FLUORIDE ACTION NETWORK PESTICIDE PROJECT
Return to FAN's Pesticide Homepage
Return to Trifluralin Index Page
Trifluralin. November 24, 2004. Proposed pesticide tolerance for residues of trifluralin in mint oil at 2.0 ppm. Federal Register.
Docket identification (ID) number OPP-2004-0142
Note from FAN: US EPA documents released with this Notice:
• August 30, 2004 - Trifluralin Risk Assessment Overview (10 pages)
• May 7, 2004 - Trifluralin: Human Health Risk Assessment (55 pages)
• October 2, 2003 - Toxicology Disciplinary Chapter for the Tolerance Reassessment Eligibility Decision Document Trifluralin (PC Code: 036101) (66 pages)
• August 31, 2004 - Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment Progress and Risk Management Decision (TRED) for Trifluralin (3 pages)
• Sept 21, 2004 - Clarification of the Trifluralin Drinking Water Assessment for the HED Tolerance Reassessment and Characterization on Relative Differences for USGS NAWQA Ground Water Monitoring Data and Its Comparison to SCI-GROW Model Predictions as presented in the NRDC objection (Imidacloprid FR) and the trifluralin TRED (D308490) (2 pages)
• May 12, 2004 - Review of "Dissipation of Transferable Residues of Benefin and Trifluralin on Turf Treated with a Formulation of the Pesticides" (15 pages)
• May 2, 2003 - Report of the Hazard Identification Assessment Review Committee - Trifluralin (P.C. Code 036101) - (32 pages)
• May 5, 2004 - Residential Exposure Assessment and Recommendations for the Tolerance Reassessment Evaluation Decision (TRED) Document for Trifluralin (50 pages)
• March 8, 2004 - Trifluralin. Anticipated Residues, Acute, Probabilistic, Chronic and Cancer Dietary Exposure Assessments for the Reregistration Eligibility Decision (68 pages)
• March 9, 2004 - Trifluralin: Health Effects Division (HED) Metabolism Assessment Review Committee (MARC) Decision Document. Meeting Date: 4 February 2004. PC Code: 036101 (4 pages)
• March 4, 2004 - Trifluralin: Residue Chemistry Chapter for the Tolerance Reassessment Evaluation Decision (TRED) Document (75 pages)
• Dec 3, 2003 - Trifluralin - Drinking Water Assessment for Tolerance Reassessment Eligibility Decision (PC Code: 036101; DP Barcode: D296624 (109 pages)
• March 9, 2004 - Review of Trifluralin Incident Reports DP Barcode D300064, Chemical# 036101 (11 pages)[Federal Register: November 24, 2004 (Volume 69, Number 226)]
[Proposed Rules]
[Page 68287-68299]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24no04-24]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-2004-0142; FRL-7686-4]
Trifluralin; Proposed Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: This document proposes to establish a tolerance for residues
of trifluralin in mint oil under the Federal Food, Drug, and Cosmetic
Act (FFDCA), as amended by the Food Quality Protection Act of 1996
(FQPA). The amendment substantially rewrote section 408 of FFDCA. As a
result, the revisions made it necessary, once again, to establish
tolerances on certain commodities, such as mint oils, that had
previously been deemed unnecessary.
DATES: Comments must be received on or before January 24, 2005.
ADDRESSES: Submit your comments, identified by docket identification
(ID) number OPP-2004-0142, by one of the following methods:
• Federal eRulemaking Portal: http://www.regulations.gov/.
Follow the on-line instructions for submitting comments.
• Agency Website: http://www.epa.gov/edocket/. EDOCKET,
EPA's electronic public docket and comment system, is EPA's preferred
method for receiving comments. Follow the on-line instructions for
submitting comments.
• E-mail: Comments may be sent by e-mail to opp-docket@epa.gov,
[[Page 68288]]
Attention: Docket ID Number OPP-2004-0142.
• Mail: 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-2004-0142.
• Hand Delivery: Public Information and Records Integrity
Branch (PIRIB), Office of Pesticide Programs (OPP), Environmental
Protection Agency, Rm. 119, Crystal Mall #2, 1801 S. Bell St.,
Arlington, VA, Attention: Docket ID Number OPP-2004-0142. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
Instructions: Direct your comments to docket ID number OPP-2004-
0142. EPA's policy is that all comments received will be included in
the public docket without change and may be made available online at
http://www.epa.gov/edocket/, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through EDOCKET,
regulations.gov, or e-mail. The EPA EDOCKET and the regulations.gov
websites are ``anonymous access'' systems, which means EPA will not
know your identity or contact information unless you provide it in the
body of your comment. If you send an e-mail comment directly to EPA
without going through EDOCKET or regulations.gov, your e-mail address
will be automatically captured and included as part of the comment that
is placed in the public docket and made available on the Internet. If
you submit an electronic comment, EPA recommends that you include your
name and other contact information in the body of your comment and with
any disk or CD ROM you submit. 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. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit EDOCKET on-line or see the Federal Register of May 31,
2002 (67 FR 38102) (FRL-7181-7).
Docket: All documents in the docket are listed in the EDOCKET index
at http://www.epa.gov/edocket/. Although listed in the index, some
information is not publicly available, i.e., 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 either electronically in EDOCKET or in hard
copy at the Public Information and Records Integrity Branch (PIRIB),
Rm. 119, Crystal Mall #2, 1801 S. Bell St., 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 (703)
305-5805.
FOR FURTHER INFORMATION CONTACT: John W. Pates, Jr., Reregistration
Division (7508C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 308-8195; e-mail address:
pates.john@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
You may be potentially affected by this action if you are a
professional applicator, commercial applicator, residential applicator,
agricultural worker, and/or a non-residential user. Potentially
affected 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 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. To determine
whether you or your business may be affected by this action, you should
carefully examine the applicability provisions in Unit II. If you have
any questions regarding the applicability of this action to a
particular entity, consult the person listed under FOR FURTHER
INFORMATION CONTACT.
B. How Can I Access Electronic Copies of this Document and Other
Related Information?
In addition to using EDOCKET (http://www.epa.gov/edocket/), you may
access this Federal Register document electronically through the EPA
Internet under the ``Federal Register'' listings at http://www.epa.gov/
fedrgstr/. A frequently updated electronic version of 40 CFR part 180
is available on E-CFR Beta Site Two at http://www.gpoaccess.gov/ecfr/.C. What Should I Consider as I Prepare My Comments for EPA?
1. Submitting CBI. Do not submit this information to EPA through
EDOCKET, regulations.gov, or e-mail. Clearly mark the part or all of
the information that you claim to be CBI. For CBI information in a disk
or CD ROM that you mail to EPA, 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 claimed as CBI. In addition to one
complete version of the comment that includes 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.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for preparing your comments. When submitting comments,
remember to:
i. Identify the rulemaking by docket ID number and other
identifying information (subject heading, Federal Register date, and
page number).
ii. Follow directions. The Agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
iii. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
iv. Describe any assumptions and provide any technical information
and/or data that you used.
v. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
vi. Provide specific examples to illustrate your concerns, and
suggest alternatives.
vii. Explain your views as clearly as possible, avoiding the use
of profanity or personal threats.
viii. Make sure to submit your comments by the comment period
deadline identified.II. Background and Statutory Findings
EPA on its own initiative, under section 408(e) of FFDCA, 21 U.S.C.
