Ethyl p-nitrophenyl phenylphosphorothioate (EPN) (CASRN 2104-64-5)
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0236
Ethyl p-nitrophenyl phenylphosphorothioate (EPN);
CASRN 2104-64-5
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 EPN
File First On-Line 09/30/1987
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 — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
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 |
---|---|---|---|---|
Neurotoxicity 90-Day Hen Delayed Morabani, Nissan, |
NOEL: 0.01 mg/kg/day LEL: 0.1 mg/kg/day |
1000
|
1
|
1E-5
mg/kg/day |
*Conversion Factors and Assumptions — none
__I.A.2. Principal and Supporting Studies (Oral RfD)
Morabani American Corp., Nissan Chemical Ind. Inc., duPont de Nemours & Co., and Velsicol Chemical Co. 1982. MRID No. 00158314. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Adult hens (20/group) were dosed orally at 0.01, 0.1, 0.5, 1.0, 2.5, or 5.0 mg/kg/day for 90 days. Animals were observed daily for signs of delayed neurotoxicity; histopathology was performed on nerves after study termination.
1) Signs of O-P type delayed neurotoxicity (ataxia) were seen at doses of 2.5 and 5.0 mg/kg/day. NOEL = 1.0 mg/kg/day
2) Histopathologically observed damage to nervous system was seen at doses of 0.1 and up. NOEL = 0.01 mg/kg/day
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 1000 was used to account for inter- and intraspecies differences and for the fact that the NOEL was based on a subchronic exposure study.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Data Considered for Establishing the RfD:
1) 90-Day Delayed Neurotoxicity - hen: Principal study - see previous description; core grade guideline
2) 90-Day Feeding - rat: ChE NOEL=5 ppm (0.25 mg/kg/day); ChE LEL=25 ppm (1.25 mg/kg/day) RBC ChE inhibition; The effects noted at 125 ppm included decreased plasma and brain ChE activity, decreased female growth and decreased RBC, hemoglobin, and hematocrit in both sexes; core grade guideline (Morabani American Corp.; Nissan Chemical Ind. Inc.; du Pont; and Velsicol Chemical Co., 1986a)
3) 90-Day Feeding - dog: ChE NOEL=0.3 mg/kg/day; ChE LEL=1.0 mg/kg/day (Plasma ChE inhibition); Systemic NOEL=1.0 mg/kg/day; Systemic LEL=3.0 mg/kg/day (decreased RBC and brain ChE activity, decreased RBC, hemoglobin, and hematocrit in both sexes and pancreatic aciner cell atrophy in two males); core grade guideline (Morabani American Corp.; Nissan Chemical Ind. Inc.; du Pont; and Velsicol Chemical Co., 1986b)
4) Recovery Study - hen: Following a single dose of 175 mg/kg all hens showed severe damage in the spinal cord but only 1/3 of the hens showed signs of neurotoxicity (ataxia). Recovery from cordal damage was minimal over a period of 90-days postdose. (Morabani American Corp.; Nissan Chemical Ind. Inc.; du Pont; and Velsicol Chemical Co., 1986c)
Data Gap(s): Chronic Dog Feeding Study; Rat Reproduction Study; Teratology (Rat & Rabbit) - These studies have been received and are not yet reviewed. They appear to be acceptable and negative for developmental toxicity.
__I.A.5. Confidence in the Oral RfD
Study — High
Database — Medium
RfD — Medium
The principal study is of good quality and is given a high confidence rating. The subchronic data are supportive. However, since there are no data on chronic exposure toxicity, the database is given a medium confidence rating. Medium confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Files
Agency Work Group Review — 12/09/1986, 03/18/1987
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 Ethyl p-nitrophenyl phenylphosphorothioate (EPN) conducted in September 2002 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 — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
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 — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
Last Revised — 04/01/1991
_VI.A. Oral RfD References
Morabani American Corporation, Nissan Chemical Ind., Inc., E.I. du Pont de Nemours & Company, and Velsicol Chemical Company. 1982. MRID No. 00158314. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Morabani American Corporation, Nissan Chemical Ind., Inc., E.I. du Pont de Nemours & Company, and Velsicol Chemical Company. 1986a. MRID No. 00157874. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Morabani American Corporation, Nissan Chemical Ind., Inc., E.I. du Pont de Nemours & Company, and Velsicol Chemical Company. 1986b. MRID No. 00158890. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Morabani American Corporation, Nissan Chemical Ind., Inc., E.I. du Pont de Nemours & Company, and Velsicol Chemical Company. 1986c. MRID No. 00159372. 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 — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
Date |
Section |
Description |
---|---|---|
03/01/1991 | I.A.4. | Citations added |
03/01/1991 | VI. | Bibliography on-line |
04/01/1991 | VI.A. | MRID numbers added to citations |
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 — Ethyl p-nitrophenyl phenylphosphorothioate (EPN)
CASRN — 2104-64-5
Last Revised — 09/30/1987
- 2104-64-5
- BENZENEPHOSPHONIC ACID, THIONO-, ETHYL-p-NITROPHENYL ESTER
- ENT 17,798
- EPN
- EPN 300
- ETHOXY-4-NITROPHENOXYPHENYLPHOSPHINE SULFIDE
- ETHYL p-NITROPHENYL BENZENETHIONOPHOSPHONATE
- ETHYL p-NITROPHENYL BENZENETHIOPHOSPHATE
- ETHYL p-NITROPHENYL BENZENETHIOPHOSPHONATE
- ETHYL p-NITROPHENYL PHENYLPHOSPHONOTHIOATE
- Ethyl p-nitrophenyl phenylphosphorothioate
- ETHYL p-NITROPHENYL THIONOBENZENEPHOSPHATE
- ETHYL p-NITROPHENYL THIONOBENZENEPHOSPHONATE
- O-AETHYL-O-(4-NITRO-PHENYL)-PHENYL-MONOTHIOPHOSPHONAT
- O-ETHYL-O-((4-NITRO-FENYL)-FENYL)-MONOTHIOFOSFONAAT
- O-ETHYL O-(4-NITROPHENYL)BENZENETHIONOPHOSPHONATE
- O-ETHYL O-(4-NITROPHENYL) PHENYLPHOSPHONOTHIOATE
- O-ETHYL O-p-NITROPHENYL PHENYLPHOSPHONOTHIOLATE
- O-ETHYL O-p-NITROPHENYL PHENYLPHOSPHOROTHIOATE
- O-ETHYL PHENYL p-NITROPHENYL THIOPHOSPHONATE
- O-ETIL-O-((4-NITRO-FENIL)-FENIL)-MONOTIOFOSFONATO
- O-(4-NITROPHENYL) O-ETHYL PHENYL THIOPHOSPHONATE
- PHENYLPHOSPHONOTHIOATE, O-ETHYL-O-p-NITROPHENYL-
- PHENYLPHOSPHONOTHIOIC ACID O-ETHYL O-p-NITROPHENYL ESTER
- PHENYLTHIOPHOSPHONATE DE O-ETHYLE ET O-4-NITROPHENYLE
- PIN
- SANTOX