Groundwater Quality Assessment and Geochemistry in the Guerrara Region, Algeria

Abstract

The investigation in question involved the collection of 85 groundwater specimens from Complex Terminal aquifer wells in the Guerrara region. The purpose was to appraise the chemical quality of the water and examine the hydro chemical operations that influence the mineral content of the groundwater. The data obtained revealed that the water samples showcased a slightly alkaline pH and had high mineral concentrations. The order of decreasing concentration of the mainstream ions present in the water is as follows: sulfate ion (SO4-2), chloride ion (Cl-), sodium ion (Na+), calcium ion (Ca+2), bicarbonate ion (HCO3-), magnesium ion (Mg+2), nitrate ion (NO3-), and potassium ion (K+). The Geographic Information System (GIS) was utilized to visually represent the spread of parameters across the area under study. Hierarchical Component Analysis (HCA) was employed to identify four distinct geochemical water facies: SO4-Na-Ca, SO4-Na-Cl, SO4 with no dominant cation, and SO4-Cl-Na-Ca. Principal Component Analysis (PCA) was implemented to categorize water parameters into three principal components (PCs) that represented 72.66% of the overall variance. The analysis revealed that the foremost sources of water mineralization are the dissolution of evaporitic and carbonate rocks, as well as anthropogenic activities. The Saturation Index indicated that the water samples were supersaturated with respect to calcite and dolomite, while being undersaturated with regard to gypsum, anhydrite, and aragonite. Geochemical plots demonstrated that evaporation and the interaction between rocks and water, particularly through the base ion exchange process, are the key mechanisms influencing groundwater mineralization.