346a(e), is proposing to establish a permanent tolerance for residues
of the herbicide trifluralin in mint oil at 2.0 parts per million (ppm).[[Page 68289]]
Tolerances under section 408 of FFDCA for trifluralin in or on
peppermint tops and spearmint tops are established in 40 CFR 180.207 at
0.05 ppm. Previously, under section 409 of FFDCA, tolerances were
established for trifluralin in peppermint oil and spearmint oil at 2.0
ppm. In 1996, these section 409 of FFDCA tolerance regulations were
revoked as unnecessary. Shortly thereafter, the FFDCA was amended by
FQPA. This amendment substantially rewrote section 408 of FFDCA and
consolidated, for the most part, the authority addressing pesticide
residues in food under section 408 of FFDCA. The revisions to section
408 of FFDCA also made it necessary, once again, to establish
tolerances on certain commodities, such as mint oils, that had
previously been deemed unnecessary.The Agency has completed the human health risk assessment for
trifluralin and is now proposing to establish a permanent tolerance at
2.0 ppm for mint oil. Also, all existing tolerances are being
maintained at current levels and are considered to be reassessed by the
Trifluralin Tolerance Reassessment Eligibility Decision (TRED) signed
on August 31, 2004.Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a
reasonable certainty that no harm will result from aggregate exposure
to the pesticide chemical residue, including all anticipated dietary
exposures and all other exposures for which there is reliable
information.'' This includes exposure through drinking water and in
residential settings, but does not include occupational exposure.
Section 408(b)(2)(C) of FFDCA requires EPA to give special
consideration to exposure of infants and children to the pesticide
chemical residue in establishing a tolerance and to ``ensure that there
is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to the pesticide chemical residue....''.
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 of FFDCA and a complete
description of the risk assessment process, see the final rule on
Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997) (FRL-
5754-7).III. Aggregate Risk Assessment and Determination of Safety
Consistent with 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, consistent with section
408(b)(2) of FFDCA, for a tolerance for residues of trifluralin in mint
oil at 2.0 ppm. EPA's assessment of exposures and risks associated with
establishing the tolerance follows:A. Toxicological Profile
EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by trifluralin are
discussed in Table 1 of this unit as well as the no-observed-adverse-
effect-level (NOAEL) and the lowest-observed-adverse-effect-level
(LOAEL) from the toxicity studies reviewed.
Table 1.--Subchronic, Chronic, and Other Toxicity Tables Guideline No./Study Type MRID No. (year)/
Classification/ DosesResults/Comments 870.3100
2-Week R-F Feeding--Rats (male).00157154 (1983)
0; 6,500 ppm range-finding study for 00157156 (1985), 41038301 (1986).
Acceptable/ Nonguideline.NOAEL = Not achieved
LOAEL = 6,500 ppm based on renal epithelial damage, urine triple phosphates crystals and urinary sediment870.3100
90-Day Oral toxicity--Rat....00151906 (1980)
0; 800; 2,000; or 5,000 ppm. M: 0, 59, 154, and 392 milligram/ kilogram/day (mg/kg/day). F: 0, 69, 168, and 421 mg/kg/ day.
Acceptable/ Guideline.NOAEL = 2,000 ppm (154/168 mg/kg/day, Male/ Female (M/F))
LOAEL = 5,000 (392/421(mg/kg/day), M/F)
Based on minor decreases in overall body weight gains and food consumption in males and females, decreased hemoglobin, alkaline phosphatase, and alanine aminotransferase in the males, and increased absolute and relative (to body) liver weights in males and females870.3200
21/28-Day dermal toxicity-- Rabbit.41993810 (1991)
0, 100, 500, or 1,000 mg/kg/ day (formulation containing 35.8% trifluralin and 2.6% XRD- 498). Acceptable/ Guideline.Systemic NOAEL =1,000 mg/kg/day
Systemic LOAEL = Not achieved
Dermal NOAEL = Not achieved
Dermal LOAEL = 100 mg/kg/ day, edema, and/or scaling and fissuring 100 mg/kg/day based skin irritation870.3200
31-Day dermal toxicity--Rat..00153171 (1982)
0; 40; 200; or 1,000 mg/kg/ day.
Acceptable/ Guideline.Systemic NOAEL = 1,000 mg/kg/day (limit dose)
Systemic LOAEL = Not achieved
Dermal NOAEL = 40 mg/kg/day
Dermal LOAEL = 200 mg/kg/day based on sub-epidermal inflamation and ulcerations in males and females[[Page 68290]] 870.3200
21/28-Day dermal toxicity-- Rat.00152888 (1985)
0; 1,000 mg/kg/day (limit dose).
Acceptable/ Guideline.Systemic NOAEL = 1,000 mg/kg/day
Systemic LOAEL = Not achieved
Dermal NOAEL= Not achieved
Dermal LOAEL = 1,000 mg/kg/day (limit dose) based on erythema, edema, and desquamination of the treated skin870.3465
30-Day inhalation toxicity...40392312 (1987)
reformat of 00151904 (1982)
0; 100; 301; 1,006 mg/ m\3\(6 hours/ day 5 days/ week for up to 30 days).
Acceptable/ Nonguideline.NOAEL = 301 mg/m\3\
LOAEL = 1,006 mg/m\3\
based on increased bilirubin in females and incidences of dyspnea and ruffled fur in males and females870.3700
Developmental Toxicity Study-- Rat.00151899 (1983), 159620 (1986), 40392310 (1987)
0, 20, 100, 500 mg/kg/day.Systemic Maternal NOAEL = 100 mg/kg/day
Systemic Maternal LOAEL = 500 mg/kg/day based
on mortality, clinical signs, decreased body weight gains, decreased food consumption, and increased liver and spleen weights
Developmental NOAEL =100 mg/kg/day
Developmental LOAEL = 500 mg/kg/day based on reduced ossification of the vertebrae and ribs and thickened, wavy or bent ribs and increased incidences of resorptions870.3700
Developmental Toxicity Study-- Rat.00152419 (1984)
0; 100; 225; 470; or 1,000 mg/kg/day.
Acceptable/ Guideline.
Maternal NOAEL = 475 mg/ kg/day
Maternal LOAEL = 1,000 mg/kg/day based on decreased body weights and decreased food consumption
Offspring NOAEL = 475 mg/ kg/day
Offspring LOAEL = 1,000 mg/kg/day based on decreased fetal body weights
Developmental NOAEL = 1,000 mg/kg/day
Developmental LOAEL was not established870.3700
Developmental Toxicity-- Rabbit.00152421 (1984)
0, 100, 225, 500 mg/kg/day.
Acceptable/ Guideline.Maternal NOAEL = 100 mg/ kg/day
Maternal LOAEL = 225 mg/ kg/day based on abortions, macroscopic changes in the liver and lungs, and decreased food consumption
Developmental NOAEL = 100 mg/kg/day
Developmental LOAEL = 225 mg/kg based on abortions870.3800
2-Generation reproduction-- Rat.00151901 (1984)
00151902 (1984)
Feed analysis.
00151903 (1984)
Path.
0; 200; 650; 2,000 ppm.
0, 20, 32.5, 200 mg/kg/day (1 ppm = 0.5 mg/kg/day).
Acceptable/ Guideline.Parental NOAEL = 200 ppm (10 mg/kg/day)
Parental LOAEL = 650 ppm (32.5 mg/kg/day) based on mortality due to acute renal failure and increased lesions of the renal proximal tubules in the F1 females; increased relative (to body) weights of the liver, kidney (males), and testes in both generations
Offspring NOAEL = 200 ppm (10 mg/kg/day)
Offspring LOAEL = 650 ppm (32.5 mg/kg/day) based on decreased pup weights in both generations and increased relative to body liver weights in the F2b females
Repro NOAEL = 2,000 ppm (100 mg/kg/day)
Repro LOAEL = Not established870.3800
2-Generation reproduction-- Rat.00162543 (1986),
44135107 (1996)
0; 200; 630; 2,000 ppm.
