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Title: Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow

Abstract

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 oxidantmore » the net reduction of Co{sup III}EDTA{sup {minus}} dominated the fate and transport of this species.« less

Authors:
; ;  [1]
  1. Oak Ridge National Lab., TN (United States). Environmental Sciences Div.
Publication Date:
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
696774
DOE Contract Number:  
AC05-96OR22464
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 33; Journal Issue: 17; Other Information: PBD: 1 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; COBALT 60; EDTA; BIODEGRADATION; REMEDIAL ACTION; ENVIRONMENTAL TRANSPORT; LOW-LEVEL RADIOACTIVE WASTES; REDOX REACTIONS; GEOCHEMISTRY

Citation Formats

Brooks, S.C., Carroll, S.L., and Jardine, P.M. Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow. United States: N. p., 1999. Web. doi:10.1021/es990245f.
Brooks, S.C., Carroll, S.L., & Jardine, P.M. Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow. United States. doi:10.1021/es990245f.
Brooks, S.C., Carroll, S.L., and Jardine, P.M. Wed . "Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow". United States. doi:10.1021/es990245f.
@article{osti_696774,
title = {Sustained bacterial reduction of Co{sup III}EDTA{sup {minus}} in the presence of competing geochemical oxidation during dynamic flow},
author = {Brooks, S.C. and Carroll, S.L. and Jardine, P.M.},
abstractNote = {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.},
doi = {10.1021/es990245f},
journal = {Environmental Science and Technology},
number = 17,
volume = 33,
place = {United States},
year = {1999},
month = {9}
}