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Diquat Dibromide - Proposed Pesticide Tolerances 3/96

[Federal Register: March 27, 1996 (Volume 61, Number 60)]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[PP 4E4365 and 4E4376/P645; FRL-5348-1]
RIN 2070-AB18
Diquat; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.

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SUMMARY: This document proposes to establish a tolerance for the plant
growth regulator diquat [6,7-dihydrodipyrido (1,2-a:2',1'-c)
pyrazinediium] derived from application of the dibromide salt and
calculated as the cation in or on the imported raw agricultural
commodities bananas and coffee at 0.05 part per million (ppm). Zeneca,
Inc., petitioned for this proposed regulation to establish a maximum
permissible level for the residues of the plant growth regulator.

DATES: Comments identified by the docket number, (PP 4E4365 and 4E4376/
P645), must be received on or before April 26, 1996.

ADDRESSES:  Submit written comments by mail 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: Public Docket, Rm.
1132, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: opp-docket@epamail.epa.gov. 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 in 5.1 file format or ASCII file
format. All comments and data in electronic form must be identified by
the docket number (PP 4E4365 and 4E4376/P645). 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.
    Information submitted as a comment concerning this document may be
claimed confidential by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures as 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 will be included in the
public docket by EPA without prior notice. The public docket is
available for public inspection in Rm. 1132 at the above address, from
8 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT:  By mail: Joanne I. Miller, Product
Manager (PM-23), Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW., Washington,
DC 20460. Office location, telephone number, and e-mail address: Rm.
237, CM #2, 1921 Jefferson Davis Highway, Arlington, VA, (703)-305-6224;
e-mail:  miller.joanne@epamail.epa.gov.

