Leaves of Lolium multiflorum 'Lema' and tropical tree species as biomonitors of polycyclic aromatic hydrocarbons.

This study extends the current knowledge regarding the use of plants for the passive accumulation of anthropogenic PAHs that are present in the atmospheric total suspended particles (TSP) in the tropics and sub-tropics. It is of major relevance because the anthropic emissions of TSP containing PAHs are significant in these regions, but their monitoring is still scarce. We compared the biomonitor efficiency of Lolium multiflorum 'Lema' and tropical tree species (Tibouchina pulchra and Psidium guajava 'Paluma') that were growing in an intensely TSP-polluted site in Cubatão (SE Brazil), and established the species with the highest potential for alternative monitoring of PAHs. PAHs present in the TSP indicated that the region is impacted by various emission sources. L. multiflorum showed a greater efficiency for the accumulation of PAH compounds on their leaves than the tropical trees. The linear regression between the logBCF and logKoa revealed that L. multiflorum is an efficient biomonitor of the profile of light and heavy PAHs present in the particulate phase of the atmosphere during dry weather and mild temperatures. The grass should be used only for indicating the PAHs with higher molecular weight in warmer and wetter periods.