Human Health Risk Assessment of NORM Exposure from Coal Ash

Cardno ChemRisk recently presented an analysis examining the cancer risk associated with residential exposure to radioactive components in soils containing coal combustion residuals (CCRs) at the 2017 Society of Toxicology (SOT) annual conference. CCRs are waste products created as a result of burning coal at power plants during the production of electricity, and are one of the largest industrial waste streams generated in the United States. In 2012, approximately 40 percent of CCRs were beneficially used (i.e. concrete and wallboard), while the remaining 60 percent were disposed of in surface impoundments and landfills. Coal and CCRs are composed of various constituents, including naturally occurring radioactive materials. For our research, Cardno ChemRisk scientists utilized reported mean and upper bound isotope-specific radioactivity values to calculate the potential human health cancer risks associated with residential exposure to CCR-containing soil via ingestion of soil, inhalation of particulates emitted from soil, and external exposure to ionizing radiation. The mean cancer risk was 7 x 10-9, and the upper bound cancer risk was 1 x 10-8. Both the mean and upper bound calculated cancer risks were below the Environmental Protection Agency's (EPA) acceptable risk threshold of 1 x 10-6 to 1 x 10-4. These findings suggest that residents living on lots with ground soil containing CCRs are not at an increased risk of cancer due to the presence of naturally occurring radioactive components in CCRs under the exposure parameters analyzed.

If you would like to learn more about Cardno ChemRisk's experience with coal ash, please contact Paul Scott