Spatial distribution, ecological risk assessment and source identification for heavy metals in surface sediments from Dongping Lake, Shandong, East China

Surface sediment samples collected from 18 sites in Dongping Lake were analyzed for selected heavy metals including As, Cd, Cr, Cu, Hg, Pb, and Zn to determine their spatial distribution, source, and potential ecological risks. The enrichment degree of the studied metals decreased in the order of Cd > Hg > As > Pb > Cu > Cr > Zn, and the average concentrations of Cd, Hg and As were 3.70, 3.69 and 3.37 times their background values. With the exception of Cd, the concentrations of heavy metals decreased progressively from the southeast to the north and west within the lake. Based on the enrichment factor (EF) and the potential ecological risk index (PERI), As, Cd and Hg were the heavy metal contaminants of most concern in surface sediments. Moreover, referencing to the results of multivariate statistical analyses, we deduced that anthropogenic As and Hg were mainly from industrial and mining sources within the Dawen River watershed, whereas, Cd originated from agricultural sources.