EPA REGISTRATION DIVISION CO MPANY NOTICE OF FILING FOR

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER

EPA Registration Division contact: Mr. Jim Tompkins, 703-305-5697

Valent U.S.A. Corporation

8F7509

EPA has received a pesticide petition (8F7509) from Valent U.S.A. Corporation, 1600 Riviera Avenue, Suite 200, Walnut Creek, CA 94596 (EPA Company #59639) 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 by establishing a

tolerance for residues of the herbicide chemical bispyr ibac-sodium, benzoic acid, 2,6- bis-((4,6-dimethoxy-2-pyrimidinyl)oxy)-, sodium salt, and its des-methyl metabolite, sodium 2-(4,6-dimethoxypyrimidin-2-yl)oxy -6-(4-hydroxy-6-methoxypyrimidin-2-yl)

benzoate in or on the raw agricultural commodity freshwater fish tissue at at 0.01 part per million (ppm). EPA has determined that the petition contains data or information regarding the elements set fo rth in section 408 (d)(2) of FDDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data supports granting of the petition. Additional da ta may be needed before EPA rules on the petition.

A. Residue Chemistry

1. Plant metabolism. The metabolism of bispyribac-sodium in crop plants has been reported previously and is adequately understood for the purpose of granting the proposed tolerances.

2. Analytical method. Practical analytical methods for detecting and measuring levels of bispyribac-sodium and its metabolites have been developed and validated in/on all appropriate plant and anim al matrices. An analytical method for detecting bispyribac-sodium and its des meth yl metabolite (KIH 2023) in fish tissue has been submitted with this petition. The LOQ of bispyribac-sodium and the metabolite in the analytical method fo r fish tissue is 10 ppb (0.01 ppm), which will allow monitoring for residues at the levels proposed for the tolerances.

3. Magnitude of residues. A 28-day magnitude of the residue study was conducted with bluegill sunfish, Lepomis macrochirus and channel catfish, Ictalurus

punctatus . The study was performed at 2X the proposed application rate for bispyribac-sodium aquatic use to assess th e potential accumulation of bispyribacsodium and its des-methyl metabolite in fish tissue. Total bispyribac-sodium and des-methyl metabolite residues in bluegi ll and catfish tissue at 4 hours after application were measured at <0.01 ppm. Total bispyribac-sodium residues in2

bluegill and catfish tissue measured at day 1, 3, 7, 14, 21, and 28 days after dosing were all <0.01 ppm. Therefore, accounting for the 2X study dose rate, adequatedata exist to support the proposed tolerance of the combined residue of bispyribacsodium parent and the des-methyl metabo lite of 0.01 ppm in freshwater fish tissue.

B. Toxicological Profile

1. Acute toxicity. The toxicological profile a nd toxicological endpoints for bispyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were identified for bispyribac-sodium

.

2. Genotoxicty. The toxicological profile a nd toxicological endpoints for bispyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were identified for bispyribac-sodium.

3. Reproductive and developmental toxicity. The toxicological profile and toxicological endpoints for bi spyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (Volume 66, Number 181. No acute toxicity endpoints of con cern were identified for bispyribac-sodium.

4. Subchronic toxicity. The toxicological profile and toxicological endpoints for bispyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were identified for bispyribac-sodium.

5. Chronic toxicity. The toxicological profile and toxicological endpoints for bispyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were iden tified for bispyribac-sodium.

6. Animal metabolism. The toxicological profile and toxicological endpoints for bispyribac-sodium supporting this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were identified for bispyribac-sodium.

7. Metabolite toxicology

. The toxicological profile and toxicological endpoints for bispyribac-sodium supportin g this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were iden tified for bispyribac-sodium.

8. Endocrine disruption

. The toxicological profile and toxicological endpoints for bispyribac-sodium supportin g this petition for tolerances was published in the Federal Register on September 18, 2001 (V olume 66, Number 181. No acute toxicity endpoints of concern were iden tified for bispyribac-sodium.3

C. Aggregate Exposure

1. Dietary exposure. For the aggregate assessment, average daily dietary exposures (i.e., estimates of chronic di etary exposure) are aggregated with swimming exposures from the day of ex posure (i.e., assuming 45 ppb bispyribacsodium in water). Residential dietary and post-application recreational swimming exposures were aggregated and assessed agai nst the short- and intermediate-term oral endpoint of 100 mg/kg/d. Tota l estimated aggregate exposures are 0.000560 mg/kg/d for adult females and 0.00106 mg/kg/ d for children. Corresponding MOEs are 178,000 for adult females and 94,400 for children. Exposure estimates for drinking water were made based upon the drinking water EEC’s calculated using the proposed aquatic use pattern of bisp yribac-sodium. MOE’s were all greater than 100, so it is concluded that antici pated aggregate exposures to bispyribacsodium as conservatively esti mated here are not of concern.

