Naturally attracted radioactive isotopes
The Pennsylvania Department of Environmental Protection (DEP) released the results of what it believes to be "the most comprehensive radiological study of the oil and gas industry ever conducted," finding in most cases that the radioactivity of shale rock is of little danger to the public and workers.
The authors cautioned, however, that more studies will need to be conducted on the topic.
The DEP began studying radioactivity levels in flowback waters, treatment solids and drill cuttings, as well as transportation, storage and disposal of drilling wastes in January 2013 at the direction of Gov. Tom Corbett.
Compared to other rock forms, shale contains high amounts of organic materials, which naturally attracted radioactive isotopes millions of years ago when the sediment was deposited. A debate has raged in the Appalachian Basin and other parts of the country about how the horizontal hydraulic fracturing process enhances those materials and whether they pose a threat to workers when they come to the surface or to the general public when things such as drill cuttings are disposed of (see Shale Daily, Jan. 13, 2014).
The DEP's peer-reviewed study found that there is "little potential for radiation exposure to workers and the public at facilities that treat oil and gas wastes." The agency also said there is little risk of radiation exposure to the public and workers from landfills receiving waste from the oil and gas industry.