辽东湾西北部海域表层沉积物重金属含量的空间分布特征与污染状况评价

Distribution characteristics and pollution evaluation of heavy metals in surface sediments in the Northwest of Liaodong Bay

对2013年秋季和2014年春季两季辽东湾西北部海域共26个采样站位7种重金属含量的分布特征进行了研究。结果表明:该海域表层沉积物中Hg、Zn和Cd含量的平均值均高于渤海工业化前沉积物重金属背景值。单因子污染指数和重金属地质累积指数评价结果显示,Cd属于“轻度”污染,Hg、Cu、Pb、Zn、As和Cr属于无污染程度。重金属潜在生态风险评价结果表明,研究区的综合潜在生态风险“较低”。单金属潜在危害系数程度较高的是Cd、Hg。表层沉积物中重金属和TOC相关性分析表明:TOC含量与重金属Hg、Cu、Cd、Cr和As含量具有一定的正相关性。进一步通过主成分分析表明该海域沉积物重金属有3个来源,即有机质降解;工业废水、城市排污及养殖自身污染;岩石的自然风化和侵蚀过程。本研究结果揭示了辽东湾西北部海域沉积物中重金属的分布特征,初步推断了重金属污染来源,可为辽东湾海洋生态环境保护、修复提供依据。

Seven heavy metals(Cu,Pb,Zn,Cd,Cr,Hg and As)in surface sediments from 26 sites in the northwest waters of Liaodong Bay in autumn of 2013 and spring of 2014 were investigated.The results showed that the concentrations of Hg,Zn and Cd were higher than the background values of Bohai.Marine sediment quality was evaluated with the single factor pollution index method.The results showed that the average value of Hg,Cu,Pb,Zn,Cd,Cr and As conformed to the first-class standard of marine sediment quality.The geo-accumulation index of Hg,Cu,Pb,Zn and Cr were in zero level,and Cd were low.The potential ecological risk of Cd was in middle level and Hg,Cu,Pb,Zn,Cr and As were low.The potential ecological risk of heavy metals was relatively low.Positive correlation was observed between concentrations of 5 heavy metals(Hg,Cu,Cd,Cr and As)and TOC,respectively.Result of principal component analysis showed that the three main sources of heavy metals in marine sediments were industrial wastewater,urban sewage and aquaculture pollution itself,degradation of organic matter and erosion of rocks.This article revealed the distribution of the heavy metals in the northwest of Liaodong bay in order to provide scientific basis for marine sustainable development and marine ecological civilization construction.