[Federal Register Volume 62, Number 14 (Wednesday, January 22, 1997)]
[Notices]
[Pages 3288-3291]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1491]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-690; FRL-5583-3]
Interregional Research Project No. 4; Pesticide Tolerance
Petition Filing
AGENCY: Environmental Protection Agency (EPA).
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SUMMARY: This notice announces the filing of an amendment to pesticide
petition (PP) 5E4598 proposing to extend the effective date for the
time-limited tolerance established for indirect or inadvertent combined
residues of the insecticide imidacloprid and its metabolites resulting
from crop rotational practices in or on the raw agricultural
commodities of the cucurbit vegetables crop group. This notice includes
a summary of the amended petition that was prepared by Bayer
Corporation (Bayer), the registrant, and submitted by the Interregional
Research Project No. 4, the petitioner.
DATES: Comments, identified by the docket number [PF-690], must be
received on or before February 21, 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 by sending
electronic mail (e-mail) to: [email protected] or by
submitting disks. Electronic comments must be submitted either in ASCII
format (avoiding the use of special characters and any form of
encryption) or in WordPerfect in 5.1 file format. All comments and data
in electronic form must be identified by the docket number [PF-690].
Electronic comments on this notice may be filed online at many Federal
Depository Libraries.
Information submitted as comments concerning this document may be
claimed confidential by marking any part or all of that information as
``Confidential Business Information'' (CBI). Information so marked will
not be disclosed except in accordance with procedures set forth in 40
CFR part 2. No CBI should be submitted through e-mail. A copy of the
comment that does
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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.
FOR FURTHER INFORMATION CONTACT: By mail: Hoyt L. Jamerson,
Registration Division (7505W), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location and telephone number: Sixth Floor, Crystal Station #1,
2800 Jefferson Davis Highway, Arlington, VA 22202, (703) 308-8783, e-
mail:[email protected].
SUPPLEMENTARY INFORMATION: EPA has received an amendment to PP 5E4598
from the Interregional Research Project No. 4 (IR-4), New Jersey
Agricultural Experiment Station, P.O. Box 231, Rutgers University, New
Brunswick, NJ 08903. The amended petition proposes, pursuant to section
408 of the Federal Food, Drug and Cosmetic Act (FFDCA), 21 U.S.C. 346a,
to amend 40 CFR 180.472 by extending the effective date to expire on
December 31, 1997, for the time-limited tolerance established for the
indirect or inadvertent combined residues of the insecticide
imidacloprid (1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-
imidazolidinimine) and its metabolites containing the 6-chloropyridinyl
moiety, all expressed as 1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-
imidazolidinimine, resulting from crop rotational practices in or on
the raw agricultural commodities in the cucurbit vegetables crop group
at 0.2 parts per million (ppm). This tolerance will not support
registration for imidacloprid on cucurbit vegetables. EPA will not
consider applications for section 3 or section 24(c) registration for
use of imidacloprid on cucurbit vegetables based on this time-limited
tolerance. The tolerance will allow growers to produce cucurbit
vegetables in rotation with crops that are treated in accordance with
registered uses of imidacloprid. Imidacloprid registrations prohibit
growers from planting crops that lack an imidacloprid tolerance on
ground treated with the insecticide within a 12-month period. Crop
rotational studies indicate that plant back crops grown in fields
treated with imidacloprid may contain measurable amounts of the
pesticide residue, if the rotational crop is planted within 12 months
of application of the pesticide. In some areas, however, it is a common
practice for growers to plant back cucurbit vegetables (melons, squash
and cucumbers) in fields that have been used to produce tomatoes and
peppers. Imidacloprid is registered and tolerances are established for
the fruiting vegetables crop group (including tomatoes and peppers).
IR-4 has submitted PP 6E4766, which proposes a permanent tolerance
for residues of imidacloprid and its metabolites in or on the cucurbit
vegetables crop group at 0.5 ppm. Although PP 6E4766 proposes a
tolerance in support of registration for use of imidacloprid on
cucurbit vegetables, the proposed tolerance, if established, will be
adequate to cover indirect or inadvertent residues on cucurbits
resulting from registered uses of imidacloprid. EPA's evaluation of PP
6E4766 will not be completed in time to establish a permanent
tolerance, prior to the December 31, 1996, expiration date for the
time-limited tolerance. Therefore, IR-4 proposes that the time-limited
tolerance for imidacloprid be extended to December 31, 1997, to allow
EPA additional time to review IR-4's petition for permanent tolerance
for residues of imidacloprid on cucurbit vegetables.
As required by section 408(d) of the FFDCA, as recently amended by
the Food Quality and Protection Act IR-4 included in the amendment a
summary of the petition provided by Bayer 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; EPA, as
mentioned above, 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. Plant Metabolism and Analytical Method
The nature of the imidacloprid residue in plants and livestock is
adequately understood. The residues of concern are combined residues of
imidacloprid and it metabolites containing the 6-chloropyridinyl
moiety, all calculated as imidacloprid. 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. There is
an additional confirmatory method available. Imidacloprid and its
metabolites have been shown to be stable for at least 24 months in
frozen storage.
