[Federal Register Volume 59, Number 163 (Wednesday, August 24, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-20813]


[[Page Unknown]]

[Federal Register: August 24, 1994]


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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180

[PP 2F4107/R2075; FRL094906092]
RIN 207009AB78

 

Difenoconazole; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is establishing tolerances for residues of the fungicide 
difenoconazole in or on certain raw agricultural commodities. Ciba-
Geigy Corp. requested this regulation to estalish the maximum 
permissible levels of residues of the fungicide in or on the 
commodities.

EFFECTIVE DATE: This regulation becomes effective August 24, 1994.

ADDRESSES: Written objections and hearing requests, identified by the 
document control number, [PP 2F4107/R2075], may be submitted to: 
Hearing Clerk (1900), Environmental Protection Agency, Rm. M3708, 401 M 
St., SW., Washington, DC 20460.
    A copy of any objections and hearing request filed with the Hearing 
Clerk should be identified by the document control number and submitted 
to: Public Response and Program Resources Branch, Field Operations 
Division (7506C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington DC 20450. In person, 
bring copy of objections and hearing request to: Rm. 1132, CM 1B2, 1921 
Jefferson Davis Hwy., Arlington, VA 22202. Fees accompanying objections 
shall be labeled ``Tolerance Petition Fees'' and forwarded to: EPA 
Headquarters Accounting Operations Branch, OPP (Tolerance Fees), P.O. 
Box 360277M, Pittsburgh, PA 15251.

FOR FURTHER INFORMATION CONTACT: By mail: Cynthia Giles-Parker, Product 
Manager (PM) 22, Registration Division, Environmental Protection 
Agency, 401 M St., SW., Washington, DC 20460. Office location and 
telephone number: Rm. 229, CM 1B2, 1921 Jefferson Davis Highway, 
Arlington, VA 22202, (703)-305-5540.

