Heavy metal content in fish and water from River Niger at Agenebode, Edo State, Nigeria

Abstract

The concentrations of Lead (Pb), Copper (Cu), Cadmium (Cd) and Zinc (Zn) in fish and water from River Niger at Agenebode, Nigeria were determined by atomic absorption spectrometric technique. The mean concentrations of heavy metals in water ranged from 0.00742 mg/L for Pb to 0.239 mg/L for Zn. The summary statistics for heavy metals in fish showed that the mean concentrations of metals ranged from 0.0291 mg/kg for Pb to 69.14 mg/kg for Zn, while the mean concentrations of metals in individual fish species ranged from below detection/quantification limit (BQL) for Pb in Barbus occidentalis and Chrysichthys nigrodigitatus to 128.87 mg/kg for Zn in Hemichromis fasciatus. The bioaccumulation quotient (BQ) values for metals in fish ranged from BQL for Pb in B. occidentalis and C. nigrodigitatus to 539.21 for Zn in H. fasciatus, while the condition factor for the fish species ranged from 0.32 in Clarias gariepinus to 2.07 in Oreochromis niloticus. The maximum acceptable risk (MAR) values for heavy metals in fish ranged from BQL for Pb in B. occidentalis and C. nigrodigitatus to 6.38 for Cu in H. fasciatus; while the Hazard Quotient (HQ) values for heavy metals in water ranged from 0.05 for Zn to 0.43 for Cd. In fish, the HQ values ranged from BQL for Pb in B. occidentalis and C. nigrodigitatus to 10.74 for Zn in H. fasciatus. The National Environmental Standard and Regulation Enforcement Agency (NESREA) were enjoined to ensure that the environmental safety of our inland water bodies is sustained in order to mitigate negative impacts on human health.

Key words: Heavy metals, fish, River Niger, maximum acceptable risk, hazard quotient.