Abstract The content and phase-specific bonding forms of selected metals (Zn, Ni, Cd, Cu, Pb, Cr) in the sediments of the Vistula River and its tributaries were studied. The concentrations of heavy metals mainly in the upper Vistula River are very high. According to metal speciations, they can be subdivided into two groups: (1) highly mobile elements—Zn, Cd, Cu; and (2) metals more strongly combined with the solids—Cr, Pb, Ni. The buffer capacity and the mobility of metals of the two contaminated sediments were determined. The “titration curves” show that the presence of calcite is the most important factor affecting the buffer capacity.