03-6711. Flufenacet; Notice of Filing Pesticide Petitions to Establish Tolerances 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 flufenacet in or on various food commodities.

DATES:

Comments, identified by docket ID number OPP-2003-0056, must be received on or before April 21, 2003.

ADDRESSES:

Comments may be submitted electronically, by mail, or through hand delivery/courier. Follow the detailed instructions as provided in Unit I. of the SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT:

James A. Tompkins, Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: [phone]; e-mail address: [e-mail].

SUPPLEMENTARY INFORMATION:

I. General Information

A. 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:

• Crop production (NAICS 111)
• Animal production (NAICS 112)
• Food manufacturing (NAICS 311)
• Pesticide manufacturing (NAICS 32532)

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 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.

B. How Can I Get Copies of this Document and Other Related Information?

1. Docket. EPA has established an official public docket for this action under docket identification (ID) number OPP-2003-0056. The official public docket consists of the documents specifically referenced in this action, any public comments received, and other information related to this action. Although a part of the official docket, the public docket does not include Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The official public docket is the collection of materials that is available for public viewing at the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The docket telephone number is [phone].

2. Electronic access. You may access this Federal Register document electronically through the EPA Internet under the “Federal Register” listings at http://www.epa.gov/​fedrgstr/​.

An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at http://www.epa.gov/​edocket/​ to submit or view public comments, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available electronically. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in Unit I.B.1. Once in the system, select “search,” then key in the appropriate docket ID number.

Certain types of information will not be placed in the EPA Dockets. Information claimed as CBI and other information whose disclosure is restricted by statute, which is not included in the official public docket, will not be available for public viewing in EPA's electronic public docket. EPA's policy is that copyrighted material will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. To the extent feasible, publicly available docket materials will be made available in EPA's electronic public docket. When a document is selected from the index list in EPA Dockets, the system will identify whether the document is available for viewing in EPA's electronic public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in Unit I.B. EPA intends to work towards providing electronic access to all of the publicly available docket materials through EPA's electronic public docket.

For public commenters, it is important to note that EPA's policy is that public comments, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change, unless the comment contains copyrighted material, CBI, or other information whose disclosure is restricted by statute. When EPA identifies a comment containing copyrighted material, EPA will provide a reference to that material in the version of the comment that is placed in EPA's electronic public docket. The entire printed comment, including the copyrighted material, will be available in the public docket.

Public comments submitted on computer disks that are mailed or delivered to the docket will be transferred to EPA's electronic public docket. Public comments that are mailed or delivered to the docket will be scanned and placed in EPA's electronic public docket. Where practical, physical objects will be photographed, and the photograph will be placed in EPA's electronic public docket along with a brief description written by the docket staff.

C. How and To Whom Do I Submit Comments?

You may submit comments electronically, by mail, or through hand delivery/courier. To ensure proper receipt by EPA, identify the appropriate docket ID number in the subject line on the first page of your comment. Please ensure that your comments are submitted within the specified comment period. Comments received after the close of the comment period will be marked “late.” EPA is not required to consider these late comments. If you wish to submit CBI or information that is otherwise protected by statute, please follow the instructions in Unit I.D. Do not use EPA Dockets or e-mail to submit CBI or information protected by statute.

1. Electronically. If you submit an electronic comment as prescribed in this unit, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your comment. Also include this contact information on the outside of any disk or CD ROM you submit, and in any cover letter accompanying the disk or CD ROM. This ensures that you can be identified as the submitter of the comment and allows EPA to contact you in case EPA cannot read your comment due to technical difficulties or needs further information on the substance of your comment. EPA's policy is that EPA will not edit your comment, and any identifying or contact information provided in the body of a comment will be included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment.

i. EPA Dockets. Your use of EPA's electronic public docket to submit comments to EPA electronically is EPA's preferred method for receiving comments. Go directly to EPA Dockets at http://www.epa.gov/​edocket,, and follow the online instructions for submitting comments. Once in the system, select “search,” and then key in docket ID number OPP-2003-0056. The system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your comment.

ii. E-mail. Comments may be sent by e-mail to [e-mail], Attention: Docket ID Number OPP-2003-0056. In contrast to EPA's electronic public docket, EPA's e-mail system is not an “anonymous access” system. If you send an e-mail comment directly to the docket without going through EPA's electronic public docket, EPA's e-mail system automatically captures your e-mail address. E-mail addresses that are automatically captured by EPA's e-mail system are included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket.

iii. Disk or CD ROM. You may submit comments on a disk or CD ROM that you mail to the mailing address identified in Unit I.C.2. These electronic submissions will be accepted in WordPerfect or ASCII file format. Avoid the use of special characters and any form of encryption.

