Naturally occurring radiation brought to the surface by gas drillers has been detected in a Pennsylvania creek that flows into the Allegheny River, illustrating the risks of wastewater disposal from the boom in hydraulic fracturing.
Sediment in Blacklick Creek contained radium in concentrations 200 times above normal, or background levels, according to the study, published in the journal Environmental Science and Technology.
The radium, along with salts such as bromide, came from the Josephine Brine Treatment Facility about 72km east of Pittsburgh, a plant that treated wastewater from oil and gas drilling.
"The absolute levels that we found are much higher than what you allow in the US for any place to dump radioactive material," Avner Vengosh, a professor at the Nicholas School of the Environment at Duke University and co-author of the study, said.
"The radium will be bio-accumulating. You eventually could get it in the fish."
Hydraulic fracturing or fracking has been blamed for contaminating streams and private water wells after spills from wastewater holding ponds or leaks from faulty gas wells.
The report exposed the risks of disposing of the surging volumes of waste from gas fracking. The US Environmental Protection Agency was developing new standards for disposing of gas drilling waste.
For decades, Pennsylvania disposed of wastewater from oil and gas drilling at commercial treatment plants that discharged into rivers and streams.
A natural-gas boom brought on by fracking in a geologic formation called the Marcellus Shale led to a 570 per cent increase in the volume of drilling wastewater since 2004, according to Brian Lutz, assistant professor of biogeochemistry at Kent State University in Kent, Ohio.
In fracking, millions of gallons of chemically treated water and sand were forced underground to shatter rock and free trapped gas.
As much as 80 per cent of the fluid returned to the surface along with radium, and salts such as sodium, calcium, magnesium, chlorine, bromide.
Water treatment "has been Pennsylvania's go-to method for decades," Lutz said in an interview.
With fracking "we were seeing these systems being overwhelmed. They were just taking too much waste leading to water quality problems."
While earlier studies have identified radiation in drilling wastewater, the new report was the first to examine the long-term environmental impacts of dumping it in rivers.
Proper treatment could remove a substantial portion of the radioactivity in wastewater, though it did not remove many of the other salts, including bromide, Vengosh said.
"Our findings indicate that disposal of wastewater from both conventional and unconventional oil and gas operations has degraded the surface water and sediments," Nathaniel Warner, a postdoctoral researcher at Dartmouth College and co-author of the study, said in a statement.
"This could be a long-term legacy of radioactivity."
Blacklick Creek was a tributary of the Conemaugh River, which flowed into the Allegheny.
In 2011, regulators found high levels of bromides in western Pennsylvania rivers, prompting some plants that supply Pittsburgh and other cities to change the way they treat drinking water.
Bromide, which was not toxic, could combine with disinfectants used at drinking water treatment plants to produce cancer-causing compounds.
Radium was a naturally occurring metal that could accumulate in plants and animals and be transferred through the food chain to humans, according to the Centers for Disease Control.
"We're getting better at reducing the amount of wastewater produced by shale gas wells, but the total wastewater volume continues to grow rapidly," Lutz said.
"There simply isn't disposal infrastructure in place."
In 2011, the Pennsylvania Department of Environmental Protection asked Marcellus Shale drillers to voluntarily stop taking wastewater to the Josephine plant and 14 others that had yet to meet new discharge standards.
Aquatech agreed in a May settlement with the state not to treat Marcellus Shale waste at Josephine and two of its other plants until they were upgraded to new standards.
The company also agreed to spend up to US$30 million (NZ$36m) to upgrade the three plants and to pay an US$83,000 (NZ$100,000) penalty.
The Josephine plant, which was acquired in May by Aquatech International Corp, stopped treating Marcellus Shale waste after the 2011 state advisory was issued, according to Devesh Mittal, vice president and general manager of the shale gas division at the closely held company.
"There's a very brief period of time when unconventional was treated," Mittal, who had not seen the study, said.
"But that kind of stopped as a result of the DEP notification that came in April of 2011."
Patrick Creighton, a spokesman for the Marcellus Shale Coalition, an industry group, said he had not seen the report and could not comment.
- WASHINGTON POST
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