Revised Addendum to Azoxystrobin Human Health Risk Assessment DP No. 428619 

UNITf:D STATES ENVI RONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: November 12, 2015 

OFFIC ~ OF 

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SUBJECT: Azoxystrobin. Revised Addendum to Human Health Aggregate Risk Assessment 

D42369 I and D418374, Dated 417/20 I 5, to Support a New Use on Quinoa. 

PC Code: 128810 

Decision No.: 495749 

Petition Nos.: 4£8319 

DP Barcode: 0428619 

Registration Nos.: 100-1178, 100-1324 

Regula tory Action: Section 3 Registration 

Risk Assessment Type: Single Chemical/Aggregate Case No.: 7020 

TXR No.: NA CAS No.: 131860-33-8 

MRID No.: NA 40 CFR: § 180.507 

FROM: 

T HROUGH: 

TO: 

Introduction 

Laura Nollen, Bi logis ~) o---- Vl/~ 1\/12 /1.0\5 

Risk Assessment Bran~l RAB 3) 

Health Effects Division (7509P) 

C

Don

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ine 

Wilbur, 

Olinger

Senior 

, Branch 

Chemist 

Chief 

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Risk Assessment Branch 3 (RAB 3) (/i'1 r-/ '- · 

Health Effects Division (7509P) 

Andrew Ertman, Biologist 

Barbara Madden, Biologist, Team Leader 

Minor Use Team 

Registration Division (7505P) 

This document provides an addendum to the recently-completed Health Effects Division (HED) 

human health assessment (0423691 and D418374, Kristin Rury, 417/2015) in order to assess an 

additional proposed tolerance and proposed registrations of a use of the fungicide, azoxystrobin, 

in or on quinoa grain. The revised addendum provides additional information regarding exposure 

and risk considerations. 

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Revised Addendum to Azoxystrobin Human Health Risk Assessment DP No. 428619 

Use Profile and Proposed Tolerance/Registration 

Azoxystrobin is a P-methoxyacrylate fungicide currently registered for use on a variety of field, 

vegetable, fruit, and nut crops as well as on ornamental plants and turf. It is also used to control 

mold on indoor surfaces. Its biochemical mode of action is inhibition of electron transport. 

HED recently completed a human health risk assessment for the proposed establishment of 

several tolerances of the fungicide azoxystrobin, associated with two pesticide petitions. 

A pesticide petition (PP# 4E8319) was previously submitted by the Interregional Research 

Project Number 4 (IR-4) to propose tolerances without U.S. registration for azoxystrobin in/on 

Ti palm, and to incorporate recent revisions to the crop group listings of the Stone Fruit Crop 

Group 12- 12 and Tree Nut Crop Group 14-12. IR-4 subsequently submitted an additional request 

associated with PP# 4E8319 on behalf of Hawaii, Montana, and Oregon, to establish a tolerance 

in or on quinoa grain at 3.0 parts per million (ppm). IR-4 also requested that quinoa be added to 

two registered end use products containing azoxystrobin: Quilt Xcel® Fungicide (EPA Reg. No. 

100-1178; Syngenta Crop Protection) and Quilt® Fungicide (EPA Reg. No. I 00-1178; Syngenta 

Crop Protection) to control downy mildew (Peronospora variabilis). A second petition, PP# 

3E8228, was submitted by Syngenta Crop Protection and included a proposal to add import 

tolerances without domestic registrations to the AmistarZtra SC label (Columbia) on coffee, to 

the Azoxystrobin Amistar WP 10% label (South Korea) on Asian pear, and to the Amistar 20 SC 

label (Japan) on tea. 

IR-4 has proposed label directions for quinoa that are nearly identical to those registered for 

barley grain, except that the reference to the Feekes growth stage 10.5 has been removed because 

quinoa is a pseudocereal rather than a grass. For both Quilt® and Quilt Xcel®, azoxystrobin may 

be applied to quinoa via ground or aerial equipment and at a maximum single application rate of 

14 fl. oz. product/ A, with no more than 2 applications per acre per season. Appl ications may be 

made no closer than a 14-day interval, and the restri cted entry interval (REI) listed on both 

products is 12 hours. 

