Urban rivers are often utilized by the local residents as water source, but they can be polluted by heavy metals
due to industrialization. Here, the concentrations, toxicity, speciation and vertical profiles of heavy metals in
sediment were examined to evaluate their impact, dispersal and temporal variation in Dongbao River. Results
showed that the sediment in the industrialized areas was seriously contaminated with Cr, Cu and Ni which
posed acute toxicity. Heavy metals, except Cr and Pb, were mainly associated with non-residual fractions, indicating
their high mobility and bioavailability. The non-industrialized areas were also seriously contaminated, suggesting
the dispersal of heavy metals along the river. The surface sediment could be more contaminated than the deep
sediment, indicating the recent pollution events. Overall, when the point sources are not properly regulated,
intense industrialization can cause both serious contamination and dispersal of heavy metals, which have farreaching
consequences in public health and environment.