Pyroxasulfone; Pesticide Tolerances

Federal Register, Volume 79 Issue 117 (Wednesday, June 18, 2014)

Federal Register Volume 79, Number 117 (Wednesday, June 18, 2014)

Rules and Regulations

Pages 34629-34633

From the Federal Register Online via the Government Printing Office www.gpo.gov

FR Doc No: 2014-14251

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

EPA-HQ-OPP-2013-0673; FRL-9911-08

Pyroxasulfone; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation amends tolerances for residues of pyroxasulfone in or on corn, field, forage and corn, field, grain. K-I Chemical U.S.A. Inc. c/o Landis International, Inc. requested these amended tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective June 18, 2014. Objections and requests for hearings must be received on or before August 18, 2014, and must be filed in accordance with the instructions provided in 40 CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES: The docket for this action, identified by docket identification (ID) number EPA-HQ-OPP-2013-0673, is available at http://www.regulations.gov or at the Office of Pesticide Programs Regulatory Public Docket (OPP Docket) in the Environmental Protection Agency Docket Center (EPA/DC), West William Jefferson Clinton Bldg., Rm. 3334, 1301 Constitution Ave. NW., Washington, DC 20460-0001. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the OPP Docket is (703) 305-5805. Please review the visitor instructions and additional information about the docket available at http://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Lois Rossi, Registration Division (7505P), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460-0001; main telephone number: (703) 305-7090; email address: RDFRNotices@epa.gov.

SUPPLEMENTARY INFORMATION:

1. General Information

   1. Does this Action apply to me?

      You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. The following list of North American Industrial Classification System (NAICS) codes is not intended to be exhaustive, but rather provides a guide to help readers determine whether this document applies to them. Potentially affected entities may include:

      Crop production (NAICS code 111).

      Animal production (NAICS code 112).

      Food manufacturing (NAICS code 311).

      Pesticide manufacturing (NAICS code 32532).

   2. How can I get electronic access to other related information?

      You may access a frequently updated electronic version of EPA's tolerance regulations at 40 CFR part 180 through the Government Printing Office's e-CFR site at http://www.ecfr.gov/cgi-bin/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title40/40tab_02.tpl.

   3. How can I file an objection or hearing request?

      Under FFDCA section 408(g), 21 U.S.C. 346a, any person may file an objection to any aspect of this regulation and may also request a hearing on those objections. You must file your objection or request a hearing on this regulation in accordance with the instructions provided in 40 CFR part 178. To ensure proper receipt by EPA, you must identify docket ID number EPA-HQ-OPP-2013-0673 in the subject line on the first page of your submission. All objections and requests for a hearing must be in writing, and must be received by the Hearing Clerk on or before August 18, 2014. Addresses for mail and hand delivery of objections and hearing requests are provided in 40 CFR 178.25(b).

      In addition to filing an objection or hearing request with the Hearing Clerk as described in 40 CFR part 178, please submit a copy of the filing (excluding any Confidential Business Information (CBI)) for inclusion in the public docket. Information not marked confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA without prior notice. Submit the non-CBI copy of your objection or hearing request, identified by docket ID number EPA-HQ-OPP-2013-0673, by one of the following methods:

      Federal eRulemaking Portal: http://www.regulations.gov. Follow the online instructions for submitting comments. Do not submit electronically any information you consider to be CBI or other information whose disclosure is restricted by statute.

      Mail: OPP Docket, Environmental Protection Agency Docket Center (EPA/DC), (28221T), 1200 Pennsylvania Ave. NW., Washington, DC 20460-0001.

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      Hand Delivery: To make special arrangements for hand delivery or delivery of boxed information, please follow the instructions at http://www.epa.gov/dockets/contacts.html.

      Additional instructions on commenting or visiting the docket, along with more information about dockets generally, is available at http://www.epa.gov/dockets.

