Source: https://www.federalregister.gov/documents/2010/07/14/2010-17034/hexythiazox-pesticide-tolerances
Timestamp: 2018-03-17 05:43:08
Document Index: 699697933

Matched Legal Cases: ['art 178', 'art 178', 'art 178', 'art 2', 'art 158', 'art 158', '§\u2009180']

Federal Register :: Hexythiazox; Pesticide Tolerances
A Rule by the Environmental Protection Agency on 07/14/2010
This regulation is effective July 14, 2010. Objections and requests for hearings must be received on or before September 13, 2010, and must be filed in accordance with the instructions provided in 40 CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).
75 FR 40741
40741-40745 (5 pages)
EPA-HQ-OPP-2009-0325
FRL-8833-6
2010-17034
https://www.federalregister.gov/d/2010-17034 https://www.federalregister.gov/d/2010-17034
This regulation revises tolerances for combined residues of hexythiazox in or on stone fruit. Gowan Company requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA).
EPA has established a docket for this action under docket identification (ID) number EPA-HQ-OPP-2009-0325. All documents in the docket are listed in the docket index available at http://www.regulations.gov. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available in the electronic docket at http://www.regulations.gov, or, if only available in hard copy, at the OPP Regulatory Public Docket in Rm. S-4400, One Potomac Yard (South Bldg.), 2777 S. Crystal Dr., Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The Docket Facility telephone number is (703) 305-5805.
Olga Odiott, Registration Division (7505P), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (703) 308-9369; e-mail address: odiott.olga@epa.gov.
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 Start Printed Page 40742provided in 40 CFR part 178. To ensure proper receipt by EPA, you must identify docket ID number EPA-HQ-OPP-2009-0325 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 September 13, 2010. 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 that does not contain any 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 a copy of your non-CBI objection or hearing request, identified by docket ID number EPA-HQ-OPP-2009-0325, by one of the following methods:
In the Federal Register of August 19, 2009 (74 FR 41898) (FRL-8426-7), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 9F7556) by Gowan Company, 370 South Main Street, Yuma, AZ 85364. The petition requested that 40 CFR 180.448 be amended by revising tolerances for residues of the insecticide hexythiazox, (trans-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxothiazolidine-3-carboxamide) and its metabolites containing the (4-chlorophenyl)-4-methyl-2-oxo-3- thiazolidine moiety, as follows: Revising the tolerance “fruit, stone, group 12, except plums” to read “ fruit, stone, group 12; removing the existing separate tolerance for fresh, prune, plums at 0.1 parts per million (ppm); revising the tolerance in or on plum, prune, dried from 0.4 to 1.3 ppm; and by revising the tolerance in or on grapes from 0.75 to 1.0 ppm. That notice referenced a summary of the petition prepared by Gowan Company, the registrant, which is available in the docket, http://www.regulations.gov. There were no comments received in response to the notice of filing.
Based upon review of the data supporting the petition, EPA issued a notice in the Federal Register of March 17, 2010 (75 FR 12691) (FRL-8813-7), revising the tolerance for grapes and revising the tolerance expression for hexythiazox. In that notice the Agency also announced that the residue chemistry data were insufficient to support the proposed revisions of the tolerances for the stone fruit use. Gowan Company, the registrant, has submitted additional data to adequately support the requested revisions to the stone fruit tolerances. This action addresses the updated aggregate risk assessment incorporating the revised dietary assessment on stone fruit.
Consistent with section 408(b)(2)(D) of FFDCA, and the factors specified in section 408(b)(2)(D) of FFDCA, 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 hexythiazox including exposure resulting from the tolerances established by this action. EPA's assessment of exposures and risks associated with hexythiazox follows.
EPA has evaluated the available toxicity data and considered its validity, completeness, and reliability as well as the relationship of the results of the studies to human risk. EPA has also considered available information concerning the variability of the sensitivities of major identifiable subgroups of consumers, including infants and children. Hexythiazox has a low order of acute toxicity by the oral, dermal and inhalation routes of exposure. It produces mild eye irritation, is not a dermal irritant, and is negative for dermal sensitization. Hexythiazox is not a developmental or reproductive toxicant. The toxicology database for hexythiazox provides no indication of increased susceptibility in rats or rabbits from in utero and postnatal exposure to hexythiazox. The database does not show any evidence of treatment-related effects on the nervous system or the immune system. Hexythiazox is classified as “Likely to be Carcinogenic to Humans.” EPA has determined that a non-quantitative risk assessment approach (i.e., nonlinear, reference dose (RfD) approach) was appropriate and protective of all chronic effects including potential carcinogenicity of hexythiazox.
