International Journal of Environment and Climate Change

The Kantché Department in southwestern Zinder, Niger, depends on groundwater for domestic and socio-economic activities, but the factors affecting its chemical composition remain insufficiently characterised. This study investigated groundwater hydrochemistry and the principal processes associated with mineralisation using physicochemical measurements, a Piper diagram and principal component analysis (PCA). Groundwater samples were obtained from 25 water points, and PCA was applied to 11 physicochemical variables. The measured pH ranged from 4.6 to 7.76, with a mean of approximately 6.2, while electrical conductivity varied from 23 to 404 µS/cm, with a mean of 100.92 µS/cm. These results indicate generally low mineralisation and a tendency towards slightly acidic conditions. The predominant hydrochemical facies was calcium–magnesium bicarbonate. The first three principal components explained 47.58%, 17.32% and 11.91% of the variance, respectively, accounting for 76.81% cumulatively. Electrical conductivity was positively associated with bicarbonate, calcium and sulphate, whereas ferric iron showed comparatively weak correlations with most parameters. The PCA projections differentiated groups of physicochemical variables and water points with similar hydrochemical characteristics. The observed associations suggest that water–rock interactions, including weathering and mineral hydrolysis, are important influences on groundwater composition, alongside possible surface-derived inputs and redox-related processes. The findings provide a hydrochemical basis for interpreting groundwater variability in Kantché and can inform subsequent assessment and protection of this resource.