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sethoxydim (Poast) Pesticide Tolerance Petition 1/97

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ENVIRONMENTAL PROTECTION AGENCY
[PF-688; FRL-5582-6]
Interregional Research Project Number 4; Pesticide Tolerance Petitions Filing
AGENCY: Environmental Protection Agency (EPA). 
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SUMMARY: This notice announces the filing of amendments to pesticide petitions 
0E3909, 2E4052, 2E4065, 2E4092, and 3E4162. These amendments propose to extend 
the effective date for time-limited tolerances established for the combined 
residues of the herbicide 2-[1- (ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-
hydroxy-2-cyclohexen-1- one (also referred to in this document as sethoxydim) 
and its metabolites in or on various raw agricultural commodities. This notice 
contains a summary of the amended petition prepared by BASF Corporation (BASF) 
and submitted by the Interregional Research Project Number 4 (IR-4), the 
petitioner.
DATES: Comments, identified by the docket number [PF-688; FRL-5582-6], must be 
received on or before February 7, 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 22202. Comments and data may also be submitted 
electronically by sending electronic mail (e- mail) to: opp-docket@epamail.epa.gov. Electronic comments on 
this notice may also be filed online at many Federal Depository Libraries. 
Information submitted as comments 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 4:00 p.m., Monday through Friday, 
excluding legal holidays.
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 PF-688. No 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 in Unit III of this document. 
FOR FURTHER INFORMATION CONTACT: By mail: Hoyt L. Jamerson, Registration 
Division (7505W), Office of Pesticide Programs, Environmental Protection 
Agency, 401 M St. SW., Washington, DC 20460. Office location and telephone 
number: Sixth Floor, Crystal Station #1, 2800 Jefferson Davis Highway, 
Arlington, VA 22202, (703) 308-8783, e- 

mail:jamerson.hoyt@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA has received amendments to pesticide petitions 
0E3909, 2E4052, 2E4065, 2E4092, and 3E4162 from the Interregional Research 
Project No. 4 (IR-4), New Jersey Agricultural Experiment Station, P.O. Box 
231, Rutgers University, New Brunswick, NJ 08903. These amendments propose, 
pursuant to section 408 of the Federal Food, Drug and Cosmetic Act (FFDCA), 21 
U.S.C. 346a, to amend 40 CFR part 180 by extending the effective date to 
expire on December 31, 1998, for time-limited tolerances established for 
residues of the herbicide 2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-
hydroxy-2- cyclohexen-1-one) and its metabolites containing the 2-cyclohexen-
1-one moiety (calculated as the herbicide) in or on asparagus at 4.0 parts per 
million (ppm), carrot at 1.0 ppm, cranberry and endive at 2.0 ppm, and 
peppermint and spearmint at 30 ppm. Registration for use of sethoxydim on 
endive is limited to Florida based on the geographical representation of the 
residue data submitted. Additional residue data will be required to expand the 
area of usage. Persons seeking geographically broader registration should 
contact the Agency's Registration Division at the address provided above. 
EPA has determined that the amendment 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. 
The nature of the residue is adequately understood, and practical and adequate 
analytical methods are available for enforcement purposes. Enforcement methods 
for sethoxydim are listed in the Pesticide Analytical Manual, Volume II (PAM 
II). Enforcement methods have also been submitted to the Food and Drug 
Administration for publication in PAM II.
As required by section 408(d) of the FFDCA, as recently amended by the Food 
Quality Protection Act, IR-4 submitted a summary of amendments to the 
pesticide petitions and authorization for the summary to be published in the 
Federal Register in a notice of receipt of the petition. The summary was 
prepared by and represents the views of BASF; EPA, as mentioned above, 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 may have made 
minor edits to the summary for the purpose of clarity.
