Project 4: Arsenic, Iron, Sulfur and Organic Carbon Speciation and Their Impact

地下水中砷的浓度部分取决于它们的沉积物浓度，但也取决于沉积物矿物学和影响它们的转化。该项目的第一个目标是在项目5(越南)、6(孟加拉国)概述的全面采样工作中检查水中砷(和其他分析物)的空间分布，以及将地下水砷水平与有形的水和沉积物性质(例如矿物学，使用包括铁、砷和S X射线光谱学在内的最先进的光谱方法测量的矿物学)以及转化它们的生物群落(具有16个rDNA群落文库和功能基因分析)相联系的岩芯。作为这项综合工作的一部分，该项目将确定调节溶解砷浓度的铁、砷和S相的特征，确定含水层中影响这些相的活跃氧化还原过程以及促进这些过程的细菌，并确定哪些活性碳池驱动微生物呼吸。该项目的第二个首要目标是审查沉积物矿物学和含水层地球化学中的变化对砷水平的影响。在Araihazar的模拟池塘村庄和Vinland Superfund现场，我们将研究沉积物矿物学、氧化还原状态、微生物种群和砷水平之间的关系，但我们也将能够在受控实验室实验中监控这些参数和其他参数如何随时间变化。这些批次和柱状研究将使用天然沉积物，并将探索地球化学条件的扰动对沉积物生物地球化学过程的影响，包括Fe、S和As矿物学，以及As地球化学。这些操作将直接探讨人类活动对砷污染的影响问题(适用于项目。6个目标)，并将使我们能够第一次审查相关和基本环境过程的比率。然后，生成的数据将用于开发和校准反应性传输模型，以更准确地捕获影响AS分区(项目)的过程。5、6、水文地质岩心)。这些数据还将用于设计Vinland Superfund现场改进的补救解决方案。

Arsenic groundwater concentrations are determined in part by their sediment concentration but also by sediment mineralogy and the transformations that affect them. The first goal of this project is to examine the spatial distribution of aqueous As (and other analytes) within the comprehensive sampling efforts outlined in Projects 5 (Vineland), 6 (Bangladesh) and Cores to link groundwater As levels to tangible aqueous and sediment properties (e.g., mineralogy, measured using state-of-the-art spectroscopic methods including Fe, As, and S X-ray spectroscopy) and the biological communities that transform them (with 16 rDNA community libraries and functional gene analysis). As part of this comprehensive effort, this project will characterize the Fe, As and S phases that regulate dissolved As concentrations, identify active redox processes in the aquifer that affect these phases and the bacteria that facilitate these processes, and determine which active carbon pools drive microbial respiration. The second overarching goal of this project is to examine the role of transformations in sediment mineralogy and aquifer geochemistry on arsenic levels. Within the simulated pond-village in Araihazar, and the Vineland Superfund Site, we will study the relationship between sediment mineralogy, redox status, microbial populations and arsenic levels, but we will also be able to monitor how those and other parameters change over time in controlled laboratory experiments. These batch and column studies will use natural sediments and will probe the effect of perturbations of geochemical conditions on sediment biogeochemical processes, Fe, S and As mineralogies, and As geochemistry. These manipulations will directly probe the question of the effect of human activity on As contamination (applicable to Proj. 6 goals), and will allow us to examine the rates of relevant and fundamental environmental processes for the first time. The resulting data will then be used to develop and calibrate reactive transport models that more accurately capture the processes that affect As partitioning (Proj. 5, 6, Hydrogeology Core). These data also will be used to engineer improved remediation solutions at the Vineland Superfund site.