River water in western Pennsylvania has elevated levels of radioactivity, some of it from fluids discharged after natural gas extraction, says a Duke University study today that's likely to stir more controversy over the booming business of "fracking."
Radium levels were about 200 times greater in sediment from a creek where wastewater was discharged from a treatment plant than in sediment upstream, according to the peer-reviewed study in the Environmental Science & Technology journal. The amount exceeded thresholds for safe disposal of radioactive waste.
"We were surprised by the magnitude of radioactivity," says co-author Avner Vengosh, geochemistry professor at Duke's Nicholas School of the Environment. "It's unusual to find this level," he says, urging that other sites be investigated and that such water not discharged.
Treatment plants can remove much of the radioactivity and chemicals -- but not all, the Duke study says. Between August 2010 and November 2012, researchers sampled sediment from Blacklick Creek, where wastewater was discharged by the Josephine Brine Treatment Facility about an hour east of Pittsburgh and compared it with stream water above and below the disposal site. It found that some of the effluent came from Marcellus Shale fluids, which are naturally high in salinity and radioactivity.
The study is the latest in a bevy of research into the environmental impacts -- both water and the air -- of hydraulic fracturing or fracking. In this process, which has contributed to a surge in U.S. natural gas production, water mixed with sand and potentially toxic chemicals is blasted underground to break apart shale rock and release the gas.
An earlier Duke study, released in June by some of the same authors, found that drinking water wells near fracking sites in northeastern Pennsylvania were six times more likely to be contaminated than other wells. Other research has linked earthquakes to wells where fracking's wastewater is injected deep underground.
But other research has found little harm from fracking. Duke and federal scientists, in a study released earlier this year, found no evidence that shale gas production in Arkansas caused groundwater contamination. A Department of Energy study this year also found no proof that fracking chemicals tainted drinking water aquifers at a western Pennsylvania drilling site.
Scientists attribute the mixed research results to varying geology and industry practices nationwide. Fracking fluids are sometimes reused or disposed of in deep injection wells, but in some cases, they are treated and released into public waterways.
Years of such disposal have created "potential environmental risks for thousands of years to come," says Vengosh, adding that the water will need to be cleaned.
Industry officials say fracking is safe, when properly managed, because the wastewater is diluted in rivers and municipalities treat it again before providing it as drinking water.
"The real problem is we don't have a good handle on the full range of risks posed by treatment and discharge" of water from oil and gas fields, says Scott Anderson, a drilling expert with the Environmental Defense Fund, a research and advocacy group.
In May, the U.S. Environmental Protection Agency (EPA) fined Fluid Recovery Services, which acquired the Josephine plant in a merger, $83,000 for discharge violations from that facility and two others in Pennsylvania. It required the company, which was bought this year by Aquatech International, to invest $30 million in upgrades before it can discharge more fracking wastewater. The EPA said the facilities stopped such discharges in September. 2011.
"What's lacking is enforced monitoring," Vengosh says, noting that the samples collected by Duke suggest that radioactive water was still being discharged in 2012. He says more research is needed.
Next year, the EPA is expected to release a draft of its own study on fracking's potential impact on drinking water supplies.
By Wendy Koch