Assessment of groundwater and storage water quality contamination at the University of Benin campus, Southern Nigeria

Assessing the quality of groundwater is essential for safeguarding public health and environmental sustainability, particularly in the context of developing countries where access to clean water is often limited. For this reason, this study evaluates the physico-chemical, heavy metal, and microbial characteristics of groundwater from borehole well heads (groundwater samples) and groundwater in storage tanks (storage water samples) from the University of Benin campus community and its surrounding areas, Benin City, Nigeria, to determine potential contamination sources and propose mitigation strategies. Thirty-eight samples (19 wellhead and 19 storage) were analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), salinity, trace metals (Fe, Zn, Cu, Mn, Ni, Cr, Co, Pb, and Cd), and bacteriological indicators (total coliform count and Escherichia coli) using standard methods. The pH ranged from 6.04 to 8.2, while EC and TDS ranged from 68–198 µS/cm and 24–97 mg/L, respectively, below World Health Organization (WHO)/Nigerian Standard for Drinking Water Quality (NSDWQ) permissible limits. Fe concentrations (0.352–1.863 mg/L) exceeded the NSDWQ guideline value (0.3 mg/L) in all samples, and Ni exceeded the NSDWQ limit (0.02 mg/L) in 36/38 samples (but remained below the WHO health-based value of 0.07 mg/L). Pb exceeded 0.01 mg/L in 8 samples (maximum 0.1025 mg/L), while Cd was below the detection limit in all samples. Total coliform counts were < 10 CFU/100 mL; however, E. coli was detected in 10 of the 20 samples analysed for microbiology (maximum 20 CFU/100 mL), indicating intermittent faecal contamination. The results suggest mixed geogenic (lateritic/ironstone leaching) and anthropogenic (sanitation and infrastructure-related) inputs. We recommend enforcing the established minimum 30 m setback between boreholes and septic systems/latrines/soakaways, routine tank cleaning/disinfection, plumbing maintenance, and regular monitoring.