Spatiotemporal patterns in foliar element concentrations in Ficusmicrocarpa L. f. growing in an urban area: implications for biomonitoring studies

Effects of atmospheric pollution and seasonal variation on Al, Ba, Cr, Cu, Fe, Mg, Mn, Pb, V and Zn concentration in Indian laurel (Ficus microcarpa L. f.) leaves were studied in the city of Palermo (Sicily, Italy). Samples were collected from six sampling sites representing either (a) areas of high traffic density or (b) areas further away from traffic (e.g. gardens). Samples were collected every two months during 1998 and 2000. Apart from Ba, Cr and Mn, the elements showed a significant temporal variation but no consistent trends in this were present; the highest (or lowest) values were not detected at some particular time of the year. Results show that the progressive phasing-out of leaded petrol in Italy has resulted in a decrease of Pb, whereas we detected some indications to increased foliar V in the course of time. Even though some spatial patterns were seen in some of the elements, concentrations were not significantly higher in areas representing high traffic density than in samples collected from gardens. Hence, our results do not give unreserved support to use F. microcarpa as a biomonitor.