Study: Methane in Pennsylvania Water Unrelated to Fracking
(Flickr/Simon Fraser University)
Methane found in drinking water in northeastern Pennsylvania is unrelated to nearby fracking wells, a new study found after analyzing more than 11,300 water samples from the region.
These findings run contrary to previously found associations between the practice of unconventional oil and gas drilling, known as hydraulic fracturing or fracking, and contaminated drinking water, one of the most controversial aspects of environmental health today.
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"It's the largest data set I've ever seen of natural water chemistry," Siegel said, noting that previous research — particularly two heavily publicized studies from Duke University published in the Proceedings of the National Academy of Sciences — had much smaller data sets and in some cases, zeroed in on areas with wells already known to be faulty and therefore more dangerous to the surrounding region.
After testing thousands of samples near 661 pre-existing oil and gas wells, Siegel and his colleagues found no association between fracking and higher methane levels in tap water.
Methane permeates water in the Appalachian basin due to the widespread shale rock formations in the area, which cause the gas to form naturally.
"A USGS [United States Geological Survey] study of methane reported that they could not find any water without methane in it," Siegel said. "People seem to think that is something unusual and toxic and so forth, but people have been drinking this for decades and decades."
That said, Siegel acknowledges some poorly engineered wells have had safety problems, which could cause naturally occurring chemicals or those used during the gas-extraction process to leak into nearby groundwater, such as in the infamous case of Dimock, Pennsylvania. Residents of that town appeared in the documentary Gasland lighting their tap water on fire.
Robert Jackson, lead author of the PNAS studies, told Science that he doubted the accuracy of Chesapeake's sampling techniques — though Siegel said they are standard methods. (The samples were collected via taps in nearby homes, unless a water purification system was in place, in which case, the company sampled prior to the water's processing, called an inverted bottle technique.)
Eric Hand wrote for Science that both agree that faulty, poorly engineered wells are the main safety problem; the point of contention is how often these risks occur.
Other studies have found additional health risks associated with fracking unrelated to methane in drinking water; the uncertainty surrounding these studies led the state of New York to ban fracking, citing health risks, in late 2014.
Siegel's team is set to publish additional studies using the Chesapeake data set, so the debate is sure to burn on.
The new paper is published in Environmental Science and Technology.