0, 15, 47, 148 mg/kg/day.
Acceptable/ Guideline.Parental NOAEL = 200 ppn (15 mg/kg/day)
Parental LOAEL = 630 ppm (47 mg/kg/day) based on decreased body weight gains (BWG) and food consumption
Offspring NOAEL = 200 ppm (15 mg/kg/day)
Offspring LOAEL = 630 ppm (47 mg/kg/day) based on small pup size in 3 litters
Reproductive NOAEL = 2,000 ppm (148 mg/kg/ day)
Reproductive LOAEL = Not established870.3800
2-Generation reproduction-- Rat.40405007 (1987)
0; 50; 450; 4,000 ppm.
M: 0, 3.9, 35, 295 mg/kg/day.
F: 0, 4.7, 42, 337 mg/kg/day.
Acceptable/ Guideline.Parental NOAEL = 450 ppm (35/42 mg/kg/day M/F)
Parental LOAEL = 4,000 ppm (295/337 mg/kg/day M/F) based on decreased body weights, body weight gains, food consumption, and food efficiency in males and females of both generations; decreased ovary weights in both generations; colon distension in the F1 males; and uterine atrophy in the females of both generations
Offspring NOAEL = 450 ppm (35/42 mg/kg/day M/F)
Offspring LOAEL = 4,000 ppm (295/337mg/kg/day, M/F) based on decreased pup weight in F1a litters
Reproductive NOAEL = 450 ppm (35/42 mg/kg/day)
Reproductive LOAEL = 4,000 ppm (295/337 mg/kg/day M/F) based on decreased fetal, neonatal, and litter viability and decreased lactation index in the F1a pups; and decreased number of implantation sites, newborn pups, litter size, and pup weights in both generations[[Page 68291]] 870.4100
1-Year Oral (capsule) Study-- Dog.00151908 (1984),
00159618 (1985)
0, 30, 150, or 750 ppm.
0.0, 0.8, 3.8, 18.8 mg/kg /day.
Acceptable/ Guideline.NOAEL = 30 ppm (0.8 mg/ kg/day)
LOAEL = 150 ppm (3.8 mg/ kg/day) based on increased absolute liver weights in males870.4100
1-Year Oral (capsule) Study-- Dog.42447001 (1992)
0, 0.75, 2.4, 40 mg/kg/day.
Acceptable/ Guideline.Systemic NOAEL = 2.4 mg/ kg/day
Systemic LOAEL = 40 mg/ kg/day, based on increased frequency of abnormal stool and pigment deposition in the kidney and liver in males and females, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in males870.4300
24-Month Chronic Toxicity/ Carcinogenicity Study--Rat.00162457 (1985),
00162458 (1985)
0; 200; 800; or 3,200 ppm.
M: 0, 10, 40, and 169 mg/kg/ day.
F: 0, 13, 53, and 219 mg/kg/day.
Acceptable/ Guideline.NOAEL = 800 ppm (40/53 mg/kg/day M/F)
LOAEL = 3,200 ppm (169/ 219 mg/kg/day M/F) based on decreases in body weight and body weight gains
At the doses tested, the carcinogenic potential of trifluralin was negative. Dosing was considered adequate based on differences in body weight and bodyweight gains.870.4300
24- Month Carcinogenicity Study--Mouse.00158935 (1986),
40392313 (1987)
0, 50, 200, or 800 ppm.
M: 0, 7.5, 29, and 118 mg/kg/ day.
F: 0, 10.5, 41, and 165 mg/kg/ day.
Unacceptable/ Guideline.Sys NOAEL = 800 ppm (118/ 165 mg/kg/day in males/ females); highest dose tested
System LOAEL = Not achieved
NOAEL for the range finder was 2500 ppm (375 mg/kg/day), the highest dose tested
870.5100
Bacterial Reverse Gene Mutation Assay.MRID 00148345 (1984)
Acceptable/ Guideline.There was no evidence of induced mutant colonies over background. 870.5100
Bacterial Reverse Gene Mutation Assay.MRID 40334707 (1987)
Acceptable/ Guideline.There was no evidence of induced mutant colonies over background. 870.5100
Bacterial Reverse Gene Mutation Assay.MRID 00153173 (1979)
Acceptable/ Guideline.There was no evidence of induced mutant colonies over background. 870.5250
Gene Mutation Assay--Yeast...MRID 00151898 (1982)
Acceptable/ Guideline.There was no concentration-related positive response of induced mutant colonies over background. 870.5300
In vitro Mammalian Cell Gene Mutation Assay.MRID 00126661
Acceptable/ Guideline.There was no concentration-related positive response of induced mutant colonies over background. 870.5450
Dominant Lethal--Rat.........MRID 00148319 (1984)
Acceptable/ Guideline.There was no time-related positive response of increased pre- or post-implantation loss compared to controls. 870.5300
Forward Gene Mutation Assay..MRID 40765601 (1988)
Acceptable/ Guideline.There was no evidence of induced mutant colonies over background in the presence or absence of S9-activation. 870.5300
Forward Gene Mutation Assay..MRID 00148318 (1984)
Acceptable/ Guideline.There was no evidence of induced mutant colonies over background in the presence or absence of S9-activation. 870.5385
In Vivo Mammalian Cytogenetics (Bone Marrow/ Spermatogonial Aberration Test).MRID 40765603 (1988)
Acceptable/ Guideline.There was no evidence of chromosome aberration induced over background. [[Page 68292]] 870.5385
In Vivo Mammalian Cytogenetics (Bone Marrow Chromosome Aberration Test).MRID 00148320
Acceptable/ Guideline.There was no evidence of chromosome aberration induced over background. 870.5395
In Vivo Mouse Erythrocyte Micronucleus Assay.MRID 00151895 (1981)
Acceptable/ Guideline.There was no significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow compared to controls. 870.5450
Dominant Lethal--Mouse.......
MRID 00151896 (1984)
Acceptable/ Guideline.There was no time-related positive response of increased pre- or post-implantation loss compared to controls. 870.5550
Unscheduled DNA synthesis in mammalian cell culture.MRID 40765602 (1988)
Acceptable/ Guideline.There was no evidence that unscheduled DNA synthesis, as determined by radioactive tracer procedures (nuclear silver grain counts), was induced. 870.5550
Unscheduled DNA synthesis in mammalian cell culture.MRID 00151894 (1982)
Acceptable/ Guideline.There was no evidence that unscheduled DNA synthesis, as determined by liquid scintillation counting procedures, was induced. 870.5900
In Vivo Sister Chromatid Exchange Assay.MRID 00133426 (1983)
Acceptable/ Guideline.There was no evidence of SCE induced over background. 870.7845
Metabolism--Rat....... Urinary metabolites..41218901 (1989)
Acceptable/ Guideline.The objective of this study was to identify the urinary metabolites of trifluralin. There was no sex-dependent effect on metabolic
profiles. A minimum of 20-30 non-conjugated metabolites and an additional 10-20 conjugated metabolites were present in the urine, but no parent compound was detected. Information on the percentage of the administered dose excreted in the urine was not provided. However, no single metabolite accounted for more than 8-10% of the total urinary radioactivity, and the majority of the metabolites were present at 1-2% of the total urinary radioactivity. Thus, almost all of the metabolites were minor (< 5% of the total radioactive dose). Metabolite F1B was found at 8.2-8.9% of the total urinary radioactivity in both sexes, and Metabolite F2, N-[(3-(acetylamino)- 2-amino-5- (trifluoromethyl)phenyl] acetamide, was found at 4.0-5.2%. Metabolite F1B was partially characterized as retaining the trifluoromethyl groups, the two equivalent aromatic protons, and the two nitro groups, but the propyl groups were lost. Ten other metabolites were identified (< 0.1-3.7% of total urinary radioactivity, each compound in each sex). Two additional metabolites were partially characterized (0.-2.6% of total urinary radioactivity, each compound in each sex).
