DEP Analysis Concludes No Radioactivity Danger in Tenmile Creek
An extensive six-month investigation by the Pennsylvania Department of Environmental Protection (DEP) has concluded that there is no indication of any elevated radioactivity in Tenmile Creek in Greene County. The latest DEP study was conducted after concerns were raised about the results of a set of surface water samples taken in the spring of 2014.
DEP’s Bureaus of Radiation Protection and District Mining Operations conducted comprehensive sampling at the same 3 locations where the earlier samples were taken at the Clyde Mine Treatment Facility (CMTF) near Clarksville, Greene County. Additionally, samples were taken at 9 other locations both upstream and downstream of the CMTF. Surface water samples were taken along with samples of sediment, sludge, soil, aquatic vegetation, and fish.
“Our goal was to get a complete picture of any possible radiological contamination,” said John Stefanko, DEP Executive Deputy Secretary for Programs. “The original 2014 samples used a basic methodology that provides a limited sensitivity for naturally occurring radioactive materials. The 2015 samples were analyzed using U. S. Environmental Protection Agency (EPA) approved methodologies for determining radium-226 and radium-228 in water, plants, soil, or fish. The 2015 water samples were taken when the average daily stream flows within the watershed were at near normal flow conditions.”
All water samples were below the EPA drinking water limit of 5 picocuries per liter(pC/L) for radium-226 and radium-228. DEP did not find any indication of accumulated radiation in the sediment, plants, or fish.
One sample, of treatment sludge in a tank at the CMTF, indicated a radioactivity level for radium-228 at 19.539 pCi/L, which is not a level of concern but was a point of interest for DEP. DEP’s Bureau of Mining Programs staff determined that because the treatment facility uses a high-density sludge which recirculates treatment sludge to remove contaminants from water, the radium values would be concentrated. Water exiting the CMTF did not contain a radium level above typical background radiation readings. Although the Department does not believe the radium-228 level is cause for concern, as a matter of public interest it will periodically resample and analyze the CMTF sludge in 2016.
A set of non-radiological water samples was taken simultaneously with the radiological samples to characterize the water flowing into the creek from the CMTF. DEP’s Bureau of Mining Programs staff analyzed the sample results and concluded that the flow of raw and treated mine water was typical mine drainage, consistent with what would originate from a flooded underground coal mine in Southwestern Pennsylvania.
“Ultimately, there were no surprises in the environmental samples we took,” said Stefanko. “The radiological results were in line with expected background radiation readings. The non-radiological samples were consistent with what we regularly see in flooded underground mines in this region.”