1 OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

February 19 , 2015

PC Code: 050410

MEMORANDUM DP Barcode: 4 24167

SUBJECT: Fluensulfone: Drinking Water Exposure Assessment for Proposed New U ses on

Turfgrass

FROM: J a m es Lin, Environmental Engineer

Environmental Risk Branch II Ecological Fate and Effects Division (7507P)

THROUGH: Greg Orrick, Environmental Scientist

Brian Anderson, Branc h Chief

Environmental Risk Branch II Ecological Fate and Effects Division (7507P)

TO: Michael Doherty, Risk Assessor

Christina Swartz, Branch Chief

Risk Assessment Branch II Health Effects Division (7509P)

Reuben Baris

, Risk Manager Reviewer

Mark Suarez , Team Leader, PM Team 7

Insecticide

- Rodenticide Branch Registration Division (7505P)

1. EXECUTIVE SUMMARY

This assessment provides estimated drinking water concentrations (EDWC) from the use of fluensulfone on turf in support of the Health Effects Division’s (HED) human health risk

assessment. As discussed below, the EDWCs based on turf uses are less than tho se of the previous assessment that was based on cucurbits and fruiting vegetables. Therefore, the EDWCs of 77.7 μg/L, and 52.5 μg/L should be used for acute and chronic drinking water exposure, respectively.

2. USE CHARACTERIZATION

Quali

- Pro® Nimitz® 1.5G Nematicide is a granule formulation containing 1.5% of fluensulfone active ingredient by weight

. The label specifies that applications should be uniformly

broadcast ed over turfgrass area suspected to have nematodes or with a history of nematodes

.2

The use rate range is 60

– 120 pounds product per acre with a maximum seasonal amount of 240 pounds product per year. Depending on nematode populations and damage, applications can be made monthly, bi

- monthly or sequentially. It is recommended to irrigate follo wing application with an adequate amount of water (generally 0.5 inches). The proposed label specifies three application scenarios:

(1) 60 lb/acre (0.9 lb ai/ac) can be applied at 1 month intervals for 4 consecutive months; (2) 80 lb/acre (1.2 lb ai/ac) can be applied at 1 month interval for 3 consecutive months; and (3) 120 lb/ac (1.8 lb ai/ac) can be made in spring or early summer with a second application

at the same rate 2

- 6 months following the initial broadcast.

3. PREVIOUS DRINKING WATER ASSESSMENTS

Two drin king water assessments have been generated for cucurbits and fruiting vegetables uses (DP 411774 and DP 417634). The assessments present maximum EDWCs from ground water sources (based on PRZM

- GW) of 77.7 μg/L, and 52.5 μg/L, for acute and chronic exposure

, respectively. The residues of concern include parent fluensulfone and the degradate methyl

sulfone.

4. DRINKING WATER ASSESSMENT FOR TURF USES

The detailed fate characterizations including product chemistry, transport, mobility, degradation,

field studies, environmental degradates, and selections of residues of concern have been presented in the previous drinking water assessments. Only modeling input information and output results are presented in this assessment.

PRZM

- GW modeling of Parent Fluen sulfone Alone

PRZM

- GW (version 1.07) model inputs for fluensulfone alone are listed in Table 2 . The outputs are presented in Table 3 . Three use pattern schemes are represented.3

Table 2

. PRZM

- GW Input Parameters for Fluensulfone Alone

. Input Parameter Value Justification Source

Applications per

Year @ Application

Rate [1] 4 @ 1.008 kg/ha

[2] 3 @ 1,344 kg/ha [3] 2 @ 2.106 kg/ha Values follow label directions Proposed Label

Application Dates

and Intervals Assuming 1 st

application at Spring (March 15), followed by monthly interval, except for the third scheme with only two applications, the

interval is 6 months Values are within the application windows, following label

directions Proposed Label

Hydrolysis Half

- life 0 Stable at pH 4, 7 and 9 MRID 4 8574718

Aerobic Soil

Metabolism

Half

- life 17.08 days 90 th percentile confidence bound

on the mean of six half

- lives: 8.05, 9.12, 9.53, 11.9, 15.0, and

25.4 MRID 48574823

Organic Carbon

Partition Coefficient (K OC ) 192 L/kg OC Mean value of 154, 157, 172, 203,

and 275 MRID 4 8574833

Table 3 . PRZM

- GW Output for Fluensulfone Alone

Modeled

Scenario Max. Daily Conc. (μg/L) Mean Breakthrough Time (yrs) Post

- breakthrough Mean (μg/L)

