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

FEINEAR-0207169在拟议的研究计划中，我们将使用天然和实验室生成的样品的X射线吸收光谱(XAS)来确定金属-细菌吸附在影响细菌-水-岩石系统中金属分布的重要性。这项研究的总体目标是测试表面络合模型是否能够解释在一系列条件和复杂性下观察到的金属分布。量化细菌对水-岩系统中吸附反应的影响不仅在污染物迁移模拟中有直接的应用，而且在生物修复工程和了解细菌病原体的迁移性方面也有直接的应用。拟议的研究将最终导致对受污染的地下水系统中水中金属的流动性的更准确的预测。拟议的研究将提供三件事：1)通过XAS和整体吸附测量，了解细菌表面对水中金属阳离子的吸附是否在含细菌的水-岩石系统中的金属形态形成中起重要作用；2)严格测试表面络合模型是否能够解释这些系统中的金属分布；以及3)测试自然细菌种群是否表现出相同的金属吸附特性，如Yee和Fein(2001a，b)的数据所表明的那样。这项研究的实验结果不仅将加深我们对金属-细菌相互作用的理解，而且还将显著提高我们准确模拟细菌吸附对现实地质系统中重金属命运和迁移的影响的能力。

FeinEAR-0207169In 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.