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61,005 resultsShowing papers similar to High-Resolution Mapping of Japanese Microplastic and Macroplastic Emissions from the Land into the Sea
ClearAssessment of the sources and inflow processes of microplastics in the river environments of Japan
Researchers mapped microplastic concentrations across 29 Japanese rivers and found plastic particles present at 31 of 36 sampling sites. The concentrations were strongly linked to urbanization and population density, confirming that human activities in river basins are a major driver of freshwater microplastic pollution. The findings demonstrate that significant plastic fragmentation occurs before debris reaches the ocean, making rivers an important area for pollution monitoring.
Current Status and Issues of Microplastic Pollution Research
This Japanese review summarized microplastic research in river and ocean environments, including national estimates of plastic discharged from Japan's rivers to the sea and microplastic distribution in Tokyo Bay. The paper also reviewed current analytical methods and their limitations for measuring small microplastic particles.
Evaluation of Micro- Nanoplastic Generation Potential in Class a River Basins Considering Population Distribution and Meteorogical Conditions
Researchers developed a grid-based model to evaluate micro- and nanoplastic generation potential in Class A river basins across Japan, applying degradation models from accelerated aging tests to population distribution, UV radiation, and rainfall data, finding the highest per-area potential in the densely populated Tsurumi River basin.
Assessing small-scale freshwater microplastics pollution, land-use, source-to-sink conduits, and pollution risks: Perspectives from Japanese rivers polluted with microplastics
Researchers assessed microplastic pollution in four small-scale Japanese rivers flowing into the Sea of Japan and Seto Inland Sea. The study found that these small rivers were more heavily polluted than many larger rivers worldwide, with polyethylene, polypropylene, and polyester fibers dominating, suggesting that small-scale rivers are significant but often overlooked conduits transporting land-based microplastics to marine environments.
Microplastic volumes in Tokyo Bay
Researchers quantified microplastic volumes across multiple sites in Tokyo Bay, Japan, finding spatial variation linked to urban runoff and river inputs, with surface waters and sediments showing distinct accumulation patterns.
Occurrence and distribution of plastic particles (10–25,000 μm) and microfibers in the surface water of an urban river network in Japan
This study assessed the occurrence and distribution of plastic particles (10-25,000 micrometers) and microfibers in the surface water of an urban river network in Japan, finding that plastic abundance was closely tied to urban land use and proximity to discharge points.
Quantifying annual microplastic emissions of an urban catchment: Surface runoff vs wastewater sources
Researchers measured the total annual microplastic emissions from an urban river catchment in Japan and compared contributions from wastewater treatment plants versus surface runoff. They found that the catchment released about 269 tons of microplastics per year, with wastewater being the dominant source for smaller particles and surface runoff contributing more larger particles. The study provides one of the first comprehensive annual budgets of urban microplastic emissions, highlighting the scale of the problem.
An Integrated Assessmentof Microplastic Pollutionin Coastal Surface Water and Sediment of Japan
Researchers conducted an integrated assessment of microplastic pollution in coastal surface water and sediment around Japan, providing a comprehensive dataset that clarifies the extent of contamination in Japanese coastal areas previously lacking systematic monitoring data.
An integrated assessment of microplastic pollution in coastal surface water and sediment of Japan
Researchers conducted a comprehensive survey of microplastic pollution across 14 coastal locations around Japan from Hokkaido to Okinawa, measuring concentrations of 288.7 g/km2 in surface water and 1,185 kg/km2 in sediment and characterizing polymer types, shapes, and size distributions.
Survey on Microplastics and Macroscopic Floating Garbage in River, Coasts, and Estuary in the Eastern Part of Takamatsu City, Japan
Researchers surveyed microplastics and macroscopic floating litter in rivers, coasts, and estuaries in eastern Takamatsu City, Japan, finding PE and PP dominated microplastics in both river and coastal environments, and that plastic fragments, bags, and cigarette butts were the most common macro-litter items with distribution influenced by wind and wave conditions.
A Methodology to Characterize Riverine Macroplastic Emission Into the Ocean
This paper presents a standardized methodology for measuring and characterizing macroplastic emissions from rivers into the ocean, addressing a major data gap in global plastic budget estimates. Consistent measurement frameworks are essential for understanding how much plastic enters the ocean from land-based sources via rivers.
Comprehensive Understanding of Microplastics Inflow Off the Coast of Funabashi
Researchers conducted continuous monitoring of microplastic (MP) contamination in rivers, sewage, and coastal waters around Funabashi in Tokyo Bay, finding that MP number densities showed high temporal variability and a gradual decreasing trend, with upstream river sources driving contamination that diminished toward the sea as particles settled into bottom sediments, while sewage was also implicated as a contributor to marine MP pollution.
