Image courtesy of IUCNweb/Flickr.

A group of scientists from some of America’s top universities found that poor well construction, not hydraulic fracturing, is to blame for fugitive methane contamination in water wells above the Marcellus and Barnett shale plays.

The study, published Monday in the Proceedings of the National Academy of Science, found that leaking well shafts caused the contamination of well water around fracking sites.

The researches – who came from Duke University, Ohio State, Stanford, Dartmouth College and the University of Rochester – studied 133 drinking water wells and one natural methane seep in the Marcellus play and 20 wells overlying the Barnett shale formation.

The study concluded that contamination in the water wells was caused by poor quality casing and cementing of drilling wells in the surrounding area, not the fracking process itself.

“These results appear to rule out the possibility that methane has migrated up into drinking water aquifers because of horizontal drilling or hydraulic fracturing, as some people feared,” said professor geochemistry and water quality at Duke University Avner Vengosh.

The researchers said the study demonstrates the need for a regulatory framework that ensures wells are properly constructed and maintained in order to avoid water well contamination.