Abdullahi, U.A. and Ibrahim, S

Keywords: Toxicity; Histopathology; Textile and Dyeing; Kano; Catfish(Clarias gariepinus)

Abstract

Compromise the processing standard during dyeing and textile activities coupled with incomplete sewage treatment system lead to indiscriminate discharge of large amount of dyestuff into water bodies mostly used for irrigation and fishing. These wastes are potentially toxic, mutagenic and some are even carcinogenic. In this research, acute toxicity test as well as histopathological studies using African catfish (Clarias gariepinus) juveniles exposed to different concentrations of textile and dyeing effluents in Kano, Nigeria. The results of acute toxicity test revealed an increase in mortality of the fish with increase in concentrations of the treatment after 72hrs. of exposure, while no such mortality were observed in control group. The lethal concentrations causing 50% mortality (LC50) were determined as 14.8%, 22.4% and 14.45% for ATM, KofarNaisa and Kofar Mata dyeing points respectively, while, the safe concentrations were 1.48%, 2.24% and 1.445% for the above three sites respectively. Histopathological test showed various degree of effects including distortion in skins and muscles as well as mutilations of gills in exposed groups with none such effects in control group. Among these are slight to severe degeneration of skin tissues in 25% and 75% concentrations of textile effluents. In addition, there are localized lacerations in different concentrations of dyeing effluents. The observed histopathological effects on gills ranges from slight mutilation of secondary lamella of the gills rakers to severely injured secondary lamella for textile effluents, the peak being complete deterioration of central core hyaline cartilage in 75% and 100% dyeing effluents. It was concluded that, there were histopathological anomalies that serves as bioindicators of environmental pollution. The study therefore, provides warning of potential adverse environmental effects of textile and dyeing effluents on the receiving aquatic ecosystem in Kano metropolis.