Assessment of gamma dose rates from terrestrial exposure in Serbia and Montenegro

Abstract

The gamma dose rates due to naturally occuring terrestrial radionuclides (Ra-226, Th-232 and K-40) were calculated based on their activities in soil samples, determined by gamma-ray spectrometry. A total of 140 soil samples from 21 different regions of Serbia and Montenegro were collected. The gamma dose rates ranged from 7.40 to 29.7 nGy h(-1) for Ra-226, from 12.9 to 46.5 nGy h(-1) for Th-232 and from 12.5 to 37.1 nGy h(-1) for K-40. The total absorbed gamma dose rate due to these radionuclides varied from 34.5 to 97.6 nGy h(-1) with mean of 66.8 nGy h(-1). Assuming a 20% occupancy factor, the corresponding annual effective dose varied from 4.23 x 10(-5) to 11.9 x 10(-5) Sv with mean of 8.19 x 10(-5) Sv, i.e. the dose was lower than world wide average value. According to the values of external hazard index (mean: 0.39) obtained in this study, the radiation hazard was found to be insignificant for population living in the investigated area.