(SGER) Collaborative Research: Transport and Fate of Mercury Within the Carson River Valley During the January 1997 Flood

(SGER) 合作研究：1997 年 1 月洪水期间卡森河谷内汞的迁移和归宿

• 批准号: 9714150
• 负责人: Jerry Miller
• 金额: $ 0.38万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 1998-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9714150&HistoricalAwards=false
• 关键词: SGER; Collaborative; Research; Transport; Fate

9714150 Miller Mining of the Comstock Lode (1860-1890) resulted in the release of an estimated 7,500 tons of mercury to the Carson River system including Lahontan Reservoir. Much of the polluted sediment is associated with filled paleochannels which are thought to have been produced by the filling of abandoned meanders previously cutoff from the main channel. Given that a majority of the present day mercury load in the Carson River is derived from bank erosion, it follows that during floods, much of the eroded sediment is returned to storage by the deposition of sediment within the channels of the abandoned meanders. Thus, there may be a cycling of contaminated debris between the channel and the valley fill during flood events which inundated the valley floor. In early January, 1997 flood flows, with a magnitude which has only been exceeded once in the past 57 years of record, inundated large regions of the Carson River valley. Field observations made during and following the event revealed that numerous reaches along the channel suffered extensive erosion, while thick sedimentary sequences were deposited over other regions of the valley floor. Based on these field observations, we believe that this low frequency, high magnitude event had a significant affect on the transport and storage of mercury contaminated particles along the Carson River valley. The primary objectives of this investigation are to (1) document the patterns of erosion and deposition that occurred along the Carson River valley from Carson City to Lahontan Reservoir during the January, 1997 flood, (2)determine the spatial variations in mercury concentration that occur within the newly formed flood deposits, and (3) assess the primary controls on both the deposition of contaminated sediments and the distribution of mercury within those deposits. By combining the conclusions reached in this investigation with previous studies of the Carson River, we will be able to assess the transport and fate of mercury by phys ical processes over time periods ranging from individual flood events to decades. In addition, a comparison of the geographic trends measured prior to and following the storm will lead to significant insights into the importance of rare, high magnitude floods on the dispersal of heavy metals in alluvial deposits.

9714150米勒 康斯托克矿脉的开采（1860-1890年）导致约7，500吨汞释放到包括拉洪坦水库在内的卡森河系统。 大部分受污染的沉积物与被填充的古河道有关，这些古河道被认为是由以前从主河道切断的废弃河曲的填充产生的。 鉴于目前卡森河中的大部分汞负荷来自河岸侵蚀，因此在洪水期间，大部分侵蚀沉积物通过废弃河曲河道内的沉积物沉积而返回储存。 因此，在淹没谷底的洪水事件期间，受污染的碎片可能在渠道和山谷填充物之间循环。 1997年1月初，洪水淹没了卡森河谷的大片地区，其规模在过去57年的记录中只超过一次。 在事件发生期间和之后进行的实地观察表明，沿着许多河段遭受了广泛的侵蚀，而在谷底的其他地区则沉积了厚厚的沉积序列。 基于这些现场观测，我们认为，这种低频率，高强度的事件有一个显着的影响，沿着卡森河流域的汞污染颗粒的传输和存储。 本次调查的主要目的是（1）记录1997年1月洪水期间从卡森市到拉洪坦水库的卡森河沿着的侵蚀和沉积模式，（2）确定新形成的洪水沉积物中汞浓度的空间变化，以及（3）评估对受污染沉积物的沉积以及汞在这些沉积物中的分布的主要控制措施。 通过将本次调查得出的结论与之前对卡森河的研究相结合，我们将能够评估从单个洪水事件到数十年的时间段内物理过程对汞的迁移和归宿。 此外，在风暴之前和之后测量的地理趋势的比较将导致显着的见解罕见的，高强度的洪水对冲积矿床中的重金属的分散的重要性。