Micro- and nanoplastics' transfer in freezing saltwater: Implications for their fate in polar waters

• Published in: Environmental Science: Processes & Impacts
• Main Authors: Pradel, Alice, Gautier, Maud, Bavay, Dominique, Gigault, Julien
• Other Authors: Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-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)-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)-Centre National de la Recherche Scientifique (CNRS), Takuvik International Research Laboratory, Université Laval Québec (ULaval)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Arctic; Sea ice
• Online Access: https://insu.hal.science/insu-03341872; https://insu.hal.science/insu-03341872/document; https://insu.hal.science/insu-03341872/file/d1em00280e.pdf; https://doi.org/10.1039/d1em00280e

International audience Plastic debris accumulate in the Arctic by way of oceanic and atmospheric circulation. High concentrations of microplastics (1μm to 5 mm) have been measured, and nanoplastics (<1μm) are expected to be abundant as well. However, little is known about the mobility of micro- and nanoplastics at the seawater/ice interface. This study investigates the fate of micro- and nanoplastics during sea ice formation. A novel experimental approach simulates the growth of sea ice by progressively freezing a saline solution. After different durations of freezing, the concentration of NaCl, natural organic matter, microplastics, and nanoplastics was measured in the ice and liquid. Micro- and nanoplastics’ distribution coefficient between saltwater and ice was determined, reflecting their behavior during congelation sea ice growth. The results show that microplastics are retained in ice while nanoplastics are expulsed from it. Furthermore, natural organic matter plays a crucial role in stabilizing nanoplastics at this interface. These results raise new questions concerning the impact of micro- and nanoplastics in fragile polar environments and the analytical strategy to detect them.