2. Summary of Petitioned-for Tolerance

   In the Federal Register of October 25, 2013 (78 FR 63938) (FRL-

   9901-96), EPA issued a document pursuant to FFDCA section 408(d)(3), 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 3F8196) by K-I Chemical U.S.A. Inc. c/o Landis International, Inc., P.O. Box 5126, Valdosta, GA 31603-5126. The petition requested that 40 CFR 180.659 be amended by increasing the tolerance for residues of the herbicide, pyroxasulfone, 3-5-(difluoromethoxy)-1-methyl-3-

   (trifluoromethyl)-1H-pyrazol-4-ylmethylsulfonyl-4,5-dihydro-5,5-

   dimethylisoxazole and its metabolite 5-difluoromethoxy-1-methyl-3-

   trifluoromethyl-1 H-pyrazol-4-carboxylic acid (M3) calculated as the stoichiometric equivalent of pyroxasulfone, in or on corn, field, grain from 0.015 to 0.02 parts per million (ppm); and also increasing the tolerance for residues of pyroxasulfone, 3-5-(difluoromethoxy)-1-

   methyl-3-(trifluoromethyl)-1H-pyrazol-4-ylmethylsulfonyl-4,5-

   dihydro-5,5-dimethylisoxazole and its metabolites 5-difluoromethoxy-1-

   methyl-3-trifluoromethyl-1 H-pyrazol-4-ylmethanesulfonic acid (M1), 5-

   difluoromethoxy-1-methyl-3-trifluoromethyl-1 H-pyrazol-4-carboxylic acid (M3), and 5-difluoromethoxy-3-trifluoromethyl-1 H-pyrazol-4-yl) methanesulfonic acid (M25) calculated as the stoichiometric equivalent of pyroxasulfone in or on corn, field, forage from 0.06 to 0.09 ppm. The amended tolerances were sought to cover residues that may be found on corn following use of pyroxasulfone with an adjuvant. That document referenced a summary of the petition prepared by K-I Chemical U.S.A. Inc. c/o Landis International, Inc., the registrant, which is available in the docket, http://www.regulations.gov. There were no comments received in response to the notice of filing.

3. Aggregate Risk Assessment and Determination of Safety

   Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a tolerance (the legal limit for a pesticide chemical residue in or on a food) only if EPA determines that the tolerance is ``safe.'' Section 408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical residue, including all anticipated dietary exposures and all other exposures for which there is reliable information.'' This includes exposure through drinking water and in residential settings, but does not include occupational exposure. Section 408(b)(2)(C) of FFDCA requires EPA to give special consideration to exposure of infants and children to the pesticide chemical residue in establishing a tolerance and to ``ensure that there is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue. . . .''

   Consistent with FFDCA section 408(b)(2)(D), and the factors specified in FFDCA section 408(b)(2)(D), EPA has reviewed the available scientific data and other relevant information in support of this action. EPA has sufficient data to assess the hazards of and to make a determination on aggregate exposure for pyroxasulfone, including exposure resulting from the tolerances established by this action. EPA's assessment of exposures and risks associated with pyroxasulfone follows.

   1. Toxicological Profile

      In the Federal Register of July 31, 2013 (78 FR 46274) (FRL-9393-

      6), EPA published a final rule (2013 rulemaking) establishing certain tolerances for residues of the herbicide pyroxasulfone and its metabolites based on EPA's conclusion that aggregate exposure to pyroxasulfone is safe for the general population, including infants and children. Since the 2013 rulemaking, there have been no additional tolerance actions for pyroxasulfone, nor has the toxicity profile for pyroxasulfone changed. Specific information on the studies reviewed for that rulemaking and the nature of the adverse effects caused by pyroxasulfone, as well as the no-observed-adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-level (LOAEL) from the toxicity studies are discussed in the 2013 rulemaking which can be found in docket ID number EPA-HQ-OPP-2012-0439.

