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Microplastics in European sea salts – An example of exposure through consumer choice and of interstudy methodological discrepancies

Microplastics in European sea salts – An example of exposure through consumer choice and of interstudy methodological discrepancies
Microplastics in European sea salts – An example of exposure through consumer choice and of interstudy methodological discrepancies

Microplastics are contaminants of emerging concern, not least due to their global presence in marine surface waters. Unsurprisingly, microplastics have been reported in salts harvested from numerous locations. We extracted microplastics from 13 European sea salts through 30% H 2O 2 digestion and filtration over 5-µm filters. Filters were visually inspected at magnifications to x100. A subsample of potential microplastics was subjected to Raman spectroscopy. Particle mass was estimated, and human dose exposure calculated. After blank corrections, median concentrations were 466 ± 152 microplastics kg -1 ranging from 74 to 1155 items kg -1. Traditionally harvested salts contained fewer microplastics than most industrially harvested ones (t-test, p < 0.01). Approximately 14 µg of microplastics (< 12 particles) may be absorbed by the human body annually, of which a quarter may derive from a consumer choosing sea salt. We reviewed existing studies, showing that targeting different particle sizes and incomplete filtrations hinder interstudy comparison, indicating the importance of method harmonisation for future studies. Excess salt consumption is detrimental to human health; the hazardousness of ingesting microplastics on the other hand has yet to be shown. A portion of microplastics may enter sea salts through production processes rather than source materials.

Human exposure, Marine foods, Method harmonisation, Microplastic ingestion, Salt harvesting techniques
0147-6513
Thiele, Christina Johanna
7119e77e-cc82-4ccc-b675-162aa8109491
Grange, Laura J.
7194fc9a-ed65-41ff-af8f-bdc67f541f26
Haggett, Emily
6dc0983a-b87f-410f-8567-f046d5a44c27
Hudson, Malcolm
1ae18506-6f2a-48af-8c72-83ab28679f55
Hudson, Philippa
399cf704-5e0a-481a-a6e5-83397974b274
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Zapata-Restrepo, Lina M.
05a5bba1-27a9-4210-b350-df4ea7e496d8
Thiele, Christina Johanna
7119e77e-cc82-4ccc-b675-162aa8109491
Grange, Laura J.
7194fc9a-ed65-41ff-af8f-bdc67f541f26
Haggett, Emily
6dc0983a-b87f-410f-8567-f046d5a44c27
Hudson, Malcolm
1ae18506-6f2a-48af-8c72-83ab28679f55
Hudson, Philippa
399cf704-5e0a-481a-a6e5-83397974b274
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Zapata-Restrepo, Lina M.
05a5bba1-27a9-4210-b350-df4ea7e496d8

Thiele, Christina Johanna, Grange, Laura J., Haggett, Emily, Hudson, Malcolm, Hudson, Philippa, Russell, Andrea E. and Zapata-Restrepo, Lina M. (2023) Microplastics in European sea salts – An example of exposure through consumer choice and of interstudy methodological discrepancies. Ecotoxicology and Environmental Safety, 255, [114782]. (doi:10.1016/j.ecoenv.2023.114782).

Record type: Article

Abstract

Microplastics are contaminants of emerging concern, not least due to their global presence in marine surface waters. Unsurprisingly, microplastics have been reported in salts harvested from numerous locations. We extracted microplastics from 13 European sea salts through 30% H 2O 2 digestion and filtration over 5-µm filters. Filters were visually inspected at magnifications to x100. A subsample of potential microplastics was subjected to Raman spectroscopy. Particle mass was estimated, and human dose exposure calculated. After blank corrections, median concentrations were 466 ± 152 microplastics kg -1 ranging from 74 to 1155 items kg -1. Traditionally harvested salts contained fewer microplastics than most industrially harvested ones (t-test, p < 0.01). Approximately 14 µg of microplastics (< 12 particles) may be absorbed by the human body annually, of which a quarter may derive from a consumer choosing sea salt. We reviewed existing studies, showing that targeting different particle sizes and incomplete filtrations hinder interstudy comparison, indicating the importance of method harmonisation for future studies. Excess salt consumption is detrimental to human health; the hazardousness of ingesting microplastics on the other hand has yet to be shown. A portion of microplastics may enter sea salts through production processes rather than source materials.

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Accepted/In Press date: 13 March 2023
Published date: 15 April 2023
Additional Information: Funding Information: This work was supported by the EPSRC Doctoral Programme, a Southampton Marine and Maritime Institute Leverhulme Trust Doctoral Scholarship , and the Blue Marine Foundation, London, UK . The funding bodies did not have any involvement in this study. Publisher Copyright: © 2023 The Authors
Keywords: Human exposure, Marine foods, Method harmonisation, Microplastic ingestion, Salt harvesting techniques

Identifiers

Local EPrints ID: 476076
URI: http://eprints.soton.ac.uk/id/eprint/476076
ISSN: 0147-6513
PURE UUID: a574079b-9a68-4312-8bda-43a474488bea
ORCID for Christina Johanna Thiele: ORCID iD orcid.org/0000-0002-3160-1189
ORCID for Andrea E. Russell: ORCID iD orcid.org/0000-0002-8382-6443

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Date deposited: 12 Apr 2023 11:37
Last modified: 17 Mar 2024 02:46

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Contributors

Author: Laura J. Grange
Author: Emily Haggett
Author: Malcolm Hudson
Author: Philippa Hudson

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