Hydrochemical regime of rivers in the Borzhava River basin

The aim of the study was to analyse the hydrochemical parameters of surface water quality in the Borzhava River basin in Zakarpattia Region. Based on the collected data, a detailed analysis of the hydrochemical indicators of water quality in the Bozhava, Irshava, Salva and other rivers was carried out. This study was preceded by a detailed analysis of the natural conditions of the Borzhava catchment area and anthropogenic factors affecting the physical and chemical parameters, main ions and mineralisation of water, content of biogenic substances, heavy metals and specific pollutants. The ratio of calculated hydrochemical concentrations to maximum permissible concentrations for water used in fisheries was considered. The content of dissolved oxygen was found to be below the maximum permissible concentration, while the content of ammonium, phosphate, total iron, manganese, copper and zinc exceeded the normative values. The role of natural conditions in the formation of the chemical composition of surface waters in the Borzhava River basin was studied: the hydrological regime of waters, changes in water sources, the geological structure of the catchment area, and the main sources of anthropogenic impact along the river course were identified – unauthorised landfills, systematic discharges of domestic wastewater, insufficient treatment of municipal wastewater, agricultural development of floodplains and coastal lands, application of fertilisers during the farming season, and slowing of the flow in the canal system in the lower reaches of the Borzhava River, the Salva River, and the Balva Canal. It has been determined that the waters of the upper Borzhava River are hydrocarbonate calcium, moderately fresh with average mineralisation and clear seasonal variability. The results obtained are of significant practical importance and can be used in the preparation of the Tisza River Basin Management Plan, in the justification and implementation of environmental control measures for economic entities in the upper reaches of the Tisza, as well as in the development and implementation of environmental programmes aimed at improving water quality in the river basin