AIR-POLLUTION MONITORING BY LICHENS IN A SMALL MEDIEVAL TOWN OF CENTRAL ITALY

Air quality and the deposition pattern of trace elements were assessed in Siena (Central Italy) using epiphytic lichens. Air quality was ass essed in terms of the Index of Atmospheric Purity (IAP) based on frequ ency counts of lichen species in 25 stations in the urban area. Forty- six species of epiphytic lichens were found. There were no lichen dese rt areas and some widespread species of lichens which could facilitate future surveillance monitoring programmes were identified. Trace elem ent deposition was estimated by analysing the thalli of Parmelia caper ata, collected in 28 urban sites, Among the elements considered (Al, B , Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, S, Zn) Pb was the most widespread, indicating that despite the progressive introduction of u nleaded fuel this metal is still emitted copiously (and/or resuspended ) by traffic. The results of the two biomonitoring approaches used in the study area were compared.