Mutagenicity Detection of Volatile N-Nitrosamines

A new gas exposure system that measures the mutagenicity of volatile nitrosamines was evaluated. The examinations used to determine the test conditions in this system, using N-nitrosodiethylamine (NDEA) under S9mix conditions, showed the greatest mutagenicity in theE. coliWP2uvrA/pKM101 strain, next in theS. typhimuriumTA100 strain, and no mutagenicity in theS. typhimuriumTA98 strain. The variation coefficients obtained from this system were shown to be comparatively small (3.9-10.8%) . The mutagenic activity of the four nitroso compounds were compared in three assays using the WP2uvrA/pKM101 strain with the S9mix. The order of mutagenic activity obtained was as follows: N-nitrosodi-n-butylamine>N-nitrosodi-n-propylamine > N-nitrosodiethylamine>N-nitrosodimethylamine. The mutagenic detectability with increasing molecular weight of the nitrosamines was as follows: gas exposure system>preincubation assay>plate incorporation assay.