LAUSR

Heavy metal concentrations in surface sediments of the Dragon Lake were studied based on the field investigation, sampling, indoor test and statistical analysis. Pollution risk was assessed using geoaccumulation index (Igeo), potential ecological risk index (PERI) and sediment quality guidelines (SQGs). The enrichment level of heavy metals in surface sediments decreased in the order of Cd>Zn>Cu>Ni>Pb>Mn. Igeo and PERI indicated Cd had the highest biological risk among the six heavy metals. The concentrations of Cd, Ni and Zn were between threshold effect level (TEL) and probable effect level (PEL), suggesting adverse biological effect occasionally occurred. Comparing the north and south of Dragon lake, the north part should be given more attention due to the higher heavy metal concentrations. The metals (Cd, Zn, Cu, Ni, and Pb) were attributed to anthropogenic sources, including agriculture, industrial emissions and traffic pollution, whereas Mn was mainly from natural sources. The results can provide reference for water quality management of Dragon Lake.