FORMS OF CADMIUM, LEAD, AND ZINC IN CONTAMINATED SOILS FROM SOUTHWESTPOLAND

The metals Cd, Pb, and Zn occurring in Haplorthods and Haplumbrepts of both sandy and loamy textures in the vicinity of Tarnowskie Gory in s outhwest Poland, an area that has been subjected to severe metal conta mination, were studied according to a procedure based on sequential ex traction analysis. Concentrations of the metals ranged from background levels to levels well in excess of the maximum tolerable limits in ag ricultural soils. Thus, Cd, Pb, and Zn ranged from 0.2 to 103, 14 to 7 100 and 20 to 10000 mg kg(-1) soil, respectively. Soil type, texture, organic matter, and cation exchange capacity (CEC) did not influence t he relative proportions of heavy metal forms in any consistent manner. However, the influence of soil pH was clear. Soil samples of pH < 5.6 contained relatively more of all metals in the exchangeable form than in samples where pH was >5.6. The most consistent distribution patter ns were found when the soil samples were grouped according to their to tal metal contents. The inferred relative mobility of the metals and t heir redistribution among the different fractions are generally consis tent with the findings of previous studies of contaminated soils and s upport the view that metals from anthropogenic sources are more mobile than those from soil parent materials.