Quantal Response and Histopathological Effects of Sub-lethal Concentrations of a Selected Oilfield Chemical on African Catfish (Clarias gariepinus)

Abstract

The behavioural and histological effects of sublethal concentrations (0.0 ml/L, 12.8 ml/L, 25.59 ml/L, 38.39 ml/L, 51.19 ml/L, and 63.99 ml/L) of Xylene were evaluated in African Catfish (Clarias gariepinus) after 28 days of exposure. Physico-chemical parameters such as temperature, conductivity, hydrogen ion concentration (pH), total hardness, total dissolved solids, dissolved oxygen, total alkalinity, ammonia, and nitrate levels in the experiment were monitored using the standard method. Significant variations were observed in the different units except for the controlled unit. Behavioural changes were observed closely during the sublethal toxicity test using standard procedures. The bioassay experiments were repeated three times and the renewable test method was used. concentrations showed histopathological alterations in the gills and liver. Severely deformations were observed at 12.80ml/l, 38.39ml/l), 51.19ml/l, and 63.99ml/l. No form of abnormalities was observed in the fish gill and liver in the controlled unit. Progressive hyperventilation, faster operculum and tail beat movement, erratic movement, gulping of air, and spiralling. jumping, display of vigorous jerky movement suffocation, and loss of reflex were observed in C. gariepinus exposed to higher sublethal concentrations of Xylene. There was a significant dose-dependent variation in parameters in the experiment. In conclusion, xylene caused an alteration in the histopathological parameters and the behaviour of C. garienpinus. Therefore, we recommend the need for realistic regulatory measures and proper monitoring and sensitization on use to stakeholders.