Pesticide, food, and feed additive petitions: Interregional Research Project (No. 4),

[Federal Register: August 23, 2000 (Volume 65, Number 164)]

[Notices]

[Page 51314-51319]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr23au00-62]

ENVIRONMENTAL PROTECTION AGENCY

[PF-963; FRL-6738-9]

Notice of Filing a Pesticide Petition to Establish a Tolerance for a Certain Pesticide Chemical in or on Food

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

SUMMARY: This notice announces the initial filing of a pesticide petition proposing the establishment of regulations for residues of a certain pesticide chemical in or on various food commodities.

DATES: Comments, identified by docket control number PF-963, must be received on or before September 22, 2000.

ADDRESSES: Comments may be submitted by mail, electronically, or in person. Please follow the detailed instructions for each method as provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure proper receipt by EPA, it is imperative that you identify docket control number PF-963 in the subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Shaja R. Brothers, Registration Support Branch, Registration Division (7505W), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703) 308-3194; e- mail address: brothers.shaja@epa.gov.

SUPPLEMENTARY INFORMATION:

1. General Information

   1. Does this Action Apply to Me?

      You may be affected by this action if you are an agricultural producer, food manufacturer or pesticide manufacturer. Potentially affected categories and entities may include, but are not limited to:

      Examples of Categories

      NAICS codes

      potentially affected entities

      Industry

      111

      Crop production 112

      Animal production 311

      Food manufacturing 32532

      Pesticide manufacturing

      This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in the table could also

      [[Page 51315]]

      be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether or not this action might apply to certain entities. If you have questions regarding the applicability of this action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT.

   2. How Can I Get Additional Information, Including Copies of this Document and Other Related Documents?

      1. Electronically. You may obtain electronic copies of this document, and certain other related documents that might be available electronically, from the EPA Internet Home Page at http://www.epa.gov/. To access this document, on the Home Page select ``Laws and Regulations,'' ``Regulations and Proposed Rules,'' and then look up the entry for this document under the ``Federal Register--Environmental Documents.'' You can also go directly to the Federal Register listings at http://www.epa.gov/fedrgstr/.

      2. In person. The Agency has established an official record for this action under docket control number PF-963. The official record consists of the documents specifically referenced in this action, any public comments received during an applicable comment period, and other information related to this action, including any information claimed as confidential business information (CBI). This official record includes the documents that are physically located in the docket, as well as the documents that are referenced in those documents. The public version of the official record does not include any information claimed as CBI. The public version of the official record, which includes printed, paper versions of any electronic comments submitted during an applicable comment period, is available for inspection in the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

   3. How and to Whom Do I Submit Comments?

      You may submit comments through the mail, in person, or electronically. To ensure proper receipt by EPA, it is imperative that you identify docket control number PF-963 in the subject line on the first page of your response.

      1. By mail. Submit your comments to: Public Information and Records Integrity Branch (PIRIB), Information Resources and Services Division (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.

      2. In person or by courier. Deliver your comments to: Public Information and Records Integrity Branch (PIRIB), Information Resources and Services Division (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

      3. Electronically. You may submit your comments electronically by e-mail to: ``opp-docket@epa.gov,'' or you can submit a computer disk as described above. Do not submit any information electronically that you consider to be CBI. Avoid the use of special characters and any form of encryption. Electronic submissions will be accepted in Wordperfect 6.1/ 8.0 or ASCII file format. All comments in electronic form must be identified by docket control number PF-963. Electronic comments may also be filedonline at many Federal Depository Libraries.

   4. How Should I Handle CBI That I Want to Submit to the Agency?

      Do not submit any information electronically that you consider to be CBI. You may claim information that you submit to EPA in response to this document as CBI by marking any part or all of that information as CBI. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. In addition to one complete version of the comment that includes any information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public version of the official record. Information not marked confidential will be included in the public version of the official record without prior notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person identified under FOR FURTHER INFORMATION CONTACT.

