Mobility and Bioavailability of Heavy Metals in Sediments Using the Sequential Extraction in Yeongsan River Basin,...

The chemical fractions of heavy metals in sediments provides important information on their mobility, bioavailability, and toxicity. This study identified the chemical fractions of six heavy metals (Pb, Zn, Cu, Cd, Cr, and Ni) in the sediments of Yeongsan River Basin, South Korea. The heavy metals were bound to sediments in the order of Pb ≈ Cd > Zn > Cu > Ni > Cr in the labile fraction, and Pb, Cd, Zn, and Cu exhibited high mobility and bioavailability. The risk assessment code (RAC), individual contamination factor (ICF), and global contamination factor (GCF) assessment results confirmed that the mobility and bioavailability of the heavy metals were relatively higher in the mid-upstream compared to downstream. The sediments in the mid-upstream had a high proportion of heavy metals bound in the labile fraction, indicating a close relationship with pollutants discharged from densely populated regions and industrial complexes.