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Trifloxystrobin (Bayer). November 14, 2001. Pesticide Petition to Establish Tolerances in or on several Food commodities. Federal Register.
http://www.epa.gov/fedrgstr/EPA-PEST/2001/November/Day-14/p28199.htm
[Federal Register: November 14, 2001 (Volume 66, Number 220)]
[Notices]
[Page 57074-57079]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14no01-79]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-1048; FRL-6806-6]
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 a
certain pesticide chemical in or on various food commodities.
DATES: Comments, identified by docket control number PF-1048, must be
received on or before December 14, 2001.
[[Page 57075]]
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket
control number PF-1048 in the subject line on the first page of your
response.
FOR FURTHER INFORMATION CONTACT: By mail: Cynthia Giles-Parker,
Registration Division (7505C), Office of Pesticide Programs,
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460; telephone number: (703) 305-7740; e-mail address:
giles-parker.cynthia@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:
------------------------------------------------------------------------
Examples of
Categories NAICS codes potentially
affected entities
------------------------------------------------------------------------
Industry 111 Crop production
112 Animal production
311 Food manufacturing
32532 Pesticide
manufacturing
------------------------------------------------------------------------
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 Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the
entry for this document under the ``Federal Register--Environmental
Documents.'' You can also go directly to the Federal Register listings
at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket control number PF-1048. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number PF-1048 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: opp-docket@epa.gov, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket control number PF-1048. Electronic comments may
also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want to Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
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 version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified 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
control 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.
[[Page 57076]]
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 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: October 30, 2001.
Peter Caulkins,
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 section 408(d)(3) of the FFDCA. The summary of the
petition was prepared by the petitioner and represents the view of the
petitioner. EPA is publishing the petition summary verbatim without
editing it in any way. 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 Corporation
0F6121
EPA has received a pesticide petition (0F6121) from Bayer
Corporation, 8400 Hawthorn Road, P.O. Box 4913, Kansas City, MO 64121-
0013 proposing, pursuant to section 408(d) of the FFDCA, 21 U.S.C.
346a(d), to amend 40 CFR part 180, by establishing a tolerance for
residues of trifloxystrobin in or on the raw agricultural commodities
(RACs) barley grain at 0.05 parts per million (ppm), straw at 0.05 ppm,
barley hay at 0.2 ppm; citrus fruits crop group at 0.3 ppm, citrus oil
at 7.0 ppm; corn grain at 0.05 ppm, corn forage at 0.05 ppm, corn
stover at 7.0 ppm; aspirated grain fractions at 0.1 ppm, popcorn grain
at 0.05 ppm, popcorn stover at 7.0 ppm; rice grain at 3.5 ppm, rice
straw at 7.5 ppm; tree nuts crop group at 0.05 ppm; stone fruits crop
group at 2.0 ppm; poultry (fat, kidney, liver, meat by-products, meat)
at 0.05 ppm; and pistachio at 0.05 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. The metabolism of trifloxystrobin in plants
(cucumbers, apples, wheat, sugar beets, and peanuts) is well
understood. Identified metabolic pathways are substantially similar in
plants and animals (goat, rat, and hen). EPA has determined that
trifloxystrobin parent and its metabolite CGA-321113 are the residue of
concern for tolerance setting purposes.
2. Analytical method. A practical methodology for detecting and
measuring levels of trifloxystrobin in or on raw agricultural
commodities has been submitted. The limit of detection (LOD) for each
analyte of this method is 0.08 ng injected, and the limit of
quantitation (LOQ) is 0.02 ppm. The method is based on crop specific
cleanup procedures and determination by gas chromotography with
nitrogen-phosphorus detection.
3. Magnitude of residues. Residue trials were performed for
trifloxystrobin on a full geography of citrus fruits crop group (with
oranges, lemons, and grapefruit as representative citrus fruit crops);
field corn; popcorn, and rice as representative crops from the cereal
grain group; tree nuts crop group including pistachio (with almonds and
pecans as representative nut crops); and stone fruits crop group (with
peaches, plums, tart and sweet cherries as representative stone fruit
crops). A study was conducted on indicator crops to assay for secondary
residues in rotational crops. A three-level ruminant and poultry study
was completed to determine the rate of residues of trifloxystrobin from
residues in animal feed to ruminant and poultry commodities.
B. Toxicological Profile
1. Acute toxicity. Studies conducted with the technical material of
trifloxystrobin:
Rat acute oral toxicity study with a LD50
>5,000 milligram/kilogram (mg/kg).
Mouse acute oral toxicity study with a LD50
>5,000 mg/kg.
