Pesticide Tolerances:
Federal Register: April 6, 2011 (Volume 76, Number 66)
Rules and Regulations
Page 18895-18899
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DOCID:fr06ap11-9
Page 18895
ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 180
EPA-HQ-OPP-2009-0325; FRL-8868-6
Hexythiazox; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
SUMMARY: This regulation establishes tolerances for residues of hexythiazox in or on corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; bean, dried; and bean, succulent. Gowan Company requested these tolerances under the Federal Food, Drug, and Cosmetic
Act (FFDCA).
DATES: This regulation is effective April 6, 2011. Objections and requests for hearings must be received on or before June 6, 2011, 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: 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.
FOR FURTHER INFORMATION CONTACT: 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.
SUPPLEMENTARY INFORMATION:
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General Information
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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.
Potentially affected entities may include, but are not limited to those engaged in the following activities:
Crop production (NAICS code 111).
Animal production (NAICS code 112).
Food manufacturing (NAICS code 311).
Pesticide manufacturing (NAICS code 32532).
This listing is not intended to be exhaustive, but rather to provide a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. The North American Industrial Classification System
(NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed under FOR FURTHER
INFORMATION CONTACT.
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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 eCFR site at http://www.gpoaccess.gov/ecfr. To access the harmonized test guidelines referenced in this document electronically, please go http://www.epa.gov/ocspp and select ``Test
Methods and Guidelines.''
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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-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
June 6, 2011. 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:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments.
Mail: Office of Pesticide Programs (OPP) Regulatory Public
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460-0001.
Delivery: OPP Regulatory Public Docket (7502P),
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South
Bldg.), 2777 S. Crystal Dr., Arlington, VA. Deliveries are only accepted during the Docket Facility's normal hours of operation (8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays).
Special arrangements should be made for deliveries of boxed information. The Docket Facility telephone number is (703) 305-5805.
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Summary of Petitioned For Tolerance
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 9F7549) by Gowan Company, 370 South Main Street, Yuma, AZ, 85364. The petition requested that 40 CFR 180.448 be amended by establishing 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 (expressed as parts per million of the parent compound), in or on corn, sweet, kernel plus cob with husk removed at 0.1 parts per million (ppm); corn, sweet, forage at 3 ppm; bean, dried at 0.4 ppm; and bean, succulent at 0.4 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 has revised the proposed tolerance levels for corn, sweet, forage; and bean, succulent to 4 ppm and 0.3 ppm, respectively. The
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reasons for these changes are explained in Unit IV.C.
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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 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.
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Toxicological Profile
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 low 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 at http:// www.regulations.gov in document ``Hexythiazox. Human Health Risk
Assessment to Support New Uses on Sweet Corn, Dry Beans and Succulent
Beans,'' page 24 in docket ID number EPA-HQ-OPP-2009-0325.
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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 hexythiazox used for human risk assessment can be found in the final rule published in the
Federal Register of March 17, 2010 (Vol. 75 FR 12691) (FRL-8813-7), and at http://www.regulations.gov in document ``Hexythiazox. Human Health
Risk Assessment to Support New Uses on Sweet Corn, Dry Beans and
Succulent Beans,'' page 11 in docket ID number EPA-HQ-OPP-2009-0325.
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Exposure Assessment 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: 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. 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 USDA 1994-1996 and 1998 Nationwide Continuing Surveys of Food Intake by Individuals
(CSFII). As to residue levels in food, EPA used tolerance level residues, assumed 100 percent crop treated (PCT), and incorporated DEEM default processing factors. 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. Based on the data in the Federal Register of March 17, 2010 (Vol. 75 FR 12691) (FRL-8813-7), EPA has concluded that a nonlinear RfD approach is appropriate for assessing cancer risk to hexythiazox. Cancer risk was assessed using the same exposure estimates as discussed in Unit III.C.1.ii., chronic exposure. iv. Anticipated residue and percent crop treated (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
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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 4.5 ppb for surface water. Since surface water residue values greatly exceed groundwater EDWCs, surface water residues were used in the dietary risk assessment.
Modeled estimates of drinking water concentrations were directly entered into the dietary exposure model. 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).
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, ornamental landscape plantings, ornamental plants, trees and vines in nurseries, residential fruit trees, nut trees, 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 July 14, 2010
(75 FR 40741), and at http://www.regulations.gov in document
``Hexythiazox. Human Health Risk Assessment to Support New Uses on
Sweet Corn, Dry Beans, and Succulent Beans,'' page 16 in docket ID number EPA-HQ-OPP-2009-0325.
Further information regarding EPA standard assumptions and generic inputs for residential exposures may be found at http://www.epa.gov/ pesticides/trac/science/trac6a05.pdf. 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 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 Web site at http:// www.epa.gov/pesticides/cumulative.
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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 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 toxicology data base indicates no increased susceptibility of rats or rabbits to in utero and/or postnatal exposure to hexythiazox. 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 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. EPA used similarly conservative assumptions to assess postapplication exposure of children as well as incidental oral exposure of toddlers.
These assessments will not underestimate the exposure and risks posed by hexythiazox.
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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. An acute aggregate risk assessment takes into account acute exposure estimates from dietary consumption of food and drinking water. No adverse effect resulting from
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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 51% of the cPAD for children 1-2 years of age, 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. 3. Short-term risk. Short-term aggregate exposure takes into account short-term residential exposure plus chronic exposure to food and water (considered to be a background exposure level).
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 15,000 for adults and 1,900 for children. Because EPA's level of concern for hexythiazox is a MOE of 100 or below, these MOEs are not of concern. 4. Intermediate-term risk. Intermediate-term aggregate exposure takes into account intermediate-term residential exposure plus chronic exposure to food and water (considered to be a background exposure level).
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 exposures 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 15,000 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.C.1.iii, 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.
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Other Considerations
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Analytical Enforcement Methodology
Adequate enforcement methodology (high performance liquid chromatography method with UV 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.
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International Residue Limits
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 U.N. 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 United
States 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.
A Codex MRL for common beans (pods and/or immature seeds) is currently established at 0.5 ppm. It is not possible to harmonize the
U.S. tolerance with the Codex MRL since the Codex MRL is for parent compound only and the U.S. expression includes metabolites of concern.
There are no Canadian or Mexican MRLs for beans and there is no Codex,
Canadian or Mexican MRL for sweet corn commodities.
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Revisions to Petitioned for Tolerances
Based upon review of the data supporting the petition, EPA has revised the proposed tolerance levels for corn, sweet, forage; and bean, succulent to 4 ppm and 0.3 ppm, respectively. The tolerance spreadsheet in the Agency's Guidance for Setting Pesticide Tolerances
Based on Field Trial Data was used to determine appropriate tolerance levels for sweet corn forage, dried beans and succulent beans. The tolerance spreadsheet was not used for sweet corn kernel plus cob with husk removed (K+CWHR) because >65% of the residues were
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