Relationship between the composition of industrial particles and their transfer in leaves of vegetables
Résumé
The proportion of fine and very fine particles (PM2.5 and PM1) emitted into the atmosphere has significantly increased in industrial areas, since more efficient filters towards coarse particles size fraction are set up in chimney exit facilities. These fine and very fine particles are very reactive and may represent a significant risk for human health and may contaminate the surrounding environments (air, soil, water, vegetable). The micronic and submicronic particles can deeply penetrate into the respiratory system and reach alveoli. Ingestion also represents a significant route of particles exposure through the consumption of contaminated vegetables. Studying the accumulation and transfer of particles trough foliar way in vegetables cultivated near factories emitting metal-rich particles is therefore of major interest. This work concerns the study of foliar accumulation of particles emitted by a lead battery recycling facility and their transfer into the leaf tissues. First, particles were characterized at the particle scale through the coupling of imaging and spectroscopic techniques. Results show that lead is predominantly found in finer size fraction (PM1), mainly as sulfate compounds. We have demonstrated the formation of soluble lead compounds on the particles surface. Secondly, cabbage plants were exposed to particles in the facility courtyard for a 6 weeks period. Results show an important accumulation of lead containing particles in the leaves with sometimes the formation of necrotic areas enriched with metals. In some of these necrosis, Pb speciation changed. Finally, to better understand the bio-physicochemical phenomenon of foliar transfer, exposure of leaves cabbages to different types of monometallic particles were carried out in controlled conditions at the laboratory. The results were subjected to biological tests and have shown significant differences in term of genotoxicity regarding the metal specie considered.