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.
The study included an examination of radon levels in natural gas to ensure that public health and the environment continue to be protected. The findings showed that there is limited potential for radiation exposure to the public and workers from the development, completion, production, transmission, processing, storage and end use of natural gas.
The authors did say, however, that there are potential radiological environmental impacts from fluids if spilled.
"Radium should be added to the Pennsylvania spill protocol to ensure cleanups are adequately characterized," the study said. "There are also site-specific circumstances and situations where the use of personal protective equipment by workers or other controls should be evaluated."
The research suggested that all facilities in Pennsylvania accepting oil and gas waste should be studied to determine if any areas require remediation. The authors said if "elevated radiological impacts are found, the development of radiological discharge limitations and spill policies should be considered."
Filter cake from facilities treating oil and gas waste could have a radiological environmental impact if spilled, the study concluded. The authors suggested that disposal protocols should be reviewed to ensure the safety of long-term disposal.
"While the recommendations for future actions contained in the report call for additional studies and efforts," said DEP Secretary for Waste, Air, Radiation and Remediation Vince Brisini, "we now have data to inform the management of natural gas resources and resultant wastes for environmental and health protection."