Acetochlor; Pesticide Tolerances
Federal Register, Volume 79 Issue 14 (Wednesday, January 22, 2014)
Federal Register Volume 79, Number 14 (Wednesday, January 22, 2014)
Rules and Regulations
Pages 3512-3518
From the Federal Register Online via the Government Printing Office www.gpo.gov
FR Doc No: 2014-01183
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
EPA-HQ-OPP-2012-0829; FRL-9904-19
Acetochlor; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes tolerances for residues of acetochlor in or on sugar beets and peanuts. Monsanto Company requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA).
DATES: This regulation is effective January 22, 2014. Objections and requests for hearings must be received on or before March 24, 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-2012-0829, 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), EPA West Bldg., Rm. 3334, 1301 Constitution Ave. NW., Washington, DC 20460-0001. The
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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, Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460-0001; telephone number: (703) 305-7090; email address: RDFRNotices@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. 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).
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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 e-CFR site at http://www.ecfr.gov/cgi-bin/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title40/40tab_02.tpl.
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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-2012-0829 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 March 24, 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-2012-0829, 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.htm. Additional instructions on commenting or visiting the docket, along with more information about dockets generally, is available at http://www.epa.gov/dockets.
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Summary of Petitioned-for Tolerance
In the Federal Register of January 16, 2013 (78 FR 3377) (FRL-9375-
4), 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 2F8077) by Monsanto Company, 1300 I Street NW., Suite 450 East, Washington DC 20005. The petition requested that 40 CFR 180.470 be amended by establishing tolerances for residues of the herbicide, acetochlor, (2-chloro-2'-methyl-6'-ethyl-N-ethoxymethylacetanilide), and its metabolites containing either the 2-ethyl-6-methylaniline (EMA) or the 2-(1-hydroxyethyl)-6-methyl-aniline (HEMA) moiety, to be expressed as acetochlor equivalents, resulting from applications to soil or growing crops, in or on the following agricultural commodities: Beet, sugar, dried pulp at 0.5 parts per million (ppm); beet, sugar, molasses at 1.3 ppm; beet, sugar, roots at 0.3 ppm; beet, sugar, tops at 0.8 ppm; peanut at 0.2 ppm; peanut, hay at 6.0 ppm; and peanut, meal at 0.5 ppm. The petition also requested that EPA delete from 40 CFR 180.470(d) tolerances for indirect or inadvertent residues in beet, sugar, root at 0.05 ppm; and beet, sugar, tops at 0.05 ppm. That document referenced a summary of the petition prepared by Monsanto Company, the registrant, which is available in the docket, http://www.regulations.gov. A comment was received on the notice of filing. EPA's response to these comments is discussed in Unit IV.C.
Based upon review of the data supporting the petition, EPA has increased the proposed tolerances for peanut, hay and decreased the proposed tolerances for sugar beet, molasses and tops, and peanut, meal. The reason for these changes are explained in Unit IV.D.
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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 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 acetochlor including exposure resulting from the tolerances established by this action. EPA's assessment of exposures and risks associated with acetochlor 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
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subgroups of consumers, including infants and children.
Acetochlor has low acute toxicity by the oral, dermal, and inhalation routes of exposure and is minimally irritating to the eyes. A dermal irritation study indicates that it is a severe skin irritant. Acetochlor is also a strong dermal sensitizer.
Evidence of neurotoxicity was observed in acute and subchronic neurotoxicity screening studies in rats, developmental toxicity studies in rats, and subchronic and chronic studies in dogs. In addition to the nervous system, the major target organs affected in subchronic and chronic studies in rats, dogs, and mice exposed to acetochlor are the liver, thyroid (secondary to liver), kidney, testes, and erythrocytes. Species-specific target organs include the nasal olfactory epithelium in rats and the lungs in mice.
There is no evidence of increased qualitative or quantitative susceptibility of fetuses or offspring to acetochlor exposure in the developmental and reproduction toxicity studies in rats and rabbits. In two developmental toxicity studies in rats, fetal effects (increased early resorptions, post-implantation loss, and decreased fetal weight) occurred at doses that also resulted in maternal toxicity (mortality, clinical signs of toxicity, and decreased maternal body weight gain). In two rabbit developmental toxicity studies, there were no adverse fetal effects at the highest doses tested (190 milligrams/kilograms/day (mg/kg/day) and 300 mg/kg/day); whereas maternal toxicity (body weight loss) was seen at 190 mg/kg/day in one study. In three reproduction toxicity studies in rats, offspring effects (decreased pup weights in the first two studies; decreased pup weights, decreased F2 litter size at birth, and focal hyperplasia and polypoid adenomata in nasal epithelium of adult F1 offspring at study termination in the third study) occurred at the same or higher doses than those resulting in parental toxicity (decreased body weight or weight gain in the first two studies; focal hyperplasia and polypoid adenomata in nasal epithelium of adult F1 offspring at study termination in the third study). There was no evidence of reproductive toxicity observed at any dose tested in two of the three reproductive toxicity studies in rats. The third reproduction study in rats showed a decreased number of implantations at the highest dose tested of 216 mg/kg/day.
