[Federal Register: March 20, 2003 (Volume 68, Number 54)]
[Notices]
[Page 13703-13708]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20mr03-60]
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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2003-0056; FRL-7296-5]
Flufenacet; Notice of Filing Pesticide Petitions to Establish
Tolerances for a Certain Pesticide Chemical in or on Food
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the initial filing of a pesticide
petition proposing the establishment of regulations for residues of
flufenacet in or on various food commodities.
DATES: Comments, identified by docket ID number OPP-2003-0056, must be
received on or before April 21, 2003.
ADDRESSES: Comments may be submitted electronically, by mail, or
through hand delivery/courier. Follow the detailed instructions as
provided in Unit I. of the SUPPLEMENTARY INFORMATION.
FOR FURTHER INFORMATION CONTACT: James A. Tompkins, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 305-5697; e-mail address:
tompkins.jim@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer, or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
[sbull] Crop production (NAICS 111)
[sbull] Animal production (NAICS 112)
[sbull] Food manufacturing (NAICS 311)
[sbull] Pesticide manufacturing (NAICS 32532)
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
CONTACT.
B. How Can I Get Copies of this Document and Other Related Information?
1. Docket. EPA has established an official public docket for this
action under docket identification (ID) number OPP-2003-0056. The
official public docket consists of the documents specifically
referenced in this action, any public comments received, and other
information related to this action. Although a part of the official
docket, the public docket does not include Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. The official public docket is the collection of materials
that is available for public viewing at the Public Information and
Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall 2,
1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The docket telephone number is (703) 305-5805.
2. Electronic access. You may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public
comments, access the index listing of the contents of the official
public docket, and to access those documents in the public docket that
are available electronically. Although not all docket materials may be
available electronically, you may still access any of the publicly
available docket materials through the docket facility identified in
Unit I.B.1. Once in the system, select ``search,'' then key in the
appropriate docket ID number.
Certain types of information will not be placed in the EPA Dockets.
Information claimed as CBI and other information whose disclosure is
restricted by statute, which is not included in the official public
docket, will not be available for public viewing in EPA's electronic
public docket. EPA's policy is that copyrighted material will not be
placed in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. To the extent
feasible, publicly available docket materials will be made available in
EPA's electronic public docket. When a document is selected from the
index list in EPA Dockets, the system will identify whether the
document is available for viewing in EPA's electronic public docket.
[[Page 13704]]
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified in Unit I.B. EPA intends to work towards
providing electronic access to all of the publicly available docket
materials through EPA's electronic public docket.
For public commenters, it is important to note that EPA's policy is
that public comments, whether submitted electronically or in paper,
will be made available for public viewing in EPA's electronic public
docket as EPA receives them and without change, unless the comment
contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. When EPA identifies a comment
containing copyrighted material, EPA will provide a reference to that
material in the version of the comment that is placed in EPA's
electronic public docket. The entire printed comment, including the
copyrighted material, will be available in the public docket.
Public comments submitted on computer disks that are mailed or
delivered to the docket will be transferred to EPA's electronic public
docket. Public comments that are mailed or delivered to the docket will
be scanned and placed in EPA's electronic public docket. Where
practical, physical objects will be photographed, and the photograph
will be placed in EPA's electronic public docket along with a brief
description written by the docket staff.
C. How and To Whom Do I Submit Comments?
You may submit comments electronically, by mail, or through hand
delivery/courier. To ensure proper receipt by EPA, identify the
appropriate docket ID number in the subject line on the first page of
your comment. Please ensure that your comments are submitted within the
specified comment period. Comments received after the close of the
comment period will be marked ``late.'' EPA is not required to consider
these late comments. If you wish to submit CBI or information that is
otherwise protected by statute, please follow the instructions in Unit
I.D. Do not use EPA Dockets or e-mail to submit CBI or information
protected by statute.