Rabbit acute dermal toxicity study with a LD50
>2,000 mg/kg.
Rat acute dermal toxicity study with a LD50
>2,000 mg/kg.
Rat acute inhalation toxicity study with a LC50
>4.65 milligram/Liter (mg/L).
Rabbit eye irritation study showing slight irritation
(Category III).
Rabbit dermal irritation study showing slight irritation
(Category IV).
Guinea pig dermal sensitization study with the Buehler's
method showing negative findings.
Guinea pig dermal sensitization study with the
maximization method showing some positive findings.
2. Genotoxicity. No genotoxic activity is expected of
trifloxystrobin under in vivo or physiological conditions. The compound
has been tested for its potential to induce gene mutation and
chromosomal changes in 5 different test systems. The only positive
finding was seen in the in vitro test system ((CHO) Chinese hamster V79
cells) as a slight increase in mutant frequency at a very narrow range
(250-278 g/ml) of cytotoxic and precipitating concentrations
(compound solubility in water was reported to be 0.61 g/ml;
precipitate was visually noted in culture medium at 150 g/ml).
The chemical was found to be non-mutagenic in the in vitro systems.
Consequently, the limited gene mutation activity in the V79 cell line
is considered a nonspecific effect under non-physiological in vitro
conditions and not indicative of a real mutagenic hazard.
3. Reproductive and developmental toxicity. 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 on
trifloxystrobin relative to prenatal and postnatal effects for children
is complete.
In assessing the potential for additional sensitivity of infants
and children to residues of trifloxystrobin, data were considered from
teratogenicity studies in the rat and the rabbit and a 2-generation
reproduction studies in the rat. The teratogenicity studies are
designed to evaluate adverse effects on the developing embryo as a
result of chemical exposure during the period of organogenesis.
Reproduction studies provide information on effects from chemical
exposure on the reproductive capability of mating animals and systemic
and developmental toxicity from in utero exposure.
In the rat teratology study, reductions in body weight (bwt) gain
and food
[[Page 57077]]
consumption were observed in the dam at 100 mg/kg. No
teratogenic effects or any other effects were seen on pregnancy or
fetal parameters except for the increased incidence of enlarged thymus,
which is a type of variation, at 1,000 mg/kg. The developmental no
observed adverse effect level (NOAEL) was 100 mg/kg.
In the rabbit teratology study, body weight loss and dramatically
reduced food consumption were observed in the dam at 250 mg/
kg. No teratogenic effects or any other effects were seen on pregnancy
or fetal parameters except for the increase in skeletal anomaly of
fused sternebrae-3 and sternebrae-4 at the top dose level of 500 mg/kg.
This finding is regarded as a marginal effect on skeletal development
that could have resulted from the 40-65% lower food intake during
treatment at this dose level. The developmental NOAEL was 250 mg/kg.
In the 2-generation rat reproduction study, body weight gain and
food consumption were decreased at 750 ppm, especially in
females during lactation. Consequently, the reduced pup weight during
lactation (750 ppm) and the slight delay in eye opening
(1,500 ppm) are judged to be a secondary effect of maternal toxicity.
No other fetal effects or any reproductive changes were noted. The low
developmental NOAEL, 50 ppm (5 mg/kg), seen in this study was probably
due to the lack of intermediate dose levels between 50 and 750 ppm.
Based on an evaluation of the dose-response relationship for pup weight
at 750 ppm and 1,500 ppm, the NOAEL should have been nearly ten-fold
higher if such a dose was available.
Based on all these teratology and reproduction studies, the lowest
NOAEL for developmental toxicity is 5 mg/kg while the lowest NOAEL in
the subchronic and chronic studies is 2.5 mg/kg/day (from the rat
chronic study). Therefore, no additional sensitivity for infants and
children to trifloxystrobin is suggested by the data base.
4. Subchronic toxicity. In subchronic studies, several mortality
related changes were reported for the top dose in dogs (500 mg/kg) and
rats (800 mg/kg). At these dose levels, excessive toxicity has resulted
in body weight loss and mortality with the associated and non-specific
changes in several organs (such as atrophy in the thymus, pancreas,
bone marrow, lymph node, and spleen) which are not considered specific
target organs for the test compound. In the dog, specific effects were
limited to hepatocellular hypertrophy at 150 mg/kg and
hyperplasia of the epithelium of the gall bladder at 500 mg/kg. Target
organ effects in the rat were noted as hepatocellular hypertrophy
(200 mg/kg) and the related liver weight increase
(50 mg/kg). In the mouse, target organ effects included
single cell necrosis (300 mg/kg) and hypertrophy (1,050 mg/
kg) in the liver and extramedullary hematopoiesis (300 mg/
kg) and hemosiderosis in the spleen (1,050 mg/kg).
