中文摘要：

以海河流域北部地区主要河流为研究对象,采用Hkanson潜在生态风险指数法,根据39个采样点评价了河流沉积物重金属的潜在生态风险程度.结果表明,以中国大陆沉积物重金属背景值作为参考值,研究区内除Pb含量接近背景值外,Cu、Zn、Cd和Cr含量均超出了背景参考值.基于单项重金属的潜在生态风险指数,研究区内采样点Cu、Pb、Zn和Cr的风险等级属于＂轻微＂,Cd则有不同程度的污染,各重金属污染等级排列顺序为Cd〉Pb〉Cu〉Cr〉Zn.基于多种重金属的潜在风险指数,32个采样点属于＂轻微＂等级,5个采样点属于＂中等＂等级,2个采样点属于＂很强＂等级.风险较高的河流为北京汤河、大石河和保定拒马河,表明这些河流是需要加强控制的重点地区.

英文摘要：

Using Hkanson potential ecological risk index,the paper assesses heavy metal risk levels in northern parts of Haihe River basin based on 39 sampling sites.The results indicate that,the concentrations of Cu,Zn,Cd,and Cr in Haihe River basin are higher than the background values of heavy metals in China mainland,while the concentration of Pb is close to the background value in China mainland.Based on the potential ecological risk index for single heavy metal,the risk of Cu,Pb,Zn and Cr belongs to the ＂slight＂ level,while Cd has various risk levels at different sampling sites.Generally,the risk order of the heavy metals is CdPbCuCrZn.According to Hkanson potential ecological risk index,32 monitoring sites belong to ＂slight＂ level,5 sampling sites belong to ＂middle＂ level,and 2 monitoring sites belong to ＂very strong＂ level.The most polluted sites are Tang River and Dashi River of Beijing,Juma River in Baoding.Therefore,these rivers should be taken more considerations in the river management.