Radial geochemical barriers in soils of the Perm territory

Abstract

Geochemical barriers in soils control the composition and intensity of geochemical fluxes of natural and technogenic substances in landscapes. The Perm Territory is an industrial region. The total volume of emissions from enterprises of the chemical industry, oil and gas industry, transport, mechanical engineering, metallurgy, electric power industry in 2020 exceeded 380 thousand tons. A sharp spatial change in relief elements, a wide range of temperature parameters of the climate and moisture conditions create a diverse combination of soil-forming factors and, as a result, the diversity of the soil cover of the region, determine the manifold of geochemical settings and differences in the buffer capacity of soils. The objectives of the study included mapping radial geochemical barriers to assess their spatial heterogeneity in terms of anchoring mechanisms and barrier capacity. The soil map of the Russian Federation at a scale of 1:2500000 served as the thematic basis. The database of soil properties was compiled on the basis of the data of the Unified State Register of Soil Resources of Russia with the involvement of regional sources. All maps and attribute databases for them were created using QGIS version 3.2.2 (Maderia). The mapping technique is based on the “horizon approach,” according to which genetic soil horizons are considered as radial geochemical barriers. Two maps of radial barriers were created: surface biogeochemical barriers and physicochemical barriers of the middle horizons. The estimate of the capacity of the surface organic and organomineral barriers of soils in the region was carried out according to the following indicators: the thickness of organogenic and organomineral horizons, humus content, and granulometric composition. The capacity of surface biogeochemical barriers follows a geographical pattern: from north to south of the region, the capacity of organic barriers decreases and the capacity of organo-mineral barriers increases. Among the intrasoil physical and chemical barriers of the soils of the region, the following were distinguished: carbonate, gley and sorption. In general, the region is dominated by oxidizing conditions with a high-capacity sorption-sedimentation barrier in soils. Podzolic and soddy-podzolic soils, occupying 62 % of the region’s area, have a sorption-sedimentation barrier. Podzols, podburs, brown-taiga soils have a low- and moderately capacious chemisorption barrier. The soils of the forest-steppe are characterized by a moderate sorption-sedimentary barrier. Gley barriers of hydromorphic soils occupy approximately 20 % of the area. These maps can be recommended for inclusion in the “Soils” section of the regional comprehensive geographic atlas.