Geochemical Tracers Can ID Fracking Flowback Fluids

Duke University geochemist Avner Vengosh, who co-led the research, said the research "gives us new forensic tools to detect if frack fluids are escaping into our water supply and what risks, if any, they might pose."

The National Science Foundation reports scientists have developed tracers that can identify hydraulic fracturing flowback fluids that have been spilled or released into the environment, and they have been field-tested at a spill site in West Virginia and downstream from an oil and gas brine wastewater treatment plant in Pennsylvania.

"By characterizing the isotopic and geochemical fingerprints of enriched boron and lithium in flowback water from hydraulic fracturing, we can now track the presence of 'frack' fluids in the environment and distinguish them from wastewater coming from other sources, including conventional oil and gas wells," said Duke University geochemist Avner Vengosh, who co-led the research. "This gives us new forensic tools to detect if frack fluids are escaping into our water supply and what risks, if any, they might pose."

The team published its findings this week in the journal Environmental Science & Technology. Their study was funded by NSF and is the first to report on the development of the boron and lithium tracers. "With increasing exploitation of unconventional oil and gas reservoirs through the use of hydraulic fracturing, it's important that we are able to assess the extent of hydraulic fracturing fluids entering the environment," said Alex Isern, section head in NSF's Division of Earth Sciences, which funded the research. "This work is critical as it demonstrates that geochemical fingerprinting provides a powerful tool to differentiate potential sources of contamination and therefore guide efforts to mitigate environmental impacts."

"The flowback fluid that returns to the surface becomes a waste that needs to be managed," Vengosh said. "Deep-well injection is the preferable disposal method, but injecting large volumes of wastewater into deep wells can cause earthquakes in sensitive areas and is not geologically available in some states. In Pennsylvania, much of the flowback is now recycled and reused, but a significant amount of it is still discharged into local streams or rivers."

Thomas Darrah of The Ohio State University, Robert Jackson of Duke and Stanford Universities, and Romain Millot and Wolfram Kloppmann of the French Geological Survey also co-authored the paper, which was partly funded by the Park Foundation.

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