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Imidacloprid - Pesticide Petition Filing 12/97

[Notices]
[Page 66077-66083]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17de97-72]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-781; FRL-5758-3]
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-781, must
be received on or before January 16, 1998.
ADDRESSES: By mail submit written comments to: Public Information and
Records Integrity Branch, Information Resources and Services Division
(7502C), 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 to: opp-
docket@epamail.epa.gov. Follow 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: The product manager listed in the
table below:

------------------------------------------------------------------------
                                   Office location/
        Product Manager            telephone number          Address
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James Tompkins (PM 25)........  Rm. 265, CM #2, 703-    1921 Jefferson
                                 305-7801, e-            Davis Hwy,
                                 mail:tompkins.james@e   Arlington, VA
                                 pamail.epa.gov.
Elizabeth Haeberer............  Rm. 207, CM #2, 703-    Do.
                                 308-2891, e-mail:
                                 haeberer.elizabeth@ep
                                 amail.epa.gov.
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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-781]

[[Page 66078]]

(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-781 and appropriate petition number.
Electronic comments on 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: December 4, 1997

Peter Caulkins,

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.

1. Bayer Corporation

PP 5F4480

    EPA has received a pesticide petition (PP 5F4480) from Bayer
Corporation, 8400 Hawthorn Rd., P.O. Box 4913, Kansas City, MO 64120-
0013. proposing pursuant to section 408(d) of the Federal Food, Drug
and Cosmetic Act, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by
establishing a tolerance for residues of imidacloprid in or on the raw
agricultural commodity pecans at 0.05 parts per million (ppm). The
proposed analytical method involves homogenization, filtration,
partition and cleanup with analysis by high performance liquid
chromatography using UV detection. EPA has determined that the petition
contains data or information regarding the elements set forth in
section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated
the sufficiency of the submitted data at this time or whether the data
supports granting of the petition. Additional data may be needed before
EPA rules on the petition.

A. Residue Chemistry

    1. Plant metabolism. The metabolism of imidacloprid in plants is
adequately understood for the purposes of these tolerances. The
residues of concern are combined residues of imidacloprid and its
metabolites containing the 6-chloro-pyridinyl moiety, all calculated as
imidacloprid.
    2. Analytical method. The analytical method is a common moiety
method for imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety using a permanganate oxidation, silyl
derivatization, and capillary GC-MS selective ion monitoring. This
method has successfully passed a petition method validation in EPA
labs. There is a confirmatory method specifically for imidacloprid and
several metabolites utilizing GC/MS and HPLC-UV which has been
validated by the EPA as well. Imidacloprid and its metabolites are
stable for at least 24 months in the commodities when frozen.
    3. Magnitude of residues. Field studies were conducted to determine
imidacloprid residues on pecans following treatment with either a
single soil or two foliar applications. Seven field studies were
conducted using a single soil application of 0.5 lb active ingredient
per acre. 5-field studies were conducted using two foliar applications
at a rate of 0.17 lb active ingredient per acre, with a 10-day
interval. After the final foliar application or the soil application,
samples were collected at earliest harvest which ranged from 4 to 21-
days for the foliar application or 99 to 150 days for the soil
application. Maximum residues, in pecans, detected following either 2
foliar applications or 1 soil application were >0.05 ppm. Therefore, a
tolerance of 0.05 ppm of pecans is being proposed with a preharvest
interval defined as earliest harvest (shuck split). CBTS has concluded
that existing poultry meat and egg tolerances are adequate to support
the proposed new uses of imidacloprid.

