Genotoxicity testing of air samples from cities of Slovakia detected by the comet assay in human cells

The alkaline comet assay modified with endonuclease III was used to investi gate the potential mutagenic effects of air samples from 12 localities in S lovakia during the course of a year. As target cells, freshly isolated huma n peripheral lymphocytes and transformed human liver HepG2 cells were used. DNA strand breaks and oxidised pyrimidines with AP sites were measured aft er the treatment with different concentrations of extracts from the 48 air samples. 32 samples were used to test organic compounds present in air samp les (dichloromethane extracts), and 16 samples for evaluation of aqueous ex tracts from filters. Preliminary analyses show that 2/3 of samples extracte d by dichloromethane induced higher DNA damage in HepG2 cells and almost 1/ 3 in lymphocytes. 3/4 of aqueous extracts induced a strong positive effect in HepG2 cells, none of them in lymphocytes. Comparing preliminary results from all localities and from different samplings during the course of the y ear, we found winter samples to be more mutagenic than summer samples.