Using Bioluminescent Bacteria to Detect Water Contaminants

Conventional chemical analyses typically have a specificity that makes it difficult to apply them efficiently in the assay of a broad range of water contaminants. An economical bioassay method for determining the toxicity of aquatic contaminants in developing countries should help improve public health worldwide. This research explored the effect of six contaminants- CuSO4, ZnSO4, NaNO3, HgCl2, Atrazine, and Permetherin, on the bioluminescence of the bacterium Vibrio fischeri. A decrease in V. fischeri bioluminescence was correlated to the presence of contamination. Bacteria were cultured in both liquid flasks and on agar plates, and contaminants were added according to EPA Maximum Contaminant Level values. Bioluminescence was determined by photographing cultures at a 30-second exposure in a lightproof box with a digital camera connected to a PC. The mean light intensity of each image was determined with Image J Batch Measure Macro. The effect of all contaminants on bioluminescence could be detected within 150 min. of their introduction