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Bifenthrin - Pesticide Petition Filing 5/99

[Federal Register: May 19, 1999 (Volume 64, Number 96)]
[Notices]
[Page 27262-27266]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19my99-58]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-873; FRL-6079-8]
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-873, must
be received on or before June 18, 1999.

ADDRESSES: By mail submit written comments to: Information and Records
Integrity Branch, Public Information and Services Divison (7502C),
Office of Pesticides Programs, Environmental Protection Agency, 401 M
St., SW., Washington, DC 20460. In person bring comments to: Rm. 119,
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. 119 at the
address given above, from 8:30 a.m. to 4 p.m., Monday through Friday,
excluding legal holidays.

FOR FURTHER INFORMATION CONTACT:.Sidney Jackson, Registration Support
Branch, 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. 272, Crystal
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA 22202, (703) 305-
7610; e-mail:jackson. sidney@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 chemical 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
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

[[Page 27263]]

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-873] (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 5.1/6.1 file format or
ASCII file format. All comments and data in electronic form must be
identified by the docket control number (PF-873) 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, 1999.

Peter Caulkins,

Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    The petitioner summary of the pesticide petitions is printed below
as required by section 408(d)(3) of the FFDCA. The summary of the
petitions was prepared by the petitioner and represents the views of
the petitioner. EPA is publishing the petitions 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.

1. Interregional Research Project No. 4

 PP 6E4629, 6E4760, 8E4993, 8E5009, 9E5084, 9E5069, and 9E5064

    EPA has received pesticide petitions (6E4629, 6E4760, 8E4993,
8E5009, 9E5084, 9E5069, and 9E5064) from Interregional Research Project
No. 4 (IR-4), New Jersey Agricultural Experiment Station, P. O. Box
231, Rutgers University, New Brunswick, NJ 08903 and FMC Corporation,
Agricultural Group, 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 tolerances for
residues of the insecticide bifenthrin, 2-methyl-(1,1'-biphenyl)-3-yl
methyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2 dimethylcyclopropane
carboxylate in or on the raw agricultural commodities (RAC):

    1. PP 6E4629 proposes the establishment of a tolerance for
artichoke at 1 part per million (ppm).

    2. PP 6E4760 proposes the establishment of a tolerance for crop
group 9 cucurbit vegetables at 0.4 ppm.

    3. PP 8E4993 proposes the establishment of a tolerance for crop
subgroup 6B edible-podded legume vegetables at 0.2 ppm.

    4. PP 8E5009 proposes the establishment of a tolerance for eggplant
at 0.05 ppm.

    5. PP 9E5084 proposes the establishment of a tolerance for rapeseed
including, canola and crambe seed, at 0.05 ppm.

    6. PP 9E5069 proposes the establishment of a tolerance for crop
subgroup 5A Head and Stem Brassica, excluding cabbage, at 0.6 ppm and
cabbage at 4.0 ppm.

    7. PP 9E5064 proposes the establishment of a tolerance for crop
subgroup 6B, succulent shelled peas and beans at 0.5 ppm.

2. FMC Corporation

 PP 8F5014

    EPA has received a pesticide petition (8F5014) from FMC
Corporation, Agricultural Group, 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
tolerance for residues of the insecticide bifenthrin in or on the raw
agricultural commodity: sweet corn at 0.05 ppm and proposes to amend
the existing tolerance for corn forage from 2.0 to 3.0 ppm.

    EPA has determined that the petitions contain 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
petitions. Additional data may be needed before EPA rules on the
petitions.

A. Residue Chemistry

    1. Plant metabolism. The metabolism of bifenthrin in plants is
adequately understood. Studies have been conducted to delineate the
metabolism of radiolabelled bifenthrin in various crops all showing
similar results. The residue of concern is the parent compound only.

    2. Analytical method. The practical analytical method for detecting
and measuring levels of bifenthrin 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 Gas Chromatography with Electron Capture
Detection (GC/ECD) analytical method P-2132M.

    3. Magnitude of residues. Field bifenthrin residue trials for each
commodity, unless otherwise noted, were conducted according to approved
protocol that include 5 applications of the active ingredient (a.i.) at
a rate of 0.1 pounds (lbs.) a.i./ acre(A).

    Field residue trials have been conducted at the maximum label rate
for lima bean and succulent shelled peas. Results from these trials
demonstrate that the proposed bifenthrin tolerance of 0.05 ppm for
subgroup 6B succulent shelled peas and beans will not be exceeded when
the product is applied following the proposed use directions.