Four metabolic pathways were identified as follows:
i. Oxidative N-dealkylation of one or both propyl groups and metabolites which were hydroxylated on the propyl side chain.
ii. Reduction of one or both nitro groups to the corresponding amine.
iii. Cyclization reactions to give a variety of substituted and unsubstituted
benzimidazole metabolites.
iv. Conjugation reactions, including acetylation of the reduced nitro groups, sulfate, and glucuronic acid conjugates.Special study
3-Month Feeding--Rat with Urinalysis Study.00157156 (1985),
40138301(1986),
41086101 (1989)
0; 50; 200; 800; 3,200; and 6,400 ppm. 0, 2.6, 10.7, 42.2, 170.2, and 342.1 mg/ kg/day.
Acceptable/ Nonguideline.NOAEL = 200 ppm (10.7 mg/ kg/day)
LOAEL for nephrotoxicity = 800 ppm (42.2mg/kg/ day), based on the presence of cortical tubular cytoplasmic hyaline droplets; increased total protein, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) in the urine; and increased urinary volume upon protein electrophoresis and urinalysis. This study was to provide additional information to establish a NOAEL for nephrotoxicity, which was observed in a chronic feeding study in rats at the lowest dose tested.
B. Toxicological EndpointsThe dose at which no adverse effects are observed (the NOAEL) from
the toxicology study identified as appropriate for use in risk
assessment is used to estimate the toxicological level of concern
(LOC). However, the lowest dose at which adverse effects of concern are
identified (the LOAEL) is sometimes used for risk assessment if no
NOAEL was achieved in the toxicology study selected. An uncertainty
factor (UF) is applied to reflect uncertainties inherent in the
extrapolation from laboratory[[Page 68293]]
animal data to humans and in the variations in sensitivity among
members of the human population as well as other unknowns. A UF of 100
is routinely used, 10X to account for interspecies differences and 10X
for intraspecies differences.
For dietary risk assessment (other than cancer) the Agency uses the
UF to calculate an acute or chronic reference dose (acute RfD or
chronic RfD) where the RfD is equal to the NOAEL divided by the
appropriate UF (RfD = NOAEL/UF). Where an additional safety factor is
retained due to concerns unique to the FQPA, this additional factor is
applied to the RfD by dividing the RfD by such an additional factor.
The acute or chronic Population Adjusted Dose (aPAD or cPAD) is a
modification of the RfD to accommodate this type of FQPA Safety Factor
(SF).
For non-dietary risk assessments (other than cancer) the UF is used
to determine the LOC. For example, when 100 is the appropriate UF (10X
to account for interspecies differences and 10X for intraspecies
differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to
exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and
compared to the LOC.
The linear default risk methodology (Q*) is the primary method
currently used by the Agency to quantify carcinogenic risk. The Q*
approach is a conservative method which assumes that any amount of
exposure will lead to some degree of cancer risk. A Q* is calculated
and used to estimate risk which represents a probability of occurrence
of additional cancer cases (e.g., risk is expressed as 1 x
10-\6\ or one in a million). Even though the Agency does not
have a mouse study, the database is considered to be complete with the
rat data. A summary of the toxicological endpoints for trifluralin used
for human risk assessment is shown in Table 2 of this unit:
Table 2.--Toxicological Dose and Endpoints for Trifluralin Exposure scenario Dose used in risk assessment, UF Special FQPA SF* target MOE Study and toxicological effects Acute Dietary
(Females 13-50 years of age)NOAEL = 100 mg/kg/day
UF = 100
Acute RfD = 1.0 mg/kg/ day.Special FQPA SF = 1
aPAD = 1.0 mg/kg/dayDevelopmental Toxicity Study--Rat
LOAEL = 500 mg/kg/day
based on increased total litter resorptionsAcute Dietary
(General population, including infants and children).No appropriate single dose endpoint was selected. Chronic Dietary
All populationNOAEL = 2.4 mg/kg/day
UF = 100
Chronic RfD = 0.024 mg/ kg/day.Special FQPA SF = 1
cPAD = 0.024 mg/kg/day.
Chronic Toxicity (capsule)--Dog
LOAEL = 40 mg/kg/day based on based on increased frequency of abnormal stool, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in malesShort-Term Incidental Oral
(1-30 days)NOAEL = 10 mg/kg/day MOE = 100 2-Generation Reproduction Study-- Rat
LOAEL = 32.5 mg/kg/day based on decreased pup weights in both generationsIntermediate-Term Incidental Oral
(1-6 months)NOAEL = 10 mg/kg/day MOE = 100 Special Urinalysis Study-- Rat
LOAEL = 40 mg/kg/day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine; albumin [alpha]1- globulin and [alpha]2- globulin observed by urine electrophoresis; and increased urinary volumeShort-Term Dermal
(1 to 30 days)No quantification required since there was no systemic toxicity at the limit dose in the dermal toxicity study. There are no developmental toxicity concerns. The HIARC also recommends that the products containing trifluralin should be labeled as SENSITIZER. Intermediate-Term Dermal
(1 to 6 months)Oral study
NOAEL = 10 mg/kg/day...
