Numerous drinking-water wells across the country have been contaminated by natural gas in recent years, and many people have blamed hydraulic fracturing, more commonly known as fracking. However, a new paper which was published in the Proceedings of the National Academy of Sciences on Monday suggests that fracking may not be the cause.
A team of researchers at Duke University, Stanford University, Dartmouth University, and the University of Rochester recently devised a new method of geochemical forensics to trace how methane migrates under the earth. The study identified eight collections of drinking-water wells that had been contaminated by natural gas in Pennsylvania and Texas.
What the team found was that neither horizontal drilling nor hydraulic fracturing of shale deposits in the area seemed to have caused any of the natural gas contamination. Rather, the contaminations seem to be cause by poorly built and cemented gas wells, rather than the process of fracking itself.
“There is no question that in many instances elevated levels of natural gas are naturally occurring, but in a subset of cases, there is also clear evidence that there were human causes for the contamination,” said study leader Thomas Darrah, assistant professor of earth sciences at Ohio State. “However our data suggests that where contamination occurs, it was caused by poor casing and cementing in the wells,” Darrah said.
Read more about the story at The New York Times.