   2. Toxicological Points of Departure/Levels of Concern

      Once a pesticide's toxicological profile is determined, EPA identifies toxicological points of departure (POD) and levels of concern to use in evaluating the risk posed by human exposure to the pesticide. For hazards that have a threshold below which there is no appreciable risk, the toxicological POD is used as the basis for derivation of reference values for risk assessment. PODs are developed based on a careful analysis of the doses in each toxicological study to determine the dose at which no adverse effects are observed (the NOAEL) and the lowest dose at which adverse effects of concern are identified (the LOAEL). Uncertainty/safety factors are used in conjunction with the POD to calculate a safe exposure level--generally referred to as a population-adjusted dose (PAD) or a reference dose (RfD)--and a safe margin of exposure (MOE). For non-threshold risks, the Agency assumes that any amount of exposure will lead to some degree of risk. Thus, the Agency estimates risk in terms of the probability of an occurrence of the adverse effect expected in a lifetime. For more information on the general principles EPA uses in risk characterization and a complete description of the risk assessment process, see http://www.epa.gov/pesticides/factsheets/riskassess.htm. A summary of the toxicological endpoints for pyroxasulfone used for human risk assessment is also discussed in Unit III.B of the final rule published in the Federal Register of February 29, 2012 (77 FR 12207) (FRL-9334-2).

   3. Exposure Assessment

      1. Dietary exposure from food and feed uses. In evaluating dietary exposure to pyroxasulfone, EPA conducted a new dietary exposure and risk assessment that considered exposure under the petitioned-for tolerances as well as all existing pyroxasulfone tolerances in 40 CFR 180.659. EPA assessed dietary exposures from pyroxasulfone in food as follows:

         i. Acute exposure. Quantitative acute dietary exposure and risk assessments are performed for a food-use pesticide, if a toxicological study has indicated the possibility of an effect of concern occurring as a result of a 1-day or single exposure. Such effects were identified for pyroxasulfone. In estimating acute dietary exposure, EPA used food consumption information from the United States Department of Agriculture's (USDA) National Health and Nutrition Examination Survey, What We Eat in America, (NHANES/WWEIA). As to residue levels in food, EPA assumed 100 percent crop treated (PCT) at tolerance-level residues adjusted upward to account for metabolites which are not in the

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         tolerance expression from specific use patterns.

         ii. Chronic exposure. In conducting the chronic dietary exposure assessment EPA used the food consumption data from the USDA/NHANES/

         WWEIA. As to residue levels in food, EPA made the same assumptions (adjusted tolerance-level residues and 100 PCT) as in the acute dietary exposure assessment.

         iii. Cancer. EPA determines whether quantitative cancer exposure and risk assessments are appropriate for a food-use pesticide based on the weight of the evidence from cancer studies and other relevant data. Cancer risk is quantified using a linear or nonlinear approach. If sufficient information on the carcinogenic mode of action is available, a threshold or nonlinear approach is used and a cancer RfD is calculated based on an earlier noncancer key event. If carcinogenic mode of action data are not available, or if the mode of action data determines a mutagenic mode of action, a default linear cancer slope factor approach is utilized. EPA has concluded that a nonlinear RfD approach is appropriate for assessing cancer risk to pyroxasulfone. Cancer risk was assessed using the same exposure estimates as discussed in Unit III.C.1.ii.

         iv. Anticipated residue and percent crop treated (PCT) information. EPA did not use anticipated residue and/or PCT information in the dietary assessment for pyroxasulfone. Adjusted tolerance level residues and/or 100 PCT were assumed for all food commodities.

      2. Dietary exposure from drinking water. The Agency used screening level water exposure models in the dietary exposure analysis and risk assessment for pyroxasulfone in drinking water. These simulation models take into account data on the physical, chemical, and fate/transport characteristics of pyroxasulfone. Further information regarding EPA drinking water models used in pesticide exposure assessment can be found at http://www.epa.gov/oppefed1/models/water/index.htm.

         Based on the Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS) and Pesticide Root Zone Model Ground Water (PRZM GW), the estimated drinking water concentrations (EDWCs) of pyroxasulfone for acute exposures are estimated to be 17 parts per billion (ppb) for surface water and 210 ppb for ground water. EDWCs of pyroxasulfone for chronic exposures for non-cancer assessments are estimated to be 3.2 ppb for surface water and 174 ppb for ground water.

         Modeled estimates of drinking water concentrations were directly entered into the dietary exposure model. For acute dietary risk assessment, the water concentration value of 210 ppb was used to assess the contribution to drinking water. For chronic dietary risk assessment, the water concentration of value 174 ppb was used to assess the contribution to drinking water.

