Hydrochemical assessment of groundwater using multivariate statistical methods and water quality indices (WQIs)

Abstract

Groundwater quality assessment is crucial for the sustainable management of water resources in arid regions, where groundwater is the primary source of water supply and increasing demand raises concerns. The study area in Southwest Algeria relies heavily on groundwater as a source of water supply, and the increasing demand for freshwater raises concerns about the quality of groundwater. To assess the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region, multivariate statistical methods, geochemical modeling and water quality indices were employed. The study revealed that the groundwater samples could be classified into four water groups using hierarchical cluster analysis Q mode (HCA), namely Ca–Mg–HCO3, Ca–Mg–Cl–SO4, Ca–SO4 and Na–Cl. Factor analysis was used to identify the main factors controlling the study area’s hydrochemical processes. The results indicated that water–rock interaction, reverse ion exchange and anthropogenic pollution were the main hydrochemical processes affecting groundwater chemistry. The water quality index indicated that the groundwater was suitable for human consumption, with only 2.32% of the samples being unsuitable. Additionally, the groundwater was suitable for agricultural use, but salinity control was necessary. The saturation index values showed that the groundwater was supersaturated with aragonite, calcite, dolomite, anhydrite and gypsum, and undersaturated with halite. Ca-smectite, Mg-smectite and kaolinite were identified as the primary processes controlling the chemical composition of groundwater. The application of multivariate statistical methods, geochemical modeling and water quality indices provided a comprehensive understanding of the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region. The findings of the study can serve as a useful basis for future studies on groundwater quality assessment in the region.

Origin and evolution of groundwater in the Goharzamin mine area using hydro-geochemical and isotopic analyses

“…Groundwater chemical composition involves the spatial and temporal variations due to precipitation, water-rock interaction, evaporation, redox reactions, recharge water quality, reactions of ion exchange, sorption, dissolution, climate, the grade of chemical weathering of different types of rock, mixing processes, etc. Hydrogeochemical analysis techniques in combination with stable isotope analysis (e.g., 18 O and 2 H), radioisotopes (e.g., 3 H and 14 C), and statistical techniques (e.g., Principal-Component-Analysis (PCA) and Hierarchical-Cluster-Analysis (HCA)) are often applied as effective methods to provide significant information regarding similarities among groundwater samples and/or hydrochemical variables, the groundwater residence times in aquifers, the source of groundwater in reservoirs, the groundwater movement's rate and direction, hydrochemical reactions in aquifers, climatic conditions during the recharge, hydraulic connection between different water sources, geological structure of aquifers, and anthropogenic impacts on aquifers (Zouari et al 2011;Fang 2019;Acikel and Ekmekci 2021;Okofo et al 2022;Zhao et al 2022;Nayak et al 2023;Ju et al 2024;Hamma et al 2024; amongst many others). These analysis techniques play a crucial role in enhancing our comprehension of hydrogeological systems.…”