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

砷地下水浓度部分取决于其沉积物浓度，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（葡萄园）、项目6（孟加拉国）和岩心中概述的全面取样工作中检查含水As（和其他分析物）的空间分布，以将地下水As水平与有形的含水和沉积物特性（例如，矿物学，使用最先进的光谱方法，包括Fe，As和S X射线光谱测量）和转化它们的生物群落（16个rDNA群落文库和功能基因分析）。作为这一全面努力的一部分，该项目将表征调节溶解As浓度的Fe，As和S相，确定影响这些相的含水层中的活性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。该项目的第二个总体目标是研究沉积物矿物学和含水层地球化学的变化对砷含量的影响。在Araihazar的模拟池塘村庄和Vineland Superfund网站内，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测这些参数和其他参数如何随时间变化。这些批次和柱研究将使用天然沉积物，并将探测地球化学条件扰动对沉积物地球化学过程、Fe、S和As矿物学以及As地球化学的影响。这些操作将直接探讨人类活动对As污染的影响问题（适用于项目1999年12月28日）。6个目标），并将使我们能够首次检查相关和基本环境过程的速率。由此产生的数据将被用来开发和校准反应性运输模型，更准确地捕捉影响作为分区的过程（项目。5、6、水文地质岩心）。这些数据还将用于设计Vineland Superfund站点的改进修复解决方案。

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.