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Carfentrazone-ethyl (FMC). May 16, 1997. Pesticide Petition for Temporary Tolerances. Federal Register.
http://www.epa.gov/docs/fedrgstr/EPA-PEST/1997/May/Day-16/p12911.htm
[Federal Register: May 16, 1997 (Volume 62, Number 95)]
[Notices]
[Page 27040-27043]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16my97-66]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-732; FRL-5717-4]
Notice of Filing of Pesticide Petitions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the initial filing of pesticide
petitions proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by the docket control number PF-732, must
be received on or before June 16, 1997.
ADDRESSES: By mail submit written comments to: Public Information and
Records Integrity Branch, Information Resources and Services Division
(7506C), Office of Pesticides Programs, Environmental Protection
Agency, 401 M St., SW., Washington, DC 20460. In person bring comments
to: Rm. 1132, CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
Comments and data may also be submitted electronically by following
the instructions under ``SUPPLEMENTARY INFORMATION.'' No confidential
business information should be submitted through e-mail.
Information submitted as a comment concerning this document may be
claimed confidential by marking any part or all of that information as
``Confidential Business Information'' (CBI). CBI should not be
submitted through e-mail. Information marked as CBI will not be
disclosed except in accordance with procedures set forth in 40 CFR part
2. A copy of the comment that does not contain CBI must be submitted
for inclusion in the public record. Information not marked confidential
may be disclosed publicly by EPA without prior notice. All written
comments will be available for public inspection in Rm. 1132 at the
address given above, from 8:30 a.m. to 4 p.m., Monday through Friday,
excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: By mail: Joanne Miller, PM 23,
Registration Division (7505C), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location and telephone number: Rm. 237, CM #2, 1921 Jefferson
Davis Hwy, Arlington, VA 22202, 703-305-6224, e-mail:
miller.joanne@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA has received pesticide petitions as
follows proposing the establishment and/or amendment of regulations for
residues of certain pesticide chemicals in or on various food
commodities under section 408 of the Federal Food, Drug, and Comestic
Act (FFDCA), 21 U.S.C. 346a. EPA has determined that these petitions
contain 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 supports granting of
the petition. Additional data may be needed before EPA rules on the
petition.
The official record for this notice of filing, as well as the
public version, has been established for this notice of filing under
docket control number [PF-732] (including comments and data submitted
electronically as described below). A public version of this record,
including printed, paper versions of electronic comments, which does
not include any information claimed as CBI, is available for inspection
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The official record is located at the address in
``ADDRESSES'' at the beginning of this document.
Electronic comments can be sent directly to EPA at:
opp-docket@epamail.epa.gov
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption. Comment and data
will also be accepted on disks in Wordperfect 5.1 file format or ASCII
file format. All comments and data in electronic form must be
identified by the docket number [PF-732] and appropriate petition
number. Electronic comments on this notice may be filed online at many
Federal Depository Libraries.
List of Subjects
Environmental protection, Agricultural commodities, Food additives,
Feed additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: May 7, 1997.
James Jones,
Acting Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
Petitioner summaries of the pesticide petitions are printed below
as required by section 408(d)(3) of the FFDCA. The summaries of the
petitions were prepared by the petitioners and represent the views of
the petitioners. EPA is publishing the petition summaries verbatim
without editing them 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.
