POTENTIAL GENOTOXICITY OF SEDIMENTS FROM THE GREAT-LAKES

Thirty-eight organic extracts of sediment samples collected from 28 sites in three Great Lakes priority areas (Grand Calumet River, Buffalo River, and Saginaw River) were evaluated with the new activated Mutatox Genotoxicity Assay. This in vitro procaryotic assay used rat hepatic S9 for exogenous metabolic activation and a dark mutant strain of the luminescent bacterium Photobacterium phosphoreum for detection of environmental DNA-damaging substances (genotoxins). A genotoxic response was indicated when the test chemical restored the luminescent state in bacteria; the degree of light increase identified the relative genotoxicity of the sample. Within the three priority areas sampled, 27 sites showed evidence of genotoxins, 23 of 28 sites (82%) were designated genotoxic; 4 were suspect (14%), and 1 was negative (3%). Assay sensitivity to known progenotoxins arylamines (2-aminoanthracene and 2-aminofluorene) and polycyclic arylhydrocarbons [benzo(alpha)pyrene and pyrene] in complex sediment mixtures was less-than-or-equal-to 1 mug per cuvette. The activated Mutatox Assay was a sensitive, specific, predictive, and short-term test for detecting the presence of genotoxins in complex environmental sediments.