Exploring salinity origins in the Ghiss-Nekor aquifer, northern Morocco: A multivariate statistical analysis

Abstract

The Ghiss-Nekor coastal aquifer is characterized by high salinity stemming from multiple sources, remains poorly investigated. This study aims to address this knowledge gap by employing both univariate (descriptive statistics) and multivariate statistical analyses, including correlation matrix and principal component analysis (PCA). Groundwater samples were collected from 52 sites across the study area and meticulously analyzed for pH, TDS, EC, and the ions such as Na + , K + , Mg 2+ , Ca 2+ , NH 4 + , HCO 3 - , NO 3 - , NO 2 - ,Cl - , SO 4 2- , PO 4 3- , and SiO 2 . Descriptive statistics, notably standard deviation (SD), highlight the diverse sources contributing to salinization, among which seawater intrusion (SWI) emerges as a significant factor. Correlation matrix analysis underscores multiple pathways for salinization, implicating SWI, salt dissolution, chemical weathering, secondary salt leaching, and anthropogenic activities. PCA elucidates 81.05% of the total variance in physicochemical parameters, with strong loadings observed for EC, Na + , Cl - , and Mg 2+ , corroborating the influence of SWI and suggesting evaporation processes. Moreover, PCA reinforces the potential influence of both geogenic and anthropogenic factors in salinization within the study area. This comprehensive investigation provides valuable insights into the elevated salinity levels observed in the Ghiss-Nekor aquifer, contributing to a deeper understanding of its hydrogeochemical dynamics.