Accumulations and risks of heavy metals in the sediments from 8 typical lakes in Wuhan, China

The content and species of 11 heavy metals in surface sediments from 8 typical lakes located in Wuhan,China,were investigated,and the accumulation,contamination,potential ecological risks and possible sources of metals were discussed in this paper.According to the metal geoaccumulation indexes,the results showed that the lake sediments had heavily polluted by Cd and evidently by Zn and Hg.On the whole,heavy pollutions of metals were observed in Lake Longyang and medium pollution in Lake Nantaizi and Lake Moshui,whereas the slight pollution in other lakes.Distribution of metals in sediments was observed to be not significant correlation with physicochcmical properties of sediments,whereas distinctly influenced by urban industries.11 metals distributed differently in lake sediments.The largest percentage of the form of available speciation was Cd in the lake sediments,with much higher potential ecological hazards,followed by Mn,Zn,Co,Cu and Pb.In contrary,As,Sb and Hg were dominantly associated with the residual fraction,indicating rare adverse biological effects.Correlation analysis and principal component analysis indicated that the heavy meal accumulation in the lake sediments were mainly attributed to the combustion of fossil fuel accompanied with metal refining,and followed with the effects of the biogeochemical processes of earth weathering.