Assessment of mineralization processes and salinity risk in the Terminal Complex aquifer, Cheggua, Southeastern Algeria

ABSTRACT

Graphical showing groundwater salinization in the Termal Complex aquifer (Cheggua SE Algeria); the results show severe miniralizattion with high electrical conductivity,total dissolved solids and salinity .

This study evaluates groundwater quality and salinization risk in the Terminal Complex aquifer of Cheggua, southeastern Algeria, using physicochemical data from 27 groundwater wells. The analyzed parameters included pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, and turbidity. Results indicate a highly mineralized aquifer, with EC values ranging from 4,054 to 13,980 μS/cm, TDS from 2,027 to 6,994 mg/L, and salinity between 2.15 and 8.09 psu. Mean EC (5,980 μS/cm), TDS (2,990 mg/L), and salinity (3.25 psu) values confirm widespread saline groundwater conditions. Groundwater pH was neutral to slightly alkaline (mean 7.75), while turbidity remained generally low (median 1.2 FNU). Multivariate statistical analyses revealed strong positive correlations among EC, TDS, and salinity (r > 0.95), whereas turbidity exhibited a moderate negative correlation with mineralization (r = −0.49). Multiple linear regression accounted for 85% of salinity variability (R2 = 0.85). Hierarchical cluster analysis identified four distinct hydrochemical groups reflecting increasing mineralization levels and marked spatial heterogeneity. One-way analysis of variance demonstrated significant differences in EC, TDS, and salinity across depth categories (p < 0.05). Geographic Information Systems (GIS)-based spatial analysis delineated vulnerable zones characterized by TDS values exceeding 4,000 mg/L, highlighting the combined effects of saline intrusion, evaporite dissolution, and groundwater overexploitation. These findings provide valuable insights into groundwater salinization processes and support sustainable groundwater management in arid and hyper-arid regions.