Plastic pollution could linger at ocean surfaces for over a century, new research finds
Scientists at Queen Mary University of London have developed a model showing how buoyant plastics gradually sink through ocean layers — predicting it could take more than a century for surface plastic waste to naturally disappear
image:
How plastic sinks to the deep sea — over time, sunlight and waves break large plastic items into tiny fragments that stick to marine snow. These particles gradually sink through the ocean, carrying microplastics from the surface to the seafloor.
view moreCredit: Wu N, Grieve S, Manning A, Spencer K. 2025 Coupling fragmentation to a size-selective sedimentation model can quantify the long-term fate of buoyant plastics in the ocean. Phil. Trans. R. Soc. A 383: 20240445. https://doi.org/10.1098/rsta.2024.0445
Scientists from the Department of Geography and Environmental Science at Queen Mary University of London have developed a simple model to show how buoyant plastic can settle through the water column and they predict it could take over 100 years to remove plastic waste from the ocean’s surface.
Published today in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, the study is the third and final paper in a trilogy that explores the long-term fate of microplastic in the ocean. It builds on earlier research featured in Nature Water and Limnology & Oceanography, offering a complete picture of how plastic pollution moves from ocean surface to seafloor.
The study was led by researchers from the Department of Geography and Environmental Science at Queen Mary University of London, in collaboration with HR Wallingford Ltd. It combines expertise in marine geochemistry, fluid dynamics, and environmental modelling to simulate how plastics move from the ocean surface to the deep sea over time.
The research reveals that even if all plastic inputs into the ocean were stopped immediately, fragments of buoyant plastic debris would continue to pollute the ocean surface and release microplastics for more than a century.
Using a model that simulates the slow breakdown of large plastic particles and their interaction with marine snow (sticky organic material that helps transport debris to the deep sea), the researchers show that the degradation process is the limiting factor in removing plastic from the surface.
Dr Nan Wu, the paper’s lead author from the Department of Geography and Environmental Science at Queen Mary University of London, said:
“People often assume that plastic in the ocean just sinks or disappears. But our model shows that most large, buoyant plastics degrade slowly at the surface, fragmenting into smaller particles over decades. These tiny fragments can then hitch a ride with marine snow to reach the ocean floor, but that process takes time. Even after 100 years, about 10 percent of the original plastic can still be found at the surface.”
The findings help explain the persistent mismatch between the amount of buoyant plastic entering the ocean and the relatively small amounts observed at the surface. This is often referred to as the ‘missing plastic’ problem.
Prof Kate Spencer, co-author and project supervisor from the Department of Geography and Environmental Science at Queen Mary University of London, said:
“This is part of our wider research that shows how important fine and sticky suspended sediments are for controlling microplastic fate and transport. It also tells us that microplastic pollution is an intergenerational problem and our grandchildren will still be trying to clean up our oceans even if we stop plastic pollution tomorrow”.
Prof Andrew Manning, co-author and Principal Scientist at HR Wallingford and Associate Professor at the University of Plymouth, said:
“This study helps explain why so much of the plastic we expect to find at the ocean surface is missing. As large plastics fragment, they become small enough to attach to marine snow and sink. But that transformation takes decades. Even after a hundred years, fragments are still floating and breaking down. To tackle the problem properly, we need long-term thinking that goes beyond just cleaning the surface.”
The model also shows that the biological pump, the ocean’s natural conveyor belt for carbon and particles, may become overwhelmed as plastic production increases. If microplastic concentrations continue to rise, there is a risk they could interfere with ocean biogeochemical cycles.
This work was funded by the Lloyd’s Register Foundation and supported by Queen Mary University of London, HR Wallingford Ltd, and the EU INTERREG Preventing Plastic Pollution project.
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Paper details
Wu, N., Grieve, S., Manning, A. & Spencer, K.L “Coupling fragmentation to a size-selective sedimentation model can quantify the long-term fate of buoyant plastics in the ocean.” Philosophical Transactions A. DOI: [10.1098/rsta.2024.0445]
Authors:
- Dr Nan Wu, Department of Geography, Queen Mary University of London; British Antarctic Survey
- Dr Stuart Grieve, Department of Geography and Digital Environment Research Institute, Queen Mary University of London
- Prof Andrew Manning, HR Wallingford Ltd and School of Biological and Marine Sciences, University of Plymouth
- Professor Kate Spencer, Department of Geography, Queen Mary University of London
Previous papers in the series:
- Nature Water: https://www.nature.com/articles/s44221-024-00332-4
- Limnology & Oceanography: https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lno.12814
Media Enquiries:
For interviews or further information, contact James Cleeton at Queen Mary University of London: j.cleeton@qmul.ac.uk
Journal
Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Coupling fragmentation to a size-selective sedimentation model can quantify the long-term fate of buoyant plastics in the ocean.
