Uptake of 137Cs and 60Co by bryophytes and lichens

Sustainable ecosystems much depend on bioaccumulation processes. This study was dedicated to the role of bryophytes. Laboratory experiments showed that the 60Co2+ uptake by terrestrial mosses D. scoparium, P. commune and lichen H. physodes from water solution is a fast process, typical for ion exchange reactions. Equilibrium at 20°C was reached within 2 hours, with prevailing proportion of cobalt localized extracellularly. In the case of mosses, higher proportion of 60Co was found in brown tissue than in green tissue. The 137Cs+ uptake by lichen H. physodes is a two-phase process: the rapid phase of ion exchanges, followed by the slow phase, typical for active transport across biological membranes. Obtained data can serve for prediction of sorption processes of 137Cs and 60Co contamination in the case of their escape from nuclear equipment in a water-soluble form into the moss and lichen vegetation.