Ecological risk assessment and sources of heavy metals in sediment from Daling River basin.

To investigate the distribution, source, and ecological risk of heavy metals in Daling River basin, 28 surface sediments collected in this region were analyzed by experimental and theoretical methods. Seven heavy metals, including Pb, Cr, Hg, Cu, As, Cd, and Zn, were detected in all samples. Monte Carlo simulation was used to assess the ecological risks of these heavy metals. It was found that the pollution of Cd was the most serious; the ecological risks in Daling River and Bohai Bay were significantly higher than those in estuary, Bohai Sea, and wetland, but overall, the ecological risks of these heavy metals were low to aquatic organisms in Daling River basin at present. Correlation analysis, principal component analysis, and cluster analysis showed that these heavy metals might originate from the same pollution sources located near Daling River and Bohai Bay.