    Field residue trials meeting EPA study requirements have been
conducted at the maximum label rate for the crop canola. Results from
these trials demonstrate that the proposed bifenthrin tolerance of 0.05
ppm for rapeseed (including canola and crambe) will not be exceeded
when the product is applied following the proposed use directions.

    Residues of bifenthrin in or on artichoke were evaluated in two
field trials where artichokes were treated with bifenthrin at the rates
of 0.1 lb a.i./A or 0.2 lb a.i./A. Samples were taken 5 days after the
last treatment. Artichokes treated at the rate of 0.1 lb a.i./A had
residues as high as 0.67 ppm. Artichokes treated at the rate of 0.2 lb
a.i./A had residues as high as 0.62 ppm.

    Residue levels of bifenthrin in eggplant were evaluated in field
trails after two treatments at a rate of 0.1 lbs. a.i./A and samples
taken 7 days after the last application. No detectable residues

[[Page 27264]]

above the test method's limit of quantitation (L0Q) (0.05 ppm) were
found in any of the test samples.

    Field residue trials conducted for the cucurbit vegetable group
included a total of three foliar applications of bifenthrin at 0.1 lb
a.i./A to cucumber, cantaloupe and summer squash. The first foliar
application was applied prebloom; the second application was applied
post bloom; the third application was made post bloom 7 to 10 days
after the second application, except in one instance. In some trials,
fruit were harvested 0, 3 and 7 or 8 days after the last application.
In all cases, the maximum residue found did not exceed the proposed
tolerance of 0.4 ppm.

    For the head and stem brassica crop subgroup (5A), IR-4 proposed
that EPA establish a tolerance for bifenthrin on commodities, excluding
cabbage, at 0.6 ppm, and that a separate tolerance for cabbage be
established at 4.0 ppm. Samples were collected 6-8 days after the last
application for the analysis of residues. Residues up to 0.56 ppm
bifenthrin were found in broccoli and up to 0.19 ppm were found in
cauliflower samples. Treated cabbage sampled showed residues as high as
3.09 ppm in heads with wrapper leaves. The tolerance proposal for
bifenthrin on cabbage is based on residue data for cabbage with wrapper
leaves.

    Field residue trials were conducted at the maximum label rate for
the crop subgroup edible-podded legume vegetables. Results from these
trails demonstrate that the proposed bifenthrin tolerance of 0.2 ppm
(crop subgroup edible-podded legume vegetables) and 0.5 ppm (crop
subgroup succulent shelled pea) will not be exceeded when the product
is applied following the proposed use directions.

B. Toxicological Profile

    1. Acute toxicity. For the purposes of assessing acute dietary
risk, FMC has used the maternal no-observed adverse effect level
(NOAEL) of 1.0 milligrams/kilogram/day (mg/kg/day) from the oral
developmental toxicity study in rats. The maternal lowest-observed
adverse effect level (LOAEL) of this study of 2.0 mg/kg/day was based
on tremors from day 7-17 of dosing. This acute dietary endpoint is used
to determine acute dietary risks to all population subgroups.

    2. Genotoxicity. The following genotoxicity tests were conducted on
bifenthrin and all yielded negative results including: gene mutation in
Salmonella (Ames); chromosomal aberrations in Chinese hamster ovary and
rat bone marrow cells; hypoxanthine guanine phophoribosyl transferase
(HGPRT) locus mutation in mouse lymphoma cells; and unscheduled DNA
synthesis in rat hepatocytes.

    3. Reproductive and developmental toxicity--i. In the rat
reproduction study, parental toxicity occurred (decreased bwt) at 5 mg/
kg/day with a NOAEL of 3 mg/kg/day. There were no developmental (pup)
or reproductive effects up to 5.0 mg/kg/day highest dose tested (HDT).
See discussion of developmental toxicity studies in section E.2 of this
unit.

    ii. Postnatal sensitivity. Based on the absence of pup toxicity up
to dose levels which produced toxicity in the parental animals, there
is no evidence of special postnatal sensitivity to infants and children
in the rat reproduction study.

    4. Subchronic toxicity The maternal NOAEL of 1.0 mg/kg/day from the
oral developmental toxicity study in rats is also used for short- and
intermediate-term margin of exposure (MOE) calculations (as well as
acute, discussed in (1) above). The maternal LOAEL of this study of 2.0
mg/kg/day was based on tremors from day 7-17 of dosing.

    5. Chronic toxicity--i. The reference dose (RfD) has been
established at 0.015 mg/kg/day. This RfD is based on a 1-year oral
feeding study in dogs with a NOAEL of 1.5 mg/kg/day, based on
intermittent tremors observed at the LOAEL of 3.0 mg/kg/day; an
uncertainty factor of 100 is used.

    ii. Bifenthrin is classified as a Group C chemical (possible human
carcinogen) based upon urinary bladder tumors in mice; assignment of a
Q* has not been recommended.

