Elevated organic compounds in Pennsylvania drinking water from hydraulic fracturing surface operations, not gas wells

In the largest study of its kind, a Yale-led investigation found no evidence that trace contamination of organic compounds in drinking water wells near the Marcellus Shale in northeastern Pennsylvania came from deep hydraulic fracturing shale horizons, underground storage tanks, well casing failures, or surface waste containment ponds. The presence of organic compounds in groundwater aquifers overlying the Marcellus Shale is likely the result of surface releases from hydraulic fracturing operations and not migration from gas wells or deep shale layers, according to researchers in the lab of Desiree L. Plata, assistant professor of chemical and environmental engineering at Yale. The results of Brian Drollette, a Ph.D. student in Plata's lab, is the lead author. Due to its vast reserves of natural gas, the Marcellus Shale has become an active site for hydraulic fracturing. During a period of rapid natural gas well expansion, the researchers regularly visited the northeastern region of Pennsylvania, covering about 7,400 square kilometers, over three years and obtained 64 samples from the drinking water wells of residential properties. Using a suite of chemical analyses, the researchers found that a subset of the groundwater samples contained low levels of organic compounds in areas close to natural gas wells.