Assessment of potential risks associated with heavy metal contamination in sediment in Aobaopao Lake, China, determined from sediment cores.

Lianhuan Lake is found in the lowest point of the Songnen Plain in Eastern China and is a typical hardwater lake. Lianhuan Lake is constituted by eighteen lakes and Aobaopao Lake is located in the eastern portion. Geochemical features and pollution history of heavy metals in Aobaopao Lake were investigated. Total metal contents and chemical fractionations of Cu, Fe, Mn, Ni, Pb, Cd, Cr and Zn were analyzed for core sediment samples taken from north sampling site for Core AB1 and south sampling site for Core AB2 of the lake using the speciation extraction procedure proposed by the Commission of the European Communities Bureau of Reference (BCR) together with grain size and TOC measurements. Heavy metal analyses showed that sediments have similar geochemical features. In order to quantify the anthropogenic contamination of the metals according to their speciation composition, the RSP approach was applied. In Core AB1, Cd is moderate and significant contaminate while Mn is minor, moderate and significant contamination. In Core AB2, Cd is more significant contaminate from 3.75 cm to the surface. The risk assessment code (RAC) established by Perin et al. (Heavy Metals in the Environment, CEP Consultants, Edinburgh, 1985) was used to evaluate the risk of heavy metals in sediments of Aobaopao Lake. The results for both cores suggest that Mn and Cd posed a high risk to local environment.