Analysis of water quality variation and reason of Xiali River pollution of Dingnan River of Dongjiang River

Dongjiang River source zone has become the national ecological compensation pilot zone and the typical pilot zone of water resources protection plan in the Pearl River Basin.The water quality characteristies change is analyzed from the current situation of water quality,water quality evolution trend and main pollutants in the water function zone by the integrated use of single factor index method,average pollution index method,seasonal Kendall test method and the equal standard pollution load method,based on the 2003 ~2014 water quality monitoring data and the 2013 sewage drainage survey data of Xiali River of Dingnan River of Dongjiang River.The results show that the water quality of drinking water source zone is clean,reserved zone is heavy pollution,industrial water utilization zone is serious pollution.It was demonstrated that the ammonia nitrogen,chemical oxygen demand,PH value,arsenic and total phosphorus etc. are the main contaminants of the river.Rare earth smelting,agricultural development,waste water drainage of sewage treatment plant are ther main reason of the river pollution.Finally,the corresponding measures for ecological regulation is proposed.