Sorption of organic genotoxins to particulate matter in industrial effluents

In an earlier work [White PA et al. (1996): Environ Mot Mutagen 27:116-139] we examined the genotoxicity of dichloromethane extracts from a variety of industrial effluent samples. In this companion work, we used the SOS Chromotest to investigate the sorption of the extracted genotoxins to effluent suspended particulate matter. The affinity of the genotoxins for particulate matter is expressed as a genotoxicity sorption partition coefficient (K-d-genotox. The results indicate that industries known for their emission of combustion by-products, such as polycyclic aromatic hydrocarbons, often have high K-d-genotox values (greater than or equal to 10(6)). These include metal refining and founding industries as well metal surface treatment facilities. In contrast, K-d-genotox values for pulp and paper mills and sewage treatment facilities ore several orders of magnitude lower (less than or equal to 10(4)). In Several cases the calculated K-d-genotox values ore in agreement with the K-ow values of genotoxic substances isolated from genotoxic industrial waste samples studied by other researchers. The sorption partition coefficient, in conjunction with the concentration of available particulate matter, was used to determine the percent of organic genotoxins adsorbed to effluent suspended particulate matter. Values range from 2.3% to 99.8%. High values (>70%) were obtained for metal surface treatment and inorganic and organic chemical production facilities. Low values (<30%) were obtained for sewage treatment facilities and pulp and paper mills. The results also demonstrate the effect of variations in the concentration of available particulate matter on the genotoxicity of both aqueous and particulate extracts. The results suggest that the sorptive properties of the particulate matter itself are reduced when the concentration of particulate matter is very high (> 1,000 mg per I). The use of sorption partition information in inferring the physical-chemical nature of the putative genotoxins and the implications of the results for assessing the hazard posed to aquatic biota by industrial genotoxins ore discussed. (C) 1996 Wiley-Liss, Inc.