FLUORIDE ACTION NETWORK PESTICIDE PROJECT
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Sulfentrazone (FMC). November
6, 1996.
Pesticide Tolerance Petition for residues in or on Soybeans. Federal Register.
http://www.epa.gov/fedrgstr/EPA-PEST/1996/November/Day-06/pr-896DIR/pr-896.html
Federal Register: November 6, 1996 (Volume 61, Number 216)] [Notices]
[Page 57420-57423]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
ENVIRONMENTAL PROTECTION AGENCY
[PF-670; FRL-5571-4]
Pesticide Tolerance Petition; Notice of Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
SUMMARY: This notice is a summary of a pesticide petition proposing the establishment
of a regulation for residues of sulfentrazone in or on soybeans.
DATES: Comments, identified by the docket number [PF-670], must be received
on or before, December 6, 1996.
ADDRESSES: By mail, submit written comments to Public Response and Program Resources Branch, Field Operations Division (7506C), Office of Pesticide 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 22202. Comments and data may also be submitted electronically by sending electronic mail (e-mail) to: 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. Comments and data will also be accepted on disks in WordPerfect in 5.1 file format or ASCII file format. All comments and data in electronic form must be identified by the docket number [PF-670]. Electronic comments on this proposed rule may be filed online at many Federal Depository Libraries. Additional information on electronic submissions can be found below in this document.
Information submitted as a comments 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 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: Joanne Miller (PM23) Rm., 237, CM #2, 1921 Jefferson Davis Highway, Arlington, VA. 703-305-6224, e-mail: miller.joanne@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA has received a pesticide petition (PP 4F4407)
from FMC Corporation, 1735 Market Street, Philadelphia, PA 19103, proposing
pursuant to section 408(d) of the Federal Food, Drug and Cosmetic Act (FFDCA),
21 U.S.C. section 346a(d), to amend 40 CFR part 180 by establishing a tolerance
for residues of the herbicide sulfentrazone (N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-
methyl-5-oxo-lH-1,2,4-triazol-1-yl]phenyl]-methanesulfonamide in or on the raw
agricultural commodity soybeans at 0.05 ppm and rotational crop tolerances in
cereal grains from 0.1 to 0.5 ppm. The proposed analytical method is gas chromatography
with electron detection. Pursuant to section 408(d)(2)(A)(I) of the FFDCA, as
amended, FMC Corporation has submitted the following summary of information,
data and arguments in support of their pesticide petition. This summary was
prepared by FMC Corporation and EPA has not fully evaluated the merits of the
petition. EPA edited the summary to clarify that the conclusions and arguments
were the petitioner's and not necessarily EPA's and to remove certain extraneous
material.
I. FMC Petition Summary
workers and the population in general far exceed the EPA required level of 100.
The following mammalian toxicity studies have been conducted to support the tolerance of sulfentrazone: A rat acute oral study with an LD<INF>50 of 3,034 mg/kg (male) and 2,689 mg/kg (female).
A rabbit acute dermal LD<INF>50 of >2,000 mg/kg. A rat acute inhalation LC<INF>50 of >4.13 mg/L. A primary eye irritation study in the rabbit which showed mild irritation.
A primary dermal irritation study which showed no irritation. A primary dermal sensitization study which showed no sensitization. An acute neurotoxicity study with a No-Observed Effect Level (NOEL) of 250 mg/kg and no neuropathological findings at any dose. A 28-day feeding study in the rat with a NOEL of 1,000 ppm based on hematology effects.
A 90-day feeding study in the rat with a NOEL of 1,000 ppm based on hematology findings.
A 28-day feeding study in the mouse with a NOEL of 800 ppm based on effects on hematology parameters.
A 90-day feeding study in the mouse with a NOEL of 300 ppm based on hematology parameters.
A 90-day subchronic neurotoxicity study in the rat with a neurotoxicity and overall NOEL of 500 ppm; no histopathological effects on the peripheral or central nervous system were observed. A 24-month chronic feeding/oncogenicity study in the rat with an overall NOEL of 600 ppm in females and 1,000 ppm in males based on hematology effects and reduced body weights. There was no evidence of an oncogenic response.
A 4 week range-finding study in dogs with a NOEL of 900 ppm based on hematology effects.
A 90-day feeding study in dogs with a NOEL of 300 ppm based on liver histopathology.
A 12-month feeding study in dogs with a NOEL of 800 ppm based on hematology
effects and microscopic liver changes. A mouse oncogenicity study with a
NOEL of 600 ppm based on decreased hemoglobin. There was no evidence of
oncogenicity. An oral teratology study in the rat with a maternal NOEL of
25 mg/ kg/day based on body weight effects and a fetal NOEL of 10 mg/kg/day
based on reduced body weights and delayed skeletal effects at higher doses.
A supplemental teratology study conducted to test for cardiac effects at
the request of the EPA did not reveal any significant effects on fetal cardiac
development. A dermal teratology study in the rat with a maternal NOEL of
250 mg/kg/day and a fetal NOEL of 100 mg/kg/day based on an increase in
fetal and litter incidence of skeletal effects. An oral teratology study
in the rabbit with a maternal and fetal NOEL of 100 mg/kg/day based on decreased
body weights for the does and fetal effects at higher doses.
