Radium in Aquatic Food Chains: Radium Uptake by Fresh Water Algae

Abstract

Accumulation of226 Ra was studied in four species of green algae; Ankistrodesmus falcatus var. acicularis, Chlorella vulgaris, Coelastrum cambricum, Chlamydomonas simplex and two species of blue-green algae, Microcystis pulverea and Anacystis nidulans. Algae were cultivated in inorganic culture. Radium was added in amounts of 1 μCi/l., 0.1 μCi/l. and 0.01 μCi/l. After 14 days the amount of radium in the medium in dead and living algal cells, and in washes from the algae, was determined at intervals using a liquid scintillation counter. There were two characteristic types of response to radium. The first was shown by Ankistrodesmus falcatus var. acicularis and Coelastrum cambricum. From 50 to 80% of the radium was absorbed within the cells and the amount absorbed was proportional to the length of exposure. In the second type of response, typical of the other four species of algae, radium was mostly adsorbed on the cell surface (25-50%) and only 1-8% was present within the cells. The highest accumulative fa...