i. Food. Acute - No acute toxicity endpoint of concern was identified for bispyribac-sodium, therefore, no acute di etary risk assessment was performed. b Chronic - Chronic dietary exposure for the general U.S. population is 0.000301 mg/kg/d (0.3% cRfD). Thus, chronic dietar y exposures resulting from the proposed aquatic use of bispyribac-sodium are not of concern

.

ii. Drinking water. A modified tier I rice model utilized previously by EPA was used as the basis for estimating dr inking water EECs resulting from the proposed bispyribac-sodium aquatic uses. The rice model was modified to calculate initial EECs for water bodies of several depths following either surface or subsurface applications of bispyribac-s odium resulting from the proposed use patterns, including a single application and four applicatio ns at the minimum retreatment interval of 30 days. The dr inking water EECs are based on total bispyribac-sodium residues (parent bispyribac-sodium plus the des-methyl degradate). The estimated maximum peak concentration is 60 ppb, assuming a 0.3 meter deep water body treated with four surface applications at 0.1 lb ai per surface acre. When four surface applications are made at 0.1 lb ai per surface acre with a 30-day interval, the annual average concentration is estimated to be 14 ppb for a 0.3 meter deep water body. The estimated lo ng-term residue in treated water bodies (~14 ppb) is greater than EPA’s surface wa ter estimate of 0.32 ppb for the existing rice use, so the chronic dietary assessmen t includes residues of 14 ppb. Potential residues of bispyribac-sodium in drinking water account for the vast majority of human dietary exposure, contributing 98% of exposure for the U.S. population and 98.5% of exposure for all infants

.

2. Non-dietary exposure

. Bipsyribac-sodium is intentionally added to water bodies at concentrations of up to 45 ppb. People swimming in treated water bodies may therefore be exposed to bispyribac -sodium. Exposures for recreational swimming have been modeled using SWIM ODEL. Dermal, aural and inhalation exposures were negligible. Total daily exposure on the day of application was4

0.000281 mg/kg/d for adult females and 0.000767 mg/kg/d for children. Assessed against the short- and intermed iate-term incidental oral toxicity endpoint of 100 mg/kg/d, MOEs were 356,000 and 130,000 for adult females and children, respectively. Thus, conservatively esti mated exposures to bispyribac-sodium resulting from potential swimming exposu re to the maximum application rate on the day of treatment are not of concern

.

D. Cumulative Effects

Section 408(b)(2)(D)(v) requires that the Agency must consider "available information" concerning the cumulative effe cts of a particular pesticide's residues

and "other substances that have a commo n mechanism of toxicity." Available

information in this context include not on ly toxicity, chemistry, and exposure data, but also scientific policies and methodologies for understanding common mechanisms of toxicity and conducting cu mulative risk assessments. Although the Agency has some information in its file s that may turn out to be helpful in eventually determining wheth er a pesticide shares a common mechanism of toxicity with any other substances, EPA does not at this time have the methodologies to resolve the complex scientific issues concerning common m echanism of toxicity in a meaningful way for most registered pesticides.

E. Safety Determination

1. U.S. population. i. Acute Risk. No assessment performed. ii. Chronic Risk. Chronic dietary (food + drinking water) ex posure for the general U.S. population is 0.000301 mg/kg/d (0.3% cRfD). Thus, there is no concern for chronic risk in the US population from dietary exposure to bispyribac-sodium.

2. Infants and children

. i. Safety Factor for Infants and Children. EPA has determined that the special 10x SF to protect infants and children should be removed [Federal Register of March 31, 2004 (69 FR 16823) (FRL-7351-2)]. The FQPA factor has been removed because developmental toxicity and offspring toxicity NOAELs/LOAELs are well charac terized; there is a well-defined doseresponse curve for the cardiovascular effects; and the endpoints of concern used for overall risk assessments are appropriate for the route of exposure and population subgroups.

ii. Acute Risk. No acut e endpoint has been identified for infants and children. Therefore, no assessment of acute exposure from food to this subgroup is required. iii. Chronic Risk. Chronic dietary exposures to bispyribac-sodium range from 0.000421 mg/kg/d (0.4% cRfD) for children aged 3-5 years old to 0.000982 mg/kg/d (1.0% cRfD) for all infants. Thus , chronic dietary exposures to infants and children resulting from the proposed aqua tic use of bispyribac-sodium are not of

concern.

F. International Tolerances5

Bispyribac-sodium has not been evaluated by the JMPR and there are no Codex Maximum Residue Limits (MRL) fo r bispyribac-sodium. MRL values have been established on rice grain to support the use of bispyribac-s odium on rice in the following countries:

US 0.02 ppm

Mexico 0.02 ppm Japan 0.1 ppm Korea 0.1 ppm Brazil 0.01 ppm Malaysia: 0.05mg/kg Rice (milled or polished) Russia: 0.1mg/kg