Abstract:

Water environment is the foundation for aquatic organisms to survival and for fisheries resources to develop sustainably and healthily.The content of heavy metals in water environment is directly related to the quality and safety of aquatic products.To appraise the water environment of typical lakes in the middle reaches of  the Yangtze River,content of heavy metals in water and sediment of the Datong Lake was measured,the pollution of sediment heavy metals was evaluated by the methods of geoaccumulation index and potential ecological risk index,and the pollution and the potential ecological risk of sediment heavy metals for typical lakes in the middle ranches of the Yangtze River were also estimated in the present study.The results showed that the content of As,Cd,Cu,Pb and Zn in water of the Datong Lake all met the water quality standard for fisheries.Except for the content of Zn for S7,S17,S33 and S39 which belonged to the grade II surface water,the content of 5 heavy metals analyzed for all samples was within the range of environmental quality standard for grade I surface water.The content of As,Cd,Cr,Cu,Pb and Zn in sediment of the Datong Lake was all higher than their corresponding background values for the area of the Dongting Lake,which indicated that there was growing tendency of accumulation for above 6 heavy metals in sediment of the Datong Lake.However,the result showed that the pollution arose from heavy metals in sediment of the Datong Lake was still lighter judged by the methods of geoaccumulation index and potential ecological risk index.The pollution resulted from sediment heavy metals in the typical lakes in the middle ranch of the Yangtze River were lower overall, except for several heavy metals in few lakes which showed slight higher pollution.