ECOLOGICAL AND GEOCHEMICAL SPECIFICS OF SOIL AND PLANT COVERING OF URBAN LANDSCAPES (IN THE TOWN OF BROVARY AS AN EXAMPLE)

Abstract

The results of the pollutants content research in urbanized landscapes soils of Ukraine (on the example of Brovary city, Kyiv region) were shown. The total and mobile contents data of chemical elements (Ni, Co, Zn, V, Pb, Cr, Cu) were obtained and analyzed using the methods of landscape-geochemical studies, analytical and statistical methods. The dependences of the vegetation resistance in cities to the level of soil cover contamination and the degree of heavy metals income have been established. The geochemical characteristics (such as the value of the accumulation coefficients; concentration of soil and vegetation cover; index of biogeochemical activity of the species within Brovary city) were analyzed.
 Throughout most of the city territory, the level of soil contamination is above average. Soils are characterized by the following association of heavy metals: Cu> Pb> Zn> Co> Cr> V> Mo> Mn> Ni. The dominant association is distributed heterogeneous throughout the city, forming geochemical anomalies depending on the source of contamination. The maximum technogenic load was recorded in urban soils areas within zones of transport infrastructure, production and communal-warehouse facilities.Woody vegetation is the most actively absorbed copper, manganese from the soil, and the least intensively absorbed chromium, vanadium and nickel. The biogeochemical activity coefficient of the research species is the following: Acer platanoides - 7,26, Betula pendula Roth. - 7,07, and Populus deltoides - 7,05, Pínus sylvestris - 1.32 and Alnus incana - 3.37. The biological absorption coefficients of manganese and copper are high because these metals have the ability to form strong complexes with organic matter. Biological absorption coefficients of vanadium and chromium is low for the researched plant species because these chemical elements are immobile in soils.
 For the city of Brovary, the presence of polyelemental contamination of soil and vegetation has been established. According to the indicators of the gross content of VM, the main pollutants are Cu, Zn, Pb and Mn. Concentrations of gross and mobile forms of VM exceed background values ​​and maximum concentration limits in 17-28 times. The maximum of man-caused load was recorded in the urban soils of the transport infrastructure zone and the zone of production and communal-warehouse facilities.
 Regularities of formation of elemental composition of plants of urban areas undergo significant changes in comparison with natural conditions, which is due to the strengthening of the role of foliar absorption of pollutants from the air and their high content in soils. The greatest ability to bioaccumulate has a male thyroid (Dryopteris filix-mas Schott) and birch (Convolvulus arvensis). The highest coefficient of biogeochemical activity of the studied species is Acer platanoides - 7.26, hanging birch (Betula pendula Roth.) - 7.07 and Canadian poplar (Populus deltoides) - 7.05, the lowest - Scots pine (Pínus sylvеstris ) - 1.32 and gray alder (Alnus incana) - 3.37. Weakly and very weakly, most of the studied plant species capture vanadium and chromium, which are relatively sedentary in the soil.
 Further research is needed to analyze the physicochemical parameters of soils, the coefficients of transition of metals to plants relative to their content in organic and mobile form in order to establish the relationships that characterize the process of translocation of chemical elements.
 Keywords: landscape-geochemical conditions, heavy metals, soils, vegetation.