New study links mountaintop-removal coal mining to long-term damage to water supplies

A new scientific study released today "confirms the pervasive and irreversible impacts of mountaintop-removal coal mining here in Appalachia," writes Ken Ward Jr. of The Charleston Gazette on his Coal Tattoo blog. "Cumulative Impacts of Mountaintop Removal Mining on an Appalachian Watershed" appears in the Proceedings of the National Academy of Sciences and reveals a direct link between long-term water quality damage and mountaintop removal. The team of Duke University researchers said they compiled results from a single watershed in West Virginia, the Upper Mud River, because "water-quality impacts from other potential sources are largely absent." (Map locates Upper Mud watershed in Central Appalachian coalfield)

Ward writes that previous studies have shown the impact on stream water, biological community structure and ecosystem function from individual mines and adjourning valley fills, but "empirical data on the cumulative impacts of multiple mining operations on larger downstream rivers has been lacking." This study fills that gap by considering both active and reclaimed mines and their impact on water quality both near the sites and many miles upstream. Researchers said in a Duke news release that their results provide evidence that mines reclaimed 20 years ago still affect water quality. They also say this study will help those making strip-mine permit decisions.

Researchers sampled for electrical conductivity, salinity and "concentrations of major ions and trace elements derived from coal or its matrix rock." The Upper Mud flows through the Hobet 21 surface mining complex, one of the largest in Appalachia. According to the news release, researchers found "All conductivity measurements taken downstream of mine discharge outlets exceeded levels known to be harmful to aquatic life ... though, at the two sampling sites upstream of any mines, conductivity levels were within an acceptable range. Concentrations of selenium, a known fish toxin, followed a similar trend ... They also found deformities typical of selenium exposure in fish collected from downstream waters."

Researchers also said: "As eight separate mining-impacted tributaries flowed into the Upper Mud, conductivity and concentrations of selenium, sulfate, magnesium and other inorganic solutes increased proportionately. Nearly 90 percent of the variation in trace elements and salinity could be explained by the amount of upstream surface mining." (Read more) Short-term, paid access to the full text of the study can be found here.