(dermal absorption rate = 3%).Residential MOE = 100
Occupational MOE = 100.Special Urinalysis Study--Rat
LOAEL = 40mg/kg/day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine; albumin [alpha]1-globulin and [alpha]2-globulin observed by urine electrophoresis; and increased urinary volumeLong-Term Dermal
(>6 months)Oral study
NOAEL = 2.4 mg/kg/day.. (dermal absorption rate = 3% when appropriate).Residential MOE = 100
Occupational MOE = 100.Chronic Toxicity (capsule)--Dog
LOAEL = 40mg/kg/day based on based on increased frequency of abnormal stool, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in males[[Page 68294]] Short-Term Inhalation
(1 to 30 days)Inhalation study NOAEL= 81 mg/kg/day Residential MOE = 100
Occupational MOE = 100.30-Day Inhalation Study-- Rat
LOAEL = 270 mg/kg/day based on increased methemoglobin and bilirubin in females and incidences of dyspnea and ruffled fur in males and femalesIntermediate-Term Inhalation
(1 to 6 months)Oral study NOAEL = 10 mg/kg/day
(inhalation absorption rate = 100%).Residential MOE = 100
Occupational MOE = 100.Special Urinalysis Study--Rat
LOAEL = 40 mg/kg/day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine;
albumin [alpha]1-globulin and [alpha]2-globulin observed by urine electrophoresis; and increased urinary volumeLong-Term Inhalation
(>6 months)Oral studyNOAEL= 2.4 mg/ kg/day
(inhalation absorption rate = 100%).Residential MOE = 100
Occupational MOE = 100.Chronic Toxicity (capsule)--Dog
LOAEL = 40 mg/kg/day based on based on increased frequency of abnormal stool, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in malesCancer
(Oral, dermal, inhalation)Q1* = 5.8 X 10-\3\ (mg/kg/day)-\1\. The Agency concluded that trifluralin is a ``Group C'' (limited evidence of carcinogenicity) carcinogen with a Q1* of 0.0077 (mg/kg/day)-\1\; (Based on male rat thyroid follicular cell tumors combined). Recalculation of the Q1* with 1/89/21/13/27/81/163/8s interspecies scaling factor resulted in a Q1* of 0.00579 (mg/kg/day)-\1\. (No additional data needed). UF = uncertainty factor, Special FQPA SF = Special FQPA safety factor - a FQPA safety factor based on concerns unique to the FQPA, NOAL = no observed adverse effect level, LOAEL = lowest observed adverse effect level, PAD = population adjusted dose (a = acute, c = chronic) RfD = reference dose, MOE = margin of exposure, NA = Not Applicable
C. Exposure Assessment1. Dietary exposure from food and feed uses. Tolerances have been
established (40 CFR 180.207) for the residues of trifluralin, in or on
a variety of raw agricultural commodities. Dietary exposure estimates
are also factored by the estimated weighted average usage, or percent
crop treated (PCT) data. Risk assessments were conducted by EPA to
assess dietary exposures from trifluralin in food as follows:i. Acute exposure. Acute dietary 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 one day
or single exposure. The Dietary Exposure Evaluation Model (DEEM\TM\)
analysis evaluated the individual food consumption as reported by
respondents in the United States Department of Agriculture (USDA) 1994-
1996 and 1998 Nationwide Continuing Surveys of Food Intake by
Individuals (CSFII) and accumulated exposure to the chemical for each
commodity. Additionally, acute risks were also estimated using the
Lifeline model (version 2.0). Lifeline converts the raw agricultural
commodity (RAC) residues into food residues by randomly selecting a RAC
residue value from the user defined residue distribution (created from
the residue, PCT, and processing factors data), and calculating a net
residue for that food based on the ingredient's mass contribution to
that food item. The Lifeline model estimated acute exposure based on
the acute 1-day dietary dose drawn randomly from an age-specific
seasonal exposure profile of 1,000 individuals.In the course of conducting a Tier 3 dietary exposure analysis,
decisions are made regarding the following: The residue data used in
the analysis (field trials, monitoring data, etc.) refinements
incorporated in such as PCT and processing factors. Monitoring data
were used for the majority of crops whereby field trial data was used
for the remainder of the commodities. Monitoring data were translated
to similar crops when possible, generally according to the Agency's
Standard Operating Procedure (SOP) 99.3 ``Translation of Monitoring
Data.'' The following commodities used USDA Pesticide Data Program
(PDP) monitoring data: Carrots, celery, orange, peach, squash, sweet
pepper, and wheat. For PCT, the following commodities noted 100 PCT:
Apricot, apricot juice, apricots-dried, brussel sprouts, cherries,
cherries-dried, cherries-juice, chicory, eggplant, endive (escarole),
flax seed, horseradish, kohlrabi, mustard seeds, mung beans, oats,
oats-bran, parsnip, rapeseed (canola oil), and salsify. However, the
majority of PCT for all other commodities is well below 100% (e.g, mint
= 3%). For a more comprehensive listing of all commodities regarding
PCT see the Residue Chemistry Chapter for Trifluralin, which is
provided as background in EPA's public docket at http://www.epa.gov/edocket/ under docket ID number OPP-2004-0142.An acute dietary assessment was not conducted for the general U.S.
population or infants and children because there was no appropriate
single dose endpoint for this population subgroup. Trifluralin is not
acutely toxic and there is no expectation that single, or single-day
high-end exposure, including aggregate exposure, will have an adverse
effect.ii. Chronic exposure. In conducting this chronic dietary risk
assessment the Dietary Exposure Evaluation Model (DEEM\TM\) analysis
evaluated the individual food consumption as reported by respondents in
the USDA 1994-1996 and 1998 CSFII and accumulated exposure to the
chemical for each commodity. The following summarizes the Agency's
current method for determining exposure due to use on food commodities.
Chronic dietary exposure is estimated for the general U.S. population
and population subgroups defined by sex, age, region, and ethnicity.
Durations of chronic[[Page 68295]]
exposure vary from 1-year as represented by ``all infants,'' to
lifetime exposure as represented by the general U.S. population, which
combines all population subgroups to form a mean exposure value. It
should be noted that all parameters of chronic dietary exposure
estimates are averaged values (i.e., average food consumption, average
residue, etc.). The assessment is based on PDP, field trial (provides
an upper bound estimate of dietary exposure) and processing data.
Dietary exposure estimates are also factored by the estimated weighted
average usage, or ``percent crop treated'' data.iii. Cancer. The estimated exposure of the general U.S. population
(only) to trifluralin is 0.000028 mg/kg/day. Carcinogenic dietary risk
is based on the chronic exposure estimate for the general U.S.
population derived from the same residue, percent use, and averaged
consumption data. Note that the consumption data for the general U.S.
population represents all age groups, all geographic areas, all ethnic
groups, and incorporates reports of no consumption (non-user). The
final risk estimate is calculated by multiplying the average U.S.
exposure estimate by the trifluralin upper-bound potency factor, or
Q1*.iv. Anticipated residue and percent crop treated (PCT) information.
The dietary assessment relies on field trial, monitoring (PDP), and
usage data (PCT). Trifluralin residues were LOQ in/on all commodities
except alfalfa, collards, flax seeds, and mint field trials.
Section 408(b)(2)(E) of FFDCA authorizes EPA to use available data
and information on the anticipated residue levels of pesticide residues
in food and the actual levels of pesticide chemicals that have been
measured in food. If EPA relies on such information, EPA must require
that data be provided 5 years after the tolerance is established,
modified, or left in effect, demonstrating that the levels in food are
not above the levels anticipated. Following the initial data
submission, EPA is authorized to require similar data on a time frame
it deems appropriate. As required by section 408(b)(2)(E) of FFDCA, EPA
will issue a data call-in for information relating to anticipated
residues to be submitted no later than 5 years from the date of
issuance of this tolerance.Section 408(b)(2)(F) of FFDCA states that the Agency may use data
on the actual PCT for assessing chronic dietary risk only if the Agency
can make the following findings:Condition 1, that the data used are reliable and provide a valid
basis to show what percentage of the food derived from such crop is
likely to contain such pesticide residue.Condition 2, that the exposure estimate does not underestimate
exposure for any significant subpopulation group.Condition 3, if data are available on pesticide use and food
consumption in a particular area, the exposure estimate does not
understate exposure for the population in such area.In addition, the Agency must provide for periodic evaluation of any
estimates used. To provide for the periodic evaluation of the estimate
of PCT as required by section 408(b)(2)(F) of FFDCA, EPA may require
registrants to submit data on PCT.The Agency used PCT information as follows:
Crops with less than 2.5 PCT: Alfalfa, almonds, apples, corn,
grapes, lettuce, mint, onions, oranges, peaches, pears, pecans, prunes
and plums, sorghum, and walnuts.Crops with 5-20 PCT: Barley (5), broccoli (10), cantaloupes (15),
cauliflower (10), celery (10), cucumbers (5), dry peas (15), honeydew
(5), hops (5), lemons (5), okra (20), spring wheat (5), peanuts (10),
potatoes (5), pumpkins (5), radishes (10), soybeans (15), spinach (10),
squash (5), sugar beets (5), sugarcane (10), and watermelons (15).