I. Petition Summary
A. Toxicological Profile
1. Data summary. A summary of toxicological studies for sethoxydim follows:
     i. A 1-year feeding study with dogs fed diets containing 0, 8.86/ 9.41, 
17.5/19.9, and 110/129 milligrams (mg)/kilogram (kg)/day (males/ females) with 
a no-observed-effect-level (NOEL) of 8.86/9.41 mg/kg/day (males/females) based 
on equivocal anemia in male dogs at the 17.5-mg/ kg/day dose level.
     ii. A 2-year chronic feeding/carcinogenicity study with mice fed diets 
containing 0, 40, 120, 360, and 1,080 ppm (equivalent to 0, 6, 18, 54, and 162 
mg/kg/day) with a systemic NOEL of 120 ppm (18 mg/kg/ day) based on non-
neoplastic liver lesions in male mice at the 360 ppm (54 mg/kg/day) dose 
level. There were no carcinogenic effects observed under the conditions of the 
study. The maximum tolerated dose (MTD) was not achieved in female mice.
     iii. A 2-year chronic feeding/carcinogenic study with rats fed diets 
containing 0, 2, 6, and 18 mg/kg/day with a systemic NOEL greater than or 
equal to 18 mg/kg/day (highest dose tested). There were no carcinogenic 
effects observed under the conditions of the study. This study was reviewed 
under current guidelines and was found to be unacceptable because the doses 
used were insufficient to induce a toxic response and an MTD was not achieved.
     iv. A second chronic feeding/carcinogenic study with rats fed diets 
containing 0, 360, and 1,080 ppm (equivalent to 18.2/23.0, and 55.9/ 71.8 
mg/kg/day (males/females). The dose levels were too low to elicit a toxic 
response in the test animals and failed to achieve an MTD or define a lowest 
effect level (LEL). Slight decreases in body weight in rats at the 1,080-ppm 
dose level, although not biologically significant, support a free-standing no-
observed-adverse-effect-level (NOAEL) of 1,080 ppm (55.9/71.8 mg/kg/day 
(males/females)). There were no carcinogenic effects observed under the 
conditions of the study. 
     v. A developmental toxicity study in rats fed dosages of 0, 50, 180, 650, 
and 1,000 mg/kg/day with a maternal NOAEL of 180 mg/kg/day and a maternal LEL 
of 650 mg/kg/day (irregular gait, decreased activity, excessive salivation, 
and anogenital staining); and a developmental NOAEL of 180 mg/kg/day and a 
developmental LEL of 650 mg/ kg/day (21 to 22 percent decrease in fetal 
weights, filamentous tail, and lack of tail due to the absence of sacral 
and/or caudal vertebrae, and delayed ossification in the hyoids, vertebral 
centrum and/or transverse processes, sternebrae and/or metatarsals, and 
pubes). 
     vi. A developmental toxicity study in rabbits fed doses of 0, 80, 160, 
320, and 400 mg/kg/day with a maternal NOEL of 320 mg/kg/day and a maternal 
LOEL of 400 mg/kg/day (37 percent reduction in body weight gain without 
significant differences in group mean body weights and decreased food 
consumption during dosing); and a developmental NOEL greater than 400 
mg/kg/day (highest dose tested). 
     vii. A 2-generation reproduction study with rats fed diets containing 0, 
150, 600, and 3,000 ppm (approximately 0, 7.5, 30, and 150 mg/kg/day) with no 
reproductive effects observed under the conditions of the study.
     viii. Mutagenicity studies including: Ames assays were negative for gene 
mutation in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537, 
with and without metabolic activity; a Chinese hamster bone marrow cytogenetic 
assay was negative for structural chromosomal aberrations at doses up to 5,000 
mg/kg in Chinese hamster bone marrow cells in vivo; and recombinant assays and 
forward mutations tests in Bacillus subtilis, Escherichia coli, and S. 
typhimurium were all negative for genotoxic effects at concentrations of 
greater than or equal to 100 percent.
     ix. In a rat metabolism study, excretion was extremely rapid and tissue 
accumulation was negligible.
2. Chronic toxicity. Based on the available chronic toxicity data, EPA has 
established the Reference Dose (RfD) for sethoxydim at 0.09 milligrams 
(mg)/kilogram (kg) bw/day. The RfD for sethoxydim is based on a 1-year feeding 
study in dogs with a threshold no-observed effect level (NOEL) of 8.86 
mg/kg/day and an uncertainty factor of 100. 
3. Acute toxicity. Based on the available acute toxicity data, sethoxydim does 
not pose any acute dietary risks. Several acute toxicology studies place 
technical sethoxydim in acute toxicity category IV for primary eye and dermal 
irritation and acute toxicity category III for acute oral, dermal, and 
inhalation. The dermal sensitization-guinea pig study was waived because no 
sensitization was seen in guinea pigs dosed with the end-use product Poast (18 
percent active ingredient).
