Human health risk assessment due to natural radionuclides in soil affected by coal combustion: A case study from the surroundings of the largest thermoelectric power plant in Serbia

Abstract

The study was aimed at assessing the human health risk potentially induced by the presence of natural radionuclides and their decay chain daughters in the soil of the area impacted by coal combustion in the largest Serbian coal-based thermoelectric power plant “Nikola Tesla A”. The total intakes of 40K, 226Ra and 232Th for residents in the study area through ingestion and inhalation of soil particles, ingestion of fruits and vegetables, as well as external irradiation, were evaluated, and the derived carcinogenic risk was characterized applying methodology of the US EPA based on minimal, median and maximal values of specific activities of mentioned radionuclides in soil measured by gamma-ray spectroscopy. The total excess lifetime cancer risk was in the range (1.70–3.91) × 10-4, which is higher than the established target value of 10-4. Ingestion of homegrown produce was identified as an exposure route of the most concern, followed by external irradiation originating from radionuclides investigated. The risk posed by inhalation of soil particles found to be negligible, while direct ingestion of soil resulted with total risk slightly above the US EPA screening level of 10-6. The results of the study will contribute to a better understanding of the radiation hazard coming from natural radioactivity in the Serbian region that is most affected by operation of coal-fired thermoelectric power plant.

Cilj istraživanja je procena rizika po zdravlje ljudi usled prisustva prirodnih radionuklida i njihovih potomaka u zemljištu na prostoru koji je pod uticajem sagorevanja uglja u najvećoj termoelektrani u Srbiji „Nikola Tesla A“. Procenjeni su ukupni unosi 40K, 226Ra i 232Th za stanovnike istraživanog prostora usled ingestije i inhalacije zemljišta, ingestije voća i povrća gajenog na istraživanom prostoru i spoljnjeg izlaganja jonizujućim zračenjima. Procena rizika od kancerogeneze tokom životnog veka je izvršena koristeći metodologiju Agencije za zaštitu životne sredine SAD (US EPA), polazeći od minimalnih, maksimalnih i vrednosti medijane za specifične aktivnosti analiziranih radionuklida čije su specifične aktivnosti određene spektrometrijom gama zračenja. Ukupni rizik od kancerogeneze tokom životnog veka je bio u opsegu (1.70–3.91) × 10-4 što premašuje gornju graničnu vrednosti rizika od 10-4 prema US EPA. Ingestija voća i povrća gajenih na istraživanom prostoru je identifikovana kao put izlaganja sa najvećim rizikom, a sledi ga spoljašnje ozračivanje od stane analiziranih radionuklida. Rizik izazvan inhalacijom zemljišnih čestica je bio zanemarljiv, dok je procenjeni rizik usled direktne ingestije zemljišta iznosio nešto više od 10-6, što je donja granica tolerantnog rizika prema US EPA. Rezultati istraživanja doprinose boljem razumevanju radiološkog rizika koji potiče od prirodne radioaktivnosti u regionu Srbije koji je najugroženiji radom termoelektrana na ugalj.