Environmental quality of heavy metals in surface sediments in the central region of the Bohai Sea.

The distributions and environmental quality assessments of heavy metals Cu,Pb,Zn,Cr,V,Ni in the surface sediments in the central region of the Bohai Sea were performed.The contents of heavy metals Cu,Pb,Zn,Cr,V,Ni were 22.50,24.26,64.27,59.66,67.91 and 30.57?g/g,respectively.The contents were high in the Haihe River mouth and central region of the Bohai Bay,the mud area in the central study region and the coastal area of south Liaodong Peninsula;while that were low in the east of study area and the northern Bohai Bay.They were in middle level compared with that in other domestic and foreign regions.The heavy metals mainly came from natural sources,but were affected significantly by human activities.The environment quality evaluation of the sediment was carried out by the methods of geological cumulative index and ecological risk assessment.There were light polluted or non-pollution in the north Bohai Bay and the shallow of the central Bohai Sea at the east of study area;and light polluted along the coast of the south Liaodong Peninsula;while the western and southern areas of Bohai Bay,the central mud area of the Bohai Sea were medium polluted.The primary pollution element is Pb,which followed by Cr,Zn,V.The pollution of Cu and Ni were less.