杭州市区主要河道水质评价及评价方法的选择

以杭州市7条主要河道21个监测断面1循环年的水质监测数据为依据，运用污染指数法和模糊评价法对市区主要河道水质进行综合评价，同时探讨2种水质评价方法的评价效果.结果表明：①杭州市区主要河道均存在不同程度的污染，主要污染物是TN、NH+4-N和TP，即氮磷营养盐，而有机污染相对较小；②污染指数法评价结果与实际水体的标准差距较小，与真实情况吻合较好；③当水质为劣V类时，模糊评价结论偏保守，而当某项指标严重超标时则易使评价结果偏重；④污染指数法更适合杭州市区河道水环境的评价.

The current situation of water quality in Hangzhou and comparative study of the assessment methods

The data from 21 monitoring intersections of 7 rivers in one cycle year were collected to evaluate the water pollution situation of Hangzhou. The pollution index and fuzzy evaluation methods were applied, and the results from the two methods were compared and discussed. The conclusion indicated that： （1）the rivers were all polluted to some degree, and the predominant pollutants were TN, NH4＋-N and TP, namely the nitrogen and phosphorus, while organic pollution was relatively slight; （2）the evaluation results of pollution index method were closer to the actual water standard and agreed with the real situation better; （3）when the level of water quality was inferior V, fuzzy evaluation results were comparatively conservative, however, when one indicator severely exceeded the standard, the result from this method was more serious; （4）The evaluation results of pollution index method were in accordance with the actual situation of main urban rivers in Hangzhou better.