carbon disulfide Pesticide Tolerance Petition Filing 2/97
[Federal Register: February 12, 1997 (Volume 62, Number 29)] [Notices]
ENVIRONMENTAL PROTECTION AGENCY
Entek; Pesticide Tolerance Petition Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
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,
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: email@example.com. 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
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-
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
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
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: firstname.lastname@example.org
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]