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，工业场地和其他污染源的地下水污染。我的研究包括地下水流系统的物理和溶质运输特性的测定，溶解成分的浓度和形态的测量，控制溶解成分浓度的初级和次级阶段的识别，以及金属和养分循环中所涉及的微生物群落的表征。我们研究的系统是复杂的，这使得开发良好约束的预测具有挑战性。我们目前正在探索使用非传统的同位素测量，基于同步加速器的光谱技术，下一代微生物种群测序和反应性运输建模，以提高我们对污染场地和修复系统的水文地质学和地球化学的理解。集成这些技术将提供额外的限制反应性运输模拟。我们将进行一系列高度约束（恒定T，P，PO 2，PCO 2）的实验室实验，以确定与吸附，还原-氧化和沉淀的碳酸盐，氢氧化物，磷酸盐，硫化物相含铜，铁，镍，硒，锌，氢氧化物相含铬的同位素分馏的程度。将使用同步加速器X射线吸收光谱（XAS）分析来自这些实验的反应产物以确定氧化态和结构。此外，我们将在同步加速器设施进行流通细胞实验，以监测稳定水流下氧化态的变化和同位素比的相应变化。这种方法将提供测量的反应机制，反应速率，反应进程，和同位素分馏在一个前所未有的详细程度。将使用分子方法表征流通池中存在的微生物群落。将非传统的同位素比率测量与基于同步加速器的反应过程和反应产物的表征以及微生物群落结构的表征相结合，将为数字建模提供坚实的基础，并改进对环境污染的程度和持续时间以及补救系统的有效性和寿命的评估。

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.