EN
The results of research conducted in the surroundings of a former polymetallic mine near the town of Zlaté Hory, North Moravia, Czech Republic, are presented. A by-product of the ore flotation technique was 6.8 million tons of metalliferous tailings. The adjacent forest area is contaminated by wind-blown pyritic dust particles. The experimental profile was located in a spruce monoculture down wind of the tailings. Samples of soil were taken at 50 m intervals. Ten soil pits were dug and soil samples were taken from the artificial top layer of deposited tailing dust, as well as from the Ah and Bw horizons. Soil samples were analyzed using AAS in order to obtain total heavy metal content of Cu, Zn, Pb, Cd and soluble forms of Al and Fe. The content of accessible nutrients (Mg, Ca, and K) was measured, as well as the content of organic carbon and the ratio of phosphorus retention. Both active and exchangeable soil pH was measured. Our results showed that the main problem is not heavy metal contamination per se, but rather severe acidification. The oxidation of pyrite has resulted in a decrease in pH (pH/H2O ranging from 3.1 to 4.1). The final values for Al and Fe solubility fall within either the aluminium or iron buffer ranges. Such severe acidification has led to increased toxic Al mobilization, the serious leaching of mineral nutrients (Mg: <0.05-34 mg·kg⁻¹, Ca: 0.6-244 mg·kg⁻¹, and K: <0.1-108 mg·kg⁻¹), and a high degree of irreversible retention of phosphorus (90-95%).