Tests of water in Pennsylvania downriver from sewage treatment plants that handle wastewater from natural gas drilling raised no red flags for radioactivity, the state Department of Environmental Protection said Monday.
All of the samples, taken in November and December, showed levels at or below the normal naturally occurring background levels of radioactivity, the agency said. All samples also showed levels below the federal drinking water standard for Radium 226 and 228, it said.
The DEP did not immediately release the actual results, or say what the tests showed on other gas-drilling related pollutants, if anything. It also did not say how long it has known about the results.
The department said it installed the sampling stations last fall to monitor the impact of Marcellus Shale gas drilling on water quality. The fast-growing industry in Pennsylvania produces vast amounts of chemically tainted and sometimes radioactive water that gushes from the ground when using a drilling technique known as high-volume hydraulic fracturing, or fracking.
Some of that wastewater is trucked to sewage treatment plants that discharge into rivers that also supply drinking water for many Pennsylvanians.
However, those sewage treatment plants are not equipped to remove all of the pollutants from the gas-drilling wastewater, such as the salty dissolved solids and chlorides that the wastewater picks up as it travels through the shale beds.
Until new regulations were imposed in August, Pennsylvania had been the only state to allow most of this wastewater to be discharged into rivers after only such partial treatment. Other states required most or all of the brine to be disposed of by injecting it deep underground.
With pressure from environmentalists and state officials building, energy companies that have been drilling hundreds of Marcellus Shale gas wells since 2008 started overhauling the way they handle their wastewater in Pennsylvania.
Of the 10.6 million barrels of wastewater that gushed from the wells in the final six months of 2010, at least 65 percent were recycled for use in drilling another gas well, a dramatic increase. But the records also show that at least 2.8 million barrels of well wastewater were sent to treatment plants that discharge into rivers and streams.
A review of state records shows most of the gas-drilling wastewater that was treated and discharged by sewage plants in the second half of 2010 found its way into eight waterways. Tests were performed on seven of those waterways _ the Monongahela; South Fork of Ten Mile Creek; Conemaugh; Allegheny; Beaver; Tioga; and the West Branch of the Susquehanna _ while the eighth waterway, Blacklick Creek in southwestern Pennsylvania is a tributary of the Conemaugh.
A total of 1,386 new Marcellus Shale gas wells were drilled in the state last year, up from 768 a year earlier. Thousands more well permits have been approved.