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美国修订精异丙甲草胺限量要求(S-metolachlor; Pesticide Tolerances)

嘉峪检测网        2015-09-26 18:39

【发布单位】 EPA
【发布文号】
【发布日期】 2015-7-8
【生效日期】 2015-7-8
【废止日期】
【替代法规】
【效  力】
【食品伙伴网解读】 2015年7月8日,美国EPA发布一条最终条例,修订在莴苣等多种蔬菜内部或表面精异丙甲草胺的残留限量要求。本规则于2015年7月8日起生效,反对或听证要求按40 CFR§178的说明在2015年9月8日前提交。部分商品的残留限量规定如下:精异丙甲草胺在莴苣中的残留限量为1.50ppm;在除了蔓越橘外的低成长浆果亚组13-07G的残留限量为0.40ppm;在葵花子组20B中的残留限量为1.00ppm;在瓜类蔬菜组9中的残留限量为0.50ppm;在除了塔巴斯科辣椒外的果类蔬菜8-10组中的残留限量为0.10ppm。此外,在§180.368部分,删除对黄瓜、甜瓜子群9A、秋葵、南瓜、冬天、向日葵种子和除了塔巴斯科辣椒的蔬菜的限量要求相关条款。
  ACTION
 
  Final Rule.
 
  SUMMARY
 
  This regulation establishes tolerances for residues of S-metolachlor in or on multiple commodities which are identified and discussed later in this document. Interregional Research Project Number 4 (IR-4) requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA).
 
  TABLE OF CONTENTS
 
  Back to Top
 
  DATES:
 
  ADDRESSES:
 
  FOR FURTHER INFORMATION CONTACT:
 
  SUPPLEMENTARY INFORMATION:
 
  I. General Information
 
  A. Does this action apply to me?
 
  B. How can I get electronic access to other related information?
 
  C. How can I file an objection or hearing request?
 
  II. Summary of Petitioned-For Tolerance
 
  III. Aggregate Risk Assessment and Determination of Safety
 
  A. Toxicological Profile
 
  B. Toxicological Points of Departure/Levels of Concern
 
  C. Exposure Assessment
 
  D. Safety Factor for Infants and Children
 
  E. Aggregate Risks and Determination of Safety
 
  IV. Other Considerations
 
  A. Analytical Enforcement Methodology
 
  B. International Residue Limits
 
  C. Revisions to Petitioned-For Tolerances
 
  V. Conclusion
 
  VI. Statutory and Executive Order Reviews
 
  VII. Congressional Review Act
 
  List of Subjects in 40 CFR Part 180
 
  PART 180—[AMENDED]
 
  TABLES
 
  Back to Top
 
  Table 1—Summary of Toxicological Doses and Endpoints for S-metolachlor for Use in Human Health Risk Assessment
 
  DATES:
 
  Back to Top
 
  This regulation is effective July 8, 2015. Objections and requests for hearings must be received on or before September 8, 2015, 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:
 
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  The docket for this action, identified by docket identification (ID) number EPA-HQ-OPP-2014-0284, 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:
 
  Back to Top
 
  Susan Lewis, 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:
 
  Back to Top
 
  I. General Information
 
  Back to Top
 
  A. 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).
 
  B. 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.
 
  C. 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-2014-0284 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 8, 2015. 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-2014-0284, 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.
 
  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.
 
  II. Summary of Petitioned-For Tolerance
 
  Back to Top
 
  In the Federal Register of December 17, 2014 (79 FR 75107) (FRL-9918-90), 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 4E8248) by IR-4 500 College Road East, Suite 201 W, Princeton, NJ 08540, requests to establish a tolerance in 40 CFR part 180 for residues of S-metolachlor in or on the raw agricultural commodity lettuce at 1.5 parts per million (ppm); vegetable, cucurbit group 9 at 0.50 ppm; vegetable, fruiting, group 8-10, except tabasco pepper at 0.10 ppm; low growing berry subgroup 13-07G except cranberry at 0.40 ppm; and sunflower subgroup 20B at 0.50 ppm and the concurrent deletion of the existing tolerances for okra; vegetable, fruiting, group 8 except tabasco pepper; cucumber; melon subgroup 9A; pumpkin; squash, winter; and sunflower, seed. That document referenced a summary of the petition prepared by Syngenta Crop Protection, 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 modified the levels at which some of the tolerances are being established. The reason for these changes are explained in Unit IV.C.
 
  III. Aggregate Risk Assessment and Determination of Safety
 
  Back to Top
 
  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 exposureof 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 S-metolachlor including exposure resulting from the tolerances established by this action. EPA's assessment of exposures and risks associated with S-metolachlor follows.
 
