Adsorption of heavy metals Cu,Pb,Zn over top sediment in North River Canal
北运河表层沉积物对重金属Cu、Pb、Zn的吸附

The concentration of heavy metals (Cu,Pb,Zn) and the characteristics of top sediment from six sampling sites distributed in North River Canal were analyzed.The distribution coefficient Kd was used to evaluate the adsorption capacity of Cu,Pb and Zn over the top sediment.The effect of solution pH and dissolved organic matter on the removal efficiency was also studied.The results indicated that the adsorption capacity of sediments significantly decreased when the dissolved organic matter was removed from the sediments.However,there was almost no significant correlation among the amount of heavy metals in sediments,the adsorption capacity of sediments and the concentration of dissolved organic matter.This may be attributed to the different species and structures of DOC in the six sampling sites.All the sediments showed the highest selectivity towards Pb with a selectivity order of Pb>Cu>Zn and the adsorption capacity increased with the increase of solution pH.The solution pH had the maximum effect on the adsorption of Zn among the three hevay metals (Cu,Pb,Zn).