Disulfoton (CASRN 298-04-4)
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0154
Disulfoton;
CASRN 298-04-4
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 Disulfoton
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 03/01/1988 |
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 — Disulfoton
CASRN — 298-04-4
Last Revised — 03/01/1988
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
|
---|---|---|---|---|
ChE inhibition, optic 2-year Rat Study Mobay Chemical, 1985 |
NOEL: None LEL:0.8 ppm diet (0.04 mg/kg/day) |
1000
|
1
|
4E-5
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)
Mobay Chemical Company. 1985. MRID No. 00129456, 00146873, 41115401. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Disulfoton was fed to male and female Fischer 344 rats at 0.8, 3.3, or 13 ppm in the diet for 105 weeks (the intended concentrations were 1, 4, and 16 ppm). Dose-related inhibition of cholinesterase was observed for plasma, erythrocyte, and brain in both sexes in all treated groups. Histopathologic changes were observed in both sexes. Optic nerve degeneration was observed in a dose-dependent manner in the low-, mid-, and high-dose females, but was statistically significant only at the mid- and high-dose levels.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 100 was used to account for the interspecies differences and the spectrum of sensitivity in the human population, plus a 10-fold factor to account for the lack of a no-effect level.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD:
1) 2-Year Feeding (oncogenic) - rat: Principal study - see previous description; core grade minimum
2) 2-Year Feeding - dog: NOEL=1 ppm (0.025 mg/kg/day); LEL=2 ppm (0.05 mg/kg/day) (cholinesterase inhibition); core grade minimum (Mobay Chemical, 1975a)
3) 2-Year Feeding (oncogenic) - rat: RBC ChE and brain ChE: NOEL=1 ppm (0.05 mg/kg/day); LEL=2 ppm (0.1 mg/kg/day); Systemic Toxicity: No NOEL could be determined from available data. (Higher mortality in males at 2 ppm; in males, increase in both absolute and relative weights of spleen, liver, and pituitary, and decrease in both absolute and relative weights of brain and seminal vesicles; in females, decrease in both absolute and relative weight of kidneys); core grade supplementary (incomplete necropsy and histopathology data) (Mobay Chemical, 1975b)
4) Teratology - rat: Teratogenic NOEL=1.0 mg/kg/day (HDT); Fetotoxic NOEL=0.3 mg/kg/day, Fetotoxic LEL=1.0 mg/kg/day (incomplete ossification of the parietals and sternebrae); ChE NOEL=0.1 mg/kg/day; ChE LEL=0.3\mg/kg/day (depressed RBC and plasma ChE activity); Reproduction NOEL=1.0 mg/kg/day (HDT); Maternal NOEL=1.0 mg/kg/day (HDT); core grade minimum (Mobay Chemical, 1983)
5) Teratology - rabbit: Teratogenic NOEL=1.5 mg/kg/day (HDT); Maternal NOEL=1.0 mg/kg/day; Maternal LEL=1.5 mg/kg/day (mortality); core grade minimum (Mobay Chemical, 1982)
6) 3-Generation Reproduction - rat: RBC ChE in F3b litters and their parents LEL=2 ppm (0.1 mg/kg/day); Systemic Toxicity: In F3b litters at 10 ppm (0.5 mg/kg/day) (males and females had cloudy swelling and fatty infiltration in liver; also, females had mild nephropathy in kidney and males had juvenile hypoplasia in testes); Reproductive Effect: No NOEL could be determined from available data. (Reduced fertility and litter size in the first and third generation at 10 ppm dietary level); core grade supplementary (no data on litter weight at birth and their growth rate until weaned. No data on number of stillborn animals; no statistical analysis; incomplete necropsy reports and insufficient histologic data. (Mobay Chemical, 1965)
Data Gap(s): Rat Reproduction Study; Additional studies to evaluate the eye effects (functional impairment of the eye).
__I.A.5. Confidence in the Oral RfD
Study — High
Database — Medium
RfD — Medium
The principal study appears to be of good quality, although a NOEL is lacking for the critical effect; the study is given a high to medium rating. Additional studies appear to be of fair to good quality, and therefore, confidence in the database is considered medium to high. Confidence in the RfD is also considered medium to high.
__I.A.6. EPA Documentation and Review of the Oral RfD
Source Document — This assessment is not presented in any existing U.S. EPA document.
Other EPA Documentation — Pesticide Registration Standard, April 1984; Pesticide Registration Files
Agency Work Group Review — 05/14/1986
Verification Date — 05/14/1986
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 Disulfoton conducted in September 2002 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 — Disulfoton
CASRN — 298-04-4
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Disulfoton
CASRN — 298-04-4
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 — Disulfoton
CASRN — 298-04-4
Last Revised — 02/01/1990
_VI.A. Oral RfD References
Mobay Chemical Company. 1965. MRID No. 00057267, 00091104. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Company. 1975a. MRID No. 00073348. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Company. 1975b. MRID No. 00069966, 00154957. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Company. 1982. MRID No. 00147886. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Company. 1983. MRID No. 00129458. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Company. 1985. MRID No. 00129456, 00146873, 41115401. 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 — Disulfoton
CASRN — 298-04-4
Date |
Section |
Description |
---|---|---|
03/01/1988 | I.A.5. | Confidence levels revised |
02/01/1990 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory actions updated |
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. |
12/03/2002 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Disulfoton
CASRN — 298-04-4
Last Revised — 03/31/1987
- 298-04-4
- BAY 19639
- BAYER 19639
- DIMAZ
- DISULFATON
- Disulfoton
- DI-SYSTON
- DISYSTOX
- DITHIODEMETON
- DITHIOPHOSPHATE DE O,O-DIETHYLE ET DE S-(2-ETHYLTHIO-ETHYLE)
- DITHIOSYSTOX
- ENT 23,437
- FRUMIN AL
- FRUMIN G
- M-74
- NA 2783
- O,O-DIAETHYL-S-(2-AETHYLTHIO-AETHYL)-DITHIOPHOSPHAT
- O,O-DIAETHYL-S-(3-THIA-PENTYL)-DITHIOPHOSPHAT
- O,O-DIETHYL 2-ETHYLTHIOETHYL PHOSPHORODITHIOATE
- O,O-DIETHYL S-(2-ETHTHIOETHYL) PHOSPHORODITHIOATE
- O,O-DIETHYL S-(2-ETHTHIOETHYL) THIOTHIONOPHOSPHATE
- O,O-DIETHYL S-(2-ETHYLMERCAPTOETHYL) DITHIOPHOSPHATE
- O,O-DIETHYL-S-(2-ETHYLTHIO-ETHYL)-DITHIOFOSFAAT
- O,O-DIETHYL S-2-(ETHYLTHIO)ETHYL PHOSPHORODITHIOATE
- O,O-DIETIL-S-(2-ETILTIO-ETIL)-DITIOFOSFATO
- O,O-ETHYL S-2(ETHYLTHIO)ETHYL PHOSPHORODITHIOATE
- PHOSPHORODITHIOIC ACID, O,O-DIETHYL S-(2-(ETHYLTHIO)ETHYL) ESTER
- PHOSPHORODITHIONIC ACID, S-2-(ETHYLTHIO)ETHYL-O,O-DIETHYL ESTER
- RCRA WASTE NUMBER P039
- S 276
- S-2-(ETHYLTHIO)ETHYL O,O-DIETHYL ESTER of PHOSPHORODITHIOIC ACID
- SOLVIREX
- THIODEMETON
- THIODEMETRON