Sustained bacterial reduction of Co[sup III]EDTA[sup [minus]] in the presence of competing geochemical oxidation during dynamic flow

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es990245f· OSTI ID:5923996

Brooks, S C; Carroll, S L; Jardine, P M ^[1]

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1. Oak Ridge National Lab., TN (United States). Environmental Sciences Div.

Radionuclides and metals can be mobilized by chelating agents typically present in low-level radioactive liquid wastes. [[sup 60]Co]EDTA in the form [sup 60]Co[sup III]EDTA[sup [minus]] represents a highly stable and mobile form of this radionuclide. By contract, the reduced form of this metal-ligand complex, [sup 60]Co[sup II]EDTA[sup 2[minus]], is much less stable and less mobile. There is an increasing awareness that dissimilatory metal-reducing bacteria (DMRB) can be used to mediate redox transformations of metals and radionuclides whose stability and mobility are governed by their oxidation state. The authors conducted a series of column experiments to provide an improved understanding of Co[sup III]EDTA[sup [minus]] reduction by the facultative anaerobe Shewanella alga BrY (BrY). Experiments were conducted under growth conditions using lactate a carbon and energy source. They were able to demonstrate the sustained reduction of Co[sup III]EDTA[sup [minus]] in column flow experiments with the desired result that a less stable, less mobile product was formed. The amount of reduction varied directly with the fluid residence time in the columns. In the presence of a suitable mineral sorbent [Fe(OH)[sub 3]], Co-EDTA transport was delayed as a direct consequence of the bacterial reduction reaction. Even in the presence of a strong mineral oxidant the net reduction of Co[sup III]EDTA[sup [minus]] dominated the fate and transport of this species.

• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 5923996
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Vol. 33:17; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540230* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIODEGRADATION
CARBOXYLIC ACIDS
CHELATING AGENTS
CHEMICAL REACTIONS
CHEMISTRY
COBALT 60
COBALT ISOTOPES
DECOMPOSITION
EDTA
ENVIRONMENTAL TRANSPORT
GEOCHEMISTRY
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LOW-LEVEL RADIOACTIVE WASTES
MASS TRANSFER
MATERIALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
RADIOISOTOPES
REDOX REACTIONS
REMEDIAL ACTION
WASTES
YEARS LIVING RADIOISOT