For the study, researchers examined 116 water wells in the Eagle Ford, Fayetteville and Haynesville shales across Arkansas, Louisiana and Texas. From the data, researchers found low-level concentrations of chemicals in some of the wells. However, the researchers believe these chemicals are most likely natural occurring. 

The researchers also studied methane levels in the wells and possible pathways for methane to enter drinking water supplies. According to the study, the methane found throughout the shale plays is believed to be naturally occurring – not from shale development. As the study’s abstract states:

“Methane isotopes and hydrocarbon gas compositions indicate most of the methane in the wells was biogenic and produced by the CO2 reduction pathway, not from thermogenic shale gas.”

This finding supports the myriad of other studies and reports that have concluded that fracking does not pose a significant risk to drinking water resources, including that of the U.S. Environmental Protection Agency’s (EPA) five year study, which found no evidence of widespread water contamination of drinking water from fracking. As the USGS study concludes:

“UOG [unconventional oil and gas] operations did not contribute substantial amounts of methane or benzene to the sample drinking-water wells.” (pg. F)