Mobility of Cd, Pb, Cu, and Cr in some Estonian soil types

The sorption capacity of selected heavy metals (Cd, Pb, Cu, Cr) to five Estonian soils was evaluated using spiked subsoil samples in laboratory experiments. The experimental sorption data fitted well to the linear Freundlich isotherm. The sorption of metals in subsoil depended on the soil type, e.g., mineral composition. The results indicate that the content of quartz and carbonates is important in affecting the metal sorption capacity of subsoil. On the basis of our data the possibility of penetration in depth and accumulation of mobile metals was evaluated. It was concluded that increase in dissolved Cd and accumulation of other metals in the subsoil of Podzol is expected. The accumulation of Pb could be the main process for soils with a high amount of dolomite.