Acute Toxicity of Aqueous Methanol on Juvenile Guinean Tilapia (Tilapia guineensis)

This study was conducted to evaluate the acute toxicity of Juvenile Tilapia guineensis exposed to aqueous methanol (Analytical grade). The fishes were obtained from the Nigeria Institute for Oceanography and Marine Research (NIOMR), Buguma, Rivers State, Nigeria. The fishes were acclimated to an aquarium for 14 days. A range-finding test of the toxicity of aqueous analytical methanol was conducted. Based on the preliminary results, a definitive test was conducted at 0ml/l as control (0ml/l), 2.5 ml/l, 5.0ml/l, 10.0ml/l, 15.0ml/l, 20.0ml/l and 25.0ml/l respectively. From the data, the concentration-response curves for fish mortality, the LC50s, and the 95 percent confidence intervals for test organisms at 24hr, 48hr, 72hr, and 96hr in a static system were derived following the standard procedure. The mortality rates increased significantly (p<0.05) with an increase in the concentration of the test chemical. The LC50 values at 24, 48, 72 and 96 hours recorded were 30.361 ml/l, 16.585 ml/l, 7.369 ml/l, and 3.750 ml/l respectively for the aqueous analytical methanol. The LC50 values showed that the test chemical is toxic to the juvenile T. guineensis. Therefore, proper handling and discharge of this chemical into the aquatic environment should be minimized to avoid possible toxic effects on the aquatic life therein.