[Federal Register Volume 69, Number 226 (Wednesday, November 24, 2004)]
[Proposed Rules]
[Pages 68287-68299]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-25941]
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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 [email protected],
[[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:
[email protected].
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
------------------------------------------------------------------------
MRID No. (year)/
Guideline No./Study Type Classification/ Results/Comments
Doses
------------------------------------------------------------------------
870.3100 00157154 (1983) NOAEL = Not achieved
2-Week R-F Feeding--Rats 0; 6,500 ppm LOAEL = 6,500 ppm based
(male). range-finding on renal epithelial
study for damage, urine triple
00157156 phosphates crystals and
(1985), urinary sediment
41038301
(1986).
Acceptable/
Nonguideline.
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870.3100 00151906 (1980) NOAEL = 2,000 ppm (154/
90-Day Oral toxicity--Rat.... 0; 800; 2,000; 168 mg/kg/day, Male/
or 5,000 ppm. Female (M/F))
M: 0, 59, 154, LOAEL = 5,000 (392/
and 392 421(mg/kg/day), M/F)
milligram/ Based on minor decreases
kilogram/day in overall body weight
(mg/kg/day). gains and food
F: 0, 69, 168, consumption in males
and 421 mg/kg/ and females, decreased
day. hemoglobin, alkaline
Acceptable/ phosphatase, and
Guideline. alanine
aminotransferase in the
males, and increased
absolute and relative
(to body) liver weights
in males and females
------------------------------------------------------------------------
870.3200 41993810 (1991) Systemic NOAEL =1,000 mg/
21/28-Day dermal toxicity-- 0, 100, 500, or kg/day
Rabbit. 1,000 mg/kg/ Systemic LOAEL = Not
day achieved
(formulation Dermal NOAEL = Not
containing achieved
35.8% Dermal LOAEL = 100 mg/kg/
trifluralin day, edema, and/or
and 2.6% XRD- scaling and fissuring
498). 100 mg/kg/day based
Acceptable/ skin irritation
Guideline.
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870.3200 00153171 (1982) Systemic NOAEL = 1,000
31-Day dermal toxicity--Rat.. 0; 40; 200; or mg/kg/day (limit dose)
1,000 mg/kg/ Systemic LOAEL = Not
day. achieved
Acceptable/ Dermal NOAEL = 40 mg/kg/
Guideline. day
Dermal LOAEL = 200 mg/kg/
day based on sub-
epidermal inflamation
and ulcerations inmales
and females
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[[Page 68290]]
870.3200 00152888 (1985) Systemic NOAEL = 1,000
21/28-Day dermal toxicity-- 0; 1,000 mg/kg/ mg/kg/day
Rat. day (limit Systemic LOAEL = Not
dose). achieved
Acceptable/ Dermal NOAEL= Not
Guideline. achieved
Dermal LOAEL = 1,000 mg/
kg/day (limit dose)
based on erythema,
edema, and
desquamination of the
treated skin
------------------------------------------------------------------------
870.3465 40392312 (1987) NOAEL = 301 mg/m\3\
30-Day inhalation toxicity... reformat of LOAEL = 1,006 mg/m\3\
00151904 based on increased
(1982) bilirubin in females
0; 100; 301; and incidences of
1,006 mg/ dyspnea and ruffled fur
m\3\(6 hours/ in males and females
day 5 days/
week for up to
30 days).
Acceptable/
Nonguideline.
