Transplanted Epiphytic Lichens as Biomonitors of Air-Contamination by Natural Radionuclides Around the Žirovski VRH Uranium Mine, Slovenia
AbstractSamples of Hypogymnia physodes were transplanted to the environment of the former uranium mine at Žirovski vrh, Slovenia for two exposure experiments. The levels of the long-lived radionuclides, 238U, 226Ra and 210Pb in lichen material were measured after 4 and 7 months in the first experiment, and 4, 8 and 12 months in the second, and compared with the levels in lichens growing in-situ from the same sampling locations. They were also compared with the nuclide levels found in air particulates by gamma spectrometry obtained at the regular site monitoring stations. The results showed that each of the radionuclides had its own distribution pattern in this environment. The highest 226Ra levels were found in lichens in the near vicinity of the dry-tailings pile, while U concentrations were high in the valley of the confluence of the Todraščica and Brebovščica streams close to the former yellow-cake production plant in Todraž, and then decreased downstream. 210Pb was the most uniformly distributed radionuclide and exhibited the highest level. The results also confirm that active biomonitoring with transplanted lichens can be a useful and cheap supplement to instrumental air pollution monitoring.