In general, definitive target organ toxicity, mostly in the liver,
was seen at high feeding levels of over 100 mg/kg for an extended
treatment period. At the lowest observed adverse effect level (LOAEL),
no serious toxicity was observed other than mostly non-specific effects
including a reduction in body weight and food consumption or liver
hypertrophy.
5. Chronic toxicity. The liver appears to be the major primary
target organ based on the chronic studies conducted in mice, rats, and
dogs. It was identified as a target organ in both the mouse and the dog
studies with trifloxystrobin. However, no liver effect was seen in the
chronic rat study which produced the lowest NOAEL of 2.5 mg/kg based on
reduced body weight gain and food consumption seen at higher dose
levels.
The compound did not cause any treatment-related increase in
general tumor incidence, any elevated incidence or rare tumors, or
shortened time to the development of palpable or rapidly lethal tumors
in the 18-month mouse and the 24-month rat studies. Dosages in both
studies were sufficient for identifying a cancer risk. In the absence
of carcinogenicity, a reference dose (RfD) approach is appropriate for
quantitation of human risks.
6. Animal metabolism. Trifloxystrobin is moderately absorbed from
the gastrointestinal tract of rats and is rapidly distributed.
Subsequent to a single oral dose, the half-life of elimination is about
2 days and excretion is primarily via bile. Trifloxystrobin is
extensively metabolized by the rat into about 35 metabolites, but the
primary actions are on the methyl ester (hydrolysis into an acid), the
methoxyimino group (O-demethylation), and the methyl side chain
(oxidation to a primary alcohol). Metabolism is dose dependent as it
was almost complete at low doses but only about 60% complete at high
doses.
In the goat, elimination of orally administered trifloxystrobin is
primarily via the feces. The major residues were the parent compound
and the acid metabolite (CA-321113) plus its conjugates. In the hen,
trifloxystrobin is found as the major compound in tissues and in the
excreta, but hydroxylation of trifluormethyl-phenyl moiety and other
transformations, including methyl ester hydrolysis and demethylation of
methoxyimino group, are also seen. In conclusion, the major pathways of
metabolism in the rat, goat, and hen are the same.
7. Metabolite toxicology. Metabolism of trifloxystrobin has been
well characterized in plants, soil, and animals. In plants and soil,
photolytically induced isomerization results in a few minor metabolites
not seen in the rat; however, most of the applied materials remained as
parent compound as shown in the apple and cucumber studies. All
quantitatively major plant and/or soil metabolites were also seen in
the rat. The toxicity of the major acid metabolite, CGA-321113 (formed
by hydrolysis of the methyl ester), has been evaluated in cultured rat
hepatocytes and found to be 20-times less cytotoxic than the parent
compound. Additional toxicity studies were conducted for several minor
metabolites, including (CGA-357261, CGA-373466, and NOA-414412, are not
mutagenic to bacteria and are of low acute toxicity (LD50
>2,000 mg/kg). In conclusion, the metabolism and toxicity profiles
support the use of an analytical enforcement method that accounts for
parent trifloxystrobin.
8. Endocrine disruption. CGA-279202 does not belong to a class of
chemicals known for having adverse effects on the endocrine system.
Developmental toxicity studies in rats and rabbits and reproduction
study in rats gave no indication that CGA-279202 might have any effects
on endocrine function related to development and reproduction. The
subchronic and chronic studies also showed no evidence of a long-term
effect related to the endocrine system.
C. Aggregate Exposure.
1. Dietary exposure--i. Acute and chronic dietary exposure
assessments were performed on the crops that are the subject of this
petition using field trial residue values on the citrus and stone fruit
crop groups, corn, rice, barley, and tree nuts crop group including
pistachio. In addition, established uses on sugar beets, almonds,
fruiting vegetable (crop group), pome fruit (crop group), cucurbits
(crop group), bananas, grapes, peanuts, potatoes, hops, and wheat were
included in the assessment. All residues were generated from field
trials conducted with a minimum pre-harvest interval (PHI) and maximum
application rate. In addition, if market share data were available,
residues were adjusted for the percent crop treated. The residues in
processed potatoes, sugar beets (molasses), tomatoes,
[[Page 57078]]
oranges (juice), apples (juice), corn, rice, wheat fractions, peanuts,
and grapes (juice) were adjusted using experimentally determined
processing factors generated from processing studies. For all other
processed fractions, United States Department of Agriculture (USDA)
default processing factors were utilized. Residues in animal
commodities were calculated from theoretical dietary burden
calculations and transfer factors obtained from livestock and poultry
feeding studies. Assessments were conducted utilizing the Dietary
Exposure Evaluation Model (DEEM TM) from Novigen Sciences and
the 1994-96 Continuing all population subgroups were compared to an
acute reference dose (aRfD) of 2.5 mg/kg/day based on a developmental
NOAEL in rabbits and a 100-fold uncertainty factor (UF). Although this
endpoint is applicable to females only in the strictest sense, the
developmental NOAEL was used for all populations due to the lack of a
suitable toxicological endpoint. Chronic exposure was compared to a
chronic RfD of 0.05 mg/kg/day based on a chronic toxicity study in dogs
and a 100-fold uncertainty factor. Both acute and chronic toxicological
endpoints were taken from (40 CFR part 180) (64 FR 51901) (FRL-6382-5)
dated September 27, 1999.
