GEOC 17 |
| Michelle V. Nugent1, Kristi Hindle2, David R.S. Lean2, and Danielle Fortin1. (1) Department of Earth Sciences, University of Ottawa, 140 Louis Pasteur, Ottawa, ON K1N 6N5, Canada, (2) Department of Biology, University of Ottawa, 140 Louis Pasteur, Ottawa, ON K1N 6N5, Canada |
| Decommissioning of hydro-dams will increase exposure of sediments to air. Biogeochemical changes, such as oxidation and metal mobilization can occur. The present study was designed to simulate drying and wetting events of sediment cores in order to assess the biogeochemistry of iron and sulfur. Sediment cores were collected from two lakes with different buffering capacities. Dissolved Fe and S concentrations were monitored over 6 months, along with bacterial populations (Fe-, S-oxidizers). Every two weeks, the cores underwent wet/dry cycles with simulated acidic rainwater. Our results showed that the sediments of both lakes buffered the acidic rainwater. Sulfide and iron species (Fe(II), Fe(III)) concentrations decreased over time in the leachate and with depth, except for sulfate in the early months. Fe- and S oxidizing bacterial populations generally decreased over time. This suggests that hydro-dam sediments can remain stable after being decommissioned. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
1:25 PM-5:05 PM, Sunday, March 28, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |