Measuring and Modeling Metal Adsorption in Bacteria-Water-Rock Systems

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

Fein EAR-0207169 In the proposed research program, we will use x-ray absorption spectroscopy (XAS) of natural and laboratory-generated samples to determine the importance of metal-bacteria adsorption in affecting the distribution of metal in bacteria-water-rock systems. The overall objective of the research is to test whether surface complexation modeling can account for the observed metal distributions under a range of conditions and complexities. Quantifying the effects of bacteria on adsorption reactions in water-rock systems has direct applications not only to contaminant transport modeling, but also to bioremediation engineering and to the understanding of bacterial pathogen mobility. The proposed research will ultimately lead to more accurate predictions of the mobility of aqueous metals in contaminated groundwater systems. The proposed research will deliver three things: 1) an understanding, provided by both XAS and bulk adsorption measurements, of whether bacterial surface adsorption of aqueous metal cations plays an important role in metal speciation in bacteria-bearing water-rock systems; 2) a rigorous testing of whether surface complexation modeling can account for the metal distribution in those systems; and 3) a test of whether natural populations of bacteria exhibit identical metal adsorption properties, as was suggested by the data of Yee and Fein (2001a,b). The experimental results from this research not only will further our understanding of metal-bacteria interactions, but they will also significantly improve our ability to accurately model the effects of bacterial adsorption on the fate and mobility of heavy metals in realistic geologic systems.