From leaf to barrier scale: A multisource data evaluation of a spontaneous vegetative barrier to prevent potentially toxic element dispersal

Potentially toxic elements (PTEs) may threaten both environmental and human health due to their persistence and their potential for widespread dispersal through wind and water erosion. Phytoremediation is often evaluated for soil contamination management although vegetation barriers have been less explored to reduce airborne dispersal of PTEs. The current study presents an approach to evaluate trapping capacity of woody species in vegetative barriers by combining field, laboratory measurements and airborne LiDAR point cloud to change scale from a single leaf to the entire vegetative barrier. To upscale leaf PTE concentration to plant and whole barrier estimation, allometric equations were used to evaluate accuracy of LiDAR HD above-ground volume estimation. This approach was tested on a spontaneous vegetative barrier surrounding PTE contaminated brownfields in Marseille (France). Although dense and overlapping shrub and tree canopies made measurements challenging, strong correlations were found between both methods (R 2 = 0.93 and 0.82 for Pinus halepensis and Pistacia lentiscus , respectively). Although PTE concentrations (As, Cd, Cu, Pb, Sb, Zn) in leaves were relatively low compared to those in soils (203 to 6592 times lower), the fraction attributed to atmospheric deposition represented a significant portion of leaf contamination, accounting for 22 % of total Pb and 44 % of total Sb. Similar efficiencies in trapping PTEs were observed between P. halepensis and P. lentiscus. The vegetative barrier, as a whole, can be considered as efficient to restrict contaminated particle dispersal in the studied context. This study underscores the accuracy of combining diverse data sources for robust assessment of nature-based solutions to mitigate contamination, moving beyond leaf-level trapping to a comprehensive barrier-scale evaluation. • Evergreen Mediterranean woody species may trap potentially toxic elements. • As, Cd, Cu, Pb, Sb, Zn in leaf deposits were assessed from leaf to barrier scale. • Open access LiDAR HD data were used to estimate above ground biomass. • Biomass estimation enabled upscale from leaf to multi-species vegetative barrier. • Vegetative barrier may contribute to pollution management at Mediterranean brownfield.