RESUMO
Ambient particulate matter (PM) collected in the vicinity of five industries (Cement, Chemical, Thermal power plant, Sponge-iron and Steel) in Tamil Nadu state, India was characterized for size distribution, metals and polycyclic aromatic hydrocarbons (PAHs) content. Genotoxicity of PM and organic matter (OM) extracted from PM was measured in human lung cancer cell-line, A549 and in human liver carcinoma cell-line, HepG2, respectively, using the comet assay. PM values varied from 57.0 µg/m(3) of air at Cement industry upstream to 561.0 µg/m(3) of air at Sponge iron industry downstream samples. Their metal content varied from 5.758 µg/m(3) of air at Chemical industry to 46.144 µg/m(3) of air at Sponge iron industry and PAH concentration varied from 0.5 ng/m(3) air in upstream Thermal power plant to 3302.4 ng/m(3) air in downstream Sponge iron industry samples. While all PM samples induced DNA strand breaks at higher dose levels, downstream samples of Steel and Sponge iron industries which contained relatively higher concentrations of PAHs and metals and exhibited higher levels of pro-oxidant activity as measured by DTT activity induced significantly higher levels of DNA damage in HepG2 and A549 cells. Pretreatment of A549 cells with vitamin C or quercetin significantly reduced PM induced DNA strand breaks.