COMPANY FEDERAL REGISTER DOCUMENT SUBMISSION

EPA Registration Division contact: Bethany Benbow (703) 347

- 8072

BASF Corporation

Petition# 0E7781

EPA has received a pesticide petition (0E7781) from BASF Corporation

, P.O. Box 13528, Research Tr iangle Park , NC 27709 proposing, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180.560 by amending the tolerance expression to establish combined residues of cloquintocet

- mexyl (ace tic acid, [(5

- chloro

- 8

- quniolinyl)oxy]

- , 1

- methylhexyl ester)(CAS Reg. No. 99607

- 70

- 2) and its acid metabolite (5

- chloro

- 8

- quinlinoxyacetic acid) when used as an inert ingredient (safener) in pesticide formulations containing either the herbicide clodinafop

- propargyl or pinoxaden in a 1:4 ratio of safener to active ingredient or in combination with the registered active ingredient dicamba in or on the following established raw agricultural commodities: wheat, grain at 0.10 parts per million (ppm), wheat, for age at 0.2 ppm, wheat, hay at 0.50 ppm, and wheat, straw at 0.10 ppm

. EPA has determined that the petition contains data or information regarding the elements set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated the sufficienc y of the submitted data at this time or whether the data supports granting of the petition. Additional data may be needed before EPA rules on the petition.

A. Residue Chemistry

1. Plant metabolism

. The metabolism o f cloquintocet

- mexyl in wheat is well understood, as was published previously in the Federal Register (April 19, 2000, V olume 65, N umber 76, page 20972

- 20976). Total residues in all crop samples are low. Metabolism involves primarily rapid hydrolysis of the parent to the resulting acid followed by conjugation.

2. Analytical method

. A practical analytical method for the determination of cloquintocet

- mexyl and its major plant metabolite CGA

- 153433 in wheat RACs has previously been published in the Federa l Register (April 19, 2000, (Volume 65, Number 76), page 20972

- 20976).

3. Magnitude of residues

. The magnitude of residue of cloquintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76), page 20972

- 20 976).2

B. Toxicological Profile

1. Acute toxicity

. Cloquintocet

- mexyl has a low order of acute toxicity. The acute toxicity profile of cloquintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (V olume 65, N umber 76 ) , page 20972

- 20976). The EPA has published the acute toxicity endpoints in the Federal Register (June 22, 2000 (Volume 65, Number 121), page 38757

- 38764).

2. Genotoxicty

. Cloquntocet

- mexyl was negative in all genotoxicity tests. The genotoxicity of cloq uintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976).

3. Reproductive and developmental toxicity

. Cloquintocet

- mexyl is not a reproductive or developmental toxicant. The toxicit y of cloquintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976). The EPA has published the reproductive and developmental toxicity endpoints in the Federal Register (June 22, 2000 (Volu me 65, Number 121), page 38757

- 38764).

4. Subchronic toxicity

. The subchronic toxicity profile of cloquintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976). The EPA has previously p ublished the subchronic toxicity endpoints in the Federal Register (June 22, 2000 (Volume 65, Number 121), page 38757

- 38764).

5. Chronic toxicity

. The chronic toxicity profile of cloquintocet

- mexyl was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976). The EPA has published the chronic toxicity endpoints in the Federal Register (June 22, 2000 (Volume 65, Number 121), page 38757

- 38764). The Agency classified cloquintocet

- mexyl as``not lik ely to be a human carcinogen''.

6. Animal metabolism

. The metabolism of cloquintocet

- mexyl in animals is well understood, as was published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976). In rats, approximately 50% of an oral dose of cloquintocet

- mexyl was rapidly absorbed through the gastrointestinal tract and excreted via urine and bile. The administered dose was excreted independent of sex and was essentially complete within 48 hours. Ninety

- five percent of the excre ted dose was associated with one metabolite, the acid residue of cloquintocet

- mexyl (5

- chloro

- 8

- quinlinoxyacetic acid , CGA

- 153433 ).

7. Metabolite toxicology

. The main metabolite in both plants and animals is 5

- chloro

- 8

- quinlinoxyacetic acid. As this is the main metabolite in rats, rabbits and mice, its toxicology has been tested throughout the toxicology database for cloquintocet

- mexyl. The toxicity of cloquintocet

- mexyl metabolites was discussed previously in the Federal Register3

(April 19, 2000, (Volu me 65, Number 76) , page 20972

- 20976).

8. Endocrine disruption

. There is no evidence that cloquintocet

- mexyl has any effect on endocrine function, as was discussed previously in the Federal Register (April 19, 2000, (Volume 65, Number 76) , page 20972

- 20976).