SUPPLEMENTARY INFORMATION: EPA issued a notice published in the Federal 
Register of June 10, 1992 (57 FR 24644), which announced that Ciba-
Geigy Corporation, P.O. Box 18300, Greensboro, NC 27419-8300, had 
submitted a pesticide tolerance petition (PP 2F4107) to EPA requesting 
that the Administrator, pursuant to sections 408(d) of Federal Food, 
Drug and Cosmetic Act, 21 U.S.C. 346a(d), establish a tolerance for the 
fungicide, difenoconazole, 1-(2-[4-(4-chlorophenoxy)-2-chlorophenyl]-4-
methyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole, in or on in or on 
wheat forage at 0.1 part per million (ppm), wheat straw at 0.1 ppm, 
barley forage at 0.1 ppm, and barley straw at 0.1 ppm. In the Federal 
Register of March 30, 1994 (59 FR 14854), EPA issued in the Federal 
Register a corrected filing of the notice published in the Federal 
Register of January 7, 1994 (59 FR 1017), which announced that Ciba-
Geigy Corp. had submitted an amendment to the petition, proposing to 
establish additional tolerances as follows: cattle, fat, meat, and 
meat-by-products (mbyp) at 0.05 ppm; eggs at 0.05 ppm; milk at 0.01 
ppm; goats, fat, meat, and mbyp at 0.05 ppm; hogs, fat, meat, and mbyp 
at 0.05 ppm; horses, fat, meat, and mbyp at 0.05 ppm; poultry, fat, 
meat, and mbyp at 0.05 ppm; sheep, fat, meat, and mbyp at 0.05 ppm; 
barley grain at 0.1 ppm; and wheat grain at 0.1 ppm. Ciba-Geigy 
subsequently amended the petition to withdraw without prejudice for 
future filings the tolerances for barley forage, barley straw and 
barley grain.
    The chemical name for difenoconazole is editorially corrected to 
read: [(2S,4R)/(2R,4S)]/[2R,4R/2S,4S)] 1-(2-[4-(4chlorophenoxy)-2-
chlorophenyl]-4-methyl-1,3-dioxolan-2-yl-methyl)1H-1,2,4-triazole.
    There were no comments or requests for referral to an advisory 
committee received in response to these notices of filing.
    The data submitted in the petitions and all other relevant material 
have been evaluated. The toxicology data considered in support of the 
tolerances include:
    1. A rat acute oral study with an LD50 of 1,453 milligrams 
(mg)/kilogram (kg).
    2. A 13-week rat feeding study with a no-observed-effect-level 
(NOEL) of 20 ppm (1 mg/kg/day).
    3. A 13-week mouse feeding study with a NOEL of 20 ppm.
    4. A 26-week dog feeding study with a NOEL of 1,000 ppm.
    5. A 21-day rabbit dermal study with a NOEL of 10 mg/kg and 
reduction in body weight gain and food consumption from exposure to 
doses equal or greater than 100 mg/kg.
    6. A carcinogenicity study in mice with a NOEL of 30 ppm and a 
Lowest Effect Level (LEL) of 300 ppm due to reductions in cumulative 
body weights. There was limited evidence of carcinogenicity based on 
the occurrence of increased benign and/or malignant liver tumors in 
males and females. The carcinogenic effects observed are discussed 
below.
    7. A rat chronic feeding/carcinogenicity study with a NOEL of 20 
ppm (1 mg/kg/day) for systemic effects and a LEL of 500 ppm (25 mg/kg/
day) due to reductions in cumulative body weight gains and 
hepatotoxicity in males. There was no evidence of carcinogenicity under 
conditions of the study.
    8. A 1-year dog chronic feeding study with a NOEL of 100 ppm and 
the LEL was 500 ppm due to reduction in food consumption and increase 
in alkaline phosphatase in males at high dose.
    9. A two-generation reproduction study in rats with a parental and 
reproductive NOEL of 25 ppm (1.25 mg/kg/day) and an LEL of 250 ppm 
(12.5 mg/kg/day) due to reduction of female body weight gain, and 
significant reductions in male pup weight at day 21.
    10. A developmental toxicity study in rabbits with a Maternal NOEL 
of 25 mg/kg and a LEL of 75 mg/kg/day due to decreased body weight, 
death of one doe and abortion, and a developmental NOEL of 25 mg/kg and 
a LEL of 75 mg/kg due to increased postimplantation loss and 
resorptions and significantly decreased fetal weight.
    11. A developmental toxicity study in rats with a maternal NOEL of 
16 mg/kg and a LEL = 85 mg/kg due to excess salivation, and decreased 
body weight gain and food consumption, and a developmental NOEL of 85 
mg/kg/day and an LEL of 171 mg/kg due to increase bifid or unilateral 
ossification of thoracic vertebrate, increased average number of 
ossified hyoid and decrease in average number of sternal centers of 
ossification.
    12. A Microbial Gene Mutation study and an Unscheduled DNA 
synthesis in rat hepatocyte study were both negative. An In vivo 
micronucleus assay / chromosomal analysis study showed no increase in 
micronucleated polychromatic erythrocytes at any dose tested.
    13. A rat metabolism study showed that difenoconazole was 
adequately absorbed and mainly eliminated via the bile. No evidence of 
bioaccumulation in any tissue was noted.
    The Health Effects Division Carcinogenicity Peer Review Committee 
has concluded that the available data provide limited evidence of the 
carcinogenicity of difenoconazole in mice and has classified 
Difenoconazole as a Group C (possible human carcinogen with limited 
evidence of carcinogenicity in animals) in accordance with Agency 
guidelines, published in the Federal Register in 1986 (51 FR 33992, 
Sept. 24, 1986) and recommended that for the determined that a 
quantitative risk assessment is not appropriate for the following 
reasons:
    1. The carcinogenic response observed with this chemical, 
statistically significant increases in hepatocellular adenomas, 
carcinomas and combined adenomas/carcinomas in both sexes of CD-1 mice, 
occurred only at doses considered to be excessively high for 
carcinogenicity testing.
    2. There were no apparent tumor increases in either sex in Sprague-
Dawley rats at dietary levels up to 2,500 ppm.
    3. Difenoconazole was not mutagenic in three well conducted 
genotoxic assays.
    Based on this evidence, EPA concludes that difenoconazole poses at 
most a negligible cancer risks to humans and that for purposes of risk 
characterization the Margin of Expsoure (MOE) approach should be use 
for quantification of human risk. In a spring wheat processing study, 
no residues were detected in grain or any processed fraction. 
Therefore, food/feed additive tolerances are not needed in conjunction 
with this use on wheat.
    Using a 100-fold safety factor and the NOEL of 1 mg/kg/day 
determined by the most sensitive species from the rat chronic feeding 
study, the Reference Dose (RfD) is 0.01 mg/kg/day. The theoretical 
maximum residue contribution (TMRC) from the established and proposed 
tolerances is 0.00041 mg/kg/day and utilizes 4 percent of the RfD for 
the overall U. S. population. For exposure of the most highly exposed 
subgroups in the population, children (1 to 6) and Nonnursing infants 
(less than 1), the TMRC is 0.000946 mg/kg/day and utilizes 9 percent of 
the RfD.
    The dietary acute exposure MOE for developmental toxicity effects 
was calculated to be 25,000 for high exposure in the females 13+ 
subgroup. For substances whose acute NOEL is based on animal studies, 
the Agency is not generally concerned unless the MOE is below 100.
    The metabolism of difenoconazole in plants is adequately 
understood. The tolerances established for milk, eggs, meat, fat, and 
meat by products will cover any dietary exposure from secondary 
residues in these RACs. Due to the following chemistry data gaps--
Stability of the Technical Grade Active Ingredient (TGAI) to Metal Ions 
Study [GLN 63-13], Storage Stability of Difenoconazole in other Raw 
Agricultural Commodities [GLN 1714(e)], and Additional Wheat Field 
Residue Trials [GLN 171-4(k)]--EPA believes it is inappropriate to 
establish permanent tolerance for the use of difenoconazole at this 
time. However, based on the (1) apparent storage stability, (2) 11 
acceptable field studies (15 to 20 field trials are required), and (3) 
apparent negligible residues of difenoconazole in wheat RACs, EPA 
believes that the existing data support a time-limited tolerance to 
December 31, 1998.
    An adequate analytical method, gas chromatography with nitrogen 
phosphorous detection, is available for enforcement purposes. Because 
of the long lead time from establishing these tolerances to publication 
of the enforcement methodology in the Pesticide Analytical Manual, Vol. 
II, the analytical methodology is being made available in the interim 
to anyone interested in pesticide enforcement when requested from: 
Calvin Furlow, Public Information Branch, Field Operations Division 
(7506C), Office of Pesticide Programs, Environmental Protection Agency, 
401 M St., SW., Washington, DC 20460. Office location and telephone 
number: Rm. 242, CM 1B2, 1921 Jefferson Davis Hwy., Arlington, VA 
22202, (703)-305-4432.
    The pesticide is considered useful for the purposes for which the 
tolerances are sought. Based on the information and data considered, 
the Agency concludes that the establishment of the time-limited 
tolerances will protect the public health. Therefore, the tolerances 
are established as set forth below.
    Any person adversely affected by this regulation may, within 30 
days after publication of this document in the Federal Register, file 
written objections and/or request a hearing with the Hearing Clerk, at 
the address given above (40 CFR 78.20). A copy of the objections and/or 
hearing requests filed with the Hearing Clerk should be submitted to 
the OPP docket for this rulemaking. The objections submitted must 
specify the provisions of the regulation deemed objectionable and the 
grounds for the objections (40 CFR 178.25). Each objection must be 
accompanied by the fees provided by 40 CFR 180.33(i). If a hearing is 
requested, the objections must include a statement of the factual 
issue(s) on which a hearing is requested, and the requestor's 
contentions on each such issue, and a summary of the evidence relied 
upon by the objection (40 CFR 178.27). A request for a hearing will be 
granted if the Administrator determines that the material submitted 
shows the following: there is a genuine and substantial issue of fact; 
there is a reasonable possibility that available evidence identified by 
the requestor would, if established, resolve on or more of such issues 
in favor of the requestor, taking into account uncontested claims or 
facts to the contrary; and resolution of the factual issue(s) in the 
manner sought by the requestor would be adequate to justify the action 
requested (40 CFR 178.32).
    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, Recording and 
recordkeeping requirements.

