Development and investigation of a multiparameter microbial toxicity test using the bacterium Salmonella typhimurium

Abstract

Experimental procedures were developed to test the effects of various pure compounds and papermill wastewater samples on the growth rate, intracellular ATP concentration and oxygen-utilization rate of the bacterium, Salmonella typhimurium TA98. Responses of the bacterium to increasing concentrations of three specific inhibitors, cyanide, 2,4-dinitrophenol, and chloramphenicol corresponded well with the predicted results. Comparison of microbial responses to specific inhibitors and mechanistically uncharacterized compounds suggested general inhibitory mechanisms for the latter chemicals. Correlations between measured relative toxicities of a homologous series of chlorinated phenols with the log octanol/water partition coefficients of those compounds indicated a strong relationship between toxicity and hydrophobicity. Correlations with published toxicity data for the pure compounds showed generally good agreement between the S. typhimurium test and other aquatic toxicity tests. Intracellular ATP concentration was the most sensitive indicator of toxicity in tests involving papermill wastewater samples.