Physicochemical Characteristics, Heavy Metal Levels, Microbiological Quality and Public Health Risks in Groundwater from Malete, Kwara State, Nigeria

Abstract

Groundwater remains a major source of domestic water supply in many rapidly urbanizing communities; however, indiscriminate solid waste disposal through open dumping and poor waste management practices poses serious threats to groundwater quality and public health.  Consequently, the objective of this paper was to assess the physicochemical characteristics, heavy metal levels, microbiological quality and public health risks in groundwater from Malete, Kwara State, Nigeria using appropriate standard procedures including structured questionnaires.  The results revealed significant contamination in water sources located closer to the dumpsite, particularly JIK, JAK 1, Well Water 1, and Well Water 2. Lead, chromium, and cadmium concentrations reached 0.163, 0.700, and 0.055 mg/L, respectively, exceeding WHO guideline limits (p < 0.001). These sources recorded WQI values ranging from 400 to 493, indicating that the water was unsuitable for drinking, while HI values (7.95–9.22) suggested severe potential health risks. Microbiological assessment showed elevated total coliform counts up to 1.2 × 10⁵ CFU/mL, with Escherichia coli detected in contaminated wells. Exponential decay modelling predicted minimum safe distances of 575 m, 729 m, and 789 m for lead, chromium, and cadmium migration, respectively. Groundwater sources near solid waste disposal sites in Malete are highly vulnerable to heavy metal and microbial contamination, presenting significant public health concerns. Improved solid waste management practices, routine groundwater quality surveillance, enforcement of environmental regulations, and restriction of borehole and well construction near dumpsites are recommended to minimize contamination risks.