Heavy Metal Contamination and Cancer Risk Assessment in Groundwater Near Dumpsites: Health Implications for Vulnerable Populations in Nigeria

Nigeria is experiencing a growing threat of groundwater pollution due to insufficient waste management practices. This study aimed to assess the levels of heavy metal contamination in groundwater near the Ikhueniro and Otofure dumpsites in Benin City, Edo State, Nigeria, and to evaluate the associated health risks. Water samples were collected from boreholes in residential areas surrounding both dumpsites during both the rainy and dry seasons, yielding 144 samples. These were analyzed for concentrations of lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), iron (Fe), nickel (Ni), and copper (Cu) using standard protocols. The results indicated that Fe, Cu, Zn, and Ni were the most prevalent metals, with Fe showing the highest concentrations at both sites. The hazard index (HI) and cancer risk (CR) calculations highlighted serious health risks, particularly for children and infants. Specifically, the cumulative cancer risk for Pb, Cr, and Ni exceeded internationally recognized safety limits, indicating a significant potential for long-term health impacts. The study concluded that the proximity to these dumpsites significantly deteriorates groundwater quality, emphasizing the need for stricter environmental controls and public health interventions.