### 1 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460



### PC Code: 1 2 894 0 Barcode: D 4 22918 March 4 , 2015

MEMORANDUM

Subject: Drinking Water Assessment for Proposed New Uses (R1 7 0 , PP# 4 F8 29 4 )

for Flutriafol for the establishment of tolerances for residue on Hops (E

Submission 6115).

TO: Tamue Gibson , Risk Manager Reviewer

Hope Johnson, RM 21 Fungicide Branch Registration Division (7505P)

Charles (Billy) Smith, Branch Chief RAB1 Health Effects Division (7509P)

THROUGH: Dana Spatz, Branch Chief

Environmental Risk Branch 3 Environmental Fate and Effects Division

FROM: James K. Wolf, Ph.D., Environmental Scientist

Environmental Risk Branch 3 Environmental Fate and Effects Division (7507P)

REVIEWED BY: James A. Hetrick, Ph.D., Senior Science Advisor

Rosanna Louie

- Juzwiak, RAPL Environmental Risk Branch 3 Environmental Fate and Effects Division

This memo presents recommended drinking water exposure concentrations for the proposed

new use on or in hops for the Cheminova Flutriafol Technical ( 80.0 % a.i.; EPA Reg. No. 4787

- 55)

,

### 2

Cheminova Flutriafol Technical 98.3% (EPA Reg. No. 4787

- 61 ), and TopGuard ® 

### Fungicide ( 11.8 % a.i.; EPA Reg. No. 67760

- 75) Supplemental Labeling )

.

The estimated drinking water concentrations ( EDWCs ) for flutriafol for use in the human health risk assessment are summariz ed in Table 1 . T he EDWCs for flutriafol in groundwater as a source for drinking water are not expected to exceed 1 9 3 μg/L for peak and the 1 65 μg/L for long

- term average concentrations

. For the proposed new uses, the EDWCs for flutriafol in surface water source drinking water are not expected to exceed 15.9 and 5.39 μg/L for peak and chronic exposure, respectively, and 3.53 μg/L for cancer. EFED recommends that the Health Effects Division use 193 μg/L for the peak concentration and the 16 5 μg/L for long

- term average concentration in the human health assessment.

This drinking water exposure assessment is a screening

- level assessment using the PRZM

- GW (version 1.07) (groundwater) and the SWCC (v ersion 1.106) (surface water) models 1 

### and is based upon the maximum number of application s, maximum application rates
, and minimum reapplication interval s ( Table 2 )

. The estimated flutriafol concentrations in groundwater are recommended for the H ealth E ffects D ivision’s (HED) human health risk as sessment as the current EFED policy is to recommend the highest estimated drinking water concentrations ( EDWCs ). It should be noted that the estimates for both surface water and groundwater differ somewhat from the previous assessment even though the application rates and environmental fate data used for model inputs are same

, the models are not. The SWCC (Surface Water Concentration Calculator) has replace d PRZM/EXAMS (and FIRST) and a more recent version of PRZM

- GW ( with updated standard groundwater scenarios) was used for this assessment (1.07 versus 1.01). Because the maximum use rate s (per application and per year basis) is the same for the other uses, this assessment would update the EDWCs for flutriaf ol for all uses.

Uncertainty exists in these EDWCs as the estimates may not consider all dissipation/degradation pathways , especially for groundwater, and it is also unlikely that flutriafol, a fungicide, would be used continually f or a 30 year or longer period. It also should be noted that while these screening

- level EDWCs are representative of potential upper bound exposures, these predictions are based on exposure scenarios that are based on known vulnerable sites

– shallow, unconfined aquifers under an agricultural field with leaching

- prone soils, and adequate precipitation and/or irrigation. Furthermore, it is unlikely that people will be exposed to flutriafol concentrations at these levels based on the available fate data, as well as the predicted bre akthrough time of over 10 years

. The surface water scenarios were selected for the proposed hops use and may not represent the most vulnerable surface water associated with other use sites . However, the estimates for surface water are less than those predicted for groundwater.