There was evidence of carcinogenicity in studies conducted with acetochlor in rats and mice. A 23-month mouse carcinogenicity study showed weak evidence for increased benign lung tumors in females, and a 78-week study showed weak evidence for increased benign lung tumors in males. The increases were considered equivocal, based on increases in benign tumors only, inconsistent dose-responses between the two studies, inconsistencies in the responses of males and females between the two studies, lack of pre-neoplastic lung lesions in the 23-month study (while the 78-week study showed an increase in bronchiolar hyperplasia), and the variable incidence of lung tumors known to occur in older mice.
Two carcinogenicity studies in rats showed an increase in nasal epithelial tumors and thyroid follicular cell tumors. Thyroid tumor incidence was relatively low, and there was evidence that the tumors were due to disruption of thyroid-pituitary homeostasis. There are acceptable mode of action data for the rat tumors (nasal olfactory epithelial tumors and thyroid follicular cell tumors) which are adequate to support a non-linear, margin of exposure (MOE), approach for assessment of cancer risk. The data show that, like the related compounds, alachlor and butachlor, tumor formation is dependent upon local cytotoxicity secondary to oxidative damage by a reactive quinone imine intermediate. The mechanistic data on nasal tumorigenesis of acetochlor in the rat, when considered together with the mutagenicity data on acetochlor and consistent findings in mechanistic and mutagenicity studies on the closely related compound alachlor, are considered adequate to demonstrate a cytotoxic, non-mutagenic mode of tumor induction.
Because a clear mode of action was demonstrated for the rat tumors, EPA based the cancer classification on the data from the mouse. Given the weakness of these data (benign lung tumors in male and female mice and histiocytic sarcomas in female mice), EPA has classified acetochlor as having ``Suggestive Evidence of Carcinogenic Potential'' and determined that linear quantification of carcinogenic potential would not be appropriate for the mouse tumors. The rat nasal tumors, with a point of departure (POD) of 10 mg/kg/day, are the most sensitive effect for cancer risk. The chronic population adjusted dose (cPAD), based on the no observed adverse effect level (NOAEL) of 2.0 mg/kg/day from the chronic dog study, will be protective of both non-cancer and cancer effects, including rat nasal tumors, thyroid tumors, and mouse tumors.
Specific information on the studies received and the nature of the adverse effects caused by acetochlor as well as the NOAEL and the lowest observed adverse effect level (LOAEL) from the toxicity studies can be found at http://www.regulations.gov in document Acetochlor Human Health Risk Assessment for Proposed New Uses of Acetochlor on Sugar Beet and Peanut at pages 41-53 in docket ID number EPA-HQ-OPP-2012-
0829.
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Toxicological Points of Departure/Levels of Concern
Once a pesticide's toxicological profile is determined, EPA identifies toxicological 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 acetochlor used for human risk assessment is shown in Table 1. of this unit.
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Table 1--Summary of Toxicological Doses and Endpoints for Acetochlor for Use in Human Health Risk Assessment
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Point of departure
Exposure/scenario and uncertainty/ RfD, PAD, for risk Study and toxicological effects
safety factors assessment
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Acute dietary (All populations).. NOAEL = 150 mg/kg/ Acute RfD = 1.5 mg/ Acute oral neurotoxicity in rats
day. kg/day. (MRID 45357501)
UFA = 10x........... aPAD = 1.5 mg/kg/ LOAEL = 500 mg/kg/day based on
UFH = 10x........... day. decreased motor activity in
FQPA SF = 1x........ females.
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Chronic dietary (All populations) NOAEL= 2.0 mg/kg/day Chronic RfD = 0.02 Chronic oral toxicity in beagle
UFA = 10x........... mg/kg/day. dogs (MRID 41565118)
UFH = 10x........... cPAD = 0.02 mg/kg/ LOAEL = 10 mg/kg/day based on
FQPA SF = 1x........ day. increased salivation and
histopathology in the testes,
kidney, and liver.
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Cancer (all routes).............. ``Suggestive Evidence of Carcinogenic Potential''. The cRfD of 0.02 mg/kg/day
will be protective of both non-cancer and cancer effects
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FQPA SF = Food Quality Protection Act Safety Factor. LOAEL = lowest observed adverse effect level. mg/kg/day =
milligram/kilogram/day. NOAEL= no observed adverse effect level. PAD = population adjusted dose (a = acute, c
= chronic). RfD = reference dose. UF = uncertainty factor. UFA = extrapolation from animal to human
(interspecies). UFH = potential variation in sensitivity among members of the human population (intraspecies).
