Imidacloprid - Proposed Time-Limited Tolerance on Cucurbits 12/95
[Federal Register: December 13, 1995 (Volume 60, Number 239)]
[Rules and Regulations]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[PP 5E4598/P638; FRL-4990-5]
Imidacloprid; Pesticide Tolerances 11/95
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
SUMMARY: EPA proposes to establish a time-limited tolerance for
indirect or inadvertent combined residues of the insecticide (1-[6-
chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine (referred to in
this document as imidacloprid) and its metabolites resulting from crop
rotational practices in or on the raw agricultural commodities in the
cucurbit vegetables crop group. The proposed regulation to establish a
maximum permissible level for residues of the insecticide was requested
in a petition submitted by the Interregional Research Project No. 4
(IR-4) pursuant to the Federal Food, Drug and Cosmetic Act (FFDCA). The
time-limited tolerance would expire on December 31, 1996.
DATES: Comments, identified by the document control number [PP 5E4598/
P638], must be received on or before January 12, 1996.
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 Hwy., Arlington, VA 22202. Comments and data may
also be submitted electronically by sending electronic mail (e-mail)
to: email@example.com. 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 ASCII file format. All comments and data in
electronic form must be identified by the docket number [PP 5E4425/P638].
Electronic comments on this proposed rule may be filed online at many Federal
Depository Libraries. Additional information on electronic submissions can be
found below in this document.
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 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 a.m. to 4:30 p.m., Monday through Friday, excluding legal
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:
SUPPLEMENTARY INFORMATION: The Interregional Research Project No. 4
(IR-4), New Jersey Agricultural Experiment Station, P.O. Box 231,
Rutgers University, New Brunswick, NJ 08903, has submitted pesticide
petition (PP) 5E4598 to EPA on behalf of the Agricultural Experiment
Stations of California, Florida, Georgia, South Carolina, and Texas.
The petition requests that the Administrator, pursuant to section
408(e) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C.
346a(e), amend 40 CFR 180.472 by establishing a tolerance for 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
resulting from crop rotational practices in or on the raw agricultural
commodities in the cucurbit vegetables crop group at 0.2 part per
The proposed tolerance will not support registration for
imidacloprid on cucurbit vegetables. EPA will not consider applications
for section 3 or section 24(c) registration of imidacloprid on cucurbit
vegetables based the proposed time-limited tolerance. The tolerance
would 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 which lack an imidacloprid tolerance on ground treated with the
insecticide within a 12-month period. 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). There are no established imidacloprid tolerances,
however, for the cucurbit vegetables. Crop rotational studies reviewed
by EPA 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
Currently, growers who plan to double crop with cucurbit vegetables
must not use imidacloprid, or they must not plant back cucurbit
vegetables in fields treated within 12 months of application with
imidacloprid. According to the University of Florida Cooperative
Extension Service, the inability to double crop because of the
imidacloprid plant-back restriction will have a serious financial
impact on the South Florida vegetable industry. Approximately 12,000
acres in South Florida are double cropped with cucurbit vegetables.
Much of this acreage has been treated with imidacloprid to control
sweet potato whitefly (silverleaf whitefly) on tomatoes. Prior to
registration of imidacloprid on tomatoes, EPA approved emergency
exemptions under Section 18 of Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA) for its use in California, Florida, South
Carolina, and Texas to avert significant economic loss from sweet
potato white fly damage.
The proposed tolerance, which would expire on December 31, 1996,
should allow IR-4 sufficient time to submit a permanent tolerance for
imidacloprid on cucurbit vegetables. IR-4 is developing field residue
data in support of a permanent tolerance and registration for use of
imidacloprid on cucurbit vegetables. The permanent tolerance will be
proposed by IR-4 to cover residues in cucurbit vegetables from
application to the growing crop, as well as crop rotational practices.
EPA's policy is to consider tolerance petitions, when requested by
the registrants or any interested parties, for pesticide residues on
replacement or rotational crops when residues result from pesticide
carryover in soil from treatment of previous crops. Such tolerances
will be set at levels determined to be appropriate based on evaluations
of toxicity and residue data submitted to the Agency by the petitioner.
Guidance on how to conduct residue studies on rotation crops can be
found in the EPA publication "Pesticide Reregistration Reject Rate
Analysis Residue Chemistry/Environmental Fate Follow Up Guidance for
Conducting Rotational Crop Studies," February 1993. The procedures for
filing a petition, as described in 40 CFR 180.7, should be followed,
and each petition must be accompanied by the appropriate fee, as
specified in 40 CFR 180.33.
The toxicological data considered in support of the proposed
1. A 1-year chronic feeding study in dogs fed diets containing 0,
200, 500, or 1,250/2,500 ppm (average intake was 0, 6.1, 15, or 41/72
milligrams (mg)/kilogram (kg)/day) with a no-observed-effect level of
1,250 ppm based on increased plasma cholesterol and liver cytochrome P-
450 levels in dogs at the 2,500-ppm dose level. The high dose was
increased to 2,500 ppm (72 mg/kg/day) from week 17 onward due to lack
of toxicity at the 1,250-dose level.
2. A 2-year feeding/carcinogenicity study in rats fed diets
containing 0, 100, 300, 900, or 1,800 ppm with a NOEL for chronic
effects at 100 ppm (5.7 mg/kg/day in males, 7.6 mg/kg/day in females)
that included decreased body weight gain in females at 300 ppm (24.9
mg/kg/day) and above; and increased thyroid lesions in males at 300 ppm
(16.9 mg/kg/day) and above, and in females at 900 ppm (73 mg/kg/day)
and above. There were no apparent carcinogenic effects under the
conditions of the study.
