GENOTOXICITY OF 2-HALOSUBSTITUTED ENALS AND 2-CHLOROACRYLONITRILE IN THE AMES TEST AND THE SOS-CHROMOTEST

2-Chloroacrolein and 2-bromoacrolein are very potent direkt mutagens n ot requiring metabolic activation in Salmonella typhimurium strains TA 100 and TA 1535. Mutagenic activities decrease with increasing degree of methyl substitution at carbon atom C-3 of the acrolein moiety from 2-chloroacrolein via 2-chlorocrotonaldehyde to 2-chloro-3,3-dimethyla crolein. With 2-chloroacrylonitrile equivocal results are obtained in strain TA 100 without S9-mix and unequivocal with S9-mix. In the SOS-c hromotest the 2-chloroenals are also very strong genotoxins and the st ructure-activity relationships found in the Ames test are clearly conf irmed. 2-Chloroacrylonitrile is not positive in the SOS-chromotest. Th e mutagenic mechanisms are discussed, and indications are provided tha t genotoxicity/mutagenicity depends on formation of DNA adducts, e.g., 1,N-2-cyclic deoxyguanosine adducts.