[Influences of pine needles physiological properties on the PAH accumulation]

The lipid contents, specific surface areas and stomata density of two kinds of pine (Cedrus deodar and Pinus thunbergii) needles were determined simultaneously with the levels of polycyclic aromatic hydrocarbons (PAHs). The influences of the physiological properties of two species on the accumulation of PAHs in pine needles were investigated. The PAH concentrations in Cedrus deodar needles are higher than that in Pinus thunbergii needles, and the average total PAH concentrations (PAHs) in two species are (1 101 +/- 692) ng/g and (518 +/- 339) ng/g, respectively. The capabilities of accumulating PAHs for two species are different. The lipid content is the principal factor influencing the levels of pine needle PAHs. In Cedrus deodar and Pinus thunbergii needles, 3-ring (> 56%) and 4-ring (> 31%) PAHs make up large proportions of sigma PAHs. The accumulation capabilities of pine needles for 3-ring PAHs are greater than 4-ring PAHs, and the concentrations of 3-ring PAHs are about two times of those of 4-ring PAHs. There are no significant correlations between the levels of 5- and 6-ring PAHs and lipid contents for two species. For two species, the correlations between lipid contents and specific surface areas are different, which results in the contrary correlations between the PAH levels and specific surface areas for Cedrus deodar and Pinus thunbergii. Specific surface areas and stomata density affect the levels of 5- and 6-ring PAHs in pine needles significantly.