南沙河表层沉积物重金属污染评价及来源解析

Pollution Evaluation and Source Identification of Heavy Metals in Surface Sediments of Nansha River

测定了南沙河表层沉积物中重金属含量,采用地累积指数法对沉积物中重金属污染程度进行评价,沉积物的重金属地累积指数分级为0~4级,属于无污染至偏重度污染水平,各重金属的污染程度为：Zn〉As〉Se〉Cu〉Pb〉Sb〉Ni〉Cr〉Co〉V〉Tl。运用主成分分析法对沉积物中重金属污染来源进行解析,结果表明,南沙河底泥中不同重金属来源存在着差异,其中Se、Tl、Zn、Cu主要来自矿石开采;V、Cr、Co、Ni主要由冶金锻造支配;As主要来源于燃煤源。PCA的聚类分析指出,本次研究中所调查的13个采样点在污染程度上可分为5大类。

Contents of heavy metals in surface sediment of Nansha River were determined. Index of geoaccumulation of heavy metals in sediment was assessed, and results showed that the index of geoaccumulation which was classified as degrees 0-4 indicated the contamination levels from non to partial serious pollution, with the ranking of various heavy metals pollution from high to low in turn as Zn, As, Se, Cu, Pb, Sb, Ni, Cr, Co, V and T1. Results of principal component analysis （PCA） showed that heavy metals in the sediments came from different sources, with Se, TI, Zn and Cu mainly from ore mining while V, Cr, Co and Ni mainly controlled by metallurgy and forge, As from coal burning in industries. Cluster analysis of PCA indicated that 13 sampling stations could be divided into 5 groups at the pollution degrees.