    6. Animal metabolism. The metabolism of bifenthrin in animals is
adequately understood. Metabolism studies in rats with single doses
demonstrated that about 90% of the parent compound and its hydroxylated
metabolites are excreted.

    7. Metabolite toxicology. The Agency has previously determined that
the metabolites of bifenthrin are not of toxicological concern and need
not be included in the tolerance expression.

    8. Endocrine disruption. To date, no special studies investigating
potential estrogenic or other endocrine effects of bifenthrin have been
conducted. However, no evidence of such effects were reported in the
standard battery of required toxicology studies which have been
completed and found acceptable. Based on these studies, FMC Corporation
concludes that there is no evidence to suggest that bifenthrin has an
adverse effect on the endocrine system.

C. Aggregate Exposure

    1. Dietary exposure--i. Food. Tolerances have been established for
the residues of bifenthrin, in or on a variety of raw agricultural
commodities including: hops; strawberries; corn grain, forage, and
fodder; cottonseed; and livestock commodities of cattle, goats, hogs,
horses, sheep, poultry, eggs and milk. Pending tolerances for
artichokes, the crop group cucurbit vegetables, the crop subgroup
edible-podded legume vegetables and subgroup succulent shelled pea and
bean, eggplant, citrus, raspberries, sweet corn, canola, and the
subgroup head and stem brassica also exist. For the purposes of
assessing the potential dietary exposure for the existing and pending
tolerances, FMC has utilized available information on anticipated
residues, monitoring data and percent crop treated as follows:

    ii. Acute exposure and risk. Acute dietary exposure risk
assessments are performed for a food-use pesticide if a toxicological
study has indicated the possibility of an effect of concern occurring
as a result of a 1-day or single exposure. For the purposes of
assessing acute dietary risk for bifenthrin, the maternal NOAEL of 1.0
mg/kg/day from the oral developmental toxicity study in rats was used.
The maternal LOAEL of this study of 2.0 mg/kg/day was based on tremors
from day 7-17 of dosing. This acute dietary endpoint was used to
determine acute dietary risks to all population subgroups. Available
information on anticipated residues, monitoring data and percent crop
treated was incorporated into a Tier 3 analysis, using Monte Carlo
modeling for commodities that may be consumed in a single serving.
These assessments show that the MOEs are greater than the EPA standard
of 100 for all subpopulations. The 99.9th percentile of exposure for
the overall U.S. population was estimated to be 0.005278 mg/kg/day (MOE
of 189). The 99.9th percentile of exposure for all infants < 1-year old
was estimated to be 0.006255 mg/kg/day (MOE of 159). The 99.9th
percentile of exposure for nursing infants < 1-year old was estimated
to be 0.004280 mg/kg/day (MOE of 233). The 99.9th percentile of
exposure for non-nursing infants < 1-year old was estimated to be
0.005812 mg/kg/day (MOE of 172). The 99.9th percentile of exposure for
children 1 to 6 years old (the most highly exposed population subgroup)
was estimated to be 0.009578 mg/kg/day (MOE of 104). Therefore, FMC
concludes that the acute dietary risk of

[[Page 27265]]

bifenthrin, as estimated by the dietary risk assessment, does not
appear to be of concern.

    iii. Chronic exposure and risk. The acceptable RfD is 0.015 mg/kg/
day, based on a NOAEL of 1.5 mg/kg/day from the chronic dog study and
an uncertainty factor of 100. The endpoint effect of concern were
tremors in both sexes of dogs at the L0AEL of 3.0 mg/kg/day. A chronic
dietary exposure/risk assessment has been performed for bifenthrin
using the above RfD. Available information on anticipated residues,
monitoring data and percent crop treated was incorporated into the
analysis to estimate the Anticipated Residue Contribution (ARC). The
ARC is generally considered a more realistic estimate than an estimate
based on tolerance level residues. The ARC are estimated to be 0.000356
mg/kg bwt/day and utilize 2.4% of the RfD for the overall U. S.
population. The ARC for children 7-12 years old and children 1-6 years
old (subgroups most highly exposed) are estimated to be 0.000558 mg/kg
bwt/day and 0.001008 mg/kg bwt/day and utilizes 3.7% and 6.7% of the
RfD, respectively. Generally speaking, the 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 100% of the RfD.
Therefore, FMC concludes that the chronic dietary risk of bifenthrin,
as estimated by the dietary risk assessment, does not appear to be of
concern.