Specific information on the studies received and the nature of the adverse effects caused by hexythiazox as well as the no-observed-adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-level (LOAEL) from the toxicity studies can be found in the final rule published in the Federal Register of March 17, 2010 (75 FR 12691), and at http://www.regulations.gov in document “Hexythiazox. Human Health Risk Assessment to Support Amended Use on Stone Fruit Reducing the Preharvest Interval from 28-Days to 7-Days,” p. 28 in docket ID number EPA-HQ-OPP-2009-0325.
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 Start Printed Page 40743observed (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 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 hexythiazox used for human risk assessment can be found in the final rule published in the Federal Register of March 17, 2010 (75 FR 12691), and at http://www.regulations.gov in document “Hexythiazox. Human Health Risk Assessment to Support Amended Use on Stone Fruit Reducing the Preharvest Interval from 28-Days to 7-Days,” p. 13 in docket ID number EPA-HQ-OPP-2009-0325.
1. Dietary exposure from food and feed uses. In evaluating dietary exposure to hexythiazox, EPA considered exposure under the petitioned-for tolerances as well as all existing hexythiazox tolerances in 40 CFR 180.448. EPA assessed dietary exposures from hexythiazox in food as follows:
No such effects were identified in the toxicological studies for hexythiazox; therefore, a quantitative acute dietary exposure assessment is unnecessary.
ii. Chronic exposure. In conducting the chronic dietary exposure assessment EPA used the food consumption data from the United States Department of Agriculture (USDA) 1994-1996 and 1998 CSFII. As to residue levels in food, EPA used tolerance level residues, assumed 100 percent crop treated (PCT), and incorporated default processing factors.
iii. Cancer. As discussed in this unit, EPA has determined that the chronic RfD is sufficient to evaluate all chronic risks for this chemical, including carcinogenic potential. Cancer risk was quantified using the same estimates as discussed in Unit III.C.1.ii., chronic exposure.
iv. Anticipated residue and PCT information. EPA did not use anticipated residue and/or PCT information in the dietary assessment for hexythiazox. 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 hexythiazox in drinking water. These simulation models take into account data on the physical, chemical, and fate/transport characteristics of hexythiazox. 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) the estimated drinking water concentration (EDWC) of hexythiazox for chronic exposures for non-cancer and cancer assessments is estimated to be 4.1 parts per billion (ppb) for surface water. Since surface water residue values greatly exceed groundwater EDWCs, surface water residues were used in the dietary risk assessment.
The modeled estimate of drinking water concentrations was directly entered into the dietary exposure model.
Hexythiazox is not currently registered for any specific use patterns that would result in residential exposure. However, the following uses that could result in residential exposures are pending registration in the near future and are included in this risk assessment: Turf, gardens, ornamental landscape plantings, ornamental plants, trees and vines in nurseries, residential fruit trees, nut trees and caneberries, and orchids.
Both adults and children may be exposed to hexythiazox residues from contact with treated lawns or treated plants. The exposure and risk assessment included risks to adult handlers from inhalation exposures. The exposure assessment for children included risks from incidental oral exposure resulting from transfer of residues from the hands or objects to the mouth, and from incidental ingestion of soil. Details of the residential exposure and risk assessment are contained in the final rule published in the Federal Register of March 17, 2010 (75 FR 12691), and at http://www.regulations.gov in document “Hexythiazox. Human Health Risk Assessment to Support Amended Use on Stone Fruit Reducing the Preharvest Interval from 28-Days to 7-Days,” p. 19 in docket ID number EPA-HQ-OPP-2009-0325.
EPA has not found hexythiazox to share a common mechanism of toxicity with any other substances, and hexythiazox does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that hexythiazox 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 website at http://www.epa.gov/​pesticides/​cumulative.
2. Prenatal and postnatal sensitivity. The prenatal and postnatal toxicology data base indicates no increased Start Printed Page 40744susceptibility of rats or rabbits to in utero and/or postnatal exposure to hexythiazox.
i. The toxicity database for hexythiazox is incomplete under the new 40 CFR part 158 data requirements for conventional pesticides, which requires certain generic testing, including acute and subchronic neurotoxicity studies and an immunotoxicity study. However, the toxicology database does not show any evidence of treatment-related effects on the nervous system or the immune system. The overall weight of evidence suggests that this chemical does not directly target either system. Although acute and subchronic neurotoxicity studies and an immunotoxicity study are required as a part of new data requirements in the 40 CFR part 158 for conventional pesticide registrations, the Agency does not believe that conducting these studies will result in a lower POD than any currently used for risk assessment, and therefore, a database uncertainty factor (UFDB) is not needed to account for the lack of these studies.
ii. There is no indication that hexythiazox is a neurotoxic chemical and there is no need for a developmental neurotoxicity study or additional UFs to account for neurotoxicity.
iii. There is no evidence that hexythiazox results in increased susceptibility in in utero rats or rabbits in the prenatal developmental studies or in young rats in the 2-generation reproduction study.
iv. There are no residual uncertainties identified in the exposure databases. The dietary food exposure assessments were performed based on 100 PCT and tolerance-level residues. The dietary risk assessment is highly conservative and not expected to underestimate risk. EPA made conservative (protective) assumptions in the ground and surface water modeling used to assess exposure to hexythiazox in drinking water. These assessments will not underestimate the exposure and risks posed by hexythiazox.
