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Cyfluthrin. March 14, 1997. Submission by Bayer Corporation for Pesticide Tolerances. Federal Register.
http://www.epa.gov/docs/fedrgstr/EPA-PEST/1997/March/Day-14/p6516.htm
[Federal Register: March 14, 1997 (Volume 62, Number 50)]
[Notices]
[Page 12182-12185]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14mr97-66]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-717; FRL-5590-2]
Bayer Corporation; Pesticide Tolerance Petition Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
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SUMMARY: This notice announces the filing of a pesticide petition
proposing regulations establishing tolerances for residues of the
pyrethroid cyfluthrin in or on the raw agricultural commodities (RACs)
group citrus, fruits and to establish a maximum residue limit for
cyfluthrin on citrus oil and dried pulp. This notice includes a summary
of the petition that was prepared by Bayer Corporation.
DATES: Comments, identified by the docket control number [PF-717], must
be received on or before April 14, 1997.
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 be 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 5.1 file format or in ASCII file
format. All comments and data in electronic form must be identified by
docket control number [PF-717]. Electronic comments on this notice may
be filed online at many Federal Depository Libraries. Additional
information on electronic submissions can be found below 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 8:30 a.m. to 4 p.m., Monday through Friday,
excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: By mail: George T. LaRocca, Product
Manager (PM) 13, Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW., Washington,
DC 20460. Office location, telephone number, and e-mail address: Rm.
200, CM #2, 1921 Jefferson Davis Highway, Arlington, VA 22202. (703)
305-6100; larocca.george@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA has received pesticide petitions (PP)
4F4313 and 4H5687 from Bayer Corporation, 8400 Hawthorn Road, Kansas
City, MO 64120. The petition proposes, pursuant to section 408(d) of
the Federal Food Drug and Cosmetic Act, 21 U.S.C. section 346a, to
amend 40 CFR 180.436 to establish tolerances for residues of the
insecticide cyfluthrin, [cyano[4-fluoro-3-phenoxyphenyl]-methyl-3-[2,2-
dicloroethenyl]-2,2-dimethylcyclopropanecarboxylate] in or on the raw
agricultural commodities group citrus, fruits at 0.2 part per million
(ppm) and the processed commodities citrus, oil and citrus, dried pulp
at 0.3 part per million (ppm). The proposed analytical method is gas
chromatography equipped with electron capture detector.
As required by section 408(d) of the FFDCA, as recently amended by
the Food Quality Protection Act, Bayer Corporation 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 receipt of the
petition. The summary represents the views of Bayer Corporation; 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.
I. Petition Summary
A. Residue Chemistry
1. Use pattern. Baythroid 2 will be used on citrus only in
California and Arizona, to control citrus thrips. A dosage of 6.4 fluid
ounces of Baythroid 2 (0.1 lb active ingredient per acre) will be
applied by ground equipment only, in sufficient water for complete
coverage of foliage in dilute or concentrate sprays, but not less than
25 gallons per acre. A single application may be made per season.
2. Plant metabolism. The metabolism of cyfluthrin in plants is
adequately understood. Studies have been conducted to delineate the
metabolism of radiolabeled cyfluthrin in various crops all showing
similar results. The residue of concern is cyfluthrin.
3. Analytical methodology. Adequate analytical methodology (Gas
liquid chromatography with an electron capture detector) is available
for enforcement purposes.
The established tolerances for residues of cyfluthrin in/on eggs,
milks, fat, meat and meat by-products of cattle, goats, hogs, horses,
sheep and poultry are adequate to cover secondary residues resulting
from the proposed use as delineated in 40 CFR 180.6(a)(2).
4. Magnitude of the residue. On December 20, 1993, Bayer Corp.
filed a petition (PP 4F4313) for a tolerance for residues of cyfluthrin
on the raw agricultural commodity, citrus and proposed food/feed
additive regulation (4H5687) for citrus oil, citrus dried pulp, and
citrus molasses under section 409 of FFDCA. A request was filed May 2,
1996, to withdraw the feed additive petition for citrus molasses,
submitted in response to EPA's determination that citrus molasses is no
longer considered a significant feed item. See EPA's final 860 Series
Residue Chemistry Guidelines (860.1000) published as public drafts on
August 25, 1995 (60 FR 44343) (formerly Table II of Subdivision O,
Residue Chemistry, of the Pesticide Assessment Guidelines).
