Seasonal Assessment of the Physicochemical Parameters of Groundwater in the Town of Houndé, Burkina Faso

Abstract

Groundwater is the principal source of drinking water for many residents of Houndé, Burkina Faso. This study examined the physicochemical and hydrochemical quality of groundwater in the Houndé region, Burkina Faso, where residents relied heavily on wells and boreholes for their drinking-water supply. Five (05) water sources, comprising two (02) boreholes and three (03) wells, were analysed during two sampling campaigns: one in the rainy season (August 2024) and the other in the dry season (March 2025). The measured parameters included temperature, pH, electrical conductivity, turbidity, total dissolved solids (TDS), hardness, major ions, and several trace metals. The presence of these parameters in water originating from geological formations is a characteristic of groundwater observed in most regions of Burkina Faso. Temperatures varied little, ranging from 26.1°C to 26.8°C throughout the year. Sample pH ranged from 5.4 to 7.8, with nearly 60% of the values within the WHO range of 6.5–8.5. The remaining 40% showed slightly acidic pH values, although this did not significantly affect water quality. Electrical conductivity was higher in the boreholes (292–397 µS/cm) than in the wells (21.3–67.9 µS/cm), while remaining below the WHO standard of 1,000 µS/cm. The conductivity values observed in the boreholes could be associated with human activities near these water sources and inadequate protective measures, which may have contributed to the infiltration of dissolved substances. Turbidity was generally low, except in wells 2 and 3, where values exceeded the WHO threshold of 5 NTU, possibly indicating an influence from human activities. Nitrate concentrations were low (3.54–18.3 mg/L). Metal concentrations were generally low, with a temporary exceedance of the WHO guideline value for total iron (0.3 mg/L). The ionic balance error remained below 10%, in accordance with WHO recommendations, thereby supporting the validity of the analyses. The Water Quality Index (WQI) ranged from 13.97 to 45.18, placing all samples in the excellent category for human consumption. The Piper and Schoeller–Berkaloff diagrams revealed predominantly calcium bicarbonate and calcium–magnesium hydrochemical facies, indicating that mineralisation was primarily influenced by water–rock interactions.