DMV corn [1] 2.96

9.14 2.41

[2] 3.66 2.87

[3] 10.9 7.42

FL citrus [1] 15.5

7.25 13.2

[2] 15.5 13.6

[3] 11.1 9.73

FL potato [1] 0.0019

13.03 0.000892

[2] 0.00244 0.00108

[3] 0.00491 0.00219

GA peanut [1] 1.08

12.04 0.86

[2] 1.17 0.806

[3] 2.2 1.71

NC cotton [1] 0.679 10.22 0.479

[2] 0.568 0.4454

Modeled

Scenario Max. Daily Conc. (μg/L) Mean Breakthrough Time (yrs) Post

- breakthrough Mean (μg/L)

[3] 3.83 2.61

WI corn [1] 20.5

13.54 16.4

[2] 19.8 16.6

[3] 20.3 16.4

A Maximum values are in bold.

PRZM

- GW modeling of Degradate Methyl S ulfone Alone

PRZM

- GW model inputs for methyl sulfone alone are listed in Table 4 . The outputs are presented in Table 5

.

Table 4

. PRZM

- GW Input Parameters for Methyl Sulfone Alone

. Input Parameter Value Justification Source

Applications per

Year @ Application

Rate [1] 4 @0.0751 kg/ha

[2] 3 @ 0.1001 kg/ha [3] 2 @ 0.1502 kg/ha Values follow label directions Proposed Label

Application Dates

and Intervals Assuming 1 st

application at Spring (March 15), followed by monthly interval, except for the third scheme with only two applications, the

interval is 6 months Values are within the app lication windows, following label

directions Proposed Label

Hydrolysis Half

- life 0 Assumed stable Absence of data

Aerobic Soil

Metabolism

Half

- life 45.3 days 90 th percentile confidence bound

on the mean of three half

- lives: 34.2, 41.3, and 44 days MRID 48574829

Organic Carbon

Partition Coefficient (K OC ) 27.2 L/kg OC Mean value of 14.3, 17.5, 26.3, 27.5, and 50.5 MRID 4 8574834

Corrected for max imum detection value (7.45%) of methyl sulfone in the aerobic soil metabolism study

, as fluensulfone equivalent

.

Table 5 . PRZM

- GW Output for Methyl Sulfone Alone

Modeled

Scenario Max. Daily Conc. (μg/L) Mean Breakthrough Time (yrs) Post

- breakthrough Mean (μg/L)

DMV corn [1] 22 3.82 18.25

Modeled

Scenario Max. Daily Conc. (μg/L) Mean Breakthrough Time (yrs) Post

- breakthrough Mean (μg/L)

[2] 24.2 20.7

[3] 30.1 26.2

FL citrus [1] 33.5

2.71 26.3

[2] 33.9 26.5

[3] 29.4 23.3

FL potato [1] 6

3.11 3.35

[2] 6.73 3.53

[3] 5.85 4.22

GA peanut [1] 9.37

4.56 7.96

[2] 9.61 7.57

[3] 9.69 8.38

NC cotton [1] 13.6

6.04 10.3

[2] 12.4 9.83

[3] 19.9 17.8

WI corn [1] 41.4

7.49 34.8

[2] 41.2 34.6

[3] 39.2 33.8

A Maximum values are in bold.

Combining Results of Parent Fluensulfone and Degradate Methyl Sulfone

The resulting EDWCs of fluensulfone and methyl sulfone combined are derived by adding the

contents of Table 3 and Table 5

. Table 6 shows the final water values based on ground water

sources.

Table 6

. Final Results of EDWC

Modeled

Scenario Max. Daily Conc.

(μg/L) Post

- breakthrough

Mean (μg/L)

DMV corn [1] 24.96 20.61

[2] 27.86 23.57

[3] 41 33.62

FL citrus [1] 49 39.5

[2] 49.4 40.1

[3] 40.5 33.03

FL potato [1] 6.00 3.35

[2] 6.73 3.53

[3] 5.85 4.22

GA peanut [1] 10.45 8.82

[2] 10.78 8.38

[3] 11.89 10.096

Modeled

Scenario Max. Daily Conc.

(μg/L) Post

- breakthrough

Mean (μg/L)

NC cotton [1] 14.28 10.78

[2] 12.97 10.28

[3] 23.73 20.41

WI corn [1] 61.9 51.2

[2] 61 51.2

[3] 59.5 50.2

A Maximum values are in bold.

The combined EDWCs of 61.9 μg/L and 51.2 μg/L, respectively for acute and chronic concerns are less than the values provided by the previous drinking water assessment for cucurbits and fruiting vegetables.