No quinoa residue data have been submitted with this petition; rather, IR-4 has proposed to 

translate the data used to establish a tolerance on barley grain at 3.0 ppm in order to support a 

tolerance and registration for use on quinoa grain. The IR-4 proposal is supported by a recent 

recommendation of the Chemistry Science Advisory Council (ChemSAC). 

Chemistry Science Advisory Council (ChemSAC) Recommendations 

The HED Chem SAC recently implemented a policy to allow the translation of wheat or barley 

data to establish a tolerance in or on quinoa (ChemSAC Meetings, 5/27/2015 and 7/29/2015). 

ChemSAC recommended that data may be translated from cereal grains to quinoa, allowing for a 

quinoa registration without additional quinoa-specific residue data, if the following criteria are 

met: 

• There are established tolerances for residues in or on wheat, barley (in cases where a 

barley tolerance has been established at a higher tolerance than a wheat tolerance) or 

Cereal Grain Crop Group 15; and 

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Revised Addendum to Azoxystrobin Human Health Risk Assessment DP No. 428619 

• The proposed use pattern for quinoa is the same as the registered use pattern on wheat, 

barley, or Cereal Grain Crop Group 15. 

For azoxystrobin, the use patterns, treatment timing and label rates will be same as those for the 

registered use of azoxystrobin on barley grain. Therefore, translation from the existing data for 

the azoxystrobin use in or on barley grain to quinoa is appropriate, based on the similarity of 

cultural practices for quinoa and barley (as well as other cereal grains). 

Exposure and Risk Considerations 

There is no consumption of quinoa reported in the 2003-2008 data from the U.S. Department of 

Agriculture's (USDA's) National Health and Nutrition Examination Survey, What We Eat in 

America, (NHANES/WWEIA). Notwithstanding, because quinoa can be prepared like other 

whol e grains, such as rice and barley, and because it may be used to make flour in a manner 

similar to wheat and other cereal grains, the Agency concludes that quinoa will likely substitute 

in the diet for cereal grain foods, which, as discussed above, will contai n similar residues of 

azoxystrobin. Consequently, a significant increase in dietary exposure to residues of 

azoxystrobin from consumption of quinoa-containing foods is not antici pated. Since the use 

pattern for quinoa is consistent with that for wheat and barley, increased exposures to individuals 

through drinking water is not expected. Therefore, establishing tolerances on quinoa will not 

result in additional dietary exposure to azoxystrobin from food or drinking water sources. 

No changes to residential exposures will occur as a result of proposed use on quinoa. 

Based on the information provided above, HED conc ludes that the aggregate exposure and risks 

as a result of the proposed use on quinoa will not increase and will be the same as those 

estimated in previous HED risk assessments. 

Since the agronomi c practices for quinoa are known to be similar to those of wheat and barley, 

and existing occupational exposure assessments on wheat and barley are not of concern, these 

assessments are protective of the proposed use of azoxystrobin on quinoa. 

H ED Recommendations 

In the most recently-completed comprehensive risk assessment for azoxystrobin (0423691 and 

0418374, Kristin Rury, 4/7/20 15), the toxicity database was considered complete. Adequate 

residue data are avai lable to support the proposed use on quinoa grain, translated from barley 

grain, which have nearl y identical use patterns (except that the reference to the Feekes growth 

stage has been removed because quinoa is a pseudocereal rather than a grass). HED concludes 

that the aggregate exposures and risks will not increase for azoxystrobin as a result of the 

proposed use and will be the same as those estimated in the recentl y-completed HED risk 

assessment. No risks of concern were identified in those previous assessments. Occupational 

exposures and risks are also not of concern. Therefore, HED recommends establishing a 

permanent tolerance for residues of azoxystrobin in or on quinoa, grain at 3.0 ppm. Further, HED 

recommends granting the proposed registration of Quilt Xcel® Fungicide and Quilt® Fungicide 

on quinoa grain. 

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