摘要：This study was performed to determine acute toxicity of a mixture of five water-borne metals (iron, zinc, lead, nickel and manganese) to fresh water fish species Cirrhina mrigala L. We performed acute toxicity assays to determined LC50 (concentration at which 50% fish die) and LC95 (concentration at which 95% fish die) of the metals mixture after 96 hours of exposure to one-month old fish specimens. All the assays were performed in glass aquaria of 100 liters volume. We found significant difference between LC50 (26.84 mg L-1) and LC95 (70.42 mg L-1) of metals mixture for C. mrigala. The amount of total sodium, potassium and calcium increased with increasing concentration of the metals mixture, as did total ammonia in the test medium however, concentration of magnesium decreased significantly. We also observed increased use of oxygen by the fish under stress of heavy metals mixture, and in turn accelerated carbon dioxide release into the water that increases water pollution. We conclude that the tested metals mixture is highly toxic to C. mrigala. Further work is recommended to unearth molecular basis of, and synergistic effects of the metals toxicity to fish fauna.
