Foreword
The toxicity test is one of the summary parameters recommended for the regulatory purpose. The existing toxicity test methods are based on LC50 (IS:6582 - 1971), which can not be used for regulatory purposes.

The Central Pollution Control Board has developed Toxicity Factor based toxicity measurement method. To adapt this method for regulatory purpose, it is necessary to evolve effluent standards based on Toxicity Factor based method. Accordingly, Central Pollution Control Board has undertaken studies in various categories of industries for evaluation of toxicity based standards. The report presents the findings and trends of toxicity among the studied category of industries and effectiveness of existing effluent treatment technique in reduction of toxicity. The Central Pollution Control Board along with six other Research & Development Laboratories and Pollution Control Laboratories were associated with the study. The cooperation extended by various industries to undertake the study is duly acknowledged.

We hope, this document will provide baseline information in evolving the Minimum National Standards (MINAS) for Toxicity. The information may also be valuable for Pollution Control Boards in adopting summary parameters to regulate the effluent discharges.