Mutagenesis of PM2.5 water-bioavailable fraction in reference area for atmospheric pollution

Airborne particulate matter (PM) is a pollutant composed of organic and inorganic suspended compounds. Fine inhalable particles (PM2.5) are associated with adverse effects on human health. Organic compounds are most evaluated for genotoxicity, however inorganics adsorbed to PM2.5 can also generate these effects. The study aimed to evaluate whether the fraction of water-soluble inorganic compounds intensifies the mutagenic response compared to those already observed in organic extracts analyzed in an area of reference for air pollution in southern Brazil. Air filters were submitted to aqueous extraction to evaluate PM2.5 inorganic compounds, especially metals, in the water-soluble fraction (WSF). Chemical analysis was performed to quantify metals. Mutagenicity was evaluated using the Salmonella/microsome assay (microsuspension) with strains TA97a, TA98 and TA102, in the presence and absence of rat liver metabolization fraction (±S9). Al, Zn and Cu were found in the largest quantity in the samples, although not indicating elevated mutagenic activity. Most mutagenesis results were positive for the strains and conditions tested, and TA102 was the most sensitive. Comparing the results of mutagenesis among organic (observed in previously studies) and inorganic extract samples for TA98(±S9), the highest responses were detected in the WSF extracts. Therefore, positive responses of WSF elevated the mutagenicity found for the organic fraction of PM2.5, evidencing a sum total of effect as against the different strains tested. According to results the area is no longer a reference for airborne pollution by PM2.5.