Comprehensive evaluation and trend analysis for water quality of Dianchi Lake

Dianchi Lake is one of the key lakes that are under environmental improvement in China.The water quality status of Dianchi Lake(in 2010) is analyzed based on the data of 8 sampling and monitoring points for Dainchi Lake.The water body pollution degree evaluation is conducted by adopting the mean-value comprehensive pollution index method.Based on the monitoring data from 2001 to 2010,the follow indexes are selected: ammonia nitrogen,total nitrogen,index of permanganate,5d biochemical oxygen demand,total phosphorus,and water quality trend analysis was conducted by seasonal Kendall method.The results show that the water is classified as poorer V,the ammonia nitrogen,total phosphorus are the most serious pollutants,and the total nitrogen,5d biochemical oxygen demand are in a deterioration state,but the index of permanganate has no obvious change.