Reliability of the Bacterial Luminescence Assay for Determination of the Toxicity of Pure Compounds and Complex Effluents

The bacterial luminescence toxicity assay has been under development for 2 years. The assay procedure has been significantly improved in that five dilutions of a toxicant or effluent can be assayed simultaneously along with a control. A median effective concentration (EC₅₀) can be generated 30 min after sample collection. The reproducibility of the assay using sodium lauryl sulfate as a standard displayed a coefficient of variation of 15 to 20 percent. The data presented compare Microtox EC₅₀ data for pure compounds and literature data on median lethal concentrations (LC₅₀) for fish. In addition, over 50 complex effluent samples were assayed with Microtox. These same samples were assayed simultaneously using standard fish testing procedures. The data show that a good correlation exists between the bacterial luminescence assay and conventional testing procedures.