   5. What Should I Consider as I Prepare My Comments for EPA?

      You may find the following suggestions helpful for preparing your comments:

      1. Explain your views as clearly as possible.

      2. Describe any assumptions that you used.

      3. Provide copies of any technical information and/or data you used that support your views.

      4. If you estimate potential burden or costs, explain how you arrived at the estimate that you provide.

      5. Provide specific examples to illustrate your concerns.

      6. Make sure to submit your comments by the deadline in this notice.

      7. To ensure proper receipt by EPA, be sure to identify the docket control number assigned to this action in the subject line on the first page of your response. You may also provide the name, date, and Federal Register citation.

2. What Action is the Agency Taking?

   EPA has received a pesticide petition as follows proposing the establishment and/or amendment of regulations for residues of a certain pesticide chemical in or on various food commodities under section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a. EPA has determined that this petition contains data or information regarding the elements set forth in section 408(d)(2); however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data support granting of the petition. Additional data may be needed before EPA rules on the petition.

   List of Subjects

   Environmental protection, Agricultural commodities, Feed additives, Food additives, Pesticides and pests, Reporting and recordkeeping requirements.

   Dated: August 10, 2000. James Jones, Director, Registration Division, Office of Pesticide Programs.

   Summary of Petition

   The petitioner summary of the pesticide petition is printed below as required by section 408(d)(3) of the FFDCA. The summary of the petition was prepared by the petitioner and represents the view of the petitioner. EPA is publishing the petition summary verbatim without editing it in any way. The petition summary announces the availability of a description of the analytical methods available to EPA for the detection and measurement of the pesticide chemical residues or an explanation of why no such method is needed.

   [[Page 51316]]

   Interregional Research Project Number 4

   PP 0E6085

   EPA has received a pesticide petition (PP 0E6085) from the Interregional Research Project Number 4, 681 US Highway 1 South, North Brunswick, NJ 08902-3390 proposing, pursuant to section 408(d) of the FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a tolerance for residues of halosulfuron-methyl in or on the raw agricultural commodity (RAC) cucumber/squash subgroup at 0.5 parts per million (ppm). EPA has determined that the petition contains data or information regarding the elements set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data support granting of the petition. Additional data may be needed before EPA rules on the petition. This notice includes a summary of the petition prepared by Monsanto Company, St. Louis, MO 63167.

   1. Residue Chemistry

      1. Plant metabolism. The metabolism of halosulfuron-methyl as well as the nature of the residues in plants is adequately understood for purposes of this tolerance.

      2. Analytical method. A practical analytical method, gas chromatography with a nitrogen specific detector which detects and measures residues of halosulfuron-methyl is available for enforcement purposes with a limit of detection that allows monitoring of food with residues at or above the levels set in these tolerances. This enforcement method has been submitted to the Food and Drug Administration for publication in the Pesticide Analytical Manual (PAM II).

      3. Magnitude of residues. In cucumber and squash residue studies, there were no quantifiable residues found in the raw agricultural commodities using an analytical method with limit of quantitation (LOQ) of 0.1 ppm and 0.5 ppm, respectively.

   2. Toxicological Profile

      1. Acute toxicity. Acute toxicological studies placed the technical-grade halosulfuron-methyl in Toxicity Category III. A 90-day feeding study in rats resulted in a lowest observed adverse effect level (LOAEL) of 497 milligrams/kilograms/day (mg/kg/day) in males and 640 mg/kg/day in females, and a no observed adverse effect level (NOAEL) of 116 mg/kg/day in males and 147 mg/kg/day in females.

      2. Genotoxicity. Bacterial/mammalian microsomal mutagenicity assays were performed and found not to be mutagenic. Two mutagenicity studies were performed to test gene mutation and found to produce no chromosomal aberrations or gene mutations in cultured Chinese hamster ovary cells. An in vivo mouse micronucleus assay did not cause a significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow cells. A mutagenicity study was performed on rats and found not to induce unscheduled DNA synthesis in primary rat hepatocytes.

