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

地下水中砷的浓度部分由沉积物浓度决定，但也由沉积物矿物学和影响它们的变化决定。该项目的第一个目标是在项目5（葡萄地）、项目6（孟加拉国）和项目核心中概述的综合采样工作中检查水砷（和其他分析物）的空间分布，将地下水砷水平与有形水和沉积物特性(例如，矿物学，使用最先进的光谱方法测量，包括铁、砷、和S - x射线光谱)以及转化它们的生物群落（有16个rDNA群落文库和功能基因分析）。作为这项综合工作的一部分，该项目将描述调节溶解As浓度的Fe、As和S相，确定含水层中影响这些相的活性氧化还原过程和促进这些过程的细菌，并确定哪些活性碳库驱动微生物呼吸。该项目的第二个总体目标是研究沉积物矿物学和含水层地球化学变化对砷水平的影响。在Araihazar的模拟池塘村和Vineland超级基金站点中，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的实验室实验中监测这些参数和其他参数如何随时间变化。这些批和柱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、铁、硫和砷矿物学以及砷地球化学的影响。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的目标），并将使我们能够第一次检查相关和基本环境过程的速率。结果数据将用于开发和校准反应输运模型，以更准确地捕获影响As分配的过程（项目5,6，水文地质核心）。这些数据还将用于在葡萄园超级基金现场设计改进的修复解决方案。

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.