Features of Heavy Metals Distribution in Environmental Components of Urban Park Landscapes of Kyiv City

Abstract

We investigated the impact of the urban environment on the park ecosystems in Kyiv. As representatives of vegetation the species Taraxacum officinale Wigg. and Tilia cordata Mill., were chosen. The content of heavy metals (Cu, Pb, Zn, Ni, Mn, Cr, and Cd) in soil and leaf samples within the ecosystems of the parks Feofaniya, Kyiv Polytechnic Institute, Mariyinsky, Pushkin, and Nyvky was measured. The highest level of soil contamination with heavy metals was found in the areas of parks located near highways and public transport stops. The most polluted park was the Kyiv Polytechnic Park, and the least polluted Feofaniya Park. High levels of metals found in soil samples did not always coincide with their highest levels in the biomass of the studied plants leaves. We found that, according to the phytotoxicological classification of metals by the biological absorption coefficient (BAC) by plants within the studied park ecosystems, Cu, Pb, Zn, Ni, Mn, and Cr belong mainly to the elements of low absorption (hazard class IV) except for Mariyinsky Park, where Zn according to the BAC value belongs to the elements of moderate absorption (hazard class III). The order of amount of metal bioaccumulation in plants obtained by us show a fairly wide range for different park ecosystems, which confirms the principle of ecological congruence (compliance), according to which the living components of an ecosystem have developed appropriate adaptations coordinated by the abiotic environment. In order to identify additional ways of migration of heavy metals to the ecosystem of Feofaniya Park, hydrochemical data from the surface of the first aquifer, circulated within the study area, were involved. It has been suggested that the increased concentrations of Cu, Pb, Zn, Ni, and Mn in the soils of Feofaniya Park are connected with the Pirogivsky landfill, and the groundwater discharged into the park ponds serves as the main way of migration of pollutants to the natural environment, in particular to the soil-plant system. Our results confirm the need to involve biogeochemical data for ecological assessment of the urban environment and early diagnosis of negative influence, when the plants have not yet manifested morphological and anatomical abnormalities.