The comparison of extraction methods for evaluating some heavy metals in polluted soils

The extractability of Cd, Co, Cr, Ni and Pb was evaluated using ammonium chloride, calcium chloride, strontium chloride and DTPA extractants in this research. The eight surface soils were used to assess plant available metals with different extraction methods. The amounts of metal extracted were related to pseudototal contents, determined after microwave digestion using HNO3. Quantification of dissolved metals was used by ICP-MS matrix-matched standards. The obtained results indicated a high variability of metal extraction depending on extraction procedure, source of pollution, and nature of the soil. The results showed that the extractability for calcareous soils was best determined by DTPA. In comparison of chloride salts, a higher efficiency of extraction with ammonium chloride for these soils was found.