北京市妫水河水质现状评价

Water Quality Assessment for Guishui River in Beijing

2017年分3个时期(丰水期、平水期、枯水期)采集妫水河及其支流12个断面表层水样,分析了COD、氨氮、TP、DO、pH值等水质指标,采用单因子评价法、水污染指数法、主成分分析法和模糊综合评价法对水质进行评价,根据4种水质评价方法的评价结果,分析4种方法在小流域河流评价中的适用性。结果表明:目前妫水河12个断面中S2、S10和Z2 3个断面水质较差,基本属于地表Ⅴ类水,污染程度为重度污染;其他9个断面水质等级为地表Ⅳ类水,污染程度为中度污染;中段世园会段水质较好,优于上段和下段,主要污染指标为COD;妫水河主要污染源于农业和生活,枯水期水质优于平水期和丰水期。水污染指数法更适合小流域水体水质的定性定量评价,且计算方便简单。

The surface water samples from 12 monitoring sections in Guishui River and its tributaries were collected during rainy,normal and dry seasons in 2017,the water quality indexes such as COD,NH 3-N,TP,DO,pH,etc.were detected and evaluated by single factor evaluation method,water pollution index method,principal component analysis method and fuzzy comprehensive evaluation method,and the applicability of these four methods was discussed according to the evaluation results.It turned out that among the 12 sections,the water quality at S2,S10 and Z2 sections was polluted heavily,which belonged toⅤ-grade surface water quality,while the rest 9 sections belonged toⅣ-grade and were moderately polluted.The water quality at International Horticultural Exhibition section was better than that at upstream or downstream.COD was the main pollutant.Agricultural and domestic pollution were the main sources in Guishui river.The water quality in dry season was better than that in normal and rainy seasons.The water pollution index method was more feasible for qualitative and quantitative evaluation of water quality in small watershed,and the calculation was simple.