江苏近岸海域沉积物重金属来源及风险评价

摘要

基于2013年江苏近岸海域表层沉积物Cu、Cr、Zn、Pb、Cd、Hg、As重金属调查结果,应用地累积指数法和Hakanson潜在生态风险指数法评估其生态风险,并结合同步调查得到的总有机碳(TOC)、粒径等参数,应用相关性分析和主成分分析方法,探究调查海域重金属的污染特征及来源.结果表明:江苏近岸海域表层沉积物重金属Zn、Pb、Cd、Hg含量均满足国家第一类海洋沉积物质量标准,9.38％、6.25％、6.25％站位的Cu、Cr、As超过国家第一类海洋沉积物质量标准,但满足国家第二类海洋沉积物质量标准;重金属污染程度由高到低顺序为:Cr＞As＞Pb＞Hg＞Cd＞Cu＞Zn.调查海域综合潜在生态风险整体处于较低水平,重金属单因子生态风险由高到低为Hg＞Cd＞As＞Pb＞Cu＞Cr＞Zn,Hg为主要生态风险贡献因子.各类重金属含量均与TOC含量成显著正相关,而与粒径呈现明显的负相关.该海域Cu、Cr、Zn、Pb、Cd具有相近来源,主要为人类工业生产与生活污染,As主要来源于农业污染,Hg则主要来源于有机质降解.%The contents of heavy metals in surface sediment samples collected from the coastal areas in Jiangsu province in 2013 were measured and their ecological risk were assessed with the Hakanson's potential ecological risk index and Geo-accumulation index,respectively.Together with measurements of these samples in total organic carbon (TOC) and particle size,the characteristics and sources of the selected heavy metals were also discussed with an approach of multivariate statistical analysis.The results showed that the contents of Zn,Pb,Cd and Hg in surface sediments were less than China's national first-class benchmark (CFCB) in marine sediment quality.The 9.38％ of Cu,6.25％ of Cr and 6.25％ of As samples were high than CFCB,respectively,but less than the China's national second-class benchmark (CSCB).The contamination in the investigated areas was at a low level on the whole,with an order of the degree Cr＞As＞Pb＞Hg＞Cd＞Cu＞Zn.The potential ecological risks were also at low levels for these metals with a descending order Hg＞Cd＞As＞Pb＞Cu＞Cr＞Zn.Hg was the major contaminant among the metals.The contents of the selected metals were significantly positively correlated with that of TOC,but negatively correlated with particle size.Anthropogenic sewage effluent from industry and residents were the primary agents for Cu,Cr,Zn,Pb and Cd in the sediments,but agricultural source should have contributed to the most of As,and organic degradation accounted for the most of Hg.