Title

Dissimilatory iron reduction causes lead release from iron-oxyhydroxides.

Date of Award

2006

Degree Type

Thesis

Degree Name

M.Sc.

Department

Geology

Keywords

Biogeochemistry.

Rights

CC BY-NC-ND 4.0

Abstract

Iron oxyhydroxides have strong chemical affinities for many trace metals including Pb, in aquatic systems where they often comprise several weight percent of the sediments. During diagenesis, Fe-oxyhydroxides may be reductively dissolved during anaerobic respiration. In freshwater sediments, where sulphate concentrations are low, most Fe reduction is microbially catalyzed. In this enzymatic process termed Dissimilatory Iron Reduction (DIR), Fe (III) minerals are used as terminal electron acceptors coupled to organic matter oxidation. In this study we examine the fate of Pb associated with Fe-oxyhydroxides during DIR in the presence of Shewanella putrefaciens 200R and lactate as the sole electron donor. The extent of Fe reduction, determined from the amount Fe(II) extractible from the mineral slurry by 0.5 mol L -1 HCl, was equivalent for both Pb bearing and pure Fe-oxyhydroxides. In contrast, aqueous Fe(II) concentrations in Pb-bearing Fe-oxyhydroxides reactors were significantly higher than those in reactors without Pb. (Abstract shortened by UMI.) Source: Masters Abstracts International, Volume: 45-01, page: 0252. Thesis (M.Sc.)--University of Windsor (Canada), 2006.