Use of bacterial biosensors to interpret the toxicity and mixture toxicityof herbicides in freshwater

The dose response relationship between seven commonly used herbicides and f our luminescence-based bacterial biosensors was characterised. As herbicide concentration increased the light emitted by the test organism declined in a concentration dependent manner. These dose responses were used to compar e the predicted vs. observed response of a biosensor in the presence of mul tiple contaminants. For the majority of herbicide interactions, the relatio nship was not additive but primarily antagonistic and sometimes synergistic . These biosensors provide a sensitive test and are able to screen a large volume and wide range of samples with relative rapidity and case of interpr etation. In this study biosensor technology has been successfully applied t o interpret the interactive effects of herbicides in freshwater environment s. (C) 2001 Elsevier Science Ltd. All rights reserved.