The environmental danger of pollution of soils of urban territories of the mining region

Introduction. The article presents the results of the study of the quality of soil cover in the cities located in the mountainous areas of the Trans-Urals in the Republic of Bashkortostan. The object of the study was the soil of lands for various purposes in cities of Uchaly, Sibay, and Baymak. In the study of soils of industrial zones, there were taken samples adjacent to the dumps and tailing dumps of mining production at a distance of up to 500 m. In the recreational zone there were included the territories of parks, in the residential zone - all micro-districts where the population of the city resides. There were investigated territories of collective gardens located near sources of pollution.

Material and methods. The gross content of heavy metals and their mobile forms extracted from the soil of ammonium acetate buffer at pH 4.8 were determined by atomic absorption. Generally accepted ecological values of maximum permissible concentrations (MPC) and regional geochemical background (RGF) were used to estimate the degree of soil pollution. To assess the degree of soil pollution, the total ZC index was calculated using the formula proposed by Yu. E. Saet.

Results. As a result of the study, in all studied samples of the soil excess of MPC on gross forms on the content of Cu, Zn, in some cases, Mn, Cd, Co was revealed. Calculations of the General norm of Zc showed urban soil lands of all types of purpose by gross content to belong to the category of permissible pollution. The level of soil contamination with heavy metals in all the studied cities is higher in soils for industrial purposes. Increased level of mobile forms of Cu, Zn, Mn, Cd was revealed in all studied soil samples. The soils of the residential zone of Baymak according to the content of mobile forms belong to the moderately dangerous category of pollution, the rest of the studied soils had an acceptable category of pollution. In the cities of Sibay and Uchaly, the territories adjacent to the quarry dumps belong to a particularly dangerous category of pollution.

Conclusion. The level of soil contamination with heavy metals in urban areas of the Mountainous region of the Republic of Bashkortostan is determined by the type of destination of urban land. The most polluted are the soils of industrial zones located in close proximity to mining enterprises. The ecological danger of pollution is that in this zone there is a part of residential neighborhoods with knots, as well as garden cooperatives, where potatoes, vegetables and fruit and berry crops are grown.