珠江口荷包岛近岸海域沉积物重金属分布及其潜在生态危害评价

Distribution features and evaluation on potential ecological risk of heavy metals in surface sediments nearby Hebao Island,Pearl River Estuary

本文采用2008年在珠江口荷包岛近岸海域的调查数据,对表层沉积物重金属的分布特征及重金属与TOC的相关性进行了分析,并采用Hakanson潜在生态危害指数法对其生态危害程度进行了评价。结果表明:重金属Cd,Hg,Cr和As四种元素分布基本呈现荷包岛近岸海域较高的特点,重金属Zn,Pb和Cu的分布没有明显规律;重金属富集顺序为Cd>Zn>Cu>Hg>As>Cr>Pb。相关性研究表明,重金属Cu与Zn显著相关,Hg,Cr,Cd和As极显著相关;有机质是影响沉积物重金属迁移和转化的重要因素。潜在生态危害评价结果表明,荷包岛近岸海域表层沉积物重金属总体潜在生态危害轻微;各重金属生态危害程度顺序为Cd>Hg>As>Pb>Cu>Cr>Zn;对荷包岛近岸海域生态环境具有潜在生态危害的重金属主要是Cd和Hg。

The distribution and enrichment of the heavy metals in surface sediments nearby Hebao Island, Pearl River Estuary were studied, the correlation among the heavy metals （Cu, Zn, Pb, Cd, Hg, As, Cr） and the contents of TOC in the surface sediments were also analyzed. In addition, the method of potential ecological risk index presented by Lars Hakanson was used to assess the heavy metals＇ ecological risk. The results show that the contents of Cd, Hg, Cr and As appear higher nearby Hebao Island , while those of Zn, Pb and Cu has no apparent rule. The order of the enrichment of heavy metals is Cd^Zn~〉Cu^Hg~〉As~〉Cr 〉Pb. The correlation analysis indicates that Cu significantly correlated with Zn, while As, Hg, Cr and Cd all have highly significant correlation; the organic matter is an important influencing factor of the migration and transformation of heavy metals. The assessment results of heavy metals＇ ecological risk reveal that Cd and Hg belong to middle potential ecological risk, while other heavy metals belong to light potential ecological risk. The order of potential ecological risk factors is Cd〉Hg〉As〉Pb〉Cu〉Cr〉Zn.