INAPPROPRIATE USE OF SULFATE AS A CONSERVATIVE MARKER OF MINING IMPACTS TO GROUNDWATER AND SUBSEQUENT FAILURES IN REGULATORY PROTECTION

Sulfate, iron and manganese contamination from mining impacts are commonly monitored in ground water as a primary indicator of mining impacts, and sulfate is generally considered a conservative contaminant. In fact, many regulatory agencies rely heavily on these indicators and assume that if there are low concentrations of these contaminants in groundwater, mining impacts are not occurring. However, under conditions frequently found in groundwater, these contaminants can be reduced by iron and sulfate reducing bacteria, for example, creating conditions in which these contaminants can be precipitated in the subsurface or well, or converted to toxic sulfide gas, and therefore missed by standard contaminant monitoring. This in turn leads regulatory agencies to find no impact from mining operations in communities where other indicators clearly indicate impacts are present. This leads to a lack of protection in mining impacted communities and an increased risk of adverse human health impacts.