长江口最大浑浊带悬移质、底质微量金属形态分布

Speciation of Trace Metals in Suspended Particles and Surface Benthic Sediment in the Maximum Turbidity Zones of the Changjiang Estuary

本文用Ｔｅｓｓｉｅｒ分离方法分析了长江口最大浑浊带洪、枯季悬移质和表层底质样品中Ｃｄ，Ｃｕ：，Ｐｂ和Ｚｎ的形态分布，结果表明：Ｃｄ主要以非残渣态存在，占总量９０％左右，其中铁锰氧化物结合态占多数，其次为碳酸盐结合态和离子交换态；Ｐｂ在非残渣态中比例约有７４％，其中铁锰氧化物结合态占近一半，Ｃｕ和Ｚｎ约有６０％以非残渣态存在。其中有机态Ｃｕ比例较高。离子交换态的Ｃｕ和Ｐｂ接近为零．悬移质中微量金属不仅存在洪、枯季变化，而且存在空间变化，涨憩时南槽高于北槽，而落憩时则相反。表层悬移质微量金属含量沿南，北槽向海有递减趋势。总量变化与非残渣特别是铁锰氧化态和有机态的变化有良好的相关性。

By means of the Tessier's procedure of extraction, the speciation of Cd, Cu, Ph, and Zn in suspended solids and surface benthic sediment, collected in the Changjiang Estuary in flood and dry seasons of 1988, were analyzed. The results show that: these trace metals exist mainly in non-rtesidual form, which make up 90%, 74%, 60% and 60% of the total amount for Cd, Cu, Ph and Zn respectively. In the non-residual form, the proportion of trace metals with Fe-Mn oxide is higher than any other forms except Cu, which with organic form is relatively higher. The percentage of exchangable form for Cu and Ph is almost zero. The temPOral and spatial variance of trace metals with Fe-Mn oxide and organic forms has a direct bearing on their total amount in solid phase.