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Fluroxypyr (Dow AgroSciences). January 15, 2003. Petition for pesticide tolerances. Federal Register.
http://www.epa.gov/fedrgstr/EPA-PEST/2003/January/Day-15/p848.htm
[Federal Register: January 15, 2003 (Volume 68, Number 10)]
[Notices]
[Page 2027-2032]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15ja03-43]
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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2002-0339; FRL-7285-1]
Fluroxypyr; Notice of Filing a Pesticide Petition to Establish a
Tolerance 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
fluroxypyr in or on various food commodities.
DATES: Comments, identified by docket ID number OPP-2002-0339, must be
received on or before February 14, 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: Joanne I. Miller, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 305-6224; e-mail address:
miller.joanne@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:
¥ Crop production (NAICS 111)
¥ Animal production (NAICS 112)
¥ Food manufacturing (NAICS 311)
¥ Pesticide manufacturing (NAICS 32532)
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
CONTACT.
B. How Can I Get Copies of this Document and Other Related Information?
1. Docket. EPA has established an official public docket for this
action under docket identification (ID) number OPP-2002-0339. 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
comments, access the index listing of the contents of the official
public docket, and to access those documents in the public docket that
are available electronically. Although not all docket materials may be
available electronically, you may still access any of the publicly
available docket materials through the docket facility identified in
Unit I.B.1. Once in the system, select ``search,'' then key in the
appropriate docket ID number.
Certain types of information will not be placed in the EPA Dockets.
Information claimed as CBI and other information whose disclosure is
restricted by statute, which is not included in the official public
docket, will not be available for public viewing in EPA's electronic
public docket. EPA's policy is that copyrighted material will not be
placed in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. To the extent
feasible, publicly available docket materials will be made available in
EPA's electronic public docket. When a document is selected from the
index list in EPA Dockets, the system will identify whether the
document is available for viewing in EPA's electronic public docket.
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified in Unit I.B. EPA intends to work towards
providing electronic access to all of the publicly available docket
materials through EPA's electronic public docket.
For public commenters, it is important to note that EPA's policy is
that public comments, whether submitted electronically or in paper,
will be made available for public viewing in EPA's electronic public
docket as EPA receives them and without change, unless the comment
contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. When EPA identifies a comment
containing copyrighted material, EPA will provide a reference to that
material in the version of the comment that is placed in EPA's
electronic public docket. The entire printed comment, including the
copyrighted material, will be available in the public docket.
Public comments submitted on computer disks that are mailed or
delivered to the docket will be transferred to EPA's electronic public
docket. Public comments that are mailed or delivered to the docket will
be scanned and placed in EPA's electronic public docket. Where
practical, physical objects will be photographed, and the photograph
will be placed in EPA's electronic public docket along with a brief
description written by the docket staff.
C. How and To Whom Do I Submit Comments?
You may submit comments electronically, by mail, or through hand
delivery/courier. To ensure proper receipt by EPA, identify the
appropriate docket ID number in the subject line on the first page of
your comment. Please ensure that your comments are submitted within the
specified comment period. Comments received after the close of the
comment period will be marked ``late.'' EPA is not required to consider
these late comments. If you wish to submit CBI or information that is
otherwise protected by statute, please follow the instructions in Unit
I.D. Do not use EPA Dockets or e-mail to submit CBI or information
protected by statute.
1. Electronically. If you submit an electronic comment as
prescribed in this unit, EPA recommends that you include your name,
mailing address, and an e-mail address or other contact information in
the body of your comment. Also include this contact information on the
outside of any disk
[[Page 2028]]
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-2002-0339. 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-2002-0339. 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-2002-0339.
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-2002-0339. Such deliveries are only accepted during the
docket's normal hours of operation as identified in Unit I.B.1.
D. How Should I Submit CBI to the Agency?
Do not submit information that you consider to be CBI
electronically through EPA's electronic public docket or by e-mail. You
may claim information that you submit to EPA as CBI by marking any part
or all of that information as CBI (if you submit CBI on disk or CD ROM,
mark the outside of the disk or CD ROM as CBI and then identify
electronically within the disk or CD ROM the specific information that
is CBI). Information so marked will not be disclosed except in
accordance with procedures set forth in 40 CFR part 2.
