Contaminated water in Barnett Shale and Marcellus Shale from gas well leaks, study finds

A study by five universities found that contaminated drinking water in wells in North Texas’ Barnett Shale and the Marcellus Shale in Pennsylvania were not caused by drilling or hydraulic fracturing, but from gas that "leaked from defective casing and cementing in gas wells meant to protect groundwater or from gas formations not linked to zones where fracking took place," Randy Lee Loftis reports for The Dallas Morning News.

The study, by researchers from Ohio State University, Duke University, Stanford University, Dartmouth College and the University of Rochester, was published in Proceedings of the National Academy of Sciences. Researchers "took samples from wells in which gas levels had risen over time, clustered in seven locations in western Pennsylvania’s Marcellus Shale and one in the Barnett region."

Lead author Thomas Darrah told Loftis, "This is relatively good news because it means that most of the issues we have identified can potentially be avoided by future improvements in well integrity." He said the gas “is definitely not released by hydraulic fracturing breaking out of the shale and migrating into groundwater.” (Read more) (To view the interactive map click here)