[en] The uptake of radioactive cadmium and mercury by the fresh water alga phormidium fragile was studied at different time intervals. Cadmium was taken up in amounts significantly greater than mercury and although the rate of uptake of both metals was more or less constant, the bound fraction of cadmium showed a continuous increase. It has also been found that cadmium is more readily released from the algal cells than mercury. Chromatographic analysis of the organic soluble fractions for both metals, the R values as well as their percentages of occurrence are presented and discussed.3 tab