Mutagenicity & Genotoxicity in Italian cities

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• Created: Thursday, 26 October 2017 14:12

Airborne particulate matter can include smoke, dust, dirt, soot, and even liquid droplets, if they are small enough.  The particles are emitted into the air and remain suspended in the atmosphere.  Airborne particulate matter has long been recognized as a potential health hazard and, in 2013, was classified as carcinogenic to humans by the International Agency for Research on Cancer.

In this study, the team from Agenzia Regionale Prevenzione Ambiente Energia dell'Emilia Romagna, Sezione di Parma, Italy evaluated and compared mutagenic and genotoxic potencies of particles smaller than 2.5 microns (PM2.5) collected in three seasons, from 2012 to 2015, in five Italian cities.

Mutagenicity was evaluated through the Ames test on the salmonella strains TA98 and TA100.

Clastogenicity was evaluated using the comet assay was carried out on cultured human lung cells (A549). Duplicate slides were prepared for each dose and, in each slide, 100 randomly selected nuclei (200 cells per dose at 250× magnification) were acquired and analyzed with specific image analyser software (Comet Assay IV; Perceptive Instruments/Instem).

Organic matter, extracted from urban particulate matter, was also characterized for polycyclic aromatic hydrocarbons and their derivatives content. The investigators found that samples collected in the colder seasons show the presence of both base pair substitution and frameshift mutagens, with enhanced mutagenic response in the absence of enzyme activation.

The results of this investigation showed that the highest DNA damage (detected with the comet assay) was induced by winter extracts, and this result was different from those of Ames test.  For full experimental results, please refer to the original publication.

Comparing mutagenicity and genotoxicity with chemical concentrations, the scientists found that data from the Ames test correlate with mass concentration and, to a lesser extent, with PAHs.  However, it was also reported that no association was found with their derivatives. DNA damage correlate only with PAHs measured at one site.

The investigators involved with this study believe that these findings demonstrate that to assess the mutagenicity and genotoxicity of complex mixtures it is necessary to use bioassays.  They also believe that the chemical analysis of pollutants does not take into account the possible inhibitory or synergic effects of exposure.

For more information, please refer to the original publication:

Genotoxicity of airborne PM2.5 assessed by salmonella and comet assays in five cities of the Emilia-Romagna (Italy) mutagenicity monitoring network. Environ Mol Mutagen. 2017 Oct 11. Bocchi C, Bazzini C, Fontana F, Pinto G, Cassoni F.