Ecological and Geochemical Assessment of the Regulatory Distribution of Microelements in the Bio-Inert Systems of the Natural and Technogenic Land Scapes of the Forest-Steppe Zone of Ukraine

Problem Statement and Purpose. The problem of environmental pollution with various potentially dangerous substances and, first of all, heavy metals, the impact of which will be carried out for many years, is the most important for environmental geochemistry. Despite the material accumulated in the literature, the forms of finding and mobility of trace elements in soils remain insufficiently researched; forms of migration of chemical elements in soil solutions, natural waters, entry into vegetation. The study of heavy metals in biomass systems of urban areas and their ecological assessment require systematic, comprehensive research. Establishing the relationship between the content of chemical elements in vital natural environments for humans is of particular importance. The main purpose of this article is to study the patterns of distribution of trace elements in the main types of soils, vegetation and forms of their migration in natural waters, background and technogenically polluted areas of the Forest- Steppe Zone. Data & Methods. The measurement of the content of heavy metals in soil and natural water samples was performed using the method of mass spectrometry with inductively coupled plasma (ICP-MS) on the Element‑2 analyzer (Germany). The forms of microelements in soil samples were determined by the method of successive extractions. The forms of migration of trace elements in natural waters were determined using mathematical modeling methods using specialized software tools GEMs v.3.2 and Hydra&Medusa. Results. The regularities of the distribution of microelements in soils, natural waters, and vegetation in conditionally clean and technogenic landscapes of the Forest-steppe zone of Ukraine were studied. The distribution of microelements in soils is determined by their physical and chemical properties, mineralogical and geochemical parameters of soil-forming rocks, landscape and technogenica conditions of the studied territories. Analytical studies were conducted to determine the mobile forms of microelements in soil solutions. Data were obtained on the regularities of the distribution of heavy metals in the soils of conditionally clean territories and the natural park of the NNP «Nizhnyosulsky», as well as their content in the vegetation of park landscapes. The gross content of Pb, Cu, Ti, Cr, V in the soils of the studied territory of the NPP «Nizhnyosulsky» is higher than the background values. The bio-inert systems of technogenic landscapes of the city of Brovary and Kyiv landfill № 5 were studied. It was established that the emissions of industrial enterprises of various profiles significantly change the geochemical background of metals in the analyzed soils of the city of Brovary. In these soils, the content of heavy metals, which are in the exchangeable and easily exchangeable fractions, increases and their mobility increases compared to the background ones. The highest level of soil contamination is observed on the territory of landfill № 5. Using the method of thermodynamic modeling, data on the forms of migration of microelements in soil solutions of technogenically polluted soils, natural waters (surface and underground) were obtained. Migration of heavy metals in soil solutions is carried out mainly in the form of free cations and dissolved organometallic complexes. The increased content of Mn, Cu, Co, Fe in the dry residue of the surface water of landfill № 5 was determined, which does not meet the sanitary standards for the discharge of wastewater into open waters. Pollution of surface waters by sewage with a high content of primarily organic toxicants: nitrates, vchlorides, was also found. The peculiarities of the microelement composition of drinking groundwater in the territory of Korostyshiv district of Zhytomyr region were studied. The dynamics of changes in the amount of total mineralization, the content of ions Ca2+, Mg2+, SO42–, Cl– in the aquifer of the fractured zone of crystalline rocks and their weathering crust were analyzed. A high positive correlation was found between the concentrations of Mg2+, SO42–, Cl– and their normalized indicators by the amount of water withdrawal. The obtained results testify to the significant role of the anthropogenic factor in the formation of the chemical composition of the studied groundwater. A comparison of the biologically significant concentrations (BSC) of the main microelements of groundwater with their content in water samples determined during the study allowed us to identify peculiarities: in the studied waters, an excess of such elements as Sr and Ba is observed. Instead, insufficient amounts of elements such as Li, V, Mn, Co, Ni, Cu, Zn, As, Cd and Pb were found. Based on the obtained results, conclusions were made about the presence of risks of some trace element diseases in the studied territory.