Doctoral Dissertation Research: Using Ice-Core Data to Reconstruct Atmospheric Mercury Deposition Over the Past 17,000 Years.

本博士论文项目的目的是揭示自然和人为控制汞沉积到北美西北部。人类排放的汞，主要来自采矿、冶炼和燃煤，目前正在上升，主要来自亚洲。从亚洲到北美西北部的汞运输可能会造成新的生态和健康危害，导致河流和鱼类中已经很高的汞含量。然而，为了评估不断上升的汞污染对生态系统的影响，还必须确定火山活动、风化和森林火灾产生的随时间变化的天然汞水平。勘探者罗素冰芯（PRCol）是在2001年和2002年从加拿大育空地区洛根山山顶采集的，它是这项研究的理想选择，因为它位于亚洲污染源的下风位置，而且它的年代记录跨越了过去1.7万年。本研究将采用清洁取样技术和最先进的分析方法，在1至100年的时间尺度上测量PRCol冰芯中的汞浓度。该冰芯中的汞浓度将与火山爆发、森林火灾、灰尘和气候的记录进行比较，以确定对汞水平自然变化的控制。人类汞污染对该地区的影响将通过比较20世纪沉积的汞浓度与大规模人类汞污染之前17000年沉积的汞浓度来确定。将通过比较20世纪的气候参数和汞浓度来研究厄尔尼诺等气候模式对汞运输和沉积的影响。确定最近汞污染的规模和趋势是解决全球环境中汞污染问题的一个基本步骤。这项研究的结果将通过学术出版物和会议传播。将训练一名本科生研究助理协助本研究并完成相关子课题。这些pi将在当地中学宣传他们的研究，并将其与地球科学领域的职业讨论结合起来。国际合作将通过ppi和加拿大研究人员之间的密切合作来建立，加拿大研究人员收集并已经对来自冰芯的数据进行了一些分析。作为博士论文研究进步奖，该项目将为有前途的研究生建立独立的研究生涯提供支持。

The objective of this doctoral dissertation project is to reveal the natural and human controls on mercury deposition to northwestern North America. Human emissions of mercury, mostly from mining, smelting, and coal-burning, are currently rising, predominantly from Asia. The transport of mercury from Asia to northwestern North America may pose an emerging ecological and health hazard, contributing to already high levels of mercury in rivers and fish. However, in order to assess the impact of rising mercury pollution on the ecosystem, it is essential to also determine natural mercury levels through time, derived from volcanism, weathering, and forest fires. The Prospector Russell Col (PRCol) ice core, collected from the summit of Mt. Logan in the Yukon Territory of Canada in 2001 and 2002, is ideal for this study because of its location downwind from Asian pollution sources and its well-dated record spanning the past 17,000 years. This study will use clean sampling techniques and state-of-the-art analysis methods to measure mercury concentrations in the PRCol ice core at 1 to 100-year time scales. Mercury concentrations in this ice core will be compared to records of volcanic eruptions, forest fires, dust, and climate to determine the controls on natural changes in mercury levels. The impact of human mercury pollution on this region will be determined by comparing the concentrations of mercury deposited during the 20th century to concentrations deposited during the prior 17,000 years, before large-scale human mercury pollution. The influence of climate patterns such as El Nino on mercury transport and deposition will be investigated by comparing climate parameters and mercury concentrations during the 20th century.Determining the magnitude and trend of recent mercury contamination is a fundamental step in addressing the global issue of mercury pollution in the environment. Results of this research will be disseminated through academic publications and conferences. An undergraduate research assistant will be trained to assist in this research and to complete a related sub-project. The PIs will do outreach at local middle schools about their research, combining it with discussions of careers in the geosciences. International collaboration will be established through close work between the PIs and the Canadian researchers who collected and have already done some analysis of data derived from the ice core. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising graduate student to establish an independent researchcareer.