门头沟区地表水水质现状评价及趋势分析

北京市城市总体规划将门头沟区确定为生态涵养发展区,加强生态建设成为实现这一定位的重要途径。因此,了解水质现状及发展趋势尤为重要。为此,以实测资料为基础,对门头沟区河流水质、水库水质以及河流底质现状进行分析,同时采用季节性肯达尔检验法进行水质变化趋势分析。结果表明:门头沟区河流现状水质较好,6个监测点中达到Ⅱ类地表水水质标准的有5个,Ⅱ类水体河长达105.5 km,占监测总河长的88.5%;而2004年对河流底质的评价结果表明:河流底质状况较好,5个监测断面有3个达到一级标准。用季节性肯达尔检验法对7个地表水水质监测点1993—2000年的监测资料的趋势分析表明,水体的总硬度和总氮出现上升趋势,溶解氧、总镉和挥发酚有下降趋势,其他评价项目变化趋势不明显。

SURFACE WATER QUALITY EVALUATION AND DEVELOPMENT TRENDS ANALYSIS OF MENTOUGOU DISTRICT IN BEIJING

In the overall urban planning of Beijing,Mentougou District is orientated to the eco-conserving division.Analyzing the present situation and the trend of the water quality is one of the important thing.According to the monitoring series,the present situations of the rivers,the reservoirs and the river bottom are analyzed.Meanwhile,the trend of the water quality is studied.In the 6 monitoring sites,there are 5 that conform to the Ⅱ grade of surface water quality standard.The river water quality in 2000 is generally in a good condition.But the situation of the river bottom is relatively in a good condition.Among the 5 monitoring profiles there are 3 at the best level.In this study,the materials from 1993 to 2000 of the 7 surface water monitoring sites are analyzed by using the seasonal Kendall test method.The results show that the total hardness and the TN are increasing;the dissolved oxygen,the total cadmium and volatile phenol show the decreasing trend;others are not significant.