1. Electronically. If you submit an electronic comment as
prescribed in this unit, EPA recommends that you include your name,
mailing address, and an e-mail address or other contact information in
the body of your comment. Also include this contact information on the
outside of any disk or CD ROM you submit, and in any cover letter
accompanying the disk or CD ROM. This ensures that you can be
identified as the submitter of the comment and allows EPA to contact
you in case EPA cannot read your comment due to technical difficulties
or needs further information on the substance of your comment. EPA's
policy is that EPA will not edit your comment, and any identifying or
contact information provided in the body of a comment will be included
as part of the comment that is placed in the official public docket,
and made available in EPA's electronic public docket. If EPA cannot
read your comment due to technical difficulties and cannot contact you
for clarification, EPA may not be able to consider your comment.
i. EPA Dockets. Your use of EPA's electronic public docket to
submit comments to EPA electronically is EPA's preferred method for
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/
edocket
, and follow the online instructions for submitting comments.
Once in the system, select ``search,'' and then key in docket ID number
OPP-2003-0056. The system is an ``anonymous access'' system, which
means EPA will not know your identity, e-mail address, or other contact
information unless you provide it in the body of your comment.
ii. E-mail. Comments may be sent by e-mail to opp-docket@epa.gov,
Attention: Docket ID Number OPP-2003-0056. In contrast to EPA's
electronic public docket, EPA's e-mail system is not an ``anonymous
access'' system. If you send an e-mail comment directly to the docket
without going through EPA's electronic public docket, EPA's e-mail
system automatically captures your e-mail address. E-mail addresses
that are automatically captured by EPA's e-mail system are included as
part of the comment that is placed in the official public docket, and
made available in EPA's electronic public docket.
iii. Disk or CD ROM. You may submit comments on a disk or CD ROM
that you mail to the mailing address identified in Unit I.C.2. These
electronic submissions will be accepted in WordPerfect or ASCII file
format. Avoid the use of special characters and any form of encryption.
2. By mail. Send your comments to: Public Information and Records
Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460-0001, Attention: Docket ID Number OPP-2003-0056.
3. By hand delivery or courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Office of Pesticide
Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall
2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket
ID Number OPP-2003-0056. Such deliveries are only accepted during the
docket's normal hours of operation as identified in Unit I.B.1.
D. How Should I Submit CBI to the Agency?
Do not submit information that you consider to be CBI
electronically through EPA's electronic public docket or by e-mail. You
may claim information that you submit to EPA as CBI by marking any part
or all of that information as CBI (if you submit CBI on disk or CD ROM,
mark the outside of the disk or CD ROM as CBI and then identify
electronically within the disk or CD ROM the specific information that
is CBI). Information so marked will not be disclosed except in
accordance with procedures set forth in 40 CFR part 2.
In addition to one complete version of the comment that includes
any information claimed as CBI, a copy of the comment that does not
contain the information claimed as CBI must be submitted for inclusion
in the public docket and EPA's electronic public docket. If you submit
the copy that does not contain CBI on disk or CD ROM, mark the outside
of the disk or CD ROM clearly that it does not contain CBI. Information
not marked as CBI will be included in the public docket and EPA's
electronic public docket without prior notice. If you have any
questions about CBI or the procedures for claiming CBI, please consult
the person listed under FOR FURTHER INFORMATION CONTACT.
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
notice.
7. To ensure proper receipt by EPA, be sure to identify the docket
ID number
[[Page 13705]]
assigned to this action in the subject line on the first page of your
response. You may also provide the name, date, and Federal Register
citation.
II. What Action is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical in or on various food commodities under section 408
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that this petition contains data or information
regarding the elements set forth in FFDCA section 408(d)(2); however,
EPA has not fully evaluated the sufficiency of the submitted data at
this time or whether the data support granting of the petition.
Additional data may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: March 10, 2003.
Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.
Summary of Petition
The petitioner's summary of the pesticide petition is printed below
as required by FFDCA section 408(d)(3). The summary of the petition was
prepared by the petitioner and represents the view of the petitioner.
The petition summary announces the availability of a description of the
analytical methods available to EPA for the detection and measurement
of the pesticide chemical residues or an explanation of why no such
method is needed.
