Turbidity and Color Correction in the Microtox™ Bioassay~!2009-08-13~!2009-12-24~!2010-03-02~!

Abstract

We propose a new method of correcting for the effects of color and turbidity on bacterial light output meas- urements in the Microtox bioassay. Using our method, toxicity assessment involves clearly defined calculation factors, based on light loss measurements using a modified double-cuvette. An existing color-correction method requires additional spectrometer measurements and over-corrects for turbidity. For a range of clear, colored fluids our new method and the existing method gave similar, corrected EC50 values. Our new method needs no separate equipment and is likely to provide valid toxicity assessments of whole fluids, without any need for sample clarification. It accounted for > 90 % of the variance in loss of measured bacterial light caused by color and turbidity of a range of test fluids.