Air pollution biomonitoring using successive cladodes of Opuntia ficus-indica : A lead isotopic study
Résumé
Opuntia ficus-indica (Ofi) is a long-domesticated cactus that is widespread throughout arid and semiarid regions of the world. Ofi is grown for both its fruits and edible cladodes, which are flattened photosynthetic stems. Young cladodes develop from mother cladodes, thus forming series of cladodes of different ages. Therefore, successive cladodes may hold some potential for biomonitoring over several years the local atmospheric pollution. In this study, cladodes, roots, dust deposited onto the cladodes, and soil samples, were collected in the vicinity of three heavily polluted sites, i.e. Selaata fertilizer industry (Lebanon), the roadside of a highway near Saida (Lebanon), and the tailings of an abandoned lead-zinc mine (Jebel Ressas in Tunisia). The lead content was analyzed by Atomic Absorption Spectroscopy and ICP-MS, Scanning Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM-EDX) was used to characterize the cladode surfaces and the nature of dust deposit, and the lead isotopes were analyzed to identify the origin of Pb. The results show that (i) Ofi readily bioaccumulates Pb, (ii) the lead isotopic composition of cladodes evidences a foliar pathway of lead into Ofi and identifies the relative contributions of local Pb sources, (iii) the evolution of air quality is effectively recorded with successive cladodes, which makes Ofi a promising biomonitor to be used in environmental and health studies.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...