Arsenic in soils in the areas of former mining and mineral processing in Lower Silesia, southwestern Poland

Abstract

In recent years, great concern has been focussed on worldwide contamination of soils by As and its risks to humans and the surroundings. In Poland, soil-arsenic problem is mainly confined to industrial, mining, and smelting areas. In this study, we have indicated a few “hot spots,” where soils contain extremely high concentrations of As, caused both by natural enrichment and long-lasting ore mining and processing activities. In this chapter, the total concentrations and speciation of As in soils in the areas of Zloty Stok, Zelezniak, and Czarnow where As ores were mined and processed for over centuries are presented. It was observed that soil pollution occurs mainly in the close vicinities of mine and slag spoils as well as in alluvial soils. Maximum concentrations of As in mine spoils in Zloty Stok, Czarnow, and Zelezniak sites were reported at 8800, 40 600, and 18 100 mg/kg, respectively, and its concentrations in tailings in Zloty Stok was at 8500–17 200 mg/kg. Alluvial soils in the above-mentioned regions contained up to 11 500, 4210, and 6800 mg/kg of As, respectively, and the soil pollution load decreased downstream. Other soils (mainly Cambisols) surrounding mining areas are also contaminated by As. Twenty-six soil samples and waste materials were examined by sequential extraction and five operationally defined As fractions were determined by: (1) non-specifically sorbed; (2) specifically sorbed; (3) associated with amorphous; (4) crystalline Fe oxides; and (5) residual. Arsenic was present in soils mainly in association with amorphous Iron (Fe) oxides.