  A. 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.
 
  The existing toxicological database is primarily comprised of studies conducted with metolachlor. However, bridging studies indicate that the metolachlor toxicology database can be used to assess toxicity for S-metolachlor. In subchronic (metolachlor and S-metolachlor) and chronic (metolachlor) toxicity studies in dogs and rats decreased body weight and body weight (bw) gain were the most commonly observed effects. No systemic toxicity was observed in rabbits when metolachlor was administered dermally. There was no evidence of neurotoxic effects in the available toxicity studies, and there is no evidence of Immunotoxicity in the submitted mouse Immunotoxicity study.
 
  Prenatal developmental studies in the rat and rabbit with both metolachlor and S-metolachlor revealed no evidence of a qualitative or quantitative susceptibility in fetal animals. A 2-generation reproduction study with metolachlor in rats showed no evidence of parental or reproductive toxicity. There are no residual uncertainties with regard to pre- and/or postnatal toxicity.
 
  Metolachlor has been evaluated for carcinogenic effects in the mouse and the rat. Metolachlor did not cause an increase in tumors of any kind in mice. In rats, metolachlor caused an increase in benign liver tumors in rats, but this increase was seen only at the highest dose tested and was statistically significant compared to controls only in females. There was no evidence of mutagenic or cytogenetic effects in vivo or in vitro. Based on this evidence, EPA has concluded that metolachlor does not have a common mechanism of carcinogenicity with acetochlor and alachlor, compounds that are structurally similar to metolachlor. Metolachlor has been classified as a Group C, possible human carcinogen, based on liver tumors in rats at the highest dose tested (HDT).
 
  Taking into account the qualitatively weak evidence on carcinogenic effects and the fact that the increase in benign tumors in female rats occurs at a dose 1,500 times the chronic reference dose (cRfD), EPA has concluded that the cRfD is protective of any potential cancer effect.
 
  Specific information on the studies received and the nature of the adverse effects caused by S-metolachlor 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 the document “S-metolachlor—Risk Assessment for Establishment of Tolerances for New Uses on Lettuce, Low Growing Berry Subgroup 13-07G, except Cranberry; Vegetable, Cucurbit, Group 9; Sunflower subgroup 20B; Vegetable, Fruiting, Group 8-10; except Tabasco Pepper and Okra” on pp. 40 in docket ID number EPA-HQ-OPP-2014-0284.
 
  B. 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 the NOAEL and the LOAEL are identified. 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 S-metolachlor used for human risk assessment is shown in Table 1 of this unit.
 
  Table 1—Summary of Toxicological Doses and Endpoints for S-metolachlor for Use in Human Health Risk Assessment Back to Top
 
  Exposure/scenarioPoint of departure and uncertainty/safety factorsRfD, PAD, LOC for risk assessmentStudy and toxicological effects
 
  FQPA SF = Food Quality Protection Act Safety Factor. LOAEL = lowest-observed-adverse-effect-level. LOC = level of concern. Mg/kg/day = milligram/kilogram/day. MOE = margin of exposure. NOAEL = no-observed-adverse-effect-level. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose. UF = uncertainty factor. UF A= extrapolation from animal to human (interspecies). UF DB= to account for the absence of data or other data deficiency. UF H= potential variation in sensitivity among members of the human population (intraspecies).
 
  Acute dietary (General population including infants and children)NOAEL = 300 mg/kg/dayAcute RfD = 3.0 mg/kg/dayDevelopmental Toxicity Study—Rat (metolachlor).
 
  UF A= 10x UF H= 10x FQPA SF = 1x.aPAD = 3.0 mg/kg/dayLOAEL = 1,000 mg/kg/day based increased incidence of death, clinical signs (clonic and/or tonic convulsions, excessive salivation, urine-stained abdominal fur and/or excessive lacrimation), and decreased body weight gain.
 
  Chronic dietary (All populations)NOAEL= 9.7 mg/kg/dayChronic RfD = 0.097 mg/kg/dayOne Year Chronic Toxicity—Dog (metolachlor).
 
  UF A= 10x UF H= 10x FQPA SF = 1x.cPAD = 0.097 mg/kg/dayLOAEL = 33 mg/kg/day based decreased body weight gain in females.
 
  Incidental oral short-term (1 to 30 days)NOAEL= 50 mg/kg/dayLOC for MOE = 100Developmental Toxicity Study—Rat (S-metolachlor).
 
  UF A= 10x UF H= 10x FQPA SF = 1x.LOAEL = 500 mg/kg/day based on increased incidence of clinical signs, decreased body weight/body weight gain, food consumption and food efficiency seen in maternal animals.
 
