Radium-226 is accumulated in calcium granules in the tissues of the freswater mussel, Velesunio angasi: Support for a metabolic analogue hypothesis

Abstract

Abstract-\. The distribution of226Ra, Ca, Ba and Mg in the tissues of the freshwater mussel, Velesunio angasi, was studied. 2. The concentration of 226Ra is significantly (P < 0.05) and positively correlated with the concentrations of the alkaline earths, Ca, Mg and Ba, in dissected tissues of V. angasi. 3. Alpha track autoradiography, electron microprobe and X-ray analysis, and histochemical studies have shown that 226Ra, Ca, Mg and Ba are co-located predominantly in granular deposits that are dispersed throughout the body of V. angasi. 4. The value of such a co-Iocational study in supporting hypotheses of analogous metabolic behaviour between the non-essential 226Ra and Ca has to be assessed in relation to the functions attributed to calcium granules. 5. Granules may simultaneously accumulate 226Ra and act as a store of exchangeable Ca.