Effect of microorganisms on the plutonium oxidation states

Particular microbes from substrates at the low-level radioactive waste repository in the Ignalina NPP territory were exposed to 239Pu (IV) at low pH under aerobic conditions. Pu(III) and Pu(IV) were separated and quantitatively evaluated using the modified anion exchange method and alpha spectrometry. Tested bacteria Bacillus mycoides and Serratia marcescens were more effective in Pu reduction than Rhodococcus fascians. Fungi Paecillomyces lilacinus and Absidia spinosa var. spinosa as well as bacterium Rhodococcus fascians did not alter the plutonium oxidation state.

► Particular microbes from low-level radioactive waste repository were exposed to Pu (IV).
► Some tested bacteria induced slight Pu (IV) reduction at low pH under aerobic conditions.
► Tested fungi did not show peculiarities to alter Pu oxidation state.
► The modified radiochemical method was applied to differentiate Pu oxidation states.