北运河底泥污染物评价及资源化利用研究

Study of the Sediment Pollutant Evaluation and Resource Utilization in the North Canal

为了解北运河底泥物理性质和污染程度,采用柱状取样设备,在北运河断面开展现场底泥采集,测定底泥物理性质、营养盐及重金属含量。结果表明:有机质、总氮和总磷平均值分别为30.39 g/kg、0.161%和0.174%,参照评价标准,分别为一级断面、三级断面和四级断面。重金属Cd、Cr、Ni、Zn、Cu、Pb、As平均值分别为0.39、86.55、29.09、199.82、52.27、33.86、8.26 mg/kg,均超过北京市土壤重金属背景值,地累积指数法评价结果表明,上游段重金属偏中度污染,其中Cd和Zn为中度污染;中下游段为轻度污染。重金属平均含量处于轻度污染以下,污染程度不严重。底泥满足农用地回用和筑堤材料要求,开拓了资源化利用途径。

To understand the physical properties and pollution degree of the sediment in the North Canal,this paper collects the sediment in sections of North Canal with a columnar sampling device,and determines the physical properties,nutrient salt and heavy metal content of sediment.The results indicate that the average value of organic matter,TN and TP were 30.39 g/kg,0.161%and 0.174%,respectively,and were primary section,tertiary section and quaternary section according to the evaluation criterion.The average value of Cd,Cr,Ni,Zn,Cu,Pb and As were 0.39、86.55、29.09、199.82、52.27、33.86 and 8.26 mg/kg,respectively,which exceeded the background values for soil in Beijing.The evaluation results of geo-accumulation index show that the upper reach was partial moderate pollution,among which Cd and Zn were moderate pollution,and the middle and lower reaches were mild pollution.The average content of heavy metals was below the light pollution,so the pollution is not serious.Besides,the sediment can be reused to agricultural land and used as levee material,which exploit the way of resource utilization.