Collaborative Research: Establishing Process Links Between Streamflow, Sediment Transport/Storage, and Biogeochemical Processing of Mercury

合作研究：建立水流、沉积物运输/储存和汞生物地球化学处理之间的过程联系

• 批准号: 1225630
• 负责人: Joel Blum
• 金额: $ 15.5万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1225630&HistoricalAwards=false
• 关键词: Collaborative; Research; Establishing; Process; Links

The proposed work is an investigation of mercury (Hg) in river systems that have experienced large anthropogenic inputs of this toxic substance (e.g., by upstream mining). This interdisciplinary project will identify critical locations in river systems where the risk of Hg input to food webs increases and elucidate the processes by which this occurs. The study will focus on the longitudinal (downstream) transport and biogeochemical processing of sediment-adsorbed Hg derived from hydraulic gold mining in the Sierra Nevada and mercury mining in the Coast Ranges within and through the Yuba-Feather-Sacramento River system of Northern California, USA. It will document the primary sources (Coast Range v. Sierra Nevada) of Hg contamination to lowland ecosystems in the Sacramento Valley and Bay-Delta and the relative contribution and risks of each. We will: 1) mathematically model flood inundation in river corridors to identify areas of high potential of oxidation/reduction; 2) identify preferential zones of sedimentation through numerical modeling of event-based washload transport; 3) identify distinct contamination sources to lowlands by conducting Hg stable isotopic analysis of sediment; and 4) investigate Hg speciation in conjunction with changes in Hg species isotopic signatures, associated with redox conditions and sediment source. In river basins beset by Hg contamination from atmospheric deposition or anthropogenic inputs from mining, there is great uncertainty about the interplay among sediment transport, deposition, and remobilization and the evolution of Hg reactivity in response to inundation regimes and ambient chemistry. These factors have important implications for bioavailability of sediment-adsorbed Hg to food webs, as it travels to sensitive downstream ecosystems where methylation potential is high. This research will address this problem and provide new understanding into the physical and biogeochemical processes that threaten sensitive lowland ecosystems. The importance of sediment deposits originating from legacy mines, especially in the Bay-Delta watershed, has recently increased due to realizations that they may contain high levels of Hg that may be available to food webs. These factors are being investigated by various government agencies and nonprofit groups responsible for river basin management. The research team has developed close contacts and relations with personnel from interested parties in the US with whom findings will be shared.

拟议的工作是对河流系统中汞（HG）的研究，这些汞（HG）经历了这种有毒物质的大量人为输入（例如，上游采矿）。这个跨学科项目将确定河流系统中的关键位置，在这些项目中，对食品网的输入的风险增加并阐明发生这种情况的过程。该研究将集中于纵向（下游）的运输和生物地球化学处理，这些沉积物吸附的汞源于内华达山脉的液压金矿开采和沿海地区的汞矿开采以及美国北加利福尼亚州北加利福尼亚州的Yuba-Feather-Feather-Sacramento River System。它将记录HG污染对萨克拉曼多山谷和海湾 - 戴尔塔低地生态系统的主要来源（Coast Rangev。SierraNevada），以及每个人的相对贡献和风险。我们将：1）数学上对河流走廊的洪水进行建模，以识别氧化/还原潜力高的区域； 2）通过基于事件的洗涤传输的数值建模来确定沉积的优先区域； 3）通过对沉积物进行HG稳定的同位素分析来确定对低地的明显污染源； 4）研究与HG物种同位素特征的变化一起研究HG形成，与氧化还原条件和沉积物来源有关。在河流盆地被大气沉积或采矿的人为输入中的HG污染困扰中，关于沉积物传输，沉积和重新验证之间的相互作用以及HG反应性的反应性在遭受育入方案和环境化学的响应时，HG反应性的演变存在很大的不确定性。这些因素对沉积物吸附的汞的生物利用度具有重要意义，因为它传播到甲基化潜力较高的敏感下游生态系统。这项研究将解决这个问题，并对威胁敏感低地生态系统的物理和生物地球化学过程提供新的理解。源自传统矿山的沉积物矿床的重要性，尤其是在海湾流域中，由于认识到它们可能包含可能可用于食品网的高水平的HG，因此最近有所增加。这些因素正在由负责河流管理的各个政府机构和非营利组织进行调查。研究团队已经与美国有兴趣的人的人员建立了密切的联系和关系，并将与他们分享发现。