      3. From non-dietary exposure. The term ``residential exposure'' is used in this document to refer to non-occupational, non-dietary exposure (e.g., for lawn and garden pest control, indoor pest control, termiticides, and flea and tick control on pets). Pyroxasulfone is not registered for any specific use patterns that would result in residential exposure.

      4. Cumulative effects from substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) of FFDCA 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.'' EPA has not found pyroxasulfone to share a common mechanism of toxicity with any other substances, and pyroxasulfone does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that pyroxasulfone does not have a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see EPA's Web site at http://www.epa.gov/pesticides/cumulative.

   4. Safety Factor for Infants and Children

      1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA shall apply an additional tenfold (10X) margin of safety for infants and children in the case of threshold effects to account for prenatal and postnatal toxicity and the completeness of the database on toxicity and exposure unless EPA determines based on reliable data that a different margin of safety will be safe for infants and children. This additional margin of safety is commonly referred to as the Food Quality Protection Act (FQPA) Safety Factor (SF). In applying this provision, EPA either retains the default value of 10X, or uses a different additional safety factor when reliable data available to EPA support the choice of a different factor.

      2. Prenatal and postnatal sensitivity. The prenatal and postnatal toxicity database for pyroxasulfone includes developmental toxicity studies in rats and rabbits, a DNT study in rats, and a 2-generation reproduction toxicity study in rats. As discussed in the 2013 rulemaking, evidence of increased susceptibility of fetuses and offspring was seen in the DNT study and developmental toxicity study in rabbits following in utero or post-natal exposure to pyroxasulfone. No increased susceptibility was seen in the rat developmental or reproduction toxicity studies. In rabbits, developmental toxicity was only seen at the limit dose of 1,000 milligrams/kilogram/day (mg/kg/

         day) as reduced fetal weight and increased fetal resorptions with a NOAEL of 500 mg/kg/day for these effects, compared to no maternal toxicity at these doses. In a DNT study in rats, offspring toxicity (decreased brain weight and morphometric changes on PND 21) was seen at 300 mg/kg/day compared to no maternal toxicity at 900 mg/kg/day. The degree of concern for the increased susceptibility seen in these studies is low and there are no residual uncertainties based on the following considerations:

         i. The increased susceptibility is occurring at high doses.

         ii. NOAELs and LOAELs have been identified for all effects of concern, and thus a clear dose response has been well defined.

         iii. The PODs selected for risk assessment are protective of the fetal/offspring effects.

      3. Conclusion. EPA has determined that reliable data show the safety of infants and children would be adequately protected if the FQPA SF were reduced to 1X. That decision is based on the following findings:

         i. The toxicity database for pyroxasulfone is complete.

         ii. Pyroxasulfone is a neurotoxic chemical and there is evidence of increased susceptibility of offspring with regard to neurotoxic effects in the rat DNT study. There is also evidence of increased susceptibility of fetuses/offspring with regard to non-neurotoxic effects in the rabbit developmental toxicity study. However, concern for the increased susceptibility is low for the reasons stated in Unit III.D.2.; therefore, EPA determined that a 10X FQPA SF is not necessary to protect infants and children.

         iii. There are no residual uncertainties identified in the exposure databases. The dietary food exposure assessments were performed based on 100 PCT and adjusted tolerance-level residues. EPA made conservative (protective) assumptions in the ground and surface

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         water modeling used to assess exposure to pyroxasulfone in drinking water. These assessments will not underestimate the exposure and risks posed by pyroxasulfone.

   5. Aggregate Risks and Determination of Safety

      EPA determines whether acute and chronic dietary pesticide exposures are safe by comparing aggregate exposure estimates to the acute PAD (aPAD) and chronic PAD (cPAD). For linear cancer risks, EPA calculates the lifetime probability of acquiring cancer given the estimated aggregate exposure. Short-, intermediate-, and chronic-term risks are evaluated by comparing the estimated aggregate food, water, and residential exposure to the appropriate PODs to ensure that an adequate MOE exists.

      1. Acute risk. Using the exposure assumptions discussed in this unit for acute exposure, the acute dietary exposure from food and water to pyroxasulfone will occupy 3.6% of the aPAD for all infants (