By Hannah Northey and Mike Soraghan

A new study is offering fresh evidence that unconventional oil and gas production is polluting surface waters — through higher salt concentrations — across several U.S. shale plays and watersheds.

The study published yesterday in Science found a correlation between newly drilled wells and salt concentrations, which indicate contamination from drilling. Concentrations were highest shortly after hydraulic fracturing of the wells.

“This study provides the first evidence that hydraulic fracturing is related to increased salt concentrations in surface waters across several U.S. shales and many watersheds,” the authors wrote.

The salt concentrations weren’t high enough to signal big problems, but the authors said their findings raise questions about the lack of data around other potentially more dangerous substances that could be reaching streams and ponds, like “forever chemicals” used in oil and gas production.

“There is not enough public data to analyze potentially more dangerous substances,” Christian Leuz, a professor at the University of Chicago and an author of the study, said in a Q&A released with the report. “There are limitations in available water quality measurements. Overall, our approach and evidence [suggest] impact. We need more research to evaluate this impact.”

Leuz and co‐authors Pietro Bonetti, an assistant professor at the University of Navarra, and Giovanna Michelon, a professor at the University of Bristol, analyzed a geocoded database that combined more than 60,000 surface water measurements from publicly available datasets over an 11-year period to establish a baseline of what’s normal in 408 watersheds across the country, from North Dakota to the East Coast’s Marcellus Shale play.

They then analyzed those measurements in relation to more than 46,000 horizontally drilled wells stimulated by hydraulic fracturing from dozens of shale plays across the country, data that came from WellDatabase, Enverus, the Pennsylvania Department of Environmental Protection, and the Pennsylvania Department of Conservation and Natural Resources.

Across all shale plays, Leuz and his colleagues found concentration increases of barium, chloride and strontium associated with new oil and gas wells that had been horizontally drilled, according to the report.

Concentrations increased shortly after the wells were hydraulically fractured, or “fracked,” and production began, the study found. During that time, the chemical-laced water used in the fracking process to crack open rock can return to the surface. Extremely salty water from the underground formation also starts coming up with the oil and gas, and the highest quantities flow early in production.

Continue Reading at E&E News…

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