CHEMICAL COMPOSITION AND IRRIGATION QUALITY OF GROUNDWATER FROM INDIVIDUAL WATER SOURCES IN THE CHELYABINSK REGION

Purpose: to assess the groundwater quality used for irrigation of individual plots of residents of the Chelyabinsk region. Materials and methods. 432 samples were collected in 2012–2024 in wells and boreholes on the territory of private land plots. 31 indicators of water composition were determined; the median, quartiles, and proportion of samples exceeding standards were calculated. Standards are: 5 indicators of the domestic soil-reclamation classification and 9 international ones (residual sodium carbonate, %Na, Na and Mg adsorption coefficients, Kelly coefficient, permeability index, potential salinity, synthetic harmfulness coefficient K, Staebler irrigation coefficient Ka. The data were visualized using the Piper diagram and pie graphs. Results and discussion. The waters with a hydrocarbonate type by anion composition and a calcium or mixed with Ca and Mg type by cation composition predominate in the territory of the Chelyabinsk region. In 25 % of samples, the excess of the standard for nitrates was recorded. In general, the waters have a good permeability index (the share of unsuitable and harmful samples – UHS – 2.5 %), low potential salinity (3.5 %) and the salinization risk by the mineralization indicator (4.2 %), low risk chloride salinity (3.0 %), low sodium content (UHS for four different indicators – 3.0–11.6 %) and magnesium (3.2–19.9 % for 2 indicators). According to the synthetic harmfulness coefficient, the UHS was 37.3 %, and according to the irrigation coefficient Ka – 1.2 %. The UHS with a high content of microelements was: for Ba – 74.3 %, Cd – 36.1 %, F – 35.0 %, Fe – 25.8 %, Mn – 15.8 %, Pb – 6.5 %, Sr – 1.4 %, Ni – 0.63 %, Zn – 0.56 %, Cu – 0.00 %. Conclusion. According to most indicators, groundwater in individual plots in the Chelyabinsk region turned out to be predominantly suitable for use for irrigation purposes.