A local-to-global emissions inventory of macroplastic pollution.
This study developed a high-resolution global inventory of macroplastic pollution by distributing nationally reported waste management data down to sub-national and local scales, producing maps of plastic emission hotspots. The dataset is intended to support negotiations for a global plastics treaty by providing a data-driven baseline for identifying sources and prioritizing interventions.
Microplastic abundance in the semi-enclosed Osaka Bay, Japan
Researchers quantified microplastic abundance in the semi-enclosed Osaka Bay, Japan, finding elevated concentrations near river mouths and urban coastal zones, and characterizing dominant polymer types consistent with consumer plastics.
Microplastics in the sediments of small-scale Japanese rivers: Abundance and distribution, characterization, sources-to-sink, and ecological risks
Researchers characterized microplastic pollution in sediments of four small-scale Japanese rivers, finding widespread contamination and identifying polymer types and potential sources, highlighting that even small river systems serve as microplastic transport pathways.
Occurrence, distribution, and possible sources of microplastics in the surface river water in the Arakawa River watershed
Researchers investigated the occurrence, distribution, and potential sources of microplastics in surface river water along the Arakawa River watershed running through the Tokyo Metropolitan area, contributing to data on microplastic contamination in populated urban freshwater systems.
Microplastic pollution in sophisticated urban river systems: Combined influence of land-use types and physicochemical characteristics
This study assessed microplastic pollution across an urban river network in China, finding that land-use type and water physicochemical properties jointly influence microplastic distribution, with industrial and residential areas contributing highest loads.
Characteristics of Microplastics and Macro-sized Coastal Debris on the Beaches of the Eastern Takamatsu City, Japan
A beach survey in eastern Takamatsu, Japan found that the beach near a large urban river mouth had higher concentrations of both microplastics and macro-litter than a more remote beach, with polyethylene dominating at one site and polystyrene at the other. Most litter items were less than six months old, suggesting rapid accumulation from nearby sources rather than long-range ocean transport.
Underestimated land-to-sea microplastic emissions: The crucial role of rainfall events
Researchers investigated the emission characteristics and loads of microplastics transported into Masan Bay via the Samhocheon stream during a rainfall event using time-weighted sampling, finding microplastic abundances ranging from 4.60 to 118 particles per liter with an event mean concentration of 29.87 particles per liter. They found that microplastic concentrations peaked during early runoff and varied with rainfall intensity, with polypropylene and polyethylene accounting for approximately 60% of detected polymers.
Quantitative Analysis of Urban Microplastic Dissemination and Accumulation in Marine Ecosystems: Pathways, Processes, and Impacts
Researchers used water and sediment sampling across urban, riverine, and marine environments to quantify microplastic pathways from cities into marine ecosystems, finding the highest concentrations in urban areas linked to industrial activity and poor waste management. Polyethylene, polypropylene, and PET were the most common polymer types, with seasonal peaks in concentration tracking periods of high rainfall and urban runoff.
Point-source microplastic input to the river and coastal zone via wastewater treatment facilities: a case study from a tropical mega-city
Point-source inputs of microplastics from a specific industrial or municipal source were quantified in both a river and the adjacent coastal zone. The study links land-based pollution sources to downstream and coastal microplastic concentrations, supporting targeted source-control interventions.
A proxy-based approach to predict spatially resolved emissions of macro- and microplastic to the environment
Using land-use statistics, traffic data, and wastewater infrastructure as proxies, researchers created high-resolution maps of microplastic and macroplastic emissions across Switzerland at the regional level. The approach reveals that plastic pollution is concentrated near urban and high-traffic areas but varies substantially by polymer type and emission source.
Estimation of macroplastic yield from river basin to coastal area: A case study of the Klang River, Malaysia
Researchers studied macroplastic distribution along a 20-kilometer stretch of the highly polluted Klang River in Malaysia and developed a method to estimate total plastic yield from the river basin to the coast. They found 240 items of weathered macroplastics and characterized their composition and degradation patterns. The study provides a practical protocol for quantifying how much plastic pollution flows from rivers into coastal marine environments.
Rapid Sampling of Suspended and Floating Microplastics in Challenging Riverine and Coastal Water Environments in Japan
Two newly developed compact sampling devices (Albatross Mark 5 and 6) collected microplastic samples from Japanese rivers and coastal waters in just 3 minutes compared to 10-60 minutes with conventional nets, while producing comparable concentration measurements. Polyethylene and polypropylene dominated, and particles became smaller from riverine to coastal environments.