燕尾港近岸海域表层沉积物重金属的分布与污染评价

摘要

Heavy metal (Cu ,Zn ,Pb ,Cd ,Cr ,As ,Ni ,and Mn) concentrations and geo-accumulation index (Igeo) were determined in surface sediments in Yanwei harbor to understand the pollution status of the study area based on the background values .Results showed that the average concentrations (mg/kg) in the surface sediments were found to be 20 .2 for Cu ,264 for Zn ,54 .0 for Pb ,1 .52 for Cd ,69 .8 for Cr , 38 .8 for As ,35 .7 for Ni ,and 684 for Mn ,the contents of Cu ,Zn ,Pb ,Cr ,and As being within the relevant national standard in terms of heavy metal contamination ,and Cd being beyond the standard .The gIgeo revealed that there was Cd contamination in the entire study area ,with a descending order as Cd>As>Pb>Zn> Cr> Ni> Cu .Principal component analysis (PCA ) and cluster analysis showed that the heavy metal contamination was derived from industrial effluent ,agricultural wastewater and atmospheric sedimentation ,the former two accounting for 62 .41% ,and 12 .52% ,of the total variance .%测定了燕尾港近岸海域表层沉积物中重金属的含量，运用地累积指数就其污染程度进行了分析与评价。结果表明Cu、Zn、Pb、Cd、Cr、As、Ni、Mn的平均含量分别为20．2，264，54．0，1．52，69．8，38．8，35．7，684 mg/kg。Cu、Zn、Pb、Cr、As的平均含量低于国家海洋沉积物质量标准的二级标准值，重金属Cd的平均值高于国家海洋沉积物质量标准的二级标准值；地累积指数评价结果表明，Cd在调查海域污染程度重，7种重金属的污染程度依次为Cd＞ As＞ Pb＞Zn＞Cr＞Ni＞Cu。对结果进行主成分分析和聚类分析后发现，前2个主成分的贡献率分别为62．41％、12．52％，表明此海域表层沉积物中重金属的主要来源是工业废水和农业灌溉水的排放及大气沉降。