Keywords: correlation, heavy metals, lakes, sediment, metal speciation, Vietnam, water pollution
Metal speciation in sediment in West Lake (Ho Tay), Hanoi, Vietnam
The speciation patterns of Cd, Cr, Cu, Mn, Pb and Zn in 24 sediment samples from West Lake, Vietnam were investigated using a sequential extraction scheme modified from Tessier et al. The results indicated that only a very small portion of the total metal was easily available (found in the exchangeable (<5%) and carbonate (<15%) fractions for all metals except Mn). Stably bound metals account for the major amounts (25?47%) of Cr, Cu, Pb and Zn. The sequential extraction is useful to indirectly assess the potential mobility and bioavailability of the heavy metals in the sediment. The mobility of these metals is related to their solubility and geochemical forms, and it decreases in the order: Mn > Cd > Zn > Pb > Cr > Cu. Significant correlations among all extracted fractions for all six metals were observed. The number of correlations between any two metal binding fractions suggests that they might be discharged from the same pollution source.