The food/feed additive petition for citrus oil and citrus dried
pulp has been revised to propose these tolerances at 0.3 ppm under
section 408 instead section 409 in accordance the Food Quality
Protection Act.
The proposed section 408 tolerance for cyfluthrin on citrus is 0.2
ppm. The highest average residue found in crop field trials for
cyfluthrin on citrus fruits was 0.06 ppm. A processing study showed
that in producing citrus oil and dried pulp residues concentrated 530
(a concentration factor of 5.3 x ). Thus with this information it is
likely that cyfluthrin residues of 0.32 ppm (0.06 x 5.3) could occur
in citrus oil and dried pulp.
B. Toxicological Profile
The data base for cyfluthrin is essentially complete. Data lacking
but desirable are an acute neurotoxicity study in rats and a 90-day
neurotoxicity study in rats. Although these data are lacking, Bayer
Corp. believes there is sufficient toxicity data to support the
proposed tolerance and these missing data will not significantly change
the risk assessment. In a letter dated November 2, 1995, Bayer Corp.
has committed to submit the acute neurotoxicity study by December 1996
[[Page 12183]]
and the 90-day neurotoxicity study by May 1997.
The toxicology data cited in support of the tolerance include:
1. Chronic effects. A 12-month chronic feeding study in dogs with a
no-observed effect level (NOEL) of 4 mg/kg/day. The lowest effect level
(LEL) for this study is established at 16 mg/kg/day, based on slight
ataxia, increased vomiting, diarrhea and decreased body weight.
A 24-month chronic feeding/carcinogenicity study in rats with a
NOEL of 2.5 mg/kg/day and LEL of 6.2 mg/kg/day, based on decreased body
weights in males, decreased food consumption in males, and inflammatory
foci in the kidneys in females.
2. Acute toxicity. For the purposes of assessing acute dietary
risk, the Agency has used an oral developmental toxicity study in
rabbits with a maternal NOEL of 20 mg/kg/day and a maternal LEL of 60
mg/kg/day, based on decreased body weight gain and decreased food
consumption during the dosing period. A fetal NOEL of 20 mg/kg/day and
a fetal LEL of 60 mg/kg/day were also observed in this study. The LEL
was based on increased resorptions and increased postimplantation loss.
3. Carcinogenicity. A 24-month carcinogenicity study in mice was
conducted. There were no carcinogenic effects observed under the
conditions of the study.
A 24-month chronic feeding/carcinogenicity study in rats was
conducted. There were no carcinogenic effects observed under the
conditions of the study.
Mutagenicity tests were conducted, including several gene mutation
assays (reverse mutation and recombination assays in bacteria and a
Chinese hamster ovary(CHO)/HGPRT assay); a structural chromosome
aberration assay (CHO/sister chromatid exchange assay); and an
unscheduled DNA synthesis assay in rat hepatocytes. All tests were
negative for genotoxicity.
4. Other. A metabolism study in rats showed that cyfluthrin is
rapidly absorbed and excreted, mostly as conjugated metabolites in the
urine, within 48 hours. An enterohepatic circulation was observed.
