Soils from sites of historical metal mining in western Malopolska (S Poland) are strongly contaminated with Zn, Pb and Cd

Concentrations of Cd, Pb and Zn in soils developed at 63 sites of historical metal mining in western Malopolska (S Poland) were estimated. Heavy metal concentrations were measured with an atomic absorption spectrometer after wet digestion in hot HClO4 (total forms), extraction in 0.1 M BaCl2 (exchangeable forms) or in water (water-soluble forms). Basic soil properties such as texture, C, N, Ca contents and pH were also measured. Total concentrations of Cd in soil varied from 4.4 to 392, Pb from 72.8 to 16931 and Zn from 322 to 41860 mg kg(-1). Exchangeable Cd, Pb and Zn extended from 0 to 19.3%, from 0 to 0.2% and from 0 to 3.5% of the total metal forms, respectively, indicating that Cd is the most mobile and potentially bioavailable metal. In turn, water-soluble metal forms did not exceed 1% of the total. Our study showed that soils developed at sites of historical metal mining are severely polluted with heavy metals. Old heaps threaten not only the environment, but also local inhabitants, as they are often located in a close proximity to houses or agricultural fields.