Population doses from terrestrial gamma exposure in Belgrade (Serbia) and their relation to geological setting

Abstract

Terrestrial radiation exposure emitted from naturally occurring radionuclides, such as 40K and radionuclides from the 238U and 232Th series and their decay products represent the main external source of irradation to human body. The purpose of this study was to provide the assessment of the doses from terrestrial exposure of population in Belgrade. The gamma dose rate, annual effective doses and external hazard indexes due to terrestrial natural occurring radionuclides (226Ra, 232Th, 40K) were calculated based on their activities in soil samples in Belgrade determined by gamma-ray spectrometry. The mean value of the total absorbed gamma dose rate outdoors due to terrestrial radionuclides for Belgrade was 59 nGy/h which is close to the worldwide average value (58 nGy/h). The values of the gamma dose rate varied among sampling locations as a consequence of different geological formations in the investigated area. The mean value of annual effective dose of 73 Sv was significantly lower than the maximum allowed dose of 1 mSv for the population and was consistent with the worldwide average value. The mean value of external hazard index was found to be 0.28. The results of this assessment study pointed out that there is no significant radiation risk to the population of Belgrade due to terrestrial exposure to radiation from natural sources outdoors.