Settling Velocities of Small Microplastic Fragments and Fibers

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(14), P. 6359 - 6369

Published: March 21, 2024

There is only sparse empirical data on the settling velocity of small, nonbuoyant microplastics thus far, although it an important parameter governing their vertical transport within aquatic environments. This study reports velocities 4031 exemplary microplastic particles. Focusing environmentally most prevalent particle shapes, irregular fragments four different polymer types (9–289 μm) and five discrete length fractions (50–600 common nylon polyester fibers are investigated, respectively. All experiments carried out in quiescent water by using a specialized optical imaging setup. The method has been previously validated order to minimize disruptive factors, e.g., thermal convection or interactions, enable precise measurements individual particles (0.003–9.094 mm/s). Based obtained data, ten existing models for predicting particle's terminal assessed. It concluded that models, which were specifically deduced from larger microplastics, fail provide accurate predictions small microplastics. Instead, approach highlighted as viable option computing across continuum terms size, density, shape.

Language: Английский

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How does buoyancy behavior impact microplastic transport in an estuarine environment?

The Science of The Total Environment, Journal Year: 2023, Volume and Issue: 899, P. 165687 - 165687

Published: July 23, 2023

Language: Английский

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A wave-resolving two-dimensional vertical Lagrangian approach to model microplastic transport in nearshore waters based on TrackMPD 3.0

Geoscientific model development, Journal Year: 2025, Volume and Issue: 18(2), P. 319 - 336

Published: Jan. 22, 2025

Abstract. Potentially acting as a source or sink for plastic pollution to the open ocean, nearshore waters remain challenging context predicting transport and deposition of debris. In this study, we present an advanced modeling approach based on SWASH wave model TrackMPD (v3.0) particle investigate dynamics floating sinking microplastics in wave-dominated environments. This introduces novel features such coupling with turbulence models, simulating resuspension bedload processes, implementing settling rising velocity formulations, enabling parallel computation. The laboratory experiments conducted by Forsberg et al. (2020) were simulated validate model's ability reproduce diverse (varying density, shape, size) along comprehensive beach profile, capturing whole water column. Our results underscore robustness proposed model, showing good agreement experimental data. High-density moved onshore near bed, accumulating proximity wave-breaking zone, while distribution low-density particles varied coastal profile depending properties. study also sheds light primary mechanisms driving microplastic transport, Stokes drift, asymmetry, settling/rising velocities. Sensitivity analyses calibration parameters further confirm influence these factors patterns. research establishes SWASH–TrackMPD valuable tool, opening avenues future studies contextualize findings within complexities real-world environments refine our comprehension across different beaches wave-climate conditions.

Language: Английский

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Simulating the ENSO impact on the distribution and fate of floating litter particles in the Northern South China Sea

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 11

Published: Jan. 28, 2025

The Pearl River delivers a large amount of plastic waste to the Estuary (PRE) and adjacent Northern South China Sea (NSCS) region each year. However, transport floating litter after release is difficult predict due complex hydrodynamic conditions caused by climate variability. A regional ocean circulation model coupled with Lagrangian particle tracking utilized in this study simulate distribution fate particles under influence El Niño - Southern Oscillation (ENSO) event. Simulations are conducted during all four seasons (spring, summer, fall, winter) typical Niño, La Niña, ENSO-neutral reveals that most remains within Lingding Bay before being transported westward counterclockwise over NSCS arriving at Qiongzhou Strait. After crossing Strait, debris carried Beibu Gulf, eventually coasts Vietnam Laos. ENSO warm (El Niño) cold (La Niña) phases disrupt patterns modulate runoff, thereby altering pathways grounding probabilities litter. During Niña years, spread wider area, travel longer distances, have lower beaching probabilities. Conversely, year, tend remain for durations, some entrained towards Hong Kong region. This underscores impact mode variability influencing sources, accumulation estuarine-coastal oceans, which will provide critical scientific insights pollution management PRE region, newly identified hotspot microplastic global oceans.

