COMPARATIVE ANALYSIS OF APPROACHES TO ECOLOGICAL ASSESSMENT OF POLYELEMENT CONTAMINATION SOIL OF URBAN ECOSYSTEM BY HEAVY METALS

In modern conditions, anthropogenic impact to the soil urban ecosystems is fairly stable over time and space, is manifested in various forms, as the transformation of the soil profile, the change in direction of the soil-forming processes, contamination of the various pollutants, and, above all, heavy metals (HM) ? elements of the first class of the danger. Their sources of the income to the urban environment are industrial enterprises, transport, housing and communal services. Determination of the anthropogenic pressure to the urban soil is carried out by the environmental assessment of the HM polyelement contamination, which allows to establish not only the fact of pollution, but also limits of the possible load with considering regional background or sanitary standards ? MPC. However, until now discussions arise regarding the index which will be carried out the valuation ? the cornerstone of any methodological approach to the environmental assessment of the soil polyelement contamination by the HM of the urban ecosystems, which allows to establish not only the fact of contamination, but also limits the possible load, taking into account the regional background or sanitary norm ? MPC. Purpose. Lies in the grounded selection of the environmental assessment indexes of the soil contamination by the HM of the urban ecosystems through a comparative analysis of the existing approaches, such as the determination of the summary contamination index (SCI), the index of the soil contamination (ISC), factor imbalance (Sd), taking into account environmental safety standards and binding to the specific conditions territory. Conclusion. In summary it should be noted that it is necessary to use a set of integrated indexes, including the SCI to determine the violation of the metals content with respect to the geochemical background of zonal soil, ISC ? link the contamination level with health indexes of the environmental safety territory, and Sd ? consider a soil destruction, which is caused the construction process. Statistical analysis indicates their high affinity, which is reflected by the correlation coefficients. According to the assessment of these indexes the soil of Dnipropetrovsk urban ecosystem is increasingly polluted by Pb and Zn than Ni, the contamination level is mainly low to moderate, and soil is mostly problematic and polluted by ISC, although there are some hot spots in industrial zones of the city.