      3. Reproductive and developmental toxicity. A developmental toxicity study in rats resulted in a developmental LOAEL of 750 mg/kg/ day, based on decreases in mean litter size and fetal body weight, and increases in resorptions, resorptions/dam, post-implantation loss and in fetal and litter incidences of soft tissue and skeletal variations, and a developmental NOAEL of 250 mg/kg/day. Maternal LOAEL was 750 mg/ kg/day based on increased incidence of clinical observations, reduced body weight gains, and reduced food consumption and food efficiency. The maternal NOAEL was 250 mg/kg/day.

         A developmental toxicity study in rabbits resulted in a developmental LOAEL of 150 mg/kg/day, based on decreased mean litter size and increases in resorptions, resorptions/dam and post- implantation loss, and a developmental NOAEL of 50 mg/kg/day. The maternal LOAEL was 150 mg/kg/day based on reduced body weight gain and reduced food consumption and food efficiency. The maternal NOAEL was 50 mg/kg/day.

         A dietary 2-generation reproduction study in rats resulted in parental toxicity at 223.2 mg/kg/day in males and 261.4 mg/kg/day in females in the form of decreased body weights, decreased body weight gains, and reduced food consumption during the premating period. Very slight effects were noted in body weight of the offspring at this dose. This effect was considered to be developmental toxicity (developmental delay) rather than a reproductive effect. No effects were noted on reproductive or other developmental toxicity parameters. The systemic/ developmental toxicity LOAEL was 223.2 mg/kg/day in males and 261.4 mg/ kg/day in females; the systemic/developmental toxicity NOAEL was 50.4 mg/kg/day in males and 58.7 mg/kg/day in females. The reproductive LOAEL was greater than 223.2 mg/kg/day in males and 261.4 mg/kg/day in females; the reproductive NOAEL was equal to or greater than 223.2 mg/ kg/day in males and 261.4 mg/kg/day in females.

      4. Subchronic toxicity. A 21-day dermal toxicity study in rats resulted in a NOAEL of 100 mg/kg/day in males and greater than 1,000 mg/kg/day in females. The only treatment-related effect was a decrease in body weight gain of the 1,000 mg/kg/day group in males.

      5. Chronic toxicity. A 1-year chronic oral study in dogs resulted in a LOAEL of 40 mg/kg/day based on decreased weight gain and a NOAEL of 10 mg/kg/day for systemic toxicity. A 78-week carcinogenicity study was performed on mice. Males in the 971.6 mg/kg/day group had decreased body weight gains and an increased incidence of microconcretion/ mineralization in the testis and epididymis. No treatment-related effects were noted in females. Based on these results, a LOAEL of 971.9 mg/kg/day was established in males and NOAELs of 410 mg/kg/day in males and 1,214.6 mg/kg/day in females were established. The study showed no evidence of carcinogenicity. A combined chronic toxicity/ carcinogenicity study in rats resulted in a LOAEL of 225.2 mg/kg/day in males and 138.6 mg/kg/day in females based on decreased body weight gains, and a NOAEL of 108.3 mg/kg/day in males and 56.3 mg/kg/day in females. The study showed no evidence of carcinogenicity.

      6. Animal metabolism. EPA stated that the nature of the residue in ruminants was determined to be adequately understood. In the tissues and milk of goats, the major extractable residue was the unmetabolized parent compound. Based on the low residues of the parent compound in corn grain and the low transfer of residues in the metabolism study, tolerances on poultry products were not required. In the rat metabolism study, parent compound was absorbed rapidly but incompletely. Excretion was relatively rapid at all doses tested with majority of radioactivity eliminated in the urine and feces by 72 hours. Fecal elimination of parent was apparently the result of unabsorbed parent.

      7. Metabolite toxicology. The toxicology studies listed below were conducted with the 3-CSA metabolite. Based on the toxicological data of the 3-CSA metabolite, EPA concluded that it has lower toxicity compared to the parent compound and that it should not be included in the tolerance expression. The residue of concern is the parent compound only.

         i. A 90-day rat feeding study resulted in a LOAEL in males of >20,000 ppm

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         and a NOAEL of 20,000 ppm (1,400 mg/kg/day). In females, the LOAEL is 10,000 ppm (772.8 mg/kg/day) based on decreased body weight gains and a NOAEL of 1,000 ppm (75.8 mg/kg/day).

