UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES,

AND TOXIC SUBSTANCES

MEMORANDUM

Date: 04-NOV-2009

SUBJECT: AMENDMENT TO: Spiromesifen. Human-Health Risk Assessment for

Request to Reduce Rotational Crop Plantback Interval (PBI) for Bulb Vegetables

(Crop Group 3). DP#: 363706.

PC Code: 02487 5

Decision No.: 397603

Petition No.: 8F7398

Risk Assessment Type: Single Chemical

Aggregate.

TXRNo.: NA

MRIDNo.: NA

DP Barcode: 0 370274

Registration Nos.: 264-719 & 264-850

Regulatory Action: Amended Section 3

Case No.: NA

CAS No.: 283594-90-1

40 CFR: §180.607

FROM:

THROUGH:

TO:

Sarah J. Levy, Chemist x3 /:7{'

Robert Mitkus, Ph.D., Toxicologist

Risk Assessment Branch 1 (RAB1)

Health Effects Division (HED) (7509P)

George F. Kramer, Ph.D., Branch Senior Chemist ::;i "- -"'--- Dana Vogel, Branch Chief . 1:r-::.-__ - _ RABl/HED (7509P) / ,/-' --

Jennifer Gaines/John Hebert (RM Team 07)

Insecticide Branch/Registration Division (RD) (7505P)

The last risk assessment for spiromesifen was conducted on II-JUN-2009 (Memo, J. Tyler et al;

DP#: 363706). In this assessment, HED required the petitioner, Bayer CropScience, to submit

confirmatory residue analytical method data as a requirement for granting a Section 3

amendment. The petitioner had to confirm that the data-collection method used in the extensive

rotational crop study on onion adequately recovers residues of conjugates containing the 4-

hydroxymethyl moiety. Bayer has now submitted data in which residues of one ofthe moieties

were found. Bayer has proposed changing the proposed tolerance from 0.07 ppm to 0.09 ppm

for inadvertent residues inion vegetable, bulb (crop group 3-07). HED concurs with this

proposed tolerance; therefore, HED has revised the last dietary risk assessment to reflect this

tolerance increase for this crop group only. This is the only change made to the last spiromesifen

risk assessment (Memo, J. Tyler, II-JUN-2009; DP# 363706). The following paragraphs and/or

sections can replace the paragraphs and/or sections in the DP# 363706 memorandum.

Page I of 4
Introduction

Bayer CropScience has submitted a petition to amend the Oberon®2 Suspension Concentrate

(SC) Insecticide/Miticide [a 2 pound (lb) active ingredient (ai)/gallon (gal) SC formulation of

spiromesifen ((2-oxo-3-(2,4,6-trimethylphenyl)-I-oxasp iro[4.4]non-3-en-4-yl 3,3-

dimethylbutanoate))] and Oberon®4 SC Insecticide/Miticide (a 41b ai/gal SC formulation) labels

to include a 30-day PBI for bulb vegetables, crop group 3. In conjunction with the proposed

label amendment, Bayer has proposed the establishment of permanent tolerances for the

combined residues ofspiromesifen, its enol metabolite (4-hydroxy-3-(2,4,6-trimethylphenyl)-I -

oxaspiro[4.4]non-3-en-2-one), and its metabolites containing the 4-hydroxymethyl moiety,

calculated as parent compo und equival ents, inion the following commodities from crops grown

as rotational crops: vegetabl e, bulb, group 3-07 at 0.09 ppm.

1.0 Executive Summary

Dietary Risk Estimates (Food + Water): A conservative chronic dietary-risk assessment was

conducted using the Dietary Ex£osure Evaluation Model software with the Food Commodity

Intake Database (DEEM-FCID , Version 2.03). DEEM'M 7.81 default processing factors and

100% crop treated (CT) were assumed for all commodities; and tolerance-level residues were

assumed for all commodities except for the leafy-green and leafy-Brassica vegetable subgroups

(4A and 5B). For these subgroups, the residue values were adjusted to account for the metabolite

BSN 2060-4-hydroxymethyl (free and conjugated), which is a residue of concern in leafy

vegetables for risk assessment purposes only. Drinking water was incorporated directly into the

dietary exposure assessment using the chronic estimated drinking water concentration (EDWC)

of 188 ppb for groundwater generated by the Provisional Cranberry Model. The chronic dietary

risk assessment shows that the chro nic die tary risk estimates do not exceed HED's level of

concern [i.e., <100% of the chro nic population-adjusted dose (cPAD)]. For the genera l U.S.

population, the exposure for food and water utilized 50% ofthe cPAD. The chronic dietary risk

estimate for the highest exposed population subgroup, all infants <I year old, is 78% ofthe

cPAD.