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-term, intermediate-term, 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. An acute aggregate risk assessment takes into account acute exposure estimates from dietary consumption of food and drinking water. No adverse effect resulting from a single oral exposure was identified and no acute dietary endpoint was selected. Therefore, hexythiazox is not expected to pose an acute risk.
2. Chronic risk. Using the exposure assumptions described in this unit for chronic exposure, EPA has concluded that chronic exposure to hexythiazox from food and water will utilize 49% of the cPAD for (children 1-2 years old) the population group receiving the greatest exposure. Based on the explanation in Unit III.C.3., regarding residential use patterns, chronic residential exposure to residues of hexythiazox is not expected.
There are potential short-term exposures from the pending residential uses for hexythiazox. The Agency has determined that it is appropriate to aggregate chronic exposure through food and water with short-term residential exposures to hexythiazox.
Using the exposure assumptions described in this unit for short-term exposures, EPA has concluded the combined short-term food, water, and residential exposures result in aggregate MOEs of 16,000 for adults and 2,000 for children. Because EPA's level of concern for hexythiazox is a MOE of 100 or below, these MOEs are not of concern.
There are potential intermediate-term exposures from the pending residential uses for hexythiazox. The Agency has determined that it is appropriate to aggregate chronic exposure through food and water with intermediate-term residential exposure to hexythiazox.
Using the exposure assumptions described in this unit for intermediate-term exposures, EPA has concluded that the combined intermediate-term food, water, and residential exposures result in aggregate MOEs of 16,000 for adults and 2,200 for children. Because EPA's level of concern for hexythiazox is a MOE of 100 or below, these MOEs are not of concern.
5. Aggregate cancer risk for U.S. population. As discussed in Unit III.A., and the Federal Register of March 17, 2010, (75 FR 12691), EPA concluded that regulation based on the chronic reference dose will be protective for both chronic and carcinogenic risks. As noted in this unit there are no chronic risks of concern.
6. Determination of safety. Based on these risk assessments, EPA concludes that there is a reasonable certainty that no harm will result to the general population, or to infants and children from aggregate exposure to hexythiazox residues.
Adequate enforcement methodology (high performance liquid chromatography with ultra violet detection (HPLC/UV) is available to enforce the tolerance expression. The method may be requested from: Chief, Analytical Chemistry Branch, Environmental Science Center, 701 Mapes Rd., Ft. Meade, MD 20755-5350; telephone number: (410) 305-2905; e-mail address: residuemethods@epa.gov.
In making its tolerance decisions, EPA seeks to harmonize U.S. tolerances with international standards whenever possible, consistent with U.S. food safety standards and agricultural practices. EPA considers the international maximum residue limits (MRLs) established by the Codex Alimentarius Commission (Codex), as required by FFDCA section 408(b)(4). The Codex Alimentarius is a joint United Nations Food and Agriculture Organization/World Health Organization food standards program, and it is recognized as an international food safety standards-setting organization in trade agreements to which the U.S. is a party. EPA may establish a tolerance that is different from a Codex MRL; however, FFDCA section 408(b)(4) requires that EPA explain the reasons for departing from the Codex level.
Codex MRLs are established for residues of hexythiazox in or on cherry and peach at 1.0 ppm, and plum (including prune) at 0.2 ppm. There are no currently established Canadian or Mexican MRLs for residues of hexythiazox for these crops. The Agency Start Printed Page 40745has harmonized the residue level with established Codex MRLs on cherry and peach, but notes that it is not possible to harmonize the tolerance expression at this time as the Codex MRL includes parent only. Additionally, it is not possible to harmonize with the codex MRL for plums as the established Codex MRL of 0.2 ppm is too low to cover residues that could result from the use of hexythiazox in the U.S.
Therefore, the tolerance for residues of hexythiazox, in or on plum, prune, dried is revised from 0.4 ppm to 1.3 ppm; and the tolerance for fruit, stone, group 12, except plum is revised to read fruit, stone, group 12. The established tolerances for plum and for plum, prune, fresh can be removed as these commodities are addressed by the stone fruit group tolerance.
2. In § 180.448, the table in paragraph (a) is amended as follows:
i. Remove the entry for plum at 0.10 ppm and for plum, prune, fresh at 0.10 ppm;
ii. Revise the entry for Fruit, stone, group 12, except plum; and
iii. Revise the entry for plum, prune, dried.
Fruit, stone, group 12 1.0
Plum, prune, dried 1.3
[FR Doc. 2010-17034 Filed 7-13-10; 8:45 am]