C. Aggregate Exposure

1. Dietary exposure

. BASF is not proposing any new tolerances or modifications to existing tolerances for cloquintocet

- mexyl. Therefore, the most recent EPA human health assessment for cloquintocet

- mexyl, “Human Health Risk Assessment for Cloquintocet

- mexyl for uses on Wheat and Barley” November 29, 2005, is applicable to the current notification. The US EPA has determined that an acute dietary assessment is only required for females ages 13

- 49. A suitable acute endpo int for the general population was not identified because there were no effects observed in the oral toxicity studies attributable to a single dose exposure. The acute population adjusted does for females is 1.0 mg/kg bw

- day (NOAEL = 100 mg/kg bw

- day, saf ety factor = 100. The chronic population adjusted does determined by the US EPA is 0.04 mg/kg bw

- day (NOAEL = 4.3 mg/kg bw

- day, safety factor = 100).

i. Food

. The acute dietary assessment for cloquintocet

- mexyl is a Tier 1 assessment because no data was used to refine the exposure estimate. The exposure estimate was determined using 100% crop treatment factors and tolerance level reidues for all commodities. The highest estimated acute drinking water estimated, 0.186 ppb, was included in the dietary ass essment conducted by EPA. The acute assessment is shown in Table 1.

Table 1. Summary of Acute Dietary Exposure Assessment (food + water) Considering All Crops with Established and Proposed Tolerances for Cloquintocet

- mexyl.

Population Subgroups Expo sure Estimate (mg/kg b.w./day) %aPAD

Females 13

- 49 0.000347 < 1 %cPAD = percent of chronic population adjusted dose Exposure estimates based on tolerance values, default processing factors, and 100% CT for all crops/commodities4

The chronic dietary assessment for cloquintocet

- mexyl is a Tier 1 assessment because no data was used to refine the exposure estimate. The exposure estimate was determined using 100% crop treatment factors and tolerance level reidues for all commodities. The highest estimat ed acute drinking water estimated, 0.005 ppb, was included in the dietary assessment conducted by EPA. The chronic assessment is shown in Table 2

Table 2. Summary of Chronic Dietary Exposure Assessment (Food + drinking water) Considering All Crops with Established and Proposed Tolerances for Cloquintocet

- mexyl Population Subgroups Exposure Estimate (mg/kg b.w./day) %cPAD
U.S. Population 0.000180 < 1 All Infants 0.000077 < 1 Children 1

- 2 years 0.000403 < 1 Children 3

- 5 years 0.000411 < 1 Children 6

- 1 2 years 0.000289 < 1 Youth 13

- 19 years 0.000176 < 1 Adults 20

- 49 years 0.000153 < 1 Adults 50+ years 0.000120 < 1 Females 13

- 49 0.000137 < 1 %cPAD = percent of chronic population adjusted dose Exposure estimates based on tolerance values, default p rocessing fac tors, and 100% CT for all crops/commodities

The results in Table 1 and 2 demonstrate there are no safety concerns for any subpopulation based on established and new uses, and the results clearly meet the FQPA standard of reasonable certaint y of no harm.

ii. Drinking water

. The US EPA Environmental Fact and Effects Division (EFED) has determined the higest EECs for the acute and chronic exposures. The acute EEC is 0.186 ppb and the chronic EEC is 0.005 ppb. These water EEC values were i ncluded in the dietary assessments referenced above.

2. Non

- dietary exposure

. Products containing the safener cloquintocet

- mexyl will be registered for agricultural uses only and will not be available for any residential or public uses. Therefore, t he aggregate risk is the sum of the risk from food and water.5

D. Cumulative Effects

Cumulative Exposure to Substances With a Common Mechanism of Toxicity. Section 408(b)(2)(D)(v) requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider "available information" concerning the cumulative effects of a particular pesticide's residues and "other substances that have a common mechanism of toxicity". A discussion of the availability of data for determination whet her cloquintocet

- mexyl has a common mechanism of toxicity with other substances was included in the Federal Register Tolerance Notice of June 22, 2000 (Volume 65, Number 121, page 38757

- 38764)

E. Safety Determination

1. U.S. population

. BASF has consid ered the potential aggregate exposure from food, and water exposure routes and concluded that aggregate exposure is not expected to exceed 100% of the chronic or acute reference dose and that there is a reasonable certainty that no harm will result to infa nts and children from the aggregate exposure to cloquintocet

- mexyl.

2. Infants and children

. BASF has considered the potential aggregate exposure from food, and water exposure routes and concluded that aggregate exposure is not expected to exceed 100% of the chronic or acute reference dose and that there is a reasonable certainty that no harm will result to infants and children from the aggregate exposure to cloquintocet

- mexyl.

F. International Tolerances

There are no international tolerances for the i nert (safener), cloquinocet

- mexyl