Assessment of the protective potential of the Moscow region soil cover to contamination with heavy metals and metalloids

Abstract

Heavy metals and other trace elements that are not subject to degradation are among the priority pollutants. Significant amounts of heavy metals and related elements with variable valence are deposited on the soil surface as part of aerosols. Accumulating in the soil, they are very slowly removed from it, only changing the level of content or the state during migration, turning the soil over time into a source of secondary pollution. In this regard, an extremely urgent task is to assess the territory, especially such a highly developed and densely populated area as the Moscow Region, in terms of its protective potential to heavy metal pollution. The paper proposes and tested an algorithm for the cartographic assessment of the protective potential of the soil and vegetation cover of the region using GIS analysis methods based on the database “Digital medium-scale soil map of the Moscow region” and a vector map of forest cover. The formula used for calculations includes data on the soil texture, the content of organic matter in soil, the position of the soil in the landscape and the degree of forest cover of the territory. According to the proposed approach, in the Moscow region, the soil cover, taking into account the forest cover, forms 4 groups according to the level of protective potential for contamination with heavy metals and metalloids. The maximum estimate was obtained for noneroded sod-podzolic soils of medium or fine texture, gray forest soils, chernozems and peat bog soils under forest vegetation (17 % of the area). Unerroded soddy-podzolic soils of varying degrees of podzolization and gleying (45 %) received an average rating. Even lower is the protective potential of 22 % of the territory represented by eroded gray forest soils, various sod-podzolic, alluvial and peat bog soils. This group is the most heterogeneous in terms of soil texture, organic matter content and degree of forest cover. The group with a minimum protective potential included eroded soils, soils of gully-girder complexes, sod-podzolic soils of coarst texture, as well as alluvial peat and peaty soils (about 16 %).