Spatio-Temporal Changing Analysis on Water Quality and Pollutants of Hanjiang River

Single-factor evaluation and comprehensive pollution index of water quality are used for water quality and pollution level assessment of Hanjiang River valley based on monthly monitoring data from 2007 to 2009.The results showed that the water quality of Hanjiang River valley is good on the whole and could be divided into four parts along the River flows.In the 19 sections of Hanjiang River main stream,5 sections' pollution level are relatively higher,the reaches between these 5 sections are the main polluted areas.There are 7 key pollution indicators,among which total phosphorus has the highest frequency of appearance,followed by BOD5.The sources and impacts of major pollutants are analyzed from three aspects:the water from tributaries of Hanjiang River,diffused pollution,domestic sewage.