SOIL INFLUENCE ON THE CHEMICAL COMPOSITION OF GROUND WATERS IN THE REPUBLIC OF TATARSTAN

Abstract

The upper section part of the Republic of Tatarstan comprises complexes of poly-facial Middle and Upper Permian, Mesozoic, and Pliocene-Quaternary sediments. Surface and groundwater here is characterised by wide variations in composition and mineralisation due to natural and technogenic factors. The most important natural factor is the interaction of atmospheric precipitation and its derivatives with the soils and rocks of the section. To assess the scale of this interaction, water extracts from the main soil varieties based on distilled and melt snow water were analysed. The composition of aqueous extracts was compared with that of the least mineralised (up to 250 mg/l) spring water. The compounds delivered to the upper part of the section by soils include organic matter, nitrogen compounds in nitrite and ammonium forms and, to a lesser extent, iron and manganese. It is shown that the composition of groundwater outside zones of technogenic impact is largely determined by the interaction of atmospheric precipitation with the soil cover. This is explained by the fact that water extracts from soil samples have a mineralisation of over 100 mg/l, while the minimum mineralisation of spring water is 150—200 mg/l. Soils within forests and meadows are characterised by the maximum mineralising role. The soils of river valleys and cultivated fields contribute to water mineralisation to a lesser extent. The maximum amount of mineral and organic complexes that are readily soluble in water was found in blacksoils and grey forest soils, while their minimum was determined in grey-coloured sod-podzolic soils.

Keywords

• почвенный покров
• грунтовые воды
• водные вытяжки
• выщелачивание
• черноземные и дерново-подзолистые почвы