Papers

20 results
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Article Tier 2

Settling velocity of microplastic particles having regular and irregular shapes

Researchers measured how quickly microplastic particles of various shapes settle through water, testing 66 different particle types including spheres, cylinders, fibers, and irregular fragments. They found that particle shape significantly affects settling speed, with fibers and flat shapes sinking more slowly than spheres of the same size. The study provides new equations for predicting where microplastics end up in oceans and waterways based on their shape.

2023 Environmental Research 86 citations
Article Tier 2

Settling velocity of microplastic particles of regular shapes

This study measured the sinking velocities of spherical, cylindrical, and filament-shaped microplastic particles ranging from 0.5 to 5 mm, finding that shape strongly determines how quickly particles settle through the water column. Understanding settling behavior is essential for modeling how microplastics are transported and deposited in marine environments.

2016 Marine Pollution Bulletin 457 citations
Article Tier 2

Settling Velocities of Small Microplastic Fragments and Fibers

Researchers precisely measured the settling speeds of over 4,000 small microplastic particles in water and found that existing prediction models designed for larger microplastics do not work well for these tiny fragments and fibers. The settling speed depends on each particle's size, density, and shape, with the smallest particles sinking extremely slowly. Understanding how quickly microplastics settle in water is important because it determines how far they travel and how long they remain available to be consumed by aquatic organisms that humans may eventually eat.

2024 Environmental Science & Technology 63 citations
Article Tier 2

Characteristics and Sinking Behavior of Typical Microplastics Including the Potential Effect of Biofouling: Implications for Remediation

Researchers characterized how microplastics of different shapes sink through water, finding that shape is a critical factor, with films behaving very differently from spheres and fibers. The study also examines how biofouling on floating plastics can cause them to sink, with implications for designing filtration and remediation systems.

2020 Environmental Science & Technology 257 citations
Article Tier 2

Settling behaviour of irregular-shaped polystyrene microplastics

Researchers studied the settling behavior of irregular-shaped polystyrene microplastics in water, finding that shape significantly affects how fast particles sink. Understanding settling behavior is important for predicting how microplastics distribute vertically in rivers and ocean water columns.

2021 Science & Technology Development Journal - Engineering and Technology 7 citations
Article Tier 2

Sedimentation of microplastics interacting with sediment

Researchers conducted laboratory settling velocity experiments for 12 different microplastic types with varying shapes in both clear and turbid water, finding that the simultaneous presence of suspended sediments significantly alters MP settling behaviour in ways not captured by existing models that assume clean water conditions.

2025
Article Tier 2

Evaluating settling velocities of microplastics-sediment mixtures under laboratory conditions

This laboratory study investigated how microplastics behave when mixed with natural sediment particles and allowed to settle in water, finding that the combined aggregates settle at different rates than either material alone. Smaller microplastics were particularly prone to forming flocs with sediment, which can accelerate their sinking and burial in riverbeds and lake bottoms. Understanding these settling dynamics is important for predicting where microplastics accumulate in aquatic environments and how they interact with the food chain.

2025 1 citations
Article Tier 2

Sinking rates of microplastics and potential implications of their alteration by physical, biological, and chemical factors

Researchers conducted sinking experiments with diverse microplastic particles and found that sinking velocity depends not only on density and size but also on particle shape, and that biofouling and weathering can substantially alter sinking rates with implications for how microplastics distribute through the water column.

2016 Marine Pollution Bulletin 595 citations
Article Tier 2

Machine learning-based prediction for settling velocity of microplastics with various shapes

Researchers developed machine learning models to predict the settling velocity of microplastics based on their size, density, and shape. They classified microplastic shapes into fiber, film, and fragment categories and identified the optimal shape parameter for each, achieving significantly better prediction accuracy than existing theoretical models. The study reveals that particle size has the greatest influence on settling velocity, which is important for understanding how microplastics move and distribute in water environments.

2023 Water Research 59 citations
Article Tier 2

Empirical Shape-Based Estimation of Settling Microplastic Particles Drag Coefficient

This study experimentally measured the settling behavior of flat square microplastic particles in water, finding that shape significantly affects sinking speed and drag compared to spherical particles. Understanding how microplastic shapes influence settling is essential for modeling where plastics accumulate in rivers and ocean sediments.

