ACUTE TOXICITY OF CALCIUM CARBIDE WASTE TO SILVER CATFISH (Chrysichthys nigrodigitatus) JUVENILES

Résumé

The indiscriminate dumping and accumulation of spent carbide is a potential threat to the survival and good health of fish. Therefore, this study investigated the effect of spent carbide on selected organs (brain and gills) and survival of Chrysichthys nigrodigitatus. Fish were exposed to powdered carbide concentration of 0.0 mg/L, 0.018mg/L, 0.0033mg/L, 0.060mg/L and 0.105 mg/L under laboratory condition for 96 hours in a complete randomized design using three (3) replicates. The LC50 value of 0.018 mg/L was obtained using graphic and probit methods. Histological alterations in the brain of fish showed spongiosis, congestion of blood capillaries and vacuolation. The gills recorded structural changes such as stunted primary gill lamellae, congestion of gill capillaries and erosion of gill lamellae. Hence, there is a need to protect the fish and consumers by finding alternative use of carbide waste or safer means of its disposal to avoid contamination of ground water and aquatic life.