PARENT SESSION
PW7 - Biotransformation / Metabolisms / Degradation
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P797) Effects of Copper on Sulfidogenesis in Metal-Contaminated and Metal-Free Sediments.
Jin, Song*,1, Drever, James2, Brown, Terry1, Colberg, Patricia3, 1 Western Research Institute, Laramie, Wyoming, USA2 Department of Geology and Geography, University of Wyoming, Laramie, Wyoming, USA3 Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
ABSTRACT- The effects of copper on bacterial sulfate reduction in freshwater sediments were examined. Sulfate-reducing bacterial consortia were enriched from both a metal-free and a metal-contaminated sediment. At 0.8 ppm copper, no inhibitory effects on sulfate reduction were observed in either consortium type. At 8.0 ppm copper, activity in the metal-free consortium was significantly inhibited, as evidenced by a delay in and decreased rate of sulfate reduction; sulfidogenesis in the metal-contaminated consortia was apparently unaffected. When the dissolved Cu concentration was 30 ppm, sulfidogenic activity in the metal-free consortium was completely inhibited; the rate of sulfate reduction temporarily decreased in the metal-contaminated enrichments, but recovered after a short time. In the active microcosms, copper was precipitated as CuS. The results of this study suggest that sulfate-reducing bacteria from metal-contaminated environments have a markedly higher metal-tolerance than those from metal-free environments, which is likely due to the selective effects of metal exposure on the microbial community. The most significant inference from this work is that metal-sulfide formation alone may not account for the difference in metal tolerance observed between metal-free and metal-contaminated sediments.
Key words: Metals, Sulfate Reducing Bacteria, Sulfidogenesis, Copper