B. Toxicological Profile

    1. Acute toxicity. The acute oral LD50 values for
imidacloprid technical ranged from 424 - 475 milligrams/kilogram/
bodyweight (mg/kg/bwt) in the rat. The acute dermal LD50 was
greater than 5,000 mg/kg in rats. The 4-hour rat inhalation
LC50 was >69 mg/m**3 air (aerosol). Imidacloprid
was not irritating to rabbit skin or eyes. Imidacloprid did not cause
skin sensitization in guinea pigs.
    2. Genotoxicty. Extensive mutagenicity studies conducted to
investigate point and gene mutations, DNA damage and chromosomal
aberration, both using in vitro and in vivo test systems show
imidacloprid to be non-genotoxic.
    3. Reproductive and developmental toxicity. A 2-generation rat
reproduction study gave a no-observed-effect level (NOEL) of 100 ppm (8
mg/kg/bwt). Rat and rabbit developmental toxicity studies were negative
at doses up to 30 mg/kg/bwt and 24 mg/kg/bwt, respectively.
    4. Subchronic toxicity. 90-day feeding studies were conducted in
rats and dogs. The NOEL's for these tests were 14 milligrams/kilogram/
bodyweight/day (mg/kg/bwt/day) (150 pm) 5 mg/kg/bwt/day (200 ppm) for
the rat and dog studies respectively.
    5. Chronic toxicity. A 2-year rat feeding/carcinogenicity study was
negative for carcinogenic effects under the conditions of the study and
had a NOEL of 100 ppm (5.7 mg/kg/bwt in male and 7.6 mg/kg/bwt female)
for noncarcinogenic effects that included decreased body weight gain in
females at 300 ppm and increased thyroid lesions in males at 300 ppm
and females at 900 ppm. A 1-year dog feeding study indicated a NOEL of
1,250 ppm (41 mg/kg/bwt). A 2-year mouse carcinogenicity study that was
negative for carcinogenic effects under conditions of the study and
that had a NOEL of 1,000 ppm 208 milligrams/kilogram/day (mg/kg/day).
    Imidacloprid has been classified under "Group E" (no evidence of
carcinogenicity) by EPA's OPP/HED's Reference Dose (RfD) Committee.
There is no cancer risk associated with exposure to this chemical. The
reference dose (RfD) based on the 2-year rat feeding/carcinogenic study
with a NOEL of 5.7 mg/kg/bwt and 100-fold uncertainty factor, is
calculated to be 0.057 mg/kg/bwt. The theoretical maximum residue
contribution (TMRC) from published uses is 0.008187 mg/kg/bwt/day
utilizing 14.4% of the RfD.
    6. Animal metabolism. The metabolism of imidacloprid in animals

[[Page 66079]]

is adequately understood. The residues of concern are combined residues
of imidacloprid and its metabolites containing the 6-chloro-
pyridinylmoiety, all calculated as imidacloprid.

C. Aggregate Exposure

    Imidacloprid is a broad-spectrum insecticide with excellent
systemic and contact toxicity characteristics with both food and non-
food uses. Imidacloprid is currently registered for use on various food
crops, tobacco, turf, ornamentals, buildings for termite control, and
cats and dogs for flea control.
    1. Dietary exposure. The EPA has determined that the reference dose
(RfD) based on the 2-year rat feeding/carcinogenic study with a NOEL of
5.7 mg/kg/bwt and 100-fold uncertainty factor, is calculated to be
0.057 mg/kg/bwt.
    2. Food. The theoretical maximum residue contribution (TMRC) from
this proposed use on Pecans as well as all published uses and pending
uses is 0.008149 mg/kg/bwt/day utilizing 14.3% of the RfD for the
general population. For the most highly exposed subgroup in the
population, children (1-6 years), the TMRC for the all uses is 0.018367
mg/kg/day. This is equal to 32.2% of the RfD. Therefore, dietary
exposure from the existing uses including the currently proposed
tolerance will not exceed the reference dose for any subpopulation
(including infants and children).
    3. Drinking water. Although the various imidacloprid labels contain
a statement that this chemical demonstrates the properties associated
with chemicals detected in ground water, the Registrant is not aware of
imidacloprid being detected in any wells, ponds, lakes, streams, etc.
from its use in the U.S. In studies conducted in 1995, imidacloprid was
not detected in 17 wells on potato farms in Quebec, Canada. In
addition, ground water monitoring studies are currently underway in
California and Michigan. Therefore, contributions to the dietary burden
from residues of imidacloprid in water would be inconsequential.
    4. Non-dietary exposure-- i. Residential turf. Bayer has conducted
an exposure study to address the potential exposures of adults and
children from contact with imidacloprid treated turf. The population
considered to have the greatest potential exposure from contact with
pesticide treated turf soon after pesticides are applied is young
children. Margins of safety (MOS) of 7,587 - 41,546 for 10-year-old
children and 6,859 - 45,249 for 5-year-old children were estimated by
comparing dermal exposure doses to the imidacloprid no-observable
effect level of 1,000 mg/kg/day established in a 15-day dermal toxicity
study in rabbits. The estimated safe residue levels of imidacloprid on
treated turf for 10-year-old children ranged from 5.6 - 38.2 g/
cm**2 and for 5-year-old children from 5.1 - 33.5 g/
cm**2. This compares with the average imidacloprid
transferable residue level of 0.080 g/cm**2 present
immediately after the sprays have dried. These data indicate that
children can safely contact imidacloprid-treated turf as soon after
application as the spray has dried.
    ii. Termiticide. Imidacloprid is registered as a termiticide. Due
to the nature of the treatment for termites, exposure would be limited
to that from inhalation and was evaluated by EPA's Occupational and
Residential Exposure Branch (OREB) and Bayer. Data indicate that the
Margins of Safety for the worst case exposures for adults and infants
occupying a treated building who are exposed continuously (24 hours/
day) are 8.0 x 10**7 and 2.4 x 10**8,
respectively - and exposure can thus be considered negligible.
    iii. Tobacco smoke. Studies have been conducted to determine
residues in tobacco and the resulting smoke following treatment.
Residues of imidacloprid in cured tobacco following treatment were a
maximum of 31 ppm (7 ppm in fresh leaves). When this tobacco was burned
in a pyrolysis study only 2% of the initial residue was recovered in
the resulting smoke (main stream plus side stream). This would result
in an inhalation exposure to imidacloprid from smoking of approximately
0.0005 mg per cigarette. Using the measured subacute rat inhalation
NOEL of 5.5 mg/m**3, it is apparent that exposure to
imidacloprid from smoking (direct and/or indirect exposure) would not
be significant.
    iv. Pet treatment. Human exposure from the use of imidacloprid to
treat dogs and cats for fleas has been addressed by EPA's OREB who have
concluded that due to the fact that imidacloprid is not an inhalation
or dermal toxicant and that while dermal absorption data are not
available, imidacloprid is not considered to present a hazard via the
dermal route.

