Genotoxicity of organic extracts from atmospheric particles

Experiments to evaluate the genotoxic potentialities of urban air particles sampled in Paris (France) after organic solvent extraction have been carried out using four in vitro genotoxicity tests. The two bacterial tests (the Ames test and the SOS Chromotest) demonstrate the genotoxicity of the organic extracts of atmospheric particles; two additional tests (induction of 6-thioguanine mutants and sister chromatid exchanges), carried out on V79 Chinese hamster cells, also confirm these potentialities. These results show clearly that particulate organic extracts induce point mutations in both bacteria and mammalian cells, or the cellular response (SOS repair) to these mutations in bacteria; likewise, they are responsible for clastogenic effects in mammalian cells. Genotoxicity is due either to direct genotoxic chemicals or to active metabolic products of the action of microsomal enzymes. The optimalization of testing procedures is discussed in order to appreciate the contribution of genotoxicity tests to the study of atmospheric pollution.