Arsenic accumulation in spolic technosols in the area of a large copper smelting plant in the Middle Urals

Abstract

Relevance. The necessity to study arsenic behaviour in soils as one of the main pollutants of depositing environments in areas of mining and metallurgical industry. In recent decades, arsenic emissions into the environment have reached a huge scale, so this element attracts the attention of researchers around the world. But in spite of all the studies of this problem, there are still some aspects that need to be clarified to understand the geochemistry of arsenic. This paper deals with spolic technosols with critically high arsenic content in the soil profile with alternating water-logged and dry conditions. As one of the main soil-forming elements, orthosteins contain significant amounts of iron and manganese compounds and are capable of adsorption and involvement of the elements in nodule formation. Aim. To determine the influence of orthosteins on arsenic accumulation in soil subjected to intensive anthropogenic load. Object. Ortsteins spolic technosols in the zone of operation of copper smelting plant and background soils not exposed to pollution. Methods. Arsenic was determined by inversion voltammetry method. Morphological characterisation and patterning of the orthosteins were performed by scanning electron microscopy using a Thermo Fisher Phenom XL G2 Desktop SEM unit. Results. The study of morphological features of orthosteins revealed differences in soils subjected to greater anthropogenic load. Arsenic was not detected inside the orthosteins in all studied soils. Also arsenic concentrations in the total mass of ortstein is up to 40–50% of the soil mass. This fact indicates the accumulation of arsenic by surface adsorption and the appearance of orthosteins as a geochemical barrier. The data obtained in the course of this work can contribute to the search for ways to clean up soils contaminated with arsenic, as well as provide an understanding of the basic processes of the behaviour of this element in soil formation.