Distribution and speciation of metals in sediments along Le An River

Distribution of metal concentration and metal speciation in sediments along Le An River were studied．A high concentration of copper in sediments was found at Gukou，receiving Dexing Copper Mine effluents．It was decreased from Gukou to Daicun rapidly，but tended to increase from Daicun to Caijiawan Speciation of Cu，Cd，Zn and Pb were studied by sequential selective chemical extraction．The speciation fractions were classified into three bioavailable categories：easily bioavailable，moderately bioavailable and inert bioavailable The geoaccumulation index，Igeo，was used to illustrated the pollution level of heavy metals in sediments