IRIS Toxicological Review and Summary Documents for Hydrogen Sulfide (External Review Draft)
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Abstract
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.
Citation
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- Toxicological Review of Hydrogen Sulfide (External Review Draft) The purpose of this Toxicological Review is to provide scientific support and rationale for the hazard identification and dose-response assessment in IRIS pertaining to chronic exposure to hydrogen sulfide. It is not intended to be a comprehensive treatise on the chemical or toxicological nature of hydrogen sulfide. (PDF) (68 pp, 225 KB, about PDF)
- IRIS Summary - Hydrogen Sulfide (External Review Draft) (PDF) (11 pp, 28 KB, about PDF)
- Instructions to Peer Reviewers for Reviewing IRIS Summaries and Supporting Documentation for Hydrogen Sulfide (CAS No. 7783-06-4) (PDF) (3 pp, 97 KB, about PDF)