北京东南城区雨水化学特征与化学稳定性分析

为了给北京市城区雨水利用提供基础数据.基于近几年北京东南城区17场典型的自然降雨和不同下垫面径流雨水水质检测结果,分析了雨水的水质特性及其化学稳定性.研究结果表明,北京东南城区自然降雨和地表径流雨水水质为重碳酸盐钙组Ⅰ型;雨水水质已经受到一定程度的污染,主要污染物为有机物和含氮化合物;雨水的pH值与雨水中碱性粒子浓度呈显著的正相关性;水的稳定性主要受CaCO_3溶解沉淀过程控制,除机动车道径流雨水为沉积性水质外,自然降雨和其他地表径流雨水多呈侵蚀性.因此,在城区雨水利用过程中应注意雨水水质污染和工程设施侵蚀的问题.

Chemical Characters and Stability Analysis for the Rainwater in Southeast Region of Beijing City

Based on the test results of water quality for seventeen times rain and rainfall in Southeast Region of Beijing city,it was conducted for a comprehensive water quality investigation of the rain-water and rain-runoff in the area,including characterization of their chemical properties and analysis of the water stability.The in- vestigation results show that the collected rain-water and surface runoff water are soft and Type-Ⅰwater within the category of bicarbonate calcium.The results also show that the pH is well related with alkaline par- ticles in the rain-water and runoff water within this area.It indicates that the rain-water and runoff water within this area have been contaminated to a certain degree by a nitrogen-compounds or a hydrocarbons from intensive human activities.Water stability analysis in this study focuses on its potential of precipitation and dissolution,in which carbonate calcium (CaCO_3)plays a dominant role.The results show that only runoff water on traffic roads prefers to precipitate while rain-water and other runoff water in the areas are character- istic of their solubility.Therefore,the problems of polluted rain-water and engineering installations corrosion should be especially awared of during the rain-water usability.