Abstract

TOXICOLOGICAL ASSESSMENT OF SOME INDUSTRIAL EFFLUENTS ON CLARIAS GARIEPINUS

Leritshimwa Amagon*, Stephen Samuel Gyang and Kennedy Iliya Amagon

Abstract

Industrial effluent discharges are a worrisome phenomenon due to their impact on aquatic life, with direct effects on humans who consume fish and other aquatic life. This study aimed at assessing the acute and chronic toxicity of discharged industrial effluents on fish. 400 fingerlings of the African catfish (Clarias gariepinus) were exposed to different effluents (in tanks) from factories that manufacture paint (A), household products (B), feed, food and oil (C), carbonated drinks (D) at concentrations of 25, 50, 75 and 100% volume-in-volume respectively. The effluents were analyzed for trace metal concentration and physicochemical parameters. Acute toxicity testing involved exposing 10 fish per tank for each effluent at the different concentrations for 96 hours. Acute (LC50) and sub-acute toxicity tests were conducted by exposing a different set of fish to different effluent concentrations of each sample for 28 days. The surviving fish were sacrificed, the liver and kidney collected and processed for histopathological analysis. Lead, chromium and cadmium were detected in samples. Lethal bioassay showed 20% and 100% mortality occurring in effluent A and C after 96 hours and effluent B after 24 hours respectively (at 50, 75 and 100% effluent concentrations). Histopathological analysis showed loss of cellular architecture, with fat vacuoles, hepatocellular degeneration and necrosis observed. Effluents were found to cause toxicity in fish and are capable of causing serious health risks to both aquatic and human lives exposed to these toxicants.

Keywords: Acute toxicity, Clarias gariepinus, Industrial effluents, Mortality.