Organic cesium carrier(s) in lichen

Most of the radiocesium was extracted from the lichen Cetraria islandica in aqueous medium (91.5%) without significant destruction of the lichen itself. Fractional precipitation with ethanol demonstrated that essential biomacromolecules were contaminated slightly with cesium. Using thin-layer and column chromatography at least three cesium-containing compounds were found in the residual solution. Two of them absorbed light at 270 nm. Further analysis of the main peak demonstrated instability resulting in newly formed compounds with smaller molecular masses. From this it was concluded that a significant amount of radiocesium in lichen is associated with organic molecules which tend to decompose upon isolation.