The role of the mining and processing enterprise in the formation of techno-geochemical anomalies of arsenic in the soils of the Soymonovskaya Valley (Southern Urals)

Abstract

Introduction. The heterogeneity of soil cover of mountainous areas carries in itself the specific formation of technogeochemical anomalies in the areas of metallurgical combines, and the remoteness and inaccessibility of these areas requires detailed studies of the processes of pollutants in the soil and mechanisms of their behavior. The aim of the study was to investigate the influence of aero-industrial emissions from the copper smelter on the formation of techno-geochemical anomalies of arsenic in soils and its spatial distribution. Methods and materials of the research. Studies were conducted in the area of the Karabash copper smelter (KMC), located in the southern Urals (Russia), Chelyabinsk region, one of the main pollutants of soils is arsenic, which is formed in the Soymanovskaya Valley and adjacent landscapes techno-geochemical soil anomalies. In the course of works 25 soil sections were laid at different distances and directions from KMC, taking into account the specific geo-morphological features of the territory. In the selected soil samples we determined the acidity of the salt extract, the content of organic matter, granulometric composition, gross content of arsenic and its exchangeable form. Determination of arsenic was carried out by atomic adsorption spectrometry (AA-6800 Shimadzu). To identify the dependence of arsenic concentration in the upper 0-15 cm of the soil thickness with the distance from the CMC was carried out to calculate the Pearson coefficient and the concentration coefficient (Kc). Research results and discussion. The study area was divided into 5 zones depending on the distance from CMC. Excess concentrations of gross arsenic relative to the background content varies from 64 times in the 2 km zone to 3 times at a distance of more than 10 km. Maximum concentrations were recorded in the upper 0-15 cm of the soil thickness in the 2 km zone. The exchangeable form of arsenic has a specific accumulation near the combine, with a distance of more than 10 km from the combine, there is a tendency to reduce the content of this form, to a complete absence. In the intraprofile distribution there is a pattern of accumulation in the upper 0-15 cm of the soil layer, with depth significantly decreasing. Conclusions. Patterns in the spatial distribution of arsenic in soils based on the distance from the emission of aeroindustrial emissions were revealed. Maps of the spatial distribution of gross arsenic and exchange forms in the soils of the study area. It was determined that an important role in the formation of techno-geochemical anomalies plays pH of the environment. During the calculation of Ks revealed local areas that form anomalous halos dispersion, which are confined mainly to places near the CMC and the direction of the prevailing winds. Two local areas were identified for which the Kc values are more than 50. Pearson criterion calculations confirm the dependence of the spatial distribution of arsenic in soils on the wind rose. The results may be useful in the preparation of geochemical maps of arsenic distribution. In the prediction of local and radial differentiation of arsenic in other regions with similar activity of the combine, as well as in the correction of the regional geochemical background of arsenic in soils.