IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR HYDROGEN SULFIDE (EXTERNAL REVIEW DRAFT)
Notice - This site contains archived material(s).
Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the NCEA Webmaster for assistance. Please use the contact form if you need additional assistance.
Subchronic inhalation of H2S has been shown to mainly affect the nasal mucosa in laboratory animals and been reported to increase seminiferous tubular degeneration and epididymal changes in rats exposed to 80 ppm (111 mg/m3) H2S. Three subchronic animal studies were considered for derivation of an inhalation RfC: the study by Brenneman et al. (2000) was considered to be the best study for derivation of an inhalation RfC. Nasal lesions were identified as the critical effects. Application of the RfC methodology yielded a NOAEL of 10 ppm (14 mg/m3) and a LOAEL of 30 ppm (42mg/m3). The LOAEL and NOAEL were then converted to continuous exposure by means of a dosimetric adjustment factor derived from the regional gas dose ratio (RGDR) for H2S in the extrathoracic (ET) region. The animal NOAEL is then multiplied by the RGDRET to yield the NOAELHEC. The RfC was derived by dividing the NOAELHEC for nasal effects by a total uncertainty factor of 300, yielding an inhalation RfC of 0.002 mg/m3 or 1 ppb. No data pertaining to the potential carcinogenicity of H2S were identified.
U.S. EPA. IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR HYDROGEN SULFIDE (EXTERNAL REVIEW DRAFT). U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Washington Office, Washington, DC, 2002.
This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.