2. By mail. Send your comments to: Public Information and Records Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001, Attention: Docket ID Number OPP-2003-0056.

3. By hand delivery or courier. Deliver your comments to: Public Information and Records Integrity Branch (PIRIB), Office of Pesticide Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket ID Number OPP-2003-0056. Such deliveries are only accepted during the docket's normal hours of operation as identified in Unit I.B.1.

D. How Should I Submit CBI to the Agency?

Do not submit information that you consider to be CBI electronically through EPA's electronic public docket or by e-mail. You may claim information that you submit to EPA as CBI by marking any part or all of that information as CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is 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 docket and EPA's electronic public docket. If you submit the copy that does not contain CBI on disk or CD ROM, mark the outside of the disk or CD ROM clearly that it does not contain CBI. Information not marked as CBI will be included in the public docket and EPA's electronic public docket without prior notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person listed under FOR FURTHER INFORMATION CONTACT.

E. 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 ID 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.

II. 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 FFDCA 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: March 10, 2003.

Debra Edwards,

Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

The petitioner's summary of the pesticide petition is printed below as required by FFDCA section 408(d)(3). The summary of the petition was prepared by the petitioner and represents the view of the petitioner. 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.

Bayer CropScience

PP 6F4631 and OF6095

EPA has received pesticide petitions (6F4631 and 0F6095) from Bayer CropScience, P.O. Box 12014, 2 T.W. Alexander Drive, Research Triangle Park, NC 27709 proposing, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR 180.527(a) by establishing permanent tolerance[s] for residues of the herbicide flufenacet; N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl]oxy]acetamide and metabolites containing the 4-fluoro-N-methylethyl benzenamine moiety in or on the raw agricultural commodities: corn, field, forage at 0.4 parts per million (ppm); corn, field, grain at 0.05 ppm; corn, field, stover at 0.4 ppm; soybean, seed at 0.1 ppm (PP 6F4631); cattle, fat at 0.05 ppm; cattle, kidney at 0.5 ppm; cattle, meat at 0.05 ppm; cattle, meat byproducts at 0.1 ppm; goat, fat at 0.05 ppm; goat, kidney at 0.5 ppm; goat, meat at 0.05 ppm; goat, meat byproducts at 0.1 ppm; hog, fat at 0.05 ppm; hog, kidney at 0.5 ppm; hog, meat at 0.05 ppm; hog, meat byproducts at 0.1 ppm; horse, fat at 0.05 ppm; horse, kidney at 0.5 ppm; horse, meat at 0.05 ppm; horse, meat byproducts at 0.1 ppm; sheep, fat at 0.05 ppm; sheep, kidney at 0.5 ppm; sheep, meat at 0.05 ppm; sheep, meat byproducts at 0.1 ppm; wheat, forage at 10.0 ppm; wheat, grain at 1.0 ppm; wheat, hay at 2.0 ppm; wheat, straw at 0.50 ppm (PP 0F6095); and 40 CFR 180.527(d) by establishing permanent tolerances for indirect or inadvertent residues of the herbicide flufenacet; N-(4-fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl]oxy]acetamide and metabolites containing the 4-fluoro-N-methylethyl benzenamine moiety in or on the following raw agricultural commodities from the application of this herbicide to the raw agricultural commodities listed in 40 CFR 180.527(a): alfalfa, forage at 0.1 ppm; alfalfa, hay at 0.1 ppm; alfalfa, seed at 0.1 ppm; clover, forage at 0.1 ppm; clover, hay at 0.1 ppm; grain, cereal, group 15, except rice at 0.4 ppm; grain, cereal, forage, fodder and straw, group 16, except rice, forage at 10.0 ppm; grain, cereal, forage, fodder and straw, group 16, except rice, stover at 3.0 ppm; grain, cereal, forage, fodder, and straw, group 16, except rice, straw at 1.0 ppm; grass, forage, fodder, and hay, group 17 at 0.1 ppm (PP 6F4631).

A. Residue Chemistry

1. Plant metabolism. The nature of the residue in field corn, soybean, rotational crops and livestock is adequately understood. The residues of concern for the tolerance expression are flufenacet parent and its metabolites containing the 4-fluoro-N-methylethyl benzenamine moiety. Based on the results of animal metabolism studies, it is unlikely that secondary residues would occur in animal commodities from the use of flufenacet on field corn and soybean.

