Ecological and Geochemical State of Soil Cover in Gusinoozersk in the Zone of Influence of Coal Thermal Power Plant

Abstract

The pollution of the topsoils of the city of Gusinoozersk (Republic of Buryatia) under the influence of emissions from State District Power Plant (SDPP) which used the Okino-Klyuchevskiy brown coal as fuel was studied. The content of 14 elements (Sr, As, Co, Mo, Sb, V, Cu, Ni, Cr, W, Zn, Bi, Cd, Pb) in bulk samples, as well as in the fraction of physical clay (particles with a diameter 10 µm, PM10) and in samples of brown coal and ash from the SDPP. Strontium, As, Co, Mo, Sb, V are the priority pollutants in the soils of Gusinoozersk with higher concentrations of most elements in the PM10 fraction. Soils and the PM10 fraction in the industrial operating subzone are the most polluted with Sr, As, Co, V, Cu, Mo, Ni, Cr, which are contained in the fly ash of the Gusinoozerskaya SDPP. Most of the territory (57% for soils in general and 47% for the PM10 fraction) is characterized by a low level of pollution (Zc = 8–16). Arsenic poses the greatest environmental hazard; in the PM10 fraction, its concentrations exceeded the MPC in 90% of the studied samples. In soils and their PM10 fraction, the leading factors for the accumulation of elements are the content of Fe2O3, organic matter, soil texture, alkaline-acid conditions, and belonging to a functional zone, which determine the formation of various classes of geochemical barriers. The polluting effect of brown coals depends on the content of heavy metals and metalloids in them. Comparison of the chemical composition of the Okino-Klyuchevskii brown coal and ash from the Gusinoozerskaya SDPP and the Kansk-Achinskii coal and ash from the Central Thermal Power Plant of Severobaikalsk showed that the brown coal and ash from Severobaikalsk were slightly enriched in metals and metalloids, which significantly reduced their accumulation in soils.