[Federal Register Volume 59, Number 244 (Wednesday, December 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31339]

[[Page Unknown]]

[Federal Register: December 21, 1994]


40 CFR Part 180

[PP 5F3188/P596; FRL-4924-4]
RIN 2070-AC18


Pesticide Tolerances for Paraquat

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.


SUMMARY: This document proposes to establish tolerances for the 
dessicant, defoliant, and herbicide paraquat (1,1'-dimethyl-4,4'-
bipyridinium ion) derived from the application of either the bis(methyl 
sulfate) or dichloride salt (both calculated as the cation) in or on 
the raw agricultural commodities (RACs) rice grain and rice straw. 
Zeneca Agricultural Products requested the establishment of these 
maximum permissible residues of the herbicide.

DATES: Comments, identified by the document control number [PP 5F3188/
P596], must be received on or before January 20, 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 Highway, 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). 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 p.m., Monday through Friday, 
excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: By mail: Robert J. Taylor, Product 
Manager (PM 25), Registration Division (7505C), Office of Pesticide 
Programs, Environmental Protection Agency, 401 M St., SW., Washington, 
DC 20460. Office location and telephone number: Rm. 241, CM #2, 1921 
Jefferson Davis Hwy., Arlington, VA 22202, 703-05-800.

SUPPLEMENTARY INFORMATION: EPA issued a notice, published in the 
Federal Register of April 17, 1985 (50 FR 15219), which announced that 
Chevron Chemical Co., 540 Hensley St., Richmond, CA 94804, had 
submitted a pesticide petition (PP 5F3188), proposing to amend 40 CFR 
180.205 by establishing tolerances for residues of the herbicide 
paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) derived from the 
application of either the bis(methyl sulfate) or dichloride salt (both 
calculated as the cation) in or on rice grain and rice straw at 0.05 
part per million (ppm).
    There were no comments or requests for referral to an advisory 
committee received in response to the notice of filing.
    The chemical, paraquat, was sold to ICI Americas, 1800 Concord 
Pike, Wilmington, DE 19897, which later changed its name to Zeneca Ag 
Products. The petitioner subsequently amended the petition by 
submitting a revised Section F proposing to establish a tolerance for 
residues of paraquat on rice straw at 0.06 ppm. Because there is a 
potential increase in risk to humans from this revision and because it 
has been longer than 5 years since the original proposal, the 
tolerances of 0.05 ppm on rice grain and 0.06 ppm on rice straw are 
being proposed again for 30 days to allow for public comments.
    The data submitted in the petition and other relevant material have 
been evaluated. The pesticide is considered useful for the purpose for 
which the tolerance is sought. The toxicological data listed below were 
considered in support of these proposed tolerances.
    1. Several acute studies placing technical paraquat in Toxicity 
Category I.
    2. A 1-year feeding study with dogs fed dosages of 0, 0.45, 0.93, 
and 1.51 milligrams of paraquat cation/kilogram (mg/kg) of body weight 
(bwt) per day with a no-observed-effect level (NOEL) of 0.45 mg/kg/day 
based on increased severity and extent of chronic pneumonitis in both 
sexes, but especially in the males at 0.93 mg/kg/day.
    3. A 2-year chronic feeding/carcinogenicity study in mice fed 
dosages of 0, 1.87, 5.62, and 15/18.75 mg/kg/day, expressed as paraquat 
cation (the highest dose had to be increased from 15 mg/kg/day to 18.75 
mg/kg/day because no toxic signs appeared at 15 mg/kg/day), with no 
carcinogenic effects observed under the conditions of the study up to 
and including 15/18.75 mg/kg/day (the highest dose tested [HDT]) and a 
systemic NOEL of 11.87 mg/kg/day, based on renal tubular degeneration 
in males and weight loss and decreased food intake in females at 5.62 
    4. A 2-year chronic feeding/carcinogenicity study in rats fed 
dosages of 0, 1.25, 3.75, and 7.5 mg/kg/day expressed as the cation, 