C. Aggregate Exposure
A chronic dietary exposure/risk assessment was performed for
cyfluthrin using a Reference Dose (RfD) of 0.025 mg/kg bwt/day, based
on a NOEL of 50 ppm (2.5 mg/kg bwt/day) and an uncertainty factor of
100. The NOEL was determined in a 2-year rat feeding study. The
endpoint effects of concern were decreased body weights in males and
inflammation of the kidneys in females at the LEL of 6.2 mg/kg/day. For
purposes of this dietary exposure/risk assessment tolerance level
residues were used and percent crop treated assumption made for some of
the commodities. The current estimated dietary exposure for the overall
U.S. population resulting from established tolerances 0.009420 mg/kg/
bwt/day or 37.6 percent of the RfD. The current estimated dietary
exposure for the subgroup population exposed to the highest risk, non-
nursing infants less than 1 year old, 0.025266 mg/kg bwt/day or 101
percent of the RfD. Although the estimate of dietary exposure for the
subgroup, non-nursing infants less than 1 year old, is slightly higher
than the Agency's level of concern, i.e., greater than 100 percent of
the RfD, Bayer Corp. believes that actual exposure and risk would be
lower. The basis for this is that the risk reflects a higher than
actual dietary exposure because it assumes that 100 percent of most
commodities for which cyfluthrin tolerances exist have cyfluthrin
residues and that all will bear residue levels as high as the
tolerances. In reality, all these commodities will not have residues of
this pesticide and actual levels will be lower than tolerance levels.
To assess the dietary exposure from the establishment of the proposed
citrus tolerances, the incremental increase in dietary exposure was
taken from the dietary exposure analysis conducted by the Agency. These
estimates are based on the assumption that 100 percent of the citrus
crop in the U.S. would be treated with cyfluthrin. In reality, this use
of cyfluthrin will be limited to California and Arizona only for the
control of citrus thrips. For the prior six years, cyfluthrin has been
utilized in the California's Central Valley under the provisions of a
FIFRA section 18 Emergency Exemption. In 1995, approximately 77,000 out
of 170,000 acres (46 percent) of the citrus grown in Central Valley was
treated with cyfluthrin. Assuming that a similar proportion of acreage,
that is 46 percent, would be treated throughout California and Arizona,
the total estimated acreage treated with cyfluthrin would be 94,000
acres. This represents only 9.4 percent of the 1,026,000 fruit bearing
acres of citrus grown in the U.S. Therefore, a 10 percent treated crop
adjustment to the dietary exposure can be considered appropriate.
Adding this incremental exposure to the current estimated dietary
exposure results in a total dietary exposure for the U.S. population of
0.0094934 mg/kg bwt/day representing 38 percent of RfD. The highest
exposure group, non-nursing infants will increase only very slightly,
to 0.253653 mg/kg bwt/day representing 101.4 percent of the RfD. As
described above, although this still slightly exceeds the RfD, actual
exposure is expected to be much less.
Generally speaking, EPA has no cause for concern if the total
dietary exposure from residues for uses for which there are published
and proposed tolerances is less than the RfD. Therefore Bayer concludes
that the chronic dietary risk of cyfluthrin, as estimated by the
dietary risk assessment, does not appear to be of concern.
Other potential sources of exposure to residues of pesticides are
residues in drinking water and exposure from non-occupational sources.
Based on available studies used in previous EPA assessments, Bayer
Corp. does not anticipate exposures to cyfluthrin in drinking water.
Non-occupational exposure to cyfluthrin may occur as a result of
inhalation or contact from indoor residential, indoor commercial, and
outdoor residential uses. The Agency does not currently have reliable
data to determine aggregate exposures from these sources. However,
determinations of worst case exposure from inhalation in indoor
settings (continuous exposure at saturation vapor concentration) should
indicate that adequate margins of safety exist even under these
conditions. Since this evaluation greatly overestimates exposure, the
contribution to aggregate exposure from inhalation in normal uses would
be expected to be negligible. Estimations of outdoor residential
exposure have been required for cyfluthrin in a data call-in issued in
1995. These data are being generated by the Outdoor Residential
Exposure Task Force (ORETF). However, available data show that the
acute dermal toxicity of cyfluthrin is very low, with the LD50
being greater than 5,000 mg/kg, the highest dose tested. Sub-acute (21-
day) dermal toxicity data showed only localized (skin) effects at
higher level exposures (1,000 mg/kg/day and 340 mg/kg/day). Other than
skin effects at these high exposure levels, no effects were observed at
any exposure levels, the highest level tested being 1,000 mg/kg/day.