1 http://www.epa.gov/oppefed1/models/water/models4.htm and http://www.epa.gov/oppefed1/models/water/

### 3

Table 1 . Maximum Tier I Surface Water and Groundwater EDWCs in μg/L resulting from the proposed use of flutriafol on hops with 30

- year simulations [4 applications @ 0.114 lb a.i./A/year]. Drinking water source (model) 1

- in

- 10 year 30

- year simulation

Acute Chronic Acute Chronic/Cancer Surface water (SWCC) a,b 1 5

. 9 5.39

- 3.5 3 Ground water (PRZM

- GW , v1.07 ) c

- - 193 165

a Michigan Bean Standard Scenario (included with the SWCC)

. b Note: no PCA is applied to these concentrations.

c North Carolina Eastern Coastal Plain Scenario.


### Previously, HED determined that the 1,2,4

- triazole (and the triazole conjugates) degradates should be considered residues of concern in the human health risk assessment. 1,2,4

- Triazole and triazole conjugates triazole analine and triazole acetic acid, are common degradates of conazole pesticides, and are addressed in a separate document 2 

### which was prepared by EFED to address the inclusions of 1,2,4

- Triazole and triazole conjugates in Tier 2 drinking water
assessments.

Proposed New Use

TopGuard ® 

### fungicide is formulated as a soluble concentrate containing 11.8 % of the active ingredient (a.i.) flutriafol (1.04 lb a.i./gallon of product) and is proposed for use on or in hops

. The proposed methods of application are broadcast foliar by ground and ai r spray methods. Flutriafol may not be applied by chemigation. The maximum rate proposed for hops is
compar able to application rate s , number of applications, and season al maximum rate previously assessed ( Table 2 )

.

Table 2 . Flutriafol a Applica tion Rates for Proposed New Use and some Previously Assessed Rates

.

Crop or Crop Group Maximum Single Application Rate (lb a.i./A) Number of

Applications (Minimum Reapplication Interval) Maximum Seasonal

Use Rate (lb a.i./A)

Maximum Proposed Hops Use Rates

H ops a 0.114 4 (14) 0.455 Maximum Rates Previously A s sessed
Cucurbits

, Peppers and other Fruiting vegetables

, Pecan and other Tree Nuts
, Stone fruit 0.114 4 (7) 0.455

a EPA Reg. No. 67760

- 75 TOPGUARD ® (11.8% a.i.) Density = 1.04 lb a.i./gallon * 1 gallon/128 fl oz = 0.008125 lb a.i./ fl oz ; 0.455 lb a.i./A/year (56 fl oz product/A/year)

.

2 1,2,4

- Triazole, Triazole Alanine, Triazole Acetic Acid: Drinking Water Assessment in Support of Reregistration and Registration Actions for Triazole

- derived Fungicide Compounds. 02/28/06. PC 600074, 600011, 600082 D320682

.

### 4

Environmental Fate and Transport Characterization

Flutriafol is persistent in soil (t 1⁄2 

### >1 year) and moderately mobile (K oc 

### <500 mL/g oc 

### ) in the environment . F lutriafol is expected to dissipate slowly with a half

- life of years [never achieved in terrestrial field studies] in the terrestrial environment and therefore repeated applications may lead to accumulation of f lutriafol residues in soil. Flutriafol is expe cted to reach surface water through drift and runoff , and groundwater via leaching . Detailed information on the environmental fate of flutriafol can be found in prior assessme nts (D360863, D356830, D340508, D396757). The environmental fate data are summarized in Table 3

.

Table 3 . Summary of physical/chemical and environmental fate and transport properties of flutriafol.

