Chernobyl 137Cs in lichens:: Use of specific activity showing differences in transport routes of Cs and 137Cs

Lichens, sampled around Chernobyl in 1990 and in Slovenia in 1992, were analyzed for radionuclides and elements, including Cs. Data were processed by Monte Carlo aided Target Transformation Factor (MCTTFA). The resulting factors indicate environmental accumulation routes. K-40:K and Pb-210:Ph ratios tested the procedure, showing fully mixed K-40 and K, while for Pb-210 and Ph the expected variability in specific radioactivity was confirmed. Cs-137 showed a large factor-specific variability in Cs-137: Cs ratios. For the 1990 data, MCTTFA singled-out Cs-137 in a separate factor, suggesting that the overall behavior of Cs-137 cannot be derived from that of Cs: source (route)-related specific radioactivity makes that all individual transport-components should be taken into account.