Copper oxide nanoparticle foliar uptake, phytotoxicity, and consequences for sustainable urban agriculture

Tiantian Xiong (1) , Camille Dumat (2, 3) , Vincent Dappe (4) , Hervé Vezin (4) , Eva Schreck (5) , Muhammad Shahid (6) , Antoine Pierart (7) , Sophie Sobanska (4)

1 School of Life Science
2 ENSAT - École nationale supérieure agronomique de Toulouse
3 CERTOP - Centre d'Etude et de Recherche Travail Organisation Pouvoir
4 LASIRE - Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516
5 GET - Géosciences Environnement Toulouse
6 CIIT - COMSATS Institute of Information Technology [Islamabad]
7 Environmental Science and Biochemistry Ecotoxicology Laboratory

Throughout the world, urban agriculture supplies fresh local vegetables to city populations. However, the increasing anthropogenic uses of metal-containing nanoparticles (NPs) such as CuO-NPs in urban areas may contaminate vegetables through foliar uptake. This study focused on the CuO-NP transfer processes in leafy edible vegetables (i.e., lettuce and cabbage) to assess their potential phytotoxicity. Vegetables were exposed via leaves for 5, 10, or 15 days to various concentrations of CuO-NPs (0, 10, or 250 mg per plant). Biomass and gas exchange values were determined in relation to the Cu uptake rate, localization, and Cu speciation within the plant tissues. High foliar Cu uptake occurred after exposure for 15 days for lettuce [3773 mg (kg of dry weight)-1] and cabbage [4448 mg (kg of dry weight)-1], along with (i) decreased plant weight, net photosynthesis level, and water content and (ii) necrotic Cu-rich areas near deformed stomata containing CuO-NPs observed by scanning electron microscopy and energy dispersive X-ray microanalysis. Analysis of the CuO-NP transfer rate (7.8-242 μg day-1), translocation of Cu from leaves to roots and Cu speciation biotransformation in leaf tissues using electron paramagnetic resonance, suggests the involvement of plant Cu regulation processes. Finally, a potential health risk associated with consumption of vegetables contaminated with CuO-NPs was highlighted.

Mots clés: Agriculture; Health risks; Histology; Magnetic resonance; Metal nanoparticles; Nanoparticles; Paramagnetic resonance; Plants (botany); Scanning electron microscopy; Tissue; Vegetables; copper oxide nanoparticles; Energy dispersive x ray microanalysis; Metal-containing nanoparticles; Potential health risks; Regulation process; Transfer process; Transfer rates; Urban agricultures; copper oxides; copper oxide nanoparticle; Copper; Metal nanoparticle; Oxide; alternative agriculture; Biotransformation; Fertilizer application; Gas exchange; Health risk; Nanoparticle; Photosynthesis; Phytotoxicity; Speciation (chemistry); Translocation; Urban agriculture; Water content; agriculture; Article; Biomass; Cabbage; Electron spin resonance; Energy dispersive x ray spectroscopy; Human; Leaf tissue; Lettuce; Stomatal conductance; Urban area; Vegetable; Electron probe microanalysis; Metabolism; brassica oleracea var. capitata; Lactuca; Oxides

Domaines: Chimie théorique et/ou physique

Tiantian Xiong, Camille Dumat, Vincent Dappe, Hervé Vezin, Eva Schreck, et al.. Copper oxide nanoparticle foliar uptake, phytotoxicity, and consequences for sustainable urban agriculture. Environmental Science and Technology, 2017, 51 (9), pp.5242 - 5251. ⟨10.1021/acs.est.6b05546⟩. ⟨hal-01586148⟩