    iv. Drinking water. Laboratory and field data have demonstrated
that bifenthrin is immobile in soil and will not leach into ground
water. Other data show that bifenthrin is virtually insoluble in water
and extremely lipophilic. As a result, FMC concludes that residues
reaching surface waters from field runoff will quickly adsorb to
sediment particles and be partitioned from the water column. Further, a
screening evaluation of leaching potential of a typical pyrethroid was
conducted using EPA's Pesticide Root Zone Model (PRZM3). Based on this
screening assessment, the potential concentrations of a pyrethroid in
ground water at depths of 1 and 2 meters are essentially zero < 0.001
parts per billion (ppb). Surface water concentrations for pyrethroids
were estimated using PRZM3 and Exposure Analysis Modeling System
(EXAMS) using standard EPA cotton runoff and Mississippi pond
scenarios. The maximum concentration predicted in the simulated pond
was 0.052 ppb. Concentrations in actual drinking water would be much
lower than the levels predicted in the hypothetical, small, stagnant
farm pond model since drinking water derived from surface water would
normally be treated before consumption. Based on these analyses, the
contribution of water to the dietary risk estimate is negligible.
Therefore, FMC concludes that together these data indicate that
residues are not expected to occur in drinking water.

    v. Non-dietary exposure. Analyses were conducted which included an
evaluation of potential non-dietary (residential) applicator, post-
application and chronic dietary aggregate exposures associated with
bifenthrin products used for residential flea infestation control and
agricultural/commercial applications. The aggregate analysis
conservatively assumes that a person is concurrently exposed to the
same active ingredient via the use of consumer or professional flea
infestation control products and to chronic level residues in the diet.
In the case of potential non-dietary health risks, conservative point
estimates of non-dietary exposures, expressed as total systemic
absorbed dose (summed across inhalation and incidental ingestion
routes) for each relevant product use category (i.e., lawn care) and
receptor subpopulation (i.e., adults, children 1-6 years and infants <
1-year) are compared to the systemic absorbed dose NOAEL for bifenthrin
to provide estimates of the MOEs. Based on the toxicity endpoints
selected by EPA for bifenthrin, inhalation and incidental oral
ingestion absorbed doses were combined and compared to the relevant
systemic NOAEL for estimating MOEs.

    In the case of potential aggregate health risks, the above
mentioned conservative point estimates of inhalation and incidental
ingestion non-dietary exposure (expressed as systemic absorbed dose)
are combined with estimates (arithmetic mean values) of chronic average
dietary (oral) absorbed doses. These aggregate absorbed dose estimates
are also provided for adults, children 1-6 years and infants < 1-year.
The combined or aggregated absorbed dose estimates (summed across non-
dietary and chronic dietary) are then compared with the systemic
absorbed dose NOAEL to provide estimates of aggregate MOEs.

    The non-dietary and aggregate (non-dietary + chronic dietary) MOEs
for bifenthrin indicate a substantial degree of safety. The total non-
dietary (inhalation + incidental ingestion) MOEs for post-application
exposure for the lawn care product evaluated was estimated to be >
194,000 for adults, 52,400 for children 1-6 years old and 56,700 for
infants < 1-year. The aggregate MOE (inhalation + incidental oral +
chronic dietary, summed across all product use categories) was
estimated to be 2,664 for adults, 653 for children 1-6 years old and
1,042 for infants (< 1-year). It can be concluded that the potential
non-dietary and aggregate (non-dietary + chronic dietary) exposures for
bifenthrin are associated with substantial margins of safety.

D. Cumulative Effects

     In consideration of potential cumulative effects of bifenthrin and
other substances that may have a common mechanism of toxicity, FMC
Corporation concludes that there are currently no available data or
other reliable information indicating that any toxic effects produced
by bifenthrin would be cumulative with those of other chemical
compounds, thus only the potential risks of bifenthrin have been
considered in this assessment of its aggregate exposure. FMC intends to
submit information for EPA to consider concerning potential cumulative
effects of bifenthrin consistent with the schedule established by EPA
in the Federal Register of August 4, 1997 (62 FR 42020) (FRL-5734-6)
and other EPA publications pursuant to the Food Quality Protection Act.

E. Safety Determination

    1. U.S. population. The established RfD is 0.015 mg/kg/day, based
on a NOAEL of 1.5 mg/kg/day from the chronic dog study and an
uncertainty factor of 100. Available information on anticipated
residues, monitoring data and percent crop treated was incorporated
into an analysis to estimate the ARC for 26 population subgroups. The
ARC is generally considered a more realistic estimate than an estimate
based on tolerance level residues. The ARC are estimated to be 0.000356
mg/kg bwt/day and utilize 2.4% of the RfD for the overall U.S.
population. The ARC for children 7-12 years old and children 1-6 years
old (subgroups most highly exposed) are estimated to be 0.000558 mg/kg
bwt/day and 0.001008 mg/kg bwt/day and utilizes 3.7% and 6.7% of the
RfD, respectively. Generally speaking, the 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 100% of the RfD.
Therefore, FMC concludes that the chronic dietary risk of bifenthrin,
as estimated by the aggregate risk assessment, would not exceed the
Agency's level of concern.