         ii. A developmental toxicity resulted in a LOAEL for maternal toxicity of >1,000 mg/kg/day based on the absence of systemic toxicity, a NOAEL of 1,000 mg/kg/day. The developmental LOAEL is >1,000 mg/kg/day and the NOAEL is 1,000 mg/kg/day.

         iii. The microbial reverse gene mutation did not produce any mutagenic effect while the mammalian cell gene mutation/Chinese hamster ovary cells did not show a clear evidence of mutagenic effect in the Chinese hamster ovary cells.

         iv. The mouse micronucleus assay did not show any clastogenic or aneugenic effect.

      8. Endocrine disruption. No specific tests have been conducted with halosulfuron-methyl to determine whether the chemical may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen or other endocrine effects. However, there were no significant findings in other relevant toxicity tests, i.e., teratology and multi-generation reproduction studies, which would suggest that halosulfuron-methyl produces effects characteristic of the disruption of the estrogenic hormone.

   3. Aggregate Exposure

      1. Dietary exposure. Tolerances have been established (40 CFR 180.479) for residues of halosulfuron-methyl in or on a variety of plant and animal RACs including field corn at 0.05 ppm, grain sorghum (milo) at 0.05 ppm, sweet corn (kernel + cobs with husks removed) at 0.05 ppm, pop corn grain at 0.05 ppm, sugarcane cane at 0.05 ppm, tree nuts nutmeat at 0.05 ppm, pistachio nuts nutmeat at 0.05 ppm, cotton undelinted seed at 0.05 ppm, and rice grain at 0.05 ppm; and secondary tolerances in meat and meat byproducts at 0.1 ppm (cattle, goats, hogs, horses, and sheep). Tolerances for the fruiting vegetable crop group 8 have been proposed by Gowan Company at 0.05 ppm. An additional tolerance is herein being requested for the crop group 9B, squash/ cucumber subgroup of the cucurbit vegetable group, at 0.5 ppm.

         i. Food--a. Acute exposure. For purposes of assessing the potential dietary exposure from food under existing and proposed tolerances, aggregate exposure is based on the Theoretical Maximum Residue Contribution (TMRC) which is an estimate of the level of residues consumed daily if each food item contained pesticide residues equal to the tolerance. The calculated TMRC value using 95th percentile consumption data was 0.0036 mg/kg body weight/day or 0.72% acute reference dose (RfD) for the general US population; 0.0081 mg/kg/day or 1.61% acute RfD for non-nursing infants less than 1 year old; and 0.0022 mg/kg/day or 0.45% acute RfD for females 13+ years not pregnant or nursing. TMRC is obtained by multiplying the tolerance levels for each commodity by the daily consumption of the food forms of that commodity eaten by the U.S. population and various population subgroups. In conducting this exposure assessment, conservative assumptions were made, e.g., 100% of all commodities will contain halosulfuron-methyl residues and those residues would be at the level of their respective tolerances. This results in a large overestimate of human exposure. Given the conservative approach, dietary exposures to halosulfuron-methyl are less 2% acute RfD for all sub-populations. Food consumption data from DEEM software (Novigen Sciences, Inc., version 6.73) were used in the calculation. Corn and sorghum forage and fodder are fed to animals; thus, exposure of humans to residues from these commodities might result if such residues are transferred to meat, milk, poultry or eggs. However, based on the results of animal metabolism and feeding studies and the amount of halosulfuron-methyl expected in animal feeds, it can be concluded that there is no reasonable expectation that residues of halosulfuron-methyl will exceed existing tolerances in meat.

         b. Chronic exposure. The chronic RfD is 0.1 mg/kg/day. The calculated TMRC value for the U.S. population is 0.0011 mg/kg/day or 1.1% RfD; 0.0017 mg/kg/day or 1.7% cRfD for infants less than 1-year old; 0.0035 mg/kg/day or 3.5% cRfD for children 1-6 years old; and 0.0009 mg/kg/day for 0.9% cRfD for females 13+ years not pregnant or nursing.

