Abstract: The invention relates to a method and device for detecting the toxic and mutagenic effect of chemicals and mixtures of substances using immobilized luminescent bacteria or microorganisms that have been rendered bioluminescent by the transfer of adequate vector plasmids, which are provided with an optoelectronic component for photometry in such a way that a biosensor is formed. Since the detection of biological effects can take place during a long period of time, the invention makes it possible to carry out surveillance tasks in the environment and to conduct process controls in agriculture and industry.