Aerial: 0.95 and 0.135 Ground: 0.99 and 0. 066 Input Guidance 3 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 Cis
isomer4 Hydroly sis (t 1/2 ) 0 MRID 46902201 S table Aquatic photolysis (t 1/2 ) 72 days MRID 46902202
--- Aerobic soil metabolism (t 1/2 ) 470.7 days MRID 46970901 MRID 46902204 MRID 46808408 Upper 90 th %
- ile

confidence bound on the mean of six DT 50s Aerobic aquatic metabolism (t 1/2 ) Stable MRID 46902205 Pond water - sediment system from Germany Anaerobic aquatic metabolism (t 1/2 ) 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**  **Param eter**  **Value Source**  **Comments** Application Rate (lb s 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 fo ur 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 Parameters**  **1 for**  **M etconazloe**  **Uses Variable Nam**  **e 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 label7

**Table 5**  **. PRZM -**  **GW Input Parameters**  **1 for**  **M etconazloe**  **Uses Variable Nam**  **e 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 Hydroly sis, DT 50 (Days) S table MRID 46902201
--- Aerobic Soil Metabolism DT 50 (Days) 470.7 days MRID 46970901 MRID 46902204 MRID 46808408 Upper 90 th %
- ile

confidence bound on the mean of six half
- lives
Koc ( mL/g oc ) 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 e stimated metconazole concentrations in surface water used for drinking water are summarized in **Table 6**
. The e stimated concentrations in surface water for use on sunflower resulted in the highest EDWC s at 8.25 μg/Lfor acute , 6.45 μg/L for annual mean and 5.08 μg/L for a 30
- ye ar 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 e stimated metconazole concentrations in groundwater used for drinking water are summarized in **Table 7**  . The estimated concentrations in groun dwater for use on turf resulted in the highest EDWC s at 51.8 μg/Lfor acute and 20.0 μg/Lfor a 100
- ye ar annual average. The PRZM - GW EDWCs are higher than the SCI
- GROW EDWCs for the proposed uses and previously recommen ded 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**  **A pplications 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 water 1 **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 W ater Concentration Calculator was used to determine EDWCs in surface water 2 Aerial application 3 Ground boom application8

**Table 7**  **. Results from**  **PR ZM**  **- GW**  **and SCI -**  **GROW M**  **odeling B**  **ased on Metconazole**  **U se**  **s on Turf**  **and Proposed New Uses Crop**  **Scenario Highest**  **Daily Value (**  **μ g/L)**  **A verage (**  **μ g/L)**  **Average S**  **im ulation**  **Breakthrough Time (days)**  Turf 1 ( 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 **51.8 2**  **20.0 2**  23037 Pea/Bean (Dried Shelled) and Sunflower ( 0. 125 lbs a.i./A x 2 applications) Generic Scenario 3 0.0 32 0.0 32 NA4

1 PRZM - GW mo deled the highest metconazole application rate of 0.6 lbs a.i/A for metconazole use s 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) P rogram Data Warehouse (http://infotrek.er.usgs.gov/nawqa_queries/jsp/swmaster.jsp ) , searched o n September 08 , 2014
. Metconazole was not detected in 75 s urface water sample s collected from multiple states (CA, GA, IA, IN, M O , 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 accuratel y represent spatially and temporall y 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
. Metconaz o le is sta ble to hydrol ys is. Therefore, metconazole will not degrade by

hydroly sis during the time that elapses from drinking water intake through distribution to the first tap. Metconazole is also not sensitive to aqueous photoly sis. Therefore, if ultraviolet light were used as a means of disinfection, degradation of metc onaz ole would not be expected to be significant
. Metconazole has a lo w degradation rate in aerobic aquatic environments, therefore, there is not expected to be significant degradation during water treatment . The most successful treatment process for remov ing pesticides from drinking water is thought to be treatment with granular activated carbon (GAC) , which is only used in larger9

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 ( Badri yha 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** Badri yh a, B. N., Ravindran, V., Den, W., & Pirbazari, M. 2003. Bioadsorber efficiency , design, and p erformance 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 D3 40378)
. 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 D3 50276)
. 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 (D 3 75778+)
. USEPA. 2014
. Guidance on Development and Use of Community Water System Drinking Water Intake Percent Cropped Area Adjustment Factors for Use in Drinking Water Exposure Assessments :2014 Update . Environmental Fate and Effects Division, Off ice of Chemical Safety and Pollution Prevention , United States Environmental Protection Agency
. Zhao, X., Hickey , R. F., & Voice, T. C. 1999. L ong - 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+0 0 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+0 0 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 2 4 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 m etconazole are presented in Table 1 for the Wisconsin Corn
- WICentral 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 Hydroly sis Half Life (days) 0 Diffusion Coefficint Air (cm2/day) 0.0 Henry's Constant 0.0 Enthalpy (kcal/mol) 0.0 **Table 3. Pesticide A** **pplication S**  **cheme U**  **sed for Metconazole (**  **applied every year of the simulation**  **)** Application Day s 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 0.13414

44 Ground application with mass

distribution increasing proportionally

with depth to 4 cm 0.134
58 Ground application with mass

distribution increasing proportionally

w ith 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**