  Inhalation short-term (1 to 30 days)Inhalation (or oral) study NOAEL= 50 mg/kg/day (inhalation absorption rate = 100%)LOC for MOE = 1,000Developmental Toxicity Study—Rat (S-metolachlor).
 
  UF A= 10x UF H= 10x FQPA SF = 10x UF DB.LOAEL = 500 mg/kg/day based on increased incidence of clinical signs, decreased body weight/body weight gain, food consumption and food efficiency seen at the LOAEL in maternal animals.
 
  Cancer (all routes)Metolachlor has been classified as a Group C carcinogen with risk quantitated using a non-linear RfD approach.
 
  C. Exposure Assessment
 
  1. Dietary exposure from food and feed uses. In evaluating dietary exposure to S-metolachlor, EPA considered exposure under the petitioned-for tolerances as well as all existing S-metolachlor tolerances in 40 CFR 180.368. EPA assessed dietary exposures from S-metolachlor 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 S-metolachlor. 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 tolerance level residues and 100 percent crop treated (PCT).
 
  ii. Chronic exposure. In conducting the chronic dietary exposure assessment EPA used the food consumption data from the USDA's NHANES/WWEIA. As to residue levels in food, EPA assumed tolerance level residues and 100 PCT.
 
  iii. Cancer. Based on the data summarized in Unit III.A., EPA has concluded that a nonlinear RfD approach is appropriate for assessing cancer risk to S-metolachlor. Therefore, a separate quantitative cancer exposure assessment is unnecessary since the chronic dietary risk estimate will be protective of potential cancer risk.
 
  iv. Anticipated residue and PCT information. EPA did not use anticipated residue or PCT information in the dietary assessment for S-metolachlor. Tolerance level residues and 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 S-metolachlor in drinking water. These simulation models take into account data on the physical, chemical, and fate/transport characteristics of S-metolachlor. 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.
 
  The Agency assessed parent metolachlor, and the metabolites CGA-51202 (metolachlor-OA), CGA-40172, and CGA-50720 together in the drinking water assessment using a total toxic residues (TTR) approach where half-lives were recalculated to collectively account for the parent and the combined residues of concern.
 
  Based on the Surface Water Concentration Calculator (SWCC), the Pesticide Root Zone Model Ground Water (PRZM GW), and the Screening Concentration in Ground Water (SCI-GROW), the estimated drinking water concentrations (EDWCs) of S-metolachlor and its metabolites for acute exposures are estimated to be 371 parts per billion (ppb) for surface water and 1,060 ppb for ground water, and for chronic exposures are estimated to be 43.70 ppb for surface water and 14.3 ppb in 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 1,060 ppb was used to assess the contribution to drinking water. For chronic dietary risk assessment, the water concentration of value 43.70 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, termiticide, and flea and tick control on pets).
 
  S-metolachlor is currently registered for the following uses that could result in residential exposures: On commercial (sod farm) and residential warm-season turf grasses and other non-crop land including golf courses, sports fields, and ornamental gardens. EPA assessed residential exposure using the following assumptions: For residential handlers, short-term inhalation exposure isexpected. The following scenarios were evaluated:
 
  Mixing/loading/applying gardens/trees with manually-pressurized hand wand, hose-end sprayer, backpack, and sprinkler can equipment.
 
  Mixing/loading/applying lawns/turf with manually-pressurized hand wand, hose-end sprayer, backpack, and sprinkler can equipment.
 
  For residential post-application, there is the potential for short-term incidental oral exposure for individuals exposed as a result of being in an environment that has been previously treated with S-metolachlor. The quantitative exposure/risk assessment for residential post-application exposures is based on the following scenario:
 
  Hand-to-mouth incidental oral exposure of children 1-2 years old playing on turf treated with S-metolachlor.
 
  Further information regarding EPA standard assumptions and generic inputs for residential exposures may be found at http://www.epa.gov/pesticides/science/residential-exposure-sop.html.
 
  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 S-metolachlor to share a common mechanism of toxicity with any other substances, and S-metolachlor does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that S-metolachlor 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.
 
  D. Safety Factor for Infants and Children
 
  1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA shall apply an additional tenfold (10×) 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 Safety Factor (FQPA SF). In applying this provision, EPA either retains the default value of 10×, 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. There was no evidence of increased quantitative or qualitative fetal susceptibility in the prenatal developmental studies in rats and rabbits or in the reproductive toxicity study in rats, with either metolachlor or S-metolachlor. In general, significant developmental toxicity was not seen in rats or rabbits with either compound. The only effects observed in fetal animals were in the rat prenatal developmental study and included slightly decreased number of implantations per dam, decreased number of live fetuses/dam, increased number of resorptions/dam and significant decrease in mean fetal bw. These effects occurred at maternally toxic doses (1,000 milligram/kilogram/day (mg/kg/day)).
 
