Assessment of Water Environment Quality and Pollution Factors for Dali County

In order to evaluate the groundwater quality and pollution in Dali county,we carried out the field survey and analysis of the water chemistry from 2006 to 2007.Based on the indexes for third-grade water of the N national groundwater quality standard of China,we selected 12 hydro-chemical components which exceed the standard to assess the groundwater environment quality using the fuzzy-grey evaluation model. The result shows that the majority of water fall the Ⅴ type.Further study indicates that the factors affecting water quality are,from great to small,oxide of iron,chloride,total hardness,fluo ride,total dissolved solid,which are the source of bitter salt water.The high contents of oide of iron,total har dness,total dissolved solid,sulfate,halid are deter mined by geological condition and climate of Dali county,while that of COD,nitrate,nitrite,manganese,and chrome pollutant are mainly caused by human behaviors.