2023 Journal of Marine Science and Engineering 2 citations
Article Tier 2

Sedimentation behavior of aggregated microplastics: Influence of particle size and water constituents in environmental waters

Laboratory experiments investigated how aggregation of microplastics with sediments and organic matter affects their sinking rates in water, finding that aggregate composition strongly influences settling velocity. These findings improve models predicting whether microplastics sink to the seafloor or remain suspended in the water column.

2025 The Science of The Total Environment 1 citations
Article Tier 2

An experimental study on microplastic settling velocities in different water environments: Which factors shape the settling process?

Researchers experimentally investigated how biofilm formation and weathering processes affect the settling velocities of microplastics across different water matrices, identifying the key physical and biological factors shaping how particles sink in aquatic environments.

2025 Marine Pollution Bulletin
Article Tier 2

Suspended sediments mediate microplastic sedimentation in unidirectional flows

Researchers found that suspended sediments in water significantly increase microplastic sedimentation rates, with higher sediment concentrations driving greater downward transport of microplastics and creating differential settling patterns based on polymer type.

2023 The Science of The Total Environment 49 citations
Article Tier 2

Settling velocity of irregularly shaped microplastics under steady and dynamic flow conditions

The settling velocities of irregularly shaped microplastics were measured under both still water and dynamic flow conditions, finding that shape strongly affected settling speed and that turbulence caused non-spherical particles to orient and settle differently than spheres, with implications for predicting microplastic vertical transport in rivers and coastal waters.

2021 Environmental Science and Pollution Research 92 citations
Article Tier 2

Towards better predicting the settling velocity of film-shaped microplastics based on experiment and simulation data

Researchers combined experimental and simulation data to better predict how film-shaped microplastics settle through water, since most existing models are based on spherical particles. They found that the particle definition approach was more suitable than equivalent spherical diameter for characterizing flat, irregular microplastics. The improved settling velocity predictions could help scientists better understand how film-shaped microplastics travel and accumulate in aquatic environments.

2024 Marine Pollution Bulletin 10 citations
Article Tier 2

Improved Settling Velocity for Microplastic Fibers: A New Shape-Dependent Drag Model

A new shape-dependent drag model was developed to improve the accuracy of settling velocity predictions for microplastic fibers, addressing a major limitation of existing drag models that significantly underpredict fiber settling in aquatic environments.

2021 Environmental Science & Technology 85 citations
Article Tier 2

Sinking velocity of sub-millimeter microplastic

Researchers measured the sinking velocities of irregularly shaped microplastic particles (polyamide, PMMA, and PET, 6–251 μm) and found they sink considerably slower than theoretical predictions for spheres of equivalent size, developing a predictive model based on particle size and excess density to better represent how real-world microplastics settle through the water column.

2018 Marine Pollution Bulletin 109 citations
Article Tier 2

Effects of Particle Properties on the Settling and Rise Velocities of Microplastics in Freshwater under Laboratory Conditions

Physical experiments quantified the settling and rise velocities of ~500 microplastic particles of varying shapes, sizes, and densities under controlled laboratory conditions, finding velocities ranging from 0.39 cm/s (settling polyamide fibers) to 31.4 cm/s (rising expanded polystyrene), with standard sediment transport formulas inadequate for fibers. The study provides empirical data needed to improve models of microplastic transport in rivers and lakes.

2019 Environmental Science & Technology 425 citations
Article Tier 2

The curious case of microplastic settling velocity within suspended sediment

Researchers investigated the settling velocity of microplastics within suspended sediment in freshwater environments, aiming to better characterize the transport dynamics of these persistent pollutants through the water column. Their analysis highlighted that microplastic settling behavior is complex and context-dependent, complicating predictions of temporal and spatial distribution in rivers.

2025
Article Tier 2

A settling velocity formula for irregular shaped microplastic fragments based on new shape factor: Influence of secondary motions

Researchers developed a new shape factor for irregular microplastic fragments and derived a settling velocity formula based on it, using numerical modeling to show that fragment shape governs whether particles sink stably or oscillate — providing more accurate predictions of microplastic transport in rivers and lakes than existing methods.

2024 The Science of The Total Environment 7 citations