Pollution and Potential Ecological Risk of Heavy Metals in Core Sediments from Majuan Lake in Lianhuan Lake, China

Sedimentation rates, element concentrations and grain size distributions of core sediments from Majuan Lake are investigated. According to210Pb and137Cs dating, the pollution history of Majuan Lake is investigated based on the geochemical characteristics in core sediments. Our findings indicated that Cr, Cu, Mn, Ni, Pb, Zn and Cd are the main pollution heavy metals, which have different pollution history and pollution degree. The concentrations of heavy metals in sediments varied smoothly before1987. However, the concentrations of all elements increased obviously since 1987, which are mainly attributed the industries development. In recent years, Cu, Ni, Cr, Pb, and Zn in most sediment from upper profile showed moderate ecological risk level, but Mn and Cd showed strong ecological risk in the sediments. Similar results obtained from Eir and RI methods, while the heavy metal content increased rapidly since 1987 with the peak values appeared in the surface, which indicated the strongly potential risk. The history of elements pollution has strong link with the economy development in the catchment of Majuan Lake.