SPATIAL AND TEMPORAL FEATURES OF WATER CHEMISTRY CHANGES IN THE QUATERNARY UNCONFINED AQUIFERS OF THE DNIPRО RIVER BASIN

• Дата: 2023
• Автори: Люта, Н.Г., Саніна, І.В.
• Формат: Стаття
• Мова: English
• Опубліковано: Institute of Geological Sciences, NAS of Ukraine 2023
• Теми: groundwater; unconfined aquifers; conditions of formation; qualitative state; TDS; Dnipro River basin; підземні води; безнапірні водоносні горизонти; умови формування; якісний стан; мінералізація; басейн Дніпра
• Онлайн доступ: http://geojournal.igs-nas.org.ua/article/view/273768
• Назва журналу: Geological journal

The article deals with the chemical composition of uppermost aquifers water in the Dnipro River basin. Its study is necessary not only in connection with the implementation the requirements of the EU Water Framework Directive methodological documents in the groundwater monitoring, but primarily because of water supply from these aquifers to rural areas. Unconfined aquifers water is characterized by a complex and heterogeneous chemical composition due to natural and anthropogenic factors. Natural hydrochemical zoning is distinctly visible on the territory of the Dnipro basin. A number of chemical elements and compounds in the water are contained in concentrations exceeding the standards for drinking water established by the State sanitary norms and rules 2.2.4-171-10 “Hygienic requirements for drinking water intended for human consumption” in the natural state. In addition, unconfined aquifers are subject to significant anthropogenic impact, as they are unprotected from pollution. Comparison of the data on total dissolved solids (TDS) and anionic composition of groundwater obtained during hydrogeological surveys in the period 1965–1975 and 2009–2013 on three sheets of the hydrogeological map (scale 1:200,000) in different sub-basins of the Dnipro River showed the widespread deep changes in groundwater chemical composition. In addition to a significant anthropogenic pressure, groundwater is significantly affected by climatic factors. Over a forty-year period, TDS in the north of the Dnipro basin increased by 50 %, in the central and southern parts – twice, due to an increase in the content of sulfates and chlorides. Within the analyzed areas in the Middle and Lower Dnipro sub-basins, nitrate pollution of unconfined aquifers is almost widespread. Thus, in a large area, waters of these aquifers are unsuitable for drinking water supply due to the excessive content of chemical elements and compounds of natural and anthropogenic origin. Therefore, one of the priorities of the post-war reconstruction of Ukraine should be the transfer of the rural population to water supply from protected confined aquifers and the improvement of sanitary conditions in rural areas.