Oxamyl (CASRN 23135-22-0)
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0181
Oxamyl ;
CASRN 23135-22-0
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 Oxamyl
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 03/01/1991 |
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 — Oxamyl
CASRN — 23135-22-0
Last Revised — 03/01/1991
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 |
---|---|---|---|---|
Decreased body weight 2-Year Rat Feeding/ du Pont, 1972a |
NOEL: 50 ppm LEL: 100 ppm |
100
|
1
|
2.5E-2
mg/kg/day |
*Conversion Factors: 1 ppm = 0.05 mg/kg/day (assumed rat food consumption)
__I.A.2. Principal and Supporting Studies (Oral RfD)
E.I. du Pont de Nemours and Company. 1972a. MRID No. 00083352, 00113400.
Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Four hundred twenty albino rats (55/sex/dose) were fed 0, 50, 100 and 150 ppm
oxamyl in their diets for 2 years. At 100 and 150 ppm, there was a decreased
rate of body weight gain. Cholinesterase depression was observed in the males
at 150 ppm after 8 days, but returned to normal by 1 month. No clinical signs
of toxicity were observed at 150 ppm.
__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. Although significant data gaps exist (studies must
be repeated), an additional UF was not considered necessary since existing
information on oxamyl indicates that the toxicological endpoint(s) will not be
affected by repeating the studies.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
The Registration Standard is scheduled to be completed by April of 1987.
Data Considered for Establishing the RfD:
1) 2-Year Feeding (oncogenic) - rat: Principal study - see previous
description; core grade supplementary
2) 2-Year Feeding - dog: NOEL=100 ppm (2.5 mg/kg/day); LEL=150 ppm (3.75
mg/kg/day) (liver effects); core grade supplementary (MTD not reached) (du
Pont, 1972b)
3) 3-Generation Reproduction - rat: Fetotoxic NOEL=50 ppm (2.5 mg/kg/day);
Fetotoxic LEL=100 ppm (5 mg/kg/day) (decreased weanling body weight); core
grade supplementary (summary data missing) (du Pont, 1971a)
4) Teratology - rat: Maternal NOEL=50 ppm (2.5 mg/kg/day); Maternal LEL=100
ppm (5 mg/kg/day) (decreased food consumption and body weight); core grade
supplementary (du Pont, 1971b)
5) Teratology - rabbit: Fetotoxic NOEL=4 mg/kg; core grade minimum (du Pont,
19780)
Data Gap(s): Chronic Rat Feeding Study; Chronic Dog Feeding Study; Rat
Reproductive Study; Rat Teratology Study
__I.A.5. Confidence in the Oral RfD
Study — Low
Database — Medium
RfD — Medium
The critical study was of inadequate quality and is given a low confidence rating. Other studies in the database are supportive; confidence in the data base can be considered medium to low. Confidence in the RfD can also be considered medium to low.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Files
Agency Work Group Review — 12/09/1986
Verification Date — 12/09/1986
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 oxamyl conducted in August 2003 identified one or more significant new studies. IRIS users may request the references for those studies from 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 — Oxamyl
CASRN — 23135-22-0
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Oxamyl
CASRN — 23135-22-0
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 — Oxamyl
CASRN — 23135-22-0
Last Revised — 03/01/1991
_VI.A. Oral RfD References
E.I. du Pont de Nemours and Company. 1971a. MRID No. 00066912. Available
from EPA. Write to FOI, EPA, Washington, DC 20460.
E.I. du Pont de Nemours and Company. 1972b. MRID No. 00114400. Available
from EPA. Write to FOI, EPA, Washington, DC 20460.
E.I. du Pont de Nemours and Company. 1972a. MRID No. 00083352, 00113400.
Available from EPA. Write to FOI, EPA, Washington, DC 20460.
E.I. du Pont de Nemours and Company. 1972b. MRID No. 00083352, 00113400.
Available from EPA. Write to FOI, EPA, Washington, DC 20460.
E.I. du Pont de Nemours and Company. 1980. MRID No. 00063009. Available
from EPA. Write to FOI, EPA, Washington, DC 20460.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Oxamyl
CASRN — 23135-22-0
Date |
Section |
Description |
---|---|---|
03/01/1988 | I.A.5. | Confidence levels revised |
03/01/1988 | III.A. | Health Advisory added |
08/01/1990 | III.A.10 | Primary contact changed |
03/01/1991 | I.A.4. | Citations added |
03/01/1991 | 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 — Oxamyl
CASRN — 23135-22-0
Last Revised — 03/31/1987
- 23135-22-0
- D-1410
- 2-Dimethylamino-1-(Methylthio)Glyoxal O-Methylcarbamoylmonoxime
- DPX 1410
- Methyl 2-(Dimethylamino)-N- (((Methylamino)Carbonyl)Oxy)-2-Oxoethanimidothioate
- Methyl N',N'-Dimethyl-N-((Methylcarbamoyl)Oxy)-1-Thiooxamimidate
- Oxamimidic Acid, N',N'-Dimethyl-N-((Methylcarbamoyl)oxy)-1(Methylthio)
- Oxamyl
- S-Methyl 1-(Dimethylcarbamoyl)-N-(Methylcarbamoyl)Oxy)Thioformimidate
- Thioxamyl
- Vydate