FMC Corporation
PP 6G4615
EPA has received a pesticide petition (PP 6G4615) from FMC
Corporation, 1735 Market St., Philadelphia, PA 19103, 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 a
temporary tolerance for the combined residue of the herbicide
carfentrazone-ethyl (ethyl--2-dichloro-5-[4-(difluoromethyl)-
4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-
propanoate) and its major wheat metabolites: carfentrazone-ethyl
chloropropionic acid (, 2-dichloro-5-[4-difluoromethyl)-4,5-
dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic
acid), 3-hydroxymethyl-F8426-chloropropionic acid (, 2-
dichloro-5-[4-difluoromethyl)-4,5-dihydro-3-hydroxymethyl-5-oxo-1H-
1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic acid) and 3-desmethyl-
F8426 chloropropionic acid (, 2-dichloro-5-[4-difluoromethyl)-
4,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic acid)
in or on wheat raw agricultural commodities: 0.2 ppm in or on wheat
hay, 0.2 ppm in or on wheat straw, 0.2 ppm in or on wheat grain; and
establishing tolerance for combined residues of the herbicide
carfentrazone-ethyl (ethyl--2-dichloro-5-[4-(difluoromethyl)-
4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzene-
propanoate) and its two major corn metabolites: carfentrazone-
[[Page 27041]]
ethyl chloropropionic acid (, 2-dichloro-5-[4-
difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-
fluorobenzenepropanoic acid), and 3-desmethyl-F8426 chloropropionic
acid (, 2-dichloro-5-[4-difluoromethyl)-4,5-dihydro-5-oxo-1H-
1,2,4-triazol-1-yl]-4-fluorobenzenepropanoic acid) in or on corn raw
agricultural commodities: 0.15 ppm in or on corn forage, 0.15 ppm in or
on corn fodder, 0.15 ppm in or on corn grain.
EPA has determined that the 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 supports granting of the petitions. Additional data
may be needed before EPA rules on the petitions. The proposed
analytical method is GC-MS and is available for enforcement purposes.
As required by section 408(d) of the FFDCA, as recently amended by
the Food Quality Protection Act (FQPA) FMC included in the petition a
summary of the petition and authorization for the summary to be
published in the Federal Register in a notice of the receipt of the
petition. The summary represents the views of FMC; EPA is in the
process of evaluating the petition. As required by section 408(d)(3)
EPA is including the summary as a part of this notice of filing. EPA
may have made minor edits to the summary for the purpose of clarity.
Carfentrazone-ethyl is a postemergent herbicide which controls a
broad spectrum of broadleaf weeds at very low field application rates.
Carfentrazone-ethyl is particularly effective on Velvetleaf (Abutilon
theophrasti), Russian Thistle (Salsola kali), Pigweeds (Amaranthus
spp.), Morningglories (Ipomea spp.), Lambsquarters (Chenopodium album)
and Black Nightshade (Solanum nigrum). It is also effective on
sulfonylurea-resistant populations of important weeds such as Kochia
(Kochia scoparia) and Russian Thistle (Salsola kali) and on
imidazolinone- or sulfonylurea-resistant populations of pigweeds.
Use site: Corn: Broadleaf weeds (including cocklebur,
lambsquarters, morningglories, pigweeds, nightshades and velevetleaf);
Wheat: Broadleaf weeds (including wild buckwheat, kochia,
lambsquarters, mustards, nightshades, pigweeds, Russian thistle and
waterhemp).
Use pattern: Carfentrazone-ethyl herbicide is applied postemergence
to young actively growing weeds that have emerged from the soil.
Typically, the crop has less than eight leaves, and the weeds are less
than four inches tall when the product is applied. Crops such as corn
and wheat are tolerant to the product at use rates which control
selected weeds. The product is mixed in water or liquid nitrogen
fertilizer used as the carrier. A nonionic surfactant or liquid
nitrogen fertilizer is mixed with the spray solution to enhance weed
control. Spray volumes range from 5-40 gallons per acre. Other
herbicides may be tank mixed with carfentrazone-ethyl to broaden the
weed control spectrum.
A. Residue Chemistry
1. Plant metabolism. The qualitative nature of the residues in
plants and animals is adequately understood. Residues of carfentrazone-
ethyl do not concentrate in the processed commodities. There are no
Codex maximum residue levels established for residues of carfentrazone-
ethyl on wheat, corn or soybeans.
2. Analytical method. There is a practical analytical method
available using GC-MS, for detecting and measuring levels of
carfentrazone-ethyl in or on food with a limit of detection that allows
monitoring of food with residues at or above the levels set in these
tolerances.
3. Magnitude of the residue-- i. Wheat. F8426 50DF was applied to
28 wheat trials in the major wheat growing regions of the United
States. Trials were conducted on both winter wheat (16 trials) and
spring wheat (12 trials). Forage samples had total residues ranging
from ND (<0.1 ppm) to 0.64 ppm. The maximum total residue in/on any hay
sample was 0.24 ppm. The maximum total residue found on any straw
sample was an estimated 0.05 ppm. No detectable residues (>0.01 ppm) of
carfentrazone-ethyl or any of its metabolites were found in/on any
grain sample.
