Bacteria to decontaminate water polluted by radioisotopes?

While studying carbonate rocks forming in the crater lakes of volcanoes in Mexico, we discovered a new photosynthetic bacterial species precipitating amorphous intracellular carbonate granules. This bacterium belongs to the cyanobacteria phylum and we have named it Gloeomargarita lithophora. We incubated these bacteria in their Ca-rich culture medium, to which we added either the isotope ²²⁶Ra or the isotope ⁹⁰Sr. We tested different concentrations, up to a million times lower than that of Ca. By measuring the doses of gamma and beta radiation emitted respectively by ²²⁶Ra and ⁹⁰Sr in the soluble fraction and in the cellular fraction of the cultures, we showed that more than 99% of the radionuclides were trapped by the cells of this species in less than an hour, despite the large excess of Ca