Levels of heavy metals in pelagic and benthic fish species in river Nun at Amassoma, Bayelsa State, Nigeri

The heavy metals content in three fish species from River nun Amassoma axis was investigated. This was done in order to gauge the concentration of heavy metals in fish tissues and to estimate the safety of consuming these fish species on human health. Three species (pelagic and benthic fishes) were collected from local fishermen at the landing jetty and analyzed for heavy metals in the soft tissues using standard procedures. The heavy metals investigated are Cadmium (Cd), Nickel (Ni), Lead (Pb) and Chromium (Cr). Result indicates that Cd>Ni>Pb>Cr in the fish samples analyzed while Chrysichthys auratus showed the greatest abundant characteristics of Cr, Pb, Ni, Cd. There was no significant difference (P>0.05) in concentrations of Cr and Ni for all fish species. However, the results showed that there is a significant difference (P<0.05) in Pb concentration between Chrysichthys auratus, Chrysichthys aluuensis and Petrocephalus bane bane. Cd concentration in the fish species reveal that there is a significant difference (P<0.05) between Chrysichthys auratus and Petrocephalus bane bane but no significant difference (P>0.05) between Chrysichthys auratus and Chrysichthys aluuensis and between Chrysichthys aluuensis and Petrocephalus bane bane Heavy metal in the fish species showed that Chrysichthys auratus>Chrysichthys aluuensis>Petrocephalus bane bane. All metal characteristics were lower than the suggested WHO permissible limit. Benthic fish species have a greater heavy metal concentration than the pelagic fishes. Based on the observation from this study, the continuous and sustained consumption of Chrysichthys auratus and indeed benthic fish species possess a higher risk to health, while Cd poisoning in fish is most culpable of pollution in River Nun at Amassoma. axis.