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: 1226741
• 负责人: Michael Singer
• 金额: $ 9.65万
• 依托单位: University of California-Santa Barbara
• 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 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1226741&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.

拟议的工作是调查河流系统中的汞（Hg），这些河流系统经历了大量人为输入的这种有毒物质（例如，上游矿业）。这一跨学科项目将确定河流系统中汞进入食物网风险增加的关键位置，并阐明发生这种情况的过程。该研究将重点关注美国北方加州的Yuba-Feather-萨克拉门托河流系统内和通过该系统的沉积物吸附汞的纵向（下游）迁移和生物地球化学处理，这些汞来自Sierra内华达州的水力金矿开采和Coast Ranges的汞开采。它将记录萨克拉门托河谷和海湾三角洲地区低地生态系统汞污染的主要来源（海岸山脉诉内华达州山脉案），以及各自的相对影响和风险。我们将：1）对河流廊道中的洪水淹没进行数学建模，以确定高氧化/还原潜力区域; 2）通过基于事件的冲刷量输运的数值模拟，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）结合汞形态同位素特征的变化，探讨汞的形态分布与氧化还原条件和沉积物来源的关系。在河流流域汞污染的困扰，从大气沉积或人为输入采矿，有很大的不确定性之间的相互作用，沉积物的运输，沉积和再动员和汞反应性的演变，以应对洪水制度和环境化学。这些因素对沉积物吸附的汞进入食物网的生物利用度具有重要影响，因为汞会进入甲基化潜力高的敏感下游生态系统。这项研究将解决这一问题，并提供新的理解到物理和地球化学过程，威胁敏感的低地生态系统。由于人们认识到，遗留矿山（尤其是海湾三角洲流域）产生的沉积物可能含有大量可供食物网使用的汞，因此其重要性最近有所增加。负责流域管理的各种政府机构和非营利组织正在调查这些因素。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，并将与他们分享研究结果。