Sethoxydim (CASRN 74051-80-2)
view QuickView

0190
Sethoxydim;
CASRN 74051-80-2
Health assessment information on a chemical substance is included in IRIS
only after a comprehensive review of chronic toxicity data by U.S. EPA
health scientists from several Program Offices and the Office of Research
and Development. The summaries presented in Sections I and II represent
a consensus reached in the review process. Background information and
explanations of the methods used to derive the values given in IRIS are
provided in the Background Documents.
STATUS OF DATA FOR Sethoxydim
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 11/01/1989 |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | no data |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Sethoxydim
CASRN — 74051-80-2
Last Revised — 11/01/1989
The oral Reference Dose (RfD) is based on the assumption that thresholds
exist for certain toxic effects such as cellular necrosis. It is expressed
in units of mg/kg-day. In general, the RfD is an estimate (with uncertainty
spanning perhaps an order of magnitude) of a daily exposure to the human
population (including sensitive subgroups) that is likely to be without
an appreciable risk of deleterious effects during a lifetime. Please refer
to the Background Document for an elaboration of these concepts. RfDs
can also be derived for the noncarcinogenic health effects of substances
that are also carcinogens. Therefore, it is essential to refer to other
sources of information concerning the carcinogenicity of this substance.
If the U.S. EPA has evaluated this substance for potential human carcinogenicity,
a summary of that evaluation will be contained in Section II of this file.
__I.A.1. Oral RfD Summary
Critical Effect |
Experimental Doses* |
UF |
MF |
RfD |
---|---|---|---|---|
Mild anemia in 1-Year Dog Study BASF Corporation, |
NOEL: 8.86/9.41 mg/kg/day LEL: 17.5/19.9 mg/kg/day |
100
|
1
|
9E-2
mg/kg/day |
*Conversion Factors -- Actual dose tested.
__I.A.2. Principal and Supporting Studies (Oral RfD)
BASF Corporation Chemicals Division. 1984. MRID No. 00152669. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Groups of 6 male and 6 female beagle dogs were orally dosed with NP-55 (96.86% pure technical sethoxydim) in their feed at concentrations of 0 (vehicle control), 300, 600, and 3600 ppm. The measued male/female doses were 0, 8.86/9.41, 17.5/19.9, and 110/129 mg/kg/day). The dogs were observed twice daily for clinical signs and weekly for body weight changes and food consumption. Water consumption was measured during weeks 12, 25, 39, and 51. Ophthalmologic examinations were conducted pretest, and at 6 and 12 months. Urine and jugular blood were collected from fasted dogs at study initiation, and at 1, 2, 3, 4, 5, 6, and 12 months. All dogs were examined grossly and their tissues were evaluated histopathologically.
No dogs died during this study, and no-compound related neoplastic lesions were found. The target organs were bone marrow and the liver. The NOEL for this study is 300 ppm (8.86/9.41 mg/kg/day, M/F). The LEL is 600 ppm (17.5/19.9 mg/kg/day, M/F) based upon mild anemia observed in males.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 100 was used to account for the inter- and intraspecies differences.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD
1) 1-Year Feeding - dog: Principal study - see previous description;
2) 2-Year Feeding (oncogenic) - rat: NOEL=360 ppm (18 mg/kg/day) (HDT); LEL=none; core grade guideline (BASF, 1981a)
3) 2-Generation Reproduction - rat: Systemic NOEL=360 ppm (18 mg/kg/day); Systemic LEL=1080 ppm (162 mg/kg/day) (decreased body weight gain, increased male thyroid and female adrenal weights); Reproductive NOEL=1080/3240 ppm (54/162 mg/kg/day); Reproductive LEL=none; core grade guideline (BASF, 1980a)
4) Teratology - rat: Maternal NOEL=40 mg/kg/day; Maternal LEL=100 mg/kg/day (significantly reduced adrenal weights); Developmental NOEL=250 mg/kg/day (HDT); Developmental LEL=none; core grade guideline (BASF, 1980b)
