Dimethoate - Proposed Pesticide Tolerance for Blueberries 6/95
[Federal Register: June 23, 1995 (Volume 60, Number 121)]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
Dimethoate; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
SUMMARY: EPA proposes to establish an import tolerance for total
residues of the insecticide dimethoate including its oxygen analog in
or on the raw agricultural commodity blueberries. EPA is issuing this
proposal on its own initiative pursuant to a project to harmonize
certain tolerances with those established by the Canadian government.
DATES: Comments, identified by the document control number [OPP-300390], must
be received on or before July 24, 1995.
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. Information submitted
as a comment concerning this notice 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. 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
Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: firstname.lastname@example.org.
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 in 5.1 file format or ASCII file
format. All comments and data in electronic form must be identified by
the docket number [OPP-300390]. No Confidential Business Information
(CBI) should be submitted through e-mail. 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
FOR FURTHER INFORMATION CONTACT: By mail: Robert Forrest, Product
Manager (PM) 14, Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St. SW., Washington, DC
20460. Office location and telephone number: Rm. 219, CM #2, 1921 Jefferson
Davis Hwy., Arlington, VA 22202, (703)-305-6600; e-mail:
SUPPLEMENTARY INFORMATION: Own its own initiative and pursuant to
section 408(e) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21
U.S.C. 346a(e), EPA is proposing to amend 40 CFR 180.204 by
establishing an import tolerance for total residues of the insecticide
dimethoate including its oxygen analog in or on the raw agricultural
commodity blueberries at 1 part per million (ppm). As part of the
Canada-U.S. Trade Agreement (CUSTA), and through the Pesticides
Technical Working Group's Maximum Residue Limit (MRL) Harmonization
Pilot Project, the Canadian government has requested that the U.S.
establish a tolerance of 1 ppm for residues of dimethoate in or on
blueberries. This insecticide is registered for use on blueberries in
Canada, but not in the U.S. The Canadian tolerance is 1 ppm. The Agency
has reviewed Canadian crop field trial residue data and determined that
they are adequate to support an import tolerance. All relevant
materials have been evaluated. The toxicological data considered in
support of the proposed tolerance include:
1. A 3-month feeding study in rats fed diets containing 0, 2, 8,
32, 50, and 400 ppm with a no-observed-effect level (NOEL) for plasma,
red blood cell and brain cholinesterase inhibition of 32 ppm
(equivalent to 1.6 milligrams (mg)/kilogram (kg)/day) and a systemic
NOEL of 50 ppm (equivalent to 2.5 mg/kg/day) based on depressed growth
and food consumption, and increased kidney and liver weights ratios at
the 400-ppm dose level.
2. A 3-month feeding study in dogs fed diets containing 0, 2, 10,
50, 1,500, and 3,000 ppm with a NOEL for red blood cell cholinesterase
inhibition of 2 ppm (equipvalent to 0.05 mg/kg/day) and a NOEL for
systemic effects of 50 ppm (equivalent to 1.25 mg/kg/day) based on
tremors and decreased food consumption in females at the 1,500-ppm dose
3. A 1-year feeding study in dogs fed diets containing 0, 5, 20, or
125 ppm with a NOEL of less than 5 ppm (equivalent to less than 0.18
mg/kg/day) based on decreased brain and red blood cell cholinesterase
in males and decreased liver weight in females at the 5-ppm dose level.
4. A two-generation reproduction study in rats fed diets containing
0, 1, 15, or 65 ppm (equivalent to 0/0, 0.8/0.9, 1.2/1.3, or 5.46/6.04
mg/kg/day for males/females) with a tentative reproductive NOEL of 15
ppm based on decreased fertility in the F1b and F2a, and F2b matings;
decreased pup weight during the lactation period for both sexes and
generations; and decreased live births in the F2b litters.
5. A developmental toxicity study in rats given gavage doses of 0,
3, 6, or 18 mg/kg/day with no developmental toxicity observed under the
conditions of the study. The NOEL for maternal toxcity was established
at 6 mg/kg/day; rats fed 18 mg/kg/day (lowest-effect level) displayed
hpersensitivity, tremors, and unsteady gait.
6. A developmental toxicity study in rabbits given gavage doses of
1, 10, 20, or 40 mg/kg/day from day 7 to day 19 of gestation with a
developmental NOEL of 20 mg/kg/day based on significant reduction in
fetal weight at the 40 mg/kg/day dose level. The maternal NOEL/LEL were
10/20 mg/kg/day based on body weight decrement at 20 mg/kg/day.
7. A 2-year chronic feeding/carcinogenicity study in rats fed diets
containing 0, 5, 25, or 100 ppm (equivalent to 0, 0.25, 1.25, or 5.0
mg/kg/day) with a systemic NOEL of 25 ppm based on increased female
mortality, decreased male body weight gain, anemia in males, and
increased leukocytes in male and female rats at the 100-ppm dose level.
The NOEL for cholinesterase inhibition was established at 5 ppm based
on cholinesterase inhibition at the 25-ppm dose level. In male rats,
there were dose-related trends for (1) spleen hemangiosarcomas
(malignant tumors associated with connective tissue and blood and lymph
vessels); (2) combined spleen hemangioma (benign tumors) and
hemangiosarcoma; and (3) combined spleen hemangioma and
hemangiosarcoma, and skin hemangiosarcoma. Furthermore, there were
significant pair-wise comparisons between control and the high-dose
(100 ppm) for spleen (hemangioma/hemangiosarcoma) and in the combined
tumors of spleen and skin hemangioma/hemangiosarcoma and lymph angioma/
angiosarcoma (benign and malignant tumors made up of lymph vessels).
