HR: 10:50h
AN: B22A-02    [Abstracts]
TI: Modeling Biogeochemical Cycling of Heavy Metals in Lake Coeur d'Alene Sediments
AU: * Sengor, S S
EM: sssengor@ucdavis.edu
AF: University of California-Davis, One Shields Avenue Civil and Environmental Engineering Department, Davis, CA 95616 United States
AU: Spycher, N
EM: nspycher@lbl.gov
AF: Lawrence Berkeley Natinal Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 United States
AU: Belding, E
EM: embelding@ucdavis.edu
AF: University of California-Davis, One Shields Avenue Civil and Environmental Engineering Department, Davis, CA 95616 United States
AU: Curthoys, K
EM: kscurthoys@ucdavis.edu
AF: University of California-Davis, One Shields Avenue Civil and Environmental Engineering Department, Davis, CA 95616 United States
AU: Ginn, T R
EM: trginn@ucdavis.edu
AF: Lawrence Berkeley Natinal Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 United States
AB: Mining of precious metals since the late 1800's have left Lake Coeur d'Alene (LCdA) sediments heavily enriched with toxic metals, including Cd, Cu, Pb, and Zn. Indigenous microbes however are capable of catalyzing reactions that detoxify the benthic and aqueous lake environments, and thus constitute an important driving component in the biogeochemical cycles of these metals. Here we report on the development of a quantitative model of transport, fate, exposure and effects of toxic compounds on benthic microbial communities at LCdA. First, chemical data from the LCdA area have been compiled from multiple sources to investigate trends in chemical occurrence, as well as to define model boundary conditions. The model is structured as 1-D diffusive reactive transport model to simulate spatial and temporal distribution of metals through the benthic sediments. Inorganic reaction processes included in the model are aqueous speciation, surface complexation, mineral precipitation/dissolution and abiotic redox reactions. Simulations with and without surface complexation are carried out to evaluate the effect of sorption and the conservative behaviour of metals within the benthic sediments under abiotic and purely diffusive transport. The 1-D inorganic diffusive transport model is then coupled to a biotic reaction network including consortium biodegradation kinetics with multiple electron acceptors, product toxicity, and energy partitioning. Multiyear simulations are performed, with water column chemistry established as a boundary condition from extant data, to explore the role of biogeochemical dynamics on benthic fluxes of metals in the long term.
DE: 0408 Benthic processes (4804)
DE: 0412 Biogeochemical kinetics and reaction modeling (0414, 0793, 1615, 4805, 4912)
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0466 Modeling
SC: Biogeosciences [B]
MN: Fall Meeting 2005