Crops with 25 or more PCT: Asparagus (25), beans, green (35),
cabbage (45), carrots (55), collards (35), cotton (45), dry beans (30),
durum wheat (35), kale (25), greens, mustard (25), peas, green (30),
peppers (25), safflower (60), sunflowers (30), tomatoes (50), and
turnip (30).Modeling was performed by using the Dietary Exposure Evaluation
Model software with the Food Commodity Intake Database (DEEM-FCID) and
Lifeline. Using the DEEM-FCID method, an estimate of the residue level
in each food or food-form on the food commodity residue list is
multiplied by the average daily consumption estimate for that food/food
form. The resulting residue consumption estimate for each food/food
form is summed with the residue consumption estimates for all other
food/food forms on the commodity residue list to arrive at the total
average estimated exposure. Exposure is expressed in mg/kg body weight/
day and as a percent of the cPAD. This procedure is performed for each
population subgroup. Using the same consumption data, Lifeline converts
the Raw Agricultural Commodity an average daily exposure from a profile
of 1,000 individuals over a 1-year period. In conjunction, a Screening
Level Estimates of Agricultural Uses (SLUA) for trifluralin was used to
estimate PCT. The SLUA provides a quick snap shot of pesticide use, by
crop. For mint, the PCT of 3% was based on the SLUA report, which
averages the total pounds applied to trifluralin and PCT from 1997-2001.
The Agency believes that the three conditions listed in this unit
have been met. With respect to Condition 1, PCT estimates are derived
from Federal and private market survey data, which are reliable and
have a valid basis. EPA uses a weighted average PCT for chronic dietary
exposure estimates. This weighted average PCT figure is derived by
averaging State-level data for a period of up to 10 years, and
weighting for the more robust and recent data. A weighted average of
the PCT reasonably represents a person's dietary exposure over a
lifetime, and is unlikely to underestimate exposure to an individual
because of the fact that pesticide use patterns (both regionally and
nationally) tend to change continuously over time, such that an
individual is unlikely to be exposed to more than the average PCT over
a lifetime. For acute dietary exposure estimates, EPA uses an estimated
maximum PCT. The exposure estimates resulting from this approach
reasonably represent the highest levels to which an individual could be
exposed, and are unlikely to underestimate an individual's acute
dietary exposure. The Agency is reasonably certain that the percentage
of the food treated is not likely to be an underestimation. As to
Conditions 2 and 3, regional consumption information and consumption
information for significant subpopulations is taken into account
through EPA's computer-based model for evaluating the exposure of
significant subpopulations including several regional groups. Use of
this consumption information in EPA's risk assessment process ensures
that EPA's exposure estimate does not understate exposure for any
significant subpopulation group and allows the Agency to be reasonably
certain that no regional population is exposed to residue levels higher
than those estimated by the Agency. Other than the data available
through national food consumption surveys, EPA does not have available
information on the regional consumption of food to which trifluralin
may be applied in a particular area.2. Dietary exposure from drinking water. The Agency lacks
sufficient data to accurately determine dietary exposure from drinking
water. Therefore, contamination estimates for drinking water are
refined by PRZM-EXAMS modeling, incorporating percent cropped area
(PCA) data.[[Page 68296]]
Since trifluralin is registered on several crops, Tier II modeling
crop scenarios were selected to reflect crops with the highest uses of
trifluralin (soybeans and cotton), the maximum application rate
(sugarcane), and availability of scenarios. The maximum daily peak
concentration of trifluralin from PRZM/EXAMS simulation (38.1 parts per
billion (ppb)) is greater than the highest concentration in the United
States Geological Survey (USGS) National Water Quality Assessment
(NAWQA) monitoring database (1.74 ppb) for surface water. However, the
maximum annual average trifluralin concentration in surface water (1.9
ppb) is comparable to time weighted annual means (TWAM) concentrations
in USGS monitoring studies (0.618 ppb). The minimum criteria for
calculating TWAM concentration at a sampling station in a given year
was a single detection of trifluralin. As to groundwater, the maximum
trifluralin concentration predicted by SCI-GROW is 0.035 ppb and the
maximum single value from NAWQA monitoring of ground water is 0.150
ppb. The 99.8 percentile NAWQA value is 0.012 ppb. Because these values
are well below predicted and actual surface water values, no further
analysis of the reliability of the maximum NAWQA groundwater value was
conducted. Modeling was conducted using the maximum application rate
for specific crops. Modeling estimates from typical application rates
on specific crops will predict lower concentrations. For further
information on trifluralin modeling and monitoring, see docket ID
number OPP-2004-0142 at http://www.epa.gov/edocket/ for the following
documents: Trifluralin--Drinking Water Assessment for Tolerance
Reassessment Eligibility Decision and a memorandum entitled
Clarification of the Trifluralin Drinking Water Assessment for the
Health Effects Division (HED) Tolerance Reassessment (PC Code: 036101)
and characterization on relative differences of USGS NAWQA ground water
monitoring data and its comparison to SCI-GROW model predictions as
presented in the NRDC objection (see Imidacloprid in the Federal
Register of May 26, 2004 (69 FR 30042) (FRL-7355-7)) and the
trifluralin TRED.None of these models include consideration of the impact processing
(mixing, dilution, or treatment) of raw water for distribution as
drinking water would likely have on the removal of pesticides from the
source water. The primary use of these models by the Agency at this
stage is to provide a coarse screen for sorting out pesticides for
which it is highly unlikely that drinking water concentrations would
ever exceed human health levels of concern.3. 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).Trifluralin is currently registered for use on the following
residential non-dietary sites: Home lawns, vegetable gardens,
ornamental gardens (including planting beds, flowers, shrubs, and
trees), including other residential sites such as golf courses,
recreational parks, bike/golf cart paths, and cemeteries. The risk
assessment was conducted using the following residential exposure
assumptions:• For residential scenarios, homeowner handlers are expected
to complete all tasks associated with the use of a pesticide product,
including mixing/loading as well as application.• Residential handler exposure scenarios are only considered
to be short-term in nature due to the episodic uses associated with
homeowner products.• Label use rates and use information specific to
residential products serve as the basis for the risk calculations.• Area/volumes of spray or chemical used in the risk
assessment are based on Agency guidance specific to residential use
patterns.The Agency has determined that there are potential exposures to
residential handlers (i.e., mixer, loader, applicators) during the
usual use-patterns associated with trifluralin. Likewise, the Agency
has determined that there are potential post-application exposures to
adults and children in residential settings during the usual use-
patterns associated with trifluralin. For non-cancer post-application
risks, since there is no short-term dermal toxicological endpoint of
concern for trifluralin and no intermediate-term dermal exposure is
anticipated, the only assessment is for incidental ingestion by toddlers.
The Agency has also determined that there are potential post-
application cancer risks for adults in residential areas treated with
trifluralin. The following scenarios were assessed:• Dermal exposure to residue on lawns.
• Dermal exposure to golf course turfgrass.
• Dermal exposure to residue on home gardens.
