The natural depuration rate of 137Cs radionuclides in a lichen and moss species

Caesium-137 concentrations in lichen and moss samples have been studied for calculations of natural depuration rates. The lichen and moss species were collected from the same trees in western and eastern Black Sea region during the periods of 1987-1992 and 1990-1993, respectively. The natural depuration rates are estimated at biological half-lives. The pattern of depuration results represented by a single component for each non-vascular plant. The biological half-lives of 137Cs in a lichen and moss samples (Xanthoria parietina and Leucodon immersus) are estimated to be 5.86 and 10.9 months, respectively. This work set supports the view that radioactivity monitoring in lichens can be a more useful monitor than mosses to determine the lasting effect of radioactive fallout. (author)