Pesticide Tolerances: Rimsulfuron
Federal Register: December 18, 2009 (Volume 74, Number 242)
Rules and Regulations
Page 67132-67137
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DOCID:fr18de09-17
ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 180
EPA-HQ-OPP-2009-0004; FRL-8796-9
Rimsulfuron; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
SUMMARY: This regulation amends tolerances for residues of rimsulfuron in or on corn, field, forage and corn, field, stover and establishes tolerances in or on grain, aspirated fractions; soybean, forage; soybean, hay; soybean, hulls; and soybean, seed. E.I du Pont de Nemours and Company requested these tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA).
DATES: This regulation is effective December 18, 2009. Objections and requests for hearings must be received on or before February 16, 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 ).
ADDRESSES: EPA has established a docket for this action under docket
Page 67133
identification (ID) number EPA-HQ-OPP-2009-0004. 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: Mindy Ondish, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (703) 605-0723; e-mail address: ondish.mindy@epa.gov.
SUPPLEMENTARY INFORMATION:
-
General Information
-
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.
-
How Can I Access Electronic Copies of this Document?
In addition to accessing electronically available documents at http://www.regulations.gov, you may access this Federal Register document electronically through the EPA Internet under the ``Federal
Register'' listings at http://www.epa.gov/fedrgstr. You may also access a frequently updated electronic version of EPA's tolerance regulations at 40 CFR part 180 through the Government Printing Office's e-CFR cite at http://www.gpoaccess.gov/ecfr. To access the OPPTS Harmonized Test
Guidelines referenced in this document, go directly to the guidelines at http://www.epa.gov/oppts and select ``Test Methods & Guidelines'' in the left side navigation menu.
-
Can I File an Objection or Hearing Request?
Under section 408(g) of FFDCA, 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-2009-0004 in the subject line on the first page of your submission. All requests must be in writing, and must be mailed or delivered to the Hearing Clerk as required by 40 CFR part 178 on or before February 16, 2010.
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 that is described in ADDRESSES. Information not marked confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA without prior notice. Submit this copy, identified by docket ID number
EPA-HQ-OPP-2009-0004, by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the on-line 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.
-
-
Petition for Tolerance
In the Federal Register of April 8, 2009 (74 FR 15971) (FRL-8407- 4), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21
U.S.C. 346a(d)(3), announcing the filing of pesticide petitions (PP 8F7431 and PP 8F7440) by E.I du Pont de Nemours and Company, Laurel Run
Plaza, P.O. Box 80038, Wilmington, DE 19880-0038. The petition requested that 40 CFR 180.478 be amended by establishing tolerances for residues of the herbicide rimsulfuron, N-((4,6-dimethoxypyrimidin-2- yl)aminocarbonyl)-3-(ethylsulfonyl)-2-pyridinesulfonamide, in or on corn, aspirated grain fractions at 1.02 parts per million (ppm); corn, field, forage at 0.4 ppm; corn, field grain at 0.01 ppm; and corn, field, stover at 2.5 ppm (PP 8F7440); and soybean, aspirated grain fractions at 4.51 ppm; soybean, forage at 0.25 ppm; soybean, hay at 1.2 ppm; soybean, hulls at 0.035 ppm; and soybean, seed at 0.01 ppm (PP 8F7431). That notice referenced a summary of the petition prepared by
E.I. du Pont de Nemours and Company, the registrant, which is available to the public 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 removed the proposed tolerances for corn, aspirated grain fractions at 1.02 ppm and soybean, aspirated grain fractions at 4.51 ppm and has replaced them with a tolerance on grain, aspirated fractions at 4.5 ppm. The tolerance level for soybean, hulls was rounded up from 0.035 ppm to 0.04 ppm. The existing tolerance level for corn, field, grain was maintained at 0.1 ppm to remain harmonized with Mexico's maximum residue limit (MRL). Finally, EPA has revised the tolerance expression for all existing and new rimsulfuron tolerances. The reasons for these changes are explained in Unit IV.D.
-
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
Page 67134
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 the petitioned-for tolerances for residues of rimsulfuron and its metabolites and degradates in or on corn, field, forage at 0.4 ppm; corn, field, stover at 2.5 ppm; grain, aspirated fractions at 4.5 ppm; soybean, forage at 0.25 ppm; soybean, hay at 1.2 ppm; soybean, hulls at 0.04 ppm; and soybean, seed at 0.01 ppm. EPA's assessment of exposures and risks associated with establishing tolerances follows.
