- Associated Press - Wednesday, March 4, 2015

CHEYENNE, Wyo. (AP) - More data are needed to be able to fully assess whether any widespread correlation might exist between recent oil and gas development in the U.S. and degraded quality of nearby surface water, a new study by the U.S. Geological Survey suggests.

The study published in the American Geophysical Union journal Water Resources Research examined water quality data from 1970-2010 in areas with recent oil and gas drilling. The authors wrote they could document no trends involving surface water pollution in areas with increased unconventional oil and gas development, including hydraulic fracturing.

However, existing data to investigate long-term water quality trends are adequate in just 16 percent of U.S. watersheds with unconventional oil and gas resources, the authors wrote.

“In terms of a big splash or sensational finding, this isn’t it. At the same time, we thought it was worth reporting that if people had the idea that if everything is documented carefully throughout the United States, and we have these wonderful data resources, it isn’t the case,” the study’s lead author, Zachary Bowen at the Geological Survey science center in Fort Collins, Colorado, said Wednesday.

The researchers analyzed existing data from the Geological Survey and U.S. Environmental Protection Agency for chloride content and specific conductance in waters in areas with increasing oil and gas development.

Both specific conductance - measurement of water’s ability to carry an electric current - and chloride can signal water pollution. Sources could include the salty groundwater sometimes pumped to the surface as a byproduct of deep oil and gas development.

Chloride and specific conductance aren’t necessarily the best indicators of pollution from oil and gas development, however.

“A lot of the organics and compounds that would be more tightly associated with oil and gas, they’re not sampled frequently enough to be able to analyze even in the limited number of sites we were able to analyze them,” Bowen said.

The study published online Jan. 30 mentioned that chemicals used in hydraulic fracturing - the process of pumping pressurized volumes of water mixed with fine sand and chemical products into wells to crack open deposits containing oil and gas - can affect human health.

Environmentalists have sounded the alarm that fracking can pollute groundwater, a contention disputed by the petroleum industry.

The authors discussed several recent cases in which oil and gas development has been suspected of causing surface water and groundwater pollution. Among them was the EPA’s disputed 2011 draft finding that hydraulic fracturing might have played a role in groundwater quality problems near the central Wyoming community of Pavillion.

Challenges to studying the issue include variation in water testing requirements and formats between states and their environmental regulatory agencies. Also, surface and groundwater quality data from before oil and gas development occurs is “sparse or nonexistent,” the authors wrote.

“There really isn’t a national, long-term program to look at this stuff,” Bowen said.

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