Environmental Genotoxicity in an Estonian Oil Shale Industrial Area

The genotoxicity of environmental samples (ambient air, drinking and river waters, purified waste water and oil shale ash) from an oil shale mining and processing area was studied by using the Ames Salmonella/microsome assay. Salmonella typhimurium strains TA98 and YG1021 were used, with and without metabolic activation with rat liver homogenate S9. The water samples were treated with amberlite adsorbent XAD-2 for concentrating non-polar compounds. The air samples were collected on glass fibre filters by using a high volume air sampler, and extracted with dichloromethane by using a Soxhlet apparatus. The air samples were mutagenic in both strains, both with and without S9-mix. The air mutagenicity data were compared with data from similar tests on cigarette smoke condensate as a positive control. Based on the fact that the average 8-hour respiratory volume at occupational activities is between 10m³ and 20m³, the load of airborne mutagenicity at the cokery plant during one week was estimated to be equal to the mutagenicity produced by the mainstream smoke of one cigarette. The drinking and river water samples were tested with both strains, but no dose-related increases in water counts per plate were noted. The oil shale ash sample showed no mutagenic activity, but showed cytotoxicity at the higher doses tested.