Subsurface interactions of actinide species and microorganisms: Implications for the bioremediation of actinide-organic mixtures

Association of uranyl with the cell wall of Pseudomonas fluorescens inhibits metabolism

“…Only two hydroxide species are considered because, the inhibitory species is likely to be a cation due to its binding to the negatively charged surface of cells. Banaszak et al (1999) concluded that a uranylcitrate complex was the toxic species. The design of our experiments does not allow a definitive conclusion on the toxicity of the uranyl-citrate complex.…”

“…The authors concluded that the persistence of citrate stemmed from the inability of the cells to transport the uranyl-citrate complex across the cell membrane. Another study by Banaszak et al (1999) suggests that the uranyl-citrate complex itself is toxic to P. fluorescens. Finally, Huang et al (1998) show that there is incomplete citrate (0.55 mmol/L) degradation by a mixed cell culture in the presence of uranyl (0.42 mmol/L) at pH 6.…”

Microbial transformations of plutonium and implications for its mobility

“…An analogous comparison of 239Pu(NOX)4.-and '3sPu(N03)4.-treated soil at the lOuCi/g level showed the same effect, but toxicity at both mass levels was not as pronounced as in the DTPA-treated soils, reflecting the importance of solubility, as well as radiation level, on , , toxicity (Wildung and Garland, 1982). Banaszak et al (1999) (Barnhart et al, 1980). The production of extracellular chelating agents resembling siderophores was observed for Pseudomonas aeruginosa grown in the presence of uranium and thorium (Premuzic et al, 1985).…”

Technical assistance to Ohio closure sites; Technologies to address leachate from the on-site disposal facility at Fernald Environmental Management Project, Ohio

“…It has also been demonstrated that a number of metals can also be transformed into less soluble forms by the same mechanism, e.g., chromium, uranium (Banaszak et al, 1999). This type of microbial activity requires strongly anaerobic conditions and the presence of anaerobic microorganisms possessing reductive capability.…”

“…It may be possible to use the uranium surface water limit of 530 ppb for acceptance and justification for use of this type of system. Constructed wetlands are a mature technology for tertiary and even secondary treatment of municipal and industrial effluents and have been tested on a small scale for effluents with actinides; however, the technical assistance Team was not aware of any long-term or large-scale applications that would provide the necessary data to verify the efficacy and overall risk (Banaszak et al, 1999).…”