Xiao, Xiao, Sallach, Brett orcid.org/0000-0003-4588-3364 and Hodson, Mark Edward orcid.org/0000-0002-8166-1526 (2025) Biodegradable microplastics adsorb more Cd than conventional microplastic and biofilms enhance their adsorption. CHEMOSPHERE. 144062. ISSN 0045-6535
Abstract
Biodegradable polylactic acid (PLA) mulch has been developed to replace conventional polyethylene (PE) mulch in agriculture to reduce plastic pollution and the accumulation of microplastics (MPs) in soil. Cadmium (Cd) is a significant soil contaminant, and can be adsorbed by MPs. It is increasingly recognised that in the natural environment biofilms can develop on MPs and that this can affect their adsorption properties. We exposed PLA and PE mulches outdoors for 16 months. MPs were then generated from pristine and weathered mulches. Biofilms developed on the weathered plastics. Oxygen-containing functional groups were detected on the weathered, but not the pristine PE, abundance of these groups increased for the weathered PLA. After removal of the biofilm the observed increases in oxygen-containing functional groups relative to the pristine plastics remained. In adsorption experiments pristine PLA MPs had a greater maximum adsorption capacity than pristine PE MPs (106 - 126 vs 23.2 mg / kg) despite having a lower specific surface area (0.325 m2 / g vs 1.82 m2 / g) suggesting that the greater levels of adsorption were due to MP chemistry. The weathered plastics adsorbed more Cd than the pristine plastics (e.g. maximum adsorption capacities of 153 - 185 and 152 mg / kg for the weathered PLA and PE respectively). However, after removal of the biofilm, adsorption of Cd to the weathered MPs was no greater than for the pristine plastics. This suggests that the increased adsorption of Cd due to weathering was caused primarily by adsorption onto the biofilm.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This is an author-produced version of the published paper. Uploaded in accordance with the University’s Research Publications and Open Access policy. |
Keywords: | pristine MPs,natural weathering,biofilm,oxygen-containing functional groups,shape |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Environment and Geography (York) |
Depositing User: | Pure (York) |
Date Deposited: | 08 Jan 2025 10:10 |
Last Modified: | 13 Mar 2025 05:31 |
Published Version: | https://doi.org/10.1016/j.chemosphere.2025.144062 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1016/j.chemosphere.2025.144062 |
Related URLs: | |
Sustainable Development Goals: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:221449 |
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