Forms of metal(loid)s in soils derived from historical calamine mining waste and tailings of the Olkusz Zn-Pb ore district, southern Poland: A combined pedological, geochemical and mineralogical approach

Historical calamine mining in Poland has resulted in the deposition of trace element contaminated waste on the land surface. Further, the elements occurring in calamines may become bioavailable in calamine soils, depending on their properties and the mineral composition related to past mining processing. The goal of this study was to determine the forms of selected elements (Zn, Pb, Cd, and As) in technogenic soils developed from diverse calamines (calamine mining wastes and tailings) in the Olkusz region of southern Poland in relation to soil properties and mineralogy. The following soil properties were measured: pH, the content of carbonates and soil organic matter. Mineral and chemical composition was determined using XRD, SEM-EDS, and EPMA. Further, the total concentrations of Zn, Pb, Cd, and As were determined, and the chemical forms of soil elements were identified using a BCR sequential extraction procedure. The soils developed from calamine mining waste had higher pH (7.3-8.3) and higher carbonate content (<67%) compared to soils from calamine tailings (4.8-7.8 and < 19%, respectively). All soils contained high total contents of Zn, Pb, Cd, and As. In the past, different calamine processing techniques influenced the properties, mineralogy, and chemical forms of toxic trace elements (Zn, Pb, Cd, As) in the parent material of soils developing on the surface of calamine disposal sites. It was found that higher percentages of Zn, Pb, and Cd occurred in more mobile forms in acidic soils developed from calamine tailings compared to soils from calamine mining waste, which was caused by the lower pH values and lower carbonate content of the former soils.