TOXICOLOGICAL EVALUATIONS OF TREATED COSMETIC EFFLUENT ON CLARIAS GARIEPINUS (THE AFRICAN SHARPTOOTH CATFISH)

Abstract

The preponderance of industrial activities has led to the discharge of often untreated effluents into
the aquatic environment. Some industries endeavour to carry out some form of treatment on their
effluent before discharge into the environment; however, there is need to determine the efficiency
of such treatment by evaluating potential biological effects in aquatic organisms. In this study, we
investigated the physico-chemical parameters of a treated cosmetic effluent as well as the
biochemical and histological effects of sublethal concentrations of the effluent in Clarias
gariepinus (The African sharptooth catfish) over a period of 28 days. Some physico-chemical
parameters including zinc and lead were higher than the Federal Ministry of Environment set
limits while others such as phthalate, triclosan and parabens were not detected. The median lethal
concentration of the effluent to C. gariepinus was 4.14 mL/L (0.41%). Significant changes
(p≤0.05) were observed in the levels of reduced glutathione and malondialdehyde in the liver of C.
gariepinus exposed to sublethal concentrations of the treated effluent compared to control after 14
and 28 days of exposure. Histological alterations observed in C. gariepinus exposed to sublethal
concentrations of the treated effluent were shortening/blunting of secondary lamellae in the gills
and hepatic central veins infiltrated with red blood cells in the liver. The results show that longterm exposure to sublethal concentrations of the treated cosmetic effluents may cause deleterious
effects to animals inhabiting recipient freshwater ecosystems. Further studies to explore other
potential biological effects of treated cosmetic effluents are recommended in order to provide
holistic and evidence-based information to relevant stakeholders and environmental regulatory
agencies.