Water quality analysis and eutrophication assessment on lakes in Taihu basin
太湖流域主要水系水环境特征分析与富营养化评价

Aimed at characterizing the water quality,identifying the key influencing environmental factors and evaluating the eutrophication in terms of fuzzy assessment model,we investigated water quality at 32 sites of the five water systems(Rivers Tiaoxi,Nanxi,Yanjiang,Huangpujiang and Taihu Lake) within Taihu Basin.The results showed that SD all were very low except rivers Tiaoxi and Nanxi,which may be related with the high levels of inorganic particles,but the content of algae,organic matter,hydrodynamic conditions etc may also be the important factors affecting SD.Oxygen-consuming organic pollutants in Taihu Lake Basin were at the surface water Ⅳ to Ⅴ class level,and the value of B/C was relatively high,which means organic pollutants were easy to be used by microorganisms,therefore causing the rapid decline of DO in water.Nutrients pollution was relatively serious.TN and TP were at the surface water Ⅴclass level,and TP was the most prominent factor in five river systems.DIN and PO3-4 were the main form of TN and TP,and the high concentration of them provided the conditions for algae growth.Principal component analysis showed that TN,TP and oxygen-consuming organic pollutants were the major contributors to water pollution in Taihu Basin.Fuzzy assessment results showed that the river systems of Tiaoxi,Nanxi and Taihu were in middle eutrophication state and the river system of Yanjiang and huangpujiang were in high eutrophication state.