Acute Toxicity of a Glass Manufacturing Effluent in Midwestern Nigeria on the African Catfish (Clarias gariepinus)

Untreated and improperly treated industrial effluents endanger the aquatic fauna of the receiving water bodies, making the appropriate monitoring of the effluent discharges from industrial facilities of utmost importance. The potential ecological impact of the effluent from a glass manufacturing facility was investigated using the African catfish (Clarias gariepinus). Renewable static bioassay with continuous aeration was used to evaluate the acute toxicity of the different dilution percentiles of the wastewater for 96 h under laboratory conditions. The physicochemical and metal assays of the industrial effluent were carried out using standard methods. Significant concentration-dependent increase (p < 0.05) in mortality rates was established. Respiratory disturbance, erratic swimming, loss of equilibrium, lethargies and sudden death were observed in the exposed fish and these varied greatly with increase in concentration of the industrial effluent. The mortality rate of 46.25% was obtained with the 96-h LC50 of 13.80 mg/L using the Probit analysis statistical tool. Several physicochemical parameters (pH, dissolved oxygen, turbidity, electrical conductivity, total suspended solids, nitrates, and phosphates) were non-compliant with the standards set by the National Environmental Standards and Regulations Enforcement Agency (NESREA). The assayed metals were within the set limits, except for Mg, Cu, Fe, and Zn. The non-conformity of the industrial effluent discharge to established standards may pose threat to aquatic faunas present in the receiving water bodies.