Polycyclic aromatic hydrocarbons and metals in transplanted lichen (Pseudovernia furfuracea) at sites adjacent to a solid-waste landfill in central Italy.

The aim of the study was to evaluate the airborne contamination by polycyclic aromatic hydrocarbons (PAHs) and some heavy metals (arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], nickel [Ni], lead [Pb], and zinc [Zn]) of different pollution scenarios around a solid-waste landfill in central Italy using the lichen Pseudovernia furfuracea as a monitoring tool. For this purpose, eight stations around a landfill characterized by different air pollution sources (industrial, agricultural, residential areas, and roads with different traffic intensities), together with three stations far from the landfill (control areas), were monitored using a set of 22 lichen samples (11 samples analysed for PAHs and metals after 4 months, and 11 samples analysed for metals after 8 months). After 4 months of exposure, the lichen content of all of the analysed elements was greater than that in the pre-exposed lichens. In addition, the Cu and Pb concentration after 8 months was greater than the level after 4 months. The order of metal concentration was Zn > Pb > Cu (or Cu > Pb) > Cr > Ni > As > Cd in all cases. The range of ∑11PAHs concentration was 634-1,371 ng/g dw (three to seven times greater than the amount in the pre-exposed lichens). The ∑11PAHs were dominated (>70 %) by compounds with three aromatic rings. The comparison of the levels of air pollutants among the monitored stations shows nonrelevant spatial patterns between the landfill stations and the control areas; the levels of PAHs and metals found in the lichen samples around the landfill seemed to be more related to the general diffusion of these pollutants in that area.