Study says stray methane gas in drinking water is more abundant closer to gas wells

On June 24, 2013, Robert Jackson, the Nicholas Professor of Global Environmental Change at Duke University, published a study that detailed the relationship between methane, propane and ethane found in drinking water wells, and the proximity of the well to hydraulic fracturing sites. The 2013 study followed a 2011 study of sixty drinking water wells in the northeast Pennsylvania Marcellus region. After it was published, the 2011 study received criticism from the gas industry for not testing enough wells, and failing to demonstrate that the increased levels of methane were a given consequence of drilling, rather than faulty well casing or cementing. The 2013 study surveyed an additional 81 wells in the region, including wells from Ostego County in New York (where fracking has not been conducted).

The study showed an increased concentration of methane gas in drinking water from wells closer to a drilling site. Specifically, water wells within one kilometer of gas wells exhibited six times the concentration of methane of other wells. The methane gas in the water wells consistently bore a thermogenic signature (which matches signatures of methane trapped in the deeper shale formations currently being drilled), rather than a biogenic signature (which matches shallower pockets of methane).

The study offered two explanations for the increased presence of methane. First, it acknowledged the possibility of inadequate steel casings in gas wells; and second, it suggested imperfections in cement sealings between casings in gas wells could be responsible for the methane’s presence in water wells.

For more information on the study, visit the website for the Proceedings of the National Academy of Sciences (PNAS).

Written by: Garrett Lent, Research Assistant

Agricultural Law Resource and Reference Center

June 2013