Hydrofracking resulting in radioactive contaminants in wastewater
The Marcellus Shale, encompassing 104,000 square miles across Pennsylvania, West Virginia, Ohio, and upstate New York, is the largest source of natural gas in the US. Since 2008, hydraulic fracturing has been used to release and capture the shale gas for energy consumption. The use of hydrofracking has been highly disputed, and recent findings by Duke University further display the harmful impacts of fracking.
According to Avner Vengosh, professor of geochemistry and water quality at Duke University’s Nicholas School of the Environment, high concentrations of radioactivity, salts, and metals have been found downstream from a wasterwater treatment plant in a western Pennsylvania creek. The plant is used to remove specific metals from hydraulic wastewater, but the Duke team found that certain metals, such as chlorides and bromides, haven’t been successfully removed. In fact, they contribute to four-fifths of the total downstream chloride flow.
"The treatment removes a substantial portion of the radioactivity, but it does not remove many of the other salts, including bromide," Vengosh said. "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."
Furthermore, the amount of radioactivity that has accumulated in the river sediments exceeds the thresholds for safe disposal of radioactive materials, according to Vengosh. They are above management regulations in the US and would only be accepted at a licensed radioactive disposal facility. "Years of disposal of oil and gas wastewater with high radioactivity has created potential environmental risks for thousands of years to come," said Vengosh.
"While water contamination can be mitigated by treatment to a certain degree, our findings indicate that disposal of wastewater from both conventional and unconventional oil and gas operations has degraded the surface water and sediments," said Nathaniel R. Warner, a recent Ph.D. graduate of Duke who is now a postdoctoral researcher at Dartmouth College. "This could be a long-term legacy of radioactivity."
Despite current wastewater treatment plants and efforts made to transport the wastewater to deep injection wells, wastewater is still discharged into the environment in several locations, allowing radioactive sediments to leach into downstream waters.
Read more from Duke University.
Marcellus Shale Drilling image via West Virginia Sierra Club.