No abstract

There is a scarcity of data on transfer of both natural and anthropogenic radionuclides to detritivorous invertebrates for use in the assessment of radiation exposure. Although mosses and lichens have been extensively used in biomonitoring programs, the data on transfer of radionuclides to these species are limited, particularly for natural radionuclides. To enhance the available data, activity concentrations of (137)Cs, (226)Ra and (228)Ra were measured in ants, mosses and lichens and corresponding undisturbed soil collected from semi-natural ecosystems in Serbia and Montenegro and biota/soil concentration ratios (CR) calculated. Since the majority of internal dose to biota is expected to come from (40)K, the activity concentrations of this radionuclide were also determined. The mean CR values for (137)Cs, (226)Ra and (228)Ra in ants analyzed in this study were found to be 0.02, 0.06 and 0.02, respectively. The mean CR values of radionuclides in mosses were found to be 2.84 for (137)Cs, 0.19 for (226)Ra and 0.16 for (228)Ra, while those in lichens were found to be 1.08 for (137)Cs, 0.15 for (226)Ra and 0.13 for (228)Ra. The CR values obtained in this study were compared with default CR values used in the ERICA Tool database and also with those reported in other studies.

The activity concentrations of (226)Ra, (232)Th and (40)K in 178 samples from 52 locations of the territory of Belgrade, the capital of Serbia, were determined by gamma-ray spectrometry. Based on the results obtained, the values of absorbed gamma dose rate at 1 m above the ground, radium equivalent activity, external hazard index, annual effective dose, annual gonadal dose and excess lifetime cancer risk were calculated. The results of the present study were compared with values reported worldwide and also with internationally recommended values. The total absorbed dose rate varied between 24.7 and 89.6 nGy h(-1) with a mean of 60.5 nGy h(-1), which is close to the world average value. Since all estimated radiological impact assessment factors were lower than the recommended values there seems to be no radiological health hazard for the population living in the investigated area.