The state Department of Environmental Protection will begin a study examining whether the waste materials generated from natural-gas drilling contain excessively high levels of radioactivity, the agency said last week.
During the next year to 14 months, DEP said, it intends to sample and analyze "flowback water, rock cuttings, treatment solids and sediments" at every stage from drilling to disposal.
The process of drilling and fracking Marcellus Shale wells uses millions of gallons of water, and drillers send tons of sediment and drill cuttings to state landfills. Environmentalists have raised concerns that the naturally occurring radioactivity from the deep rock formations that drillers tap might be present in these byproducts at levels high enough to pose long-term risks.
DEP "routinely reviews radioactivity data" and said it has found no cause for concern. In addition, Pennsylvania requires landfills to monitor incoming waste for radioactivity. The waste has occasionally tested positive, DEP said, but less than 0.5 percent of drill cuttings did so in 2012, and the levels were not harmful.
DEP said it will conduct the study in conjunction with the Pittsburgh-area offices of Perma-Fix Environmental Services Inc., and will make the study plan available for an external academic peer review. The study proposal is available on the DEP website.