         c. Short- and intermediate-term exposure. The short-term NOAEL for females 13+ years and infants and children is 50 mg/kg/day. Comparing the NOAEL with the chronic food exposure from DEEM analysis of 0.0009 mg/kg/day for females 13+ and 0.0035 mg/kg/day for children 1-6 years old results in food MOEs of 55,560 and 14,280, respectively. The intermediate-term NOAEL is 10 mg/kg/day, comparing the NOAEL with the chronic food exposure from DEEM analysis of 0.0035 mg/kg/day for children (1-6 years old) results in a food MOE of 2,860.

         d. Chronic risk-carcinogenic. Halosulfuron-methyl has been classified as a Group E chemical based upon the lack of evidence of carcinogenicity in mice and rats, and has been classified as a not likely human carcinogen.

         ii. Drinking water. There is no Maximum Contaminant Level (MCL) established for residues of halosulfuron-methyl. It is not listed for MCL development or drinking water monitoring under the Safe Drinking Water Act nor is it a target of EPA's National Survey of Wells for Pesticides. Monsanto is not aware of any halosulfuron-methyl detections in any wells, ponds, or lakes resulting from its use in the United States. The drinking water estimated environmental concentrations (EECs) in ground water (acute and chronic) is 0.008 mg/L. The EECs (acute and chronic) for surface water are 4.3 mg/L and 1.1 mg/L, respectively. These estimates are based on a maximum application rate of 0.063 lbs. active ingredient per acre which may be applied twice per season.

         a. Acute exposure and risk. Acute drinking water levels of concern (DWLOCs) have been calculated for exposure to halosulfuron-methyl in drinking water for the relevant population subgroups of females 13+ years and infants and children. The acute DWLOC is 15,000 mg/L for females 13+ years and 5,000 mg/L for infants and children. The calculated DWLOCs are significantly higher than the drinking water EECs for ground water (0.008 mg/L) and surface water (4.3 mg/L).

         b. Chronic exposure and risk. Chronic DWLOCs have been calculated for exposure to halosulfuron-methyl in drinking water for the U.S. population (48 contiguous states) and the relevant subgroups of females 13+ years and infants and children. The chronic DWLOC is 3,500 mg/L for the U.S. population, 3,000 mg/L for females 13+ years, and 1,000 mg/L for infants and children. The calculated DWLOCs are significantly higher than the drinking water EECs for ground water (0.008 mg/L) and surface water (1.1 mg/L).

         c. Short- and intermediate-term exposure and risk. Short-term and intermediate-term DWLOCs have been calculated for exposure to halosulfuron-methyl in drinking water for the relevant population subgroups. The short-term DWLOC is 10,000 mg/L for females 13+ years and 3,700 mg/L for infants and children. The intermediate-term DWLOC is 590 mg/L for adult males, 57 mg/L for females 13+ years, and 160 mg/L for infants and children. The calculated intermediate-term DWLOCs are significantly higher than

         [[Page 51318]]

         the chronic drinking water EECs for surface water (1.1 mg/L). The calculated short-term DWLOCs are significantly higher than the acute drinking water EECs for ground water (0.008 mg/L) and surface water (4.3 mg/L).

         d. Conclusion. Monsanto has concluded that potential levels of halosulfuron-methyl in soil and water do not appear to have significant toxicological effects on humans or animals and presents a negligible risk. Based on the very low level of mammalian toxicity, lack of other toxicological concerns and low use rates, there is reasonable certainty that no harm will result from exposure to halosulfuron-methyl via drinking water sources.

      2. Non-dietary exposure. Halosulfuron-methyl is labeled for use on commercial and residential turf and other non-crop sites. For residential applicators, short- and intermediate-term exposure may occur. Chronic exposure (>6 months of continuous exposure) are not expected.

         i. Acute exposure and risk. There is potential for exposure to halosulfuron-methyl by homeowner. However, since endpoints for acute dermal or inhalation were not identified, the use of halosulfuron- methyl on residential non-food sites is not expected to pose an unacceptable acute risk.

         ii. Chronic exposure and risk. Chronic exposures for residential use of halosulfuron-methyl are not expected and a chronic non-dietary endpoint was not identified, therefore the use on residential non-food sites is not expected to pose an unacceptable chronic risk.

         iii. Short- and intermediate-term exposure and risk. There is potential for short- or intermediate-term dermal exposure to residential handlers; therefore, residential exposure assessments were conducted to assess the following post-application exposure scenarios: Dermal exposure to residues on turf; children's incidental non-dietary ingestion of residues on residential lawn from hand-to-mouth transfer; and children's ingestion of pesticide-treated turfgrass.

