Influence of the exploitation of Sibay deposit (the Southern Urals) on the transformation of metal migration in subordinate landscapes
The regularities of migration and accumulation of heavy metals in geochemical conjugations under mining technogenic conditions were studied. The case study examines mining and milling of copper-zinc ore deposits in Sibay (the South Urals region). Landscapes in the valley of the Karagaily River, the Southern Urals, have been the objects of investigation since 2004. Soils and vegetation of the watershed, river water, bottom sediments and mine wastewater entering the watercourse were investigated, and the role of technogenic and artificial geochemical barriers was estimated. It is found that mining industry causes significant contamination of natural environment with Cu, Zn, Cd, Fe and Pb. Water bodies occupying the lowest level in geochemical interactions experience the maximum load. On the average the concentrations of Cu, Zn and Cd in dispersion flow (water, bottom sediments) are by two orders of magnitude higher than their percentage abundances. Migration and accumulation of metals are governed by technogenic physical and chemical barriers, among which the alkaline and sorption ones play the leading role. Heavy metal concentrations in biomass, coastal aquatic and terrestrial vegetation were found. Low values of the coefficient of biological absorption by plants compared to the background were revealed. We concluded that plants act as a certain phyto-barrier stabilizing the technogenic flow of substances and reducing the intensity of pollutants consumption by top organisms of the food chain. The violation of interdependence of substance flows in subordinate landscapes and the lack of correlation between concentrations of metals in soil-forming rocks, soil, plants, water and bottom sediments are also shown.