湄洲湾海域表层沉积物重金属含量的分布特征及潜在生态风险评价

根据2012年福建湄洲湾海域表层沉积物样品测定的7种重金属（Cr、Co、Ni、Cu、Zn、As、Pb）含量数据,研究重金属在沉积物中的含量和空间分布特征,然后运用主成分分析法分析各重金属的主要来源,最后采用潜在生态危害指数法评价其污染程度和潜在生态危害.结果表明,相对第一类海洋沉积物标准,Cu、Zn、As和Pb含量均未超标,Cr超标21.2%.大部分重金属含量平面分布总体呈现东北往西南递减的趋势,体现陆源输入的影响,As、Zn及Pb在7号站位、Cu在8号站位出现高值区可能更多地联系于研究区域本身的背景特征.Cr、Co、Ni和Zn含量之间相关性显著,且Co、As和Zn含量也两两表现出显著正相关.主成分分析表明岩石的自然风化和侵蚀是Cr、Co、Ni、Cu、Zn和As元素在研究区域表层沉积物的主要来源,Pb可能更多来源于海上交通航运和海水养殖.研究区域综合潜在生态危害为中等生态危害程度.

Content distribution characters and potential ecological risk assessment of heavy metals in surface sediments of Meizhou Bay

Based on data of heavy metals in surface sediments of Meizhou Bay in 2012,this paper first analyzed the content,characteristics and spatial distribution of heavy metals（Cr,Co,Ni,Cu,Zn,As,Pb）.The sources of heavy metals were studied by principle component analysis（PCA）.Finally,their potential ecological risk was assessed through the potential ecological risk index.The results showed that the average content of Cu,Zn,As and Pb were qualified by the first class of marine sediment quality,but surpassed by 21.2% for Cr.The content of most heavy metals decreased from the northeast to the southwest of study area,which was obviously caused by the land source input,but sediment background maybe the main source of As,Zn and Pb at station 7,and of Cu at station8.Strong correlations existed among Cr,Co,Ni and Zn.Co,As and Zn also had significant positive correlations in every two elements.Principle component and background valves analysis showed that rock weathering was the dom-inant source of Cr,Co,Ni,Cu,Zn and As,while Pb was mainly related to the marine traffic and mariculture.The comprehensive potential ecological risk was evaluated as median in the studied areas.