CHEMICAL AND MINERALOGICAL FORMS AND MOBILIZATION OF COPPER AND LEAD IN SOILS FROM A CU-SMELTING AREA IN POLAND

Sequential chemical extraction, scanning electron microscopy/energy dispersive microanalysis (SEM/EDX) and x-ray diffraction (XRD) were used to determine the chemical and mineralogical forms of copper and lead in a soil sample containing 7400 and 1960 mg/kg of these metals respectively, taken from the vicinity of a copper smelter at Legnica in southern Poland. Sequential extraction suggests that a high proportion of copper and lead (about 70 and 60% respectively) could be mobilized from the exchangeable and carbonatic fractions of the soil. SEM/EDX analysis of soil particle size fractions indicates however, that the Cu and Pb are mainly associated with sulphides and/or sulphates but to a minor extent with carbonates and on exchange sites. The SEM micrographs suggest that the heavy metals occur in three major forms, namely single grains, aggregates, and thin patches on or in silicate and carbonate minerals.