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

¹ Laboratory of Engineering Sciences and Applications (LSIA)Materials Science, Energy and Environment (SM2E) Research team, ENSAH / Abdelmalek Essaâdi University, Al Hoceima, Morocco
² Laboratory of Research and Development in Engineering Sciences, Faculty of Sciences and Techniques of Al-Hoceima (FSTH), Abdelmalek Essaâdi University, Tetouan, Morocco
³ Department of Geology, Applied Geosciences and Geological Engineering Research Team, FSTH, Abdelmalek Essaâdi University, Al Hoceima, Morocco
⁴ Environmental Management and Civil Engineering Research Team, Laboratory of Applied Sciences, ENSAH, Abdelmalek Essaâdi University, Al Hoceima, Morocco
⁵ Department of Environment, Laboratory of Functional Ecology and Environment Engineering, Faculty of Sciences and Techniques, University Sidi Mohamed Ben Abdellah, Fez, Morocco

^* Corresponding author: abourjila@uae.ac.ma

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⁺, Mg²⁺, Ca²⁺, NH₄⁺, HCO₃^-, NO₃^-, NO₂^-,Cl^-, SO₄^2-, PO₄^3-, and SiO₂. 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 Mg²⁺, 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.