海河干流、大沽排污河沉积物中重金属污染及潜在生态风险评价

Evaluation on the potential ecological risks of heavy metal pollution in sediments in the main course of Haihe River and Dagu Drainage Outlet

采用单因子指数法和Hakanson生态风险指数法,分析了海河干流、大沽排污河沉积物中典型重金属污染物的质量比,评估了沉积物中重金属的污染程度,定量确定了其潜在生态风险程度。结果表明,综合污染程度海河干流比大沽排污河严重。海河干流、大沽排污河沉积物当中的典型重金属污染物的平均综合污染指数Cd分别达到20.89和12.47。海河沉积物中重金属的污染程度依次为Zn、Cu、Pb、Cr、Cd,其中Zn的污染最为严重,平均污染指数Cif达到11.24。而大沽排污河中重金属的污染程度依次为Zn、Cr、Cu、Cd、Pb,其中Zn污染较高,Cu、Cr、Cd均为中等污染。大沽排污河比海河潜在生态风险严重,除Cd在两条河流中均具有中等潜在生态风险,其他重金属均具有低等潜在生态风险。

The article intends to present the authors＇ investigation and evaluation of the potential ecological risks due to the heavy metal pollution in the sediments in the main course of Haihe River and the Dagu Drainage Outlet. Our investigation and analysis help us to find that the contents of the typical heavy metal pollutants in the sediments of the two rivers are Cu, Pb, Zn, Cd and Cr. Applying the index techniques of single factor and Hakanson ecological risk to our analysis, we have worked out the actual contamination of heavy metal pollutants to the sediments of the two rivers in hoping to quantitatively determine the potential ecological risks of both rivers caused by the contamination. As a result, the order of integrated pollution degrees proves to be Haihe River 〉 Dagu Drainage River. The average integrated index value of typical heavy metal pollutants Cd stands： 20.89 for Haihe River and 12.47 for Dagu Drainage Outlet, respectively, which indicates that heavy metal pollution in Haihe River and Dagu Drainage River are very serious. The pollution degrees of heavy metal pollutants in sediments of Haihe River indicate the following order： Zn 〉 Cu 〉 Pb 〉 Cr〉 Cd,with Zn pollution being most serious and the average pollution index number being 11.24. More particularly speaking, the order of pollution degrees of heavy metals in sediments of Dagu Drainage Outlet stands： Zn 〉 Cr 〉 Cu 〉 Cd 〉 Pb. Thus, the evaluation results show that Zn pollution proves more serious while pollution of other heavy metals seems moderate. The order of the potential ecological risk likely to be brought about is Haihe River 〈 Dagu Drainage Outlet. But for the moderate potential ecological risk likely to be brought by Cd to the two rivers, other heavy metal pollutants may seem to have lower potential ecological risk.