ГЕОХІМІЧНА ХАРАКТЕРИСТИКА РІЧКОВИХ ТА ҐРУНТОВИХ ВОД (Зовнішня зона Передкарпатського прогину)

Abstract

Geochemical peculiarities of river and groundwaters of the Outer zone of the Precarpathian deep have been established. It is revealed that the main feature of the distribution of salt composition indicators in the Dniester River and its influxes is hydrochemical zonality, which does not depend on the flow direction of the rivers, but is consistent with the physics-geographical and geological features of the area to which the man-made factor is imposed. There is an increase in concentrations of sulfate, calcium in the left bank confluent of the river Shchyrka. The waters from the Tysmenytsya, Kolodnitsa and Dniester rivers in the village Kolodrubi are characterized by the highest amounts of sodium and chlorides and are sodium chloride-hydrocarbonate composition. The water composition of the Dniester River (Rozvadiv village), its confluents Bystrytsia and Letnyanka are hydrocarbonate calcium (sodium-magnesium-calcium), Shchyrka, Vereshchitsa – sulfate-hydrocarbonate calcium (magnesium-calcium). The index of biochemical oxygen consumption for 5 days in the waters of Tysmenytsya River reached 4.5 mg O2/dm3, while in other rivers it was 0.70‒3.20 mg O2/dm3. The content of O2 soluble in the waters of the river Vereshchytsya was 0.29 mg/dm3, the value of biochemical oxygen consumption was 11.4 mg O2/dm3. In the chemical composition of river waters, there is an increase in the concentrations of sodium, potassium and chloride ions from the left bank to the right bank confluents of the Dniester. In the left-bank confluents, in the chemical composition of water dominate the contents of calcium and hydrocarbons ions. The heterogeneity of the lithological composition, the instability of the thickness of the aquifer both in the horizontal and vertical directions, and the different technogenic influence form the irregularity of pollution and its local distribution in groundwater.