杭州湾河口地区表层沉积物中重金属的分布特征及污染评价

对杭州湾河口地区南北岸及钱塘江杭州河段15个采样点的表层沉积物中重金属含量进行了测定.结果表明,Cu,Cr,Pb,Zn及Cd含量范围分别为17.0～48.6,24.4～44.1,23.0～55.8,186.8～324.4,0.07～0.60mg/kg.各元素平均含量排序为Zn>Cr>Pb>Cu>Cd.与国内外典型的河口和滨岸带比较,该地区Cu,Cr,Pb及Cd的平均含量处在相对较低的水平,但Zn的污染较为严重.重金属含量沿程分布特征呈现多峰值变化,表明原因较为复杂,受多种环境因素共同影响.地累积指数法及生态风险指数法对重金属污染程度评价结果一致,大多数采样点的Zn处于中度污染水平,Cd及Cu处于轻度污染,Pb及Cr处于轻度污染或较为清洁状态.重金属元素污染程度排序为Zn>Cd>Cu>Pb>Cr.生态风险评价结果表明该地区总体处于低度生态风险等级,其中Cu,Cr,Pb及Zn均为低生态风险等级,而Cd为中度或较重生态风险等级.生态危害程度的排序为Cd>Cu>Pb>Zn>Cr.

Heavy Metal Distribution and Pollution Assessment in the Surface Sediments of Hangzhou Bay

The contents of Cu,Cr,Pb,Zn,Cd in the 15 surface sediments samples from southern and northern coastal areas of Hangzhou Bay,Hangzhou part of Qiantang River were determined. The results indicated that the contents of Cu,Cr,Pb,Zn,Cd ranged from 17.0-48.6,24.4-44.1,23.0-55.8,186.8-324.4,0.07-0.60 mg/kg,respectively. The order of average contents is:Zn>Cr>Cu>Pb>Cd.Compared with heavy metals contents in other coastal areas in the world,the contents of Cu,Cr,Pb,Cd in the study areas were relatively lower,but Zn was higher. The distribution of five heavy metals was complicated and influenced by many environmental factors. The results of pollution assessment by Index of Geoaccumulation and the Potential Ecological Risk Index were almost the same.The order of polluting degree was: Zn>Cd>Cu>Pb>Cr.The assessment result of ecological risk revealed this area belongs to light potential ecological risk. The order of ecological risk is as follow: Cd>Cu>Pb>Zn>Cr.