Heavy metal concentrations in some freshwater fishes of Niger State, Nigeria

Abstract

Concentrations of the heavy metals Lead, Copper, Zinc, Cadmium and Nickel were determined in the flesh, intestine and gills of nine most common freshwater fishes found in Niger State of Nigeria. Samples of fishes were collected from Minna Central fish market over a period of five days. Generally, fish species accumulate metals in the order Zinc˃Copper˃ lead˃Nickel˃Cadmium, except in Clarateslaticapae and Tilapia niloticus where the order was Copper˃ Zinc˃ lead ˃Nickel˃ Cadmium. Metal accumulation in fish samples was greater in the internal organs than in the flesh, except for Copper. For zinc and Nickel, the order was intestine˃ gills˃ flesh while Copper the order was intestine flesh gills. Levels of the metals in fish samples were generally below the WHO and FAO maximum permissive limits of Lead (1.5𝜇g/g), Copper (120𝜇g/g), Zinc (150𝜇g/g), Cadmium (0,5𝜇g/g) and Nickel (0.4𝜇g/g) and hence pose no consumption risk.