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carbon disulfide Pesticide Tolerance Petition Filing 2/97

[Federal Register: February 12, 1997 (Volume 62, Number 29)] [Notices]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-704; FRL-5586-5]

Entek; Pesticide Tolerance Petition Filing 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Notice of filing.
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SUMMARY: This notice announces the initial filing of a pesticide petition 
proposing the establishment of tolerances for residues of carbon disulfide in 
or on almond nutmeats, almond hulls, peaches and plums (fresh prunes). This 
notice includes a summary of the petition that was prepared by the petitioner, 
Entek Corporation. 

DATES: Comments, identified by the docket number [PF-704], must be received on 
or before, March 14, 1997.

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. 

Comments and data may also be submitted electronically be 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 docket number [PF-704]. Electronic comments on this 
notice may be filed online at many Federal Depository Libraries. Additional 
information on electronic submissions can be found in Unit II. of this 
document. 

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). 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 8:30 a.m. to 4 p.m., Monday through Friday, 
excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Cynthia Giles-Parker, Product Manager (22), 
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. 229, CM #2, 1921 Jefferson Davis 
Highway, Arlington, VA, 703-305-5540, e-mail: giles-
parker.cynthia@epamail.epa.gov.

SUPPLEMENTARY INFORMATION: EPA has received a pesticide petition (PP 5F4482) 
from Entek Corporation, P.O. Box 458, Brea, CA 92822, proposing pursuant to 
section 408(d) of the Federal Food, Drug and Cosmetic Act (FFDCA), 21 U.S.C. 
346a(d), to amend 40 CFR 180.467 by establishing a tolerance, at 0.1 part per 
million (ppm), for residues of the fumigant carbon disulfide resulting from 
the soil application of sodium tetrathiocarbonate in or on the raw 
agricultural commodities almond nutmeats, almond hulls, peaches and plumes 
(fresh prunes). The proposed analytical method is gas chromatography using a 
sulfur specific detector. EPA has determined that the petition contains data 
or information regarding the elements set forth in section 408(d)(2); however, 
EPA has not fully evaluated the sufficiency of the submitted data at this time 
or whether the data supports granting of the petition. Additional data may be 
needed before EPA rules on the petition.

As required by section 408(d) of the FFDCA, as recently amended by the Food 
Quality Protection Act (Pub. L. 104-170), Entek Corporation included in the 
petition a summary of the petition and authorization for the summary to be 
published in the Federal Register in a notice of receipt of the petition. The 
summary represents the views of Entek Corporation. EPA is in the process of 
evaluating the petition. As required by section 408(d)(3) EPA is including the 
summary as a part of this notice of filing. EPA has made minor edits to the 
summary for the purpose of clarity.

I. Entek's Petition Summary

A. Residue Chemistry

1. Plant metabolism. Radiolabel metabolism studies, using 14C labeled sodium 
tetrathiocarbonate, were conducted with potatoes and tomatoes. The studies 
established that sodium tetrathiocarbonate rapidly degrades in soil and plants 
and the resulting residues are carbon disulfide (CS2), free and bound. No 
other residues of concern were identified in the radiolabel or other residue 
chemistry studies submitted by the petitioner.

2. Analytical method. An adequate analytical method for detecting free and 
bound CS2 residues in plants is available. The method has been validated by 
EPA. In brief, plant material is blended with water in a sealed container. 
Aliquots of the gas and liquid phases are removed and the free CS2 content is 
determined by purge-and-trap gas chromatography using a sulfur-specific 
detector. A sample of the liquid phase, purged for free CS2, is subjected to 
hot acid hydrolysis followed by purge-and-trap gas chromatography in order to 
measure the bound CS2 content. In general, the limit of detection for the 
analytical method is 0.5 ppb and the limit of quantitation is 1.7 parts per 
billion (ppb).

3. Magnitude of residues. Two field trials were conducted for each crop 
(peaches, plums and almonds). Trials were all conducted in California since it 
is the predominant growing area for each of the requested raw agricultural 
commodities (RACs) and the petitioner has proposed to limit use of 
Enzone<Register> (the product containing sodium tetrathiocarbonate) to 
Arizona, California, Oregon, and Washington. In each trial, sodium 
tetrathiocarbonate was applied in amounts equal to or greater than the maximum 
label rate and pretreatment, control and treatment samples were analyzed for 
free and bound CS2.

In the plum and peach trials, very low levels (<20 ppb) of free and bound CS2 
were observed in pretreated, control and treatment samples. In both almond 
trials, very low levels of free or bound CS2 (< 10 ppb) were observed in 
almond nutmeats. In one of the almond trials, unusually high levels of bound 
CS2 (from 567-6,761 ppb) were observed in control and treated almond hull 
samples. The petitioner believes that these atypical levels were most likely 
due to high natural occurrence or drift of an ethylene bisdithiocarbamate 
(EBDC) pesticide from a nearby source. 

Rigorous statistical analysis of the sample data clearly showed that there is 
no increase in CS2 (free or bound) above background levels for treated almond, 
pear or plum trees when compared to untreated or control trees.