Parameter Value(s) (units) Source (MRID) Comment

Chemical Name Flutriafol
CAS Name:

α

- (2

- fluorophenyl)

- α

- (4

- fluorophenyl)

- 1H

- 1,2,4

- triazole

- 1

- ethanol

IUPAC Name: (RS

- 1

- (2

- fluorophenyl)

- α

- (4

- fluorophenyl)

- 1H

- 1,2,4

- triazole

- 1

- ethanol 47129901 -

Chemical Structure

-

Molecular Formula C 16 H 13 F 2 N 3 O 47129901

- Molecular Weight 301.3 amu 47129901

- Solubility (20 ° C) 130 mg/L 47129901

- Vapor Pressure (20 ° C) 4 x 10

- 7 Pa 3.00025x10

- 9 torr 47129901

- Henry’s Law constant 9.16 x10

- 12 atm m 3 /mol

- Calculated pK a (20 ° C) 2.3 47129901

- Octanol

- Water Partition Coefficient (log K OW @ pH 7) 2.29 47129901

-

Hydrolysis Half

- life (t 1⁄2 ) pH 5 and 7 Stable 47090416 Stable at all pHs.

Aqueous Photolysis Half

- life (t 1⁄2 ) Stable 47090417 47287601 Florida sunlight

Conditions latitude not specified

- Soil Photolysis Half

- life (t 1⁄2 ) Stable 47090420 47418401 D353179 D350986

[@ 37.5°N]

### 5 Parameter Value(s) (units) Source (MRID) Comment
Aerobic Soil Metabolism Half

- life (t 1⁄2 ) 697 weeks 120, 161, 257, 84, 98, and 315 weeks 347, 239, and 3,466 weeks 47090421 47090422 47090423 Note: values in

weeks . [see D416293, D416294] Anaerobic Aquatic Metabolism (t 1⁄2 ) Stable 47090424 (Total system)
Aerobic Aquatic Metabolism t 1/2 = 42.6 and 36.3 days 47090419 (Total system)
Organic Carbon Partition Coefficient (K OC ) 498, 205, 379, 230, 340, 428, 140 mL/g OC 47090425 47090426 47090427 -

Soil Partition Coefficient (K d ) 3.7, 13.6, 10.6, 6.5, 2.0 mL/g 47090425 47090426 47090427 -

Terrestrial Field Dissipation Half

- life (t 1⁄2 ) t 1/2 = 1155 days 3466 days 2310 days 1155, 866, 770, 866, 1155, 1386 days 47115502 47090431 - Loamy sand.

- Clay loam.

- Sandy clay loam.

- Study conducted at 6 sites in Germany, soil texture classes were not reported.



### No major degradation products ( i.e. , > 10% of applied radioactivity) were identified in any water or soil studies. The degradat ion products formed in the laboratory studies are discussed in detail in prior assessments (D412882). Two minor transformation products 3 

### were identified in the photolysis on soil study [ 1H

- 1,2,4

- Triazole and 2,4’

- Difluorobenzophenone] and three minor [1H

1,2, 4

- Triazole; Triazole

- 1

- acetic acid; 1,2,4

- Triazole

- 1

- alanine] degradation products were identified in the anaerobic aquatic metabolism study

.
Modeling

Th e Tier 1 drinking water estimates for the proposed hops were modeled using the PRZM

- GW mod el (version 1.07) estimates for groundwater (USEPA, 201 4 ) . For surface water, the SWCC (version 1.106) was used to confirm that the surface water estimates remain ed less than the ground water EDWCs

. The six standard PRZM

- GW scenarios 4 

### used in the groundwater simulations were developed to be representative of known vulnerable sites

— shallow, unconfined aquifers under an agricultural field with leaching prone soil and adequate precipitation and/or irrigation . O utput values represent pesti cide concentrations that may be observed in private drinking water wells resulting from the use of groundwater vulnerable to pesticide c ontamination. The results are expected to represent the upper bound values on the concentrations of flutriafol that migh t be found in drinking water supplied by vulnerable groundwater sources

. The 90 th 

### per centile upper bound on the mean aerobic soil metabolism

3 Note the previous drinking water assessment (D360863) incorrectly included the 1,2,4

- Triazole

- 1

- acetic acid degradate. This error would not change the estimated drinking water concentrations (EDWCs).

