The U.S. Geological Survey (USGS) released a pair of studies today detailing the discovery of low-to-moderate concentrations of naturally occurring methane in private water wells. The wells are located in a region of the Marcellus Shale where drilling is absent, according to StateImpact, a reporting project of National Public Radio member stations.
The two counties examined in the study, Wayne and Pike, are under the jurisdiction of the Delaware River Basin Commission, which currently has a freeze on drilling activity. According to USGS researcher Ronald Sloto, the baseline numbers found in these studies are extremely important. He said, “People are very concerned about the environmental impact of shale gas drilling. In order to assess the impact of something, you need a ‘before’ and an ‘after’. Then you compare the two and see what the changes are.”
Well samples were examined between 2012 and 2013. In Wayne County, 34 private water wells were inspected and Sloto discovered that 65 percent of these wells had levels of detectable methane. Relatively high levels of methane were found in 10 percent of the wells. Of the 20 wells tested in Pike County, 80 percent had detectable methane and only 10 percent had elevated levels.
The existence of naturally occurring methane, however, does not exempt the oil and gas industry from the responsibility of tainting some water supplies, the researchers noted. Although methane in water supplies can occur naturally, it can also find its way into the reservoirs due to defective well casings.
The findings of the study are congruent with a different USGS study performed in New York, which also has a moratorium on fracking. The research found naturally occurring methane to be common in private water wells.
Private water wells in Pennsylvania are not regulated, though, sometimes making it difficult to tell if the contamination happened before or after drilling operations. Currently, companies perform routine baseline water testing before the start of a well’s development.
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