with uncertain evidence of carcinogenicity (squamous cell carcinomas in 
the head region (ears, nasal cavity, oral cavity, and skin)) in males 
at 7.5 mg/kg/day (HDT) and an approximate systemic NOEL of 1.25 mg/kg/
day, based on increased incidence of opacities, cataracts, and 
nonneoplastic lung lesions (alveolar macrophages, epithelialization, 
and slight peribronchiolar lymphoid hyperplasia) at 3.75 mg/kg/day.
    5. A 2-year chronic feeding/carcinogenicity study in rats fed 
dosages of 0.25/30 (M/F), 1.26/1.50 (M/F), 4.15/5.12 (M/F) and 12.25/
15.29 (M/F) mg/kg/day expressed as paraquat dichloride, with no 
carcinogenic effects at 12.5/15.25 mg/kg/day (HDT) and a systemic NOEL 
of 4.15/5.12 mg/kg/day based on increased mortality in males and 
females, decreased erythrocytes, hemoglobin, and serum protein in males 
and females, decreased hematocrit, glucose and corpuscular 
cholinestrease activity in males, decreased leukocytes, albumin-to-
globulin ratio and alkaline phosphatase, GOT and GDT activities in 
females, increased polymorphonucleocytes in males, increased potassium 
and glucose in females, decreased absolute and/or relative weights of 
heart (males and females) and liver and brain (females), and increased 
absolute weights of kidneys (males and females) and ovaries at 12.5/
15.25 mg/kg/day (HDT).
    6. A three-generation reproduction study with rats fed dosages of 
0, 1.25, 3.75, and 7.5 mg/kg/day, expressed as cation, with no 
reproductive effects observed at 7.5 mg/kg/day (HDT) and a systemic 
NOEL of 1.25 mg/kg/day based on increased incidence of alveolar 
histiocytosis in the lungs of the male and female parents at 3.75 mg/
    7. A developmental toxicity study in mice fed dosages of 0, 1.0, 
5.0, and 10 mg/kg/day, expressed as cation, with no teratogenic effects 
observed occurring at dosages up to and including 10 mg/kg/day (HDT); a 
fetotoxic NOEL of 5 mg/kg/day based on partially ossified sternebrae at 
10 mg/kg/day; and a maternal toxicity NOEL of 1.0 mg/kg/day based on 
weight reduction at 5.0 mg/kg/day.
    8. A developmental toxicity study in rats fed dosages of 0, 1.0, 
5.0, and 10.0 mg/kg/day, expressed at cation with no teratogenic 
effects observed at 10 mg/kg; a fetotoxic NOEL of 1.0 mg/kg/day based 
on reductions in weight and slight retardation in ossification at 5 mg/
kg/day; and maternal toxicity NOEL of 1.0 mg/kg/day based on 
piloerection, weight loss, and hunched appearance at 5.0 mg/kg/day.
    9. Sixteen acceptable mutagenic studies were submitted for 
paraquat. These include six gene mutation assays with S. typhimurium 
(T4 92, TA 98, TA 100, TA 1535, TA 1537, and TA 1538 and G-6 histidine-
requiring strains) and A. nidulans (strains 35 and P3); and L5178Y 
mouse lymphoma cells in culture; four structural chromosome aberration 
assays including dominant-lethal assays with Charles River CD- mice and 
Swiss-Webster mice; cytogenic assays (human lyphocytes and bone marrow 
of Wistar rats); and micronucleus test in mice; Six DNA damage/repair 
assays including S. typhimurium (TA 1978 and TA 1538 strains), 
Saccaromyces cerervisiae (D4, JD1, and ``other'' strains); human embryo 
epithelial cells; rat hepatocytes in culture; and sister chromatid 
exchange in Chinese hamster lung fibroblasts. Paraquat was negative in 
eight studies (mostly in gene mutation and chromosomal aberration 
assays); weakly positive in two gene mutation assays, one chromosomal 
aberration assay, and one DNA damage/repair assay; and positive in four 
DNA damage/repair assays.
    The reference dose (RfD) based on the 1-year feeding study in dogs 
(NOEL of 0.45 mg/kg/ bwt/day) and an uncertainty factor of 100 is 
calculated to be 0.0045 mg/kg/ bwt/day. The theoretical maximum residue 
contribution (TMRC) for published tolerances is 1.9 X 103 mg/kg 
bwt/day representing 42% of the RfD. The current action will utilize an 
additional 2% of the RfD. These tolerances and the previously 
established tolerances utilize a total of 43% of the RfD for the total 
U.S. population. For the most highly exposed U.S. subroup population, 
children 1 to 6 years of age, the current action and previously 