2. Analytical method. An adequate analytical method, gas chromatography/mass spectrometry with selected ion monitoring, is available for enforcement purposes. Because of the long lead time from establishing these tolerances to publication of the enforcement methodology in the Pesticide Analytical Manual, Vol. II, the analytical methodology is being made available in the interim to anyone interested in pesticide enforcement when requested from: Calvin Furlow, Public Information and Records Integrity Branch, Information Resources and Services Division (7502C), Office of Pesticide Programs, Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. Office location and telephone number: Room 119E, CM #2, 1921 Jefferson Davis Highway, Arlington, VA 22202, [phone]).

3. Magnitude of residues. Field residue trials were conducted across the major regions of corn and soybean production in the United States. In both cases, the treatment regime was selected to represent the use patterns that are most likely to result in the highest residue and used a 60% dry flowable formulation of the active ingredient. In all cases, the test plots received a single application of the product at a rate of 0.9 lbs. of active ingredient per acre.

For corn, flufenacet was applied at preplant soil incorporated, preemergence broadcast, and early postemergence application timings. The highest average field trial residues in corn raw agricultural commodities were 0.36 ppm in forage, 0.16 ppm in fodder, and less than 0.05 ppm in grain. No significant concentration of these residues occurred when the corn grain was processed by either wet or dry milling procedures.

For soybean, flufenacet was applied as a preplant broadcast treatment that was incorporated to a depth of approximately 2 inches or as a preemergent broadcast treatment made within 1 day of planting the soybean crop. The maximum residues detected were 0.10 ppm in seed, 1.20 ppm in green forage, and 9.75 ppm in dry hay.

B. Toxicological Profile

1. Acute toxicity. i. Technical grade flufenacet has a low to moderate order of toxicity in rats by the oral route of exposure. The acute oral LD₅₀ was 1,617 milligrams/kilogram (mg/kg) for males and 589 mg/kg for females.

ii. A dermal toxicity study on technical grade flufenacet revealed low acute toxicity to rats. The dermal LD₅₀ for both sexes was >2,000 mg/kg, the highest dose tested.

iii. An acute inhalation study on technical grade flufenacet showed low toxicity in rats with a 4-hour liquid aerosol LC₅₀ for males and females of >3,740 mg/m³ air, the highest concentration tested.

iv. An eye irritation study on technical grade flufenacet in rabbits showed minimal irritation to the conjunctiva completely reversible within 7 days.

v. A dermal irritation study on technical grade flufenacet in rabbits did not produced any irritation.

vi. Skin sensitization studies on technical grade flufenacet in guinea pigs have produced equivocal results. A skin sensitization potential was exhibited under the conditions of a maximization test, whereby, there was no skin sensitization potential when tested by the Buehler Topical Closed Patch Technique.

2. Genotoxicty. Flufenacet was negative for mutagenic/genotoxic effects in a gene mutation/in vitro assay in bacteria, a gene mutation/in vitro assay in Chinese hamster lung fibroblasts cells, a cytogenetics/in vitro assay in Chinese hamster ovary cells, a cytogenetics/in vivo mouse micronucleus assay, and an in vitro unscheduled DNA synthesis assay in primary rat hepatocytes.

3. Reproductive and developmental toxicity. i. A two-generation rat reproduction study with a parental systemic no observed adverse effect level (NOAEL) of 20 ppm (1.4 mg/kg/day in males and 1.5 mg/kg/day in females) and a reproductive NOAEL of 20 ppm (1.3 mg/kg/day) and a parental systemic lowest observed adverse effect level (LOAEL) of 100 ppm (7.4 mg/kg/day in males and 8.2 mg/kg/day in females) based on increased liver weight in F₁ females and hepatocytomegaly in F₁ males and a reproductive LOAEL of 100 ppm (6.9 mg/kg/day) based on increased pup death in early lactation (including cannibalism) for F₁ litters and the same effects in both F₁ and F₂ pups at the high dose level of 500 ppm (37.2 mg/kg/day in F₁ males and 41.5 mg/kg/day in F₁ females, respectively).

ii. A rat developmental study with a maternal NOAEL of 25 mg/kg/day and with a maternal LOAEL of 125 mg/kg/day based on decreased body weight gain initially and a developmental NOEL of 25 mg/kg/day and a developmental LOAEL of 125 mg/kg/day based on decreased fetal body weight, delayed development (mainly delays in ossification in the skull, vertebrae, sternebrae, and appendages), and an increase in the incidence of extra ribs.

iii. A rabbit developmental study with a maternal NOAEL of 5 mg/kg/day and a maternal LOAEL of 25 mg/kg/day based on histopathological finds in the liver and a developmental NOAEL of 25 mg/kg/day and a developmental LOAEL of 125 mg/kg/day based on increased skeletal variations.

