The objective of the project is to demonstrate biological early warning systems for monitoring industrial waste water with mixtures of pollutants. Four industrial demonstration sites are to be selected by the Netherlands Institute for Water Management and Waste Water Treatment, the industries belonging to the petrochemical, pesticide manufacturing, tank cleaning, and synthetic fiber sectors. At each industrial site, a fish biomonitoring system will be installed and supplied with treated industrial waste water effluent. These monitors should enable industry to take immediate remedial action, should the toxicity of its waste effluents increase. The monitor performance will be evaluated on the basis of their reliability.