Provisional Advisory Levels (PALs) for hydrogen sulfide (H2S)
Thomas Marshall1, David Dorman, Donald Gardner
1Toxicology and Hazard Assessment Group, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA. marshalltc@ornl.gov
Inhalation Toxicology
|October 16, 2009
Summary
Provisional Advisory Levels (PALs) were developed for hydrogen sulfide (H2S) inhalation exposure. These health guidelines address varying toxic effect severities for short-term public exposure scenarios.
Area of Science:
- Environmental Health
- Toxicology
- Public Health
Background:
- Provisional Advisory Levels (PALs) are health-based guidance values for environmental contaminants.
- Hydrogen sulfide (H2S) is a gas with potential for widespread environmental release and public exposure.
Purpose of the Study:
- To establish Provisional Advisory Levels (PALs) for hydrogen sulfide (H2S) for various exposure durations.
- To inform public health risk assessment and management strategies for H2S exposure.
Main Methods:
- Utilized a comprehensive database including human experimental studies, worker evaluations, and animal studies.
- Applied established toxicological risk assessment methodologies to derive H2S PALs.
- Focused on inhalation exposure pathways due to the gaseous nature of H2S.
Main Results:
- Established 24-hour inhalation PALs for H2S: PAL 1 = 1.2 ppm, PAL 2 = 7.0 ppm, PAL 3 = 27 ppm.
- Derived 30-day and 90-day inhalation PALs: PAL 1 = 0.85 ppm, PAL 2 = 3.0 ppm.
- Determined insufficient data for oral exposure PALs and long-term (2-year) inhalation PALs.
Conclusions:
- Inhalation PALs for H2S were successfully developed for short-to-medium term exposures.
- Lack of oral exposure data precludes drinking water advisories.
- Further research is needed to establish long-term inhalation exposure guidelines for H2S.
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