长江中下游河流沉积物和悬浮物中金属元素的形态特征

Metal speciation in sediments and suspended matter in the middle-lower reaches of the Changjiang River

采集长江中下游８个样点沉积物和悬浮物样品，用连续提取方法提取金属元素的５种化学形态（可交换态、碳酸盐结合态、铁锰氧化物结合态、有机质－硫化物结合态和残渣态），用等离子体发射光谱（ＩＣＰ－ＡＥＳ）分析所有样品中锂、钠、钾、镁、钙、锶、钛、钒、铬、锰、钴、镍、铝、钇和锆共１５种元素各化学形态的含量，并用聚类分析方法研究这些元素在形态上的分类特点。结果表明：在沉积物和县浮物中，碱金属元素（锂、钠、钾）主要以残渣态和可交换态存在；碱土金属元素（镁、钙、锶）各形态含量较为均匀，但钙的碳酸盐态含量很高；锰和钴的铁锰氧化物态含量较高；铁族元素除锰和钴以外（钛、钒、铬、镍）、铝和锆残渣态含量高、其它形态含量低。所研究元素中，钙和锰的残渣态含量最低。

Sediments and suspended matter samples at 8 locations in the middle-lower reaches of the Changjiang River were taken in 1992. Five forms(exchangeable, carbonate, organic, Fe/Mn oxide and residual fractions) of metals were extracted by Tessier method. The contents of the five forms for 15 metal elements (Li, Na, K, Mg, Ca, Sr, Ti, V, Cr, Mn, Co, Ni, Al, Y, and Zr) were determined by ICP-AES, and cluster analysis was applied to the classification of the elements. Alkaline metals(Li, Na, and K) exist mainly in residual and exchangeable forms. Alkaline-earth metals(Mg, Ca, and Sr) distribute rather evenly among the five forms , but Ca has a very high proportion of carbonate form. Mn and Co have a high proportion of Fe/Mn oxides bound form. The iron family(Ti, V, Cr, and Ni, except Mn and Co) , Al , and Zr have very high contents of residual form, and very low contents of the other forms. Furthermore, Li has relatively larger proportions of Fe-Mn oxide and organic forms than Na and K. Among all the elements studied, Ca and Mn has the smallest proportion of residual form.