“The isotope work is quite helpful and can be used to fingerprint the source,” said Tom Richard, director of Pennsylvania State University’s Institute for Energy and the Environment. Shallow natural gas is quite common in Pennsylvania and has a different isotopic pattern from the deeper sources in the Marcellus. To track the source of the gases, Vengosh and his colleagues analyzed elemental variations called isotopes, which provide a birth mark of sorts for the gas. The Marcellus formation lies much deeper, between 1,500 meters and 2,500 meters below ground.ĭrilling for shale gas in the Marcellus took off in 2009 when the number of wells quadrupled compared to the previous year. The researchers took water samples from 141 wells drilled to a depth of 60 meters to 90 meters, 59 of which were within one kilometer of a drilling site. “You don’t find those components outside of the Marcellus formation and there is no biological source,” Vengosh, a professor of geochemistry and water quality at Duke’s Nicholas School of the Environment, told Circle of Blue. Propane was found less often, in just 10 samples, all within one kilometer of a gas well.įinding both ethane and propane in the samples is evidence that drilling operations rather than natural seeps, as industry boosters like to claim, are contaminating groundwater, said Avner Vengosh, a study co-author. Ethane was found in 30 percent of the water samples, and concentrations were 23 times higher for samples taken within one kilometer of drilling sites. Researchers measured concentrations of two other gases associated with natural gas extraction, ethane and propane. “You don’t find those components outside of the Marcellus formation and there is no biological source.” The new study, however, tested water supplies for more than just methane and found a stronger correlation with fracking. None of the three studies has found groundwater contamination from the chemicals used in hydraulic fracturing, also called fracking. Led by researchers at Duke University, the study is consistent with the results of two other Duke studies that found methane contamination in water wells in Pennsylvania’s Marcellus shale formation and a hydrological connection between deep and shallow aquifers. The authors suggest that poorly constructed gas wells are the most likely source of contamination, an assumption that will be addressed more rigorously in a future paper. Methane was found in 82 percent of samples. Distance also plays a role in water contamination caused by hydraulic fracturing, the production technique that is splitting open shale rock to release trapped gas and powering the energy boom.ĭrinking water wells within one kilometer of shale-gas drilling sites in northeastern Pennsylvania had methane levels six times higher on average than wells farther away, according to a study published online Monday in the Proceedings of the National Academy of Sciences. In the United States’s new natural gas game, distance matters to the bottom line – distance to water supplies, to waste disposal sites, and to hungry foreign markets. Drinking water wells within one kilometer of drilling sites show higher levels of methane, according to a study published Monday in the Proceedings of the National Academy of Sciences. A natural gas drilling site operates adjacent to a farm in northeastern Pennsylvania.
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