Due to an embargo break (which tells you someone thinks this is a hot story), PNAS just lifted the embargo on the paper “Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction,” by Robert B. Jackson of Duke University, et al.
They looked at water wells within 1 kilometer of trhe Marcellus shale gas wells in northeastern Pennsylvania and southeastern New York, and found that
"...82% of the wells analyzed contained methane; on average, methane concentrations were 6-times higher for homes located less than 1 km from drilling sites than for homes farther away. Concentrations of ethane and propane were also higher for homes located within 1 km of drilling sites. Furthermore, the authors found that distance to gas wells was the most significant factor to influence drinking water methane and ethane concentrations. In some cases, the chemical signature of the gases in drinking water was characteristic of a Marcellus-like source, according to the authors."From the article:
It will be interesting to see how this plays out....