Distribution characteristics and pollution evaluation of heavy metals in surface sediments in the Northwest of Liaodong Bay

Seven heavy metals (Cu, Pb, Zn, Cd, Cr, Hg and As) in surface sediments from 26 sites in the northwest waters of Liaodong Bay in autumn of 2013 and spring of 2014 were investigated.The results showed that the concentrations of Hg, Zn and Cd were higher than the background values of Bohai.Marine sediment quality was evaluated with the single factor pollution index method.The results showed that the average value of Hg, Cu, Pb, Zn, Cd, Cr and As conformed to the first-class standard of marine sediment quality.The geo-accumulation index of Hg, Cu, Pb, Zn and Cr were in zero level, and Cd were low.The potential ecological risk of Cd was in middle level and Hg, Cu, Pb, Zn, Cr and As were low.The potential ecological risk of heavy metals was relatively low.Positive correlation was observed between concentrations of 5 heavy metals (Hg, Cu, Cd, Cr and As) and TOC, respectively.Result of principal component analysis showed that the three main sources of heavy metals in marine sediments were industrial wastewater, urban sewage and aquaculture pollution itself, degradation of organic matter and erosion of rocks.This article revealed the distribution of the heavy metals in the northwest of Liaodong bay in order to provide scientific basis for marine sustainable development and marine ecological civilization construction.