城郊流域河岸带土壤与河流沉积物的重金属污染及分布特征——以温榆河昌平段为例

Heavy Metal Pollution and Distribution in Riparian Zone Soil and River Sediment in Beijing Suburbs,China:A Case Study in Changping Section of Wenyu River

位于京郊的温榆河流域河岸带及河流受周边人类活动影响污染严重,为了解该流域的重金属污染和分布特征,采集了温榆河昌平段河流岸边溪水中表层沉积物及河岸带不同土壤层样品,测定了样品中Cu、Zn、Pb、Cr4种重金属的含量,并利用相关性分析及回归分析,分析不同深度河岸带土壤与沉积物中重金属的相互关系。结果表明,沉积物中Zn、Pb含量显著高于河岸带土壤中的含量,而Cu含量显著低于河岸带土壤中的含量;与北京市土壤重金属背景值相比,河岸带土壤与河流沉积物中4种重金属均存在一定程度的累积,其中以Cr元素累积指数和超过背景值的样本概率最高。河岸带表层土壤(0～20cm)与河流沉积物重金属空间分布具有显著的规律性,在工厂废水、生活污水排污口及人类活动干扰频繁的取样点污染严重。河岸带土壤中Cu与Zn、Cr含量、沉积物中Zn与Cu、Pb含量以及河岸带土壤中Pb、Cr与沉积物中对应元素存在显著正相关(P<0.01)关系,同时河岸带土壤中Pb、Cr含量分别与其在沉积物中含量存在显著的回归关系。研究结果表明河流岸边带土壤与河流沉积物的重金属污染存在着依存关系,加强岸边带的土壤污染治理将一定程度缓解河流水环境的重金属污染。

To explore the heavy metal concentration and distribution in the Wenyu River in Beijing Suburb, a survey was conducted by col- lecting and analyzing the surface sediment and riparian zone soil there. Such heavy metals as Cu, Zn, Pb and Cr were examined and the corre- lation of the content of heavy metals in sediment and riparian zone soil in different layers were also determined. The results indicated that the content of Zn and Pb in the sediment was significantly higher than that in the soil while the content of Cu was significantly lower than that in the soil. Compared with the background value in Beijing soil, Cu, Zn, Pb and Cr were all enriched to certain degree, especially Cr. The spatial distribution of heavy metals in surface soil and sediment had the remarkable regularity, and the sampling point pollution was serious due to factory sewage, waste water drainage outlet and human frequent disturbance. The correlation analysis showed that the content of Cu with Zn, Cr in riparian zone soil and the content of Zn with Cu and Pb in sediment had a significant positive correlation（P〈0.01 ）. In addition, there was significant correlation（P〈0.01 ） between Pb and Cr in soil and those in sediment. The content of Pb and Cr in riparian soil and that in sediment had strong regression relationship. The results revealed that heavy metal pollution in riparian zone soil and pollution in sediment were closely related, and therefore to strengthen the soil pollution control might help to alleviate the heavy metal pollution in water environ- ment.