MININING IMPACTED GROUNDWATER AS A SOURCE OF HYDROGEN SULFIDE GAS IN HOMES

Mining and mineral processing can impact all environmental media, including groundwater, creating multiple exposure routes and mechanisms, and an abundance of organic and inorganic contaminants. Sulfate contamination from mining impacts is commonly monitored in surface and ground water as a primary indicator of mining impacts, and sulfate is generally considered a conservative contaminant. In fact, many agencies assume that if there are low sulfate concentrations in water, mining impacts are not occurring. However, under conditions frequently found in groundwater, sulfate can be reduced by naturally occurring sulfate-reducing bacteria, creating hydrogen sulfide. Worldwide, many communities that are adjacent to mining operations rely on groundwater as their primary potable water source. Hydrogen sulfide gas is a largely unrecognized contaminant in these areas. This study of communities in the central Appalachia region of the United States investigated sulfate and sulfide concentrations in water and sulfide concentrations in indoor air. This investigation found that when drinking water aquifers are contaminated, this sulfide is liberated as a gas during domestic water use, creating conditions in mining community homes where short-term and long-term exposure can exceed applicable health standards. Hydrogen sulfide is a contaminant associated with the same types of toxic effects as those found at increased prevalence in mining communities. Our investigation found that this occurs at a concentration and frequency that warrants monitoring as a commonly occurring mining-related contaminant and potential public health hazard. Additionally, the lack of sulfate should not be used as proof that mining impacts are not occurring to groundwater.