State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, China.
Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519080, China.
Environ Monit Assess. 2022 Aug 9;194(9):660. doi: 10.1007/s10661-022-10337-9.
High sediment flux in large rivers provide sufficient dilution to the heavy metals' concentration. However, sediment starvation caused by hydrological engineering in recent decades has been reported worldwide. Thus, a study is necessary on the influences of recent declining sediment flux on heavy metal pollution change in the suspended sediments. In this study, heavy metal concentrations and speciation (Cd, Pb, Zn, Cu, Co, Ni, and Cr) in suspended sediments were investigated downstream the Three Gorges Dam (TGD) during dry and flood seasons. Substantial changes of Pb, Zn, Cd, and Cu along the river channel were found which were constrained by the dilution efficiency of suspended sediment during the dry season. High proportion of labile fraction revealed anthropogenic sources of heavy metal. Moreover, the historical trend of metal content illustrated TGD construction together with anthropogenic influx both contribute to the increasing environmental risk in the Yangtze River basin.
大河中的高泥沙通量为重金属提供了足够的稀释度。然而，近几十年来，水利工程导致的泥沙饥饿现象已在全球范围内得到报道。因此，有必要研究近年来泥沙通量的减少对悬浮泥沙中重金属污染变化的影响。本研究在枯水期和丰水期对三峡大坝下游的悬浮泥沙中的重金属浓度和形态（Cd、Pb、Zn、Cu、Co、Ni 和 Cr）进行了调查。在枯水期，悬浮泥沙的稀释效率对 Pb、Zn、Cd 和 Cu 的沿程变化起了限制作用，发现了显著的变化。高比例的可利用分数揭示了重金属的人为来源。此外，金属含量的历史趋势表明，三峡大坝的建设以及人为物质的流入都增加了长江流域的环境风险。
