Environmental Assessment On Surface Water Quality Of Beijing City

As the water environment is being worse, the pollution of surface water in Beijing has been a great concern. In order to know the current situation of the surface water pollution, water samples were taken from major 5 rivers for chemical analysis. Fuzzy mathematical evaluation method and single index assessment method were adopted to analyze the data. Finally, the strategy of pollution control was presented. The results obtained were as follows:(1) The water quality of Chaobai River was good. Among all the monitoring sections, 41.4% water quality could match class II-III. The downstream pollution was caused by industrial wastewater released from riverbank of Shunyi and Niulanshan wine factory.(2) The water quality of Yongding River was relatively good. 27.3% monitoring sections could match class II~III. The wastewater released from Yanqing, Zhangjiakou and Xuanhua caused the local water degradation.(3) The water quality of Daqing River was bad. From upstream to downstream, the water pollution was obviously getting worse. Pollution style became from single heavy metal pollutant to the inorganic pollutants mixed with organic pollutants. Water pollution might be cause by fertilizer and pesticide from rural enterprises in Shijiazhuang, and wastewater from mining.(4)The water quality of Ji canel was class V or below, and many quality parameter overran standard in downstream sections. The water was polluted mainly by the wastewater in Pinggu and Shunyi.(5) The water quality of Bei canal was below class V, the worst of all. It was the main river for pollutant discharge of Beijing, so it was polluted severely.(6) The lakes could match the water quality criterion. However, except Miyun and Haizi reservoir, all other reservoirs were polluted in a different level, and among these reservoirs, the water qualities of Guanting and Shahe reservoir were the worst.(7)The relativity between nitrogen and organic indexes was wondrously well, the same was between phosphorus and organic indexes, but the relativity between the heavy metals was different. The dependence relation between DO and other indexes was negative correlation. The different relativity of each index indicated that there were commonness and difference in polluting sources.(8) Fuzzy mathematical method could not only present water quality, which was better than water criterions, but also prevent warped only through single pollutant assessment. However by single index assessment method, the threat of drinking water over standard could be avoided, and the percent over standard contamination and its quantity could be known, for easy to analyze the fundamental reason. Both methods should be combined to assess the surface water quality in Beijing.