The acute toxicity of tobacco (Nicotiana tobaccum) leaf dust, on the juvenile African catfish
(Clarias gariepinus) was assessed in a static renewal bioassay system for 96 hours. Five
graded concentrations of tobacco leaf dust were prepared as 25.00, 20.00, 15.00, 10.00, 05.00
mg/l and a control experiment (0.00mg/l). The 96hour LC50 value was 10.96mg/l, r2 value of
0.68 with 95% lower and upper confidence limit of 7.50 and 16.00 mg/L respectively. At varied
concentrations of tobacco leaf dust, the fish showed erratic swimming, secretion of mucus,
respiratory distress, and darkening of skin. Mortality was recorded in all concentration of
tobacco leaf dust tested.
