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Dimethoate - Proposed Pesticide Tolerance for Asparagus 6/95

[Federal Register: July 5, 1995 (Volume 60, Number 128)]
40 CFR Part 180
[PP 4E4374/P617; FRL-4961-9]
Rin 2070-AC18
Dimethoate; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.

SUMMARY: This document proposes that a tolerance be established for
residues of the insecticide dimethoate in or on the raw agricultural
commodity asparagus. The Interregional Research Project No. 4 (IR-4)
requested this proposed regulation to establish a maximum permissible
level for residues of the insecticide in or on the commodity in a
petition submitted pursuant to the Federal Food, Drug and Cosmetic Act

DATE: Comments, identified by the document control number [PP 4E4374/P617],
must be received on or before August 4, 1995.

ADDRESSES: By mail, submit written comments to EPA's Office of
Pesticide Programs (OPP) at: 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 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 holidays.
    Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: 
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 [PP 4E4374/P617]. 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 this document.

FOR FURTHER INFORMATION CONTACT: By mail: Hoyt L. Jamerson, Emergency Response
and Minor Use Section (7505W), Registration Division, 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 4E4374 to EPA on behalf of the Agricultural Experiment
Stations of North Carolina and Oklahoma. The petition requested that
the Administrator, pursuant to section 408(e) of the Federal Food,
Drug, and Cosmetic Act (21 U.S.C. 346a(e)), amend 40 CFR 180.204 to
establish a tolerance for residues of the pesticide dimethoate (O,O-
dimethyl S-(N-methylcarbamoylmethyl) phosphorodithioate) including its
oxygen analog (O,O-dimethyl S-(N-methylcarbamoylmethyl)
phosphorothioate) in or on the raw agricultural commodity asparagus at
0.15 part per million (ppm). The petitioner proposed that use of
dimethoate on asparagus be geographically limited to exclude California
and Arizona based on the geographical representation of the residue
data submitted. Additional residue data will be required to expand the
area of usage. Persons seeking geographically broader registration
should contact the Agency's Registration Division at the address
provided above.
    The data submitted in the petition and other relevant material 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) 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 weight ratios at the
400-ppm dose level.
    2. A 3-month feeding study in dogs fed diets containing 0, 2, 10,
50, and 1,500 ppm with a NOEL for red blood cell cholinesterase
inhibition of 2 ppm (equivalent 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 for cholinesterase inhibition of less than 5 ppm
(equivalent to less than 0.18 mg/kg/day) based on decreased brain and
red blood cell cholinesterase at the 5-ppm dose level and a systemic
NOEL of less than 5 ppm based on 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, 0.08/0.09, 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 toxicity was established
at 6 mg/kg/day; rats fed 18 mg/kg/day (lowest-effect level) displayed
hypersensitivity, tremors, and unsteady gait.
    6. A developmental toxicity study in rabbits given gavage doses of
0, 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 was
established at 10 mg/kg/day based on body weigth decrement at 20 mg/kg/
day dose level.
    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 increased
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
    Dimethoate has been classified as a possible human carcinogen
(category C) by the Office of Pesticide Programs' Health Effects
Division's Carcinogenicity 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
hemolymphoreticular tumors in male mice was relatively low and
consistent with historical control, only occurred in one sex (males),
and was evident only in the high-dose 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 reference dose (RfD) for dimethoate is
established at 0.0005 mg/kg body weight/day. The RfD is 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 asparagus utilizes 21 percent of the RfD.
The ARC for the subgroup most highly exposed, nonnursing infants,
utilizes 41 percent of the RfD based on published uses and the proposed
use on asparagus. The dietary risk assessment indicates that there is
no appreciable risk from the establishment of the proposed tolerance
for asparagus.
    The nature of the residue in plants is adequately understood and an
adequate analytical method, gas chromatography with a flame photometric
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 asparagus is not considered a
livestock feed commodity. There are presently no actions pending
against the continued registration of this chemical.
    Based on the above information considered by the Agency 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 document in the Federal Register that this rulemaking proposal
be referred to an Advisory Committee in accordance with section 408(e)
of the Federal Food, Drug, and Cosmetic Act.
    A record has been established for this rulemaking under docket
number [PP 4E4374/P617] (including any 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.
    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
OMB review.
    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

    Administrative practice and procedure, Agricultural commodities,
Pesticides and pests, Reporting and recordkeeping requirements.

    Dated: June 23, 1995

Peter Caulkins,

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 follows:

    Authority: 21 U.S.C. 346a and 371.

    2. In Sec. 180.204, paragraph (b) is amended in the table therein
by adding and alphabetically inserting a new entry, to read as follows:

Sec. 180.204   Dimethoate including its oxygen analog; tolerances for

*      *      *      *      *
    (b) *  *  *

                                                              Parts per
                         Commodity                             million
Asparagus..................................................      0.15
                  *        *        *        *        *