Radioactive Levels and Human Health Effects in a Dumpsite on Ulaanbaatar City, Mongolia

Most of the solid waste from Ulaanbaatar city during the cold season is ash from the partial combustion of coal. Burial of the ashes with other solid wastes has affected radioactive isotope levels in the soil. We investigated levels of radionuclides Ra-226, Th-232, K-40, and Cs-137 in soil samples collected from the Naran Enger landfill using a gamma-ray spectrometer. The radioactivity of naturally occurring radionuclides in the soil samples was highest underneath the buried waste zone, and lowest around the ger areas and at the initial reference location. In the buried zone, activity of K-40 isotope was two times higher than the world average. The results showed that radium equivalent activity (Ra-eq) ranged between 69 and 183 Bq.kg(-1), and the Raeq of ash was 338.3 Bq.kg(-1). The external and internal hazard indexes were 0.2 and 0.5, respectively. From the Ra-eq, H-in, H-ex, D-out, and D-in values, we calculated lifetime cancer risk and found the risk to be (0.8-1.58) x 10(-3). Current values of Raeq and hazard indices were found to be within the recommended limits. (C) 2022 American Society of Civil Engineers.