SUPPLEMENTARY INFORMATION: Zeneca, Inc., P.O. Box 15458, Wilmington, DE
19850, has submitted pesticide petition (PP 4E4365 and 4E4376) to EPA.
This petition requested that the Administrator, pursuant to the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e), establish a
tolerance for residues of the plant growth regulator diquat [6,7-
dihydrodipyrido (1,2-a:2',1'-c) pyrazinediium derived from application
of the dibromide salt and calculated as the cation in or on the raw
agricultural commodity bananas at 0.02 ppm and coffee at 0.05 ppm. The
petition for bananas was subsequently amended to raise the tolerance
level to 0.05 ppm.
    The data submitted in the petition and other relevant material have
been evaluated. The toxicological data considered in support of the
tolerances include the following:
    1. A 2-year chronic toxicity/carcinogenicity study in rats resulted
in a systemic lowest-observed-effect level (LOEL) of 2.91 mg/kg/day in
males and 3.64 mg/kg/day in females (expressed as diquat cation), and a
systemic no-observed effect level (NOEL) of 0.58 mg/kg/day in males and 0.72
mg/kg/day in females (expressed as diquat cation).
    2. A 1-year feeding study in dogs resulted in a systemic LOEL of
2.5 mg/kg/day and a systemic NOEL of 0.5 mg/kg/day in both sexes
(expressed as diquat cation).
    3. A 2-year feeding study in mice resulted in a systemic LOEL of
11.96 mg/kg/day in males and 16.03 mg/kg/day in females (expressed as
diquat cation), and a systemic NOEL of 3.56 mg/kg/day in males and 4.78
mg/kg/day in females (expressed as diquat cation).
    4. A developmental toxicity study in rats resulted in a maternal
toxicity LOEL of 32 to 56 mg/kg/day and a maternal toxicity NOEL of 8
to 14 mg/kg/day (expressed as diquat cation), and a developmental
toxicity LOEL of 32 to 56 mg/kg/day and a developmental toxicity NOEL
of 8 to 14 mg/kg/day (expressed as diquat cation).
    5. A developmental toxicity study in rabbits resulted in a maternal
toxicity LOEL of 5.0 mg/kg/day and a maternal toxicity NOEL of 2.5 mg/
kg/day (expressed as diquat cation). The developmental toxicity was not
clearly established.
    6. A recently submitted developmental toxicity study in rabbits
resulted in a maternal toxicity LOEL of 3 mg/kg/day and a maternal
toxicity NOEL of 1 mg/kg/day (expressed as diquat cation), and a
developmental toxicity LOEL of 10 mg/kg/day and a developmental
toxicity NOEL of 3 mg/kg/day (expressed as diquat cation).
    7. A developmental toxicity study in mice resulted in a maternal
toxicity LOEL of 2 mg/kg/day and a maternal toxicity NOEL of 1 mg/kg/
day (expressed as diquat cation), and a developmental toxicity LOEL of
4 mg/kg/day and a developmental toxicity NOEL of 2 mg/kg/day (expressed
as diquat cation).
    8. A two-generation reproduction study on rats resulted in a
systemic toxicity LOEL of 4 mg/kg/day and a systemic toxicity NOEL of
0.8 mg/kg/day (expressed as diquat cation), and a reproductive toxicity
LOEL of 12 to 20 mg/kg/day and a reproductive toxicity NOEL of 4 mg/kg/
day (expressed as diquat cation).
    9. Diquat showed nonmutagenicity in one gene mutation test (Ames),
two structural chromosome aberration tests (mouse micronucleus and
dominant lethal in mice), and one test for other genotoxic effects
(unscheduled DNA synthesis in rat hepatocytes in vitro). Positive
results were seen in one gene mutation test (mouse lymphoma cell assay)
and in one chromosome aberration test (human blood lymphocytes,
depending on the concentration of diquat and the presence of the
metabolic activation system).
    10. Metabolism studies showed about 90% of the administered dose
being eliminated in feces, indicating that diquat was poorly absorbed
from the gastrointestinal tract. Following a subcutaneous injection to
circumvent the intestine, nearly all of the administered dose was
recovered in the urine within 2 days.
    The Office of Pesticide Program's Health Effects Division's
Carcinogenicity Peer Review Committee (CPRC) has classified diquat as a
Group E carcinogen (no evidence of carcinogenicity) under the Agency's
Guidelines for Carcinogen Risk Assessment, published in the Federal
Register of September 24, 1986 (51 FR 33992). In its evaluation, CPRC
gave consideration to body weight changes in a 2-year feeding study in
mice and histopathological changes in the eyes in a 2-year chronic
feeding/carcinogenicity study in rats.
    The Reference Dose (RfD) is established at 0.005 mg/kg/day, based
on a NOEL of 0.5 mg/kg/day from the chronic toxicity study in dogs and
an uncertainty factor of 100. The Anticipated Residue Concentration
(ARC) from the current actions is estimated at 0.00074 mg/kg/day of
body weight/day for the general population and utilizes 15% of the RfD
for the U.S. population. The ARC for the most exposed subgroup is
0.0024 mg/kg/day of body weight/day for nonnursing infants (less than
1-year old) and utilizes 48% of the RfD. Therefore, no appreciable risk
is expected from the chronic dietary intake since the RfD is not
exceeded for either the general population or any subgroup.
    The nature of the residue is adequately understood for the purposes
of the tolerances. An adequate analytical method, extraction with
sulfuric acid with spectrometric detection, is available for
enforcement purposes. The analytical method for enforcing these
tolerances have been published in the Pesticide Analytical Manual, Vol.
II (PAM II).
    The pesticide is considered useful for the purposes for which it is
sought, and the tolerances are capable of achieving the intended
physical or technical effect. There are currently no actions pending
against the registration of this chemical.
    Based on the information and data considered, the Agency concludes
that the proposed tolerances will protect the public health. Therefore,
it is proposed that the tolerances 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 the ingredient
listed herein, may request within 30 days after the publication of this
document in the Federal Register that this proposal be referred to an
Advisory Committee in accordance with section 408(e) of the FFDCA.
    Interested persons are invited to submit written comments on the
proposed regulation. Comments must bear a notation indicating the
document control number, (PP 4E4365 and 4E4376/P645). All written
comments filed in response to this petition will be available in the
Public Response and Program Resources Branch at the above address from
8 a.m. to 4:30 p.m., Monday through Friday, except legal holidays.
    A record has been established for this proposal under docket number
(PP 4E4365 and 4E4376/P645) (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:
                    opp-docket@epamail.epa.gov
    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 proposal, 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, October 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 proposed 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
    Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.

    Dated: March 20, 1996.

Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.

    Therefore, it is proposed that 40 CFR part 180 be amended as
follows:

PART 180--[AMENDED]
    1. The authority citation for part 180 continues to read as
follows:
    Authority: 21 U.S.C. 346a and 371.
    2. In Sec. 180.226, by adding new paragraph (c) to read as follows:
Sec. 180.226   Diquat; tolerances for residues.
    *    *    *    *    *
    (c) Tolerances are established for the plant growth regulator
diquat [6,7-dihydrodipyrido (1,2-a:2',1'-c) pyrazinediium] derived from
application of the dibromide salt and calculated as the cation in or on
the following raw agricultural commodities:

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                      Commodity                        Parts per million
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Bananas..............................................        0.05
Coffee...............................................        0.05
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There are no U.S. registrations as of December 6, 1995.