         The short-term dermal MOE for residential handlers is 4,200 which is significantly greater than the minimum acceptable MOE of 100.

         The short-term dermal MOE for exposure from treated lawns for adult males, adult females, and children are 390, 330, and 420, respectively, which are significantly greater than the minimum acceptable MOE of 100. The intermediate-term dermal MOE for exposure from treated lawns for adult males, adult females, and children are 120, 100, and 130, respectively, which are equal to or greater than the minimum acceptable MOE of 100. Therefore the use of halosulfuron-methyl on residential non-food sites is not expected to pose an unacceptable short- or intermediate-term risk.

         The short- and intermediate-term oral MOE for hand-to-mouth transfer for children are 4,900 and 1,500, respectively, which are significantly greater than the minimum acceptable MOE of 100. Therefore the use of halosulfuron-methyl on residential non-food sites is not expected to pose an unacceptable short- or intermediate-term risk.

         The short- and intermediate-term oral MOE for incidental ingestion by children are 210,000 and 66,000, respectively, which are significantly greater than the minimum acceptable MOE of 100. Therefore the use on residential non-food sites is not expected to pose an unacceptable short- or intermediate-term risk.

   4. Cumulative Effects

      Halosulfuron-methyl belongs to the sulfonyl urea class of chemistry. The mode of action of halosulfuron-methyl is the inhibition of the plant enzyme aceto lactase synthetase (ALS), which is essential for the production of required amino acid in plants. Although other registered sulfonyl ureas may have similar herbicidal mode of action, there is no information available to suggest that these compounds exhibit a similar toxicity profile in the mammalian system that would be cumulative with halosulfuron-methyl. Thus, consideration of a common mechanism of toxicity is not appropriate at this time. Monsanto is considering only the potential risks of halosulfuron-methyl in its aggregate exposure assessment.

   5. Safety Determination

      1. U.S. population--i. Acute risk. Aggregate exposure risk includes exposure from food and water. The risk from acute ``food only'' exposure is less than 2% of the RfD for all population groups which is less than the EPA's level of concern. The lowest DWLOC calculated was 5,000 mg/L for infants and children. The calculated DWLOC for females (13+ years) was 15,000 mg/L. For both subgroups, the DWLOC is significantly higher than the drinking water EECs for acute ground water (0.008 mg/L) and surface water (4.3 mg/L). Therefore, the risk from aggregate exposure to halosulfuron-methyl residues from all anticipated dietary exposure routes does not pose appreciable risks to human health.

         ii. Chronic risk. Aggregate chronic exposure to halosulfuron-methyl from ``food only'' exposure utilizes 3.5% of the RfD for the most sensitive subgroup, children (1-6 years). The lowest DWLOC calculated was 1,000 mg/L for infants and children which is significantly higher than the drinking water EECs for chronic ground water (0.008 mg/L) and surface water (1.1 mg/L). Therefore, the aggregate risk from chronic exposure to halosulfuron-methyl residues from all anticipated dietary exposures does not pose appreciable risks to human health.

         iii. Short- and intermediate-term risk--a. Short-term aggregate exposure takes into account chronic dietary food and water plus short- term residential exposure. For halosulfuron-methyl, EPA has determined that it is appropriate to aggregate exposure via oral exposure route (food and water) with those via oral and dermal exposure routes from residential uses. The MOEs for ``food only'' and residential exposure routes are 22,400 and 330 for females 13+ years. Short-term DWLOC for females 13+ is 10,000 mg/L which is substantially higher than the drinking water EECs for acute surface water (4.3 mg/L). The food only and residential (oral and dermal) MOEs are well above the acceptable short-term aggregate MOE of 100. Therefore, exposure to halosulfuron- methyl residues resulting from current and proposed uses does not pose a short-term aggregate risk.

