Spatial distribution of 7Be and 137Cs measured with the use of biomonitors

An attempt to establish a spatial distribution of the atmospheric deposition of the 7Be was done using terrestrial mosses as medium. The levels of naturally present radionuclide 7Be (and 40K, 137Cs, 212Pb and 214Bi as well) were measured in 217 moss samples collected from the entire territory of the Republic of Serbia. Measurements were performed by a well-type NaI detector. Measurable values of activity concentrations of 7Be (up to the 666 Bq kg−1) were detected in all moss samples. The measured minimal and maximal activity concentration values of 7Be were found to differ ninefold. It is much higher than the difference between minimal and maximal 7Be activity measured in surface air measured in 34 stations in EU. It was obtained that the spatial distribution of 7Be is non-uniform shoving small isolated islands having significantly higher (or lower) activity concentrations than neighboring area. Prominent local differences in activity concentration cannot be observed in spatial distribution of 137Cs which was exposed to different environmental influences after deposition during three decades.