established tolerances utilize 96% of the RfD assuming that residue 
levels are at tolerance levels and 100% of the crop is treated.
    There are no desirable data lacking for this chemical. There are 
currently no actions pending against the continued registration of this 
pesticide. The Agency (Peer Review Committee) initially classified 
paraquat as a ``C'' carcinogen based on the significant increase in 
squamous cell carcinomas in the head region (ears, nasal cavity, oral 
cavity, and skin) of the high-dose (7.5 mg/kg/day male, Fischer rats) 
in the chronic feeding/carcinogenicity study. Review of the study by an 
independent laboratory concluded that the above tumor sites should not 
be combined. Without the combination, there were no statistically 
significant tumor increases for any particular tumor type. The Agency 
also considered two additional carcinogenicity studies (rat and mouse) 
and further evaluated the tumors.
    Based on a second peer review of paraquat, the Peer Review 
Committee, after reviewing all the evidence, concluded that there was 
no evidence of carcinogenicity in male Wistar rats at 12 mg/kg/day 
(HDT); in female Wistar rats at 15 mg/kg/day (HDT); in male and female 
JCL:ICR mice at 13 mg/kg/day (HDT); in male and female mice (SPF Swiss) 
derived at 19 mg/kg/day (HDT). It was also concluded that there was no 
evidence of carcinogenicity in male Fischer 344 rats at 7.5 mg/kg/day 
(HDT). According to the EPA Carcinogenicity Guidelines, paraquat was, 
therefore, placed in Category E (evidence of non-carcinogenicity for 
humans), based on a lack of convincing evidence of carcinogenicity in 
adequate studies with two animal species, rat and mouse.
    The pesticide is useful for the purposes for which these tolerances 
are sought. The nature of the residue in plants and animals is 
adequately understood for the purpose of establishing these tolerances. 
Adequate analytical methodology (reflux extraction with sulfuric acid), 
cleanup on ion-exchange resin, reduction with sodium dithionite color 
reagent and spectrophotometric color measurement) is available for 
enforcement purposes. The method is listed in the Pesticide Analytical 
Manual II (PAM II). Any secondary residue occurring in meat, milk, 
poultry, and eggs will be covered by existing tolerances on these 
    Based on the information considered by the Agency, the Agency has 
determined that when used in accordance with good agricultural 
practice, this ingredient is useful and that the tolerances established 
by amending 40 CFR part 180 would protect the public health. It is 
proposed, therefore, that the tolerances be established as set forth 
    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.
    Interested persons are invited to submit written comments on the 
proposed regulation. Comments must bear a notation indicating the 
document control number [PP 5F3188/P596]. 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 
p.m., Monday through Friday, except legal holidays.
    The Office of Management and Budget has exempted this rule from the 
requirements of section 3 of Executive Order 12866. Pursuant to the 
requirements of the Regulatory Flexibility Act (Pub. L. 96-54, 94 Stat. 
1164, 5 U.S.C. 601-12), the Administrator has determined that 
regulations establishing new tolerances or food additive regulations or 
establishing exemptions from tolerance requirements do not have a 
significant 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: December 1, 1994.

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. 180.205(a), by adding and alphabetically inserting 
entries for the following raw agricultural commodities (RACs), to read 
as follows:

Sec. 180.205   Paraquat; tolerances for residues.

    (a) *  *  *

                                                              Parts per 
                         Commodity                             million  
Rice grain.................................................         0.05
Rice straw.................................................         0.06

* * * * *

[FR Doc. 94-31339 Filed 12-20-94; 8:45 am]