Contaminant Loading of Watersheds From Snowmelt: An Integrated Study Using Stable Isotopes and Rare Earth Elements

融雪造成的流域污染物负荷：利用稳定同位素和稀土元素进行的综合研究

• 批准号: 9903281
• 负责人: Xiahong Feng
• 金额: $ 19.14万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-15 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9903281&HistoricalAwards=false
• 关键词: Contaminant; Loading; Watersheds; Snowmelt; Integrated

9903281FengSnowpacks collect and store acid deposition and chemical pollutants from the atmosphere throughout the winter. In the spring, these pollutants are released into watersheds in a very short time; the first 30% of melt contains up to 80% of the solutes. Such an intensive release of acid and other chemicals significantly affects water quality and aquatic environments.This project focuses on developing a quantitative understanding of the chemical and physical controls on the isotopic and chemical compositions of snowmelt at two well-equipped snow laboratories: Central Sierra Snow Laboratory in California and Sleepers River Research Watershed in Vermont. The integration of isotopic and chemical analyses of these two sites will provide a more complete understanding of the processes controlling meltwater generation than is possible when either tracer is used alone. Rare earth elements (RFTs) will be used as chemical tracers within the snowpack. These tracers will not only identify and trace water from individual snow events, but also provide data that will help elucidate the profiles and snowmelt. This will enable us to evaluate isotopic redistribution within the snowpack during snow metamorphism and the modification of this composition by liquid-ice exchange as water percolates down the snow column. Cold room experiments, conducted at the U.S. Army's Cold Regions Research and Engineering Laboratory, will complement the field studies by allowing us to monitor oxygen isotope values of snowmelt as a function of different melt rates and grain size. Both the field and experimental data will be used to develop and parameterize physically based models of isotopic and chemical transport through the snowpack. Ultimately, the understanding of contaminant transport gained from this work will be extended to entire watersheds.

9903281 Fengsnowpacks在整个冬季从大气中收集并存储酸沉积和化学污染物。 在春季，这些污染物在很短的时间内被释放到流域。前30％的熔体包含多达80％的溶质。 这种密集的酸和其他化学物质的释放显着影响水质和水生环境。该项目着重于对两个设备齐全的雪地实验室的同位素和化学物质组成的化学和物理控制进行定量理解：加利福尼亚州的中部塞拉利昂雪地实验室和佛蒙特州的Slopeer河水研究。 这两个位点的同位素和化学分析的整合将提供对控制融化产生的过程的更完整的理解，而不是单独使用示踪剂。 稀土元素（RFT）将用作积雪中的化学示踪剂。 这些示踪剂不仅将识别和追踪各个雪事件中的水，而且还提供了有助于阐明剖面和融雪的数据。 这将使我们能够在雪变质过程中评估积雪内的同位素重新分布，并通过液体冰交换来修饰这种成分，因为水渗入了雪柱。 在美国陆军冷区研究和工程实验室进行的冷室实验将通过允许我们监视融雪的氧同位素值作为不同熔体速率和谷物尺寸的函数来补充现场研究。 场和实验数据都将用于通过积雪开发和参数化基于物理和化学转运的物理模型。 最终，从这项工作中获得的污染物运输的理解将扩展到整个流域。