ABSTRACT
This research was to assess and compare the concentrations of selected heavy metals in fish and sediment samples collected from Ikpoba River, Benin City, Nigeria, during the months of June and November, 2023. The accumulation of heavy metals in fish is a significant concern due to their tendency to accumulate both the essential and non-essential heavy metals in their muscles, gills and liver. Heavy metals correlations were determined and results from Atomic Absorption Spectrophotometer (AAS) analysis showed the presence of all ten selected heavy metals (Iron (Fe), Chromium (Cr), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Arsenic (As), Cobalt (Co), Nickel (Ni), and Cadmium (Cd)) in both the fish species Coptodon zilli and sediment samples. However, sediment samples showed higher concentrations of heavy metals compared to the fish. Sediments exhibited higher levels of iron (Fe) and nickel (Ni) in June, and lower levels of cadmium (Cd) and lead (Pb) in November. The order of heavy metal concentration in sediments was as follows: June: Fe > Ni > Zn >Cr > Co >Mn>Pb> As > Cu > Cd; November: Fe > Ni > Cr > Co > Zn > Cd > As > Mg > Cu >Pb. Analysis of heavy metals in gill, liver, and muscle revealed that iron (Fe) had the highest concentration of heavy metals in the muscle, gill, and liver for both months, while copper (Cu) had the lowest concentration in these tissues, except for muscle, June and liver, November. The concentrations of selected heavy metals exceeded the maximum limits set by the World Health Organization (WHO), Food and Agricultural Organization (FAO) and National Environmental Standard and Regulation Enforcement Agency (NESREA) in both sediment and fish samples during June and November, except for Zinc (Zn) and Copper (Cu) in fish samples. This may result to chronic illness and cause potential damages to the population. Therefore, precautionary measures and continuous monitoring of Ikpoba River is necessary.
