Airborne radionuclides in mosses collected at different latitudes

Terrestrial mosses are a promising medium for investigation and monitoring of airborne radionuclide depositions due to their widespread occurrence, ease of sampling, and the possibility of high-resolution gamma spectrometry measurements without preparatory chemical treatment of samples. The overall objective of the present study was to compare 7Be, 210Pb and 137Cs activity concentrations (in Bq/kg) in moss samples collected at two different climate zones: the south of Thailand (7 °N) and in Serbia (∼45 °N) in order to examine deposition of airborne radionuclide in these distant areas. Significant difference of the 210Pb content (almost a factor of 2) in mosses was observed. The mean value of 7Be activity in samples from Serbia was almost 40% higher than activity of those collected in Thailand. Level of 137Cs in Thailand mosses was below the detection limit. It was shown that air transport of water droplets in the area of waterfalls and strong turbulence can deposit U and Th daughter nuclei. -- Highlights: ► Activity of airborne radionuclides was measured in mosses in Serbia and Thailand. ► Concentration of 7Be do not differ significantly (about 40%) at two locations. ► Activity of 210Pb is two times higher in Serbian samples than in Thailand ones. ► In moss samples in Thailand concentration of 137Cs is lower than detectable limit. ► in the waterfall area in Thailand radionuclides can be transported by water droplets