Genotoxic effect of polycyclic aromatic hydrocarbons in the metropolitan area of Porto Alegre, Brazil, evaluated by Helix aspersa (Müller, 1774).

The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM(10-2.5) and PM(< 2.5)). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM(< 2.5)) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions.