Features of heavy metals and metalloids accumulation in soils of Samara and Syzran large recreational zones

The paper discusses the results of ecological and geochemical studies of soils in the Sokolii Mountains located near Samara and in a specially protected natural area Monastyrskaya Mountain located within the borders of Syzran, Samara Region. These territories are of great interest in connection with their active use for urban recreation. The studied parts of the Sokolii Mountains (northeastern, eastern and southeastern surroundings of the Kuznetsov Mountain) are natural forests, the protected area Monastyrskaya Mountain is an artificially created forest stand. The territories under comparison differ in their origin, typological characteristics of soils, including their granulometric composition and humus content, as well as in the degree of recreational pressure. It has been established that heavy metals and metalloids accumulate more actively (2,0–5,5 times) in the soils of the upper layer in the vicinity of the Kuznetsov Mountain than in the sandy and loamy soils of the Monastyrskaya Mountain, which are characterized by a more significant geochemical heterogeneity. In both territories, the average concentrations of chemical elements do not exceed regional clarks and maximum permissible concentrations. An analysis of the geochemical indices of the studied soils revealed the predominance of the scattering of heavy metals and metalloids over the concentration processes in them. According to the magnitude of concentration clarks and scattering for both recreational territories, an association of accumulating elements was revealed; it included only Se and Cd while the association of scattering elements included Sr, Rb, Cr, V, As, Pb, Ni, Co, Cu, Zn, Mn. In the soils of the Monastyrskaya Mountain dispersal processes are more presented while in the soils of the Kuznetsov Mountain surroundings accumulation processes are more presented. In general, the northeastern, eastern and southeastern environments of the Kuznetsov Mountain and the Monastyrskaya Mountain are characterized by a relatively low level of heavy metals and metalloids pollution, which makes it possible to consider these territories as environmentally sustainable, but requiring the development of a scientifically-based mode of recreational use.