In addition to one complete version of the comment that includes
any information claimed as CBI, a copy of the comment that does not
contain the information claimed as CBI must be submitted for inclusion
in the public docket and EPA's electronic public docket. If you submit
the copy that does not contain CBI on disk or CD ROM, mark the outside
of the disk or CD ROM clearly that it does not contain CBI. Information
not marked as CBI will be included in the public docket and EPA's
electronic public docket without prior notice. If you have any
questions about CBI or the procedures for claiming CBI, please consult
the person listed under FOR FURTHER INFORMATION CONTACT.
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
notice.
7. To ensure proper receipt by EPA, be sure to identify the docket
ID number assigned to this action in the subject line on the first page
of your response. You may also provide the name, date, and Federal
Register citation.
II. What Action is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical in or on various food commodities under section 408
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that this petition contains data or information
regarding the elements set forth in FFDCA section 408(d)(2); however,
EPA has not fully evaluated the sufficiency of the submitted data at
this time or whether the data support granting of the petition.
Additional data may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: December 31, 2002.
Meredith F. Laws,
Acting Director, Registration Division, Office of Pesticide Programs.
Summary of Petition
The petitioner 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.
Dow AgroSciences
PP 9F6050
EPA has received a pesticide petition (9F6050) from Dow
AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268 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 part 180 by establishing
tolerances for combined residues of fluroxypyr 1-methylheptyl ester [1-
methylheptyl ((4-amino-3,5-dicloro-6-fluoro-2-pyridinyl)oxy)acetate or
fluroxypyr MHE]
and its metabolite fluroxypyr [((4-amino-3,5-dichloro-
6-fluoro-2-pyridinyl)oxy)acetic acid], free and conjugated, all
expressed as fluroxypyr, in or on the following raw
[[Page 2029]]
agricultural commodities at 0.02 parts per million (ppm) for kernels
plus cob with husk removed, and 1.0 ppm for forage. Tolerances for
residues of fluroxypyr MHE in or on field corn are being proposed in
support of this registration as follows: Grain, 0.02 ppm; forage, 1.0
ppm; and stover, 0.5 ppm. Tolerances for residues of fluroxypyr MHE in
or on sorghum as follows: Sorghum grain, 0.02 ppm; sorghum forage, 2.0
ppm; sorghum stover, 4.0 ppm. Tolerances for residues of fluroxypyr MHE
in or on grasses as follows: Grass forage, 120 ppm; grass hay, 160 ppm;
and grass silage, 100 ppm. Based on the above tolerances and an animal
feeding study, increased tolerances are also proposed for fluroxypyr
MHE and fluroxypyr, expressed as combined residues of total fluroxypyr,
in or on the following animal commodities: Milk of cattle, goats, hogs,
horses and sheep, 0.3 ppm; and kidney of cattle, goats, hogs, horses
and sheep, 1.5 ppm. EPA has determined that the petition contains data
or information regarding the elements set forth in section 408(d)(2) of
the FFDCA; 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.
A. Residue Chemistry
1. Plant metabolism. Fluroxypyr is a systemic herbicide that is
readily translocated and rapidly converts to the acid form following
absorption. Fluroxypyr moves readily throughout the plant via the
phloem (nutrient transporting) system and to a lesser extent through
the xylem (water-transporting). Fluroxypyr is distributed throughout
the entire plant, including the meristems and other developing plant
parts.
2. Analytical method. There is a practical method (GC with MS
detection) for measuring levels of fluroxypyr MHE in or on food with a
limit of detection that allows monitoring of food with residues at or
above the levels set for, the proposed tolerances. Fluroxypyr has been
tested through the FDAs Multi-residue Methodology, Protocols C, D. and
E. The results have been published in the FDA Pesticide Analytical
Manual, Volume I.
