The role of vegetation cover in the cycle of chemical elements in the zone of impact of a non-ferrous metallurgy enterprise (Southern Urals)
V.V. SOMOV, M.G. OPEKUNOVA, A.YU. OPEKUNOV, S.Yu. KUKUSHKIN, D.V. KORSHUNOVA, E.V. DERGILEVA, I.Z. MIRZOYAN, D.A. AKULOV
Saint Petersburg State University, St. Petersburg, Russia
Keywords: soils, plants, geochemical barriers, biogeochemistry, steppes, mining production
Abstract
The article is concerned with the study of the influence of the herbaceous vegetation cover of terrestrial and aquatic facies on the cycle of ore and associated chemical elements near the site of Cu-Zn pyrite deposit development and Cu concentrate production (Southern Urals, north of the steppe zone, Republic of Bashkortostan). Thirty-five test plots were studied, 106 samples of total cuttings, 118 soil samples, 38 reed samples, and 38 bottom sediment samples were processed. Correlation and regression analysis of the Cu, Zn, Fe, Mn, Ni, Pb, Cd, Co, Cr, Ca, Sr, Ba, V, Sc, and Sb content in total cuttings, reed samples, soil and bottom sediments was carried out. The content of individual forms of chemical elements in the soil was determined by the sequential extraction method. The reserves of elements in total cuttings, the humus soil horizon (total reserve and the reserve of three mobile fractions), and reed beds were calculated. The volume of Cu, Zn, and Cd input with dump drainage waters was estimated. The role of reed beds as a geochemical barrier in a polluted small river was revealed. Arguments were obtained in favor of a weak stabilizing effect of grass stand on the Cu and Zn reserve in the soil; the Cu and Zn contents in cuttings are interrelated, despite the variability of the abundance of different plant species; they also do not correlate with the contents of these elements (both total and mobile forms) in the soil. A hypothesis is substantiated that excessive grazing (or other mechanical impact) near mining facilities can lead to an increase in the abundance of metal-concentrating species, due to which both the concentration and the Cd reserve in cuttings significantly increase. It was found that in the studied river reed beds can act as a biogenic geochemical barrier for Cu (but not for Zn or Cd). Suggestions for increasing the barrier efficiency are presented.
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