VENEL, Zélie; TABUTEAU, Hervé; PRADEL, Alice; PASCAL, Pierre-Yves; GRASSL, Bruno; EL HADRI, Hind; BAUDRIMONT, Magalie; GIGAULT, Julien

doi:10.1021/acs.est.0c07545

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VENEL, Zélie
Géosciences Rennes [GR]

TABUTEAU, Hervé
Institut de Physique de Rennes [IPR]

PRADEL, Alice
Géosciences Rennes [GR]

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Article de revue

Ce document a été publié dans

Environmental Science and Technology. 2021-03-02, vol. 55, n° 5, p. 3001-3008

Résumé en anglais

The aim of this study is to demonstrate how the flow and diffusion of nanoplastics through a salinity gradient (SG), as observed in mangrove swamps (MSPs), influence their aggregation pathways. These two parameters have never yet been used to evaluate the fate and behavior of colloids in the environment, since they cannot be incorporated into classical experimental setups. Land-sea continuums, such as estuaries and MSP systems, are known to be environmentally reactive interfaces that influence the colloidal distribution of pollutants. Using a microfluidic approach to reproduce the SG and its dynamics, the results show that nanoplastics arriving in a MSP are fractionated. First, a substantial fraction rapidly aggregates to reach the microscale, principally governed by an orthokinetic aggregation process and diffusiophoresis drift. These large nanoplastic aggregates eventually float near the water's surface or settle into the sediment at the bottom of the MSP, depending on their density. The second, smaller fraction remains stable and is transported toward the saline environment. This distribution results from the combined action of the spatial salt concentration gradient and orthokinetic aggregation, which is largely underestimated in the literature. Due to nanoplastics' reactive behavior, the present work demonstrates that mangrove and estuarine systems need to be better examined regarding plastic pollution.< Réduire

Mots clés en anglais

Nanoplastics

aggregation

salinity

microfluidics

environmental

URI

https://oskar-bordeaux.fr/handle/20.500.12278/188128

DOI

http://dx.doi.org/10.1021/acs.est.0c07545

Project ANR

Nanoparticules de plastiques dans l'environnement: source, impact et prédiction - ANR-17-CE34-0008

Unités de recherche

EPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805