No detectable residues (>0.01 ppm) of carfentrazone-ethyl or its
metabolites were found in any of the treated wheat grain or processed
commodities. Based on these results, there was no concentration of
carfentrazone-ethyl or its acid metabolites into any of the processed
parts.
ii. Corn. Twenty four field corn trials were conducted in the major
corn growing regions of the continental United States with F8426 50DF.
No quantifiable residues (>0.05 ppm) of carfentrazone-ethyl or any of
its metabolites were found in the analyses of the treated forage,
fodder and grain samples except for two forage samples which had
residues of 0.05 and 0.10 ppm. The maximum total residue in/on any corn
forage sample was 0.10 ppm and on any fodder and grain sample was an
estimated 0.01 ppm. No detectable residues of carfentrazone-ethyl or
its metabolites were found in any fraction of corn treated. Based on
the residue results, there was no concentration of carfentrazone-ethyl
and its metabolites into any of the processed parts.
4. Animal feeding. There is no need for tolerances in animal meat,
milk, poultry or eggs since there is no reasonable expectation of
residues in these materials. This is based on the results of cow
feeding and poultry metabolism studies, as well as the plant metabolism
and crop rotation studies. Transfer factors are extremely low and
maximum expected total residues in meat, milk, poultry and eggs would
be below the method limit of detection (LOD). The LOD of the methods
is, therefore, higher than any individual analyte in any of the
matrices. Based on this, since there is no expectation of finite
residues in meat, milk, poultry and eggs, no tolerances are being
proposed for these commodities. The proposed crop tolerance levels are
adequate to cover residues likely to be present from the proposed use
of carfentrazone-ethyl. Therefore, no special processing to reduce the
residues will be necessary.
B. Toxicological Profile
EPA has reviewed and accepted over 20 separate toxicology studies
in support of temporary tolerances for carfentrazone-ethyl; additional
studies have been submitted to EPA for review. Carfentrazone-ethyl is
not a carcinogen, developmental toxin or a mutagen and has low oral and
dermal toxicity to mammals. The following mammalian toxicity studies
have been conducted to support the tolerance of carfentrazone-ethyl:
A rat acute oral study with an LD50 of greater than
5,000 mg/kg(male) and 5,143 mg/kg (female).
A rat acute dermal LD50 of greater than 4,000 mg/kg.
A rat acute inhalation LC50 of greater than 5.09 mg/L/4
hour.
A primary eye irritation study in rabbits which showed minimal
irritation.
A primary dermal irritation study in rabbits which showed no
irritation.
A primary dermal sensitization study which showed no sensitization.
An acute neurotoxicity study in the rat with a systemic NOAEL of
500 mg/kg; the NOAEL for neurotoxicity was greater than 2,000 mg/kg
(highest dose tested).
A 28-day feeding study in the rat with a NOEL of 1,000 ppm (74.6
mg/kg/
[[Page 27042]]
day for males; 85.2 mg/kg/day for females).
A 90-day feeding study in the rat with a NOEL of 1,000 ppm (57.9
mg/kg/day for males; 72.4 mg/kg/day for females).
A 28-day feeding study in the mouse with a NOEL of 4,000 ppm (571
mg/kg/day) for males and a NOEL of 1,000 ppm (143 mg/kg/day) for
females.
A 90-day feeding study in the mouse with a NOEL of 4,000 ppm
(approximately 571 mg/kg/day).
A 90-day subchronic neurotoxicity study in the rat with a systemic
NOEL of 1,000 ppm (59.0 mg/kg/day for males; 70.7 mg/kg/day for
females); the neurotoxicity NOEL was greater than 20,000 ppm (1178.3
mg/kg/day for males; 1433.5 mg/kg/day for females) which was the
highest dose tested.
A 24-month chronic feeding/oncogenicity study in the rat with a
chronic toxicity NOEL of 200 ppm (9 mg/kg/day) in the male and 50 ppm
(3 mg/kg/day) in the female. There was no evidence of an oncogenic
response.
A 4-week range-finding study in dogs confirmed that the appropriate
route of administration was by capsule and the top dose selected for
the 3-month study was the limit dose of 1,000 mg/kg/day.