4 Florida Central Ridge, Florida Potato, Wisconsin Cen tral Sands, Georgia Southern Coastal Plain, North Carolina Easter n Coastal Plain, and Delmarva Peninsula.

### 6

half

- life was re

- evaluated and the average K oc 

### for modeling were used for modeling inputs (USEPA. 2014; D416293, D416204 5 

### ). The selection and procedures for selecting model input parameters followed EFED guidance 6



### . Modeling Inputs

The basic input requirements for PRZM

- GW and the SWCC models are sum marized in Table 4

.

Table 4 . PRZM

- GW and SWCC input parameter values for flutriafol.
Parameter (units) Value Source (MRID) Comment

Both PRZM

- GW and the SWCC Models

Organic Carbon Partition Coefficient (K oc ; mL/g oc ) 322 47090425
47090426
47090427 Represents the mean value of seven values

ranging from 140 to 498 mL/g oc for the parent compound.

Aerobic Soil Metabolism Half

- life @ 25°C (t 1⁄2 ) (days) 7,202 47090421
47090422
47090423 Represents 90% Upper bound confidence

interval for 10 values for the aerobic soil metabolism of the parent compound. [see D 416293, D416294 ] Hydrolysis Stable 47090416 Stable at pH 5, 7, 9
First App ; Days After Emergence (DAE) 1 0

- 10, 24, 38, 52 days after emergence (defined by scenario)

SWCC Model only

Aerobic Aquatic Metabolism Half

- life @ 25°C (t 1⁄2 ) (days) 49.2 47090419 Represents the 90 th percentile of the upper confidence bound on the mean of two half

life values (39.5). Anaerobic Aquatic Metabolism Half

- life @ 25°C (t 1⁄2 ) (days) 0

- No Data

Anaerobic Soil Metabolism Half

- life @ 25°C (t 1⁄2 ) (days) 0 47090424 >365 days in Total system (water/sediment)

Benthic Metabolism Half

- life @ 25°C (t 1⁄2 ) (days) 0

- No Data

Aqueous Photolysis Half

- life @ 25°C (t 1⁄2 ) (days) 0 47109017
47287601 Stable

Soil photolysis 0 47418401 Stable

Foliar Half

- life @ 25°C 0

- No Data Molecular Weight (g) 301.3 47129901

- Vapor Pressure @ 25°C (torr) 3.0x 10

- 9 47129901

- Solubility (mg/L) @ 20°C 130 47129901

-

5 USEPA, 2014. Drinking water assessment for proposed new uses (R190, PP# 3F8199) of Flutriafol on leafy vegetables (Group 4), brassica (cole) leafy vegetables (Group 5), grain sorghum, and cotton and (R190, PP# 3F8174) for cucurbit vegetables, fruiting vegetables, strawberries, tree nuts, and wheat uses. (D416293, D416294; 04/03/14).

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

### 7

Parameter (units) Value Source (MRID) Comment

Spray Drift Fraction (aerial spray) 0.135 EFED Guidance Application Efficiency (aerial spray) 0.95 EFED Guidance
Michigan Application ( first ) Days After Emergence (DAE) 10 10, 24, 38 and 52 Days after emergences
Oregon Application ( first ) Days After Emergence (DAE) 50 50, 64, 7 8, 9 2



### Surface Water Concentrations

The EDWCs for flutriafol (parent) for surface water using the SWCC model for the maximum hops

use rates are provided in Table 5 . Two sites (Oregon Hops and MI Bean) were considered for surface water to confirm that groundwater estimates remained higher then surface water . The Michigan bean exposure scenario was also modeled as a surrogate for use in Wisconsin because of Oregon’s l ower precipitation and that hops are also grown in Wisconsin 7



### . The previous estimate using the FIRST model are also included in Table 5

. The highest peak 1

- in

- 10 year (15.9 μg/L) and annual average flutriafol concentration (5.4 μg/L) and 30 year average (3.5 μg/L) were estimated using the SWCC

. Representative input / output file is given in Appendix 1

.