Bayer CropScience
PP 6F4631 and OF6095
EPA has received pesticide petitions (6F4631 and 0F6095) from
BayerCropScience, P.O. Box 12014, 2 T.W. Alexander Drive, Research
Triangle Park, NC 27709 proposing, pursuant to section 408(d) of the
Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to
amend 40 CFR 180.527(a) by establishing permanent tolerance[s] for
residues of the herbicide flufenacet; N-(4-fluorophenyl)-N-(1-
methylethyl)-2-[[5-(trifluoromethyl)-1,3,4-thiadiazol-2-
yl]oxy]acetamide and metabolites containing the 4-fluoro-N-methylethyl
benzenamine moiety in or on the raw agricultural commodities: corn,
field, forage at 0.4 parts per million (ppm); corn, field, grain at
0.05 ppm; corn, field, stover at 0.4 ppm; soybean, seed at 0.1 ppm (PP
6F4631); cattle, fat at 0.05 ppm; cattle, kidney at 0.5 ppm; cattle,
meat at 0.05 ppm; cattle, meat byproducts at 0.1 ppm; goat, fat at 0.05
ppm; goat, kidney at 0.5 ppm; goat, meat at 0.05 ppm; goat, meat
byproducts at 0.1 ppm; hog, fat at 0.05 ppm; hog, kidney at 0.5 ppm;
hog, meat at 0.05 ppm; hog, meat byproducts at 0.1 ppm; horse, fat at
0.05 ppm; horse, kidney at 0.5 ppm; horse, meat at 0.05 ppm; horse,
meat byproducts at 0.1 ppm; sheep, fat at 0.05 ppm; sheep, kidney at
0.5 ppm; sheep, meat at 0.05 ppm; sheep, meat byproducts at 0.1 ppm;
wheat, forage at 10.0 ppm; wheat, grain at 1.0 ppm; wheat, hay at 2.0
ppm; wheat, straw at 0.50 ppm (PP 0F6095); and 40 CFR 180.527(d) by
establishing permanent tolerances for indirect or inadvertent residues
of the herbicide flufenacet; N-(4-fluorophenyl)-N-(1-methylethyl)-2-
[[5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl]oxy]acetamide and
metabolites containing the 4-fluoro-N-methylethyl benzenamine moiety in
or on the following raw agricultural commodities from the application
of this herbicide to the raw agricultural commodities listed in 40 CFR
180.527(a): alfalfa, forage at 0.1 ppm; alfalfa, hay at 0.1 ppm;
alfalfa, seed at 0.1 ppm; clover, forage at 0.1 ppm; clover, hay at 0.1
ppm; grain, cereal, group 15, except rice at 0.4 ppm; grain, cereal,
forage, fodder and straw, group 16, except rice, forage at 10.0 ppm;
grain, cereal, forage, fodder and straw, group 16, except rice, stover
at 3.0 ppm; grain, cereal, forage, fodder, and straw, group 16, except
rice, straw at 1.0 ppm; grass, forage, fodder, and hay, group 17 at 0.1
ppm (PP 6F4631).
A. Residue Chemistry
1. Plant metabolism. The nature of the residue in field corn,
soybean, rotational crops and livestock is adequately understood. The
residues of concern for the tolerance expression are flufenacet parent
and its metabolites containing the 4-fluoro-N-methylethyl benzenamine
moiety. Based on the results of animal metabolism studies, it is
unlikely that secondary residues would occur in animal commodities from
the use of flufenacet on field corn and soybean.
2. Analytical method. An adequate analytical method,
gaschromatography/mass spectrometry with selected ion monitoring, is
available for enforcement purposes. Because of the long lead time from
establishing these tolerances to publication of the enforcement
methodology in the Pesticide Analytical Manual, Vol. II, the analytical
methodology is being made available in the interim to anyone interested
in pesticide enforcement when requested from: Calvin Furlow, Public
Information and Records Integrity Branch, Information Resources and
Services Division (7502C), Office of Pesticide Programs, Environmental
Protection Agency, 401 M St., SW., Washington, DC 20460. Office
location and telephone number: Room 119E, CM 2, 1921 Jefferson
Davis Highway, Arlington, VA 22202, (703) 305-5937).
3. Magnitude of residues. Field residue trials were conducted
across the major regions of corn and soybean production in the United
States. In both cases, the treatment regime was selected to represent
the use patterns that are most likely to result in the highest residue
and used a 60% dry flowable formulation of the active ingredient. In
all cases, the test plots received a single application of the product
at a rate of 0.9 lbs. of active ingredient per acre.
For corn, flufenacet was applied at preplant soil incorporated,
preemergence broadcast, and early postemergence application timings.
The highest average field trial residues in corn raw agricultural
commodities were 0.36 ppm in forage, 0.16 ppm in fodder, and less than
0.05 ppm in grain. No significant concentration of these residues
occurred when the corn grain was processed by either wet or dry milling
procedures.
