Distributions and ecological risk assessment of heavy metals in Shuangdao Bay of Weihai

Based on the data of environmental survey of Shuangdao Bay in 2012,the distribution patterns and ecological risk assessment of heavy metals in seawater and surface sediments were analyzed.The results show that the contents of Cu and Pb in seawater are higher in the middle and end of the bay,Zn and Cr are the highest in the end of the bay and the lowest in the external bay,Cd and Hg are the lowest in the middle of the bay,while the distribution of As is uniform.Compared with other estuaries in adjacent area,all heavy metals except Zn and Pb show a higher level.The contents of heavy metals in surface sediments are low,the distributions of Hg and Cd in the mid bay and Cu,Pb and Cr in the external bay are higher than those in other areas.The correlation analysis show that no significant relationship is found between organic carbon and heavy metals in surface sediments.The ecological risk assessment indicates that the pollution of heavy metals in seawater is in the lowest level,the surface sediments has low to medium potential for biological toxicity effect,the sequence of ecological risk intensity caused by different heavy metals is PbAsCuHgCr=CdZn.