Distributions and risk evalutionof heavy metals in Dalian coastal areas

The inductively coupled plasma mass spectrometry(ICP-MS)was employed in the chemical composition analysis for the surface seawater,surface sediments and shellfishes collected from Dalian coastal areas.Based on the results,the chemical features including heavy metal contents,distribution and enrichment coefficient,and comprehensive evaluation for pollution are discussed.The mean contents of chemical elements (Zn,Cu,Cr,Cd,Pb,Hg)were 15.2,1.21,0.59,0.13,0.104,0.038 g/L in surface seawater,51.810-6、11.210-6、20.410-6、0.0710-6、13.510-6、0.02110-6in sediments,and 10810-6、0.3610-6、1.2510-6、0.1110-6、0.01610-6 in shellfishes (except Cu).The enrichment capacity of heavy metals in sediments was higher than that in organisms.The heavy metal Pb had the highest enrichment in sediments while Cd and Zn could be most strongly absorbed by scallops and oysters,respectively.The result shows that the surface sediments suffered from relatively low heavy metal pollution,whereas Hg had certain potential ecological risk.