For soybean, flufenacet was applied as a preplant broadcast
treatment that was incorporated to a depth of approximately 2 inches or
as a preemergent broadcast treatment made within 1 day of planting the
soybean crop. The maximum residues detected were 0.10 ppm in seed, 1.20
ppm in green forage, and 9.75 ppm in dry hay.
B. Toxicological Profile
1. Acute toxicity. i. Technical grade flufenacet has a low to
moderate order of toxicity in rats by the oral route of exposure. The
acute oral LD50 was 1,617 milligrams/kilogram (mg/kg) for
males and 589 mg/kg for females.
ii. A dermal toxicity study on technical grade flufenacet revealed
low acute toxicity to rats. The dermal LD50 for both sexes
was >2,000 mg/kg, the highest dose tested.
iii. An acute inhalation study on technical grade flufenacet showed
low toxicity in rats with a 4-hour liquid aerosol LC50 for
males and females of >3,740 mg/m3 air, the highest
concentration tested.
iv. An eye irritation study on technical grade flufenacet in
rabbits showed minimal irritation to the
[[Page 13706]]
conjunctiva completely reversible within 7 days.
v. A dermal irritation study on technical grade flufenacet in
rabbits did not produced any irritation.
vi. Skin sensitization studies on technical grade flufenacet in
guinea pigs have produced equivocal results. A skin sensitization
potential was exhibited under the conditions of a maximization test,
whereby, there was no skin sensitization potential when tested by the
Buehler Topical Closed Patch Technique.
2. Genotoxicty. Flufenacet was negative for mutagenic/genotoxic
effects in a gene mutation/in vitro assay in bacteria, a gene mutation/
in vitro assay in Chinese hamster lung fibroblasts cells, a
cytogenetics/in vitro assay in Chinese hamster ovary cells, a
cytogenetics/in vivo mouse micronucleus assay, and an in vitro
unscheduled DNA synthesis assay in primary rat hepatocytes.
3. Reproductive and developmental toxicity. i. A two-generation rat
reproduction study with a parental systemic no observed adverse effect
level (NOAEL) of 20 ppm (1.4 mg/kg/day in males and 1.5 mg/kg/day in
females) and a reproductive NOAEL of 20 ppm (1.3 mg/kg/day) and a
parental systemic lowest observed adverse effect level (LOAEL) of 100
ppm (7.4 mg/kg/day in males and 8.2 mg/kg/day in females) based on
increased liver weight in F1 females and hepatocytomegaly in
F1 males and a reproductive LOAEL of 100 ppm (6.9 mg/kg/day)
based on increased pup death in early lactation (including cannibalism)
for F1 litters and the same effects in both F1
and F2 pups at the high dose level of 500 ppm (37.2 mg/kg/
day in F1 males and 41.5 mg/kg/day in F1 females,
respectively).
ii. A rat developmental study with a maternal NOAEL of 25 mg/kg/day
and with a maternal LOAEL of 125 mg/kg/day based on decreased body
weight gain initially and a developmental NOEL of 25 mg/kg/day and a
developmental LOAEL of 125 mg/kg/day based on decreased fetal body
weight, delayed development (mainly delays in ossification in the
skull, vertebrae, sternebrae, and appendages), and an increase in the
incidence of extra ribs.
iii. A rabbit developmental study with a maternal NOAEL of 5 mg/kg/
day and a maternal LOAEL of 25 mg/kg/day based on histopathological
finds in the liver and a developmental NOAEL of 25 mg/kg/day and a
developmental LOAEL of 125 mg/kg/day based on increased skeletal
variations.
4. Subchronic toxicity. i. A 84-day rat feeding study with a NOAEL
less than 100 ppm (6.0 mg/kg/day) for males and a NOAEL of 100 ppm (7.2
mg/kg/day) for females and with a LOAEL of 100 ppm (6.8 mg/kg/day) for
males based on suppression of thyroxine (T4) level and a LOAEL of 400
ppm (28.8 mg/kg/day) for females based on hematology and clinical
chemistry findings.
ii. A 13-week mouse feeding study with a NOAEL of 100 ppm (18.2 mg/
kg/day for males and 24.5 mg/kg/day for females) and a LOAEL of 400 ppm
(64.2 mg/kg/day for males and 91.3 mg/kg/day for females) based on
histopathology of the liver, spleen and thyroid.