3. Magnitude of residues. The metabolism of fluroxypyr MHE in
plants and animals (goats and poultry) is adequately understood for the
purposes of these tolerances. Magnitudes of residue studies were
conducted for field corn, sweet corn, sorghum and grasses. A process
products study was not conducted in field corn since residues of
fluroxypyr MHE were not detected in corn grain at 5X the application
rate. In addition, processing of sorghum was not conducted since
residue data for flour are not required at this time because sorghum
flour is used exclusively in the U.S. as a component for drywall, and
not as either a human food or a feedstuff. No residues of fluroxypyr
are expected in root or leafy vegetable crops grown in rotation to
fluroxypyr-treated field corn, sweet corn, sorghum, and grasses, after
a 30-day plant-back interval at the maximum allowable label rate of 8
oz active ingredient/Acre. Field corn, sweet corn, sorghum and grasses
grown in rotation may contain low levels of fluroxypyr residues;
however, the tolerance values proposed for these crops will adequately
assure compliance with the labeled use patterns.
B. Toxicological Profile
1. Acute toxicity. Fluroxypyr MHE has low acute toxicity. The rat
oral LD50 is >5,000 milligrams/kilogram (mg/kg), the rabbit
dermal LD50 is >2,000 mg/kg, and the rat inhalation
LC50 is >1.0 mg/L (1,000 mg/cubic meter). In addition,
fluroxypyr MHE is not a skin sensitizer in guinea pigs, has no dermal
irritation in rabbits, and shows mild ocular irritation in rabbits. The
end use formulation of fluroxypyr MHE has a similar low acute toxicity
profile.
2. Genotoxicity. Short-term assays for genotoxicity consisting of a
bacterial reverse mutation assay (Ames test), an in vitro assay for
cytogenetic damage using the Chinese hamster ovary cells, an in vitro
chromosomal aberration assay using rat lymphocytes, and an in vivo
cytogenetic assay in the mouse bone marrow (micronucleus test) have
been conducted with fluroxypyr MHE. These studies show a lack of
genotoxicity. In addition, short-term assays for genotoxicity
consisting of an Ames metabolic activation test, possible induction of
point mutations at the HGPRT-Locus of Chinese hamster ovary cells, in
vivo and in vitro chromosomal aberrations in the Chinese hamster ovary
cells, unscheduled DNA synthesis in human embryonic cells, and an assay
in mouse lymphoma cells have been conducted with fluroxypyr. These
studies also show a lack of genotoxicity.
3. Reproductive and developmental toxicity. Developmental studies
in rats and rabbits were conducted with both fluroxypyr MHE and
fluroxypyr. Studies with fluroxypyr MHE showed maternal and fetal no
observed adverse effect levels (NOAELs) of 300 mg/kg/day (rat) and 500
mg/kg/day (rabbit). Studies with fluroxypyr showed NOAELs in the rat of
250 mg/kg/day for maternal effects and 500 mg/kg/day for fetal effects
and a NOAEL in the rabbit of 250 mg/kg/day for both maternal and fetal
effects. These studies show that fluroxypyr and fluroxypyr MHE are not
teratogenic nor will they interfere with in utero development. Two
multi-generation reproduction studies were conducted with fluroxypyr in
rats. The first in Wistar rats showed no effect on fertility or
reproductive performance and had a NOAEL of 500 mg/kg/day (highest dose
tested). The second study in Sprague-Dawley rats showed a parental
NOAEL for systemic effects of 100 mg/kg/day in male rats and 500 mg/kg/
day in female rats. The NOAEL for reproductive effects was 750 mg/kg/
day for males and 1,000 mg/kg/day for females (highest dose tested).
The NOAEL for neonatal effects was 500 mg/kg/day.
4. Subchronic toxicity. Fluroxypyr MHE showed a NOAEL of 1,000 mg/
kg/day in a 90-day rat dietary study and a 21-day rabbit dermal study.
