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A MASS BALANCE OF SURFACE WATER GENOTOXICITY IN PROVIDENCE RIVER (RHODE ISLAND USA)
White, P., K T. Ho, T. Ohe, D M. Demarini, AND C. Blaise. A MASS BALANCE OF SURFACE WATER GENOTOXICITY IN PROVIDENCE RIVER (RHODE ISLAND USA). Presented at European Enviromental Mutagen Society, Vilnius, Lithuania, June 30-July 3, 1999.
White and Rasmussen (Mutation Res. 410:223-236) used a mass balance approach to demonstrate that over 85% of the total genotoxic loading to the St. Lawrence River at Montreal is non-industrial. To validate the mass balance approach and investigate the sources of genotoxins in surface waters, we conducted a more thorough study of the Providence River. Samples were collected from selected river sites and WWTFs (wastewater treatment facilities). Organics in filtered samples were concentrated via XAD-2 sorption (acetone elution), or direct partitioning into DCM (dichloromethane). pH adjustment provided initial fractionation into base/neutral and acid extracts. Genotoxicity was measured using the SOS Chromotest and the Salmonella mutagenicity test (TA100, TA9 8 , YG1042, YG1041). Initial analyses revealed potent SOS genotoxicity in the base/neutral surface water extracts, with XAD samples yielding potency values 8-10 times greater than matching DCM extracts. Subsequent Salmonella testing revealed activity in the frameshift strains TA98 and YG1041. An 8 to 10-fold increase in YG1041 potency upon S9 addition suggests the presence of aromatic amines. Overall, the results indicate that most (>50%) of the Providence River genotoxic load enters the system via the Seekonk River. Moreover, discharges from the WWTFs can account for local increases in surface water genotoxicity.