G. Ogbeide

This study investigates the impact of urban runoff on heavy metal concentrations in Ikpoba River, focusing on water, sediment, and fish gonads. Two sampling stations, upstream and downstream, were selected to assess variations in contamination levels. In August, downstream water samples exhibited significantly elevated lead (Pb) levels (0.037 mg/L) compared to upstream (0.029 mg/L). Similarly, downstream cobalt (Co) concentrations (0.02 mg/L) were higher than upstream (0.016 mg/L). These findings indicate substantial contamination downstream, potentially from industrial sources. Sediment analysis highlighted significant downstream contamination. Lead (Pb) levels in downstream sediments (5.208 mg/kg) were markedly higher than upstream (0.362 mg/kg) in August. Cobalt (Co) also displayed elevated levels downstream (2.067 mg/kg) compared to upstream (1.718 mg/kg). Chromium (Cr) levels showed no significant difference between locations. Gonadal tissue analysis revealed alarming contamination levels. In August, pelagic fish species exhibited higher lead (Pb) concentrations (0.2818 mg/kg) compared to benthic fish (0.3943 mg/kg). Similarly, cobalt (Co) levels were elevated in pelagic fish (0.02825 mg/kg) compared to benthic fish (0.03725 mg/kg). Nickel (Ni) concentrations were also higher in pelagic fish (0.04425 mg/kg) compared to benthic fish (0.04125 mg/kg). These results underscore the vulnerability of pelagic species to heavy metal accumulation. The study reveals a substantial impact of urban runoff on Ikpoba River heavy metal contamination. Elevated lead (Pb) and cobalt (Co) levels in downstream water, sediment, and fish gonads indicate significant pollution, likely originating from industrial activities. Pelagic fish species, in particular, are more susceptible to heavy metal accumulation. Urgent pollution control measures and ongoing monitoring are imperative to protect the river’s ecosystem and the health of communities depending on it. Further research should explore the long-term consequences and potential health risks associated with these heavy metal contaminant

Aquatic ecosystems are often subject to contamination by heavy metals due to human and natural activities. This study was conducted to determine the concentrations of heavy metals present in water, sediment and fish samples collected from Ikpoba River, Benin City, Nigeria. Samples were collected over from June to August 2023 and analysed using standard methods. The findings showed that while Cd and Pb were not detected in the water, Ni and Cr exceeded permissible limits. However, the concentrations of Co were within limits. Sediment samples had comparatively low heavy metal content. Benthic fish were found to have higher concentrations of heavy metals than pelagic fish. However, the concentrations of these metals in the samples were below the recommended limits for heavy metals in food. Therefore, it was concluded that the fish in the study area are safe for consumption but the water is not. Hence, routine surveillance and implementation of measures to protect water quality such as prevention of waste discharge are recommended