Both acute and chronic exposure was minimal in all population
subgroups. The acute results were obtained from a probabilistic, 1,000-
iteration Monte Carlo assessment. Acute exposure was expressed at the
9.9th percentile of exposure and ranged from 0.17% to 0.80%
of the aRfD with non-nursing infants (less than 1 year old) as the most
sensitive population subgroup (0.80%) of the RfD). The chronic exposure
assessment was conducted by taking the mean field trial residue values
and comparing to average daily consumption values. Chronic exposure
ranged from 0.2% to 1.2% of the chronic RfD and the most sensitive
population was non-nursing infants (less than 1 year old).
ii. Drinking water. Estimated surface drinking water concentrations
(SDWA): The generic expected environmental concentration (GENEEC)
estimated surface water concentrations for trifloxystrobin uses
contributed little to the overall exposure. These estimated
concentrations were not adjusted for the estimated market share or
percentage of use area. The highest day-56 estimated environmental
concentration (EEC) values were 0.27 parts per billion (ppb) provided
by the established trifloxystrobin turf use. According to EPA ``OPP's
Interim Approach for Addressing Drinking Water Exposure,'' the average
day-56 value is divided by 3 when correcting for overestimation of the
GENEEC model. EPA has accepted that the average day-56 EEC value is
divided by 6 in the case when the product is applied to turf and
accounts for the effects of grass/turf in decreasing runoff (EPA, 1998,
EPA-730-F-97-002, PB97-137806, page 15). This division by 6 was used to
calculate the potential exposure via surface water from the
trifloxystrobin turf application, 0.27 ppb/6 = 0.045 ppb.
Estimated ground water concentrations: The screening concentration
in ground water (SCI-GROW) estimated ground water concentrations for
trifloxystrobin uses also contributed little to the overall exposure.
The estimated concentrations were not adjusted for the estimated market
share or percentage of use area. In each use scenario, the
concentration of trifloxystrobin in ground water was predicted to be
below 1 part per trillion (ppt). The highest estimated concentration of
trifloxystrobin in ground water was 0.000859 ppb provided by the
trifloxystrobin turf use.
iii. Drinking water levels of concern--a. Acute exposure. Based on
the EPA's ``Interim Guidance for Conducting Drinking Water Exposure and
Risk Assessments'' document (drafted December 2, 1997), acute drinking
water levels of comparison (DWLOCacute ) were calculated for
trifloxystrobin. The lowest acceptable margin of exposure (MOE) for any
pesticide is 100. This value was used in the drinking water levels of
concern (DWLOC) calculations. Based on this analysis, the maximum
estimated trifloxystrobin surface water at peak day-0 (2.54 ppb) and
ground water (0.000859 ppb) concentrations, human drinking water
exposures do not exceed the calculated acute DWLOC values (g/
L: 24,800 to 87,325 ). Therefore, acute human drinking water exposures
to trifloxystrobin from the existing and newly proposed uses would not
exceed the exposure allowable by the risk cup. From the acute dietary
exposure analysis provided for the trifloxystrobin dietary assessment,
the DWLOCacute were calculated for CGA-321113. Based on this
analysis, the maximum estimated CGA-321113 in surface water at Peak
Day-0 (38.73 ppb) and ground water (4.944316 ppb) concentrations, human
drinking water exposures do not exceed the calculated acute DWLOC
values (g/L: 24800 to 87150). Therefore, acute human drinking
water exposures to CGA-321113 from the existing and newly proposed
trifloxystrobin uses would not exceed the exposure allowable by the
risk cup.
b. Chronic exposure. The chronic drinking water levels of
comparison (DWLOCchronic ) were calculated for
trifloxystrobin. The maximum estimated trifloxystrobin surface water
(0.09 ppb) and ground water (0.000859 ppb) concentrations do not exceed
the calculated chronic DWLOC values (g/L: 494 to 1747).
