PAHs accumulation on leaves of six evergreen urban shrubs: A field experiment

Özet

Air pollution refers to the occurrence of toxic substances in the atmosphere which results in detrimentaleffects to human beings and living environments. Among the most common atmospheric pollutants,Polycyclic Aromatic Compounds (PAHs) are the most common substances originated by vehicles. The aimof the study was to investigate the accumulation of 16 PAHs in leaves of six evergreen shrubs frequentlyused in Italy for urban landscaping (Elaeagnus x ebbingei, Ilex aquifolium, Laurus nobilis, Ligustrum japonicum,Photinia x fraserii and Viburnum lucidum). The study was conducted in two sites: a public park anda high traffic square. Six samplings were performed in a period of 26 months during Winter. The plantstolerance was investigated considering leaf-extract pH, total chlorophyll, leaf ascorbic acid content andrelative leaf water content. A morphological leaf characterization was also carried out considering stomataldensity and cuticle width. Phenanthrene, fluoranthene, fluorene and pyrene were the majorcompounds yielded in the plant leaves accounting for about 83% of SPAHs, the contributions being 53%,11.3%, 10.5% and 8.5%, respectively. Such compounds are related to vehicular emissions. The analysis ofthe PHAs accumulation and the evaluation of the plants tolerance also revealed that the efficiency intrapping 5- and 6-rings potentially carcinogenic PAHs such as benzo(b)fluoranthene, benzo(k)fluoranthenein plant leaves is highest for Elaeagnus x ebbingei, L. japonicum and L. nobilis while Elaeagnus xebbingei and Photinia x fraserii resulted to be those most tolerant to air pollution. The role of plants inmitigating traffic pollution is confirmed.