Dated: August 18, 1994.

Daniel M. Barolo,
Director, Office of Pesticide Programs.

    Therefore, 40 CFR part 180 is 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. By adding new Sec. 1180.475, to read as follows:


Sec. 1180.475   Difenoconazole; tolerances for residues.

    (a) Time-limited tolerances, to expire on December 31, 1998, are 
established for difenoconazole, [(2S,4R)/(2R,4S)]/[2R,4R/2S,4S)] 1-(2-
[4-(4-chlorophenoxy)-2-chlorophenyl]-4-methyl-1,3-dioxolan-2yl-methyl)-
1H-1,2,4-triazole, in or on the following raw agricultural commodities:

------------------------------------------------------------------------
                                                              Parts per 
                         Commodity                             million  
------------------------------------------------------------------------
Cattle, fat................................................         0.05
Cattle, meat...............................................         0.05
Cattle, mbyp...............................................         0.05
Eggs.......................................................         0.05
Goats, fat.................................................         0.05
Goats, meat................................................         0.05
Goats, mbyp................................................         0.05
Hogs, fat..................................................         0.05
Hogs, meat.................................................         0.05
Hogs, mbyp.................................................         0.05
Horses, fat................................................         0.05
Horses, meat...............................................         0.05
Horses, mbyp...............................................         0.05
Milk.......................................................         0.01
Poultry, fat...............................................         0.05
Poultry, meat..............................................         0.05
Poultry, mbyp..............................................         0.05
Sheep, fat.................................................         0.05
Sheep, meat................................................         0.05
Sheep, mbyp................................................         0.05
Wheat, forage..............................................          0.1
Wheat, grain...............................................          0.1
Wheat, straw...............................................          0.1
------------------------------------------------------------------------

    (b) Residues in these commodities not in excess of the established 
tolerance resulting from the use described in paragraph (a) of this 
section remaining after expiration of the time-limited tolerance will 
not be considered to be actionable if the fungicide is applied during 
the term of and in accordance with the provisions of the above 
regulation.

[FR Doc. 94-20813 Filed 8-23-94; 8:45 am]
BILLING CODE 6560-50-F