Ninety-day feeding studies with fluroxypyr showed NOAELs of 80 mg/kg/
day (Wistar rats), 700 mg/kg/day (Fischer 344 rats), 1,342 mg/kg/day
(male mice), and 1,748 mg/kg/day (female mice). In a 4-week dietary,
range finding study with fluroxypyr in dogs, the NOAEL found was >50
mg/kg/day.
5. Chronic toxicity. Based on chronic testing with fluroxypyr in
the mouse, dog, and rat (two studies), a reference dose (RfD) of 0.8
mg/kg/day is proposed for fluroxypyr and fluroxypyr MHE. The RfD has
incorporated a 100-fold safety factor to the NOAEL found in the rat
chronic test. NOAELs found in the chronic dietary studies are as
follows: 150 mg/kg/day (dog), 300 mg/kg/day (mouse), 80 mg/kg/day
(Wistar rats), 100 mg/kg/day (male Fischer 344 rats), and 500 mg/kg/day
(female Fischer 344 rats).
6. Animal metabolism. Both fluroxypyr and fluroxypyr MHE have been
evaluated in rat metabolism studies. In summary, these studies show
that fluroxypyr MHE is rapidly hydrolyzed and the fate of the
hydrolysis products, fluroxypyr and 1-methylheptanol, are independent
of whether they were given as the ester or the acid. Fluroxypyr, per
se, was extensively absorbed and rapidly excreted principally unchanged
in the urine; 1-methylheptanol also was rapidly absorbed and rapidly
eliminated. Repeated administration of fluroxypyr MHE was not
associated with accumulation in tissues. Also, the metabolism and
pharmacokinetics of 1-methylheptanol are comparable to that of the
methylheptyl portion of fluroxypyr MHE.
7. Metabolite toxicology. Administration of fluroxypyr, as the
[[Page 2030]]
acid or methylheptyl ester, in a variety of toxicological studies has
produced similar effects. The principal response to sufficiently high
dosages, whether administered over the short-term or, in some cases,
over a lifetime, was nephrosis. Fluroxypyr is an organic acid that is
actively excreted into the urine by the kidney. Thus, the target organ
and dose response relationship for fluroxypyr toxicity is entirely
consistent with the data on the toxicokinetics of fluroxypyr.
Metabolism studies have shown that fluroxypyr MHE is rapidly and
completely hydrolyzed to fluroxypyr acid and methylheptanol.
8. Endocrine disruption. There is no evidence to suggest that
fluroxypyr and fluroxypyr MHE have an effect on any endocrine system.
C. Aggregate Exposure
1. Dietary exposure--Acute dietary exposure and risk. A Tier I
acute dietary exposure and risk assessment was conducted. Potential
dietary exposure and risk was estimated using DEEMTM
software (Dietary Exposure Evaluation Model, Version 7.075, Novigen
Sciences, Inc., Washington, DC). A deterministic analysis was conducted
by combining the distribution of single-day food consumption events
with residues assumed at tolerance levels for each commodity to obtain
a distribution of exposure. In this report, acute dietary risk was
assessed at the 95th percentile of exposure.
i. Food. Very conservative assumptions were made in this dietary
risk assessment. The dietary exposure assessment was based on all
commodities with tolerances for fluroxypyr established at 40 CFR
180.535 together with proposed tolerances for field corn, sweet corn,
grain sorghum, and forage grass and hay, including revised tolerances
for milk and meat. It was assumed that fluroxypyr residues were present
at tolerance or proposed tolerance levels and that 100% of the crops
were treated. The USDA food consumption data from 1989-92 were used by
DEEM in estimating acute dietary exposure. Acute dietary risk was
assessed using an acute RfD of 1.25 mg/kg/day, based on a maternal
NOAEL of 125 mg/kg/day from a rat developmental toxicity study and an
uncertainty factor of 100 (10X for interspecies extrapolation and 10X
for intraspecies variation). There was no indication of increased
susceptibility in young animals to prenatal or postnatal exposure to
fluroxypyr in the toxicology studies. Therefore, an FQPA additional
safety factor for infants and children was not included in this
assessment. Acute dietary exposure at the 95th percentile for females
13 to 50 years old is estimated at 0.004939 mg/kg/day, which occupies
0.4% of the acute RfD. Pregnant females are estimated to have acute
dietary exposure of 0.006582 mg/kg/day at the 95th percentile, which
occupies 0.53% of the acute RfD. Adverse effects are not expected for
exposures occupying 100% or less of the RfD. Therefore, acute dietary
exposure and risk are well within acceptable levels.