B. Toxicological Profile

1. Acute toxicity. Technical sodium tetrathiocarbonate (32% active ingredient) 
is moderately toxic by the oral route, with a combined acute oral LD50 of 631 
milligrams/kilograms (mg/kg) in the rat. Technical sodium tetrathiocarbonate 
is practically nontoxic by dermal application (acute dermal LD50 > 2,000 
mg/kg) and slightly toxic after a 4-hour inhalation exposure (acute LC50 is 
4.73 mg/L (males) and 3.17 mg/L (females). Technical sodium tetrathiocarbonate 
is corrosive to skin and eyes but is not a dermal sensitizer. 

2. Genotoxicity. In the bacterial gene mutation test (Ames) technical sodium 
tetrathiocarbonate was negative, with or without metabolic activation. 
Technical sodium tetrathiocarbonate was also negative in a mammalian gene 
mutation assay (CHO/HGPRT), with or without metabolic activation. In the 
chromosome aberration assay, technical sodium tetrathiocarbonate gave a weakly 
positive result under activation conditions. Technical sodium 
tetrathiocarbonate was negative in the unscheduled DNA Synthesis assay. On the 
basis of the mutagenicity battery, Entek concludes that sodium 
tetrathiocarbonate is not mutagenic or genotoxic.

3. Developmental toxicity. Developmental toxicity studies with sodium 
tetrathiocarbonate were performed in the rat and rabbit. In the rat study, 
pregnant rats were administered sodium tetrathiocarbonate at doses of 0, 150, 
400, 450 and 500 mg/kg/day on gestation days 6 through 15. Necropsy 
examinations of the animals that died and animals that survived to final 
sacrifice did not reveal any lesions which could be attributed to sodium 
tetrathiocarbonate. Treatment with 150, 400 or 450 mg/kg/day of sodium 
tetrathiocarbonate did not alter fetal, skeletal or visceral development. The 
developmental toxicity no observed effect level (NOEL) for this study is 450 
mg/kg/day. In the rabbit study, pregnant rabbits were administered sodium 
tetrathiocarbonate at doses of 0, 75, 150 and 185 mg/kg/day on days 7-19 of 
gestation. Developmental effects (elevated resorptions and increased post- 
implantation loss) were observed at 185 mg/kg/day; developmental effects were 
not observed at the lower dose levels. The developmental toxicity no observed 
effect level (NOEL) for this study is 150 mg/kg/ day.

Entek has requested waivers for several of the toxicology studies that are 
normally required for crop tolerances. These include: 90-day oral toxicity 
study (rat and dog); 2-generation reproduction (rat); chronic toxicity study 
(rat and dog); oncogenicity (rat and mouse) and general metabolism. The basis 
for the waiver request is that the natural or background levels of CS2, either 
free or bound, are not increased from the application of sodium 
tetrathiocarbonate to almonds, peaches or plums.

In 1987, an oral reference dose (RfD) of 0.1 mg/kg/day for CS2 was established 
by EPA's Integrated Risk Information System (IRIS). 

C. Aggregate Exposure

1. Dietary exposure-- i. Food. Extensive residue data compiled by the 
petitioner and information in the public literature has shown a natural 
occurring dietary CS2 level (bound and free) of approximately 10-20 ppb. 
Assuming a dietary intake of 3,000 g/day, the daily intake of CS2 is 
approximately 0.06 mg/day. The use of sodium tetrathiocarbonate on almonds, 
peaches or plums is not anticipated to add to the daily intake of CS2 since, 
as noted above, no increases in CS2 residues above background levels were 
observed in the residue trials. It should also be noted that there was no 
increase above background CS2 levels for the crops (grapes and citrus) 
currently covered by a tolerance. 

ii. Drinking water. Two state-of-art prospective ground water monitoring 
studies were conducted for sodium tetrathiocarbonate. In both studies, sodium 
tetrathiocarbonate was applied above very shallow aquifers (3-7 ft. below the 
surface) and the ground water was analyzed for CS2. The studies demonstrated 
that CS2, from sodium tetrathiocarbonate application, is not a residual ground 
water contaminant.

2. Non-dietary exposure. Carbon disulfide is an industrial chemical used in 
the manufacture of rayon fibers; in the production of cellulose and rubber 
chemicals; as a solvent for cleaning and extraction; as an extractant for 
olive oil and in the production of adhesives. Accordingly, workers in these 
industries may be exposed to low levels of CS2 in the air. The daily exposure 
limit is 20 ppm (8-hr time weight average).

D. Cumulative Effects

There is no reliable information to indicate that carbon disulfide has a 
common mechanism of toxicity with any other chemical compound. 

E. Safety Determination

1. U.S. population. Since the use of sodium tetrathiocarbonate on almonds, 
peaches and plums is not anticipated to contribute to CS2 exposures, Entek 
concludes that there is a reasonable certainty that no harm will result from 
sodium tetrathiocarbonate application to these RACs.

2. Infants and children. Entek also concludes that there is a reasonable 
certainty that no harm will result to infants and children since no increase 
in infant or child exposure to CS2 will result from the application of sodium 
tetrathiocarbonate on almonds, peaches and plums.

F. International Tolerances

There are no Codex maximum residue levels [MRLs] established for residues of 
carbon disulfide resulting from the application of sodium tetrathiocarbonate.

II. Public Record

A record has been established for this notice under docket number [PF-704] 
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 8:30 a.m. to 4 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 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. 

List of Subjects

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

Dated: February 7, 1997.

Donald R. Stubbs,
Acting Director, Registration Division, Office of Pesticide Programs. 

[FR Doc. 97-3645 Filed 2-11-97; 8:45 am]