         b. Intermediate-term aggregate exposure takes into account chronic dietary food and water plus intermediate-term residential exposure. The MOEs for ``food only'' and residential exposure routes are 13,700 and 120 for adult males, and 11,500 and 100 for females 13+ years. The intermediate-term DWLOCs are 590 mg/L and 57 mg/L, respectively, for adult males and females 13+. Intermediate-term DWLOCs are substantially higher than the drinking water EECs for chronic surface water (1.1 mg/ L). The food only and residential (dermal) MOEs are above the acceptable short-term aggregate MOE of 100. Therefore, exposure to halosulfuron-methyl residues resulting from current and proposed uses does not pose a intermediate-term aggregate risk.

         iv. Aggregate cancer risk. Halosulfuron-methyl has been classified as a Group E chemical based upon the lack of evidence of carcinogenicity in mice and rats, and has been classified as a not likely human carcinogen.

         v. Conclusion. Based upon these risk assessments, Monsanto concluded that there is a reasonable certainty that no harm will result from aggregate exposure to halosulfuron-methyl

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         residues resulting from current and proposed uses.

      2. Infants and children--i. Safety factor. FFDCA section 408 provides that EPA may apply an additional safety factor (up to 10) in the case of threshold effects for infants and children to account for prenatal and postnatal toxicity and the completeness of the data base. Except for the pending request for a developmental neurotoxicity study, the toxicity data base is complete for halosulfuron-methyl. Based upon reliable toxicity data, the use of an additional 10x safety factor is not warranted. Dietary assessments do not indicate a level of concern for potential risks to infants and children based upon the low use rates of halosulfuron-methyl and that the results of field and animal RAC studies conclude that detectable residues are not expected in human foods.

         ii. Acute risk. The acute RfD was determined to be 0.5 mg/kg/day based upon the developmental rabbit study. The percent of the acute RfD occupied is 0.72% for the U.S. population, 0.45% for females 13+ years not pregnant or nursing, and 1.61% for non-nursing infants (1 year old). The subgroup with the highest exposure were non-nursing infants and children. The DWLOC for acute exposure for infants and children is 5,000 mg/L and is significantly less than the maximum concentration of halosulfuron-methyl in drinking water (0.008 mg/L in ground water and 4.3 mg/L in surface water).

         iii. Chronic risk. The cRfD was determined to be 0.1 mg/kg/day based upon the chronic dog study. The percent of RfD occupied is 3.5% for the most sensitive subgroup, children (1-6 years old). The DWLOC for chronic exposure for infants and children is 1,000 mg/L and is significantly less than the maximum concentration of halosulfuron- methyl in drinking water (0.008 mg/L in ground water and 1.1 mg/L in surface water).

         iv. Short- and intermediate-term risk. An aggregate exposure estimate and risk assessment was calculated for post-application exposure to halosulfuron-methyl from treated lawns. Short-term MOEs for food, residential oral, and residential dermal are 6,200, 4,900, and 420, respectively, for infants and children. Intermediate-term MOEs for food, residential oral, and residential dermal are 2,900, 1,500, and 130, respectively, for children and infants. The short- and intermediate-term DWLOCs for infants and children were 3,700 and 160 mg/L, respectively, which are substantially higher than the drinking water EECs for acute surface water (4.3 mg/L) and chronic surface water (1.1 mg/L).

         v. Conclusion. Therefore, based on complete and reliable toxicity data and the conservative exposure assessment, Monsanto concludes that there is reasonable certainty that no harm will result to infants and children from aggregate exposure to halosulfuron-methyl residues with respect to the proposed new uses on squash/cucumber subgroup of the cucurbit vegetable group.

   6. International Tolerances

      Maximum residue levels have not been established for residues of halosulfuron-methyl on any food or feed crop by the Codex Alimentarius Commission.

      [FR Doc. 00-20997Filed8-22-00; 8:45 am]

      BILLING CODE 6560-50-F