PAHs associated with the leaves of three deciduous tree species. I - concentrations and profiles.

Howsam, Mike and Jones, Kevin C. and Ineson, Philip (2000) PAHs associated with the leaves of three deciduous tree species. I - concentrations and profiles. Environmental Pollution, 108 (34). pp. 413-424. ISSN 0269-7491

Abstract

Results for the concentrations of total polycyclic aromatic hydrocarbons (ΣPAH) and the PAH profile in leaves from three deciduous tree species from the same woodland are presented, and discussed with reference to environmental and leaf-related variables. There were significant differences between oak, ash and hazel leaves in their ΣPAH concentrations (sum of 23 PAHs), and in the relative contribution of individual PAHs to the sum. Leaves exhibiting pubescence (hairiness) were found to have significantly higher ΣPAH concentrations than hairless leaves, regardless of their position in the vegetation strata of the wood. Hazel leaves from the understorey had a PAH profile consisting of a greater proportion of the 4-, 5- and 6-ring PAHs than oak or ash from the canopy. This was concluded to be the result of the filtering effect of the main canopy on the air passing over and through it, with subsequent transfer of particles and attendant PAHs to the understorey below. The proportion of ΣPAH contributed by the 6-ring PAH in hazel leaves was negatively correlated with distance from the southern edge of the canopy. It is proposed that the predominantly windward edges of the woodland, where atmospheric turbulence is likely to be greatest, favoured the deposition of particle-bound PAHs to leaves.