Environmental fate and behavior of nanoplastics : Implication of physico-chemical processes

Abstract : Plastics are the third most-produced material on Earth and a significant proportion (>25%) ends up in the environment. To elucidate the risks that this contamination can cause, it is necessary to track the sources, transport pathways, and sinks of plastic debris in the environment. Thi...

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Bibliographic Details
Main Author: Pradel, Alice
Other Authors: Géosciences Rennes (GR), Université de Rennes 1 (UR1)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes 1 (UR1)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université Rennes 1, Julien Gigault
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: HAL CCSD 2021
Subjects:
Contamination
Colloid
Transport
Transfer
Organic Matter
Colloïde
Transfert
Matière organique
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Sea ice
Online Access:https://theses.hal.science/tel-03597424
https://theses.hal.science/tel-03597424/document
https://theses.hal.science/tel-03597424/file/PRADEL_Alice.pdf
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Summary:Abstract : Plastics are the third most-produced material on Earth and a significant proportion (>25%) ends up in the environment. To elucidate the risks that this contamination can cause, it is necessary to track the sources, transport pathways, and sinks of plastic debris in the environment. This has proven difficult since plastic degrades into particles that are too small to sample and quantify. In particular, nanoplastics (<1μm), which are colloidal particles, could form a substantial fraction of the global budget of plastic debris. Therefore, the goal of this was to investigate where nanoplastics may accumulate, by studying physicochemical processes in lab experiments. Throughout this work, special attention has been devoted to the environmental relevance of the nanoplastic models used. First, nanoplastics’ aggregation dynamics was investigated since it impacts downstream transport processes. Then, this work studied nanoplastics' transfer through two environmental interfaces. These have physicochemical gradients suspected to control nanoplastics’ fate: porous media (as a proxy for soils, sediments and aquifers) and the interface between saltwater and ice (as a proxy for seawater/sea ice interfaces). This study shows that the different behaviors of the nanoplastic model are attributable to their sizes, shapes and surface properties that modify their hydrodynamic behaviors and interaction energies. Résumé : Les plastiques sont le troisième matériau le plus produit sur Terre et une importante fraction (>25%) se retrouve dans l'environnement. Pour évaluer les risques liés aux débris plastiques, il est nécessaire de comprendre les sources, et les mécanismes de transport et d’accumulation des débris plastiques dans l'environnement. Ceci s'avère difficile car le plastique se dégrade en particules qui sont trop petites pour être échantillonnées et quantifiées. En particulier, les nanoplastiques (< 1 μm), qui sont des particules colloïdales, pourraient constituer une fraction importante du budget global ...

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