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的汞（Hg）进行调查，这些系统经历了这种有毒物质的大量人为输入（例如，通过上游采矿）。这个跨学科项目将确定河流系统中汞输入食物网风险增加的关键位置，并阐明这种情况发生的过程。该研究将重点关注内华达山脉水力金矿开采中沉积物吸附汞的纵向（下游）迁移和生物地球化学处理，以及北加州尤巴-费瑟-萨克拉门托河系统内和通过的海岸山脉汞矿开采，美国。它将记录萨克拉门托山谷和海湾三角洲低地生态系统汞污染的主要来源（海岸山脉与内华达山脉）以及每个来源的相对贡献和风险。我们将： 1）对河流走廊的洪水淹没进行数学建模，以确定氧化/还原潜力较高的区域； 2) 通过基于事件的冲刷物输送的数值模型确定沉积的优先区域； 3) 通过对沉积物进行汞稳定同位素分析，确定低地的不同污染源； 4) 研究汞形态以及与氧化还原条件和沉积物来源相关的汞形态同位素特征的变化。在受到大气沉积汞污染或采矿人为输入汞污染的河流流域中，沉积物迁移、沉积和再流动之间的相互作用以及汞反应性对淹没状况和环境化学反应的演变存在很大的不确定性。这些因素对沉积物吸附的汞在食物网中的生物利用度具有重要影响，因为它会进入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，并为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认识。来自遗留矿山的沉积物沉积物的重要性，特别是在海湾三角洲流域，最近变得越来越重要，因为人们认识到这些沉积物可能含有高含量的汞，而这些汞可被食物网吸收。负责流域管理的各个政府机构和非营利组织正在对这些因素进行调查。研究小组与美国有关方面的人员建立了密切的联系和关系，并与他们分享研究结果。