The image of water flowing from a tap being ignited with a lighter has become heavily associated with hydraulic fracturing in the minds of the public. But a recent research paper published by the National Ground Water Association’s peer-reviewed journal, Groundwater, suggests this widespread image may be a mirage. The paper, published in the May/June issue of the journal, details the results of a study of 1,701 water quality analyses from drinking water wells in northeastern Pennsylvania.
The study found that the use of hydraulic fracturing for natural gas extraction has not created pathways for rapid gas migration into shallow groundwater. Rather, the concentration of methane in the region’s groundwater is disproportionally high in water wells located in valleys, regardless of their proximity to shale gas wells. The findings suggest that the topography of the region, rather than shale gas development, explains elevated methane levels in Susquehanna County water wells. The paper’s authors extrapolate that the findings have significant implications for the understanding of risks associated with shale gas extraction.
The authors also examined the results of isotropic and molecular analyses of hydrocarbon gases from 15 water wells in Susquehanna County by the state Department of Environmental Protection and the EPA, and concluded that the gases in the water wells are most consistent with those found in the spaces around the casings of local gas wells. These gases originate in relatively shallow shale formations, and do not exhibit features consistent with gas produced from deeper Marcellus shale.
These findings, while significant, are very much consistent with numerous other studies across the nation, none of which have found an instance of methane contamination in water from the fracturing of shale well below the aquifer.