4. Carcinogenicity. These tolerances were established as time- limited 
tolerances since an acceptable carcinogenicity study is needed in one rodent 
species. A repeat chronic feeding/carcinogenicity study in rats was submitted 
to EPA in November of 1995 and is awaiting review. The Agency will reassess 
sethoxydim tolerances based on the outcome of the rat chronic 
feeding/carcinogenicity study and, if appropriate, will establish permanent 
tolerances for asparagus, carrot, cranberry, endive, peppermint and spearmint. 
In the interim, there is little risk from the proposed time extension for 
these uses of sethoxydim, since available studies in rats and mice indicate no 
carcinogenic effects, there are adequate data to establish a RfD, existing 
tolerances (including these time-limited tolerances) do not exceed the RfD, 
and the tolerances for asparagus, carrot, cranberry, endive, and mint utilize 
less than 1 percent of the Reference Dose. Thus a cancer risk assessment is 
not necessary. 
B. Aggregate Exposure
For purposes of assessing the potential dietary exposure, BASF has estimated 
aggregate exposure based on the Theoretical Maximum Residue Contribution 
(TMRC) from the tolerances of sethoxydim on: asparagus at 4.0 ppm, carrot at 
1.0 ppm, cranberry and endive at 2.0 ppm, and peppermint and spearmint at 30.0 
ppm. (The TMRC is a "worst case" estimate of dietary exposure since 
it is assumed that 100 percent of all crops for which tolerances are 
established are treated and that pesticide residues are at the tolerance 
levels.) The TMRC from existing tolerances for the overall U.S. population is 
estimated at 0.0311961 mg/kg bw/day, or 36 percent of the RfD. Dietary 
exposure to residues of sethoxydim in or on asparagus, carrot, cranberry, 
endive and mint increases the TMRC by 0.000701 mg/kg bw/day and accounts for 
less than 1 percent of the RfD for the overall U.S. population. EPA estimates 
indicate that dietary exposures will not exceed the RfD for any population 
subgroup for which EPA has data [See Proposed Rule at 60 FR 13941, March 15, 
1995]. This exposure assessment relies on very conservative assumptions--100 
percent of crops will contain sethoxydim residues and those residues would be 
at the level of the tolerance which results in an overestimate of human 
exposure. 
Other potential sources of exposure of the general population to residues of 
pesticides are residues in drinking water and exposure from non-occupational 
sources. Based on the available studies used in EPA's assessment of 
environmental risk, BASF does not anticipate exposure to residues of 
sethoxydim in drinking water. There is no established Maximum Concentration 
Level (MCL) for residues of sethoxydim in drinking water under the Safe 
Drinking Water Act (SDWA). 
EPA has not estimated non-occupational exposure for sethoxydim. Sethoxydim is 
labeled for use by homeowners on the following use sites: flowers, evergreens, 
shrubs, trees, fruits, vegetables, ornamental ground covers, and bedding 
plants. Hence, the potential for non- occupational exposure to the general 
population exists. However, these use sites do not appreciably increase 
exposure. Protective clothing requirements, including the use of gloves, 
adequately protect homeowners when applying the product. The product may only 
be applied through hose-end sprayers or tank sprayers as a 0.14% solution. 
Sethoxydim is not a volatile compound so inhalation exposure during and after 
application would be negligible. Dermal exposure would be minimal in light of 
the protective clothing and the low application rate. Post- treatment (re-
entry) exposure would be negligible for these use sites as contact with 
treated surfaces would be low. Dietary risks from treated food crops are 
already adequately regulated by the established tolerances. The additional 
uses endive, asparagus , carrots, cranberries, peppermint, and spearmint will 
not increase the non- occupational exposure appreciably, if at all. Thus, BASF 
believes that the potential for non-occupational exposure to the general 
population is insignificant.
BASF also considered the potential for cumulative effects of sethoxydim and 
other substances that have a common mechanism of toxicity. BASF is aware of 
one other active ingredient which is structurally similar, clethodim. However, 
BASF believes that consideration of a common mechanism of toxicity is not 
appropriate at this time. BASF does not have any reliable information to 
indicate that toxic effects produced by sethoxydim would be cumulative with 
clethodim or any other chemical; thus, BASF is considering only the potential 
risks of sethoxydim in its exposure assessment. 