D. Safety Determination

    1. U.S. population. 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
imidacloprid from all current uses including those currently proposed
will utilize little more than 15% of the RfD for the U.S. population.
EPA generally has no concerns for exposures below 100% 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 imidacloprid
residues.
    2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of imidacloprid, the
data from developmental studies in both rat and rabbit and a 2-
generation reproduction study in the rat have been considered. The
developmental toxicity studies evaluate potential adverse effects on
the developing animal resulting from pesticide exposure of the mother
during prenatal development . The reproduction study evaluates effects
from exposure to the pesticide on the reproductive capability of mating
animals through two generations, as well as any observed systemic
toxicity.
    FFDCA section 408 provides that EPA may apply an additional safety
factor for infants and children in the case of threshold effects to
account for pre- and post- natal effects and the completeness of the
toxicity database. Based on current toxicological data requirements,
the toxicology database for imidacloprid relative to pre- and post-
natal effects is complete. Further for imidacloprid, the NOEL of 5.7
mg/kg/bwt from the 2-year rat feeding/ carcinogenic study, which was
used to calculate the RfD (discussed above), is already lower than the
NOELs from the developmental studies in rats and rabbits by a factor of
4.2 to 17.5 times. Since a 100-fold uncertainty factor is already used
to calculate the RfD, it is surmised that an additional uncertainty
factor is not warranted and that the RfD at 0.057 mg/kg/bwt/day is
appropriate for assessing aggregate risk to infants and children.
    Using the conservative exposure assumptions described above, it can
be concluded that the TMRC from use of imidacloprid from published and
pending uses is 0.008149 mg/kg/bwt/day utilizing 14.3% of the RfD for
the general population. For the most highly exposed subgroup in the
population, children (1-6 years), the TMRC for the published tolerances
is 0.018367 mg/kg/day. This is equal to 32.2% of the RfD. Therefore,
dietary exposure from the existing uses including the currently
proposed tolerances will not exceed the reference dose for any
subpopulation (including infants and children).

[[Page 66080]]

E. International Tolerances

    No CODEX Maximum Residue Levels (MRL's) have been established for
residues of Imidacloprid on any crops at this time.   (Elizabeth
Haeberer)

 [FR Doc. 97-32935 Filed 12-16-97; 8:45 am]
BILLING CODE 6560-50-F