Effect of Kerosene on the Respiratory Organ (Gill) of African Catfish (Clarias gariepinus)

Abstract

This study investigated the effect of kerosene on the respiratory organ (gill) of juvenile African catfish (Clarias gariepinus) under laboratory condition for 96hours. A total of hundred and twenty (120) juvenile C. gariepinus was used in six (6) different aquaria having duplicates i.e. ten (10) juveniles each were grouped into twelve (12) different test aquaria and held for 24, 48, 72 and 96 hours in six (6) different concentrations of kerosene (0, 0.4,0.8, 1.2, 1.6, 2.0ml/L). At the end of the test period, histopathological examination of the gills was conducted. The LC50 of kerosene in the water was noted to be 1.05ml/L. During the period of exposure of test fish to this toxicant, respiratory distress, aggression, weakness, erratic swimming, loss of balance, sluggish movement were common reactions of the test fish at the time of toxicant application before death. It was also observed that mortality was toxicant dependent (i.e. the higher the concentration of toxicant the higher the number of dead fish recorded). Histopathological examination of the gills exposed to kerosene showed lesions, degradation of filament, and necrosis with increasing concentration of kerosene, which in relation to previous studies indicates reduced dissolved oxygen level, resulting in respiratory challenge/difficulty. All the juveniles held in the control aquaria showed no histopathological degradation. Conclusively, this study has been able to reveal that exposing juvenile African catfish to even low concentrations of kerosene could lead to histopathological damage on the fish gill structure. Conclusively, a safe concentration was established using an application factor of 0.01 (for industrial chemicals and pesticides). We arrived at safe concentration level of 0.0105 ml/L. Thus, if the kerosene concentrations remain below 0.0105 ml/L, juveniles of C. gariepinus as well as other aquatic species will suffer no adverse effects.