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

RAPID：提高对活性有机碳源和砷在减少含水层中的迁移率的认识

• 批准号: 1449247
• 负责人: Natalie Mladenov
• 金额: $ 4.44万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1449247&HistoricalAwards=false
• 关键词: RAPID; Toward; anIimproved; Understanding; Reactive

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.

CBET-1449247 Mladenov RAPID：为了更好地了解活性有机碳源和砷的流动性，减少含水层砷是一个世界性的问题，在地下水作为饮用水的来源。2007年的一项研究表明，包括美国在内的70多个国家的1.37亿多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性质，以便为处理水的工程决策提供信息，使其可以安全饮用。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。对于DOM的来源，即DOM是废水排放的结果还是自然来源，存在一些争议。两者都有可能;但似乎在大多数情况下，地下沃茨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性质。识别驱动微生物还原的活性有机碳（DOM）来源的挑战继续限制我们预测砷在还原性含水层中分布的能力。拟议的研究是一个协调一致的努力，相关的分析方法溶解有机物（DOM）的表征和荧光光谱采集的DOM从不妥协的沉积物孔隙水的反应。这将提供新的信息的潜力和限制的荧光光谱表征DOM在还原环境中，往往有高的金属含量。此外，通过在有和没有大规模抽水的地点进行协调的钻探工作，DOM化学表征和放射性碳测年的大体积采样将测试假设，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，以驱动砷的微生物还原溶解。将收集和分析样本，以提供有关可推广到其他含水层的各种情况下的DOM来源和年龄的关键信息。利用独特的冻鞋取样技术和移动的实验室，这项工作将允许优化适合于大体积取样、不折不扣的孔隙水取样和快速DOM表征的技术。这项研究利用了2014年夏天来自16个不同国家的科学家和学生收集的多个数据集。钻探工作利用新型的冻鞋取样技术，从含砷的Mahomet含水层（伊利诺伊州）收集未受损的沉积物和邻近的孔隙水，以便在现场的移动的实验室立即进行分析。拟议的RAPID项目将支持在Mahomet含水层现场采集样本，并准备用于放射性碳测年和蛋白质、碳水化合物和富里酸测定的样本。下一次类似的大规模抽样将不会在三年内进行。