Interpreting the dioxin and furan profiles in the lichen Ramalina canariensis Steiner for monitoring air pollution.

The purpose of this study was to compare the dioxin and furan (PCDD/F) profiles in lichens with those of air and soil. Lichen samples of the species Ramalina canariensis Steiner were collected from 44 different sites and analysed. The results were compared to PCDD/F air and soil profiles from bibliographic data concerning several countries and locations. When compared to other biomonitors (pine needles, vegetation, fruits), lichens were observed to accumulate greater concentrations of PCDD/Fs. The results showed that, although the concentrations of PCDD/Fs in lichens were at the same level of magnitude as those found for soils from the same country (197.5-1218.7 ng kg(-1) and 2.3-15.2 ng I-TEQ kg(-1)), the PCDD/Fs profiles do not reflect soil particle contamination. On the contrary, the PCDD/Fs lichen profiles seemed to be very similar to the ones in the air, at least for the diversity of the ones used for comparison in this study. These results indicated that lichens of the species R. canariensis are potential biomonitors of PCDD/F air pollution.