For the residential turfgrass scenario, the cancer risks were combined
for residential handlers applying granular formulation to lawns with
post-application cancer risks to adults from exercising on just-treated
lawns. This combined two screening-level calculations.4. Cumulative exposure to 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.''Unlike other pesticides for which EPA has followed a cumulative
risk approach based on a common mechanism of toxicity, EPA has not made
a common mechanism of toxicity finding as to trifluralin and any other
substances and does not appear to produce a toxic metabolite produced
by other substances. For the purposes of this tolerance action,
therefore, EPA has not assumed that has 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 the policy
statements released by EPA's Office of Pesticide Programs concerning
common mechanism determinations and procedures for cumulating effects
from substances found to have a common mechanism on EPA's website at
http://www.epa.gov/pesticides/cumulative/.D. Safety Factor for Infants and Children
1. In general. Section 408 of FFDCA provides that EPA shall apply
an additional tenfold 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 that a different margin of safety will be safe
for infants and children. Margins of safety are incorporated into EPA
risk assessments either directly through use of a MOE analysis or
through using uncertainty (safety) factors in calculating a dose level
that poses no appreciable risk to humans.2. Prenatal and postnatal sensitivity. There are no residual
uncertainties for pre- and/or postnatal toxicity.3. Conclusion. There is a complete toxicity database for
trifluralin and exposure data are complete or are estimated based on
data that reasonably accounts for potential exposures. Based on this
information and the lack of any residual concerns for pre- and/or
postnatal toxicity, EPA concludes it has[[Page 68297]]
reliable data to remove the additional 10X FQPA safety factor.
E. Aggregate Risks and Determination of Safety
To estimate total aggregate exposure to a pesticide from food,
drinking water, and residential uses, the Agency calculates DWLOCs
which are used as a point of comparison against the model estimates of
a pesticide's concentration in water (EECs). DWLOC values are not
regulatory standards for drinking water. DWLOCs are theoretical upper
limits on a pesticide's concentration in drinking water in light of
total aggregate exposure to a pesticide in food and residential uses.
In calculating a DWLOC, the Agency determines how much of the
acceptable exposure (i.e., the PAD) is available for exposure through
drinking water [e.g., allowable chronic water exposure (mg/kg/day) =
cPAD - (average food + residential exposure)]. This allowable exposure
through drinking water is used to calculate a DWLOC.
A DWLOC will vary depending on the toxic endpoint, drinking water
consumption, and body weights. Default body weights and consumption
values as used by the USEPA Office of Water are used to calculate
DWLOCs: 2 liter (L)/70 kg (adult male), 2L/60 kg (adult female), and
1L/10 kg (child). Default body weights and drinking water consumption
values vary on an individual basis. This variation will be taken into
account in more refined screening-level and quantitative drinking water
exposure assessments. Different populations will have different DWLOCs.
Generally, a DWLOC is calculated for each type of risk assessment used:Acute, short-term, intermediate-term, chronic, and cancer.
When EECs for surface water and groundwater are less than the
calculated DWLOCs, OPP concludes with reasonable certainty that
exposures to the pesticide in drinking water (when considered along
with other sources of exposure for which OPP has reliable data) would
not result in unacceptable levels of aggregate human health risk at
this time. Because OPP considers the aggregate risk resulting from
multiple exposure pathways associated with a pesticide's uses, levels
of comparison in drinking water may vary as those uses change. If new
uses are added in the future, OPP will reassess the potential impacts
of residues of the pesticide in drinking water as a part of the
aggregate risk assessment process.Aggregate exposure assessment is based, in part, on the assumption
that there is a predictable level of chronic pesticide exposure,
attributable to food and drinking water, and this level is estimated on
a per day basis (mg/kg/day) by using averaged estimates of residue,
use, and consumption. This average, or ``background'' level of exposure
is assumed to be constant, not seasonal, and residential or other
exposures are additive to this background.For trifluralin, homeowner use is highly seasonal (mostly early
Spring) and this exposure will likely be acute (one day of golf) or
short-term (multiple residential applications). The route of exposure
may be oral (children on turf), dermal (at application or post-
application), or by inhalation (at application).1. Acute risk. A quantitative acute dietary assessment was not
conducted for the general U.S. population or population subgroups other
than females 13-49 because there was no appropriate single dose
endpoint. Exposure to trifluralin is not expected to pose an acute risk
to these population groups. The upper-bound acute risk estimate for
females 13-49 years of age is less than 1% of the aPAD at the 99.9\th\
exposure percentile. Results of the Lifeline analysis (see Table 3 of
this unit) are fully consistent with DEEM-FCID results (< 1% aPAD).
Population subgroup PAD, mg/kg/day Exposure, mg/kg/day % PAD Exposure, mg/kg/day %PAD Females 13-49 years 1 0.000262 0.03 0.000311 < 1
2. Chronic risk. Dietary risk for trifluralin is assessed by
comparing chronic dietary exposure estimates (in mg/kg/day) to the
trifluralin cPAD, with dietary risk expressed as a percent of the cPAD.
The cPAD is the chronic population adjusted dose; the chronic reference
dose (0.024 mg/kg/day) modified by the FQPA safety factor. The
trifluralin cPAD is 0.024 mg/kg/day based on a RfD of 0.024 mg/kg/day
(see section 3.3.1, Endpoint Selection Discussion in the Trifluralin:
Human Risk Assessment document), and incorporating the FQPA safety
factor of 1X (no additional factor) for the overall U.S. population or
any population subgroups.
The cPAD method of risk assessment is applicable to the oral
exposure route and is used to assess both food and drinking water
exposure. Exposure estimates that are less than 100% of the cPAD
indicate a determination of safety can be concluded (see Table 4 of
this unit).
Population subgroup PAD, mg/kg/day Exposure, mg/kg/day % PAD Exposure, mg/kg/day %PAD U.S. Population 0.024 0.000030 < 1 0.000019 < 1 All infants (< 1 year) 0.024 0.000062 < 1 0.000033 < 1 [[Page 68298]] Children 1-2 years 0.024 0.000073 < 1 0.000051 < 1 Children 3-5 years 0.024 0.000062 < 1 0.000039 < 1 Children 6-12 years 0.024 0.000041 < 1 0.000024 < 1 Youth 13-19 years and All Adults 0.024 0.000025 < 1 0.000016 < 1
3. Short-term risk. Short-term aggregate exposure takes into
account residential exposure plus chronic exposure to food and water
(considered to be a background exposure level). Dietary exposure is
assumed to be constant, not seasonal and residential or other exposures
are additive to this background. Homeowner use for trifluralin is
highly seasonal and this exposure will likely be acute or short-term.
Thus, the route of exposure may be oral (children on turf), dermal, or
inhalation where residential exposure could occur with the use of
trifluralin. However, no toxicological effects have been identified for
short-term toxicity. Therefore, the aggregate risk does not exceed the
Agency's level of concern.The chronic dietary exposure and risk estimates for the general
United States and population subgroups, are aggregate estimates based
on both food and drinking water sources. The aggregate (3 specific
exposure scenarios) incidental-oral exposure estimate for children on
turf is 0.00009 mg/kg/day. When combined with the estimated chronic
dietary exposure (0.000051 mg/kg/day) for children 1-2 years old, the
sum is 0.00014 mg/kg/day. Compared to the appropriate dose (10 mg/kg/
day) for short-term incidental-oral risk assessment, this aggregate
exposure estimate is much greater than the target MOE of 100, and a
conclusion of safety can be made.4. Intermediate-term risk. Intermediate and long-term residential
exposure is not expected for trifluralin and thus no such risk is
expected from the use of trifluralin.5. Cancer risk. When using the Q1* approach to assess a
pesticide, the Agency considers all exposure to be additive to
aggregate carcinogenic risk, regardless of exposure route or exposure
duration (per season). For trifluralin, this means that the chronic
exposure from foods (0.000022 mg/kg/day) is added to chronic exposure
due to drinking water (0.000008 mg/kg/day) and this in turn is added to
exposure estimated for residential use. Based on this assumption,
carcinogenic risk estimates are made for those applying trifluralin
themselves, each season, throughout adulthood (50 years).
