The use of a multiparameter bacterial aquatic toxicity test

Abstract

A multiparameter microbial toxicity test using Spirochaeta aurantia was used in this investigation. The multiparameter assay procedure consisted of simultaneous measurements of specific growth rate, intracellular ATP concentrations and oxygen utilization. After calibrating the test with compounds of known toxic mechanisms, the assay was then used to investigate the relative toxicity and inhibitory mechanisms of a series of chlorinated phenols, chlorinated ethanes, metals and complex wastewaters. Relative toxicities were based on bacterial growth on specific growth rate in the presence of different concentrations of tester chemicals. Toxicity generally increased with degree of chlorination for the halogenated- compounds. However, better correlations were observed between compound toxicity and log octanol/water partition coefficients, suggesting that a strong relationship exists between hydrophobicity and chemical toxicity for these compounds. Toxicity data obtained from other bioassays including Mictrotox, Daphnia magna and various fish species correlated well the results of the S. aurantia test.