Papers

61,005 results
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Article Tier 2

Unveiling the Vertical Migration of Microplastics with Suspended Particulate Matter in the Estuarine Environment: Roles of Salinity, Particle Properties, and Hydrodynamics

Researchers studied how suspended particles like clay and sand affect the vertical movement of microplastics in estuarine environments with varying salinity levels. They found that fine clay particles were particularly effective at dragging buoyant microplastics downward through a process of attachment and aggregation. The study reveals that the interplay between sediment type, salinity, and water turbulence plays a major role in determining where microplastics end up in estuaries.

2024 Environmental Science & Technology 34 citations
Article Tier 2

Settling behavior of microplastic hetero-aggregates in aquatic environments with varying salinity

This lab study examined how changes in water saltiness affect whether microplastics clump together with sediment and sink. Increasing salinity encouraged microplastics to form larger aggregates with sediment particles, peaking at moderate salt levels (25 PSU), which influences how quickly they settle out of the water column. Understanding this behavior matters for predicting where microplastics end up in coastal and estuarine environments where fresh and salt water mix.

2025 International Journal of Sediment Research 1 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

Settling of buoyant microplastic in estuaries: The importance of flocculation

Researchers demonstrated that flocculation causes buoyant microplastics to settle 5-21 times faster in estuarine waters than in freshwater, supporting the concept that estuaries act as traps that reduce the overall microplastic load reaching the open ocean.

2023 The Science of The Total Environment 58 citations
Article Tier 2

Transport and retention of sinking microplastics in a well-mixed estuary

Researchers used numerical particle-tracking experiments to examine how sinking microplastics are retained in well-mixed estuaries under varying tidal and freshwater flow conditions. They found that over 90% of sinking particles were retained in the estuary, with retention rates highly sensitive to particle density and size. The study confirms that estuaries can act as significant accumulation zones for microplastics, trapping particles before they reach the open ocean.

2024 Marine Pollution Bulletin 10 citations
Article Tier 2

Transport and sedimentation of microplastics by turbidity currents: Dependence on suspended sediment concentration and grain size

Researchers used laboratory experiments to study how turbidity currents, underwater flows of sediment-laden water, transport and deposit microplastics on the ocean floor. They found that higher sediment concentrations carried microplastics farther, and finer sediment grains enhanced transport distances compared to coarser ones. The findings suggest that both the properties of the sediment flow and the shape and density of microplastic particles play important roles in determining where plastics end up in marine sediments.

2025 Environment International 13 citations
Article Tier 2

Non-buoyant microplastic settling velocity varies with biofilm growth and ambient water salinity

Researchers investigated how biofilms (thin layers of bacteria that grow on plastic surfaces), water salinity, and suspended clay affect how fast microplastics sink in water, finding that biofilm growth alone increased sinking speed by up to 130% within just hours. These findings show that current models predicting where microplastics end up in rivers and oceans are too simplistic, and that biological and chemical conditions must be factored in for accurate predictions.

2023 Communications Earth & Environment 72 citations
Article Tier 2

Settling velocities of microplastics with different shapes in sediment-water mixtures

Researchers studied how the shape of microplastic particles affects how quickly they sink in water containing suspended sediment. They found that fibers and films settle much more slowly than fragments and pellets, and that sediment in the water significantly slows the settling of all microplastic types. These findings are important for predicting where microplastics accumulate in lakes, rivers, and oceans.

2025 Environmental Pollution 14 citations
Article Tier 2

Physical Controls on Microplastic Retention in Estuarine Systems: Interactions Between Hydrodynamics, Stratification, Bathymetry, and Particle Properties

This review synthesizes how tidal patterns, river flow, water layering (stratification), estuary shape, and plastic particle properties together determine whether microplastics entering estuaries get trapped in sediments or flushed out to sea. Understanding these physical controls matters because estuaries are critical transition zones — nursery habitats for fish, shellfish, and migratory birds — and knowing where microplastics accumulate helps predict which species and communities face the highest exposure.

