Field comparison between moss and lichen PAHs uptake abilities based on deposition fluxes and diagnostic ratios

In the present work, PAH uptake ability was tested in oven-devitalized moss (Hypnum cupressiforme) and lichen (Pseudevernia furfuracea) exposed in bags for six weeks in 9 periurban sites of Campania region (southern Italy). Based on a previous pilot work, aims of the study were to verify: i) whether the lichen showed higher PAH uptake and flux; ii) whether the two biomonitors evidenced similar pollution trends over the study area; iii) whether the two biomonitors highlighted similar pollution sources based on specific diagnostic ratios. For most PAHs, the accumulation was significantly higher in the lichen compared to moss, likely due to the ability of the first to entrap PAHs in the thallus and preserve these compounds from degradation during the exposure. In both biomonitors 4-rings PAHs prevailed, followed by 2–3-rings, both in lichen and in moss, whereas a limited accumulation of 5–6-rings PAHs was observed. The better performance of the lichen directly reflected on PAH deposition fluxes, which were significantly higher in the lichen also due to its lower specific leaf area. Despite the different sensitivity of the two species, they provided similar information in all sites, describing the same trend of pollution over the study area. According to diagnostic ratios, both moss and lichen highlighted pyrogenic emissions occurred during the six-week exposure.