------------------------------------------------------------------------
870.3700 00151899 Systemic Maternal NOAEL
Developmental Toxicity Study-- (1983), 159620 = 100 mg/kg/day
Rat. (1986), Systemic Maternal LOAEL
40392310 = 500 mg/kg/day based
(1987) on mortality, clinical
0, 20, 100, 500 signs, decreased body
mg/kg/day. 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
resorptions
------------------------------------------------------------------------
870.3700 00152419 (1984) Maternal NOAEL = 475 mg/
Developmental Toxicity Study-- 0; 100; 225; kg/day
Rat. 470; or 1,000 Maternal LOAEL = 1,000
mg/kg/day. mg/kg/day based on
Acceptable/ decreased body weights
Guideline. 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 established
------------------------------------------------------------------------
870.3700 00152421 (1984) Maternal NOAEL = 100 mg/
Developmental Toxicity-- 0, 100, 225, kg/day
Rabbit. 500 mg/kg/day. Maternal LOAEL = 225 mg/
Acceptable/ kg/day based on
Guideline. 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
abortions
------------------------------------------------------------------------
870.3800 00151901 (1984) Parental NOAEL = 200 ppm
2-Generation reproduction-- 00151902 (1984) (10 mg/kg/day)
Rat. Feed analysis. Parental LOAEL = 650 ppm
00151903 (1984) (32.5 mg/kg/day) based
Path. on mortality due to
0; 200; 650; acute renal failure and
2,000 ppm. increased lesions of
0, 20, 32.5, the renal proximal
200 mg/kg/day tubules in the F1
(1 ppm = 0.5 females; increased
mg/kg/day). relative (to body)
Acceptable/ weights of the liver,
Guideline. 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
established
------------------------------------------------------------------------
870.3800 00162543 Parental NOAEL = 200 ppn
2-Generation reproduction-- (1986), (15 mg/kg/day)
Rat. 44135107 Parental LOAEL = 630 ppm
(1996) (47 mg/kg/day) based on
0; 200; 630; decreased body weight
2,000 ppm. gains (BWG) and food
0, 15, 47, 148 consumption
mg/kg/day. Offspring NOAEL = 200
Acceptable/ ppm (15 mg/kg/day)
Guideline. 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
established
------------------------------------------------------------------------
870.3800 40405007 (1987) Parental NOAEL = 450 ppm
2-Generation reproduction-- 0; 50; 450; (35/42 mg/kg/day M/F)
Rat. 4,000 ppm. Parental LOAEL = 4,000
M: 0, 3.9, 35, ppm (295/337 mg/kg/day
295 mg/kg/day. M/F) based on decreased
F: 0, 4.7, 42, body weights, body
337 mg/kg/day. weight gains, food
Acceptable/ consumption, and food
Guideline. 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 00151908 NOAEL = 30 ppm (0.8 mg/
1-Year Oral (capsule) Study-- (1984), kg/day)
Dog. 00159618 LOAEL = 150 ppm (3.8 mg/
(1985) kg/day) based on
0, 30, 150, or increased absolute
750 ppm. liver weights in males
0.0, 0.8, 3.8,
18.8 mg/kg /
day.
Acceptable/
Guideline.
------------------------------------------------------------------------
870.4100 42447001 (1992) Systemic NOAEL = 2.4 mg/
1-Year Oral (capsule) Study-- 0, 0.75, 2.4, kg/day
Dog. 40 mg/kg/day. Systemic LOAEL = 40 mg/
Acceptable/ kg/day, based on
Guideline. 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 males
------------------------------------------------------------------------
870.4300 00162457 NOAEL = 800 ppm (40/53
24-Month Chronic Toxicity/ (1985), mg/kg/day M/F)
Carcinogenicity Study--Rat. 00162458 LOAEL = 3,200 ppm (169/
(1985) 219 mg/kg/day M/F)
0; 200; 800; or based on decreases in
3,200 ppm. body weight and body
M: 0, 10, 40, weight gains
and 169 mg/kg/ At the doses tested, the
day. carcinogenic potential
F: 0, 13, 53, of trifluralin was
and 219 mg/kg/ negative. Dosing was
day. considered adequate
Acceptable/ based on differences in
Guideline. body weight and body
weight gains.
------------------------------------------------------------------------
870.4300 00158935 Sys NOAEL = 800 ppm (118/
24- Month Carcinogenicity (1986), 165 mg/kg/day in males/
Study--Mouse. 40392313 females); highest dose
(1987) tested
0, 50, 200, or System LOAEL = Not
800 ppm. achieved
M: 0, 7.5, 29, NOAEL for the range
and 118 mg/kg/ finder was 2500 ppm
day. (375 mg/kg/day), the
F: 0, 10.5, 41, highest dose tested
and 165 mg/kg/
day.
Unacceptable/
Guideline.
------------------------------------------------------------------------
870.5100 MRID 00148345 There was no evidence of
Bacterial Reverse Gene (1984) induced mutant colonies
Mutation Assay. Acceptable/ over background.
Guideline.
