Seasonal variation in polychlorinated biphenyl and bisphenol a residues in Oreochromis niloticus and Hepsetus odoe from Eleyele Lake, Oyo State, Nigeria

Abstract

Fish occupy the top level of the food web in aquatic ecosystems and they are amplifiers of toxic substances present at lower trophic levels. Rapid uptake of pollutant by fish poses a potential threat to human consumers of fish due to bio-magnifications along the food chain. Polychlorinated Biphenyls (PCBs) and Bisphenol A (BPA) are chemicals of global concern, due to their persistence in the environment. These chemicals can be bio-accumulated by fish via the food chain. Therefore, this study was carried out to determine the seasonal variation of PCBs and BPA in selected fish muscles from Eleyele Lake. O. niloticus and H. odoe were procured from the fishermen at the shore of the lake. Samples were wrapped with aluminum foil, labeled, placed in a cooler containing ice, and transported to the laboratory. Fish muscles were removed; extraction and clean-up were carried out using standard procedures. H. odoe had the highest mean concentration of PCBs (81.63 ± 18.96ng/g), followed by O. niloticus (16.95 ± 8.18ng/g) and this was observed for the two species during the dry season. The mean concentration of Bisphenol A in O. niloticus during the wet season was 4.45 ± 1.08ng/g while, in H. odoe, it was 0.93 ± 0.03ng/g. the concentration of BPA and PCBs was higher than the recommended standard value. Therefore, it could affect human health.