Quality Assessment and Hydrochemical Facies of Groundwater in Al-Qarma District, West of Baghdad, Iraq: Implications for Drinking and Irrigation

The current study presents a comprehensive evaluation of groundwater quality in the Al-Qarma district, located west of Baghdad, based on twenty samples collected from shallow wells in September 2024. The pH, temperature, electrical conductivity, Total Dissolved Solids, and total hardness, along with main ion concentrations (Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄²⁻, Cl⁻, HCO₃⁻, and NO₃⁻), were measured and compared to national and international guidelines. Almost all samples exceed drinking-water regulations for TDS, EC, TH, Cl⁻, and SO₄²⁻, making them unsafe for direct consumption without treatment. Irrigation suitability, as measured by the Sodium Adsorption Ratio, Residual Sodium Carbonate, salinity hazard classes, and the Wilcox diagram, shows generally low sodium hazard but high to very high salinity, resulting in mixed classifications ranging from good to unsuitable for crop irrigation. Piper, Durov, and Schoeller diagrams indicate that the primary water types are Ca-Mg-SO₄ and Na-Cl, suggesting mineral dissolution (particularly gypsum and halite), high evaporation rates, and anthropogenic influences such as agricultural runoff. Gibbs plots reveal evaporation and rock-water interactions as the primary regulators of water chemistry. The study recommends not using this groundwater for drinking purposes but rather for irrigating crops.