RAPID: Toward anIimproved Understanding of Reactive Organic Carbon Sources and Arsenic Mobility in Reducing Aquifers

CBET-1449247 Mladenov快速：为了更好地了解活性有机碳源和砷在减少含水层方面的流动性，砷在用作饮用水来源的地下水中是一个世界性的问题。2007年的一项研究表明，包括美国在内的70多个国家的1.37亿人受到这种毒药的影响。一个挑战是更好地了解地下水中砷的化学成分，以便为处理这些水的工程决策提供信息，使其能够安全饮用。其中一个重要的考虑因素是溶解有机物的存在，通常被称为DOM。关于这一DOM的来源存在一些争议，即它是废水排放的结果还是来自自然来源。这两种情况都是可能的；然而，似乎在大多数情况下，地下水中存在的是天然存在的有机物。反过来，这种DOM可以与微生物自然反应，这反过来又会影响砷的化学成分。识别推动微生物减少的活性有机碳(DOM)来源的挑战继续限制了我们预测减少含水层中砷的分布的能力。这项拟议的研究是一项共同努力，旨在将溶解有机物(DOM)表征的分析方法和反应性与从未受影响的沉积物孔隙水中收集的DOM的荧光光谱获取相关联。这将提供有关荧光光谱在通常具有高金属含量的还原环境中表征DOM的潜力和限度的新信息。此外，通过在有和没有大规模抽水的地点进行的协调钻探工作，DOM的化学特征和用于放射性碳测年的大量采样将检验这样的假设，即在没有大规模灌溉抽水的情况下，沉积物可能提供不稳定的DOM来驱动微生物还原溶解砷。将收集和分析样本，以提供可推广到其他含水层的情况下关于DOM来源和年龄的关键信息。利用独特的冰冻鞋采样技术和移动实验室的可用性，这项工作将使适用于大容量采样、不妥协的孔隙水采样和快速DOM表征的技术得到优化。这项拟议的研究利用了来自16个不同国家的科学家和学生在2014年夏天收集的多个数据集。钻探工作利用新颖的冰鞋采样技术，从含砷的穆罕默德含水层(伊利诺伊州)收集未受影响的沉积物和邻近的孔隙水，并在现场的流动实验室立即进行分析。拟议的快速项目将支持在穆罕默德含水层现场采集样品，并为放射性碳测年和蛋白质、碳水化合物和黄腐酸的测定准备样品。下一次类似的大规模抽样将不会在三年内进行。

CBET-1449247 Mladenov RAPID: Toward an improved understanding of reactive organic carbon sources and arsenic mobility in reducing aquifers Arsenic is a world-wide issue in groundwater when used as a source of drinking water. A study in 2007 suggests that over 137 million people in more than 70 countries, including the United States, are affected by this poison. A challenge is to better understand the chemistry of arsenic in groundwater in order to inform engineering decisions in treating that water to make is safe for drinking. One of the important considerations is the presence of dissolved organic matter, often referred to as DOM. There is some controversy over the source of this DOM, as to whether it is the result of the discharge of wastewater or is from natural sources. Both are possible; however it appears that in most cases it is naturally occurring organic matter that is present in the ground waters. In turn, this DOM can react naturally with microorganisms, which in turn can affect the chemistry of the arsenic. The challenge of identifying the sources of reactive organic carbon (DOM) driving microbial reduction continues to limit our ability to predict the distribution of arsenic in reducing aquifers. The proposed research is a concerted effort to correlate analytical methods for dissolved organic matter (DOM) characterization and reactivity to fluorescence spectral acquisition of DOM collected from uncompromised sediment pore-water. This will provide new information about the potential and limits of fluorescence spectroscopy for characterizing DOM in reducing environments that often have high metal content. In addition, via this coordinated drilling effort at sites with and without large-scale pumping, DOM chemical characterization and large volume sampling for radiocarbon dating will test the hypothesis that, in the absence of massive irrigation pumping, sediments may provide labile DOM to drive microbial reductive dissolution of arsenic. Samples will be collected and analyzed to provide key information regarding DOM source and age under scenarios that are generalizable to other aquifers. With the unique freeze-shoe sampling technology and availability of a mobile laboratory, this effort will allow for the optimization of techniques appropriate for large volume sampling, uncompromised pore-water sampling, and rapid DOM characterization. The proposed research takes advantage of multiple datasets being collected by scientists and students from 16 different countries in the summer of 2014. The drilling effort utilizes novel freeze-shoe sampling technology to collect uncompromised sediments and adjacent pore-waters from the arsenic-containing Mahomet Aquifer (Illinois) for immediate analysis at a mobile laboratory at the site. The proposed RAPID project will support sample collection at the Mahomet Aquifer field site and preparation of samples for radiocarbon dating and determinations of proteins, carbohydrates, and fulvic acids. The next large sampling similar to this will not be for three years.