4. Subchronic toxicity. i. A 84-day rat feeding study with a NOAEL less than 100 ppm (6.0 mg/kg/day) for males and a NOAEL of 100 ppm (7.2 mg/kg/day) for females and with a LOAEL of 100 ppm (6.8 mg/kg/day) for males based on suppression of thyroxine (T4) level and a LOAEL of 400 ppm (28.8 mg/kg/day) for females based on hematology and clinical chemistry findings.

ii. A 13-week mouse feeding study with a NOAEL of 100 ppm (18.2 mg/kg/day for males and 24.5 mg/kg/day for females) and a LOAEL of 400 ppm (64.2 mg/kg/day for males and 91.3 mg/kg/day for females) based on histopathology of the liver, spleen and thyroid.

iii. A 13-week dog dietary study with a NOAEL of 50 ppm (1.70 mg/kg/day for males and 1.67 mg/kg/day for females) and a LOAEL of 200 ppm (6.90 mg/kg/day for males and 7.20 mg/kg/day for females) based on evidence that the bio-transformation capacity of the liver has been exceeded, (as indicated by an increase in LDH, liver weight, ALK and hepatomegaly), globulin and spleen pigment in females, decreased T4 and ALT values in both sexes, decreased albumin in males, and decreased serum glucose in females.

iv. A 21-day rabbit dermal study with the dermal irritation NOAEL of 1,000 mg/kg/day for males and females and a systemic NOAEL of 20 mg/kg/day for males and 150 mg/kg/day for females and a systemic LOAEL of 150 mg/kg/day for males and 1,000 mg/kg/day for females based on clinical chemistry data (decreased T4 and FT4 levels in both sexes) and centrilobular hepatocytomegaly in females.

5. Chronic toxicity. i. A 1-year dog chronic feeding study with a NOAEL was 40 ppm (1.29 mg/kg/day in males and 1.14 mg/kg/day in females) and a LOAEL of 800 ppm (27.75 mg/kg/day in males and 26.82 mg/kg/day in females) based on increased alkaline phosphatase, kidney, and liver weight in both sexes, increased cholesterol in males, decreased T2, T4 and ALT values in both sexes, and increased incidences of microscopic lesions in the brain, eye, kidney, spinal cord, sciatic nerve and liver.

ii. A rat chronic feeding/carcinogenicity study with a NOAEL less than 25 ppm (1.2 mg/kg/day in males and 1.5 mg/kg/day in females) and a LOAEL of 25 ppm (1.2 mg/kg/day in males and 1.5 mg/kg/day in females) based on methemoglobinemia and multi-organ effects in blood, kidney, spleen, heart, and uterus. Under experimental conditions the treatment did not alter the spontaneous tumor profile.

iii. In a mouse carcinogenicity study the NOAEL was less than 50 ppm (7.4 mg/kg/day) for males and the NOAEL was 50 ppm (9.4 mg/kg/day) for females and the LOAEL was 50 ppm (7.4 mg/kg/day) for males and the LOAEL was 200 ppm (38.4 mg/kg/day) for females based on cataract incidence and severity. There was no evidence of carcinogenicity for flufenacet in this study.

6. Animal metabolism. A rat metabolism study showed that radio-labeled flufenacet was rapidly absorbed and metabolized by both sexes. Urine was the major route of excretion at all dose levels and smaller amounts were excreted via the feces.

7. Metabolite toxicology. A 55-day dog study with subcutaneous administration of thiadone (flufenacet metabolite) supports the hypothesis that limitations in glutathione interdependent pathways and antioxidant stress result in metabolic lesions in the brain and heart following flufenacet exposure.

8. Endocrine disruption. EPA is required to develop a screening program to determine whether certain substances (including all pesticides and inerts) may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or such other effect. The Agency is currently working with interested stakeholders, including other government agencies, public interest groups, industry and research scientists in developing a screening and testing program and a priority setting scheme to implement this program. Congress has allowed 3 years from the passage of FQPA (August 3, 1999) to implement this program. At that time, EPA may require further testing of this active ingredient and end use products for endocrine disrupter effects. Based on the toxicological findings for flufenacet relating to endocrine disruption effects, flufenacet should be considered as a candidate for evaluation as an endocrine disrupter when the criteria are established.

