Аннотация:The paper summarizes the results of studies on the application of the model system oflipid peroxidation in vitro for solving the following environmental problems: Assessmentof the quality and biological usefulness of the natural aquatic environment; Detoxificationof black liquor solutions for pulp and paper industry with hydrogen peroxide; Selection ofthe most sensitive and express model for bioindication of biologically active drugs in ultra–low doses; Application of biotesting methods for toxicological control of transformation products of surfactants as a result of the combined action of photoozonation processes and further biodegradation.