海河流域中部表层沉积物中重金属分布特征及污染评价

为了解海河流域中部表层沉积物中重金属分布特征和污染现状，分别测定了17个采样点表层沉积物中Cr、Ni、Cu、Zn、As、Cd、Hg、Pb共8种重金属元素质量比，并采用相关性分析法、富集系数法、地累积指数法分析其同源性、污染来源及污染程度。结果表明：海河流域中部表层沉积物中重金属质量比整体上较历史水平有所下降，8种重金属元素的污染系数从高到低依次为Cd（1-98）、Hg（1-80）、Cu（1-37）、Zn（1-18）、Pb（1-12）、Ni（1-07）、Cr（1-02）、As（0-77），Cd污染相对严重；Cd和Hg的富集系数平均值均高于1-5，污染来源以人为输入为主，其余6种重金属元素则主要以自然来源为主；海河流域中部重金属总体上污染较轻，个别点位污染等级达到中度污染。

Distribution characteristics and pollution assessment of heavy metals in the surface sediments in the middle of Haihe River Basin

In order to understand the distribution characteristics and pollution status of heavy metals in the surface sediments in the middle of Haihe River Basin, the mass ratios of Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in the surface sediments of 17 sampling sites were determined. The homology, pollution source and pollution degree were analyzed by correlation analysis method, enrichment coefficient method and geoaccumulation index method. The results show that the heavy metal mass ratios in the surface sediments in the middle of Haihe River Basin generally decreased compared with the historical level and the pollution coefficients of eight heavy metals were Cd(1. 98), Hg(1. 80), Cu(1. 37), Zn(1. 18), Pb(1. 12), Ni(1. 07), Cr(1. 02)and As(0. 77)from high to low, wherein Cd pollution was relatively serious; The average enrichment factor values of Cd and Hg were higher than 1. 5 with the pollution source mainly from human input, while the rest six heavy metals were mainly from natural sources. The pollution of heavy metals in the middle of Haihe River Basin was relatively light in general with moderate pollution levels at some sites.