Page 1 of 8 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460

PC Code: 270000 DP Barcode: 422934

MEMORANDUM September 22, 2014

SUBJECT: Isofetamid: ADDENDUM to Dri nking Water Exposure Assessment for the Section 3 Registration of the New Chemical Isofetamid, in Support of Proposed Almond, Lettuce, Grapes (Subgroup 13-07F), Low Growing Berries (Subgroup 13-07G), Rapeseed (Subgroup 20A), and Turf Uses.

TO: Christine Olinger, Branch Chief Risk Assessment Branch 3 Health Effects Division (7509P)

Cynthia Giles-Parker, Branch Chief Fungicide Branch Registration Division (7505P)

THROUGH : Dana Spatz, Branch Chief Environmental Risk Branch 3 Environmental Fate and Effects Division (7507P)

FROM: Melanie Biscoe, Physical Scientist Environmental Risk Branch 3 Environmental Fate and Effects Division (7507P)

PEER REVIEW : James Hetrick, Ph.D., Senior Science Advisor Environmental Risk Branch 3 Environmental Fate and Effects Division (7507P)

Executive Summary

The Environmental Fate and Effects Division (EFED) has completed a Drinking Water Assessment (DWA) addendum for the Section 3 registration decision on the new broadspectrum, systemic fungicide isofetamid (IK F-5411) (PC Code 270000). The previous DWA (DP 410179, June 11, 2014) considered the following proposed uses: almond, lettuce, grapesPage 2 of 8 (Subgroup 13-07F), low growing berries (Subgro up 13-07G), rapeseed (Subgroup 20A), and turf uses; however, potential surface- water-sourced drinking water e xposure from isofetamid use on cranberry was not assessed. This DWA addendum fully considers the proposed cranberry use that is included in the proposed low-growi ng berries Subgroup 13-07G, which results in the highest estimated potential concentrations in dr inking water when considering both surface water and groundwater sources.

The maximum EDWCs calculated in this addendum are shown in Table 1. In surface water, the highest estimated 1-in-10 year peak (acu te) concentration of isofetamid is 136 μ g/L, and the highest estimated 1-in-10 year an nual average concentration is 110 μ g/L. EFED recommends using the 1-in-10 year peak surface water EDWC value (136 μ g/L) for assessing human health dietary risk from acute exposures and the maximum 1-in-10 year annual average surface water EDWC value (110 μ g/L ) for assessing human heal th dietary risk from chronic and life-time/cancer exposures. Note that in the previous DWA, the maximum EDWC for acute exposures was 96 μ g/L (surface water using Surface Water Concentration Calculator version 1.101, low-growing berry use) and the maximum EDWC for chronic exposures was 43
μ g/L (groundwater using Pestic ide Root Zone Model-Ground Water version 1.07, turf use).

Table 1. Maximum estimated drinking water co ncentrations (EDWCs) in parts per billion ( μ g/L) resulting from applicatio ns of Isofetamid on Cranberry.

Drinking Water Source (model) Application Information Acute Chronic

μ g/L

Pesticide Flooded Applications Model (PFAM) 5 applications of 0.442 lba.i./acre with a 7 day retreatment interval and a 30- day resistance management interval Peak 1-in-10 Year Chronic 1-in-10 Year

136 110

Use Assessed

Isofetamid use on cranberry is assessed in th is DWA addendum. Use information from the proposed isofetamid labels are in Table 2

. Table 2. Cranberry Application Informat ion from the Proposed Isofetamid Labels 1,2

. Maximum Individual Application Rate lbs a.i./A Number of Applications/ year Minimum Application

Interval

(days) Max Annual Application Rate in lbs a.i./A/year Application Method Comments

0.442 5 3 7 2.28 Ground Aerial Chemigation 4 Do not make more than two sequential applications of isofetamid.Page 3 of 8 1 There is 3.33 lb a.i. (isofetamid) in one gallon of the isofetamid products.

2 This proposed use is part of the low growing berries crop subgroup 13-07G, which includes bearberry, bilberry, blueberry (low bush), cloudberry, cranberry, lingonberry , muntries, partrisgeberry, strawberry, and cultivars, varieties, and/or hybrids of these.

3 This is not specified on the label; it is assumed by dividing the maximum application rate allowed/year by the maximum single application rate.

4 Only center pivot, motorized lateral move, traveling gun, so lid set or portable (wheel move, side roll, end tow, or hand move) irrigation systems.

