Influence of microplate material on the sensitivity of growth inhibition tests with bacteria assessing toxic organic substances in water and waste water

In conjunction with aquatic bioassays, the effect of microplate (MP) material on the sensitivity of a cell multiplication inhibition test with luminescent bacteria (as representatives for unicellular organisms) was examined. The tested substances were four organic chemicals of different hydrophobic properties (4-nitrotoluene, 3,5-dichlorophenol, 2-chloroaniline, sodium phenolate) and waste water from a chemical production plant. The study revealed, that (except for sodium phenolate) the toxic response to the testing material was influenced by the MP material. The employment of the common plastic MP led to an underestimation of the biotests results. Therefore it must be taken into consideration, that when using the microplate technique to expose unicellular organisms to toxic chemicals with hydrophobic properties, only MP made of quartz glass should be employed, (C) 1999 by John Wiley & Sons, Inc.