Impact of Urban Runoff on Benthic and Pelagic Fish Fauna in Ikpoba River: Metals Levels in Gonads

Abstract

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. The  concentrations of heavy metals (Cr, Co, Cd, Ni, Pb) in these samples were analyzed using an Atomic Absorption Spectrophotometer. Histopathological examinations of fish gonad tissues were also conducted. Downstream water samples in August exhibited significantly  elevated lead (Pb) levels (0.037 mg/L) and cobalt (Co) concentrations (0.02 mg/L) compared to upstream levels. Sediment analysis  revealed marked downstream contamination, with higher lead (Pb) levels (5.208 mg/kg) and cobalt (Co) concentrations (2.067 mg/kg) in  August. Gonadal tissue analysis showed alarming contamination levels, with pelagic fish species displaying higher lead (Pb) and cobalt  (Co) concentrations compared to benthic fish. These results highlight the vulnerability of pelagic species to heavy metal accumulation  and indicate substantial pollution from industrial sources in the Ikpoba River. Urgent pollution control measures and ongoing monitoring  are essential to safeguard the river's ecosystem and community health. Further research is recommended to explore the  long-term consequences and potential health risks associated with heavy metal contaminants in the river.