The Study of Groundwater Salinization Mechanisms: A Case Study of the Remila Basin, Northeastern Algeria

This study provides a thorough hydrogeochemical analysis of the Remila basin in northeastern Algeria, addressing critical water resource issues. The groundwater exhibits diverse chemical facies, mainly calcium-sulfate (Ca-SO₄) and calcium-bicarbonate (Ca-HCO₃) types, reflecting complex geology and water-rock interactions. Groundwater mineralization is primarily driven by evaporitic mineral dissolution, such as gypsum and halite, with strong correlations between electrical conductivity and major ions. Ion exchange processes, indicated by Na⁺/Cl⁻ ratios and relationships between calcium, magnesium, and sodium, significantly influence groundwater chemistry. Elevated strontium levels, especially in rapid runoff areas, suggest an influence of evaporitic formations and celestite dissolution, supported by Sr²⁺/Ca²⁺ ratios exceeding 1%. Lithium concentrations indicate prolonged water-rock interactions and deep aquifer systems. Principal component analysis (PCA) reveals that natural salinization processes primarily driven by the dissolution of evaporitic minerals account for 44.65% of the total variance (PC1), while anthropogenic pollution, particularly nitrate contamination from agricultural sources, contributes 13.73% (PC2). Groundwater is generally undersaturated with major minerals, indicating ongoing dissolution processes, and spatial variations in water quality parameters emphasize the combined influence of geological factors and anthropogenic activities on the aquifer system