Eco-Histopathology of Nile Tilapia (Oreochromis niloticus) and African Catfish (Clarias gariepinus) from Industrially Contaminated Locations of Ologe Lagoon, South-western, Nigeria

Abstract

A study was carried out to assess the physico-chemical, heavy-metals parameter and Histopathology of adult fish specimen of Oreochromis niloticus and Clarias gariepinus collected from effluents sources of Ologe lagoon. The aim of the study is to assess the impact of industrial effluents on the lagoon, and on the health of resident fish fauna. 5 sample stations were marked out. Water samples were collected in triplicates; once every two months from each sample station. Effluent samples from the three point sources were also analyzed. Mean values for physico-chemical parameters, heavy-metals and three other effluent sources monitored ranges are pH, 6.17±0.42-10.25±1.18, DO, 1.18±0.50-6.13±1.03 mg/l, TDS, 86.6±19.17-621.97±16.22 mg/l, hardness, ND–58.03±0.90 mg/l, alkalinity, 22.06±8.08-352.37±14.58 mg/l, Cl-1, 31.09±18.16-268.98±31.41 mg/l, acidity, ND-73.73±13.00 mg/l, Zn, 0.07±0.01-0.65±0.18 mg/l, Fe, ND-1.40±0.50 mg/l, Cu, 0.001±0.001-0.53±0.36 mg/l, Cd, ND-0.07±0.02 mg/l, and Pb, ND-10.15±21.83 mg/l. Several live lesions have been observed in the study as tissue bio-makers consistent with the exposure of fish to effluent. These include pigmented macrophage aggregation, hepatocytes vacoulation, multi foci coagulative necrosis and liver fatty degeneration. The preponderance of these lesions in fish from contaminated waters bordering urban locations similar to our test location has been firmly established and described by other researchers. Therefore, the extent of deformities and cell injuries is as a result of toxicant actions of the industrial effluents.