The V. fischeri assay requires an isotonic diluent prepared with 2% sodium chloride. An addition of 3 mg/L sodium thiosulfate is necessary to remove chlorine added in the drinking water process. Matrix control tests showed that sodium thiosulfate did not result in significant positive responses. Results indicate that sodium thiosulfate has no statistically significant effect on copper and cyanide, and a synergistic effect on malathion toxicity. Dose-response curves showing the effect of sodium thiosulfate on toxicity of each compound are presented.
Effect of sodium thiosulfate on toxicity of copper, cyanide, and malathion to vibrio fischeri using the toxControl online toxicity monitor
The U.S. Environmental Protection Agency is conducting research to develop online toxicity monitors (OTMs) for use in water quality early warning systems. A major element of this effort is determining the applicability of different OTMs and their responses to various toxic substances. One aspect of this research is the potential application of OTMs in drinking water distribution early warning systems. In order to accomplish this, a dechlorination agent must be used. This raises the question regarding interaction between the dechlorination agent and potential contaminants resulting in synergistic or antagonistic effects. Here we present work performed using the estuarine luminescent bacteria Vibrio fischeri in a Microlan ToxControl system and Copper, Cyanide, and Malathion.