High radioactivity levels of sediments above management regulations
The Duke study goes further, investigating the salinity and radioactive levels of sediments found outside hydraulic fracturing waste water facilities. The study examines the effects shale gas waste water has on stream water above and below the disposal sites. The study is crucial, noting how remaining radioactive waste is accumulating environmental toxicity for years to come. High concentrations of salts and even metals were observed in the nearby stream water.
"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," said Robert B. Jackson, professor of environmental science at Duke. "The facility is quite effective in removing metals such as barium from the water but concentrates sulfates, chlorides and bromides. In fact this single facility contributes four-fifths of the total downstream chloride flow at this point."
The study shows how Marcellus shale gas flowback water discharges effluent that still contains many salts, including bromide.
The water above and below the disposal site was tested and was found to be high in salinity and radioactivity, with elevated toxic metals like barium and strontium.
Bromide increases formation of toxic disinfection byproducts in drinking water
The Duke team states the severity of the toxic waste water: "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."
The Marcellus waste water was also tested and analyzed for radium isotopes in sediments from the bottom of the stream. The treatment facility effectively removes about 90 percent of radium and barium from the effluent, but sediment samples were recorded to have 2,072 Bq/kg (228Ra) and 8,732 Bq/kg (226Ra) - which is 200 times the background levels measured upstream of the treatment facility.
Duke scientists believe environmental damage to be seen for "thousands of years to come"
The team reiterates the severity of the situation: "Years of disposal of oil and gas waste water with high radioactivity has created potential environmental risks for thousands of years to come."
"This could be a long-term legacy of radioactivity," says Nathaniel R. Warner, postdoctoral researcher from Dartmouth College. "While water contamination can be mitigated by treatment to a certain degree, our findings indicate that disposal of waste water from both conventional and unconventional oil and gas operations have degraded the surface water and sediments."
They found that halogens such as bromide and chloride are not removed from the water at all, raising the alarm for new treatment methods that would help reduce salinity. According to scientists, there are better ways to reduce salinity and radioactivity, but the time cost, implementation, and monitoring have hindered the new methods.
Trying to find answers, the industry has tried reusing or transporting shale gas waste water to deep injection wells. It is unclear whether this helps at all, since the contaminated waste water still finds a way to pollute the surrounding groundwater.
Avner Vengosh, professor of geochemistry and water quality at Duke, believes the situation is dire, stating, "It is clear that this practice of releasing waste water without adequate treatment should be stopped in order to protect freshwater resources in areas of oil and gas development."
Sources for this article include:
Nathaniel R. Warner, Cidney A. Christie, Robert B. Jackson, Avner Vengosh. Impacts of Shale Gas Wastewater Disposal on Water Quality in Western Pennsylvania. Environmental Science & Technology, 2013; : 131002090059009 DOI: 10.1021/es402165b