Method of detecting toxic compositions in water by monitoring the metabolism of selected living cells as microorganisms.

The method is based upon the time detection of some biochemical parameters of microbial metabolism such as acidification of the environment, production of carbon dioxide, increase of turbidity, and decrease of dissolved oxygen. Such parameters are detected in a thermostated cell containing particular microorganisms and a composition having a toxic effect. The detected parameters have a different course with respect to those detected in a thermostated control cell where the toxic composition is left out. The decrease of the values of the normal microbial metabolism is proportional to the amount of toxic composition. Such a method can then be used to detect without the chemical analysis of the chassic methods any amount of a toxic composition in water. To this end microorganisms properly selected for their sensitivity to different toxic compositions are used.