The exposure and carcinogenic risk estimates for residential
applicators vary significantly depending on the application method,
even if other inputs (rate and area treated) remain the same. Since the
carcinogenic risk assessment attempts to reflect long-term exposure,
the most appropriate exposure estimate would be based on the most
common application method; the push-type spreader (for homeowners).
The risk estimate represents the probability of ``excess'' cancers
attributable to trifluralin. In general, the Agency considers
carcinogenic risk estimates in the range of 10-\6\, or less,
to be negligible. Applying the Q1* of 5.8 x
10-\3\ (mg/kg/day)-\1\ to the exposure value,
results in a cancer risk estimate of 1.64 x 10-\7\ (DEEM-
FCID) and 1.13 x 10-\7\ (Lifeline). Therefore, estimated
cancer risk is below the Agency's level of concern.6. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to the general population, and to infants and children from aggregate
exposure to trifluralin residues.IV. Other Considerations
A. Analytical Enforcement Methodology
Adequate enforcement methodology (GC method; TFN0291) using an
electron capture detector (ECD), Eli Lilly Method AM-AA-CA-R023-AA-755,
and GRM 92.11) is available to enforce the tolerance expression. The
method may be requested from: Chief, Analytical Chemistry Branch,
Environmental Science Center, 701 Mapes Rd., Ft. Meade, MD 20755-5350;
telephone number: (410) 305-2905; e-mail address:
residuemethods@epa.gov.B. International Residue Limits
Canada, Codex, and Mexico do not have maximum residue limits (MRLs)
for residues of trifluralin in mint oil or in/on spearmint and
peppermint tops. Furthermore, no maximum MRLs for trifluralin have been
established or proposed by Codex for any agricultural commodity.
Therefore, no compatibility questions exist with respect to U.S. tolerances.C. Conditions
Currently, there are no additional requirements. Also, all existing
tolerances are being maintained at current levels and are considered to
be reassessed by the Trifluralin Tolerance Reassessment Eligibility
Decision signed on August 31, 2004.V. Conclusion
A tolerance is proposed for residues of trifluralin in mint oil at
2.0 ppm.VI. Statutory and Executive Order Reviews
This proposed rule establishes a tolerance under section 408(d) of
FFDCA in response to a petition submitted to the Agency. The Office of
Management and Budget (OMB) has exempted these types of actions from
review under Executive Order 12866, entitled Regulatory Planning and
Review (58 FR 51735, October 4, 1993). Because this proposed rule has
been exempted from review under Executive Order 12866 due to its lack
of significance, this proposed rule is not subject to Executive Order
13211, Actions Concerning Regulations That Significantly Affect Energy
Supply, Distribution, or Use (66 FR 28355, May 22, 2001). This proposed
rule does not contain any information collections subject to OMB
approval under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et
seq., or impose any[[Page 68299]]
enforceable duty or contain any unfunded mandate as described under
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Public Law
104-4). Nor does it require any special considerations under Executive
Order 12898, entitled Federal Actions to Address Environmental Justice
in Minority Populations and Low-Income Populations (59 FR 7629,
February 16, 1994); or OMB review or any Agency action under Executive
Order 13045, entitled Protection of Children from Environmental Health
Risks and Safety Risks (62 FR 19885, April 23, 1997). This action does
not involve any technical standards that would require Agency
consideration of voluntary consensus standards pursuant to section
12(d) of the National Technology Transfer and Advancement Act of 1995
(NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note).
Because this action will not have an adverse impact on small business,
I certify, under the Regulatory Flexibility Act (5 U.S.C. 601 et
seq.), that this action will not have a significant economic impact on
a substantial number of small entities. In addition, the Agency has
determined that this action will not have a substantial direct effect
on States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government, as specified in Executive Order 13132,
entitled Federalism (64 FR 43255, August 10, 1999). Executive Order
13132 requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.'' This
proposed rule directly regulates growers, food processors, food
handlers, and food retailers, not States. This action does not alter
the relationships or distribution of power and responsibilities
established by Congress in the preemption provisions of section
408(n)(4) of FFDCA. For these same reasons, the Agency has determined
that this proposed rule does not have any ``tribal implications'' as
described in Executive Order 13175, entitled Consultation and
Coordination with Indian Tribal Governments (59 FR 22951, November 6,
2000). Executive Order 13175, requires EPA to develop an accountable
process to ensure ``meaningful and timely input by tribal officials in
the development of regulatory policies that have tribal implications.''
``Policies that have tribal implications'' is defined in the Executive
order to include regulations that have ``substantial direct effects on
one or more Indian tribes, on the relationship between the Federal
Government and the Indian tribes, or on the distribution of power and
responsibilities between the Federal Government and Indian tribes.''
This proposed rule will not have substantial direct effects on tribal
governments, on the relationship between the Federal Government and
Indian tribes, or on the distribution of power and responsibilities
between the Federal Government and Indian tribes, as specified in
Executive Order 13175. Thus, Executive Order 13175 does not apply to
this proposed rule.List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: November 16, 2004.
Debra Edwards,
Director, Special Review and Reregistration Division, Office of
Pesticide Programs.Therefore, it is proposed that 40 CFR chapter I be amended as follows:
PART 180--[AMENDED]
1. The authority citation for part 180 would continue to read as
follows:
Authority: 21 U.S.C. 321(q), 346a and 371.
2. Section 180.207 would be amended by revising the table in
paragraph (a) to read as follows:
Sec. 180.207 Trifluralin; tolerances for residues.
(a) * * *
------------------------------------------------------------------------
Commodity - - - - - - - - - - - - - - - - Parts per million
------------------------------------------------------------------------
Alfalfa, hay............................................... 0.2
Asparagus.................................................. 0.05
Barley, hay................................................ 0.05
Barley, straw.............................................. 0.05
Bean, mung, sprouts........................................ 2.0
Carrot, roots.............................................. 1.0
Corn, field, forage........................................ 0.05
Corn, field, grain......................................... 0.05
Corn, field, stover........................................ 0.05
Cotton, undelinted seed.................................... 0.05
Cress, upland.............................................. 0.05
Flax, seed................................................. 0.05
Friut, citrus, group 10.................................... 0.05
Fruit, stone, group 12..................................... 0.05
Grain, crop, except corn, sweet and rice grain............. 0.05
Grape...................................................... 0.05
Hop........................................................ 0.05
Legume, forage............................................. 0.05
Nut, tree, group 14........................................ 0.05
Peanut..................................................... 0.05
Peppermint oil............................................. 2.0
Peppermint, tops........................................... 0.05
Rapeseed, seed............................................. 0.05
Safflower, seed............................................ 0.05
Sorghum, forage............................................ 0.05
Sorghum, grain, stover..................................... 0.05
Spearmint oil.............................................. 2.0
Spearmint, tops............................................ 0.05
Sugarcane, cane............................................ 0.05
Sunflower, seed............................................ 0.05
Vegetable, cucurbit, group 9............................... 0.05
Vegetable, fruiting, group 8............................... 0.05
Vegetables, leafy.......................................... 0.05
Vegetables, root (exc. carrots)............................ 0.05
Vegetables, seed and pod................................... 0.05
Wheat, grain............................................... 0.05
Wheat, straw............................................... 0.05
------------------------------------------------------------------------
* * * * *
[FR Doc. 04-25941 Filed 11-23-04; 8:45 am]
BILLING CODE 6560-50-S