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Exposure Assessment
1. Dietary exposure from food and feed uses. In evaluating dietary exposure to acetochlor, EPA considered exposure under the petitioned-
for tolerances as well as all existing acetochlor tolerances in 40 CFR 180.470. EPA assessed dietary exposures from acetochlor 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 acetochlor. In estimating acute dietary exposure, EPA used food consumption information from the U.S. Department of Agriculture's 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) for all commodities.
ii. Chronic exposure. In conducting the chronic dietary exposure assessment EPA used the food consumption data from the U.S. Department of Agriculture's NHANES/WWEIA. As to residue levels in food, EPA assumed anticipated residues from field trial data and 100 PCT for all commodities.
iii. Cancer. Based on the data summarized in Unit III.A.; based on the results of carcinogenicity studies in rats and mice, EPA classified acetochlor as having ``Suggestive Evidence of Carcinogenic Potential'' but determined that the chronic risk assessment will be protective of both non-cancer and cancer effects. Therefore, a separate exposure assessment to evaluate cancer risk is unnecessary.
2. Dietary exposure from drinking water. The Agency used screening level water exposure models in the dietary exposure analysis and risk assessment for acetochlor in drinking water. These simulation models take into account data on the physical, chemical, and fate/transport characteristics of acetochlor. 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 acetochlor for acute exposures are estimated to be 74.9 parts per billion (ppb) for surface water and 129.0 ppb for ground water. EDWCs of acetochlor for chronic exposures for non-cancer assessments are estimated to be 4.84 ppb for surface water and 82.6 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 129.0 ppb was used to assess the contribution to drinking water. For chronic dietary risk assessment, the water concentration of value 82.6 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). Acetochlor 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.''
The chloroacetanilides have been evaluated by the Agency and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) as a related group of chemicals for this purpose. Acetochlor is included in a Cumulative Assessment Group of chloroacetanilide pesticides. For purposes of a cumulative risk assessment, it was determined that the common mechanism of toxicity group consists of alachlor, acetochlor, and butachlor. Butachlor is excluded from the group for risk assessment purposes at present because there are no registered uses or tolerances for this chemical in the U.S. The group was selected based on common endpoints of:
i. Nasal turbinate tumors in rats, and a known mechanism of toxicity for development of these tumors.
ii. Induction of hepatic uridine diphosphate-glucuronosyl transferase (UDPGT), which results in increased incidence of thyroid follicular cell tumors secondary to disruption of pituitary-thyroid homeostasis. Thyroid effects were not included in the final
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cumulative assessment of the chloroacetanilide herbicides because they were determined to occur at excessively toxic dose levels, and therefore were not considered relevant to human risk assessment. Nasal tumors represent the most sensitive endpoint for both compounds.
An updated cumulative risk assessment of the chloroacetanilide pesticides acetochlor and alachlor conducted in April, 2007 provides an assessment of existing and new uses of those chemicals to date. Based on the most recent chloroacetanilide cumulative assessment group (CAG) cumulative risk assessment, cumulative risk is not of concern. A revised quantitative cumulative assessment was not conducted because the proposed amended use would not affect the cumulative risk results. Not only is acetochlor a very minor contributor to chloroacetanilide cumulative risk when compared to alachlor, but adding the use on sugar beets and peanuts will only have a minor impact on acetochlor exposure since only low residues occurred on sugar beet and peanut food commodities.
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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. No increase in susceptibility was seen in developmental toxicity studies in rats and rabbits or in three multi-generation reproductive toxicity studies in rats. Toxicity to offspring was observed at dose levels which were the same or greater than those causing maternal or parental toxicity. Based on the results of developmental and reproductive toxicity studies, there is no concern for increased qualitative and/or quantitative susceptibility of the young following exposure to acetochlor.
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 for acute dietary, chronic dietary, and dermal. That decision is based on the following findings:
i. The toxicity database for acetochlor is complete for the purpose of evaluating this tolerance petition.
ii. Evidence of neurotoxicity from exposure to acetochlor was observed in several oral studies. However, these effects were typically observed at high doses. The points of departure selected for risk assessment are protective of the potential neurotoxicity observed in the database.
iii. There is no evidence that acetochlor 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. No increase in susceptibility was seen in developmental toxicity studies in rats and rabbits or in three multi-generation reproductive toxicity studies in rats. Toxicity to offspring was observed at dose levels which were the same or greater than those causing maternal or parental toxicity. Based on the results of developmental and reproductive toxicity studies, there is no concern for increased qualitative and/or quantitative susceptibility following exposure to acetochlor.
iv. There are no residual uncertainties identified in the exposure databases. EPA made conservative (protective) assumptions in the ground and surface water modeling used to assess exposure to acetochlor in drinking water. The acute dietary exposure analysis used tolerance level residues and 100 PCT. The chronic dietary exposure analysis used field trial residues and 100 PCT. These assessments will not underestimate the exposure and risks posed by acetochlor.
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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 aPAD and cPAD. 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. In examining acute aggregate risk, the only pathway of exposure relevant to the acute time frame is dietary exposure. Therefore, the acute aggregate risk is comprised of exposures to acetochlor residues in food and drinking water and is equivalent to the acute dietary risk estimates. Using the exposure assumptions discussed in this unit for acute exposure, the acute dietary exposure from food and water to acetochlor will occupy 1.6% of the aPAD for all infants (
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