Identification of the hydrogeochemical processes and assessment of groundwater quality using Water Quality Index (WQI) in semi-arid area F'kirina plain eastern Algeria

Groundwater in the F'kirina plain of eastern Algeria plays a crucial role in human life and agriculture. The present study was conducted to analyze the hydrogeochemical characteristics of this plain's groundwater in a semi-arid region. Twenty samples were collected (in June 2022) and tested for ions, such as Na+, K+, Mg2+, Ca2+, NH4+, Cl−, HCO3−, NO3−, NO2−, SO42−, Br−, Sr2+ as well as temperature, pH, electrical conductivity (EC) and total dissolved solids (TDS). The results were analyzed using the XLSTAT software with Principal Component Analysis (PCA), Piper, and Gibbs diagram. Four hydrochemical facies were identified, reflecting the diverse processes influencing water chemistry in the study area, such as, chloride-calcium, sodium-bicarbonate-calcium and sulfate–calcium, defining the sample characteristics. The study also assessed water quality using the Water Quality Index (WQI) based on WHO guidelines and found that 50% of wells exceeded the recommended limits for major elements. (PCA) identified geological and anthropogenic factors that influence water chemistry, with geological substrate and agricultural practices contributing to groundwater degradation in the area. The novelty of this research lies in its integrated approach, combining multivariate statistical analysis, hydrogeochemical diagrams, and WQI to provide a comprehensive assessment of groundwater quality. This multidisciplinary methodology effectively identifies both natural geochemical processes and anthropogenic influences, offering innovative insights into how evaporation and water–rock interactions shape groundwater chemistry in a semi-arid context. The findings not only enhance understanding of groundwater dynamics in the F'kirina plain but also provide a practical framework for sustainable water resource management in similar arid and semi-arid regions.