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The behaviour of technetium during microbial reduction in amended soils from Dounreay, UK [An article from: Science of the Total Environment, The]
Book Details
Author(s)J.D.C. Begg, I.T. Burke, K. Morris
PublisherElsevier
ISBN / ASINB000PDSOYQ
ISBN-13978B000PDSOY2
MarketplaceGermany 🇩🇪
Description
This digital document is a journal article from Science of the Total Environment, The, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Radioactive technetium-99 forms during nuclear fission and has been found as a contaminant at sites where nuclear wastes have been processed or stored. Here we describe results from microcosm experiments containing soil samples representative of the UKAEA site at Dounreay to examine the effect of varying solution chemistry on the fate of technetium during microbial reduction. Analysis of a suite of stable element redox indicators demonstrated that microbial activity occurred in a range of microcosm experiments including unamended Dounreay sediments, carbonate buffered sediments, and microcosms amended with ethylenediaminetetraacetic acid (EDTA) a complexing ligand used in nuclear fuel cycle operations. During the development of anoxia mediated by indigenous microbial populations, TcO"4^- was removed from solution in experiments. In all cases, the removal of TcO"4^- from solution occurred during active microbial Fe(III)-reduction when Fe(II) was growing into the microcosms. Tc removal was most likely via reduction of TcO"4^- to poorly soluble Tc(IV) which is retained on the sediments. The potential stability of Tc associated with the soil to remobilisation via complexation with EDTA was examined as reduced Tc-labelled sediments were contacted with a de-oxygenated EDTA solution. No remobilisation of Tc(IV) in the presence of EDTA was observed.
Description:
Radioactive technetium-99 forms during nuclear fission and has been found as a contaminant at sites where nuclear wastes have been processed or stored. Here we describe results from microcosm experiments containing soil samples representative of the UKAEA site at Dounreay to examine the effect of varying solution chemistry on the fate of technetium during microbial reduction. Analysis of a suite of stable element redox indicators demonstrated that microbial activity occurred in a range of microcosm experiments including unamended Dounreay sediments, carbonate buffered sediments, and microcosms amended with ethylenediaminetetraacetic acid (EDTA) a complexing ligand used in nuclear fuel cycle operations. During the development of anoxia mediated by indigenous microbial populations, TcO"4^- was removed from solution in experiments. In all cases, the removal of TcO"4^- from solution occurred during active microbial Fe(III)-reduction when Fe(II) was growing into the microcosms. Tc removal was most likely via reduction of TcO"4^- to poorly soluble Tc(IV) which is retained on the sediments. The potential stability of Tc associated with the soil to remobilisation via complexation with EDTA was examined as reduced Tc-labelled sediments were contacted with a de-oxygenated EDTA solution. No remobilisation of Tc(IV) in the presence of EDTA was observed.