A 90-day feeding study in dogs with a NOEL of 150 mg/kg/day for
both males and females.
A 12-month feeding study in dogs with a NOEL of 50 mg/kg/day.
A mouse oncogenicity study with a carcinogenic NOEL greater than
7,000 ppm (greater than 1,090 mg/kg/day for males; greater than 1,296
mg/kg/day for females) based on no evidence of carcinogenicity at the
highest dose tested.
An oral teratology study in the rat with a maternal NOEL of 100 mg/
kg/day; the developmental NOAEL was greater than 1,250 mg/kg/day.
An oral teratology study in the rabbit with a maternal NOEL of 150
mg/kg/day; the fetal NOEL was greater than 300 mg/kg/day (highest dose
tested) since no fetal effects were observed.
A 2-generation reproduction study in the rat with a NOAEL for
systemic toxicity of 500 ppm (P1: 120 mg/kg/day for males and 137 mg/
kg/day for females; F1: 134 mg/kg/day for males and 146 mg/kg/day for
females); the reproductive NOEL was greater than 4,000 ppm (P1: greater
than 323 mg/kg/day for males and greater than 365 mg/kg/day for
females; F1: greater than 362 mg/kg/day for males and greater than 409
mg/kg/day for females) since reproductive parameters were not affected
at the highest dose tested in the study.
The weight of the evidence of the mutagenicity database including
the following is that carfentrazone-ethyl is not mutagenic.
Ames Assay: Negative.
Mouse Micronucleus Assay: Negative.
In vitro Chromosome Aberration - Negative with activation; Positive
without activation.
CHO/HGPRT Forward Mutation Assay - Negative.
Unscheduled DNA Synthesis - Negative.
C. Aggregate Exposure
For purposes of assessing the potential dietary exposure, a
preliminary dietary risk assessment was conducted based on the
Theoretical Maximum Residue Contribution (TMRC) from the tolerances for
carfentrazone-ethyl on soybeans at 0.1 ppm, wheat at 0.2 ppm and corn
(field) at 0.15 ppm. (The TMRC is a ``worse case'' estimate of dietary
exposure since it is assumed that 100 percent of all crops for which
tolerances are established are treated and that pesticide residues are
present at the tolerance levels.) At this time the dietary exposure to
residues of carfentrazone-ethyl in or on food will be limited to
residues on soybeans, wheat and corn. There are no other established US
tolerances for carfentrazone-ethyl, and there are no registered uses
for carfentrazone-ethyl on food or feed crops in the US. In conducting
this exposure assessment, the following very conservative assumptions
were made--100 percent of soybeans, wheat and corn will contain
carfentrazone-ethyl residues and those residues would be at the level
of the tolerance which result in an overestimate of human exposure.
Other potential sources of general population exposure to residues
of pesticides are residues in drinking water and exposure from non-
occupational sources. Studies have indicated that carfentrazone-ethyl
will not move into groundwater.
There is no expectation of non-occupational exposure from any other
source since the current registration application is the first for
carfentrazone-ethyl and is limited to commercial production of corn and
wheat. The potential for non-occupational exposure to the general
population is, thus, insignificant.
EPA is also required to consider the potential for cumulative
effects of carfentrazone ethyl and other substances that have a common
mechanism of toxicity. EPA consideration of a common mechanism of
toxicity is not appropriate at this time since EPA does not have
information to indicate that toxic effects produced by carfentrazone-
ethyl would be cumulative with those of any other chemical compounds;
thus only the potential risks of carfentrazone-ethyl are considered in
this exposure assessment.
Chronic dietary effects. Based on the available toxicity data, FMC
believes that the Reference Dose (RfD) for carfentrazone-ethyl is 0.03
milligrams(mg)/kilogram(kg)/day. The RfD for carfentrazone-ethyl is
based on the chronic feeding/oncogenicity study in rats with a
threshold No-Observed Effect Level (NOEL) of 3 mg/kg/day and an
uncertainty factor of 100. EPA recently proposed a tiered approach to
estimate acute dietary exposure. The methods proposed by the EPA were
reviewed and supported by the FIFRA scientific advisory panel (SAP,
1995). EPA's Tier 1 method is based on the assumption that residue
concentrations do not vary. The analysis assumes that all residues have
the same magnitude, typically the highest field trial residue or
tolerance value. This value is assumed for all points along the
consumption distribution, resulting in a distribution of dietary
exposure.