------------------------------------------------------------------------
870.5100 MRID 40334707 There was no evidence of
Bacterial Reverse Gene (1987) induced mutant colonies
Mutation Assay. Acceptable/ over background.
Guideline.
------------------------------------------------------------------------
870.5100 MRID 00153173 There was no evidence of
Bacterial Reverse Gene (1979) induced mutant colonies
Mutation Assay. Acceptable/ over background.
Guideline.
------------------------------------------------------------------------
870.5250 MRID 00151898 There was no
Gene Mutation Assay--Yeast... (1982) concentration-related
Acceptable/ positive response of
Guideline. induced mutant colonies
over background.
------------------------------------------------------------------------
870.5300 MRID 00126661 There was no
In vitro Mammalian Cell Gene Acceptable/ concentration-related
Mutation Assay. Guideline. positive response of
induced mutant colonies
over background.
------------------------------------------------------------------------
870.5450 MRID 00148319 There was no time-
Dominant Lethal--Rat......... (1984) related positive
Acceptable/ response of increased
Guideline. pre- or post-
implantation loss
compared to controls.
------------------------------------------------------------------------
870.5300 MRID 40765601 There was no evidence of
Forward Gene Mutation Assay.. (1988) induced mutant colonies
Acceptable/ over background in the
Guideline. presence or absence of
S9-activation.
------------------------------------------------------------------------
870.5300 MRID 00148318 There was no evidence of
Forward Gene Mutation Assay.. (1984) induced mutant colonies
Acceptable/ over background in the
Guideline. presence or absence of
S9-activation.
------------------------------------------------------------------------
870.5385 MRID 40765603 There was no evidence of
In Vivo Mammalian (1988) chromosome aberration
Cytogenetics (Bone Marrow/ Acceptable/ induced over
Spermatogonial Aberration Guideline. background.
Test).
------------------------------------------------------------------------
[[Page 68292]]
870.5385 MRID 00148320 There was no evidence of
In Vivo Mammalian Acceptable/ chromosome aberration
Cytogenetics (Bone Marrow Guideline. induced over
Chromosome Aberration Test). background.
------------------------------------------------------------------------
870.5395 MRID 00151895 There was no significant
In Vivo Mouse Erythrocyte (1981) increase in the
Micronucleus Assay. Acceptable/ frequency of
Guideline. micronucleated
polychromatic
erythrocytes in bone
marrow compared to
controls.
------------------------------------------------------------------------
870.5450 MRID 00151896 There was no time-
Dominant Lethal--Mouse....... (1984) related positive
Acceptable/ response of increased
Guideline. pre- or post-
implantation loss
compared to controls.
------------------------------------------------------------------------
870.5550 MRID 40765602 There was no evidence
Unscheduled DNA synthesis in (1988) that unscheduled DNA
mammalian cell culture. Acceptable/ synthesis, as
Guideline. determined by
radioactive tracer
procedures (nuclear
silver grain counts),
was induced.
------------------------------------------------------------------------
870.5550 MRID 00151894 There was no evidence
Unscheduled DNA synthesis in (1982) that unscheduled DNA
mammalian cell culture. Acceptable/ synthesis, as
Guideline. determined by liquid
scintillation counting
procedures, was
induced.
------------------------------------------------------------------------
870.5900 MRID 00133426 There was no evidence of
In Vivo Sister Chromatid (1983) SCE induced over
Exchange Assay. Acceptable/ background.
Guideline.
------------------------------------------------------------------------
870.7845 41218901 (1989) The objective of this
Metabolism--Rat.............. Acceptable/ study was to identify
Urinary metabolites.......... Guideline. 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 00157156 NOAEL = 200 ppm (10.7 mg/
3-Month Feeding--Rat with (1985), kg/day)
Urinalysis Study. 40138301(1986) LOAEL for nephrotoxicity
, 41086101 = 800 ppm (42.2mg/kg/
(1989) day), based on the
0; 50; 200; presence of cortical
800; 3,200; tubular cytoplasmic
and 6,400 ppm. hyaline droplets;
0, 2.6, 10.7, increased total
42.2, 170.2, protein, aspartate
and 342.1 mg/ aminotransferase (AST),
kg/day. and lactate
Acceptable/ dehydrogenase (LDH) in
Nonguideline.. 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 Endpoints
The 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
----------------------------------------------------------------------------------------------------------------
Dose used in risk Special FQPA SF* target Study and toxicological
Exposure scenario assessment, UF MOE effects
----------------------------------------------------------------------------------------------------------------
Acute Dietary NOAEL = 100 mg/kg/day Special FQPA SF = 1 Developmental Toxicity
(Females 13-50 years of age)......... UF = 100............... aPAD = 1.0 mg/kg/day... Study--Rat
Acute RfD = 1.0 mg/kg/ LOAEL = 500 mg/kg/day
day. based on increased
total litter
resorptions
----------------------------------------------------------------------------------------------------------------
Acute Dietary No appropriate single dose endpoint was selected.