Drinking Water Modeling

The Pesticide Flooded Applicati on Model (PFAM version 1.0) model was used to generate Estimated Drinking Water Concentrations (EDWCs ). Detailed descriptions, documentation, and links for running the PFAM model may found at http://www.epa.gov/oppefed1/models/water/index.htm

. The PFAM generates daily, 1-in-1 0-year, and 30-year average EDWCs of isofetamid that may occur in and downstream of flooded fields th rough dry-field runoff, overflows, and manual releases of water. PFAM simulates pesticide application, movement and transformation in a watershed and the resultant pes ticide loadings to a receiving water body via runoff, erosion, and spray drift, and then simulates the fate of the pesticide and resulting concentrations in the water body. The standard watershed geometry used for drinking water assessments assumes application to a 427-acre watershe d that drains into an adjacent 13-acre reservoir that is an average of 2.7 mete rs deep (4,665,600 m 3 volume). A Percent Cropped Area (PCA) adjustment factor is not available for cranberries, and a su rrogate PCA was not select ed in this screening assessment for the cranberry use.

In this DWA addendum, weather data files for LaCrosse, Wisc onsin; Atlantic City, NJ; and Boston, MA were used to simulate conditions in areas where cranberry farming is prevalent. Likely application dates were selected based on guidance and references from the Biological and Economic Analysis Division (BEAD) (McMa nus and Colquhoun 2014; Oudemans et al. 2013; Sandler and DeMoranville 2008). Because the propos ed label language prohibits more than two sequential isofetamid applica tions, surface water modeling c onducted in this DWA addendum assumes that a pair of isofetamid applications wi th a 7-day retreatment interval are subsequently separated from the next pair of applications by 30-day interval. Input parameters used in the PFAM are found in Table 3

. Table 3. Isofetamid Cranberry Application Input Parameters Used in the PFAM. Input Parameter Value Comments Source Water column half-life (d) at 20 °C 240.52 Represents the 90th percentile confidence bound on the mean of two test system half-lives. MRID 49011986

Benthic Compartment half-life at 20 °C (d) 100,000 (default) 1 Represents no biodegradation under anaerobic conditions. MRID 49011985

Unflooded half-life at 20 °C (d) 60.92 Represents the 90th percentile confidence bound on the mean of four soil half-lives. MRIDs 49011981 and 49011982Page 4 of 8 Input Parameter Value Comments Source Aqueous photolysis half-life at 40° Latitude (d) 1.8 The longer half-life of the two halflives calculated in the study. MRID 49011977

Hydrolysis half-life (d) 100,000 (default) Represents no hydrolysis. MRID 49011976 Organic Carbon Partition Coefficient (K OC ) (L/kg OC ) 491 The mean of isofetamid K F oc's calculated for five soils. MRID 49011979

Molecular weight (g/mol) 359.48 Product chemistry data (Calculated)
Vapor pressure at 20 °C (torr) 4.4 x 10 -11 Product chemistry data MRID 49011905
Water solubility at 20 °C (mg/L) 5.33 Product chemistry data MRID 49011905

Heat of Henry at 25 °C (J/mol) 54872.4 Equals 8.314 × enthalpy of salvation (6,600 K) estimated by HenryWin v3.20. (Calculated)

Application Date & Rate (kg a.i./ha) 5/17: 0.495 5/24: 0.495 6/23: 0.495 6/30: 0.495 7/30: 0.495 Maximum proposed single application rate and maximum number of applications. Minimum

re-application intervals (7 days) applied, in addition to (assumed) 30 day intervals for mandatory resistance management measures. Proposed label and likely application

timeframes for Wisconsin, New Jersey, and Massachusetts (BEAD) Slow Release (1/day) 0 for each application Estimated (Estimated)
Meteorology data location (metfile code) La Crosse, WI (w14920) Atlantic City, NJ (w14734)

Boston, MA (w14739) Meteorological file for a location near cranberry agriculture. CEAM, 2011

Flood Events Starting on 10/1, 2 events 3 days apart Estimated (Estimated)

Fill level (m) 10/1: 0.305 10/4: 0 Minimum flood depth and release depth. (Estimated)

Wier level (m) 10/1: 0.458 10/4: 0 Estimated wier heights. (Estimated)
Min. Level (m) 0 for each event Estimated minimum water level (Estimated) Turn Over (1/day) 0 for each event Estimated turn over (Estimated) Crop zero height reference May 1 Estimated value (Estimated)
Days from zero to full height 120 Estimated value (Estimated)
Days from zero height to removal 153 Estimated value (Estimated)
Max. aerial coverage 0.2 Value from OR berries PE scenario (Estimated)
Area of application (m 2 ) 526,090 Represents 10x the area of the Index Reservoir (Calculated)