Table 5

. Surface Water EDWCs in μg/L resulting from the proposed flutriafol use rate on hops [4 applications @ 0.114 lb a.i./A/year] using the SWCC (this assessment) and FIRST (previous assessments )

. Surface Water Concentrations 1

- in

- 10 year 30

- year simulation

Acute Chronic Acute Chronic/Cancer Oregon Hops Scenario ( SWCC) a 4.65 1.81

- 1.37 Michigan Bean (SWCC) a 15.9 5.39

- 3.53

Previous Drinking Water Assessment (D416293, D416293) Surface water (FIRST) b 29.48 2.92

-

a Note: No PCA has been applied to these concentrations.

b PCA of 0.91 was used.



### Groundwater Concentrations

The highest daily groundwater EDWCs estimated by PRZM

- GW (version 1.07) ranged from 51 to 1 9 3 μg/L and the simulation averages ranged from 44 to 1 65 μg/L ( Table 6 ) depending upon the scenario . The Wisconsin Central Sands and North Carolina Eastern Coastal Plains had the highest EDWCs. Representative PRZM

- GW input / output files are given in Appendix 1

. Due to the persistence and mobility of flutriafol, the date of the initial application made little difference in the estima ted groundwater concentrations with PRZM

- GW.

The PRZM

- GW (version 1.01) estimates are also listed in Table 7 for comparison. With the exception of the NC Eastern Coastal Plain scenario, the results with version 1.07 ( Table 6 ) are

7 http://labs.russell.wisc.edu/vegento/files/2012/08/2012

- Hop

- Growers

- Meeting_Groves.pdf

### 8

similar to those obtained with version 1.01 ( Table 7 ). The difference appears to be related to changes in the soil water holding property values which were updated in standard groundwater scenario s

.

Table 6 . PRZM

- GW (version 1.07) estimated flutriafol groundwater concent rations (EDWCs) for the six standard scenarios. 4 applications @ 0.114 lb a.i./A; 14

- day reapplication interval

Highest daily Concentration Post

- Breakthrough Average Average Breakthrough Time

Scenario μg/L Days Delmarva Peninsula 120 11 1 4865 FL Central Ridge Citrus 132 117 3956 FL Potato 69. 8 60 7611 GA Southern Coastal Plain 50.7 44. 4 6552 NC Eastern Coastal Plain 193 165 4932 WI Central Sands 142 12 9 6683



### Table 7 . PRZM

- GW (version 1.0 1 ) estimated flutriafol groundwater concentrations (EDWCs) for the six standard scenarios (USEPA, 2014; D416293, D416294)

. 4 applications @ 0.114 lb a.i./A; 7

- day reapplication interval Highest daily Concentration Post

- Breakthrough Average Average Breakthrough Time

Scenario μg/L Days Delmarva Peninsula 100 86.4 2872 Florida Central Ridge 103 89.2 2865 Florida

– P otato 30 yr 60.3 53.2 7031 GA

- Southern Coastal Plain 49.2 43.2 6245 NC Eastern Coastal Plain 123 104 3664 WI Central Sands 124 115 4018

Cotton 1 application @ 0.26 lb a.i./A and 2 @ 0.114 lb a.i./A (7

- day interval) Delmarva 107.7 92.8 2872 Florida Central Ridge 110.3 95.0 2864 Florida

– P otato 64.6 57.0 7035 GA

- Southern Coastal Plain 52.6 46.6 6245 NC Eastern Coastal Plain 132.2 110.4 3664 WI Central Sands 133.5 124.4 4018

### 9

A ppendix 1. Representative Output from the SWCC and PRZM

- GW Models.

