Sensitivity and significance of luminescent bacteria in chronic toxicity testing based on growth and bioluminescence.

This study explored the use of luminescent bacteria (Vibrio fischeri) for chronic aquatic toxicity tests. The evaluated inhibition of growth to Cu2+, Cr6+, Zn2+, Hg2+, Cd2+, Pb2+, cetyl-trimethylammonium bromide, 3,4-dichloroaniline, acetone, dimethylsulfoxide, ethanol, nitrobenzene, methanol, and 3,5-dichlorophenol was compared with results from another investigation, where the inhibition was determined by bioluminescence. Growth inhibition was found to indicate more reliably the presence of substances with chronic toxic properties than the loss of bioluminescence. But growth responded weaker to the majority of the analyzed toxicants than bioluminescence. This must be connected with the test parameters and the experimental conditions. But among growth experiments with freshwater bacteria species the sensitivity of the growth inhibition assay with V. fischeri is competitive when a poor medium is employed.