Toxicological and Environmental Impacts of Hydrogen Sulfide

Hydrogen sulfide (H2S) is a very toxic gas at high concentrations. Because it occurs in nature and is produced by numerous industrial activities, it is regarded as both an environmental and industrial pollutant. It is colorless, is heavier than air, and has a characteristic odor of rotten eggs at low concentrations; however, at higher concentrations the olfactory response is lost. Because H2S can affect many different tissues and organs, it has been termed a broad spectrum toxicant. This chapter focuses on the toxicological effects on the respiratory tract, eye, brain, and olfactory system. An overview on dose-response relationships, sensitive populations, persistent effects, and mechanisms of action is also presented. In addition, a brief synopsis of the environmental effects of H2S is included. Although the toxicological and environmental impacts of H2S have been studied for many decades, there are still many concerns about the potential effects of low levels on humans and the ecosystem in general.