3. A 2-year carcinogenicity study in mice fed diets containing 0,
100, 330, 1,000, or 2,000 ppm with a NOEL of 1,000 ppm (208 mg/kg/day
in males, 274 mg/kg/day in females) based on decreased food consumption
and decreased water intake at the 2,000-ppm dose level. There were no
apparent carcinogenic effects observed under the conditions of this
4. A three-generation reproduction study with rats fed diets
containing 0, 100, 250, or 700 ppm with a reproductive no-observed-
effect level (NOEL) of 100 ppm (equivalent to 8 mg/kg/day based on decreased
pup body weight observed at the 250-ppm dose level.
5. A developmental toxicity study in rat given gavage doses at 0,
10, 30, or 100 mg/kg/day during gestation days 6 to 16 with a NOEL for
developmental toxicity at 30 mg/kg/day based on increased wavy ribs
observed at the 100- mg/kg/day dose level.
6. A developmental toxicity study in rabbits given gavage doses at
0, 8, 24, or 72 mg/kg/day during gestation days 6 through 19 with a
NOEL for developmental toxicity at 24 mg/kg/day based on decreased body
weight and increased skeletal abnormalities observed at the 72-mg/kg/
day dose level.
7. Imidacloprid was negative for mutagenic effects in all but two
of 23 mutagenic assays. Imidacloprid tested positive for chromosome
aberrations in an in vitro cytogenetic study with human lymphocytes for
the detection of induced clastogenic effects, and for genotoxicity in
an in vitro cytogenetic assay measuring sister chromatid exchange in
Chinese hamster ovary cells.
Dietary risk assessments for imidacloprid indicate that there is
minimal risk from established tolerances and the proposed tolerance for
cucurbit vegetables. A cancer risk assessment is not appropriate for
imidacloprid since the pesticide is assigned to "Group E" (no
evidence of carcinogenicity) of EPA's cancer classification system.
Dietary risk assessments for the pesticide were conducted using the
Reference Dose (RfD) to assess chronic exposure and risk.
The RfD is calculated at 0.057 mg/kg/of body weight/day based on a
NOEL of 5.7 mg/kg/day from the 2-year rat feeding/carcinogenicity study
and 100-fold uncertainty factor. The theoretical maximum residue
contribution (TMRC) from existing tolerances utilizes less than 15
percent of the RfD for the general population and less than 30 percent
of the RfD for nonnursing infants less than 1 year in age. The proposed
tolerance for cucurbit vegetables would utilize less than 1 percent of
the RfD for the general population and all population subgroups.
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
The metabolism of imidacloprid in plants and livestock is
adequately understood. The residues of concern are combined residues of
imidacloprid and its 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-chloropyridiyl moiety using a permanganate oxidation, silyl
derivatization, and capillary GC-MS selective ion monitoring.
There are currently no actions pending against the continued
registration of this chemical.
Based on the information and data considered, the Agency has
determined that the tolerance established by amending 40 CFR 180 would
protect the public health. Therefore, it is proposed that the tolerance
be established as set forth below.
Any person who has registered or submitted an application for
registration of a pesticide, under the Federal Insecticide, Fungicide,
and Rodenticide Act (FIFRA) as amended, which contains any of the
ingredients listed herein, may request within 30 days after publication
of this notice in the Federal Register that this rulemaking proposal be
referred to an Advisory Committee in accordance with section 408(e) of
A record has been established for this rulemaking under docket
number [PP 5E4598/P638] (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 a.m. to 4:30 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:
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 rulemaking, 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 rulemaking record which will also include all comments
submitted directly in writing. The official rulemaking record is the
paper record maintained at the address in "ADDRESSES" at the
beginning of this document.
Under Executive Order 12866 (58 FR 51735, Oct. 4, 1993), the Agency
must determine whether the regulatory action is "significant" and
therefore subject to all the requirements of the Executive Order (i.e.,
Regulatory Impact Analysis, review by the Office of Management and
Budget (OMB)). Under section 3(f), the order defines "significant" as
those actions likely to lead to a rule (1) having an annual effect on
the economy of $100 million or more, or adversely and materially
affecting a sector of the economy, productivity, competition, jobs, the
environment, public health or safety, or State, local or tribal
governments or communities (also known as "economically
significant"); (2) creating serious inconsistency or otherwise
interfering with an action taken or planned by another agency; (3)
materially altering the budgetary impacts of entitlement, grants, user
fees, or loan programs; or (4) raising novel legal or policy issues
arising out of legal mandates, the President's priorities, or the
principles set forth in this Executive Order.
Pursuant to the terms of this Executive Order, EPA has determined
that this rule is not "significant" and is therefore not subject to
Pursuant to the requirements of the Regulatory Flexibility Act
(Pub. L. 96-354, 94 Stat. 1164, 5 U.S.C. 601-612), the Administrator
has determined that regulations establishing new tolerances or raising
tolerance levels or establishing exemptions from tolerance requirements
do not have a significant economic impact on a substantial number of
small entities. A certification statement to this effect was published
in the Federal Register of May 4, 1981 (46 FR 24950).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
Dated: November 30, 1995.
Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.
Therefore, it is proposed that 40 CFR part 180 be amended as
1. The authority citation for part 180 continues to read as
Authority: 21 U.S.C. 346a and 371.
2. In Sec. 180.472, by adding new paragraph (f), to read as
Sec. 180.472 1-[(6-Chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine;
tolerances for residues.
* * * * *
(f) Time-limited indirect or inadvertent tolerance: A time-limited
tolerance, to expire on December 31, 1996, is established for indirect
or inadvertent combined residues of the insecticide 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, when present therein
as a result of the application of the pesticide to growing crops listed
in this section and other nonfood crops as follows:
Vegetables, cucurbit....................................... 0.2