Evaluation of drinking water suitability in rural primary school environments: linking hydrochemistry, multivariate analysis, and water quality indices in Northern Uganda.

Groundwater is the dominant source of drinking water in rural Sub-Saharan Africa, yet its suitability in school environments is rarely evaluated using process-based approaches. This study assesses groundwater sources used by government aided primary schools in Vurra Subcounty, Northern Uganda, integrating hydrochemical analysis with principal component analysis (PCA), hierarchical cluster analysis (HCA), and Water Quality Index (WQI) assessment. Water sources exhibited slightly acidic to near-neutral conditions (pH 5.59-7.17) and low mineralization (TDS: 4-356 mg L-1), consistent with dilute basement aquifers. PCA indicates that hydrochemical variability is primarily controlled by carbonate-mediated water-rock interaction (PC1: 41.0%), while redox-sensitive mobilization of iron and manganese accounts for secondary variability (PC2: 22.8%). WQI values ranged from 27.07 to 219.96, with 55% of sites classified as poor to very poor. Sites with elevated WQI values correspond to higher Fe and Mn concentrations rather than total dissolved solids. These results indicate that groundwater suitability in the study area is constrained by trace metal dynamics within an otherwise low-mineralization system. The findings highlight the need for targeted monitoring and treatment strategies that explicitly address redox-driven contaminants in rural water supply systems.