-
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.
Rimsulfuron has low acute toxicity by oral, dermal, and inhalation routes of exposure. It is a moderate eye irritant and is not a dermal sensitizer. In subchronic and chronic toxicity studies in rats, toxic effects included decreased body weight, decreased body weight gain, increased relative liver and absolute kidney weights, and diuresis. At the higher dosage, decreased liver enzymes and bilirubin, fatty change, and hepatocellular hypertrophy were observed. In the chronic rat study, decreased body weight gain and increased liver weights were observed.
At the higher dosage, increased mortality was observed in males. In the subchronic study in mice, increased red blood cell (RBC) and hemoglobin, and decreased body weight gain and food efficiency were observed. In the chronic study in mice, decreased body weight, increased incidences of dilation and cysts in the glandular stomach, and degeneration of the testicular artery and tunica albuginea were observed. In the subchronic study in dogs, diuresis was indicated by urinary volume, platelet concentration and kidney weights accompanied by decreased urinary osmolality. In the chronic study in dogs, increased absolute liver and kidney weights, increased seminiferous tubule degeneration, and increased number of spermatid giant cells present in epididymides in males were observed. At the higher dosage, decreased mean body weight, decreased body weight gain, as well as increases in serum cholesterol levels, alkaline phosphatase activity, absolute liver, and relative liver and kidney weights were observed.
In the developmental toxicity study in rats, no toxicity was seen at the highest dose tested. In the developmental toxicity study in rabbits, and in the 2-generation reproduction toxicity study in rats, developmental/offspring toxicity was seen in the presence of maternal/ systemic toxicity and at similar dose levels. There is no quantitative or qualitative evidence of increased susceptibility following pre- and/ or postnatal exposures, and there are no concerns or residual uncertainties.
There was no evidence of potential immunotoxicity or neurotoxicity in the submitted studies.
Rimsulfuron was classified by EPA as a ``not likely'' human carcinogen based on the lack of evidence of carcinogenicity in studies conducted in rats and mice.
Specific information on the studies received and the nature of the adverse effects caused by rimsulfuron 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 ``Rimsulfuron Human Health Risk
Assessment for Proposed Section 3 Uses on Genetically Modified Field
Corn and Soybean'' , page 28 in docket ID number EPA-HQ-OPP-2009-0004.
-
Toxicological Endpoints
For hazards that have a threshold below which there is no appreciable risk, a toxicological point of departure (POD) is identified as the basis for derivation of reference values for risk assessment. The POD may be defined as the highest dose at which no adverse effects are observed (the NOAEL) in the toxicology study identified as appropriate for use in risk assessment. However, if a
NOAEL cannot be determined, the lowest dose at which adverse effects of concern are identified (the LOAEL) or a Benchmark Dose (BMD) approach is sometimes used for risk assessment. Uncertainty/safety factors (UFs) are used in conjunction with the POD to take into account uncertainties inherent in the extrapolation from laboratory animal data to humans and in the variations in sensitivity among members of the human population as well as other unknowns. Safety is assessed for acute and chronic dietary risks by comparing aggregate food and water exposure to the pesticide to the acute population adjusted dose (aPAD) and chronic population adjusted dose (cPAD). The aPAD and cPAD are calculated by dividing the POD by all applicable UFs. Aggregate short-, intermediate-
, and chronic-term risks are evaluated by comparing food, water, and residential exposure to the POD to ensure that the margin of exposure
(MOE) called for by the product of all applicable UFs is not exceeded.
This latter value is referred to as the Level of Concern (LOC).
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 greater than that 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 rimsulfuron used for human risk assessment can be found at http://www.regulations.gov in document ``Rimsulfuron Human Health Risk Assessment for Proposed
Section 3 Uses on Genetically Modified Field Corn and Soybean'' , page 18 in docket ID number EPA-HQ-OPP-2009-0004.
-
Exposure Assessment 1. Dietary exposure from food and feed uses. In evaluating dietary exposure to rimsulfuron, EPA considered exposure under the petitioned- for tolerances as well as all existing rimsulfuron tolerances in 40 CFR 180.478. EPA assessed dietary exposures from rimsulfuron 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 rimsulfuron;
Page 67135
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 CSFII. As to residue levels in food, EPA assumed tolerance- level residues and 100 percent crop treated (PCT) for all existing and new uses of rimsulfuron. iii. Cancer. Based on the lack of evidence of carcinogenicity observed in the 2-year rat and 18-month mouse carcinogenicity studies,
EPA classified rimsulfuron as a ``not likely'' human carcinogen.
