A recent Duke study seeks to support the possibility of fluid migration impacting drinking water supplies: "The report by researchers at Duke University, published yesterday in the Proceedings of the National Academy of Sciences, said a chemical analysis of 426 shallow groundwater samples found matches with brine found in rock more than one mile (1.2 kilometers) deep, suggesting paths that would let gas or water flow up after drilling." (from Bloomberg News, for example). But read a little further into the article: "Terry Engelder, a professor of geosciences at Pennsylvania State University who studies geological formations in the region, reviewed the Duke paper and recommended against publication in the journal, he said. *** 'The science on this paper is solid,' he said in an interview. 'It’s the leap of faith they take in their interpretation and to focus everybody’s attention on the Marcellus' gas drilling. *** It’s not clear how long it took for the brine to migrate into groundwater, and it could take thousands of years, he said. And once fracking takes place, gas and water will flow into the well and not up through any fissures that may exist. 'The natural flow would be into the well bore,” Engelder said." (Emphasis is ours.)
For a copy of the study, see here. From the paper itself: "The occurrences of saline water do not correlate with the location of shale-gas wells and are consistent with reported data before rapid shale-gas development in the region." (Emphasis is ours.) Interesting ...