C. Determination of Safety for U.S. Population 
Reference Dose (RfD). Using the conservative exposure assumptions described 
above, based on the completeness and the reliability of the toxicity data, EPA 
has estimated that aggregate exposure to sethoxydim will utilize 37 percent of 
the RfD for the U.S. population. EPA generally has no concern for exposures 
below 100 percent of the RfD. Therefore, based on the completeness and 
reliability of the toxicity data, and the conservative exposure assessment, 
BASF concludes that there is a reasonable certainty that no harm will result 
from aggregate exposure to residues of sethoxydim, including all anticipated 
dietary exposure and all other non-occupational exposures. 
D. Determination of Safety for Infants and Children 
1. Developmental toxicity. Developmental toxicity was observed in a 
developmental toxicity study using rats but was not seen in a developmental 
toxicity study using rabbits. A developmental NOAEL of 180 mg/kg/day and 
developmental LEL of 650 mg/kg/day were established for the rat study. Effects 
noted in the rat study included decrease in fetal weights (21 to 22 percent), 
filamentous tail, lack of tail (due to absence of sacral and/or caudal 
vertebrae), and delayed ossification (hyoids, vertebral centrum and/or 
transverse processes, sternebrae and/ or metatarsals, and pubes). The 
developmental NOEL for the rabbit study was greater than 400 mg/kg/day and was 
the highest dose tested. The developmental effects observed in the rat study 
are believed to be secondary effects resulting from maternal stress. 
2. Reproductive toxicity. A two-generation reproduction study with rats fed 
diets containing 0, 150, 600, and 3,000 ppm (approximately 0, 7.5, 30, and 150 
mg/kg/day) produced no reproductive effects during the course of the study. 
Although the dose levels were insufficient to elicit a toxic response, the 
Agency has considered this study usable for regulatory purposes and has 
established a free-standing NOEL of 3,000 ppm (approximately 150 mg/kg/day) 
[See Proposed Rule at 60 FR 13941, March 15, 1995].
RFD. Based on the demonstrated lack of significant developmental or 
reproductive toxicity BASF believes that the RfD used to assess safety to 
children should be the same as that for the general population, 0.09 
mg/kg/day. Using the conservative exposure assumptions described above, BASF 
has concluded that the most sensitive child population is that of children 
ages 1 to 6. BASF calculates the exposure to this group to be less than 70 
percent of the RfD for all uses (including those proposed in this document). 
The proposed tolerances in endive, asparagus, carrot, cranberry, peppermint 
and spearmint represent an exposure to this group of less than 1 percent. 
Based on the completeness and reliability of the toxicity data and the 
conservative exposure assessment, BASF concludes that there is a reasonable 
certainty that no harm will result to infants and children from aggregate 
exposure to the residues of sethoxydim, including dietary exposure and all 
other non- occupational exposures.
3. Endocrine effects. No special studies investigating potential estrogenic or 
endocrine effects of sethoxydim have been conducted. However, the standard 
battery of required studies has been completed. These studies include an 
evaluation of the potential effects on reproduction and development, and an 
evaluation of the pathology of the endocrine organs following repeated or 
long-term exposure. These studies are generally considered to be sufficient to 
detect any endocrine effects but no such effects were noted in any of the 
studies. 
II. Other Considerations
There is no reasonable expectation that secondary residues will occur in milk, 
eggs, or meat of livestock and poultry from the proposed uses of sethoxydim on 
asparagus, cranberries, endive, and mint; there are no livestock feed 
commodities associated with these commodities. Any secondary residues 
occurring in meat, fat, meat byproducts and milk of cattle, goats, hogs, 
horses and sheep from the proposed use on carrots will be covered by existing 
tolerances. There are no residues expected to occur in poultry byproducts, 
fat or eggs since carrots are not considered a poultry feed item. 
There are no Codex maximum residue levels established for residues of 
sethoxydim on asparagus, carrots, cranberry, endive, or mint. 
III. Public Record
EPA invites interested persons to submit comments on this notice of filing. 
Comments must bear a notation indicating the docket number, [PF-688; FRL-5582-
6]. 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 8:30 a.m. to 4:00 p.m., Monday through Friday, except legal 
holidays.
A record has been established for this rulemaking under docket number [PF-688; 
FRL-5582-6] (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 4:00 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 notice of filing, 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.
Authority: 21 U.S.C. 346a.
Dated: December 31, 1996.
Stephen L. Johnson, Director
Registration Division
Office of Pesticide Programs 
[FR Doc. 97-415 Filed 1-7-97; 8:45 am]
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