Features of chemical composition of drainage waters of St Andrew's Church and Kyiv-Pechersk Lavra territories

The article examines the features of the chemical composition of drainage system waters and groundwater in the area adjacent to St Andrew’s Church and drainage system Kyiv-Pechersk Lavra. Hydrochemical water types were determined, a preliminary assessment of ion-exchange processes was performed using chloride-alkaline indices (CAI, CAI2), and a preliminary analysis of the probable mechanisms of formation of the chemical composition of the studied waters was carried out by comparing the major cations and anions. A comparative analysis was made of the chemical composition of drainage waters of the St Andrew’s Church territory with groundwater from observation wells (Quaternary and Paleogene aquifers), as well as with the drainage waters of Kyiv-Pechersk Lavra. The drainage waters of St Andrew’s Church and Kyiv-Pechersk Lavra are similar in composition to each other and to the groundwater of a number of wells in hydrochemical type, namely chloride-calcium or mixed-calcium with a significant proportion of chloride ions in the chemical composition. In the drainage waters of St Andrew’s Church and Kyiv-Pechersk Lavra, reverse cation exchange processes were established (Ca and Mg are displaced from rocks by Na and K). In the waters of other wells of the St Andrew’s Church territory, direct cation exchange processes were established (Na and K are displaced from rocks by Ca and Mg). Apparently, there is an anthropogenic source of input of Cl- into the groundwater of a number of wells and the drainage waters of St Andrew’s Church and Kyiv-Pechersk Lavra. There is also an alternative source of input of Ca2+ ions, or an input of Na+ into the soils and ion exchange of Na+ for Ca2+ during infiltration through the rock layer.