Heavy metals distribution in soil particle size fractions from a mining area in the southeast of Spain

The distribution of heavy metals in soil particle size fractions from soils on two representative tailing ponds, El Lirio and El Gorguel, from the southeast of Spain has been studied. In both tailing ponds heavy metal mobility is not enhanced owing to the high pH despite a low buffer capacity. In addition, the materials showed a low fertility and high salinity, which prevent plant colonization and leave their surface unprotected against wind and water erosion. The dominant fraction for both ponds was 425n150 mm, while the finest fraction represented 23 % and 20 % for Gorguel and Lirio tailing ponds, respectively. High concentration of metals occurred in both finest and coarsest fractions due to high surface area and negative charges associated with fine particles and the processes of treatment of the ore. The results showed high pollution of these ponds for all the fractions. However, highest enrichment factors (EFs) were in the finest (l75 mm) and coarsest (2000-425 mm) particles with EFs g10 for Pb; g15 for Cd and g20 for Zn in Lirio and EFsg10 for Pb; g20 for Cd and g30 for Zn in Gorguel.