A two generation reproduction study in the rat with a NOEL for systemic
and reproductive/developmental parameters of 200 ppm. Male fertility in
the Fl generation was reduced at higher doses; litter size, pup survival
and pup bodyweight for both generations were also effected at higher doses.
A supplemental rat reproduction study with a NOEL for reproductive parameters
of 200 ppm.
Ames Assay: Negative; Mouse lymphoma: Negative with activation, equivocal
without activation.
Mouse Micronucleus Assay: Negative. 3. Threshold effects--chronic effects.
Based on the available chronic toxicity data, FMC believes the Reference
Dose (RfD) for sulfentrazone should be 0.05 mg/kg/day. The RfD for sulfentrazone
is based on a multigeneration reproduction study in rats with a threshold
No-observed Effect Level (NOEL) of 14 mg/kg/day and an uncertainty factor
of 100, with an additional modifying factor of 3 to account for the nature
of the effects.
Acute toxicity. 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 sulfentrazone, a Tier 1
analysis was conducted for the overall U.S. population, infants, children
1 to 6 years of age, females 13 years and older, and males 13 years and
older. Using the NOEL of 10 mg/kg/day derived from the oral teratology study
in rats, the following margins of exposure were calculated (Margins of exposure
of 100 or more are considered satisfactory):
Population Group Margin of Exposure
U.S. Population................................ 2,180 Infants........................................ 760 Children 1 to 6................................ 2,052 Females 13 years and older..................... 3,640 Males 13 years and older....................... 3,219
4. Non-threshold effects--Carcinogenicity. Using the Guidelines for Carcinogen
Risk Assessment, FMC believes sulfentrazone to be in 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 should not be necessary.
5. Aggregate exposure. For purposes of assessing the potential dietary exposure,
FMC has estimated aggregate exposure based on the Theoretical Maximum Residue
Contribution (TMRC) from the tolerances for sulfentrazone on soybeans at
0.05 ppm and rotational crop tolerances in cereal grains from 0.1 to 0.5
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.)
Dietary exposure to residues of sulfentrazone in or on food will be limited
to residues on soybeans and cereal grains. Forage and straw from cereal
grains are fed to animals; thus exposure of humans to residues might result
if such residues carry through to meat, milk, poultry or eggs. However,
FMC believes that there is no reasonable expectation that measurable residues
of sulfentrazone will occur in meat, milk, poultry or eggs from this use.
There are no other established U.S. tolerances for sulfentrazone, and there
are no registered uses for sulfentrazone on food or feed crops in the U.S.
In conducting this exposure assessment, very conservative assumptions--100%
of soybeans and cereal grains will contain sulfentrazone residues and those
residues would be at the level of the tolerances have been used which results
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 nonoccupational sources.
While the majority of field studies with sulfentrazone indicate that movement
into groundwater will not occur, a single study in very vulnerable
[[Page 57422]]
soil has shown that a small percentage of material could reach shallow
groundwater under extreme conditions. Based on this worst case situation,
the maximum exposure to residues of sulfentrazone in drinking water resulting
from product use at extremely vulnerable sites would be less than 50 ppb.
There is no established Maximum Contaminant Level(MCL) for residues of sulfentrazone
in drinking water under the Safe Drinking Water Act. However, a reasonable
estimate of the sulfentrazone MCL using the appropriate methodology would
be 350 ppb. The dietary contribution from these residues is included in
the safety determination for both the U.S. population and infants (shown
below). Non-occupational exposure for sulfentrazone has not been estimated
since the current registration for sulfentrazone is limited to commercial
soybean production. The potential for nonoccupational exposure to the general
population is, thus, insignificant. 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 sulfentrazone would be cumulative
with those of any other chemical compounds. 6. Determination of safety for
U.S. population-- Reference Dose. Using the conservative exposure assumptions
described above, based on the completeness and reliability of the toxicity
data, the aggregate exposure to sulfentrazone will utilize 4.5 percent of
the RfD for the U.S. population. EPA generally has no concern for exposures
below 100 percent of the Reference Dose (RFD). Therefore, based on the completeness
and reliability of the toxicity data and the conservative exposure assessment,
FMC, concludes that there is a reasonable certainty that no harm will result
from aggregate exposure to residues of sulfentrazone, including all anticipated
dietary exposure and all other non-occupational exposures.
7. Determination of safety for infants and children. Developmental toxicity
was observed in developmental toxicity studies using rats and rabbits. The
NOELs for developmental effect were established at 10 mg/ kg/day in the
rat study and 100 mg/kg/day in the rabbit study. The developmental effect
observed in these studies is believed to be a secondary effect resulting
from decreased oxygen transport to the fetus.
