ISO/DIS 10871 (2009)
The test assesses effects of water soluble and chemical bonded pollutants of natural sample material such as soil, sludge and waste on the dehydrogenase activity of Arthrobacter globiformis.
The toxicity is determined by measuring the dehydrogenase activity of Arthrobacter globiformis using the redox dye resazurine. Dehydrogenases, as respiratory chain enzymes of microorganisms, are essential components for biological transformations. Because the dehydrogenase activity correlates with the metabolic activity of the cells, the quantity of Resorufin is a measure for the toxicity of the test substance. The increase of Resorufin is determined by measuring the fluorescence every 15min for a period of one hour. To determine the inhibition of the dehydrogenase activity the rate of increase of resorufin in the sample is related to the rate of increase of resorufin in a control.