Evidence continues to mount of the devastating environmental effects of mountaintop mining (MTM) — the controversial practice of stripping the tops off of mountains to mine coal. The latest in a recent flurry of studies looking at activities in the Appalachian Mountains in West Virginia shows the cumulative effects of mountaintop mining on downstream water quality. (See Nature’s previous coverage here and here.)
Ty Lindberg, a stream ecologist at Duke University in Durham, North Carolina, and his colleagues collected and analysed water samples from 23 locations along the Upper Mud River and its tributaries. Of these sites, 21 were situated downstream of active and reclaimed mountaintop mines in the area.
They found that the concentration of pollutants such as selenium, which is toxic to fish, and the electrical conductivity of stream water — a measure of its ionic concentration — increased at a rate directly proportional to the extent of mountaintop mining upstream.
“Dangerous” levels of selenium could be found over 14 kilometres downstream of the permitted mining boundary, encroaching on the habitat of a large population of sunfish and bass, the researchers say.
“Our study provides further evidence showing that surface coal mining is responsible for increased levels of stream solutes and conductivity in the waters impacted by current and inactive MTM operations,” Lindberg says.
They also found persistently high conductivity and solute levels in streams draining from mines that have been inactive for nearly two decades. This suggests that current stream reclamation efforts may have limited success in reducing the mines’ effects on downstream organisms, the researchers say.
Picture of coal mining in the Upper Mud River study area courtesy of Scottee Cantrell. Copyright, National Academy of Sciences.