威海双岛湾海域重金属的分布特征及生态风险评价

根据2012年双岛湾海域环境调查资料,研究了海水和表层沉积物中重金属的分布特征以及生态风险。结果显示,双岛湾海域海水中的重金属Cu和Pb在湾中部和湾底的部分站位含量较高,Zn和Cr含量在湾底最高、湾外最低,Cd和Hg在湾底和湾外的含量均高于湾中部,As的分布比较均匀;除Zn和Pb外,其余重金属含量均高于周边其他海域。双岛湾海域沉积物中重金属含量较低,与区域背景值相近,其中重金属Hg和Cd在湾内沉积作用明显,而Cu、Pb和Cr在湾外沉积作用比较明显。相关性分析表明,有机碳含量对双岛湾沉积物中的重金属分布影响不大。生态风险评价结果表明,双岛湾海域海水未受到重金属的污染;表层沉积物中重金属存在中低度的生态风险,具有潜在的不利生物毒性效应,重金属毒性大小依次为Pb>As>Cu>Hg>Cr=Cd>Zn。

Distributions and ecological risk assessment of heavy metals in Shuangdao Bay of Weihai

Based on the data of environmental survey of Shuangdao Bay in 2012, the distribution patterns and ecological risk assessment of heavy metals in seawater and surface sediments were analyzed. The results show that the contents of Cu and Pb in seawater are higher in the middle and end of the bay, Zn and Cr are the highest in the end of the bay and the lowest in the external bay, Cd and Hg are the lowest in the middle of the bay, while the distribution of As is uniform. Compared with other estuaries in adjacent area, all heavy metals except Zn and Pb show a higher level. The contents of heavy metals in surface sediments are low, the distributions of Hg and Cd in the mid bay and Cu, Pb and Cr in the external bay are higher than those in other areas. The correlation analysis show that no significant relationship is found between organic carbon and heavy metals in surface sediments. The ecological risk assessment indicates that the pollution of heavy metals in seawater is in the lowest level, the surface sediments has low to medium potential for biological toxicity effect, the sequence of ecological risk intensity caused by different heavy metals is Pb>As>Cu>Hg>Cr=Cd>Zn.