5) Teratology - rabbit: Maternal NOEL=160 mg/kg/day; Maternal LEL=480 mg/kg/day (severe weight loss, 5/16 deaths, 6/16 abortions, reduction in number of litters and viable fetuses); Developmental NOEL=160 mg/kg/day; Developmental LEL=480 mg/kg/day (increased number of random effects including skeletal and visceral abnormalities, reduced fetal weight and severe maternal toxicity); core grade guideline (BASF, 1980c)
Other Data Reviewed:
1) 2-Year Feeding (oncogenic) - mouse: Systemic NOEL=120 ppm (18 mg/kg/day); Systemic LEL=360 ppm (54 mg/kg/day) (non-neoplastic liver lesions); core grade guideline (BASF, 1981b)
2) 6-Month Feeding - dog: NOEL=600 ppm (20 mg/kg/day); LEL=6000 ppm (177/223 mg/kg/day) (liver effects and nonspecific anemia); core grade guideline (Nippon Soda Co., Ltd., 1981)
Data Gap(s): None
__I.A.5. Confidence in the Oral RfD
Study — High
Database — High
RfD — High
The critical study is of good quality and is given a high confidence rating. Additional studies are also of good quality; therefore the database is given a high confidence rating. High confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Files
Agency Work Group Review — 09/02/1986, 10/28/1986, 06/15/1989
Verification Date — 06/15/1989
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the RfD for sethoxydim conducted in August 2003 did not identify any critical new studies. IRIS users who know of important new studies may provide that information to the IRIS Hotline at hotline.iris@epa.gov or 202-566-1676.
__I.A.7. EPA Contacts (Oral RfD)
Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).
_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Sethoxydim
CASRN — 74051-80-2
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Sethoxydim
CASRN — 74051-80-2
This substance/agent has not undergone a complete evaluation and determination under US EPA's IRIS program for evidence of human carcinogenic potential.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Sethoxydim
CASRN — 74051-80-2
Last Revised — 11/01/1989
_VI.A. Oral RfD References
BASF Corporation Chemicals Division. 1984. MRID No. 00152669. Available from EPA. Write to FOI, EPA, Washington DC 20460.
BASF Wyandotte Corporation. 1980a. MRID No. 00045867. Available from EPA. Write to FOI, EPA, Washington DC 20460.
BASF Wyandotte Corporation. 1980b. MRID No. 00045863. Available from EPA. Write to FOI, EPA, Washington DC 20460.
BASF Wyandotte Corporation. 1980c. MRID No. 00045864. Available from EPA. Write to FOI, EPA, Washington DC 20460.
BASF Wyandotte Corporation. 1981a. MRID No. 00100526. Available from EPA. Write to FOI, EPA, Washington DC 20460.
BASF Wyandotte Corporation. 1981b. MRID No. 00100527. Available from EPA. Write to FOI, EPA, Washington DC 20460.
Nippon Soda Company, Ltd. 1981. Accession No. 099996. Available from EPA. Write to FOI, EPA, Washington DC 20460.
_VI.B. Inhalation RfD References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Sethoxydim
CASRN — 74051-80-2
Date |
Section |
Description |
---|---|---|
03/01/1988 | I.A.5. | Confidence levels revised |
07/01/1989 | I.A. | Withdrawn; new Oral RfD verified (in preparation) |
11/01/1989 | I.A. | Oral RfD summary replaced; RfD changed |
11/01/1989 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory Action section on-line |
04/01/1997 | III., IV., V. | Drinking Water Health Advisories, EPA Regulatory Actions, and Supplementary Data were removed from IRIS on or before April 1997. IRIS users were directed to the appropriate EPA Program Offices for this information. |
10/28/2003 | I.A.6 | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Sethoxydim
CASRN — 74051-80-2
Last Revised — 03/31/1987
- 74051-80-2
- BAS 9052
- 2-CYCLOHEXEN-1-ONE, 2-(1-(ETHOXYIMINO)BUTYL)-5-(2-(ETHYLTHIO)PROPYL)-3-HYDROXY-
- CYETHOXYDIM
- 2-(1-(ETHOXYIMINO)BUTYL)-5-(2-(ETHYLTHIO)PROPYL)-3-HYDROXY-2-CYCLOHEXEN-1-ONE
- NABU
- NP 55
- POAST
- Sethoxydim