长江河口溶解态重金属的分布和行为

通过1999年春、夏季对长江口的现场观测,探讨了该处溶解态重金属（Cu、Pb、Cd）在潮汐等水动力因素作用下的分布行为,研究发现：溶解态Cu、Pb和Cd在长江口呈现出非保守行为。低盐度区溶解态Cu、Cd呈现出除去行为,Pb呈现出添加行为,较高盐度区则恰好相反。溶解态重金属含量枯水期比丰水期高,枯水期总体表现为大潮高于小潮,丰水期溶解态Cd也是大潮高于小潮,Cu、Pb则大致表现出小潮高于大潮。通过资料对比,发现近20年来溶解态Cu、Cd和Pb均有不同程度的增加。长江径流量和输沙量的减少,将对上海沿岸水域生态环境产生影响。

Distribution and Behavior of Dissolved Heavy Metals in the River Yangtze Estuary

Distribution and behavior of dissolved Cu, Pb and Cd in River Yangtze estuary have been discussed, according to the survey conducted in Spring and Summer, 1999. The results showed that the dissolved Cu, Pb, Cd exhibited non-conservative behavior in the River Yangtze estuary. The concentrations of dissolved heavy metals were higher in dry season than in flood season. The concentrations of dissolved heavy metals of the spring tide were higher than that of the neap tide in dry season; so did the dissolved Cd, but Pb, Cu presented approximately higher value in the neap tide. Estuarine chemical processes are intrinsic factors to influence the behaviors of dissolved metals, in the extrinsic factors the runoff and tide current are major, but the circular flow and the sediment transport are also very important.The concentrations of dissolved Cu, Pb and Cd were increased at different extent in the last twenties. The decrease of the runoff and suspended sediment transport of River Yangtze may influence on the ecosystem and environment along the coast of Shanghai.