iii. A 13-week dog dietary study with a NOAEL of 50 ppm (1.70 mg/
kg/day for males and 1.67 mg/kg/day for females) and a LOAEL of 200 ppm
(6.90 mg/kg/day for males and 7.20 mg/kg/day for females) based on
evidence that the bio-transformation capacity of the liver has been
exceeded, (as indicated by an increase in LDH, liver weight, ALK and
hepatomegaly), globulin and spleen pigment in females, decreased T4 and
ALT values in both sexes, decreased albumin in males, and decreased
serum glucose in females.
iv. A 21-day rabbit dermal study with the dermal irritation NOAEL
of 1,000 mg/kg/day for males and females and a systemic NOAEL of 20 mg/
kg/day for males and 150 mg/kg/day for females and a systemic LOAEL of
150 mg/kg/day for males and 1,000 mg/kg/day for females based on
clinical chemistry data (decreased T4 and FT4 levels in both sexes) and
centrilobular hepatocytomegaly in females.
5.Chronic toxicity. i. A 1-year dog chronic feeding study with a
NOAEL was 40 ppm (1.29 mg/kg/day in males and 1.14 mg/kg/day in
females) and a LOAEL of 800 ppm (27.75 mg/kg/day in males and 26.82 mg/
kg/day in females) based on increased alkaline phosphatase, kidney, and
liver weight in both sexes, increased cholesterol in males, decreased
T2, T4 and ALT values in both sexes, and increased incidences of
microscopic lesions in the brain, eye, kidney, spinal cord, sciatic
nerve and liver.
ii. A rat chronic feeding/carcinogenicity study with a NOAEL less
than 25 ppm (1.2 mg/kg/day in males and 1.5 mg/kg/day in females) and a
LOAEL of 25 ppm (1.2 mg/kg/day in males and 1.5 mg/kg/day in females)
based on methemoglobinemia and multi-organ effects in blood, kidney,
spleen, heart, and uterus. Under experimental conditions the treatment
did not alter the spontaneous tumor profile.
iii. In a mouse carcinogenicity study the NOAEL was less than 50
ppm (7.4 mg/kg/day) for males and the NOAEL was 50 ppm (9.4 mg/kg/day)
for females and the LOAEL was 50 ppm (7.4 mg/kg/day) for males and the
LOAEL was 200 ppm (38.4 mg/kg/day) for females based on cataract
incidence and severity. There was no evidence of carcinogenicity for
flufenacet in this study.
6. Animal metabolism. A rat metabolism study showed thatradio-
labeled flufenacet was rapidly absorbed and metabolized by both sexes.
Urine was the major route of excretion at all dose levels and smaller
amounts were excreted via the feces.
7. Metabolite toxicology. A 55-day dog study withsubcutaneous
administration of thiadone (flufenacet metabolite) supports the
hypothesis that limitations in glutathione interdependent pathways and
antioxidant stress result in metabolic lesions in the brain and heart
following flufenacet exposure.
8. Endocrine disruption. EPA is required to develop ascreening
program to determine whether certain substances (including all
pesticides and inerts) may have an effect in humans that is similar to
an effect produced by a naturally occurring estrogen, or such other
effect. The Agency is currently working with interested stakeholders,
including other government agencies, public interest groups, industry
and research scientists in developing a screening and testing program
and a priority setting scheme to implement this program. Congress has
allowed 3 years from the passage of FQPA (August 3, 1999) to implement
this program. At that time, EPA may require further testing of this
active ingredient and end use products for endocrine disrupter effects.
Based on the toxicological findings for flufenacet relating to
endocrine disruption effects, flufenacet should be considered as a
candidate for evaluation as an endocrine disrupter when the criteria
are established.
9. Other studies. i. An acute rat neurotoxicity study with a NOAEL
less than 75 mg/kg/day and a LOAEL of 75 mg/kg/day based on decreased
motor activity in males.
ii. A rat subchronic neurotoxicity study with a NOAEL of 120 ppm
(7.3 mg/kg/day in males and 8.4 mg/kg/day in females) and a LOAEL of
600 (38.1 mg/kg/day in males and 42.6 mg/kg/day in females) based on
microscopic lesions in the cerebellum/medulla and spinal cords.
iii. A rat developmental neurotoxicity dietary study established an
overall NOAEL for both dams and offspring of 17.5 ppm. A LOAEL of 80.8
ppm was established based on body weight and
[[Page 13707]]
feed consumption declines common to both dams and offspring as well as
developmental delays which were noted in the offspring (eye opening,
preputial separation). No evidence of specific neurobehavioral effects
in the offspring were observed at dietaryconcentrations of up to 404
ppm.
