Seasonal Distribution Characteristics Of Polycyclic Aromatic Hydrocarbons (PAHs) In Saliz Matsudana Leaves

The use of plant leaf as passive atmosphere sampler to detect organic pollutants concentration has been reported by many articles. Study on seasonal distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in Saliz matsudana leaves were done in order to understand temporal distribution of PAHs in plant leaves during its annual growth cycle. Saliz matsudana leaves were collected from bud break to the stage where the leaves falls (May-November2013). The sampling for PAHs on gas and particulate matter was done by using a high volume air sampler (June-November2013). Six kinds of PAHs were determined from Saliz matsudana leaves samples which are ubiquitous in the gas phase in the atmosphere. This study surveyed the seasonal distribution characteristics of PAHs in Saliz matsudana leaves, as well as verified the effect of leaf parameters (leaf area, fat content and specific surface area), temperature and the seasonal variation of PAHs concentrations in the atmosphere on concentration of PAHs in Saliz matsudana leaves. Results showed that total PAHs in Saliz matsudana leaves showed obvious seasonal variation. The lowest and highest total PAHs concentration is88.3ng g-1(dry weight) in spring and542.3ng g-1(dry weight) in autumn. During the growing period of Saliz matsudana, contribution of individual PAHs to the total PAHs is as followed: Phenanthrene (51.8%)>fluorene (15.4%)> fluoranthene (11.4%)> pyrene (11.3%)> acenaphthene (5.6%)> anthracene (4.5%). The variation trend of concentration of phenanthrene and total concentration changes were very similar (R2=0.9389). Hence, phenanthrene can be used to study local temporal variation and spatial distribution. By comparing with FLO, PYR, ANT, the percentages of ACE, FLU are higher in summer than in spring and autumn. It deduces that the pollution source of PAHs effected the composition of PAHs. The parameters of Leaves, such as lipid content, surface area and specific surface area were not the key factors in effecting the PAH concentrations during whole annual growth cycle of Saliz matsudana. Variation and percent composition of total PAHs concentrations in Saliz matsudana leaves were similar (R2=0.7094) with PAHs in the air. It implies that PAHs in Saliz matsudana leaves can be a good representative to the changes in atmospheric concentrations of PAHs.