9. Other studies. i. An acute rat neurotoxicity study with a NOAEL less than 75 mg/kg/day and a LOAEL of 75 mg/kg/day based on decreased motor activity in males.

ii. A rat subchronic neurotoxicity study with a NOAEL of 120 ppm (7.3 mg/kg/day in males and 8.4 mg/kg/day in females) and a LOAEL of 600 (38.1 mg/kg/day in males and 42.6 mg/kg/day in females) based on microscopic lesions in the cerebellum/medulla and spinal cords.

iii. A rat developmental neurotoxicity dietary study established an overall NOAEL for both dams and offspring of 17.5 ppm. A LOAEL of 80.8 ppm was established based on body weight and feed consumption declines common to both dams and offspring as well as developmental delays which were noted in the offspring (eye opening, preputial separation). No evidence of specific neurobehavioral effects in the offspring were observed at dietary concentrations of up to 404 ppm.

C. Aggregate Exposure

1. Dietary exposure. Flufenacet is an herbicide with currently registered uses on corn and soybean. Section 18 emergency exemptions for use on wheat have been approved in several states. Also, time limited tolerances exist for inadvertent or indirect residues on alfalfa, clover, and crop groups 15, 16 and 17. Tolerances are proposed for use on Crop Group 1C, tuberous and corm vegetables, which includes potatoes and sweet potatoes. There are no residential uses for flufenacet, therefore aggregate exposure would consist of any potential exposure to flufenacet residues in the registered and proposed crops and in drinking water.

i. Food. Acute and Chronic dietary exposure assessments were conducted using the Dietary Exposure Evaluation Model (DEEM®, Version 7.76) from Exponent, Inc. and the 1994-1996, 1998 CSFII consumption database. Dietary exposure values were compared to the acute RfD of 0.083 milligrams/kilogram of body weight per day (mg/kg bw/day) based on a LOEL from an acute neurotoxicity study in rats and a 900-fold uncertainty factor. The chronic RfD of 0.004 mg/kg bw/day is based on a LOEL from a combined chronic toxicity/carcinogenicity study in the rat with a 300-fold uncertainty factor.

The refined acute and chronic dietary risk assessments were performed using anticipated residues for all registered and proposed crops and crop groups. Adjustments were made to account for percent of crop treated and processing factors where available. The Tier 2 acute analysis resulted in the U.S. population using 0.00437 mg/kg bw/day or 5.2% of the acute RfD. The highest exposed subpopulation was non-nursing infants at 0.00893 mg/kg bw/day utilized or 10.7% of the acute RfD.

For the Tier 3 chronic analysis the U.S. population utilized 0.000087 mg/kg bw/day or 2.2% of the chronic RfD. The highest exposed subpopulation was children 1-6 at 0.000179 mg/kg bw/day or 4.5% of the chronic RfD.

ii. Drinking water. The EPA has calculated drinking water level of comparison (DWLOCs) for acute exposure to flufenacet in drinking water as 2.87 ppm for the U.S. population and 813 ppb for children (1-6 years old). The Agency's screening concentration in ground water (SCI-Grow) model estimates peak levels of flufenacet and its metabolite thiadone in groundwater to be 15.3 ppb. EPA's Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS) estimates peak levels of flufenacet and its metabolite thiadone in surface water to be 17 ppb. EPA's acute drinking water levels of comparison are well above the estimated exposures for flufenacet in water for the U.S. population and the subgroup with highest estimated exposure.

The EPA has calculated the drinking water level of comparison for chronic exposure to flufenacet in drinking water as 136 ppb for the U.S. population assuming that an adult weighs 70 kg and consumes a maximum of 2 liters of water per day. For children (1-6 years old), the DWLOC was 37.7 ppb assuming that a child weighs 10 kg and consumes a maximum of 1 liter of water per day. The drinking water estimated concentration (DWECs) for groundwater (parent flufenacet and degradate thiadone) calculated from modeling data is 0.03 ppb for chronic concentrations which does not exceed the DWLOC of 37.7 ppb for children (1-6 years old). The DWEC for surface water based on the computer models PRZM 2.3 and EXAMS 2.97.5 was calculated to be 14.2 ppb for chronic concentration (parent flufenacet and degradate thiadone) which does not exceed the DWLOC of 37.7 ppb for children (1-6 years old). The EPA has concluded that there is a reasonable certainty that no harm will result from aggregate exposure to flufenacet residues.

