Comparison of three rapid toxicity test procedures: Microtox,® polytox,® and activated sludge respiration inhibition

Abstract

Abstract Methods for measuring respiratory activity can detect adverse effects on heterotrophic microorganisms. These methods are useful tools for assessing the impact of chemicals on biological wastewater treatment processes. They are also well suited for evaluating the treatability potential of individual wastes. However, varying results are often reported when using municipal or industrial activated sludge substrate in toxicity assessments. The lack of reproducibility of these tests has also greatly limited efforts to measure the effectiveness of treatment plants in removing toxic contaminants. The toxicity of waste‐waters and chemicals to biological treatment systems can be determined in 30 min with the new Polytox® toxicity procedure. The Polytox® kit utilizes a specialized blend of bacterial cultures. The objective of this paper is to evaluate the relative sensitivity of the new Polytox® toxicity procedure with two accepted microbial assay procedures; namely, the Microtox® bioluminescence assay and the Organization for Economic Cooperation and Development's Activated Sludge Respiration Inhibition test. This paper compares toxicity values for selected inorganic and organic chemicals as determined in the three microbial assay systems. The sensitivity and reliability of the new Polytox® toxicity procedure is discussed.