The use rate for cyfluthrin on residential turf is 1 g (1,000 mg)
active ingredient per 1000 square feet which would indicate that
potential exposures would be well below levels tested. In addition, the
localized skin effects seen at the prolonged higher exposures in animal
tests have not been reported for non-occupational exposures to
cyfluthrin in currently accepted uses,
[[Page 12184]]
indicating that exposures are below the threshold of any observable
effects. Indoor uses are limited to areas with little or no contact, so
exposures would be expected to be even less. Thus, the dermal route of
exposure does not appear to be significant and the contribution to
aggregate exposure from dermal contact would be expected to be
negligible.
In consideration of potential cumulative effects of cyfluthrin and
other substances that have a common mechanism of toxicity, there are
currently no available data or other reliable information indicating
that any toxic effects produced by cyfluthrin would be cumulative with
those of other chemical compounds; thus only the potential risks of
cyfluthrin have been considered in this assessment of its aggregate
exposure.
D. Safety Determinations
1. U.S. population in general. Using the conservative exposure
assumptions described above and based on the completeness and
reliability of the toxicity data it can be concluded that total
aggregate exposure to cyfluthrin from all current uses as well as the
proposed tolerance and maximum residue levels for the use of cyfluthrin
on citrus will utilize little more than 38 percent of the RfD for the
U.S. population. EPA generally has no concerns for exposures below 100
percent of the RfD, because the RfD represents the level at or below
which daily aggregate exposure over a lifetime will not pose
appreciable risks to human health. Thus, it can be concluded that there
is a reasonable certainty that no harm will result from aggregate
exposure to cyfluthrin residues.
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of cyfluthrin, the data
from developmental studies in both rat and rabbit and a 2-generation
reproduction study in the rat can be considered. The developmental
toxicity studies evaluate any potential adverse effects on the
developing animal resulting from pesticide exposure of the mother
during prenatal development . The reproduction study evaluates any
effects from exposure to the pesticide on the reproductive capability
of mating animals through two generations, as well as any observed
systemic toxicity.
The toxicology data cited in support of the tolerance include: An
oral developmental toxicity study in rats with a maternal and fetal
NOEL of 10 mg/kg/day (highest dose tested). An oral developmental
toxicity study in rabbits with a maternal NOEL of 20 mg/kg/day and a
maternal LEL of 60 mg/kg/day, based on decreased body weight gain and
decreased food consumption during the dosing period. A fetal NOEL of 20
mg/kg/day and a fetal LEL of 60 mg/kg/day were also observed in this
study. The LEL was based on increased resorptions and increased
postimplantation loss.
A developmental toxicity study in rats by the inhalation route of
administration with a maternal NOEL of 0.0011 mg/l and a LEL of 0.0047
mg/l, based on reduced mobility, dyspnea, piloerection, ungroomed coats
and eye irritation. The fetal NOEL is 0.00059 mg/l and the fetal LEL is
0.0011 mg/l, based on sternal anomalies and increased incidence of
runts. A second developmental toxicity study in rats by the inhalation
route of administration has been submitted to the Agency and is
currently under review.
A three-generation reproduction study in rats with a systemic NOEL
of 2.5 mg/kg/day and a systemic LEL of 7.5 mg/kg/day due to decreased
parent and pup body weights. The reproductive NOEL and LEL are 7.5 mg/
kg/day and 22.5 mg/kg/day respectively.
The Agency used the rabbit developmental toxicity study with a
maternal NOEL of 20 mg/kg/day to assess acute dietary exposure and
determine a margin of exposure (MOE) for the overall U.S. population
and certain subgroups. Since this toxicological endpoint pertains to
developmental toxicity the population group of concern for this
analysis was women aged 13 and above, the subgroup which most closely
approximates women of child-bearing age. The MOE is calculated as the
ration of the NOEL to the exposure. For this analysis the Agency
calculated the MOE to be over 600. Generally, MOE's greater than 100
for data derived from animal studies are regarded as showing no
appreciable risk.
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 effects and the completeness of the
toxicity database. Based on current toxicological data requirements,
the toxicology database for cyfluthrin relative to pre- and post-natal
effects is complete. The no-effect-levels observed in the developmental
and reproduction study are equivalent or higher than the NOEL from the
2-year rat feeding study, used with a 100 fold uncertainty factor to
establish the reference dose.
