Polycyclic aromatic hydrocarbons in a bioassay-directed fractionated extract of PM10 collected in São Paulo, Brazil

Polycyclic aromatic hydrocarbons (PAHs) were measured in airborne particles (PM₁₀) collected in an urban site of São Paulo City, Brazil. Samples were Soxhlet extracted sequentially with dichloromethane and acetone, followed by solid phase fractionation. Increasing polar fractions (A–K) of dichloromethane and acetone extracts were obtained. Fractionated extracts were analyzed by gas chromatography/mass spectrometry and Salmonella microsuspension bioassay. Sixteen PAH compounds were quantified in dichloromethane B and C fractions, nevertheless the D and E fractions presented higher mutagenic activities. Concentrations of the individual PAHs ranged from 0.8 ng m⁻³ (perylene) to 12.8 ng m⁻³ (benzofluranthene), reaching a total concentration of 95.5 ng m⁻³. BaP/BgP and Pyr/BaP ratios indicated the presence of vehicular emissions and BghiP/Ind and Chr/BeP ratios suggested a contribution of wood combustion emissions. Further investigation is still necessary for a better understanding of the PAH sources in the urban atmosphere of São Paulo City.