Radioactive Fracking Wastewater Discharged in Pennsylvania Creek
High levels of radioactivity and salinity have been found in river water and sediments near a wastewater discharge site connected to a fracking operation in Pennsylvania.
A Duke University-led team of researchers collected sediment and water samples from a creek in western Pennsylvania where treated fracking wastewater is discharged. Fracking, or hydraulic fracturing, is a controversial method of natural gas extraction from shale deposits achieved by mixing water with sand and chemicals and injecting it into bedrock at high pressures. The process enables a level of natural gas extraction previously unattainable, but opponents decry the practice as a pollutant to groundwater.
Samples collected near where the Josephine Brine Treatment Facility discharges into Blacklick Creek were found with raduim levels 200 times greater than in samples collected just upstream from the treatment plant.
The researchers determined that some of the discharged water is flowback from the expansive Marcellus shale deposit, which is naturally high in salinity and radioactivity. The fracking wastewater is treated before it's released into the waterways, but the researchers say the treatment does not remove all unwanted matter.
"The treatment removes a substantial portion of the radioactivity, but it does not remove many of the other salts, including bromide," said Avner Vengosh, a geochemist at Duke. "When the high-bromide effluents are discharged to the stream, it increases the concentrations of bromide above the original background levels. This is significant because bromide increases the risks for formation of highly toxic disinfection byproducts in drinking water treatment facilities that are located downstream."
Robert Jackson, professor of environmental science at Duke, highlighted some causes of concern connected with the wastewater discharge.
"The radioactivity levels we found in sediments near the outflow are above management regulations in the U.S. and would only be accepted at a licensed radioactive disposal facility," he said. "The facility is quite effective in removing metals such as barium from the water, but it concentrates sulfates, chlorides and bromides. In fact this single facility contributes four-fifths of the total downstream chloride flow at this point."
Vengosh said that even though the treatment facility does a good job reducing barium levels is the wastewater, "the amount of radioactivity that has accumulated in the river sediments still exceeds thresholds for safe disposal of radioactive materials."
"Years of disposal of oil and gas wastewater with high radioactivity has created potential environmental risks for thousands of years to come," he said, adding that his team's study makes a clear case for the more adequate treatment of fracking wastewater.
"This could be a long-term legacy of radioactivity," said researcher Nathaniel Warner.
The researchers' work is published in the journal Environmental Science & Technology.