Collaborative Research: Quantifying Human Forcing of Legacy Sediment and Metal Contamination Dynamics on the Yunnan Plateau of Southwestern China

在全球范围内，过去人类活动造成的金属污染阻碍了人类对环境系统的管理，特别是土壤(农业)和水生系统(饮用水)。管理这些历史污染物的普遍挑战之一是，它们既可以通过风也可以通过水(通常附着在水中的沉积物上)运输。澄清这些运输途径的相对重要性对于成功管理受污染的土壤和防止世界各地未来的土壤退化至关重要。在许多情况下，水-沉积物途径有很大的延误，这些延误给近期污染的风险评估带来了挑战。此外，城市化等最近的活动可以重新动员历史上的污染。该项目以云南中国地区为重点，该地区拥有多个历史时期的金属提取和提纯。通过重建云南空气和水上污染物运输之间相互作用的长期历史，可以检查工业革命期间发生的大量全球金属污染对环境的影响，以及土地利用变化对污染物迁移的影响。这项研究旨在从更长远的角度研究中国西南部的沉积物动力学，并评估湖泊环境中金属聚集的时间、规模、速率和来源。特别是，该项目将三个目标联系在一起：1)定量估计储存在流域土壤中的金属污染物的数量，并利用地球化学混合模型确定其来源；2)通过检查沉积物中记录的历史事件，确定对这些金属污染物的侵蚀、迁移、积累和再分布的控制，特别是人类控制；以及3)记录自然气候变异性与人类活动对湖泊系统金属积累的影响。这些目标结合在一起，提供了测量储存在景观中的污染对所有现代人类系统的风险的手段，并加强了我们对流域累积影响如何影响地球系统的理解。该奖项由地貌学和土地利用动态计划、刺激竞争性研究的实验计划和国际科学与工程办公室共同资助。

Globally, metal contamination from past human activities hinders human management of environmental systems, particularly soils (agriculture) and aquatic systems (drinking water). One of the universal challenges in the management of these historical contaminants is that they can be transported by both the wind and in water (generally attached to sediments in water). Clarification of the relative importance of these transport pathways is fundamental to the successful management of contaminated soils and prevention of future soil degradation worldwide. In many cases, there are substantial delays in the water-sediment pathway, and these delays create challenges in risk evaluation of recent contamination. Further, more recent activities such as urbanization can remobilize historical contamination. This project focuses on the Yunnan region of China, a region with multiple historical periods of metal extraction and purification. Reconstruction of the long history of interactions between the airborne and waterborne contaminant transport in the Yunnan allows examination of the environmental implications of substantial global metal contamination that has occurred with the industrial revolution and the influence of land use changes on contaminant mobilization. This research aims to develop a longer-term perspective of sediment dynamics in southwestern China and assess the timing, magnitude, rate, and source of metal accumulation in lake environments. In particular, the project links three goals: 1) Quantitatively estimate the amount of metal contaminants stored in watershed soils and attribute their source using geochemical mixing models; 2) Identify the controls on erosion, transport, accumulation, and redistribution of these metal contaminants, particularly human controls by examination of historical events recorded in sediments; and 3) Document the influences of natural climate variability versus human activity on metal accumulation in lake systems. When combined, these goals provide the means to measure the risks of contamination stored in the landscape to all modern human systems and enhance our understanding of how cumulative watershed impacts influence our Earth system.This award is cofunded by the Geomorphology and Land-use Dynamics Program, the Experimental Program to Stimulate Competitive Research, and the Office of International Science and Engineering.