Therefore, an exposure assessment for evaluating cancer risk is not needed for this chemical. iv. Anticipated residue and PCT information. EPA did not use anticipated residue or PCT information in the dietary assessment for rimsulfuron. 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 rimsulfuron in drinking water. These simulation models take into account data on the physical, chemical, and fate/transport characteristics of rimsulfuron. 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 First Index Reservoir Screening Tool (FIRST) and
Screening Concentration in Ground Water (SCI-GROW) models, the estimated drinking water concentrations (EDWCs) of rimsulfuron for acute exposures are estimated to be 5.596 parts per billion (ppb) for surface water and 0.016 ppb for ground water; and for chronic exposures are estimated to be 0.120 ppb for surface water and 0.016 ppb for ground water.
Modeled estimates of drinking water concentrations were directly entered into the dietary exposure model. For chronic dietary risk assessment, the water concentration of value 0.120 ppb was used to assess the contribution to drinking water. The surface water value was used in the chronic dietary assessment since it was higher than the groundwater value and, therefore, more protective. The acute surface water value is not relevant to this dietary assessment, as a toxic effect attributable to a single dose has not been identified for rimsulfuron. The cancer dietary risk assessment is also not relevant due to the lack of evidence of carcinogenicity in the conducted rat and mice toxicity studies. 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).
Rimsulfuron is not registered for any specific use patterns that would result in residential exposure. 4. Cumulative effects from substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to establish, modify, or revoke a tolerance, the
Agency consider ``available information'' concerning the cumulative effects of a particular pesticide's residues and ``other substances that have a common mechanism of toxicity.''
EPA has not found rimsulfuron to share a common mechanism of toxicity with any other substances, and rimsulfuron does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that rimsulfuron 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.
-
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 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. In the developmental toxicity in rats, no developmental toxicity was seen at the highest dose tested. In the developmental toxicity study in rabbits, and in the 2-generation study in rats, developmental/offspring toxicity was seen in the presence of maternal/systemic toxicity. In the rabbit study, fetal effects (production of only two viable fetuses) occurred at a higher dose (1,500 mg/kg/day) than the dose (500 mg/kg/day) resulting in maternal toxicity (death and reduced weight gain). In the reproduction study offspring effects (decreased mean body weight in F1 males, decreased body weight gain in F1 females, and decreased daily food consumption in F1 males) also occurred at a higher dose (1,316 mg/ kg/day) than the dose (M: 830 mg/kg/day; F: 1,021 mg/kg/day) resulting in parental/systemic toxicity (decreased body weight gain in males and females). Consequently, there is no quantitative or qualitative evidence of increased susceptibility following pre- and/or postnatal exposure to rimsulfuron. 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 rimsulfuron is adequate to assess potential for pre- and/or postnatal toxicity. In accordance with part 158 Toxicology Data requirements, an immunotoxicity study (870.7800), and acute and subchronic neurotoxicity studies (870.6200) are required for rimsulfuron. Despite the absence of specific immunotoxicity and neurotoxicity studies, EPA has evaluated the available toxicity data and has determined that there is no evidence that rimsulfuron either causes neurotoxic effects or directly targets the immune system, and, therefore, an additional UF is not needed to account for the lack of these studies. ii. There is no indication that rimsulfuron 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 rimsulfuron 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 chronic 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 rimsulfuron in drinking water. Residential exposure is not expected for rimsulfuron. These assessments will not underestimate the exposure and risks posed by rimsulfuron.
Page 67136
-
Aggregate Risks and Determination of Safety
EPA determines whether acute and chronic pesticide exposures are safe by comparing aggregate exposure estimates to the aPAD and cPAD.
The aPAD and cPAD represent the highest safe exposures, taking into account all appropriate SFs. EPA calculates the aPAD and cPAD by dividing the POD by all applicable UFs. For linear cancer risks, EPA calculates the probability of additional cancer cases 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 POD to ensure that the MOE called for by the product of all applicable UFs is not exceeded. 1. Acute risk. An acute aggregate risk assessment takes into account exposure estimates from acute 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, rimsulfuron 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 rimsulfuron from food and water will utilize
-
