Hydroecological Assessment of Brackish Groundwater in The Republic of Karakalpakstan

The Aral Sea crisis has severely impacted water resources in the Republic of Karakalpakstan, making groundwater a critical alternative source for drinking and irrigation. This study presents a hydroecological assessment of brackish groundwater in the Karauzyak district based on field investigations conducted in 2025. Results showed that groundwater mineralization ranges from 2.1 to 4.8 g/L (predominantly 2.2–3.8 g/L), classifying the water as brackish to highly brackish. The dominant hydrochemical type is sodium-chloride and mixed sodium-sulfate-chloride. Most samples exhibited pH values of 7.1–8.3, moderate to high hardness (6.5–26.5 mg-eq/L), and elevated sulfate and chloride levels. Concentrations of toxic microelements (Pb, Cd, As, Hg, etc.) remained below maximum permissible limits. However, the overall salinity significantly restricts direct use for drinking water supply and limits agricultural application without additional management. Piper diagram analysis revealed distinct hydrochemical facies, reflecting the influence of natural salinization processes, irrigation seepage, and evaporative concentration under arid conditions. The findings highlight both the potential and limitations of local groundwater resources and underscore the need for desalination technologies, improved drainage, and continuous monitoring to ensure sustainable use in the Aral Sea region.