Many industries in India discharge their effluents directly or indirectly into inland water bodies leading to the nearby rivers. It is found that almost all industries are violating rule for discharging effluents and polluting nearby fresh water bodies and agricultural land. Present study was undertaken to determine toxicity of a paper mill effluent to fresh water fish Puntius stigma for 24 to 96 hours using renewal bioassay method. The estimate LC50 values, series of concentrations [% dilutions] were prepared for 24, 48, 72 and 96 hrs and expected mortalities were found at 40, 35, 30 and 25% concentrations respectively of the effluent.
Gross effects like erratic swimming, jerky movement, and rapid opercular movements leaping out of water and excess mucous secretion were observed during experiments. Therefore, adequate steps have to be taken towards compliance of all environmental quality standards for betterment of the environment and reduce health impact.
Key words: Paper mill effluent, Toxicity, Behavior, Puntius stigma.