Water Quality Evaluation for the Rivers on the South Bank of Huaihe River in Anhui Province by the Comprehensive Water Quality Identification Index

The Huaihe River Basin is located in eastern china,between the Yangtze River and Yellow River Basins.Water resource on South bank of Huaihe River in Anhui Province is abundant,with important economic value and ecological value.However,along with the rapid increase of population and development of industry and agriculture,the irrational exploitation of the river caused the deterioration of water resources,the intensification of environmental pollution,the sedimentation accumulation and the decrease of biodiversity,thus making the regional river in serious ecological threat.There are many researches on river water quality assessment in domestic and foreign areas,while lack of studies on the systematic evaluation of the basin as a whole.The water quality of rivers on south bank of Huaihe River in Anhui Province was investigated in the summer of 2010.160 samples were collected from south bank of Huaihe River in Anhui Province,including 4 samples from Sihe river basin,10 samples from Chengxihu river basin,19 samples from Chengdonghu river basin,14 samples from Pihe river basin,41 samples from Wabuhu river basin,18 samples from Gaotanghu river basin, 10 samples from Haohe river basin and 44 samples from Nvshanhu river basin.The monitoring indices included pH,total nitrogen,total phosphate,ammonia nitrogen,nitrate nitrogen,dissoluble orthophosphate and chemical oxygen demand(COD).Selecting total nitrogen,total phosphate,ammonia nitrogen and COD as water quality parameters,the comprehensive water quality identification index(WQI)were used to evaluate the water quality of rivers on the south bank of Huaihe River in Anhui Province.Comprehensive water quality identification index was based on the composition of the single factor index method,which is reasonable and easily applied.The results showed that 77%rivers met the standard;and the main contamination indices were nitrogen nutrient and COD.The main pollution sources were the agricultural non-point pollution and produc- tion and living waste water.The water quality was affected by water flow velocity,sediment properties and the environment around in a certain extent.