The Cancer Risk Associated with Residential Exposure to Soil Containing Radioactive Coal Combustion Residuals

Abstract

Coal combustion residuals (CCRs) are composed of various constituents, including radioactive materials. The objective of this study was to utilize methodology on radionuclide risk assessment from the Environmental Protection Agency (EPA) to estimate the potential cancer risks associated with residential exposure to CCR-containing soil. We evaluated potential radionuclide exposure via soil ingestion, inhalation of soil particulates, and external exposure to ionizing radiation using published CCR radioactivity values for Th, Ra, U, and Ra from the Appalachia, Illinois, and Powder River coal basins. Mean and upper-bound cancer risks were estimated individually for each radionuclide, exposure pathway, and coal basin. For each radionuclide at each coal basin, external exposure to ionizing radiation contributed the greatest to the overall risk estimate, followed by incidental ingestion of soil and inhalation of soil particulates. The mean cancer risks by route of exposure were 2.01 × 10 (ingestion), 6.80 × 10 (inhalation), and 3.66 × 10 (external), while the upper bound cancer risks were 3.70 × 10 (ingestion), 1.18 × 10 (inhalation), and 6.15 × 10 (external), using summed radionuclide-specific data from all locations. The upper bound cancer risk from all routes of exposure was 6.52 × 10 . These estimated cancer risks were within the EPA's acceptable cancer risk range of 1 × 10 to 1 × 10 . If the CCR radioactivity values used in this analysis are generally representative of CCR waste streams, then our findings suggest that CCRs would not be expected to pose a significant radiological risk to residents living in areas where contact with CCR-containing soils might occur.

Risk assessment of human exposure to radionuclides in soil of urban areas (public parks and open playgrounds) in Krusevac, Serbia

“…Slope fac tors for 226 Ra, 232 Th, 238 U, and 137 Cs were cho sen to ac count for short-lived de cay prod ucts and in clude the par ent radionuclide, as well as ingrowth of daugh ter iso topes out to 100 years (+ P des ig na tion in tab. 3), as sum ing secu lar equi lib rium with the par ent nu clide [5].…”

“…This model has been proved as a pow er ful tool for as sess ing hu man health risk and iden ti fy ing the ex po sure path ways of most con cern due to dif fer ent chem i cals, mostly heavy met als, per sis tent or ganic pol lut ants, polycyclic ar o matic hy dro car bons, etc., pres ent in diverse en vi ron men tal me dia [4]. Al though the meth od ology in cludes radionuclide risk as sess ment tools, it has been rarely used to char ac ter ize hu man health risks result ing from a po ten tial ex po sure to radionuclides via the ex po sure path ways de ter mined ap pro pri ate for the source area [5,6].…”