[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