ASSESSMENT OF HEAVY METALS IN SOME SELECTED FISH SPECIES FROM RIVER NIGER, ILLUSHI, EDO STATE, NIGERIA

Abstract

This study was conducted in River Niger at Illushi, Edo State, Nigeria to determine the concentration of Arsenic,
Cadmium, Iron, Manganese and Nickel in Bagrus bayad macropterus, Clarias gariepinus, Malapterurus
electricus, Parachanna obscura, Synodontis batensoda and Synodontis budgetti. The sampling was done
monthly from April to November, 2017. Heavy metal concentrations were determined using Atomic Absorption
Spectrophotometer (AAS Bulk scientific VGP 210 model) according to the standard method. Synodontis budgetti
accumulated the highest level of heavy metals (32.13%), followed by Bagrus bayad macropterus (19.72%),
Clarias gariepinus (17.80%), Synodontis batensoda (10.68%), Parachanna obscura (10.61%) and the least was
Malapterurus electricus (9.02%). The accumulation of heavy metals in the fish species was in the order Fe ˃ Ni
˃ Mn ˃ Cd ˃ As (B. bayad macropterus), Fe ˃ Mn ˃ Ni ˃ Cd ˃ As (C. gariepinus and S. budgetti), Fe ˃ Ni ˃
Mn ˃ As ˃ Cd (M. electricus, P. obscura and S. batensoda). Clarias gariepinus and Synodontis budgetti had
Mn exceeding the limit, other fishes had concentration below permissible limit. The level of Ni, Cd and As in all
the fishes were below the permissible limit, while the level of Fe in all the fishes exceeded the limit.