Language: Английский

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Selective oxidative upcycling of PET plastic waste into aniline and terephthalic acid using nitrobenzene

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 160970 - 160970

Published: Feb. 1, 2025

Language: Английский

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Advancing numerical models for land-to-ocean litter transport: A review of hydrodynamic processes and inland contributions

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 970, P. 179013 - 179013

Published: March 1, 2025

Language: Английский

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The density of virgin, consumer and environmental plastics: An investigation using gas displacement pycnometry

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 979, P. 179457 - 179457

Published: April 25, 2025

Density is a fundamental property of plastics and particularly significant in determining the transport fate waste that enter aquatic systems. However, densities are rarely determined environmental literature values employed for modelling or impacts often unsourced derived from secondary databases. In this study, we employ helium displacement pycnometry to determine skeletal non-porous whose polymer composition had been established manufacturer's data, resin codes Fourier transform infrared spectrometry. Two independent, collaborative laboratories, providing measurements within 3.5 % each other with precisions <1 (as relative standard deviation), analysed total 42 virgin, consumer consisting ten common types. Measured all categories, most notably polybutylene terephthalate, polyethylene polypropylene polyvinyl chloride, were outside ranges reported by comprehensive online resource. Possible reasons discrepancies include occurrence dense additives (evaluated X-ray fluorescence analysis), presence inaccessible microscopic pores below laminated surface, contamination main one, structural changes on weathering. Regardless precise causes, results suggest individual polymers have broader range than generally published considered literature. Accordingly, particular where buoyancy critical, more precise, sample-specific recommended.

Language: Английский

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From source to sink: part 1—characterization and Lagrangian tracking of riverine microplastics in the Mediterranean Basin

Environmental Science and Pollution Research, Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 17, 2024

Abstract The Mediterranean Sea is one of the most critically polluted areas due to its semi-enclosed structure and highly anthropized shoreline. Rivers are significant vectors for pollutant transfers from continental marine environment. In this context, a 3D Lagrangian simulation dispersion riverine microplastics (MPs) was performed, which included application recently developed model that reassessed MP fluxes discharged by rivers. physical properties river samples were further investigated approximate vertical displacement in modeled ocean currents. use high-resolution circulation model, integrating Stokes drift, turbulent diffusion, sinking rising velocities, enabled us establish stock balances. Our suggested 65% inputs may be made floating MPs drifting surface layer 35% dense deeper layers. Eastern tends accumulate MPs, primarily originating Western Basin, where major sources concentrated. After 2 years simulation, stranding sequestered 90% inputs, indicating relatively short average residence times few days months at particles sea. Although spatial distribution patterns stabilized after period steady state have been approached, concentrations we generally remained below field observations. This either an underestimation (rivers unaccounted sources), factor 6 most, or overestimation withdrawal through stranding, reduced 90 around 60% less if sinks considered. Graphical abstract

Language: Английский

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Biofilm-induced effect on the buoyancy of plastic debris: An experimental study

Marine Pollution Bulletin, Journal Year: 2023, Volume and Issue: 193, P. 115239 - 115239

Published: July 15, 2023

Plastic floating on the ocean surface represents about 1 % of all plastic in ocean, despite buoyancy most plastics. Biofouling can help to sink debris, which could explain this discrepancy. A set laboratory experiments was conducted investigate biofilm-induced effects different debris. Ten materials densities (buoyant/non-buoyant), sizes (micro/meso/macro), and shapes (irregular/spherical/cylindrical/flat), including facemasks cotton swabs, were evaluated. Biofilm incubated these from a few weeks three months effect growth levels their buoyancy. rising/settling velocities measured compared at seven time-points. The results show hindered for solid materials, while hollow open showed opposite trend early biofilm colonization stages. relationship established between biofilm-growth equivalent sphere diameter that be used improve predictive modeling plastic-debris transport.

Language: Английский

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A wave-resolving 2DV Lagrangian approach to model microplastic transport in the nearshore

Published: July 4, 2024

Abstract. Potentially acting as a source or sink for plastic pollution to the open ocean, nearshore waters remain challenging context predicting transport and deposition of debris. In this study, we present an advanced modelling approach based on SWASH wave model TrackMPD (v3.0) particle investigate dynamics floating sinking microplastics in wave-dominated environments. This introduces novel features such coupling with turbulence models, simulating resuspension bedload processes, implementing settling rising velocity formulations, enabling parallel computation. The laboratory experiments conducted by Forsberg et al. (2020) were simulated validate model's ability reproduce diverse (varying density, shape, size) along comprehensive beach profile, capturing whole water column. Our results underscore robustness proposed model, showing good agreement experimental data. High-density moved onshore near bed accumulating proximity wave-breaking zone, while distribution low-density particles varied coastal profile depending properties. study also sheds light primary mechanisms driving microplastic transport, Stokes drift, asymmetry settling/rising velocities. Sensitivity analyses calibration parameters further confirm influence these factors patterns. research establishes SWASH-TrackMPD valuable tool, opening avenues future studies contextualize findings within complexities real-world environments refine our comprehension across different beaches wave-climate conditions.

Language: Английский

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