[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.
------------------------------------------------------------------------
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.
------------------------------------------------------------------------
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
------------------------------------------------------------------------

[[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