Microbially Promoted Solubilization of Steel Corrosion Products and Fate of Associated Actinides
This project will probe fundamental scientific issues regarding a microbial process with potential for decontaminating corroding metal surfaces. We hypothesize that dissimilatory iron-reducing bacteria (DIRB), via anaerobic respiration, can quantitatively dissolve amorphous and crystalline iron oxides and thereby release oxide-associated radionuclide contaminants. Associated actinides will be sorbed by cell surfaces or precipitated within biofilms that can be removed and recovered by enzymatic digestion of microbial attachment factors. This environmentally benign, enzymatic process avoids the use of hazardous or toxic chemicals, minimizes the volume and toxicity of secondary wastes, and could be applied in situ. Although an increasing body of scientific literature supports this working hypothesis, a basic understanding is needed of the biological and chemical processes that impact (1) attachment and detachment of iron reducing bacteria to oxide surfaces; (2) the rate, extent, and products of iron reduction; and (3) the fate of radionuclides following enzymatic reduction of corroding steel (which is needed to evaluate and develop effective biological approaches for decontamination of aging metallic structures and piping). The goal of this project is to provide the scientific underpinnings for the development of biologically based approaches for the removal of contaminants from corroding steel surfaces. Specifically, this research will accomplish the following: (1) determine the role of oxide structure, topology, and composition on bacterial attachment and subsequent reductive dissolution of Fe(III) oxide corrosion products that form on stainless and mild steels; (2) identify how soluble electron ''shuttles'' can facilitate the rate and extent of microbial reductive dissolution of iron oxide corrosion products, including surface features and pores inaccessible to bacteria; (3) determine the distributions of radionuclides released during reductive dissolution of oxide films on metal surfaces as a function of aqueous geochemical composition. This project uniquely couples PNNL's expertise in microbial metal reduction and biogeochemistry with Montana State University's Center for Biofilm Engineering's expertise and capabilities in biofilm analysis, engineering, and corrosion. In addition, this research project will take advantage of the capabilities and expertise at PNNL in actinide chemistry and advanced instrumentation for probing the distribution and chemical nature of surface-associated radionuclides and metals associated with the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL).
- Research Organization:
- Pacific Northwest National Laboratory, Richland, WA; Montana State University, Bozeman, Bozeman, Montana; University of New Hampshire, Durham, New Hampshire (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- FG07-98ER62714; FG07-98ER62719
- OSTI ID:
- 831210
- Report Number(s):
- EMSP-64931-1999; R&D Project: EMSP 64931; TRN: US200430%%286
- Resource Relation:
- Other Information: PBD: 1 Jun 1999
- Country of Publication:
- United States
- Language:
- English
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