2026 American journal of student research.
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

Rapid flocculation and settling of positively buoyant microplastic and fine-grained sediment in natural seawater

Laboratory experiments showed that positively buoyant microplastics rapidly flocculated with fine-grained sediment in natural seawater, causing particles that would otherwise float to sink quickly. The finding has important implications for predicting microplastic fate in estuaries, where plastic-sediment aggregates may settle to the seafloor rather than dispersing.

2022 Marine Pollution Bulletin 49 citations
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

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

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

Study on the Mass Concentration Distributions of Marine Microplastics in Estuaries and Coastal Areas

Researchers characterized the mass concentration distribution of marine microplastics in estuarine and coastal environments, measuring spatial gradients between river mouths and open coastal waters and identifying estuaries as major transition zones for microplastic flux.

2025 Water 4 citations
Article Tier 2

Transport mechanisms and fate of microplastics in estuarine compartments: A review

This review analyzes how tides, river flow, density, biofouling, and sediment dynamics influence the transport and fate of microplastics in estuaries, identifying these transitional zones as both temporary sinks and conduits for plastic pollution.

2022 Marine Pollution Bulletin 189 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

Sediment-Water Interfaces as Traps and Sources of Microplastic Fragments and Microfibers─Insights from Stream Flume Experiments

Researchers used controlled stream flume experiments to study how microplastic fibers and fragments settle into riverbed sediments. They found that lower water flow speeds caused faster deposition, with the effect being strongest for fibers, and that traditional settling equations significantly underestimate how microplastics actually behave near the streambed. The findings improve our understanding of where and how microplastics accumulate in rivers.

2025 ACS ES&T Water 3 citations
Article Tier 2

Disentangling the retention preferences of estuarine suspended particulate matter for diverse microplastic types

Researchers used computer simulations to model how 16 different types of microplastics travel through the Yangtze River estuary in China. They found that lightweight, small-diameter fiber microplastics are most likely to clump together with suspended sediment, while heavier particles move more independently. The study reveals that turbid zones where river water meets the sea act as hotspots for microplastic accumulation.

2024 Environmental Pollution 5 citations
Article Tier 2

Modelling transport pathways of varying microplastics in an estuarine environment

Researchers modeled how microplastics of varying densities move through Galveston Bay, Texas, finding that settling velocity strongly influences retention time — neutrally buoyant particles flush out quickly while denser particles migrate westward and accumulate, highlighting the estuary's role in regional plastic transport.

2023 1 citations
Article Tier 2

Microplastics Settling in Turbid Water: Impacts of Sediments-Induced Flow Patterns on Particle Deposition Rates

Researchers studied how suspended natural sediments in turbid water affect the settling rates of microplastics. They found that the presence of fine clay and silt particles significantly increased microplastic deposition rates by creating downward flow patterns that drag the plastics along. The findings suggest that in naturally murky waters, microplastics may settle to the bottom faster than previously assumed, potentially concentrating pollution in sediment layers.

2025 Environmental Science & Technology 11 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

The Salinity Difference and Clay Mineral Types Affect the Distribution of Microplastics in the Seabed: New Evidence from the Western North Yellow Sea

Researchers examined how bottom seawater salinity gradients and clay mineral types influence microplastic distribution in surface sediments of the western North Yellow Sea, a semi-enclosed continental shelf area with complex current conditions. The study provides field-scale evidence that salinity differences and clay mineralogy jointly control MP settlement and distribution patterns beyond the laboratory conditions in which these effects were previously demonstrated.

2025 Water
Article Tier 2

Aggregation behavior of polyethylene microplastics in the nearshore environment: The role of particle size, environmental condition and turbulent flow

Researchers investigated how particle size, salinity, dissolved organic matter, and turbulent flow affect the aggregation behavior of polyethylene microplastics in nearshore water, finding that all factors influenced aggregation rates and aggregate structure. Understanding microplastic aggregation in estuarine environments is essential for predicting their sedimentation and biological uptake.

2023 The Science of The Total Environment 20 citations