MUTAGENICITY OF COAL-DUST AND SMOKELESS-TOBACCO EXTRACTS IN SALMONELLA-TYPHIMURIUM STRAINS WITH DIFFERING LEVELS OF O-ACETYLTRANSFERASE ACTIVITIES

Epidemiological studies have indicated an increased incidence of gastr ic neoplasia in coal miners. Because smokeless tobacco use is prevalen t in the mining industry, nitrites or other components of these produc ts may be etiologically associated with these gastric neoplasms. In th is study both nitrosated and non-nitrosated coal-dust (from West Virgi nia and New Mexico) as well as smokeless-tobacco (snuff and chewing to bacco) extracts were examined for the presence of aromatic amines and nitroarenes by comparing the activities of these extracts in the pre-i ncubation variant of the Ames assay. Salmonella strains with differing O-acetyltransferase activities (TA98 and YG1024) were utilized in thi s investigation. The results of the examination of the coal-dust extra cts indicated positive activity only in the nitrosated extracts. Both nitrosated extracts elicited an increased number of revertants (2-4-fo ld) on YG1024 without S9 in comparison to TA98, suggesting the presenc e of nitroarenes in these extracts. Additionally, the nitrosated West Virginia coal extract showed higher levels of activity on YG1024 with S9, indicating the possible presence of aromatic amines in this comple x mixture. The non-nitrosated smokeless-tobacco extracts showed activi ty only on YG1024 in the presence of S9, with the highest amount of ac tivity occurring in the snuff sample. Except for the chewing-tobacco e xtract on TA98 without S9, positive activity was found in both nitrosa ted tobacco extracts on YG1024 and TA98. As with the coal extracts, th e presence of nitroarenes was inferred for these nitrosated materials. A comparative study of the non-nitrosated snuff extract across 5 test er strains with varying sensitivities to aromatic amines and nitroaren es (TA98NR, TA98/1,8-DNP6, TA98, YG1021 and YG1024) indicated that aro matic amines were a probable source of the mutagenic activity. The cur ing process and/or the addition, of certain flavorants are potential s ources of the mutagenic aromatic amines suggested to be present in the non-nitrosated snuff extract. These findings are consistent with an e tiologic role supplementary to the nitroso compounds for mutagenic nit roarenes and aromatic amines in the development of gastric neoplasia i n coal miners.