RISK ASSESSMENT OF HUMAN EXPOSURE TO RADIONUCLIDES IN SOIL OF URBAN AREAS (PUBLIC PARKS AND OPEN PLAYGROUNDS) IN KRUSEVAC, SERBIA

Abstract

This study aims to obtain data on terrestrial radioactivity coming from naturally occurring (40K, 226Ra, 232Th, and 238U) and artificial (137Cs) radionuclides in surface soil (0-10 cm) of selected eighteen public-access urban areas in Kruševac city, Serbia, and to assess the corresponding health effects for citizens using those areas for recreational purposes. The specific activities of investigated radionuclides were analyzed using HPGe gamma-ray spectrometry. The mean specific activity of 40K, 226Ra, 232Th, 238U, and 137Cs was found to be 353, 39.8, 38.9, 41.0, and 5.9, respectively, in compliance with their values in other parts of Serbia and neighboring countries reported in similar researches. To evaluate the human health risk associated with radionuclides, conservative exposure assumptions and models recommended by the United States Environmental Protection Agency were employed taking into account three exposure routes: ingestion, inhalation of soil, and external irradiation. The absorbed gamma dose rate in the air due to natural radionuclides in soil was calculated. The calculated indices suggested that the radiation risk arising from natural and artificial radionuclides was not significant. The total excess lifetime cancer based on the 95 % upper confidence limit of the specific activities mean was calculated to be 5.8910-6, lower than the tolerable risk for regulatory purposes (10-4). Among investigated radiation exposure pathways, external exposure was the most contributing one for the health risk. The results obtained for the city’s parks and playgrounds suggested their safe use for recreational purposes from the radioecological point of view.