Current radioactive fallout contamination along a trans-European gradient assessed using terricolous lichens.

Lichens are considered to be good indicators of contamination of the terrestrial environment. In this study, we investigated the level of 137Cs and 4 K accumulated by Cladonia arbuscula and Stereocaulon alpinum along a longitudinal gradient from northern Norway, across Sweden to southern Poland. Additionally, we compared isotope contents between the selected lichen species, and investigated the correlation of the 137Cs content accumulated by C. arbuscula with 137Cs fallout after the Chernobyl disaster. The activity of 137Cs varied from 3.58 Bq kg-1 to 559 Bq kg-1 for S. alpinum, and from 1.18 Bq kg-1 to 130 Bq kg-1 for C. arbuscula. The activity of 4 K ranged from 114 Bq kg-1 to 341 Bq kg-1 for S. alpinum and from 27.2 Bq kg-1 to 314 Bq kg-1 for C. arbuscula. The 137Cs content did not differ between C. arbuscula and S. alpinum; however, the difference between species was significant for 4 K accumulation. The activity of 137Cs in C. arbuscula was significantly correlated with deposition from 1986. Based on our findings we created a spatial map of 137Cs activity in lichens measured 30 years after the event that was the primary source of this isotope. We showed that C. arbuscula can be used to assess contamination and create interpolation maps of radionuclide deposition, even if the primary deposition took place many years ago.

Impact of distance from the glacier on the content of 137Cs and 90Sr in the lichen Cetrariella delisei.

The Arctic region is substantially a pristine area, but this unique part of the globe has also been contaminated by anthropogenic radioactive nuclides, and now there is still measurable activity of anthropogenic isotopes, even though more than 50 years have passed since the main source. Radionuclides in the Arctic, especially 90Sr have seldom been studied despite their considerable environmental importance. This manuscript covers the results of 90Sr and 137Cs measurements in soil and lichen Cetrariella delisei collected from the Svalbard in 2012. In both lichen thalli and surface soils high activities of 90Sr and 137Cs were recorded and ranged between 3.69 and 28.1 Bq kg-1 90Sr and 5.38-280.1 Bq kg-1137Cs in thalli and between 4.53 and 12.78 Bq kg-1dw 90Sr and 60.6-426.1 Bq kg-1dw 137Cs in surface soil layer. The activity of 90Sr and 137Cs in lichen thalli was influenced by distance from the glacier. This showed that during radionuclide biomonitoring of particular area with the use of lichens, it is important to take into account influence of environmental variability on radionuclides contents.