UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

MEMORANDUM 

DATE: June 19, 2013 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: Tebuconazole: Clarification on Percent Crop Treated Values Used in Dietary 

Assessments. 

PC Code: 128997 

Decision No.: 464543 

Petition No.: 2E8012 

Risk Assessment Type: Single ChemicaV Aggregate 

TXRNo.: NA 

MRIDNo.: NA 

From: Barry O'Keefe, Biologist 

Christine Olinger, Chief 

DP Barcode: 412582 

Registration No.: 264-752,264-748 

Regulatory Action: Tolerance Petition 

CaseNo.: NA 

CAS No.: 107534-96-3 

40 CFR: §180.474 

TO: Sidney Jackson/Barbara Madden, RM Team 05 

Risk Integration, Minor Use and Emergency Response Branch 

Registration Division (7505P) 

HED recently completed a human health risk assessment to support a crop group conversion 

(Fruiting Vegetables 8-1 0) as well as tolerance increases needed after submission of condition of 

registration data (B. O'Keefe, D402457, 1/31/13). Since minimal changes were needed for the 

dietary risk assessment, HED slightly modified an existing dietary risk assessment that relied 

upon percent crop treated (PCT) and percent crop treated -new (PCTn) estimates from 2006. 

The Registration Division has asked HED to compare the PCT values used in the assessment to 

the most recent estimates available (20 11) to ensure that dietary exposure is not underestimated. 

Note that the dietary assessment (DP408526, M. Negussie, 1129/13) is partially refined with 

percent crop treated estimates as well as monitoring data for a few crops, while tolerance values 

and field trial data were used for the remaining crops. 

A comparison of the PCT adjustments in the dietary risk assessment and the maximum and 

average PCT estimates from the most recent screening level usage analysis (SLUA) available 

(2011) are presented in Table 1. The maximum estimates are used for acute dietary exposure 

assessments and the average values are used in chronic assessment. The PCT estimates for 

grapes, nectarines, peaches, and peanuts are based on the 2006 SLUA, while the estimates for 

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apricots, apples, cherries, hops, plums and turnips are based on PCTn estimates, since they were 

not registered at the time of the assessment. HED assumed 100% crop treated for the remaining 

commodities: almonds, asparagus, banana, barley, dry bean, snap bean, nuts, coffee, field com, 

beets, garlic, leeks, tropical fruits, pumpkin, sunflower, wheat, squash, soybean, fruiting 

vegetables, and livestock commodities. While there were a few crops with slight increases in 

PCT values (peanut and peach maxima; and grape average), HED believes that the overall 

exposure assessment is conservative and is likely to be an overestimate for the following reasons: 

i) 100% crop treated was assumed for several commodities including some with high dietary 

consumption (e.g. soybeans, wheat), where the 2011 SLUA reflects a much lower usage rate; and 

ii) PCTn values were used for several registered crops, and the 2011 usage data indicates much 

lower relative usage. Furthermore, the attached critical commodity contribution analysis for 

children ages 1-2, the most highly exposed subgroup, demonstrates that the greatest contributors 

to the exposure are fruiting vegetables and drinking water. 

Table 1. Comparison of Percent Crop treated (PCT) Estimates Used in the Tebuconazole Dietary 

Assessments 

Commodity Acute PCT Used Chronic PCT Used in 2011 SLUA 2011 SLUA 

in Assessment Assessment Maximum Average 

Commodities for Which PCT is based on 2006 SLUA 

Grapes 25 15 25 20 

Nectarines 25 20 25 20 

Peaches 20 15 25 15 

Peanuts 45 35 50 35 

Commodities for Which PCT is based on 2006 PCTn 

Apricots 56 43 20 5 

Apples 44 41 <2.5 <1 

Cherries - babyfood 42 37 45 35 

Cherries - all other 100 66 45 35 food forms 

Hops 64 64 5 N/C 

Plums 26 24 <5 <2.5 

Sweet Com 22 14 NR NR 

Turnips 68 44 NR NR 

Commodities with Assumption of 100% CT and Included in 2011 SLUA 

Almond 100 100 <2.5 <1 

Asparagus 100 100 10 5 

Barley 100 100 5 5 

Beans, Green 100 100 <2.5 <1 

Soybeans 100 100 <2.5 <1 

Wheat 100 100 5 5 

NR =No use reported 

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Attachment. Critical Commodity Contribution Analysis for Children Ages 1-2. 