  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 1× for all scenarios except inhalation. For inhalation scenarios a 10× database uncertainty factor (UF) still applies. This decision is based on the following findings:
 
  i. The toxicology database for metolachlor and S-metolachlor is complete, with the exception of a required subchronic inhalation study for metolachlor. As noted above, a 10× data base UF will be applied only for assessing risk for inhalation exposure scenarios.
 
  ii. There is no indication that S-metolachlor 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 S-metolachlor 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. EPA made conservative (protective) assumptions in the ground and surface water modeling used to assess exposure to S-metolachlor in drinking water. EPA used similarly conservative assumptions to assess post-application incidental oral exposure of children 1<2 years old. These assessments will not underestimate the exposure and risks posed by S-metolachlor.
 
  E. 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 S-metolachlor will occupy 6.1% of the aPAD for all infants (less than 1 year old), the population group receiving the greatest exposure.
 
  2. Chronic risk. Using the exposure assumptions described in this unit for chronic exposure, EPA has concluded that chronic exposure to S-metolachlor from food and water will utilize 6.8% 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 S-metolachlor 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).
 
  S-metolachlor is currently registered for uses that could result in short-term residential exposure, and the Agency has determined that it is appropriate to aggregate chronic exposure through food and water with short-term residential exposures to S-metolachlor. Potential short-term residential risk scenarios anticipated include adult inhalation handler exposure to turf via backpack sprayer and post-application incidental oral exposure of children playing on treated lawns.
 
  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 10,400 for adults and 1,100 for children 1-2 years old. Because EPA's levels of concern for S-metolachlor is aMOE of 1,000 or below for inhalation scenarios (adults) and 100 or below for incidental oral scenarios (children 1-2 years old), 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).
 
  An intermediate-term adverse effect was identified; however, S-metolachlor is not registered for any use patterns that would result in intermediate-term residential exposure. Because there is no intermediate-term residential exposure and chronic dietary exposure has already been assessed under the appropriately protective cPAD (which is at least as protective as the POD used to assess intermediate-term risk), no further assessment of intermediate-term risk is necessary, and EPA relies on the chronic dietary risk assessment for evaluating intermediate-term risk for S-metolachlor.
 
  5. Aggregate cancer risk for U.S. population. As discussed in Unit III.A, the chronic dietary risk assessment is protective of any potential cancer effects. Based on the results of that assessment, EPA concludes that S-metolachlor is not expected to pose a cancer risk to humans.
 
  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 S-metolachlor residues.
 
  IV. Other Considerations
 
  Back to Top
 
  A. Analytical Enforcement Methodology
 
  Adequate methodology is available for enforcing the established and recommended tolerances. PAM Vol. II, Pesticide Regulation Section 180.368, lists a gas chromatography with nitrogen-phosphorus detector (GC/NPD) method (Method I) for determining residues in/on plant commodities and a gas chromatography with mass selective detector (GC/MSD) method (Method II) for determining residues in livestock commodities. These methods determine residues of metolachlor and its metabolites as either CGA-37913 or CGA-49751 following acid hydrolysis. Adequate data are also available on the recovery of metolachlor through FDA's Multiresidue Method Testing Protocols which indicate that metolachlor is completely recovered through Method 302.
 
  B. 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 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 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.
 
  The Codex has not established a MRL for S-metolachlor.
 
  C. Revisions to Petitioned-For Tolerances
 
  The tolerance being established for the sunflower subgroup 20B is 1.0 ppm, not 0.50 ppm as proposed. This is due to the Agency using the Organization for Economic Cooperation and Development (OECD) Tolerance Calculation procedures, which determined that a tolerance of 1.0 ppm is appropriate based on entry of the 4 field trials for pre-emergence application.
 
  V. Conclusion
 
  Back to Top
 
  Therefore, tolerances are established for residues of S-metolachlor in or on lettuce at 1.5 ppm; the low growing berry subgroup 13-07G, except cranberry at 0.40 ppm; the sunflower subgroup 20B at 1.0 ppm; the vegetable, cucurbit group 9 at 0.50 ppm; and the vegetable, fruiting, group 8-10, except tabasco pepper at 0.10 ppm. Additionally, due to the establishment of the tolerances listed above, the existing tolerances for vegetable, fruiting, group 8, except tabasco pepper; cucumber; melon subgroup 9A; okra; pumpkin; squash, winter; and sunflower, seed are removed as they are unnecessary.
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来源:美国联邦公报

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