Physicochemical Characteristics of Groundwater Around Offa Garage Dumpsite Axis, Ilorin, Kwara State, Nigeria

Abstract

Groundwater contamination from indiscriminate solid waste disposal remains a significant environmental and public health concern in many Nigerian urban centers, particularly where domestic wells are situated near open dumpsites. The objective of this paper was to evaluate the physicochemical characteristics of groundwater around the Offa Garage dumpsite axis, Ilorin, Kwara State, Nigeria using appropriate standard procedures. The results showed that groundwater quality in the study area was characterized by mean pH of 7.08 ± 0.18, electrical conductivity of 529.7 ± 4.90 µS/cm, total dissolved solids of 267.3 ± 7.82 mg/L, turbidity of 1.35 ± 0.07 NTU, nitrate of 0.23 ± 0.06 mg/L, and biochemical oxygen demand of 58.6 ± 4.78 mg/L. Mean lead and cadmium concentrations were 0.0068 ± 0.0010 mg/L and 0.0022 ± 0.0004 mg/L, respectively. Significant spatial variations (p ≤ 0.05) were observed in several physicochemical parameters and heavy metals, indicating the influence of dumpsite leachate on groundwater quality. Although most measured parameters complied with World Health Organization and Nigerian Standard for Drinking Water Quality limits, elevated concentrations of selected contaminants suggest localized groundwater impairment associated with leachate infiltration. The contamination pattern demonstrates the vulnerability of groundwater resources in the study area to waste disposal activities and highlights potential long-term public health risks. The study concludes that the Offa Garage dumpsite exerts a measurable influence on surrounding groundwater quality. Improved waste management practices, routine groundwater monitoring, community sensitization, and enforcement of safe separation distances between dumpsites and domestic wells are recommended to safeguard groundwater resources and public health.