ACUTE TOXICITY AND BEHAVIOURAL CHANGES IN FRESHWATER FISH MYSTUS VITTATUS (BLOCH) EXPOSED TO CHROMIUM (Ⅵ) OXIDE

摘要

The acute toxicity tests (24, 48, 72 and 96hr) were conducted using static and renewable bioassay method to determine the lethal toxicity (LC_(50)) of a heavy metal compound chromium (Ⅵ) oxide to the freshwater fish, Mystus villaius (Bloch) and to study its behavioural response during toxicity test. The safe level concentration was also determined. The dose and dose-time dependent increases in mortality rate were observed in the fish in response to chromium (Ⅵ) oxide. Behavioural parameters under investigations showed prominent changes as erratic swimming activity, increase in opercular movement, jerk and violent reaction, loss of equilibrium, and aggressiveness in fish exposed to lethal concentration of chromium (Ⅵ) oxide. The prominent features of death were respiratory distress, paralysis and loss of equilibrium