Read the study CHARLESTON, W.Va. -- A new study in a major scientific journal confirms previous findings that link mountaintop removal coal mining to significant degradation of downstream water quality.The study, published in the Proceedings of the National Academy of Sciences, found increased salinity and metals in waters downstream from mining operations at Patriot Coal's Hobet 21 complex along the Boone-Lincoln County border.Duke University researchers Ty Lindberg and Emily Bernhardt, along with five other researchers, co-authored the paper, called, "Cumulative impacts of mountaintop mining on an Appalachian watershed.""Our results demonstrate that the cumulative impact of multiple mines within a single catchment and provide evidence that mines reclaimed nearly two decades ago continue to contribute to significant water quality degradation within this watershed," said the paper, published online on Monday.Coal industry officials favor mountaintop removal for its efficiency, and most coalfield political leaders support the practice.But federal regulators and citizen groups point to a growing body of scientific evidence that shows mountaintop removal causes serious damage to Appalachian forests and streams, and to newer research that strongly suggests a link between mountaintop removal and adverse health effects.Duke researchers sought to assess the cumulative impacts of more than 100 permitted discharge outlets draining about 11 square miles of active and reclaimed mountaintop removal permits at Hobet 21, in the Upper Mud River watershed.The Upper Mud flows through Boone and Lincoln counties as a headwater stream until it reaches the Mud River reservoir about 15 miles downstream. For about six miles, the river passes through the Hobet 21 complex, which has been active since the 1970s and is frequently touted by the industry as a well-run mountaintop removal operation with quality reclamation practices.Duke researchers collected 152 sets of samples from 23 sites, including two sites upstream from mining sites, between May and December 2010. They sampled for electrical conductivity, a measure of salinity, and for concentrations of major ions and trace elements derived from coal or the surrounding rocks.Co-author Richard Di Giulio said all conductivity measures taken downstream from mine discharge outlets "exceeded levels known to be harmful to aquatic life." Upstream from mining, conductivity measures were within safe levels."As eight separate mining-impacted tributaries flowed into the Upper Mud, conductivity and concentrations of selenium, sulfate, magnesium and other inorganic solutes increased proportionately," said co-author Avner Vengosh. "Nearly 90 percent of the variation in trace elements and salinity could be explained by the amount of upstream surface mining."Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.