(General population, including
infants and children).
----------------------------------------------------------------------------------------------------------------
Chronic Dietary NOAEL = 2.4 mg/kg/day Special FQPA SF = 1 Chronic Toxicity
All population....................... UF = 100............... cPAD = 0.024 mg/kg/day. (capsule)--Dog
Chronic RfD = 0.024 mg/ LOAEL = 40 mg/kg/day
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
----------------------------------------------------------------------------------------------------------------
Short-Term Incidental Oral NOAEL = 10 mg/kg/day MOE = 100 2-Generation
(1-30 days).......................... Reproduction Study--
Rat
LOAEL = 32.5 mg/kg/day
based on decreased pup
weights in both
generations
----------------------------------------------------------------------------------------------------------------
Intermediate-Term Incidental Oral NOAEL = 10 mg/kg/day MOE = 100 Special Urinalysis
(1-6 months)......................... 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
volume
----------------------------------------------------------------------------------------------------------------
Short-Term Dermal No quantification required since there was no systemic toxicity at the
(1 to 30 days)....................... 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 Oral study Residential MOE = 100 Special Urinalysis
(1 to 6 months)...................... NOAEL = 10 mg/kg/day... Occupational MOE = 100. Study--Rat
(dermal absorption rate LOAEL = 40mg/kg/day
= 3%). 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
volume
----------------------------------------------------------------------------------------------------------------
Long-Term Dermal Oral study Residential MOE = 100 Chronic Toxicity
(>6 months).......................... NOAEL = 2.4 mg/kg/day.. Occupational MOE = 100. (capsule)--Dog
(dermal absorption rate LOAEL = 40mg/kg/day
= 3% when appropriate). 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 Inhalation study NOAEL= Residential MOE = 100 30-Day Inhalation
(1 to 30 days)....................... 81 mg/kg/day Occupational MOE = 100. 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
females
----------------------------------------------------------------------------------------------------------------
Intermediate-Term Inhalation Oral study NOAEL = 10 Residential MOE = 100 Special Urinalysis
(1 to 6 months)...................... mg/kg/day Occupational MOE = 100. Study--Rat
(inhalation absorption LOAEL = 40 mg/kg/day
rate = 100%). 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
volume
----------------------------------------------------------------------------------------------------------------
Long-Term Inhalation Oral studyNOAEL= 2.4 mg/ Residential MOE = 100 Chronic Toxicity
(>6 months).......................... kg/day Occupational MOE = 100. (capsule)--Dog
(inhalation absorption LOAEL = 40 mg/kg/day
rate = 100%). 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
----------------------------------------------------------------------------------------------------------------
Cancer Q1* = 5.8 X 10-\3\ (mg/kg/day)-\1\. The Agency concluded that trifluralin
(Oral, dermal, inhalation)........... 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 Assessment
1. 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).
Table 3.--Aggregate Risk Assessment for Acute Exposure to Trifluralin (Food/ Water Combined)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Acute Dietary Estimates (99.9\th\ Percentile of Exposure)
---------------------------------------------------------------------------------------------------------------------------------------------------------
DEEM-FCID Lifeline
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).
Table 4.--Chronic Dietary Exposure and Risk Estimates
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chronic PAD Dietary Estimates
---------------------------------------------------------------------------------------------------------------------------------------------------------
DEEM-FCID Lifeline
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:
[email protected].
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 (65 FR 67249, 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) * * *
------------------------------------------------------------------------
Parts per
Commodity 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