Abstract
The article analyses the monitoring data of the groundwater chemical composition in nine observation wells on the territory of the St. Sophia Cathedral ensemble, obtained during 2012-2024. The results of the groundwaters chemical composition analysis of the Reserve's territory revealed exceedances of the standard indicators (total mineralization, chlorides, ammonium, sodium and potassium, pH) in the waters of a number of wells. It was found that the water from the wells located in the northern and western parts of the Reserve's territory has either a weakly expressed trend towards an increase in the concentration of groundwater chemical composition components and total mineralization, or no such trend at all, while the water from the wells located in the eastern, southern and central parts of the Reserve's territory has a significant trend towards an increase in the concentration of both individual components and total mineralization. The facts of exceeding the established standards in the waters of a number of wells in the Reserve by various indicators may have natural and technogenic causes, while the trends towards a constant, significant increase in a number of water components and overall mineralization have technogenic causes. It was determined that the groundwater of the reserve territory is divided into two groups by its composition: mixed type (with a slight predominance of hydrocarbonate ions) and calcium chloride.