In a study to be released this week, researchers from Duke’s Nicholas School of the Environment found gases related to fracking in drinking water wells near drilling sites in Pennsylvania.
By Taylor Sisk
As the debate over the future of hydraulic fracturing, or fracking, in North Carolina rages on, a Duke University-led team of researchers has found the drinking water in homes in a natural gas-rich area in northeastern Pennsylvania contains traces of methane, ethane and propane.
In research to be released later this week in the online edition of the journal Proceedings of the National Academy of Sciences, Robert Jackson, a professor of environmental sciences at the Duke University Nicholas School of the Environment, tested 141 wells near active drilling operations in the Marcellus shale region. He found 82 percent of the wells held traces of methane.
Concentrations were six times higher, on average, in homes located within a kilometer of drilling sites than in homes farther out.
Methane is the primary component of natural gas.
Concentrations of ethane and propane were also higher in homes located closest to drilling sites. Ethane concentrations were 23 times higher in wells within a kilometer of drilling operations. Propane was found in samples from 10 homes, all within a kilometer of drilling sites.
Jackson and his colleagues wrote that distance from gas wells was, by far, the most significant factor influencing gases in the sampled drinking water.
In North Carolina, the House and Senate have proposed dramatically different legislation for the future of fracking in the state. Last week, the two chambers selected five members each to hash out their differences behind closed doors.
Fracking is a process in which water, sand and chemicals are pumped at high pressure into underground horizontal gas wells for the purpose of cracking open shale to extract natural gas.
Among the concerns raised by opponents of fracking is the risk of contaminating drinking water.
“The EPA does not regulate methane in drinking water,” Jackson said in an interview Tuesday.
He said to his knowledge, no peer-reviewed studies examining the long-term health consequences of methane in drinking water have been conducted.
“To me, that’s a really interesting gap,” Jackson said. “There’s no literature that looks at that, and I think there should be some medical studies done.”
He said the only known risk would be in unusual circumstances where the methane might build up in a closed space, such as a basement, and cause an explosion or fire.
Jackson said in a press release issued on Monday that this data on ethane and propane contamination are “new and hard to refute.”
“There is no biological source of ethane and propane in the region and Marcellus gas is high in both,” he said.
The source of the Marcellus gas in the drinking water, he said on Tuesday, was probably a crack in the steel tubes through which the gas is lifted or a joint that’s not sealed properly.
“If you have Marcellus gas,” he added, “then it’s possible you’ll get other things coming up from underground through time, including, possibly, the fracking chemicals.”
“Our studies demonstrate that distances from drilling sites, as well as variations in local and regional geology, play major roles in determining the possible risk of groundwater impacts from shale gas development,” Avner Vengosh, a professor of geochemistry and water quality at the Nicholas School wrote in the press release. “As such, they must be taken into consideration before drilling begins.”
Natural gas industry officials have challenged the findings. Steve Everley of the industry advocacy group Energy In Depth wrote that naturally occurring methane is ubiquitous in water wells throughout northeast Pennsylvania.
Jackson said that he’s not suggesting there’s a problem with all drilling operations. Research conducted by his team in Arkansas found no contaminants.
He said he and his colleagues are working in five or six states at present and would be expanding to other areas.
“Ultimately, our goal is to help solve the problems,” he said. “We want to understand why some homeowners have problems and how to keep them from happening other places.”
Reporting on environmental health issues in North Carolina Health News is supported by a grant from the Park Foundation.