Article Publication Date
23-Oct-2025
Dark dyes accelerate plastic fiber release: new insights into ocean microplastic formation
Maximum Academic Press
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Scheme for the prolonged photoaging of different colored PET textiles induced PET microfiber release into surrounding coastal seawater.
view moreCredit: The authors
The findings identify photoaging as a key mechanism converting everyday fabrics into marine microplastics, deepening our understanding of microfiber formation and its ecological risks.
Microplastics smaller than 5 millimeters have raised global concern due to their persistence, toxicity, and ability to accumulate across marine food webs. Synthetic microfibers, the dominant form of microplastics in seawater, often come from PET textiles used in clothing, carpets, and curtains. A single laundry cycle can release more than 700,000 fibers, many of which eventually reach coastal waters. Once in the ocean, these fibers undergo physical and chemical weathering—hydrolysis, mechanical abrasion, and particularly photoaging under sunlight. However, how textile color and dye composition influence this degradation and release process has remained an open question. Addressing this knowledge gap is critical for assessing microfiber generation, persistence, and environmental impact.
A study (DOI:10.48130/newcontam-0025-0001) published in New Contaminants on 05 September 2025 by Xiaoli Zhao’s & Xiaowei Wu team, Chinese Research Academy of Environmental Sciences & Nanjing University of Information Science and Technology, reveals how sunlight-driven photoaging of colored PET textiles, particularly those with dark dyes, accelerates microfiber formation and highlights color as a critical but previously overlooked factor in marine microplastic pollution.
In this study, researchers simulated long-term sunlight exposure by subjecting colored PET textiles to ultraviolet (UV) irradiation in coastal seawater, using multiple imaging and spectroscopic methods to monitor degradation. Scanning electron microscopy (SEM) revealed that UV exposure caused progressive structural damage starting from the warp–weft intersections, leading to the detachment of fibers and increased water turbidity after 12 days, while dark controls showed no change. Quantitative analysis indicated that 0.1 g of PET textile released 47,400 (purple), 37,020 (green), 23,250 (yellow), and 14,400 (blue) microfibers, with fragment sizes ranging from 200–2,000 μm and even nanoscale particles (~0.48 μm in purple fibers). Colorimetry showed significant fading, particularly in purple textiles (ΔE ≈ 23.4), and corresponding microfibers (ΔE ≈ 36.1), while ATR-FTIR confirmed that UV aging increased carbonyl index (CI) values—indicative of oxidation—and decreased crystallinity, reflecting molecular chain scission. Purple PET exhibited the highest CI (2.69) and mass loss (38%), suggesting the most severe photoaging. Mechanistic investigations revealed that dye chemistry played a crucial role: UV–vis spectroscopy demonstrated that purple and green dyes absorbed more UV light than blue and yellow dyes, enhancing free radical reactions. Electron paramagnetic resonance (EPR) and nitroblue tetrazolium (NB) assays detected stronger hydroxyl radical (•OH) generation in darker-colored samples, with purple PET producing the highest concentration (6.20 × 10⁻¹⁵ M) and fastest degradation rate (k′ ≈ 8.71 × 10⁻² h⁻¹). These findings demonstrate that textile color significantly influences microfiber release and aging kinetics, with darker dyes accelerating UV-driven oxidation and fragmentation, ultimately intensifying microfiber pollution in coastal marine environments.
The study provides crucial insights into how colored PET fabrics contribute to microfiber pollution, emphasizing that textile dye composition—not just fiber type—plays a decisive role in microfiber formation. These findings can inform future environmental risk assessments and pollution control strategies. By adjusting dye formulations or selecting pigments with lower UV reactivity, textile manufacturers could significantly reduce the generation of microfibers in marine environments. The research also highlights the need for stricter monitoring of synthetic textile degradation and its chemical byproducts in coastal ecosystems.
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References
DOI
Original Source URL
https://doi.org/10.48130/newcontam-0025-0001
Funding Information
This research was financially supported by the National Natural Science foundation of China (Grant No. 22406091, 41991315, and 41521003), Startup Foundation for Introducing Talent of Nanjing University of Information Science (2024r064), and Natural Science Foundation of Jiangsu Province (BK20240708).
About New Contaminants
New Contaminants is a multidisciplinary platform for communicating advances in fundamental and applied research on emerging contaminants. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of new contaminants research around the world to deliver findings from this rapidly expanding field of science.
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Polyethylene terephthalate microfiber release from textiles in coastal seawater ecosystems under sunlight-driven photochemical transformation
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