PRELIMINARY VEGETATION-BASED EVALUATION OF SEMI-VOLATILE ORGANIC COMPOUNDS (SVOCs) USING PINE SPECIES: TOWARDS POLLUTION DATA COMPARABILITY.

Pine needles are suitable biomonitors of airborne semi-volatile organic compounds (SVOCs). However, the various pine species, each with unique distribution and ecological traits, may differ in their ability to retain pollutants. The SVOC uptake capacities between different vegetation species remain largely unknown, and this study seeks to address this gap. By establishing comparable SVOC retention levels, different species could be used interchangeably, strengthening the data consistency across studies and clarifying diverse pollution cycles. Four SVOC classes - polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) - were analyzed in pine needle samples from various species in 12 sites in Portugal, Spain, the UK and Romania, to explore interspecies pollutant correlations. In general, the SVOC levels found were indicative of the urban fingerprint as expected, despite of the tree species. Although it was not intended to define a clear uptake trend for all species, statistically significant relationships (p<0.05) were found in the most sampled ones (P. pinaster, P. pinea, P. sylvestris) for the total concentration of the SVOCs families for some individual compounds, especially the most volatile. These links appear to be transversal to land use (urban, background/remote), the different climate regimes of the sampled areas, and even the inherent variability of vegetation, allowing for cross-national/land use data to be compared. To enhance the scope of future studies, the spatial and temporal increase of sampling campaigns is needed, although the selection of the appropriate sites can be challenging.