A chronic dietary assessment estimated that dietary exposure would
occupy only 0.4% of the RfD for the overall U.S. population and 1.3% of
the RfD for children 1 to 6 years of age, the population subgroup
estimated to be most highly exposed.
ii. Drinking water--Acute drinking water exposure and risk. There
are no established Maximum Contaminant Levels for residues of
fluroxypyr in drinking water and health advisory levels for fluroxypyr
in drinking water have not been established.
Potential drinking water concentrations of fluroxypyr were
estimated in ground water and surface water using the Screening
Concentration in Ground Water (SCI-GROW) and the Generic Expected
Environmental Concentration (GENEEC) models, respectively. Both GENEEC
and SCI-GROW are Tier I screening level models that use conservative
assumptions. SCI-GROW estimates pesticide concentrations in shallow,
highly vulnerable ground water. GENEEC simulates a 1 hectare by 2
meters deep edge of the field farm pond that receives pesticide runoff
from a treated 10 hectare field. The estimated concentration of
fluroxypyr in ground water according to SCI-GROW is 0.16 [mu]g/L. The
estimated peak concentration of fluroxypyr in surface water using
GENEEC is 20.88 [mu]g/L.
To calculate the Drinking Water Levels of Concern (DWLOC) for acute
exposure relative to an acute toxicity endpoint, the acute dietary
exposure (from the DEEM analysis) was subtracted from the acute RfD to
obtain the acceptable upper limit of fluroxypyr in drinking water for
acute exposure. DWLOCs were then calculated using default values for
adult female body weight (60 kg) and water consumption (2 L/day).
The upper-bound estimated fluroxypyr concentration in ground water
(0.16 [mu]g/L) and surface water (20.88 [mu]g/L) are substantially
below the acute DWLOCs of 37,352 [mu]g/L and 37,303 for females 13 to
50 years old and pregnant females, respectively. Aggregated acute
fluroxypyr exposure for pregnant females and females 13 to 50 years old
resulting from dietary exposure and upper-bound drinking water exposure
is well within acceptable limits of exposure and risk.
The chronic DWLOC for both the overall U.S. population and children
1 to 6 years of age was over 3,000-fold greater than residue levels in
surface water or ground water estimated by conservative screening-level
models. Therefore, chronic exposure and risk is expected to be well
within acceptable levels.
2. Non-dietary exposure. The proposed use of fluroxypyr on
residential turf presents the potential for non-occupational, non-
dietary (or residential) exposure. Transferable foliar residue data
from a fluroxypyr study on turf was used instead of default residue
values.
Post-application dermal exposure for adults and toddlers was
estimated for the day of application (day 0) since the exposure
potential is greatest at this time. Transferable residue of fluroxypyr
from turf was found to range from 0.03 to 0.74% (used as a high end
stimate) of the fluroxypyr applied and to dissipate with a half-life
ranging from 1.4 to 2.5 days.
Homeowners may be exposed to fluroxypyr during application to turf
and also may have dermal exposure due to post-application activity on
the treated turf.
Homeowner exposure during the application of fluroxypyr to turf
includes both dermal and inhalation exposure. Surrogate dermal and
inhalation exposure data from Pesticide Handlers Exposure Database
(PHED V1.1) was used in estimating applicator exposure. The PHED
surrogate data used to estimate exposure assumes residential applicator
attire to include short pants, short-sleeve shirt, and no gloves. The
applicator exposure estimate was based on a broadcast application using
a garden hose end sprayer. Applicator dermal and inhalation exposure
was estimated to be 0.0986 mg/kg/day and 0.00003 mg/kg/day,
respectively.