C. Aggregate Exposure
1. Dietary exposure. Flufenacet is an herbicide withcurrently
registered uses on corn and soybean. Section 18 emergency exemptions
for use on wheat have been approved in several states. Also, time
limited tolerances exist for inadvertent or indirect residues on
alfalfa, clover, and crop groups 15, 16 and 17. Tolerances are proposed
for use on Crop Group 1C, tuberous and corm vegetables, which includes
potatoes and sweet potatoes. There are no residential uses for
flufenacet, therefore aggregate exposure would consist of any potential
exposure to flufenacet residues in the registered and proposed crops
and in drinking water.
i. Food. Acute and Chronic dietary exposure assessments were
conducted using the Dietary Exposure Evaluation Model (DEEM[reg],
Version 7.76) from Exponent, Inc. and the 1994-1996, 1998 CSFII
consumption database. Dietary exposure values were compared to the
acute RfD of 0.083 milligrams/kilogram of body weight per day (mg/kg
bw/day) based on a LOEL from an acute neurotoxicity study in rats and a
900-fold uncertainty factor. The chronic RfD of 0.004 mg/kg bw/day is
based on a LOEL from a combined chronic toxicity/carcinogenicity study
in the rat with a 300-fold uncertainty factor.
The refined acute and chronic dietary risk assessments were
performed using anticipated residues for all registered and proposed
crops and crop groups. Adjustments were made to account for percent of
crop treated and processing factors where available. The Tier 2 acute
analysis resulted in the U.S. population using 0.00437 mg/kg bw/day or
5.2% of the acute RfD. The highest exposed subpopulation was non-
nursing infants at 0.00893 mg/kg bw/day utilized or 10.7% of the acute
RfD.
For the Tier 3 chronic analysis the U.S. population utilized
0.000087 mg/kg bw/day or 2.2% of the chronic RfD. The highest exposed
subpopulation was children 1-6 at 0.000179 mg/kg bw/day or 4.5% of the
chronic RfD.
ii. Drinking water. The EPA has calculated drinking waterlevel of
comparison (DWLOCs) for acute exposure to flufenacet in drinking water
as 2.87 ppm for the U.S. population and 813 ppb for children (1-6 years
old). The Agency's screening concentration in ground water (SCI-Grow)
model estimates peak levels of flufenacet and its metabolite thiadone
in groundwater to be 15.3 ppb. EPA's Pesticide Root Zone Model/Exposure
Analysis Modeling System (PRZM/EXAMS) estimates peak levels of
flufenacet and its metabolite thiadone in surface water to be 17 ppb.
EPA's acute drinking water levels of comparison are well above the
estimated exposures for flufenacet in water for the U.S. population and
the subgroup with highest estimated exposure.
The EPA has calculated the drinking water level of comparison for
chronic exposure to flufenacet in drinking water as 136 ppb for the
U.S. population assuming that an adult weighs 70 kg and consumes a
maximum of 2 liters of water per day. For children (1-6 years old), the
DWLOC was 37.7 ppb assuming that a child weighs 10 kg and consumes a
maximum of 1 liter of water per day. The drinking water estimated
concentration (DWECs) for groundwater (parent flufenacet and degradate
thiadone) calculated from modeling data is 0.03 ppb for chronic
concentrations which does not exceed the DWLOC of 37.7 ppb for children
(1-6 years old). The DWEC for surface water based on the computer
models PRZM 2.3 and EXAMS 2.97.5 was calculated to be 14.2 ppb for
chronic concentration (parent flufenacet and degradate thiadone) which
does not exceed the DWLOC of 37.7 ppb for children (1-6 years old). The
EPA has concluded that there is a reasonable certainty that no harm
will result from aggregate exposure to flufenacet residues.
2. Non-dietary exposure. There are no non-food uses of flufenacet
currently registered under the Federal Insecticide, Fungicide and
Rodenticide Act, as amended. No non-dietary exposures are expected for
the general population.
