Ecotoxicity, genotoxicity, and oxidative potential tests of atmospheric PM10 particles

The aim of the present work was to investigate the likely toxicological impact of atmospheric PM10 particles by comparing different effect-based methodologies, namely the Vibrio fischeri bioluminescence inhibition bioassay to evaluate ecotoxicity, the SOS Chromotest assay to estimate genotoxicity, and the Dithiothreitol (DTT) and Ascorbic Acid (AA) acellular assays to assess oxidative potential. The chemical composition was characterized for about 30 species, to assess the potential health impact of specific chemical components. Atmospheric particles were collected from spring to summer at a coastal site of the Central Mediterranean, away from large sources of local pollution. The Toxicity Unit (TU) index, used to assess the ecotoxicity, showed that 33% of the samples were toxic. The Induction Factor (IF), generally used to assess particle's genotoxicity, varied from 0.3 to 1.5 that represents the threshold value for genotoxicity. The oxidative potential (OP) determined by the DTT and AA assay varied within the 4.9–34.5 and 4.8–140.6 nmol min−1 range, respectively. DTT-OP and TU values were significantly correlated with OC, EC, and nss-K+, likely because the DTT and Vibrio fischeri responses were mainly associated with species from combustion sources. The IF factor was significantly correlated with some metals (Al, Ba, La, P, Sr, and Ti) likely from traffic sources and did not show any significant correlation with TU and OP values. Overall, paper's results proved the episodic occurrence of ecotoxicity and genotoxicity levels in PM10 particles sampled directly from their natural environment and away from strong pollution sources, highlighting the role mainly of carbonaceous compounds and heavy metals. The impact of spurious correlations between DTT- and AA-OPV and chemical species concentration has also been addressed.