Mobility of heavy metals in the sediment of the To Lich River and the Kim Nguu River in Hanoi City

Abstract

The mobility of heavy metals in the sediment of the To-Lich River and the Kim-Nguu River in Hanoi City has been assessed based on selective sequential extraction procedure and the relationship between heavy metal concentration and organic matter content in the sediment has been examined. The heavy metal concentration of the sediment samples varied to a great extent by the difference of the sampling site and metal type. The heavy metals were bound with sediment particles through the phases such as exchangeable, carbonate, oxide, organic matter, and residual. The percentage of each phase was different according to the metal type; the organic matter and the oxide were predominant for the group of Cu, Pb, and Ni and the group of Zn and Cd, respectively, and each phase was almost equal for Cr. The total heavy metal concentration in the sediment was correlated with organic matter content for Cu, Pb, and Ni while no correlations were found for Cd, Zn, and Cr.