Therefore, an additional uncertainty factor is not warranted and
that the RfD at 0.025 mg/kg/day is appropriate for assessing aggregate
risk to infants and children.
Using the conservative exposure assumptions described above, EPA
has previously concluded that the residues from use of cyfluthrin on
citrus will contribute the highest incremental increase to the
aggregate exposure to the population subgroup children 1 to 6 years
old, accounting for 3.9 percent of the RfD and giving a total dietary
exposure from all uses of 95.9 percent of the RfD for this subgroup.
However, this assessment was based on an assumption of 100 percent crop
treated. When adjusted for a 10 percent crop treatment (as described in
section B. above) the incremental exposure is negligible, increasing
form the current 0.022985 mg/kg bwt /day (91.9 percent of the RfD) to
0.231522 mg /kg bwt/day or 92.6 percent of the RfD. For nursing infants
current exposure is 0.005692 mg/kg bwt/day or 22.8 percent of the RfD.
The use on citrus would increase exposure to 0.0057377 mg/kg bwt/day
representing 22.9 percent of the RfD. For children 7 to 12, current
exposure is 0.015237 mg/kg bwt/ day, 60.9 percent of the RfD. The use
on citrus would increase this to 0.153416 mg/kg bwt /day, or 61.4
percent of the RfD. For non-nursing infants, the current is exposure is
calculated to be 0.025267 mg/kg bwt /day, 101 percent of the RfD. The
use on citrus would increase this slightly to 0.0253653 or 101.4
percent. Both the current and the resulting calculated exposure from
adding the estimated exposure from citrus exposure are slightly higher
than the Agency's level of concern. However, the Agency has previously
assessed this risk in the evaluation of PP 2F4137 and believed the
actual exposure and risk would be much lower. The basis for this was
the fact that this calculated exposure assumes, with the exception of
citrus, that 100 percent of the commodities for which cyfluthrin
tolerance exists have residues and that the residues all bear residues
as high as the tolerance levels. In reality, it is known that not all
commodities will have cyfluthrin residues and actual levels will be
lower than the tolerance values. In addition, the food commodity that
contributes most to this slight exceedence is milk, at 88.2 percent of
the RfD; 71.2 percent from milk fat and 17 percent from whole milk and
milk sugars. However, metabolism data indicate that essentially all of
the cyfluthrin will concentrate in milk fat and there would be
negligible amounts in other components. Thus the 17 percent
contribution from non-milk fat portions of milk is an overestimation of
actual
[[Page 12185]]
exposure, which would be below the RfD.
Generally, EPA has no cause for concern if the total aggregate
exposure is less than the RfD, therefore it may be concluded that there
is a reasonable certainty of no harm will result to infants and
children.
E. Conclusions
The available data indicate that there is reasonable certainty of
no harm from the incremental exposure resulting from the potential
residues of cyfluthrin from the use of Baythroid 2, EPA Reg. No. 3125-
351, on citrus. Thus in accordance with the provisions of the FFDCA as
amended August 3, 1996, regulations to establish the tolerance and
maximum residue levels to support this use can be effected.
F. International Tolerances
There are no Codex maximum residue levels (MRLs) established for
residues ofcyfluthrin on citrus fruits or any resulting processed
products.
II. Public Record
Interested persons are invited to submit comments on this notice of
filing. Comments must bear a notation indicating the docket control
number, [PF-717]. All written comments filed in response to this
petition will be available in the Public Response and Program Resources
Branch, at the address given above from 8:30 a.m. to 4 p.m., Monday
through Friday, except legal holidays.
A record has been established for this notice under docket control
number [PF-717] 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 public
record is located in Rm. 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, 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 record is the paper record maintained at the
address in ``ADDRESSES'' at the beginning of this document.
Authority: 21 U.S.C. 346a.
List of Subjects
Environmental Protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: March 7, 1997.
Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 97-6516 Filed 3-13-97; 8:45 am]
BILLING CODE 6560-50-F