Adult post-application dermal exposure from treated turf on the day
of application was estimated to be 0.0172 mg/kg/day. The combined
dermal exposure from application along with post-application activity
is 0.1158 mg/kg/day (0.0986 mg/kg/day + 0.0172 mg/kg/day). Oral post-
application exposure is not expected for adults and was not included in
this assessment. The Margin of Exposure (MOE) for dermal exposure is
8,635 and for inhalation exposure 2,666,667. These MOEs are
substantially greater than 100, indicating that risk
[[Page 2031]]
from these potential exposures is well within an acceptable level.
Consistent with the scenario described above for the general adult
population, female adult homeowners may experience exposure to
fluroxypyr during application to turf as well as from post-application
exposure. Female applicator dermal and inhalation exposure was
estimated to be 0.115 mg/kg/day and 0.00004 mg/kg/day, respectively.
Additionally, female adults may also experience post-application dermal
exposure from treated turf on the day of application. Post-application
dermal exposure for females was estimated to be 0.0201 mg/kg/day. Since
dermal absorption is assumed to be 100% and since both dermal and
inhalation exposure are being evaluated against the same toxicity
endpoint, total potential exposure from fluroxypyr use on turf can be
estimated by simply adding the dermal and inhalation exposure. The
combined exposure is 0.13514 mg/kg/day (0.115 mg/kg/day + 0.00004 mg/
kg/day + 0.0201 mg/kg/day). Using a NOAEL of 125 mg/kg/day, the MOE is
calculated to be 925 (125 mg/kg/day / 0.13514 mg/kg/day). The MOE for
female adults as a result of potential dermal and inhalation exposure
from residential use of fluroxypyr on turf is well above 100,
indicating that risk is within acceptable levels.
Golfers may have dermal exposure to fluroxypyr due to post-
application activity on the treated turf. Dermal exposure for adult
golfers was estimated on the day of treatment (day 0) to provide a
high-end estimate of exposure. Exposure was estimated based on a
transfer coefficient of 500 cm2/hr (1) and an
exposure time of 4 hours. Exposure was estimated to be 0.001186 mg/kg/
day. A MOE of 843,170 was calculated based on an assumption of 100%
dermal absorption and a NOAEL of 1,000 mg/kg/day. Given a MOE of three
orders of magnitude greater than 100, risk is well within acceptable
levels.
Potential exposure for female golfers was estimated to be 0.001383
mg/kg/day. A MOE of 90,383 was calculated based on an assumption of
100% dermal absorption and a NOAEL of 125 mg/kg/day. The MOE is
substantially greater than 100, indicating that risk is well within
acceptable levels.
Toddlers may have exposure due to post-application activity on
treated turf. When a pesticide in liquid formulation is applied to
turfgrass, toddlers may experience post-application exposure through
dermal exposure and also through oral exposure due to hand-to-mouth
transfer of pesticide residue, ingestion of treated turfgrass and
incidental ingestion of soil from treated areas.
Toddler post-application dermal exposure from treated turf on the
day of application was estimated to be 0.0288 mg/kg/day. Oral exposure
due to hand-to-mouth transfer of residues was estimated to be 0.0011
mg/kg/day. Oral exposure due to ingestion of treated grass was
estimated to be 0.0019 mg/kg/day. Combined oral exposure from hand-to-
mouth transfer of residues and ingestion of treated grass is 0.0030 mg/
kg/day (0.0011 mg/kg/day + 0.0019 mg/kg/day). The MOE for dermal
exposure is 34,722 and oral exposure is 26,667, both of them well above
100, indicating that risk is well within acceptable levels.
Use of fluroxypyr on turf results in potential short-term
residential exposure for adults and children. Potential short-term
dietary and residential exposures were combined into aggregate MOE
values. Potential exposure through drinking water was not included in
the aggregate MOEs, but was evaluated in aggregate through use of a
DWLOC calculated for short-term exposure. The aggregate MOEs for adults
and toddlers ranged from 906 to 29,335, but all were well above 100,
indicating an adequate margin of safety. Additionally, the short-term
DWLOCs for toddlers and adults were over 3,000-fold greater than
potential fluroxypyr residues in drinking water predicted by
conservative screening level models. Therefore, aggregate short-term
exposure and risk for children and adults is expected to be well within
acceptable levels.
