U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993, Water-Resources Investigations Report 94-4015

Bioremediation of Petroleum and Metal Contamination with Dissimilatory Metal Reduction

Abstract

The possibility that the metabolism of dissimilatory metal-reducing microorganisms might be used for removing organic contaminants and metals from contaminated environments was investigated. The Fe(III) chelator, nitrilotriacetic acid (NTA) enhanced the degradation of toluene in petroleum-contaminated aquifer material in which Fe(III) reduction was the terminal electron-accepting process. Addition of Fe(III) oxide containing sediments stimulated toluene degradation in sediments that were originally methanogenic. These results suggest that increasing the availability of Fe(III) may be a useful bioremediation strategy in aquifers that are heavily contaminated with aromatic compounds. Studies on the mechanism for U(VI) reduction by Desulfovibrio vulgaris indicated that cytochrome c₃ is the U(VI) and Cr(VI) reductase. Cytochrome c₃ reduced U(VI) in uranium-contaminated mine drainage and ground water. This finding indicates that it may be possible to genetically engineer microorganisms with enhanced metal-reducing capacity. These studies demonstrate that dissimilatory metal reduction may be a useful mechanism for bioremediating organic and (or) metal contamination in some environments.