北京城近郊区地下水质特征与污染研究

目前,北京平原区地下水总体较好,局部地下水污染主要集中在城近郊区。通过研究表明,地下水的污染程度、范围与地下水的赋存条件、开采利用状况有密切联系。通过对历史资料的系统分析,查明其污染发展过程可划分为四个阶段:水质自然状况、水质污染缓慢发展阶段、水质污染加快阶段和趋于稳定阶段。目前北京在城近郊区地下水质逐渐趋于稳定。北京城近郊区地下水污染主要是工业、生活以及排污河渠等污染源的影响,其污染的程度．分布范围还与地区包气带岩性、结构、厚度有关,含水层的岩性及地下水流场控制着污染物的迁移。

Character of Groundwater Quality and Investigation of Pollution in the Suburban Districts of Beijing

So far, the overall conditions of groundwater are relatively good in the plain areas of Beijing, and the locations of contaminated groundwater are mainly concentrated in the suburban districts. Investigations indicate that the extent and range of the polluted groundwater are closely related to the exploitation and natural storage conditions of groundwater. After a systematic analy-sis of historic data, the phylogeny of groundwater pollution can be divided into four phases: (1) natural conditions of water, (2) slow pollution of groundwater, (3) accelerated pollution of groundwater, and (4) equilibrium condition. At the present time, the quality of groundwater is reaching the equilibrium condition phase in the outskirt areas of Beijing City. The groundwater contamination in Beijing is mainly caused by industrial and consumer wastes and sewage channels. The range and extent of the contamination are also related to the thickness, struc-ture and type of local vadose zones. Furthermore, the migration of contaminants is controlled by the lithology of the aquifers and flow fields of groundwater.