D. Cumulative Effects
The potential for cumulative effects of fluroxypyr MHE and
fluroxypyr and other substances that have a common mechanism of
toxicity is also considered. There is no reliable information to
indicate that toxic effects produced by fluroxypyr MHE and fluroxypyr
would be cumulative with those of any other pesticide chemical. Thus,
it is appropriate to consider only the potential risks of fluroxypyr
MHE and fluroxypyr in an aggregate exposure assessment.
E. Safety Determination
1. U.S. population. Acute dietary exposure for pregnant females to
residues of fluroxypyr from current and proposed uses was estimated to
occupy 0.53% of the acute RfD, indicating very little risk.
Additionally, the acute DWLOC was calculated to be over 1,700 fold
greater than potential fluroxypyr residue in drinking water predicted
by conservative screening level models.
Potential dietary and residential exposures were combined into an
aggregate MOE value. Those MOEs range from 906 to 29,335. The aggregate
MOEs are well above 100, indicating risk is well within acceptable
levels. Additionally, the DWLOCs were over 11,000-fold greater than
potential fluroxypyr residue in drinking water. Chronic dietary
exposure to residues of fluroxypyr from current and proposed uses was
estimated to occupy 0.4% of the RfD. The DWLOC was calculated to be
over 11,000 fold greater than potential fluroxypyr residue in drinking
water.
It is concluded that there is a reasonable certainty that no harm
will result to the general U.S. population, pregnant females or
developing young from acute aggregate, short-term or chronic aggregate
exposures to fluroxypyr residues from current and proposed uses.
2. Infants and children. FFDCA section 408 provides that EPA may
apply an additional safety factor for infants and children in the case
of threshold effects to account for prenatal and postnatal toxicity and
the completeness of the data base. Based on the current toxicological
data requirements, the data base for fluroxypyr MHE relative to
prenatal and postnatal effects for children is complete. There were no
indications of neurotoxicity and developmental toxicity was not
observed in the absence of maternal toxicity. It is concluded that
there is no indication of increased sensitivity of infants and children
relative to adults and that an additional FQPA safety factor is not
required.
The acute and short-term exposures were assessed for pregnant
females to evaluate the risk for developmental toxicity and it was
concluded that there was reasonable certainty of no harm from aggregate
acute or short-term exposures resulting from current and proposed uses
of fluroxypyr.
Toddlers may experience short-term dermal and oral exposure to
fluroxypyr as a result of post-application activities on treated
residential turf. Additionally, there is the potential for exposure to
fluroxypyr through residue in food and drinking water. Tier I
assessments were conducted to develop very conservative estimates of
potential exposure through residential, dietary and drinking water
pathways.
Potential dietary and residential exposures were combined into an
aggregate MOE value. The aggregate MOE was 5,120, well above 100,
indicating risk is well within acceptable
[[Page 2032]]
levels. Additionally, the DWLOC was over 3,000-fold greater than
potential fluroxypyr residue in drinking water.
Chronic dietary exposure to residues of fluroxypyr from current and
proposed uses was estimated to occupy 1.3% of the RfD for children 1 to
6 years old, the population subgroup predicted to be most highly
exposed. Additionally, the DWLOC was calculated to be over 3,000 fold
greater than potential fluroxypyr residue in drinking water predicted
by conservative screening level models.
Thus, based on the completeness and reliability of the toxicity
data and the conservative exposure assessment, it is concluded that
there is a reasonable certainty that no harm will result to infants and
children from acute dietary, short-term and chronic aggregate exposures
to fluroxypyr residues from current and proposed uses.
F. International Tolerances
There are no Codex maximum residue levels established for residues
of fluroxypyr MHE and fluroxypyr on any food or feed crop.
[FR Doc. 03-848 Filed 1-14-03; 8:45 am]
BILLING CODE 6560-50-S