Elevated levels of radioactivity, salts and metals have been found in river water and sediments at a site where treated water from oil and gas operations is discharged into a western Pennsylvania creek, according to a Duke University study published in the journal Environmental Science & Technology.
The study examined the quality of shale gas wastewater from hydraulic fracturing, or fracking, and the stream water above and below the disposal site. It found that some of the discharged effluent is derived from the Marcellus shale gas flowback water, which is naturally high in salinity and radioactivity.
The radioactivity levels found in sediments near the outflow were at levels that “would only be accepted at a licensed radioactive disposal facility,” according to Robert B. Jackson, professor of environmental science at Duke and one of the study’s authors.
Avner Vengosh, professor of geochemistry and water quality at Duke University’s Nicholas School of the Environment, says the radium levels in the samples collected at the disposal site were about 200 times greater than in samples collected upstream from the plant.
While the treatment removes a substantial portion of the radioactivity — more than 90 percent of barium and radium — it does not remove any of the other salts including bromide, which increases the risks for formation of toxic disinfection byproducts in drinking water treatment facilities located downstream. The researchers also found that this facility contributes four-fifths of the total downstream chloride flow.
The oil and gas industry has made efforts to reuse or to transport shale gas wastewater to deep injection wells, but wastewater is still discharged to the environment in some states. Vengosh says releasing wastewater without adequate treatment should be stopped to protect freshwater resources.
US demand for water treatment chemicals will rise 3.2 percent per year to reach $6.7 billion in 2017, an increase driven by largely by the fracking boom as well as a rebound in manufacturing production, according to a study published this week by the Freedonia Group.
Omni Water Solutions last month announced it has treated more than 140,000 barrels of Marathon Oil’s flowback and produced water in Texas’ Eagle Ford shale since June to reduce boron and enable re-use of the cleaned water for fracking.
Photo Credit: Drill rig via Shutterstock