Contents of Al,Fe,Mn,Zn,Cr,Co,Ni,Cu,As,Cd and Pb in the surface and core sediments of Lake Yangzonghai were determined.Combined with geochronology,the heavy metal spatio-temporal characteristics,the status relative to the pre-in-dustrial levels,and potential ecological risk of the pollution were evaluated by the surface and core sediments from Lake Yangzong-hai.The results showed that metal contents exhibited obviously spatial variations in the surface sediments.Contents of As,Cd,Cu,Pb and Zn were generally higher in the middle-east lake area than those in other areas.In contrast,contents of Cr,Co and Ni showed higher values in the south lake area.Contents of As,Cd,Cu,Pb and Zn in the core sediment had increased gradually since the mid^-1990s and reached the maximum values around the year of 2009-2010,followed by a gradual decline in recent years.Contents of Cr,Co and Ni showed similar temporal variations to the trends of detrital metals (such as Al and Fe),and they decreased generally in recent hundred years.As,Cd,Cu,Pb and Zn in sediments of Lake Yangzonghai were contaminated as indi-cated by the enrichment coefficients,showing that metal contaminations began at the mid^-1990s and reached the maximum values around the year of 2009-2010,but it declined gradually in recent years with the implementation of industrial discharge control.In the surface sediments,Cu was at unpolluted to minimal contamination levels,while Zn and Pb displayed minimal to moderate con-tamination levels.Metal As had moderate to strong contamination levels,and Cd showed minimal to strong contamination levels.The pollution levels of the metals in the eastern lake were higher than those in other lake areas,these are because of a relatively rare runoff,low deposition of detrital materials and high anthropogenic/detrital metal sedimentation.The metals in sediment of Lake Yangzonghai may pose a medium to strong potential ecological risk when compared with a historical pollution peak around 2002-2010.The main contribution factors were Cd and As.Potential eco-risks of the metals decreased in recent years and reduced to the low level except in the east lake area,where the metals may be of a moderate potential ecological risk.