Toxic Effect of Brewery Effluent on Fingerlings of Clarias gariepinus

Background:The indiscriminate discharge of waste-water (effluent) as influenced by industrialization and development create significant pollution problems to normal flora and fauna of the ecosystem. Toxicity of brewery effluent remain unknown, particularly its implications on histopathology of fish under continous exposure. The study unravels the effects of brewery effluent on fingerlings of Clarias gariepinus under laboratory conditions.

Materials and Methods: Fingerlings of Clarias gariepinus (of mixed sex) (5.20×0.42g) were exposed to various concentrations of brewery effluent in five treatment (in duplicate) 15, 20, 25, 30, 35% and 0.00% for control The Toxicity and histopathology of the gills and liver of fish exposed were observed under laboratory conditions.

Result: Acute concentrations had adverse effects on mortality and oxygen consumption. The 96-h LC₅₀ of brewery effluent was 23.99ml/l with upper and lower confidence limits of 29.478ml/l and 18.324ml/l respectively. Symptoms of toxicity include restlessness, air gulping, loss of equilibrium, exhaustion and death. Exposure of the Clarias gariepinus fingerlings to various lethal concentrations of the brewery effluent were implicated in the histopathological examinations of gills which showed mutilations of gill filament, Oedema, fusion of central venous sinus, swelling, necrosis of various degrees and total lamellar hyperplasia. The liver showed evidence of necrosis and vacuolation of liver cells whereas control group showed both normal gill and liver section.

Conclusion. The indiscriminate or deliberate discharge of industrial effluent (brewery effluent) directly into the aquatic environment without any form of treatment is a common sight in many industrial cities of Nigeria today; therefore, creating awareness for environmental protection through sustainable production processes is of utmost significant.