Assessment of Heavy Metal Contamination in Water and Sediment from Odo Oba River Tributaries in Ogbomoso, Nigeria

Abstract

Heavy metal pollution in aquatic environments poses significant threats to the environment and human health. This study assessed heavy metal pollution in water and sediment samples from three sites (A, B, and C) along the Oba tributaries, examining regional and seasonal variations. Water analysis revealed Fe levels exceeding the Nigerian Standard for Drinking Water Quality (0.3 mg/kg), peaking at Site B (8.06 ± 0.22 mg/kg). Cu and Zn levels remained acceptable, while Cr was detected at Sites A and C at concentrations < 0.05 mg/kg, whereas Cd and Pb levels were undetectable. Rainy season samples had significantly greater Fe, Cu, and Zn contents, whereas Cr was only found in the dry season. During the rainy season, Fe concentrations in sediments at Sites B and C surpassed the WHO's 5 mg/kg limit, reaching up to 20.00 ± 1.79 mg/kg. Cu, Zn, and Cr levels were within legal limits but varied spatially. Pb was detected at Sites B and C, with the highest concentration at Site C (0.08 ± 0.02 mg/kg), while Cd was not detected. This study therefore necessitates remediation initiatives and monitoring of Oba tributaries.