Area of watershed (m 2 ) 1,728,000 Area of the Index Reservoir watershed USEPA, 2010Page 5 of 8 Input Parameter Value Comments Source Watershed curve number 84 Value for fallow conditions in OR berries and other PE scenarios (Estimated)

Base flow (m 3 /sec) 0 Value based on conceptual models for Index Reservoir and Farm Pond (Estimated)

Modeling Results

Table 4 reports the EDWCs calculated for each locat ion representing cranberry use areas. The maximum 1-in-10 year peak EDWCs in surface water range from 91 to 136 μg/L, the 1-in-10 year annual average EDWCs in surface water ra nge from 62 to 110 μg/L. The LaCrosse, Wisconsin location results in the maximum ED WCs. The PFAM output for the surface water EDWCs for the LaCrosse, Wiscons in location is attached in Appendix A

. Table 4. Isofetamid Surface Water EDWCs for the Cranberry Use.

Weather File

Location 1-in-10 Year Peak Concentration (μg/L) 1-in-10 Year Chronic Concentration (μg/L) La Crosse, WI

(w14920) 136 110
Atlantic City, NJ (w14734) 91 62

Boston, MA

(w14739) 103 72

Bibliography

McManus, Patricia; Colquhoun, Jed; Nice, Glenn; and Guedot, Christelle. 2014. “Cranberry Pest Management in Wisconsin.” UW Extension . A3276.

Oudemans, Peter; Majek, Bradley; and Rodr iguez-Saona, Caesar. 2013. 2013 Commercial Cranberry Pest Control Recomme ndations for New Jersey.” Rutgers New Jersey Agricultural Experiment Station: Coopera tive Extension Bulletin E308

. Sandler, Hilary and DeMoranville, Carolyn. 2008. "Cranberry Production: A Guide for Massachusetts - Summary Edition." Cranberry Production Guide. Paper 1. http://scholarworks.umass.edu/cranberry_prod_guide/1

USEPA 2009. Guidance for Selecting Input Parame ters in Modeling the Environmental Fate and Transport of Pesticides. Version 2.1 October 22, 2009. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Divi sion. Arlington, VA. http://www.epa.gov/oppefed1/mode ls/water/input_guidance2_28_02.htmPage 6 of 8 USEPA. 2010. R. Jones, K. Costello, J. Hetric k, J. Lin, R. Parker, N. Thurman, and C. Peck. Development and Use of the Index Reservoir in Drinking Water Exposure Assessments. U.S. Environmental Protection Agency, Office of Pesticide Programs. Apr. 15, 2010. Online at: http://www.epa.gov/oppefed1/models /water/index_reservoir_dwa.html

USEPA 2012. Development and Use of Per cent Cropped Area and Percent Turf Area Adjustment Factors in Drinking Water Expos ure Assessments: 2012 Update. March 16, 2012. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. Arlington, VA. http://www.epa.gov/oppefed1/models /water/pca_adjustment_dwa.html

USEPA 2014. D411110. Isofetamid: Report of the Residues of Concern Knowledgebase Subcommittee (draft). U.S. Environmental Pr otection Agency, Office of Pesticide Programs, Health Effects Division. Arlington, VA.Page 7 of 8 Appendix A. Isofetamid Cranberry Use PFAM Output for LaCrosse, Wisconsin Weather File Location

Variable Volume Water Model, Version 0.0

******************************************* Performed on: 9/ 3/2014 at 15:20 Standard Reservoir, Area = 52555 m2, Depth = 2.73 m Chemical # 1

Peak 1-in-10 = 1.36E+02 ppb Chronic 1-in-10 = 1.10E+02 ppb

4-day avg 1-in-10 = 1.34E+02 ppb 21-day avg 1-in-10 = 1.30E+02 ppb 60-day avg 1-in-10 = 1.24E+02 ppb 90-day avg 1-in-10 = 1.24E+02 ppb

