UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C. 20460

O FFICE O F CHEMICAL SAFETY AND P O LLUTI O N PREVENTI O N

PC code: 128997

DP Barcode: D38 5878

May 10 , 201 1

Memorandum

To: Cassi L. Walls, Ph.D.

Risk Assessment Branch 3

Health Effects Division, 7509P

Lisa Jones

Risk Manager Reviewer, RM 20

Registration Division, 7505P

From: William P. Eckel, Ph.D.

Senior Science Advisor, ERB6

Environmental Fate & Effects Division, 7507P

Through: Mark Corbin, Chief

Environmental Risk Branch 6

Environmental Fate & Effects Division, 7507P

Subject: Drinking Water Assessment for Tebuconazole: Fluopyram/Tebuconazole 400 SC

Fungicide (EPA Reg. No. 264

- RNOR)

EFED has examined the use rate table (attached) for the proposed tebuconazole

- fluopyram

combination product (Fluopyram/Tebuconazole 400 SC fungicide ) , containing 1.67 lb/gallon of each

active ingredient. The proposed tebuconazole use rates for all crops listed in the table are equal to, or

lower than, rates previously assessed for the single active ingredient tebuconazole products Elite 45

DF foliar fungicide (EPA Reg. No. 264

- 749) and Folicur 3.6F foliar fungicide (EPA Reg. No. 264

- 752).

The previous drinking water assessments ( D311610, D311622, D313985, D319241, D319245,

D332177, D332261, dated Feb. 7, 2007) and D 362939 (dated June 3, 2009) are therefore still

current. T he EDWCs from these two assessments are reproduced below for your convenience.EDWCs from Feb. 7, 2007 DWA

Table 1. Tebuconazole Estimated Drinking Water Concentrations from Surface Water Sources.

Scenario Application

Type/ Annual

Fungicide

Application Rate

(kg ai/ha) ) Estimated Drinking Water Concentrations (μg/L)

1 in 10 year annual

peak 1 in 10 year

annual mean 36 year annual

mean

FL Turf a aerially applie d

1.65 x 3 = 4.95 96.6 c 51.4 33.7

Commercial Ornamentals

simulated with PA turf b aerially applie d

0.56 x 8 = 4.48 77.4 59.0 d 46.2 d

P A ap ples a airblast

0.25 x 6 = 1.50 27.4 16.6 10.9

a

- Mo deled with the lowest non

- sand K D as the partition coefficient input parameter.

b

- Modeled with the average K OC a s the partition coefficient input parameter.

c

– It is the highest estimated DW peak concentration

. d

– These are the highest estimated DW annual mean concentration s.

EDWCs from June 3, 2009 DWA

Table 1. Maximum Estimated Drinking Water Concentrations (EDWCs) resulting from applications of

Tebuconazole on Fruiting Vegetables (Crop Gro up 8)

Drinking Water

Source (Model) Scenario

(first app date) Method 1 Application Rate

(interval between

applications) 1 in 10 yr

annual

peak (μg/L) 1 in 10 yr

annual mean

(μg/L ) 30 yr

annual

mean (μg/L )

Surface Water

(PRZM/EXAMS)

PCA = 0.87 2 PA Tomato

(September 03) A 6 app @ 0.225 lb. a.i./acre

(7 days) -- 16.97 12.14

FL Tomato

(April 03) G 47.23

-- --

Values denote maximum Estimated Drinking Water Concentrations (EDWCs)

1 For foliar applications, A = aerial application, G = ground application. All applications are liquid unless otherwise noted.

2 Adjustment Factors: PCA = Percent Crop Area

Note on Turf Uses : Label Uncertainties

A n ecological risk assessment including the new use of tebuconazole on turf was completed in 2006

( review dated 11 /2/06; D311610+)

. However, the turf new use was not granted at that time

.

Supplemental labeling for golf course turf and ornamentals use of tebuconazole was approved o n April 28, 20 1 0 for Tebuconazole 3.6F Fungicide (EPA Reg. No. 69361

- 2 7). At that tim e, a DWA

was not performed. T he use rates for golf course turf appear to be similar to those in the FL turf

scenario used to generate EDWCs for the DWA performed in 2007. However , the label is unclear

in its label directions for ornamentals (see table be low)

.Use Rate Analysis for Label 69361

- 27 Tebuconazole 3.6F Fungicide (3.6 lb a.i./gal)

Use site Maximum single

application rate Maximum No. of

Applications Minimum

Application

Interval Maximum Yearly

Use rate

Gol f Course turf 0.6 fl.oz./1000

sq.ft. =

0.74 lb/acre 6 28 days 3.6 fl.oz./1000

sq.ft. = 4.41

lb/acre

Field, Nursery &

Container

ornamentals &

Commercial and

Residential

Landscapes 4

– 10 fl.oz./acre

= 0.11

– 0.28

lb/acre Preventative: “at

least 3 times” or

for roses, “every

14

– 21 days

duri ng the

growing season”

Petal Blight: not

specified

Existing Disease:

“total of 3

applications” 14

– 21 days

“2

– 3 times per

week”

14 days 0.84 lb/acre or

more

Not specified

0.84 lb/acre

30 fl.oz./acre =

0.84 lb/acre 4 at highest rate Not specified 120

fl.oz./acre/year =

3.38 lb/acre/year

Calculations:

Golf Course: lb/acre = fl.oz/1000 sq.ft. x 3.6 lb/gal x gal/128 fl.oz. x 43560 sq.ft./acre

Ornamentals etc.: lb/acre = fl.oz./acre x 3.6 lb/gal x gal/128 fl.oz.

Attachment : (Use rate t able for Fluopyram/Tebuconazole 400 SC fungicide, and single active

ingredient tebuconazole products Elite 45 DF foliar fungicide (EPA Reg. No. 264

- 749) and Folicur

3.6F foliar fungicide (EPA Reg. No. 264

- 752).