Background: Ologe Lagoon is an important water body that receives effluents from neighboring industries. These effluents may increase the levels of anthropogenic contaminants in the lagoon, thereby creating stressors for aquatic organisms.
Objectives: To assess the occurrence of polycyclic aromatic hydrocarbons (PAHs) in Ologe Lagoon, along with the histopathological, biochemical and genotoxic effects of the most prevalent PAH compound.
Methods: An initial field study was performed to determine the concentrations of PAHs in Ologe Lagoon, followed by a chronic toxicity test to assess the effects of the most prevalent PAH compound in a fish model (Clarias gariepinus).
Results: High molecular weight PAHs were more predominant than low molecular weight PAHs in the lagoon, with B[b]F being the most predominant. The formation of micronuclei and binuclei was induced by a 10-fold increase over the present environmental concentration of B[b]F in Ologe Lagoon. Histopathological studies showed that epithelial necrosis, fused lamellae, shortened lamellae, and desquamation were the major histological anomalies induced by ERCs of B[b]F. Results from the biochemical assay indicated that ERCs of B[b] F increased aspartate aminotransferase and alanine transaminase levels in fish. Glutathione-S-transferase, superoxide dismutase and catalase were inhibited in the exposed fish, whereas malondialdehyde was significantly increased.
Conclusions: Concentrations of fluoranthene, pyrene, benzo[a]anthracene, and benzo[a] pyrene in the surface water of Ologe Lagoon were above the Canadian Council of Ministers of the Environment's (CCME) safe limits, suggesting that the water may not be safe for domestic uses, and the present concentration of B[b]F in Ologe Lagoon may be chronically toxic to aquatic organisms, in terms of oxidative stress and hepatotoxicity.
Competing interests: The authors declare no competing financial interests.
Keywords: benzo[b]fluoranthene; biomarkers; environmental relevance; genotoxicity; hepatotoxicity; oxidative stress; polycyclic aromatic hydrocarbons.