Nitric oxide (CASRN 10102-43-9)
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0077
Nitric oxide;
CASRN 10102-43-9
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 Nitric oxide
File First On-Line 01/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | withdrawn | 09/01/1994 |
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 — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
The RfD for nitric oxide (nitrogen monoxide) has been withdrawn from IRIS on 09/01/1994 based on the fact that it is extremely insoluble in water (0.006 g/100 g of water at Standard Temperature and Pressure (STP); U.S. EPA, 1993) and the small amount that does dissolve (60 ppm) reacts with water to form nitrous acid or nitrites, depending on the pH.
In the presence of alkali (pH >7.0), nitrites are formed from nitrous acid. An RfD presently exists for nitrites and, as more fully explained in the IRIS file for nitrite, it is based on the fact that nitrites are capable of oxidizing hemoglobin (Fe++) to ferric hemoglobin (Fe+++), commonly referred to as methemoglobin. The inability of methemoglobin to combine with oxygen results in clinical effects due to tissue hypoxia.
U.S. EPA. 1993. Air Quality Criteria for Oxides of Nitrogen. Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Research Triangle Park, NC. EPA-600/8-91/049aF.
Agency Work Group Review — 08/19/1985, 02/26/1986, 06/24/1992, 08/04/1994
EPA Contacts:
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).
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 nitric oxide 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.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
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 — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
Last Revised — 09/01/1994
_VI.A. Oral RfD References
U.S. EPA. 1993. Air Quality Criteria for Oxides of Nitrogen. Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Research Triangle Park, NC. EPA-600/8-91/049aF.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
Date |
Section |
Description |
---|---|---|
03/31/1987 | I.A.6. | Documentation corrected |
08/01/1989 | VI. | Bibliography on-line |
08/01/1991 | I.A. | Oral RfD summary noted as pending change |
01/01/1992 | I.A.7. | Primary contact changed |
01/01/1992 | IV. | Regulatory actions updated |
09/01/1994 | I.A. | RfD withdrawn; replaced with permanent withdrawal msg |
09/01/1994 | VI.A. | Oral RfD references revised |
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 | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Nitric oxide
CASRN — 10102-43-9
Primary Synonym — Nitrogen monoxide
Last Revised — 01/31/1987
- 10102-43-9
- Bioxyde d'azote
- Nitric Oxide
- Nitrogen monoxide
- Nitrogen oxide, natural
- Nitrogen oxide (NO)
- Nitrosyl radical
- WLN: .N-O
- WLN: N O.