There was also a significant difference by pair-wise comparison between
the control and low dose (5 ppm) for (1) lymph angiosarcoma, (2)
combined lymph angioma and angiosarcoma, and (3) combined spleen and
skin hemangioma/hemangiosarcoma and lymph angioma/angiosarcoma. There
were no significant tumor increases in female rats.
8. A 78-week carcinogenicity study in B6C3F1 mice fed diets
containing 0, 25, 100, or 200 ppm (equivalent to 0, 3.75, 15, or 30 mg/
kg/day). In male mice there were significant dose-related incrased
trends for (1) combined lung adenoma and/or adenocarcinoma, (2) for
lymphoma, and (3) for the combined group of lymphoma, reticularsarcoma,
and leukemia. In female mice there were significant dose-related trends
for (1) liver carcinoma and for (2) combined liver adenoma and/or
9. Dimethoate is regarded as a mutagenic compound based on the
results of studies designed to determine gene mutation and structural
chromosome aberrations. Dimethoate is a bacterial mutagen and shows
equivocal results for gene mutations in mammalian cells. It produces
clastogenic effects in several studies in vitro and in vivo, and there
are suggestive results for dominant-lethal effects. The National
Toxicology Program has concluded that dimethoate is a mutagenic
compound based on its testing for gene mutation and chromosomal
aberrations. A third category of studies to determine other genotoxic
effects is a data gap for dimethoate.
Dimethoate has been classified as a possible human carcinogen
(category C) by the Office of Pesticide Programs' Health Effects
Division's Peer Review Committee. The Peer Review Committee supports
this classification based on the appearance of equivocal
hemolymphoreticular tumors in male mice, the compound-related (no dose
response) weak effect of combined spleen (hemangioma and
hemangiosarcoma), skin (hemangiosarcoma), and lymph (angioma and
angiosarcoma) tumors in male rats, and positive mutagenic activity
associated with dimethoate.
The Peer Review Committee concluded that the lung tumors seen in
male mice were not biologically significant tumors related to compound
administration since there were no statistically significant
differences based on pair-wise comparisons with controls and each dose
level. The incidence of lung tumors in the control groups was variable,
and there was a high background level of these tumors. The increase in
lymphoma observed in male mice in the high-dose group was of borderline
statistical significance by pair-wise comparison with controls. The
incidence of lymphoma in mice is also common and variable. The
Committee agreed that the increased incidence for the combined
hemolymphoreticular tumors in male mice is compound related, but could
only classify this incidence as equivocal. The incidence
of hemolymphoporeticular tumors in male mice was relatively low and
consistent with historical control, only occurred in one sex (males),
and was evident only in the highdose group.
The Committee concluded that in female mice there were no
significant pair-wise comparisons, there was only the trend with
combined tumors, and the combined incidence was similar to historical
controls. In addition, there also was no evidence of precursor lesions
to carcinogenicity. Regarding the carcinogenicity study in rats, the
Committee concluded that although there were significant pair-wise
comparisons at the low and high doses for all tumors combined, these
tumors did not indicate much more than a weak effect.
EPA has concluded that dimethoate poses no greater than a
negligible cancer risk to humans; therefore, the Agency has chosen to
use reference dose calculations to estimate dietary risk from
dimethoate residues. The dietary risk exposure analysis used a
Reference Dose (RfD) for dimethoate of 0.0005 mg/kg/body weight/day,
based on a NOEL of 0.05 mg/kg/bwt/day for brain cholinesterase
inhibition from a 2-year feeding study in rats, and an uncertainty
factor of 100. The anticipated residue contribution (ARC) for the
general population from published uses and the proposed use on
blueberries utilizes 22 percent of the RfD. The ARC for the most highly
exposed subgroup, nonnursing infants, from published uses and the
proposed use on blueberries, utilizes 57% of the RfD.
The nature of the residue in plants is adequately understood and an
adequate analytical method, gas-liquid chromatography with a thermionic
detector, is available for enforcement purposes. An analytical method
for enforcing this tolerance has been published in the Pesticide
Analytical Manual (PAM), Vol. II. No secondary residues in meat, milk,
poultry, or eggs are expected since blueberries are not considered a
livestock feed commodity.
The pesticide is considered useful for the purpose for which the
tolerance is sought. There are presently 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 180.204
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
Interested persons are invited to submit written comments on the
proposed regulation. Comments must bear a notation indicating the
document control number, [OPP-300390]. All written comments filed in
response to this petition will be available in the Public Response and
Program Resources Branch, at the address given above from 8 a.m. to
4:30 p.m., Monday through Friday, except legal holidays.
A record has been established for this rulemaking under docket
number [OPP-300390] (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 Rm. 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
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: June 15, 1995.
Acting 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. 180.204, by amending paragraph (a) by amending the table
therein to add and alphabetically insert the following commodity, to
read as follows:
Sec. 180.204 Dimethoate including its oxygen analog; tolerances for
(a) * * *
* * * * *
* * * * *
1\There are no U.S. registrations as of (date of publication of final
rule) for dimethoate on blueberries.
* * * * *