YEAR Peak 4-day 21-da y 60-day 90-day Yearly Avg 1 7.72E+01 7.67E+01 7.55E+01 7.43E+01 7.28E+01 5.63E+01 2 1.20E+02 1.15E+02 1.07E+02 1.04E+02 9.75E+01 8.62E+01 3 1.08E+02 1.06E+02 1.00E+02 9.62E+01 9.45E+01 8.54E+01 4 9.53E+01 9.46E+01 9.33E+01 9.15E+01 8.96E+01 7.90E+01 5 1.39E+02 1.36E+02 1.31E+02 1.21E+02 1.13E+02 9.43E+01 6 1.04E+02 1.01E+02 9.72E+01 9.26E+01 9.11E+01 8.57E+01 7 9.35E+01 9.06E+01 8.15E+01 8.70E+01 8.82E+01 6.70E+01 8 1.13E+02 1.09E+02 1.04E+02 1.02E+02 1.02E+02 9.11E+01 9 1.16E+02 1.12E+02 1.09E+02 1.09E+02 1.07E+02 9.88E+01 10 1.26E+02 1.26E+02 1.25E+02 1.23E+02 1.21E+02 1.09E+02 11 1.36E+02 1.34E+02 1.34E+02 1.32E+02 1.31E+02 1.23E+02 12 1.69E+02 1.64E+02 1.62E+02 1.52E+02 1.43E+02 1.11E+02 13 1.02E+02 9.78E+01 9.58E+01 9.38E+01 9.65E+01 8.35E+01 14 1.25E+02 1.25E+02 1.24E+02 1.24E+02 1.23E+02 1.04E+02 15 1.11E+02 1.09E+02 1.05E+02 1.14E+02 1.17E+02 9.46E+01 16 1.08E+02 1.07E+02 1.06E+02 1.03E+02 1.00E+02 8.69E+01 17 1.27E+02 1.26E+02 1.25E+02 1.24E+02 1.24E+02 1.10E+02 18 1.33E+02 1.26E+02 1.22E+02 1.20E+02 1.21E+02 8.24E+01 19 1.18E+02 1.14E+02 1.08E+02 1.01E+02 9.85E+01 9.00E+01 20 1.13E+02 1.10E+02 1.06E+02 9.50E+01 9.37E+01 7.34E+01 21 8.87E+01 8.50E+01 8.45E+01 8.37E+01 8.36E+01 7.14E+01 22 1.16E+02 1.15E+02 1.12E+02 1.09E+02 1.07E+02 9.97E+01 23 1.30E+02 1.28E+02 1.25E+02 1.21E+02 1.19E+02 9.51E+01 24 9.47E+01 9.43E+01 9.35E+01 9.17E+01 9.00E+01 7.68E+01 25 1.11E+02 1.09E+02 1.05E+02 9.95E+01 9.55E+01 8.34E+01 26 1.21E+02 1.18E+02 1.14E+02 1.12E+02 1.09E+02 8.74E+01 27 9.86E+01 9.64E+01 9.29E+01 8.55E+01 8.33E+01 7.43E+01Page 8 of 8 28 8.15E+01 7.91E+01 7.57E+01 7.29E+01 7.53E+01 6.43E+01 29 9.46E+01 9.37E+01 9.14E+01 8.97E+01 8.81E+01 8.00E+01 30 9.76E+01 9.35E+01 8.54E+01 8.17E+01 8.48E+01 7.49E+01

*********************************************************************** Effective compartment halflives averaged over simulation duration:

washout halflife (days) = 228.8117 water col metab halflife (d ays) = 421.2925 hydrolysis halflife (days) = 100109.8 photolysis halflife (days) = 353.5643 volatile halflife (days) = 1.2372009E+08 total water col halflife (days) = 104.3581

zero burial benthic metab halflife (days) = 175159.0 benthic hydrolysis halflife (days) = 5402744. total benthic halflife (days) = 169658.6 ***********************************************************************

**************** Inputs ******************* Chemical # 1 240.520000000000 Water Column System Halflif e(except photo & hydrolysis = 100000.000000000 Benthic Compartm ent Halflife (excep t hydrolysis) = 1.80000000000000 Photolysis Halflife = 100000.000000000 Hydrolysis Halflife = 359.480000000000 Molecular Wieght = 4.400000000000000E-011 Vapor Pressure = 5.33000000000000 Solubility = 491.000000000000 Koc = 20.0000000000000 Aerobic Reference Temper = 20.0000000000000 Anaerobic Reference Temper = 40.0000000000000 Reference Latitude = 54872.4000000000 Enthalpy of Henry = 25.0000000000000 Henry Reference Temperature ****************** End of Run ************************ ******************************************************