2. Non-dietary exposure. There are no non-food uses of flufenacet currently registered under the Federal Insecticide, Fungicide and Rodenticide Act, as amended. No non-dietary exposures are expected for the general population.

D. Cumulative Effects

Flufenacet is structurally a thiadiazole. EPA is not aware of any other pesticides with this structure. For flufenacet, EPA has not yet conducted a detailed review of common mechanisms to determine whether it is appropriate, or how to include this chemical in a cumulative risk assessment. After EPA develops a methodology to address common mechanism of toxicity issues to risk assessments, the Agency will develop a process (either as part of the periodic review of pesticides or otherwise) to reexamine these tolerance decisions. Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, flufenacet does not appear to produce a toxic metabolite produced by other substances. For the purposes of these tolerance actions; therefore, EPA has not assumed that flufenacet has a common mechanism of toxicity with other substances.

E. Safety Determination

1. U.S. population. Using the assumptions and data described above, it is concluded that chronic dietary exposure to all registered and proposed uses of flufenacet will utilize at most 2.2% of the chronic RfD for the U.S. population. The acute dietary exposure assessment results in the U.S. population utilizing 5.2% of the acute RfD. EPA generally has no concern for exposures below 100% of the acute or chronic reference dose. Drinking water levels of comparison based on the dietary exposure are greater than the highly conservative drinking water estimated concentrations as shown above. Therefore, there is a reasonable certainty that no harm will occur to the U.S. population from aggregate exposure (food and drinking water) to residues of flufenacet.

2. Infants and children. In assessing the potential for additional sensitivity of infants and children to residues of flufenacet, EPA considered data from developmental toxicity studies in the rat and rabbit and a two-generation reproduction study in the rat. The developmental toxicity studies are designed to evaluate adverse effects on the developing organism resulting from pesticide exposure during prenatal development to one or both parents. Reproduction studies provide information relating to effects from exposure to the pesticide on the reproductive capability of mating animals and data on systemic toxicity. FFDCA section 408 provides that EPA shall apply an additional tenfold margin of safety for infants and children in the case of threshold effects to account for pre- and post-natal toxicity and the completeness of the data base unless EPA determines that a different margin of safety will be safe for infants and children. Although there is no indication of increased sensitivity to young rats or rabbits following pre- and/or post-natal exposure to flufenacet in the standard developmental and reproductive toxicity studies, an additional developmental neurotoxicity study, which is not normally required, is needed to access the susceptibility of the offspring in function/neurological development. Therefore, EPA has required that a developmental neurotoxicity study be conducted with flufenacet and a threefold safety factor for children and infants will be used in the aggregate dietary acute and chronic risk assessment. Although there is no indication of additional sensitivity to young rats or rabbits following pre- and/or post-natal exposure to flufenacet in the developmental and reproductive toxicity studies; the Agency concluded that the FQPA safety factor should not be removed but instead reduced because:

i. There was no assessment of susceptibility of the offspring in functional/neurological developmental and reproductive studies.

ii. There is evidence of neurotoxicity in mice, rats, and dogs.

iii. There is concern for thyroid hormone disruption.

Using the assumptions and data described in the aggregate exposure section and the appropriate safety factors as discussed above it is concluded that the most sensitive subpopulations of infants and children have a reasonable certainty of no harm. For the chronic assessment, the most sensitive subpopulation, children 1-6, uses 4.5% of the chronic RfD. The acute assessment shows the most sensitive subpopulation to be non-nursing infants at 10.7% of the acute RfD. The calculated drinking water levels of comparison (DWLOCs) for children of 765 ppb (acute) and 38 ppb (chronic) are well above the conservative drinking water estimated concentrations. Therefore, there is a reasonable certainty that no harm will occur to infants and children from aggregate exposure to potential residues of flufenacet in food and drinking water.

F. International Tolerances

Maximum residue levels are established or proposed for countries of the European Communities in the following commodities: Cereals at 0.5 ppm; corn at 0.5 ppm; potato at 0.1 ppm; sunflower at 0.05 ppm; soybean at 0.05 ppm; animal meat at 0.05 ppm; animal edible offal's at 0.05 ppm; animal fat at 0.05 ppm; milk at 0.01 ppm; and eggs at 0.05 ppm.