Correction to "Sequestration of Radionuclides Radium-226 and Strontium-90 by Cyanobacteria Forming Intracellular Calcium Carbonates".

Ra-226 is a naturally occurring radionuclide with a half-life of 1600 years. In contrast, Sr-90 is a radionuclide of sole anthropogenic origin, produced by nuclear fission reactions and has a half-life of 29 years; each of these radionuclides poses potential threats to human and ecosystem health. Here, the cyanobacterium Gloeomargarita lithophora, capable of forming intracellular amorphous calcium carbonate inclusions, was investigated for its ability to uptake Ra-226 and Sr-90. In BG-11 medium, G. lithophora accumulated 3.9 mu g g(-1) of Ra-226 within 144 h and 47.9 ng g(-1) of Sr-90 within 1 h, corresponding to similar to 99% removal of trace radionuclides. The presence of high-concentration Ca2+ in the background media solution did not inhibit Sr-90 and Ra-226 uptake by G. lithophora. In contrast, dead biomass of G. lithophora accumulated 0.8 mu g g(-1) of Ra-226 and 8.87 ng g(-1) of Sr-90. Moreover, Synechocystis, a nonbiomineralizing cyanobacteria, removed only 14 and 25% of Ra-226 and Sr-90, respectively. This suggested that sequestration of Sr-90 and Ra-226 was not intrinsic to all cyanobacteria but was likely a specific biological trait of G. lithophora related to the formation of intracellular amorphous Ca-carbonates. The unique ability of G. lithophora to uptake Sr-90 and Ra-226 at high rates makes it an attractive candidate for further studies involving bioremediation of these radionuclides.