Integration of Innovative Techniques to Improve Prediction and Remediation of Groundwater Contamination

我的研究计划的长期目标是开发改进的技术，用于预测、修复和预防来自矿山、工业场所和其他污染源的地下水污染。我的研究包括确定地下水流动系统的物理和溶质运输特性，测量溶解成分的浓度和形态，鉴定控制溶解成分浓度的初级和次级相，以及表征参与金属和营养循环的微生物群落。我们研究的系统是复杂的，因此很难做出约束良好的预测。我们目前正在探索非传统同位素测量、基于同步加速器的光谱技术、新一代微生物种群测序和反应输运模型的使用，以增强我们对污染地点和修复系统的水文地质和生物地球化学的理解。集成这些技术将为反应传输模拟提供额外的约束。我们将进行一系列高约束（恒定T， P, PO2, PCO2）实验室实验，以确定与碳酸盐，氢氧化物，磷酸盐和含Cu， Fe, Ni， Se和Zn的硫化物相以及含Cr的氢氧化物相的吸附，还原氧化和沉淀相关的同位素分馏程度。这些实验的反应产物将使用同步加速器x射线吸收光谱（XAS）分析以确定氧化状态和结构。此外，我们将在同步加速器设施上进行流过细胞实验，以监测稳定水流下氧化态的变化和相应的同位素比值的变化。这种方法将以前所未有的详细程度提供反应机理、反应速率、反应过程和同位素分馏的测量。存在于流式细胞中的微生物群落将使用分子方法进行表征。将非传统同位素比测量与基于同步加速器的反应过程和反应产物表征以及微生物群落结构表征相结合，将为数值模拟和改进对环境污染程度和持续时间以及补救系统的有效性和寿命的评估提供坚实的基础。

The long-term goal of my research program is to develop improved techniques for the prediction, remediation, and prevention of groundwater contamination derived from mine sites, industrial sites, and other sources of contamination. My research includes determination of the physical and solute-transport characteristics of groundwater flow systems, measurements of the concentration and speciation of dissolved constituents, identification of primary and secondary phases controlling the concentrations of dissolved constituents, and characterization of the microbiological communities involved in metal and nutrient cycling. The systems we study are complex, making it challenging to develop well-constrained predictions. We are currently exploring the use of non-traditional isotope measurements, synchrotron-based spectroscopic techniques, next-generation sequencing of microbial populations, and reactive transport modelling to enhance our understanding of the hydrogeology and biogeochemistry of contaminated sites and remediation systems. Integrating these techniques will provide additional constraints on reactive transport simulations. We will conduct a series of highly-constrained (constant T, P, PO2, PCO2) laboratory experiments to determine the extent of isotope fractionation associated with adsorption, reduction-oxidation, and precipitation of carbonate, hydroxide, phosphate, and sulfide phases containing Cu, Fe, Ni, Se, and Zn, and hydroxide phases containing Cr. The reaction products from these experiments will be analyzed using synchrotron X-ray absorption spectroscopy (XAS) to determine oxidation state and structure. In addition, we will conduct flow-through cell experiments at synchrotron facilities to monitor changes in oxidation state and corresponding changes in isotope ratios under steady water-flow. This approach will provide measurements of the reaction mechanism, reaction rate, reaction progress, and isotope fractionation at an unprecedented level of detail. The microbial community present in the flow-through cell will be characterized using molecular approaches. Combining non-traditional isotope-ratio measurements, with synchrotron-based characterization of reaction processes and reaction products, and characterization of microbial community structure, will provide a strong foundation for numerical modelling, and improved assessments of the extent and duration of environmental contamination, and the effectiveness and longevity of remediation systems.