Reference Dose. Using the conservative exposure assumptions described above,
FMC has concluded that the percent of the RfD utilized by aggregate exposure
to residues of sulfentrazone ranges from 4.3 percent for children 1 to 6
years old, up to 13.5 percent for nonnursing infants. EPA generally has
no concern for exposure below 100 percent of the Reference Dose. Therefore,
based on the completeness and reliability of the toxicity data and the conservative
exposure assessment, FMC concludes that there is a reasonable certainty
that no harm will result to infants and children from aggregate exposure
to the residues of sulfentrazone, including all anticipated dietary exposure
and all other non-occupational exposures. 8. Estrogenic effects. No specific
tests have been conducted with sulfentrazone to determine whether the pesticide
may have an effect in humans that is similar to an effect produced by a
naturally occurring estrogen or other endocrine effects.
9. Chemical residue. The qualitative nature of the residues in plants and
animals is adequately understood for the purposes of registration. Residues
of sulfentrazone do not concentrate in the processed commodities. There
are no Codex maximum residue levels established for residues of sulfentrazone
on soybeans. FMC has submitted a practical analytical method for detecting
and measuring levels of sulfentrazone 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. EPA will information on this method to the Food and
Drug Administration. The method is available to anyone who is interested
in pesticide residue enforcement from the Field operations Division, Office
of Pesticide Programs. Forty separate residue trials have been conducted
with sulfentrazone on soybeans. Analysis of these trials shows that the
maximum total combined residue for sulfentrazone and its major metabolite
will be below 0.05 ppm. Virtually no detectable residues of sulfentrazone
were found in soybean meal, soapstock and oil treated at an exaggerated
rate. Because of the very low level of these residues, no food additive
tolerances are being proposed for these processed commodities.
Tolerances have been requested for residues of sulfentrazone and its major
metabolite on soybean seed at the low level of 0.05 ppm. In addition, tolerances
for residues of sulfentrazone and its major metabolites have been requested
to cover inadvertent residues found in rotational crops of the cereal grain
crop grouping (excluding sweet corn). For these rotational crop tolerances,
the requested levels are as follows: 0.1 ppm in or on grain; 0.2 ppm in
or on hay; 0.6 ppm in or on straw; 0.2 ppm in or on forage; 0.1 ppm in or
on stover and 0.2 ppm in or on bran.
The proposed tolerance levels are adequate to cover residues likely to be
present from the proposed use of sulfentrazone. Therefore, no special processing
to reduce the residues will be necessary. 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 goat and
poultry metabolism studies, as well as the soybean metabolism and crop rotation
studies. Calculated transfer factors are extremely low and maximum expected
residues in meat, milk, poultry and eggs would be in the part per trillion
range. Since the level of detection of the available methods would be higher
than the maximum expected level in each of the matrixes, no detectable residues
would be found.
10. Environmental fate. Laboratory studies indicate that sulfentrazone has
the potential to persist in soil and be mobile. However, the results of
field dissipation studies run in the three largest soybean producing states
(Iowa, Illinois, Arkansas) indicate that downward movement of sulfentrazone
is limited, with no quantifiable residues being found below 18. In a single
field study conducted under highly vulnerable conditions (very high sand
content and low organic matter), small amounts of sulfentrazone were detected
in shallow groundwater when sulfentrazone was applied at exaggerated rates.
The site for this study received excessive record rainfall early during
the study which contributed to the movement observed. Sulfentrazone has
been found to be stable to chemical hydrolysis in the pH range of environmental
concern. However, the compound is subject to rapid extensive degradation
in water in the presence of natural sunlight. Under these conditions, sulfentrazone
residues rapidly break down, with more than 50% of the residue disappearing
in 1 hour at environmental pH. Under aerobic conditions in soil, the major
metabolic pathway for sulfentrazone is oxidation of the methyl group on
the triazolinone ring. A minor metabolic pathway under aerobic conditions
is the cleavage of the sulfonamide group on sulfentrazone. Sulfentrazone
residues do not bioaccumulate in fish.
II. Administrative Matters
Interested persons are invited to submit comments on this notice of filing. Comments must bear a notation indicating the document control number, [PF-670]. All written comments filed in response to this
[[Page 57423]]
petition will be available, in the Public Response and Program Resources Branch, at the address given above from 8 a.m. to 4 p.m., Monday through Friday, except legal holidays. A record has been established for this notice of filing under docket number [PF-670] 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 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The public record is located in Room 1132 of the Public Response and Program resources Branch, Field Operations Division (7506C), Office of Pesticide Programs, Environmental Protection Agency, Crystal Mall #2, 1921 Jefferson Davis highway, Arlington, VA. Electronic comments can be sent directly to EPA at:
opp=Docket@epamail.epa.gov
Electronic comments must be submitted as ASCII file avoiding the use of
special characters and any form of encryption. The official record for this
notice of filing, as well as the public version, as described above will
be kept in paper form. Accordingly, EPA will transfer all comments received
electronically into printed, paper form as they are received and will place
the paper copies in the official record which will also include all comments
submitted directly in writing. The official rulemaking record is the paper
record maintained at the address in ``ADDRESSES'' at the beginning of this
document.
List of Subjects
Environmental Protection, Administrative practice and procedure, Agricultural commodities, Pesticides and pests, Reporting and recordkeeping requirements.
Dated: October 21, 1996.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 96-28422 Filed 11-5-96; 8:45 am] BILLING CODE 6560-50-F