B. Toxicological Profile of Imidacloprid
1. Acute toxicity. The acute oral LD50 values for imidacloprid
technical ranged from 424 to 475 milligrams (mg)/kilogram (kg) body
weight (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/
cubic meter (m3) air (aerosol). Imidacloprid was not irritating to
rabbit skin or eyes. Imidacloprid did not cause skin sensitization in
guinea pigs.
2. Genotoxicity. 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 two-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. Ninety-day feeding studies were conducted
in rats and dogs. The NOEL's for these tests were 14 mg/kg bwt/day (150
ppm) and 5 mg/kg bwt/day (200 ppm) for the rat and dog studies,
respectively.
5. Chronic toxicity/oncogenicity. 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 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.
6. Endocrine effects. The toxicology database for imidacloprid is
current and complete. Studies in this database include evaluation of
the potential effects on reproduction and development, and an
evaluation of the pathology of the endocrine organs following short- or
long-term exposure. These studies revealed no primary endocrine effects
due to imidacloprid.
7. Mode of action. Imidacloprid exhibits a mode of action different
from
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traditional organophosphate, carbamate, or pyrethroid insecticides.
Imidacloprid acts by binding to the nicotinergic receptor sites at the
postsynaptic membrane of the insect nerve. Due to this novel mode of
action, imidacloprid has not shown any cross resistance to registered
alternative insecticides.
C. Aggregate Exposure
Imidacloprid is a broad-spectrum insecticide with 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. Those potential exposures are addressed below:
1. Dietary. 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. As published in the Federal Register of December 13, 1995
(60 FR 64006) and June 12, 1996 (61 FR 2674) (petition to establish
tolerances on leafy green vegetables (PP 5F4522/R2237)), the
theoretical maximum residue contribution (TMRC) from published uses is
0.008358 mg/kg/bwt/day utilizing 14.7 percent of the RfD for the
general population. For the most highly exposed subgroup in the
population, non-nursing infants (<1 year old), the TMRC for the
published tolerances is 0.01547 mg/kg/day. This is equal to 27.1
percent of the RfD. Therefore, Bayer believes that dietary exposure
from the existing uses (including this time-limited tolerance) will not
exceed the reference dose for any subpopulation (including infants and
children).
2. Water. Although the various imidacloprid labels contain a
statement that this chemical demonstrates the properties associated
with chemicals detected in groundwater, Bayer is not aware of
imidacloprid being detected in any wells, ponds, lakes, streams, etc.
from its use in the United States. In studies conducted in 1995,
imidacloprid was not detected in 17 wells on potato farms in Quebec,
Canada. In addition, groundwater monitoring studies are currently
underway in California and Michigan. Therefore, Bayer believes that
contributions to the dietary burden from residues of imidacloprid in
water would be inconsequential.
3. Non-occupational-- a. 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 are young
children. Margins of safety (MOS) of 7,587 to 41,546 for 10-year-old
children and 6,859 to 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 to 38.2
micrograms (g)/square centimeter (cm2) and for 5-year-old
children from 5.1 to 33.5 g/cm2. This compares with the
average imidacloprid transferable residue level of 0.080 g/
cm2 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.
b. 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 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 107 and 2.4 x 108, respectively - and exposure can thus
be considered negligible.
c. 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 percent 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/m3, it is apparent that exposure to
imidacloprid from smoking (direct and/or indirect exposure) would not
be significant.
d. Pet treatment. Human exposure from the use of imidacloprid to
treat dogs and cats for fleas has been addressed by EPA's Occupational
and Residential Exposure Branch 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.
4. Cumulative effects. No other chemicals having the same mechanism
of toxicity are currently registered, therefore, Bayer believes that
there is no risk from cumulative effects from other substances with a
common mechanism of toxicity.
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, Bayer concludes that total aggregate
exposure to imidacloprid from all current uses including those
currently proposed will utilize little more than 15 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, Bayer concludes 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 two-
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, Bayer surmises 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.
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Using the conservative exposure assumptions described above, EPA
has concluded that the TMRC from use of imidacloprid from published
uses is 0.008358 mg/kg/bwt/day utilizing 14.7 percent of the RfD for
the general population. For the most highly exposed subgroup in the
population, non-nursing infants (<1 year old), the TMRC for the
published tolerances is 0.01547 mg/kg/day. This is equal to 27.1
percent of the RfD. Therefore, Bayer concludes that dietary exposure
from the existing uses including the currently proposed tolerances will
not exceed the reference dose for any subpopulation (including infants
and children).
E. Other Considerations
There is no reasonable expectation that secondary residues will
occur in milk and eggs, or meat, fat, and meat byproducts of livestock
or poultry; there are no livestock feed items associated with the
cucurbit vegetables.
F. International Tolerances
No CODEX Maximum Residue Levels (MRL's) have been established for
residues of Imidacloprid on any crops at this time.
II. Public Record
EPA invites interested persons to submit comments on this notice of
filing. Comments must bear a notification indicating the docment number
[PF-690].
A record has been established for this notice of filing under
docket number [PF-690] (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 4:00 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:
[email protected]
Electronic comments must be submitted as an 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 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: January 10, 1997.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 97-1491 Filed 1-21-97; 8:45 am]
BILLING CODE 6560-50-F