Evaluation of groundwater quality in the bouanane plain using the groundwater pollution index, nitrate pollution index, and microbiological indicators

Abstract Groundwater provides a vital component of water supplies in semi-arid environments, wherein its quality directly influences ecosystem stability and human well-being. This investigation presents the first complete evaluation of groundwater quality in the Bouanane basin by implementing an innovative PCA–GIS framework combined with established hydrochemical indices, thereby enhancing the discrimination of pollution sources beyond what conventional methods typically allow. Nine groundwater samples collected in April 2024 were analysed for major ions and microbiological indicators. Water quality was subsequently evaluated using (PIG), (NPI), and a USEPA based Human Health Risk Assessment. PIG values ranged from 1.12 to 3.03 demonstrating that 44% of samples come inside the very highly polluted classification, primarily due to geogenic mineralization associated with carbonate and evaporitic formations. Conversely, NPI values (− 0.98 to − 0.25) indicate negligible nitrate contamination and minimal human influence. Health risk indices for both children and adults remained less than 1, suggesting no significant risk to public health. Although most samples complied with World Health Organization WHO (World Health Statistics, Monitoring Health for the SDGs, Sustainable Development Goals, 2017) drinking water guidelines, Staphylococcus aureus was detected at 22% of sampling locations, underscoring the need for periodic sanitary monitoring. Overall, the findings demonstrate that groundwater chemistry within the basin is predominantly shaped by natural geochemical processes. Furthermore, the integrated PCA–GIS framework proved to be a robust and efficient tool for groundwater quality diagnosis. This pioneering investigation establishes an essential scientific baseline for the Bouanane basin and provides a foundational reference for evidence-based water resource management amid rising climatic and anthropogenic pressures.