Recommendations/or Tolerances: HED has examined the available toxicology and residue

chemistry databases for spiromesifen. Pending submission of a revised Section B, and submittal

ofreference standards, there are no residue chemistry issues that would preclude granting a

conditional Section 3 amendment for the 2 and 4 Ib/gal SC formulations ofspiromesifen to allow

a 30-day PBI for bulb vegetab les and establis hment of a tolerance for the inadvertent or indirect

combined residues ofspiromesifen, its enol metabolite, and its metabolites containing the 4-

hydroxymethyl moiety and its conjugates, calculated as the parent compound equivalents, as

follows:

Vegetable, bulb, group 3-07 0.09 ppm

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4.0 DIETARY EXPOSUREIRISK CHARACTERIZATION

The exposure pathways resulting from use ofthis chemical are dietary (food and drinking water)

and occupational; there are no residential uses. The residue chemistry data submitted in support

of the proposed uses were summarized in HED memoranda by J. Tyler (Memo, 6/11109; DP#

355619) and S. Levy (Memo, in progress; DP# 370549). The chronic dietary exposure

assessment was completed in a HED memorandum by S. Levy (Memo, 11 /04/09; DP# 370550).

4.1 Food Residue Profile

The submitted extensive field rotational crop trial data for green and bulb onion are adequate.

Bulb and green onions were planted - 30 days following application ofspiromesifen at the

maximum seasonal application rate to primary crops which may be rotated. The data support a

30-day PBI for the bulb vegetable crop group (group 3-07) and the proposed tolerance of 0.09

ppm for the indirect or inadvertent combined residues ofspiromesifen, its enol metabolite, and

its metabolites containing the 4-hydroxymethyl moiety and its conjugates, calculated as the

parent compound equivalents, inion the rotational crop commodities of bulb vegetables crop

group.

4.3 Chronic Dietary Exposure and Risk

A conservative chronic dietary assessment was conducted assuming tolerance-level residues for

all commodities except for the leafy-green and leafy-Brassica vegetable subgroups (4A and 5B).

For these subgroups, the residue values were adjusted to account for the metabolite BSN 2060-4-

hydroxymethyl (free and conjugated), which is a residue of concern in leafy vegetables for risk

assessment purposes only. DEEM'· 7.81 default processing factors and 100% CT were assumed

for all commodities . Drinking water was incorporated directly into the dietary assessment using

the chronic EDWC of 188 ppb for groundwater generated by the Provisional Cranberry Model.

The chronic dietary risk assessment shows that for all included commodities, the chronic

dietary risk estimates do not exceed HED's level of concern (l.e., <100% cPAD). For the

general U.S. population the exposure for food and water utilized 50% ofthe cPAD. The chronic

dietary risk estimate for the highest reported exposed population subgroup, all infants < I year

old, is 78% ofthe cPAD.

Page 3 of 4
The value for the highest exposed population IS bolded.

Table 4. Summary of Dietary (Food and Drinking Water) Exposure Risk for Spiromesifen.

Acute Dietary (95" Percentile) Chronic Dietary

Population Su bgroup Dietary Expos ure Dietary Exposure

(mg/kg/day) %aPAD (mg/kg/day) %cPAD

General U.S. Population 0.010916 50

All Infants «I year old) 0.017139 78

Children 1-2 years old 0.015491 70

Children 3-5 years old 0.014955 68

Children 6-12 years old NA 0.01 1114 51

Youth 13-19 years old 0.008928 41

Adults 20-49 years old 0.010600 48

Adults 50+ years old 0.010514 48

Females 13-49 years 0.010698 49 old

•

7.2 Residue Chemistry

860.1200 Directions for Use

• The proposed labels should be revised to include specify "bulb vegetables (crop group 3-

07)" instead of "bulb vegetables (crop group 3)" under the Rotational Plant-Back

Intervals sections.

860. 1340 Residue Analytical Methods

• The proposed analytical enforcement methods [Method 00631/MOOI (plants) and Method

110333 (rotational crops)] should be modified as detailed in the 11/15/07 petition method

validation memo (see DP# 30572 1).

860.1650 Submittal of Analytical Reference Standards

• Reference standards for the 4-hydroxymethyl metabolite and deut erated standards for the

enol and 4-hydroxymethyl metabolites must submitted to the ACB Repository.

cc: S. Levy, R. Mitkus

RDl: RABI Chemists (l1 -NOY-2009); RAB1 Branch (06-MAY-2009); G. Kramer (04-NOY-2009); D. Vogel (04-

NOY·2009)

S. Levy: S-10953: Potomac Yard 1 (PYI): (703) 305-0783: 7509P: RABI

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