Concentration and partitioning of particulate trace metals in the Changjiang (Yangtze River)

Suspended sediments from the lower Changjiang (Yangtze River) were sampled to determine concentrations of Cu, Cd, Pb, Ni, and Cr. The particulate trace element values in the Changjiang are higher than in the Huanghe (Yellow River), but lower than in the other large Chinese rivers (e.g. Pearl River) and polluted rivers. A general pattern of high element levels in the clay minerals and low element concentrations in coarse sediment fractions are observed in the Changjiang. Sequential extraction shows the predominance of metals in the residual fraction relative to labile fractions in the Changjiang, emphasizing the importance of natural weathering and erosion in the drainage basin on the transport of particulate metals. Elevated Enrichment Factors (EF: the ratio of element concentration in microsurface to that in subsurface layer minus 1.0) suggest a potential influence of atmospheric input on the concentrations of particulate metals in the river.