EVALUATION OF SOS-INDUCING ACTIVITY WITH AN O-ACETYLTRANSFERASE-OVEREXPRESSING STRAIN SALMONELLA-TYPHIMURIUM NM2009 FOR MUNICIPAL RIVER WATER AND THE IDENTIFICATION OF 1-NITROPYRENE

Evaluation of SOS-inducing activity of organic extracts from tributari es of the Yodo River in Kyoto was examined with a highly sensitive umu test system using an O-acetyltransferase(O-ATase)-overexpressing stra in Salmonella typhimurium NM2009 and an O-ATase-defective strain NM200 0. Organic extracts in river water were collected by the XAD-2 resin c olumn method and the blue rayon hanging method at 4 locations througho ut the year. Both XAD-2 resin and blue rayon extracts collected at dow nstream locations from wastewater treatment plants showed higher SOS-i nducing activity than those at the upsream location in the absence and the presence of S9 mix with NM2009. It was also shown that the consti tuents contributing SOS-inducing activity were different between XAD-2 extract and blue rayon extract. No or weak responses of SOS-inducing activity were observed with an O-ATase-defective strain NM2000 among a ll extracts performed. These results indicate that a highly sensitive umu test using an O-ATase-overexpressing strain and an O-ATase-defecti ve strain proved to be an excellent tool for the monitoring of genotox icity attributable to trace amounts of genotoxicants such as direct-ac ting nitroarenes and/or indirect-acting aromatic amines in river water . Further study was made to Identify 1-nitropyrene in XAD-2 resin extr act from municipal river water. Copyright (C) 1996 IAWQ.