Developing a systematic method for extraction of microplastics in soils
Developing a systematic method for extraction of microplastics in soils
Microplastics are an environmental issue of global concern. Although they have been found in a range of environments worldwide, their contamination in the terrestrial environment is poorly understood. The lack of standardised methods for their detection and quantification is a major obstacle for determining the risk they pose to soil environments. Here we present a systematic comparison of microplastic extraction methods from soils, taking into account the characteristics of the soil medium to determine the best methods for quantification. The efficiency of organic matter removal using hydrogen peroxide, potassium hydroxide and Fenton's reagent was measured. Soils with a range of particle size distribution and organic matter content were spiked with a variety of microplastic types. Density separation methods using sodium chloride, zinc chloride and canola oil were tested. Recovery efficiencies were calculated and the impact of the reagents on the microplastics was quantified using Attenuated Total Reflectance (ATR) Fourier Transform-Infrared (FTIR) spectroscopy. The optimal organic removal method was found to be hydrogen peroxide. The recovery efficiency of microplastics was variable across polymer types. Overall, canola oil was shown to be the optimal method for density separation, however, efficiency was dependent on the amount of organic matter in the soil. This outcome highlights the importance of including matrix-specific calibration in future studies considering a wide range of microplastic types, to avoid underestimation of microplastic contamination. We show here that methods for extracting microplastics from soils can be simple, cost-effective and widely applicable, which will enable the advancement of microplastic research in terrestrial environments.
mircoplastics, soils, extraction, density separation, Analytical method
1695-1705
Radford, Freya
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Zapata Restrepo, Lina
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Horton, Alice A.
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Hudson, Malcolm
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Shaw, Peter
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Williams, Ian
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22 March 2021
Radford, Freya
f43f5d73-b100-424a-9021-8f17f7715e35
Zapata Restrepo, Lina
2276abeb-952d-4475-9620-bd0885291f64
Horton, Alice A.
3b4dfc8c-2a5d-48c9-8c63-8a113a2a1bfe
Hudson, Malcolm
1ae18506-6f2a-48af-8c72-83ab28679f55
Shaw, Peter
935dfebf-9fb6-483c-86da-a21dba8c1989
Williams, Ian
c9d674ac-ee69-4937-ab43-17e716266e22
Radford, Freya, Zapata Restrepo, Lina, Horton, Alice A., Hudson, Malcolm, Shaw, Peter and Williams, Ian
(2021)
Developing a systematic method for extraction of microplastics in soils.
Analytical Methods, 13 (14), .
(doi:10.1039/D0AY02086A).
Abstract
Microplastics are an environmental issue of global concern. Although they have been found in a range of environments worldwide, their contamination in the terrestrial environment is poorly understood. The lack of standardised methods for their detection and quantification is a major obstacle for determining the risk they pose to soil environments. Here we present a systematic comparison of microplastic extraction methods from soils, taking into account the characteristics of the soil medium to determine the best methods for quantification. The efficiency of organic matter removal using hydrogen peroxide, potassium hydroxide and Fenton's reagent was measured. Soils with a range of particle size distribution and organic matter content were spiked with a variety of microplastic types. Density separation methods using sodium chloride, zinc chloride and canola oil were tested. Recovery efficiencies were calculated and the impact of the reagents on the microplastics was quantified using Attenuated Total Reflectance (ATR) Fourier Transform-Infrared (FTIR) spectroscopy. The optimal organic removal method was found to be hydrogen peroxide. The recovery efficiency of microplastics was variable across polymer types. Overall, canola oil was shown to be the optimal method for density separation, however, efficiency was dependent on the amount of organic matter in the soil. This outcome highlights the importance of including matrix-specific calibration in future studies considering a wide range of microplastic types, to avoid underestimation of microplastic contamination. We show here that methods for extracting microplastics from soils can be simple, cost-effective and widely applicable, which will enable the advancement of microplastic research in terrestrial environments.
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Accepted/In Press date: 8 March 2021
e-pub ahead of print date: 22 March 2021
Published date: 22 March 2021
Additional Information:
Funding Information:
This work was supported by Engineering and Physical Sciences Research Council funded Centre for Doctoral Training in Sustainable Infrastructure Systems (‘Managing emerging pollutants in waste water systems’, grant number EP/L01582X/ 1); and Southern Water. We would like to thank Peter Morgan and Dr John James Fielding for their advice and technical support in the laboratory.
Publisher Copyright:
© The Royal Society of Chemistry.
Keywords:
mircoplastics, soils, extraction, density separation, Analytical method
Identifiers
Local EPrints ID: 449987
URI: http://eprints.soton.ac.uk/id/eprint/449987
ISSN: 1759-9660
PURE UUID: 0d77f7da-4719-4402-a82e-231cb2e217dc
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Date deposited: 01 Jul 2021 16:34
Last modified: 06 Jun 2024 01:43
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Author:
Freya Radford
Author:
Lina Zapata Restrepo
Author:
Alice A. Horton
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