Therefore, chronic human drinking water exposures to the existing and
newly proposed trifloxystrobin uses would not exceed the exposure
allowable by the risk cup. From the chronic dietary exposure analysis
provided for the trifloxystrobin dietary assess, the chronic drinking
water levels of comparison (DWLOCchronic ) were calculated
for CGA-321113. Based on this analysis, the maximum estimated CGA-
321113 in surface water at Day-56/3 (12.24 ppb) and ground water (0.989
ppb) concentrations, human drinking water exposures do not exceed the
calculated chronic DWLOC values (g/L: 494 to 1745). Therefore,
chronic human drinking water exposures to the existing and newly
proposed trifloxystrobin uses would not exceed the exposure allowable
by the risk cup.
2. Non-dietary exposure. Non-dietary exposure to trifloxystrobin is
considered negligible as the chemical is intended primarily for
commercial and agricultural use. Post-application re-entry exposure to
homeowners from professional use on residential ornamentals is
considered negligible. For workers handling this chemical, acceptable
margins of exposure (in the range of thousands) have been obtained for
both acute and chronic scenarios.
D. Cumulative Effects
Considerations of a common mechanism of toxicity is not appropriate
at this time since there is no information to indicate that toxic
effects produced by trifloxystrobin would be cumulative with those of
any other types of chemicals. Furthermore, the oximinoacetate is a new
type of fungicide and no compound in this general chemical class
currently has significant market share. Consequently, aggregate risk is
the only potential exposure to trifloxystrobin.
E. Safety Determination
1. U.S. determination. To calculate acute aggregate risk, high-end
exposures from food and drinking water sources are compared to the
acute PAD. Exposure to trifloxystrobin residues and the free form of
its acid metabolite, CGA-321113 in food will occupy, <1% of the acute
PAD for females 13+ years
[[Page 57079]]
old (nursing). Acute dietary risk was calculated for females 13+ years
old because the endpoint upon which the acute PAD is based on
developmental effects. Estimated drinking water levels were calculated
using drinking water models (SCI-GROW and GENEEC), and the values are
considered overestimates due to the conservative assumptions built into
the models. Estimated concentrations for trifloxystrobin residues in
surface and ground water are lower than EPA's DWLOCs. Therefore, it is
not expected that acute aggregate risk to trifloxystrobin residues from
acute food and drinking water sources will exceed EPA's level of
concern for acute aggregate risk.
Exposure to trifloxystrobin and the free form of its acid
metabolite, CGA-321113 residues in food will occupy less than 0.5% of
the chronic PAD for adult population subgroups (females 13+/nursing)
and no more than 2.0% of the chronic PAD for infant/children subgroups
(highest subgroup: non-nursing infants). Estimated concentrations of
trifloxystrobin residues in surface and ground water are lower than
EPA's DWLOCs. Estimated drinking water levels were calculated using
drinking water models, and the values are considered overestimates due
to the conservative assumptions built into the models. EPA has
previously determined chronic residential exposure of trifloxystrobin
is not expected. The established and pending uses of trifloxystrobin
when combined in a chronic aggregate risk assessment for food, water,
and residential sources will not exceed EPA's level of concern for
chronic aggregate risk. Bayer concludes that there is a reasonable
certainty that no harm will result from aggregate exposure to
trifloxystrobin residue.
2. Infants and children. On June 21, 1999, EPA FQPA safety factor
committee determined the 10x safety factor for the protection of
infants and children should be removed for trifloxystrobin. The
Committee's rationale for removing the FQPA safety factor is as
follows:
i. The trifloxystrobin toxicology data base is complete for FQPA
assessment.
ii. There is no indication of increased susceptibility of rat or
rabbits to trifloxystrobin. In the development and reproductive
toxicity studies, effects in the fetuses/offspring were observed only
at or above treatment levels which resulted in evidence of parental
toxicity.
Using the same exposure assumptions as employed for the
determination in the general population, it has been calculated that
the percent of the RfD that will be utilized by aggregate exposure to
residues of trifloxystrobin is <2.0% for non-nursing infants (<1 year)
(the most impacted sub-population). Therefore, based on the
completeness and reliability of the toxicity data base and the
conservative exposure assessment, Bayer concludes that there is a
reasonable certainty that no harm will result to infants and children
from aggregate exposure to trifloxystrobin residues.
F. International Tolerances
No Codex MRLs have been established for residues of
trifloxystrobin.
[FR Doc. 01-28199 Filed 11-13-01; 8:45 am]
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