D. Cumulative Effects
Flufenacet is structurally a thiadiazole. EPA is not aware of any
other pesticides with this structure. For flufenacet, EPA has not yet
conducted a detailed review of common mechanisms to determine whether
it is appropriate, or how to include this chemical in a cumulative risk
assessment. After EPA develops a methodology to address common
mechanism of toxicity issues to risk assessments, the Agency will
develop a process (either as part of the periodic review of pesticides
or otherwise) to reexamine these tolerance decisions. Unlike other
pesticides for which EPA has followed a cumulative risk approach based
on a common mechanism of toxicity, flufenacet does not appear to
produce a toxic metabolite produced by other substances. For the
purposes of these tolerance actions; therefore, EPA has not assumed
that flufenacet has a common mechanism of toxicity with other
substances.
E. Safety Determination
1. U.S. population. Using the assumptions and data described above,
it is concluded that chronic dietary exposure to all registered and
proposed uses of flufenacet will utilize at most 2.2% of the chronic
RfD for the U.S. population. The acute dietary exposure assessment
results in the U.S. population utilizing 5.2% of the acute RfD. EPA
generally has no concern for exposures below 100% of the acute or
chronic reference dose. Drinking water levels of comparison based on
the dietary exposure are greater than the highly conservative drinking
water estimated concentrations as shown above. Therefore, there is a
reasonable certainty that no harm will occur to the U.S. population
from aggregate exposure (food and drinking water) to residues of
flufenacet.
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of flufenacet, EPA
considered data from developmental toxicity studies in the rat and
rabbit and a two-generation reproduction study in the rat. The
developmental toxicity studies are designed to evaluate adverse effects
on the developing organism resulting from pesticide exposure during
prenatal development to one or both parents. Reproduction studies
provide information relating to effects from exposure to the pesticide
on the reproductive capability of mating animals and data on systemic
toxicity. FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre- and post-natal toxicity and the
completeness of the data base unless EPA determines that a different
margin of safety will be safe for infants and children. Although there
is no indication of increased sensitivity to young rats or rabbits
following pre- and/or post-natal exposure to flufenacet in the standard
developmental and reproductive toxicity studies, an additional
developmental neurotoxicity study, which is not normally required, is
needed to access the susceptibility of the offspring in function/
neurological development. Therefore, EPA has required that a
developmental neurotoxicity study be conducted with flufenacet and a
threefold safety factor for children and infants will be used in the
aggregate dietary acute and chronic
[[Page 13708]]
risk assessment. Although there is no indication of additional
sensitivity to young rats or rabbits following pre- and/or post-natal
exposure to flufenacet in the developmental and reproductive toxicity
studies; the Agency concluded that the FQPA safety factor should not be
removed but instead reduced because:
i. There was no assessment of susceptibility of the offspring in
functional/neurological developmental and reproductive studies.
ii. There is evidence of neurotoxicity in mice, rats, and dogs.
iii. There is concern for thyroid hormone disruption.
Using the assumptions and data described in the aggregate exposure
section and the appropriate safety factors as discussed above it is
concluded that the most sensitive subpopulations of infants and
children have a reasonable certainty of no harm. For the chronic
assessment, the most sensitive subpopulation, children 1-6, uses 4.5%
of the chronic RfD. The acute assessment shows the most sensitive
subpopulation to be non-nursing infants at 10.7% of the acute RfD. The
calculated drinking water levels of comparison (DWLOCs) for children of
765 ppb (acute) and 38 ppb (chronic) are well above the conservative
drinking water estimated concentrations. Therefore, there is a
reasonable certainty that no harm will occur to infants and children
from aggregate exposure to potential residues of flufenacet in food and
drinking water.
F. International Tolerances
Maximum residue levels are established or proposed for countries of
the European Communities in the following commodities: Cereals at 0.5
ppm; corn at 0.5 ppm; potato at 0.1 ppm; sunflower at 0.05 ppm; soybean
at 0.05 ppm; animal meat at 0.05 ppm; animal edible offal's at 0.05
ppm; animal fat at 0.05 ppm; milk at 0.01 ppm; and eggs at 0.05 ppm.
[FR Doc. 03-6711 Filed 3-19-03; 8:45 am]
BILLING CODE 6560-50-S