    For the overall U.S. population, the calculated MOE at the 95th
percentile

[[Page 27266]]

was estimated to be 719; 386 at the 99th percentile; and 189 at the
99.9th percentile. For all infants < 1-year old, the calculated MOE at
the 95th percentile was estimated to be 531; 186 at the 99th
percentile; and 159 at the 99.9th percentile. For nursing infants < 1-
year old, the calculated MOE at the 95th percentile was estimated to be
1,478; 528 at the 99th percentile; and 233 at the 99.9th percentile.
For non-nursing infants < 1-year old, the calculated MOE at the 95th
percentile was estimated to be 470; 189 at the 99th percentile; and 172
at the 99.9th percentile. For the most highly exposed population
subgroup, children 1-6 years old, the calculated MOE at the 95th
percentile was estimated to be 347; 225 at the 99th percentile; and 104
at the 99.9th percentile. Therefore, FMC concludes that there is
reasonable certainty that no harm will result from acute exposure to
bifenthrin.

    2. Infants and children--i. General. In assessing the potential for
additional sensitivity of infants and children to residues of
bifenthrin, FMC considered data from developmental toxicity studies in
the rat and rabbit, and a 2-generation reproductive 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 to one or both parents. Reproduction
studies provide information relating to effects from exposure to the
pesticide on the reproductive capability of mating animals and data on
systemic toxicity. The Federal Food, Drug, and Cosmetic Act (FFDCA)
section 408 provides that EPA may apply an additional margin of safety
for infants and children in the case of threshold effects to account
for pre- and postnatal toxicity and the completeness of the data base.

    ii. Developmental toxicity studies. In the rabbit developmental
study, there were no developmental effects observed in the fetuses
exposed to bifenthrin. The maternal NOAEL was 2.67 mg/kg/day based on
head and forelimb twitching at the LOAEL of 4 mg/kg/day. In the rat
developmental study, the maternal NOAEL was 1 mg/kg/day, based on
tremors at the LOAEL of 2 mg/kg/day. The developmental (pup) NOAEL was
also 1 mg/kg/day, based upon increased incidence of hydroureter at the
LOAEL (2 mg/kg/day). There were 5/23 (22%) litters affected (5/141
fetuses since each litter only had one affected fetus) in the 2 mg/kg/
day group, compared with zero in the control, 1, and 0.5 mg/kg/day
groups.

    According to recent data (1992-1994) for this strain of rat,
incidence of distended ureter averaged 11% with a maximum incidence of
90%.

    iii. Reproductive toxicity study. In the rat reproduction study,
parental toxicity occurred as decreased bwt at 5.0 mg/kg/day with a
NOAEL of 3.0 mg/kg/day. There were no developmental (pup) or
reproductive effects up to 5.0 mg/kg/day HDT.

    iii. Pre- and postnatal sensitivity-a. Pre-natal. Since there was
not a dose-related finding of hydroureter in the rat developmental
study and in the presence of similar incidences in the recent
historical control data, the marginal finding of hydroureter in rat
fetuses at 2 mg/kg/day (in the presence of maternal toxicity) is not
considered a significant developmental finding. Nor does it provide
sufficient evidence of a special dietary risk (either acute or chronic)
for infants and children which would require an additional safety
factor.

    b. Postnatal. Based on the absence of pup toxicity up to dose
levels which produced toxicity in the parental animals, there is no
evidence of special post-natal sensitivity to infants and children in
the rat reproduction study.

    c. Conclusion. Based on the above, FMC concludes that reliable data
support use of the standard 100-fold uncertainty factor, and that an
additional uncertainty factor is not needed to protect the safety of
infants and children. As stated above, aggregate exposure assessments
utilized less than 10% of the RfD for either the entire U.S. population
or any of the 26 population subgroups including infants and children.
Therefore, it may be concluded that there is reasonable certainty that
no harm will result to infants and children from aggregate exposure to
bifenthrin residues.

F. International Tolerances

     There are no Codex, Canadian, or Mexican residue limits for
residues of residues of bifenthrin in or on the subject commodities.
[FR Doc. 99-12482 Filed 5-18-99; 8:45 am]
BILLING CODE 6560-50-F