Method for evaluating the impact of radioactivity on phytoplankton

The target alga is Chlamydomonous reinhardii, a common green flagellate that is amenable to growth in the laboratory. The model radionuclide is cesium-137, an important constituent of the radioactive liquid effluents from nuclear power plants. The organisms are grown in a chemostat, which consists of four growth chambers. The chemostate allow algae to be maintained in their log growth phase while various environmental parameters are manipulated. It was found that the cesium-137 concentration factors are controlled by the phosphate concentration, the sodium concentration, and the algal biomass. Temperature, algal reproduction rate, potassium concentration, and chloride concentration have no effect on the observed concentration factors. The cesium concentration factor ranges from 115 to 586 on a dry weight basis under the various environmental conditions studied. 23 refs