Leaves of Quercus ilex L. as biomonitors of PAHs in the air of Naples (Italy).

Polycyclic aromatic hydrocarbons (PAHs) were determined by the GC-MS chromatography in leaves of Quercus ilex L., an evergreen mediterranean oak, to monitor the degree of pollution in the urban area of Naples in comparison to rural areas. Leaf samples were collected in July 1998 from four urban parks, six roads and two sites in rural areas. The total PAH content in Q. ilex leaves ranged between 106.6 ng/g d.w. in a control site and 4607.5 ng/g d.w. in a road with a high traffic flow. The mean concentration factors (urban/control) were 3.8 for the parks and 15 for the roads. The contribution of carcinogenic PAH (benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene) was higher in urban areas and different for each site, ranging from 13 to 19%. The total PAH burden in control sites was dominated by the low molecular weight PAH, whilst in the urban roads fluoranthene, pyrene and benz[a]anthracene among the determined PAHs showed the highest values. PAH were positively correlated (P<0.05) to trace metals measured in a previous study.