US EPA Ver. 3 . 16, 03-08 -d 

DEEM-FCID Chronic ana l ysis for TEBUCONAZOLE NHANES 2003-2008 2-day 

Residue file name: C:\Documents and Settings\colinger\My 

Documents\$RAB3\Chemicals\Tebuconazole\Di e tary\TEBUCONAZOLEFOOD_WATERCHRONIC20 13_TOL_BarleyCant 

WATER.R08 

Adjustment factor #2 used. 

Anal ysi s Date 05-16-2013/20:24:21 Residue file dat ed: 01-17 - 2013/10:23:16 

Refer ence dose (RfD, Chronic) = .029 mg/kg bw/day 

COMMENT 1: Food + H20 Additional data- Barley and Cantal oupe and Crop Gr oup Expansion to 8-10 

Critical Commodity Contribution Anal ysis for 

Children 1 - 2 

Total Exposure =.0042001 mg/kg bw/day 

Crop groups with total exposure contribution > 2% 

Foods/Foodforms with exposure contribution > 1% 

Crop group 

Food 

Foodform 

----------Exposure Analysis--------

mg/kg % of Total Per cent 

body wt/day Exposure of RfD 

Crop Gr oup = (8) Fruit ing Vegetabl es 

Pepper, bell (0802270000): 

FoodForm N/S 

Tomato (0801375000) : 

FoodForm N/S 

Tomato, paste (0801376000): 

FoodForm N/S 

Tomato, pur ee (08013 77000) : 

FoodForm N/S 

Tomat o, juice (0801379000 ) : 

FoodForm N/S 

Total for crop group 

Crop Group = (SA) Tomato 

Tomato (0801375000) : 

FoodForm N/S 

Tomato, paste (0801376000): 

FoodForm N/S 

Tomato, puree (0801377000 ) : 

FoodForm N/S 

Tomato, juice (0801379000 ) : 

FoodForm N/S 

Total for crop group 

Crop Group = ( 8B) Bell Pepper 

Pepper, bell (0802270000): 

FoodForm N/S 

Total for crop group 

Crop Group = (15) Cereal Grains 

Oat, g r oats/rolled oats (1500233000) : 

FoodForm N/S 

Wheat, flour (1500402000): 

FoodForm N/S 

Total for crop group 

Crop Group = (86) Water 

Water, direct, all sources (8601000000): 

0.0000494 

0.0006466 

0.0001165 

0.0002837 

0.0002507 

0.001381 2 

0.0006466 

0.0001165 

0.0002837 

0.0002507 

0 .001331 6 

0.0000494 

0 .0000495 

0.0000832 

0.0005587 

0. 0007218 

FoodForm N/S 0 . 0011464 

Water, indirect, all sources (8602000000): 

FoodForm N/S 0.0006357 

1.18% 0. 1 7% 

1 5.39% 2 . 23% 

2. 77% 0 . 40% 

6.76% 0.98% 

5.97% 0.86% 

32.88% 4 . 76% 

1 5 . 39% 2.23% 

2. 77% 0.40% 

6.76% 0.98% 

5. 97% 0.86% 

3 1.70% 4.59% 

1.18% 0. 1 7% 

1.18% 0.17% 

1.98% 0.29% 

13 . 30% 1.93% 

17 .19% 2.49% 

27.29% 3.95% 

15.14% 2.19% 

Total for crop group 0.0017821 42.43% 6 .15% 

Page 3 of4 
Crop group 

Food 

----------Exposure Analysis--------

mg/kg t of Total Percent 

Food form body wt/day Exposure of RfD 

Crop Group = (86A) Direct Water 

Water, direct, a ll sources (8601000000 ) : 

FoodForm N/S 0.0011464 27.29% 3.95t 

---------- ---------- Total for crop group 0.0011464 27.29% 3.95% 

Crop Group = (86B) Indirect Water 

Water, indirect, all sources (8602000000): 

FoodForm N/S 0.0006357 15.14% 2.19t 

---------- ---------- Total for crop group 0 . 0006357 15.14% 2.19% 

Total for crop groups l isted above : 0. 0038851 92.50% 13.4% 

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