INCREASED AQUATIC TOXICITY FOLLOWING PHOTOLYTIC CONVERSION OF AN ORGANOCHLORINE POLLUTANT

In studies of the photolytic degradation of chlorophenolic substances in aqueous media, 2,4,6-trichlorophenol was found to be converted into products with increased toxic effects on the Microtox(R) luminescence bioassay system. The chlorophenol was mainly photohydrolysed at the 2 - or 6- positions and 3,5-dichlorocatechol was formed. The increased t oxic effects were confined to this photolytic product. Although there were indications that the catechol was further modified, it accumulate d in the aquatic medium at the test conditions, and most probably will appear in the aquatic environment upon illumination of the polluted p arent compound. The 2,4,6-trichlorophenol/3,5-dichlorocatechol system here described therefore increases the environmental impact of an abio tic transformation of a polluted organic compound. (C) 1997 Elsevier S cience Ltd.