For the acute analysis for carfentrazone-ethyl, a Tier 1 analysis
was conducted for the overall US population, infants and children 1 to
6 years of age. The analysis incorporated anticipated residue estimates
of 0.1 ppm for soybeans, wheat and corn including sweet and pop corn. A
NOEL of 3 mg/kg /day with a 100-fold uncertainty factor was used in the
calculation. This NOEL was derived from the chronic rat feeding study
and represents an extremely excessive worst case scenario. The
following margins of exposure (MOE) were calculated (margins of
exposure of 100 or more are considered satisfactory):
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Population Group Margin of Exposure
------------------------------------------------------------------------
US Population 3516
Infants 1804
Children 1 to 6 2057
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These MOEs show that there is no acute dietary risk from
carfentrazone-ethyl. Using the Guidelines for Carcinogen Risk
Assessment, carfentrazone-ethyl should be classified as Group ``E'' for
carcinogenicity -- no evidence of carcinogenicity -- based on the
results of carcinogenicity studies in two species. There was no
evidence of carcinogenicity in an 18-month feeding study in mice and a
2-year feeding study in rats at the dosage levels tested. The doses
tested are adequate for identifying a cancer risk. Thus, a cancer risk
assessment is not necessary. Using
[[Page 27043]]
the conservative exposure assumptions described and based on the
completeness and reliability of the toxicity data, the aggregate
exposure to carfentrazone-ethyl will utilize 0.61 percent of the RfD
for the US population. EPA generally has no concern for exposures below
100 percent of the RfD. Therefore, based on the completeness and
reliability of the toxicity data and the conservative exposure
assessment, FMC believes that there is a reasonable certainty that no
harm will result from aggregate exposure to residues of carfentrazone-
ethyl, including all anticipated dietary exposure and all other non-
occupational exposures.
D. Determination of Safety for Infants and Children
In assessing the potential for additional sensitivity of infants
and children to residues of carfentrazone-ethyl, EPA considers data
from developmental toxicity studies in the rat and rabbit and the 2-
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.
Reproduction studies provide information relating to effects on the
reproductive capacity of males and females exposed to the pesticide.
Developmental toxicity was not observed in developmental toxicity
studies using rats and rabbits. In these studies, the rat and rabbit
maternal NOELs were 100 mg/kg/day and 150 mg/kg/day, respectively. The
developmental NOEL for the rabbit was greater than 300 mg/kg/day which
was the highest dose tested and for the rat was 600 mg/kg/day based on
increased litter incidences of thickened and wavy ribs. These two
findings are not considered adverse effects of treatment but related
delays in rib development which are generally believed to be
reversible. In a 2-generation reproduction study in rats, no
reproductive toxicity was observed under the conditions of the study at
4,000 ppm which was the highest dose tested. 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 pre-and post-natal
toxicity and the completeness of the database. Based on the current
toxicological data requirements, the database relative to pre- and
post-natal effects for children is complete and an additional
uncertainty factor is not warranted. Therefore, the RfD of 0.03 mg/kg/
day is appropriate for assessing aggregate risk to infants and
children. Using the conservative exposure assumptions described above,
the percent of the RfD that will be utilized by aggregate exposure to
residues of carfentrazone-ethyl for non-nursing infants (<1 year old)
would be 0.38 percent and for children 1-6 years of age would be 1.56
percent (the most highly exposed group). Based on the completeness and
reliability of the toxicity data and the conservative exposure
assessment, FMC believes that there is a reasonable certainty that no
harm will result to infants and children from aggregate exposure to the
residues of carfentrazone-ethyl including all anticipated dietary
exposure.
E. Estrogenic Effects
No specific tests have been conducted with carfentrazone-ethyl to
determine whether the pesticide may have an effect in humans that is
similar to an effect produced by a naturally occurring estrogen.
[FR Doc. 97-12911 Filed 5-15-97; 8:45 am]
BILLING CODE 6560-50-F