Surface Water (Surface Water Concentration Calculator, version 1.07)

Summary of Water Modeling of flutriafol and the USEPA Standard Reservoir

Estimated Environmental Concentrations for flutriafol are presented in Table 1 for the USEPA standard reservoir with the MIbeansSTD field scenario. A graphical presentation of the year

- to

- year peaks is presented in Figure 1. These values were ge nerated with the Surface Water Concentration Calculator (SWCC Version 1.106). Critical input values for the model are summarized in Tables 2 and 3.

This model estimates that about 2.4% of flutriafol applied to the field eventually reaches the water body. The main mechanism of transport from the field to the water body is by runoff (81.2% of the total transport), followed by spray drift (17.1%) and e rosion (1.7%).

In the water body, pesticide dissipates with an effective water column half

- life of 65.3 days . (This value does not include dissipation by transport to the benthic region; it includes only processes that result in removal of pesticide from the compl ete system.) The main source of dissipation in the water column is metabolism (effective average hal f

- life = 124.6 days) followed by washout (137 days) and volatilization (4.031344E+07 days).

In the benthic region, pesticide is stable. The vast majority of the pesticide in the benthic region ( 97.2%) is sorbed to s ediment rather than in the pore water.

Table 1. Estimated Environmental Concentrations (ppb) for flutriafol. Peak (1

- in

- 10 yr) 15.9

4

- day Avg (1

- in

- 10 yr) 15.4

21

- day Avg (1

- in

- 10 yr) 13.7

60

- day Avg (1

- in

- 10 yr) 11.5

365

- day Avg (1

- in

- 10 yr) 5.39

Entire Simulation Mean 3.53

Table 2. Summary of Model Inputs for flutriafol.

Scenario MIbeansSTD Cropped Area Fraction 1.0
Koc (ml/g) 322

Water Half

- Life (days) @ 25 °C 49.2

Benthic Half

- Life (days) @ 25 °C 0 Photolysis Half

- Life (days) @ 40 °Lat 0 Hydrolysis Half

- Life (days) 0

Soil Half

- Life (days) @ 25 °C 7202

Foliar Half

- Life (days) 0

Molecular Wt 301.3
Vapor Pressure (torr) 3.0e

- 9 Solubility (mg/l) 130

### 10

Table 3. Application Schedule for flutriafol. Date (Days Since Emergence) Type Amount (kg/ha) Eff. Drift

10 Foliar 0.128 0.95 0.135

24 Foliar 0.128 0.95 0.135
38 Foliar 0.128 0.95 0.135
52 Foliar 0.128 0.95 0.135

Figure 1. Yearly Peak Concentrations

PRZM

- GW (version 1.07)

Groundwater Analysis for flutriafol and the NC Eastern Coastal Plain

- Norfolk Loamy Sand

- Cotton Scenario

Estimated groundwater concentrations and breakthrough times for flutriafol are presented in Table 1 for the NC Eastern Coastal Plain

- Norfolk loamy sand

- Cotton groundwater scenari o. 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 flutriafol and the NC Eastern Coastal Plain

- Norfolk loamy sand

- Cotton Scenario. Peak Concentration (ppb) 193

Post

- Breakthrough Mean Concentration (ppb) 165

Entire Simulation Mean Concentration (ppb) 94.3

Average Breakthrough Time (days) 4931.997

Throughputs 2.222224

### 11

Table 2. Chemical Properties for Groundwater Modeling of Flutriafol

. Koc (ml/g) 322 Surface Soil Half Life (days) 7202 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 flutriafol . This application scheme was applied every year of the simulation. Application Days Relative to Emergence Date (05/15) Application Method Application Rate (kg/ha)

10 Above canopy application 0.128
24 Above canopy application 0.128
38 Above canopy application 0.128
52 Above canopy application 0.128

Figure 1. Aquifer Breakthrough Curve for flutriafol and the NC Eastern Coastal Plain

- Norfolk Loamy Sand

- Cotton Scenario