title: Plutonium interaction studies with the Mont Terri Opalinus Clay isolate Sporomusa sp. MT-2.99: changes in the plutonium speciation by solvent extractions.
abstract: Since plutonium could be released from nuclear waste disposal sites, the exploration of the complex interaction processes between plutonium and bacteria is necessary for an improved understanding of the fate of plutonium in the vicinity of such a nuclear waste disposal site. In this basic study, the interaction of plutonium with cells of the bacterium, Sporomusa sp. MT-2.99, isolated from Mont Terri Opalinus Clay, was investigated anaerobically (in 0.1 M NaClO4) with or without adding Na-pyruvate as an electron donor. The cells displayed a strong pH-dependent affinity for Pu. In the absence of Na-pyruvate, a strong enrichment of stable Pu(V) in the supernatants was discovered, whereas Pu(IV) polymers dominated the Pu oxidation state distribution on the biomass at pH 6.1. A pH-dependent enrichment of the lower Pu oxidation states (e.g., Pu(III) at pH 6.1 which is considered to be more mobile than Pu(IV) formed at pH 4) was observed in the presence of up to 10 mM Na-pyruvate. In all cases, the presence of bacterial cells enhanced removal of Pu from solution and accelerated Pu interaction reactions, e.g., biosorption and bioreduction.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany. h.moll@hzdr.de.
authors.forename: Henry
authors.initials: H
authors.lastname: Moll
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cherkouk
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Bok
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, Bautzner Landstrasse 400, 01328, Dresden, Germany.
authors.forename: Gert
authors.initials: G
authors.lastname: Bernhard
mesh_terms: D000538:Aluminum Silicates; D000077215:Clay; D010084:Oxidation-Reduction; D011005:Plutonium; D012997:Solvents; D014875:Water Pollutants, Radioactive
chemical_list: D000538:Aluminum Silicates; D012997:Solvents; D014875:Water Pollutants, Radioactive; D011005:Plutonium; D000077215:Clay
keywords: Bacteria; Bioreduction; Biosorption; Plutonium; Solvent extractions; Sporomusa sp.