Decolourization of triphenylmethane dyes and ecotoxicity of their end products

Common usage of dyes is always connected with pollution of surface water deposits. The goal of the research was to investigate the capability of bacteria and fungi as dyes decolourizing agents. The ecotoxicity of decolourization products was tested with Daphnia magna and Lemna minor. According to ACE 89/BE 2/D3 Final Report Commission EC, dye control samples were classified as toxic. High decolourization effectiveness was not always connected with detoxification. Crystal violet was the most difficult dye to remove (27-76% decolourization) and brilliant green, the easiest (62.5-88.6%). Thymol blue and cresol red were easily removed by fungi (>80%) and poorly by bacteria (<30%). Decolourization of these dyes was mostly connected with an increase of toxicity.