Heavy Metal Concentration in Water, Sediment and Fish Species in the Bontanga Reservoir, Ghana

Abstract

This study assessed heavy metals levels in four selected fish species, water and sediment from the Bontanga Reservoir. Samples were collected on weekly basis and analysed using standards methods. Physico-chemical properties of the water were all within World Health Organization (WHO) limits except for turbidity. The study recorded cadmium concentration in the water sample the ranged from 0 to 0.01 mg L-1 that shows some were above WHO stipulated limits for potability. Heavy metal concentration in water was in the order Fe>Cr>Mn>Cu>Cd>Zn>Pb and in sediments Fe>Mn>Cr>Cu>Zn>Cd>Pb which showed that iron was more abundant. Cd and Cr were above WHO limits for potability which make the water unsafe for drinking without treatment. Heavy metals in the sediment were within Food and Agricultural Organisation (FAO)/WHO limit. Concentrations of heavy metals in the various species were within the recommended limit for fish and fish products. Hence, these metals have no immediate health threat on the consumers of fish and fish products from Bontanga Reservoir but will likely have adverse effects in the prolong consumption of the fish species since heavy metals accumulate. Periodic monitoring of heavy metals in Bontanga reservoir is recommended since the reservoir serves as a source of fish and water for all-year-round irrigational farming.