Гидрохимическая характеристика и качество подземных вод Сосновского района Челябинской области для целей орошения

Abstract

Abstract. The purpose of the study was to assess the quality of groundwater used for irrigation of individual plots of land, belonging to the residents of the Sosnovskiy district of the Chelyabinsk region. Material: 73 samples taken in wells and boreholes on the territory of private land plots, villages, villa communities and garden non-profit partnerships. Methods: 30 indicators of water composition were determined (common indicators – 6, major ions and carbonate ion – 8, compounds of nitrogen, phosphorus and organic matter – 5, heavy metals and silicon – 11) using capillary electrophoresis, atomic absorption, potentiometry, spectrophotometry and conductometry. Statistical analysis included: estimation of means with 95 % confidence intervals (95 % CI) calculated by bootstrap (Kaplan – Meier method was used for censored observations), relative frequencies (in percent) with 95 % CI (Jeffreys method and simultaneous CI by Wilson). Data was visualized using Piper’s and Gibbs’ diagrams. Software: PAST, Scout 2008, R, DescTool, GW_Chart, KyPlot, QGIS. Results. On the territory of the Sosnovsky district of the Chelyabinsk region, (Ca2+–Mg2+ and HCO3––CO32–) type groundwater prevails with a pH 7.39 (95 % CI: from 7.30 to 7.48) and a TDS 651 mg/dm3 (95 % CI: from 598 to 720). Using Piper and Gibbs diagrams, it was established that the leading processes of the water chemical composition formation are: 1) the dissolution of the calcite-dolomite series’ minerals of sedimentary rocks, 2) the dissolution and the ion exchange of feldspars in the composition of granites with calcite. For mineralization and risks of chloride salinization, sodium salinization, magnesium salinization and soda formation, the proportion of samples with quality for irrigation purposes I and II category is 65.7 %. There are excesses of standards in the concentration of NO3- (24.7 % of samples), Ba (68.3 %), Cd (30.4 %), Fe (15.3 %), Mn (12.9 %), Pb (6.3 %).