1

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

PC Code: 071503 

 DP Barcode: D421066, 422286 

Date: September 17, 2014 

MEMORANDUM 

 

 

SUBJECT: Tier I Drinking Water Exposure Assessment in Support of the Proposed IR-4 New Use of 

Fludioxonil on Carrots and the Crop Group Conversion for Stone Fruit Group 12-12 and 

the Proposed Section 3 New Seed Treatment Use of Fludioxonil on Rapeseed Subgroup 

20A 

TO: Bill Wassell, Residue Chemist 

 Billy Smith, Branch Chief 

 Risk Assessment Branch I 

 Health Effects Division (7509P) 

 and 

 AWillis Ertman, Risk Manager Reviewer 

 Barbara Madden, Minor Use Team Leader 

 Risk Integration, Minor Use, and Emergency Response Branch 

Registration Division (7505P) 

 and 

 Erin Malone, Risk Manager Reviewer 

Shaja Joyner, Product Manager 

 Fungicide Branch 

Registration Division (7505P) 

 

FROM: Cheryl Sutton, Ph.D., Environmental Scientist 

 Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P)

REVIEWED Elyssa Arnold, Acting Risk Assessment Process Leader 

BY: Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P)

APPROVED Sarah Winfield, Acting Branch Chief

BY: Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P) 

The Environmental Fate and Effects Division (EFED) has completed the Drinking Water Assessment 

(DWA) for the Interregional Research Project No. 4 (IR-4) Center for Minor Crop Pest Management’s 

minor use request for the post-harvest use of fludioxonil (CAS No. 131341-86-1) on carrots, and for the 

crop group conversion for Stone Fruit Group 12-12. This DWA also covers the proposed new seed 
2

treatment use for Rapeseed Subgroup 20A. Product labels associated with this review are Maxim® 4FS 

(EPA Reg. No. 100-758) and Scholar SC (EPA Reg. No. 100-1242). 

Fludioxonil post-harvest (dip/drench) use on carrots is proposed for the control of white mold/sclerotinia 

rot. A DWA has previously been conducted for the IR-4 in-field use of fludioxonil on carrots (DP 

Barcodes: 285197, 285514, 286372, 286717; 1/2/2003)1

. In that assessment, the registered 

application rate for carrots of four applications of 0.219 lb a.i./A at 7- to 10-day intervals for a 

maximum annual application of 0.88 lb a.i./A/yr is addressed. Estimated Drinking Water 

Concentrations (EDWCs) are not calculated for the carrot use in that assessment because the use rate 

is lower than previously assessed rates. The proposed post-harvest use rate on carrots is as a dip 

containing 0.24 lb a.i./100 gallons. 

Fludioxonil post-harvest use on stone fruits is proposed for the Stone Fruit Group 12-12 based on 

prior registration on multiple stone fruits for the control of various rots. The proposed post-harvest 

use rate on stone fruits is as a dip containing 0.24 lb a.i./100 gallons or as an in-line aqueous or fruitcoating spray with a solution containing 0.24-0.48 lb a.i. (solution concentration not stated) per 

200,000 pounds fruit. 

Fludioxonil seed treatment is proposed for Rapeseed Subgroup 20A, expanding on the current seed 

treatment use on rapeseed and canola varieties, for protection against seed-borne and soil-borne fungi 

that cause decay, damping-off, and seedling blight. The proposed rate is 0.08-0.16 fl oz of product 

per 100 lb of seed (or 0.0025- 0.005 lb a.i./100 lb seed). At the maximum seeding rate of 8.2 lb 

rapeseed/A, the proposed maximum rate is 0.00041 lb a.i./A. 

A new DWA was not conducted for the proposed new post-harvest uses stated above. Because EDWCs 

are based on the crop use with the maximum application rate, the previously reported EDWCs for 

fludioxonil use on field grown ornamentals remain the recommended values for the human dietary 

assessment. These values are reported in Table 1. Complete details on the determination of these values 

may be found in “Tier I Drinking Water Assessment for the Fludioxonil Proposed Use on Ornamentals” 

(DP Barcode: 364264; 6/22/2009)2

 and in a subsequent DWA for additional IR-4 uses (DP Barcodes 

395364, 389616; 10/27/2011)3

. It is noted that while EFED now has an additional model (PRZM-GW) 

available for the determination of EDWCs for groundwater sources of drinking water, the contribution of 

groundwater relative to surface water EDWCs is negligible, and additional modeling was not conducted. 

 

1

 USEPA, 2003. EFED Water Memorandum for the IR-4 Requests for the use of Fludioxonil (Switch 62.5 WG®) on 

Brassica, Carrot, Herb Subgroup 19A, and Lychee. Memorandum from John Ravenscroft, Jr., Environmental Fate 

and Effects Division, to Hoyt Jamerson and Shaja Brothers, Registration Division, dated January 2, 2003. DP 

Barcodes 285197, 285514, 286372, 286717. Office of Pesticide Programs, U.S. Environmental Protection Agency. 

2

 USEPA, 2009. Tier I Drinking Water Assessment for the Fludioxonil Proposed Use on Ornamentals. 

Memorandum from Chuck Peck, Environmental Fate and Effects Division, to Mary Waller and Lisa Jones, 

Registration Division, dated June 22, 2009. DP Barcode 364264. Office of Pesticide Programs, U.S. Environmental 

Protection Agency. 

3

 Tier I Drinking Water Assessment in Support of Proposed or Amended Tolerances for the Fludioxonil IR-4 Uses 

on Ginseng; Onion Subgroup 3-07 A and B; Berry and Small Fruit Subgroups 13-07 A, B, F and G; Fruiting 

Vegetable Group 8-10, Except Tomato; Tomato; Leafy Vegetable Except Brassica Subgroup 4A; Pome Fruit Group 

11-10; Citrus Group 10-10; Potato; Pineapple; Dragon Fruit; Avocado; Mango; Other Various Tropical Fruits. 

Memorandum from Cheryl Sutton, Environmental Fate and Effects Division, to George Kramer and Dana Vogel, 

Health Effects Division, dated October 27, 2011. DP Barcodes 395364, 389616. Office of Pesticide Programs, U.S. 

Environmental Protection Agency. 
3

Table 1. Maximum Tier I Estimated Drinking Water Concentrations in surface water based on 

fludioxonil use on field grown ornamentals at 2 lb ai/A/yr. 

DRINKING WATER SOURCE 

(MODEL USED) 

USE (rate modeled) MAXIMUM ESTIMATED DRINKING WATER 

CONCENTRATION (EDWC) (μg/L)

Groundwater (SCIGROW) 

Field grown ornamental (2 lbs. 

a.i./A/applic. x 1 applic.; total rate 

of 2 lb ai/A/yr ) 

Acute and Chronic 0.20 

Surface Water (FIRST) 

Field grown ornamental (2 lbs. 

a.i./A/applic. x 1 applic.; total 

rate of 2 lb ai/A/yr ) 

Acute 83.8 

Field grown ornamental (2 lbs. 

a.i./A/applic. x 1 applic.; total 

rate of 2 lb ai/A/yr ) 

Chronic 38.5