Papers

61,005 results
|
Article Tier 2

Microplastic pollution in streams spanning an urbanisation gradient

Researchers sampled microplastics in small streams across an urbanization gradient and found contamination at all sites, with concentrations comparable to those in larger rivers and lakes. Fragments and small particles between 63 and 500 micrometers were the most common forms detected. Surprisingly, catchment-scale factors like population density and stormwater overflows did not predict microplastic levels well, suggesting that local-scale sources may be more important for pollution in small streams.

2019 Environmental Pollution 218 citations
Article Tier 2

Effects of urbanisation and a wastewater treatment plant on microplastic densities along a subtropical river system

Researchers quantified microplastic pollution in sediments along a subtropical river system in southern Africa and examined how urbanization and wastewater treatment affect contamination levels. They found that microplastic densities were highest near urban areas and downstream of wastewater treatment plants. The study suggests that urban development and inadequate wastewater infrastructure are key drivers of freshwater microplastic pollution in the region.

2021 Environmental Science and Pollution Research 63 citations
Article Tier 2

Profiling microplastics in a forgotten river system in Southern Africa

Researchers profiled microplastic distribution across the Nyl, Mogalakwena, and Limpopo Rivers in South Africa over multiple seasons. They found that seasons with reduced water flow had significantly higher microplastic concentrations in both water and sediment, while high-flow seasons produced a more evenly distributed but lower overall abundance. The study also detected microplastics in benthic macroinvertebrates throughout the river system, indicating the particles have become bioavailable in the food web.

2025 Environmental Monitoring and Assessment 5 citations
Article Tier 2

Distinct microplastic patterns in the sediment and biota of an urban stream

Researchers found distinct microplastic contamination patterns between sediments and aquatic biota in an urban stream, with sediments accumulating more particles while biota showed selective uptake based on particle size and shape, highlighting the complex dynamics of microplastic distribution in urban freshwater systems.

2022 The Science of The Total Environment 35 citations
Article Tier 2

Contrasting Microplastic Characteristics in Macroinvertebrates from Two Independent but Adjacent Rivers in Kruger National Park, South Africa

Researchers investigated microplastics in benthic macroinvertebrates — including filter feeders, predators, and grazers — from the Olifants and Sabie rivers in Kruger National Park, finding an average of 1.0 MPs per organism and significantly higher burdens in filter feeders (8.8/organism) and predators (8.5/organism) than in grazers.

2025 Water
Article Tier 2

Microplastics in freshwater environment: the first evaluation in sediment of the Vaal River, South Africa

Researchers conducted the first assessment of microplastic pollution in the Vaal River, South Africa, finding microplastics in 100% of sediment samples at an average of 463 particles per kilogram, with polyethylene and polypropylene as the dominant polymer types.

2022 Heliyon 39 citations
Article Tier 2

Microplastic abundance, distribution, and diversity in water and sediments along a subtropical river system

Researchers investigated microplastic abundance in water and sediments along a subtropical river system in South Africa, finding widespread contamination with fibers as the dominant shape and polyethylene as the most common polymer type.

2023 Environmental Science and Pollution Research 39 citations
Article Tier 2

Occurrence and distribution of microplastics in functionally delineated hydraulic zones in selected rivers, Eastern Cape, South Africa

Researchers mapped microplastic distribution across different flow zones in two urban rivers in South Africa, finding that slow-flowing pools and backwaters accumulate significantly more settled microplastics than fast-flowing areas. Polyethylene and polypropylene fibers and fragments were the most common types found. The study helps explain where microplastics concentrate in rivers, which is important for understanding exposure risks at drinking water intake points downstream.

2025 Environmental Pollution 6 citations
Article Tier 2

Microplastics in freshwater sediments: Effects on benthic invertebrate communities and ecosystem functioning assessed in artificial streams

Researchers tested the effects of polyethylene microplastics on freshwater invertebrate communities in artificial streams using environmentally relevant concentrations. They found that microplastics significantly reduced the abundance of deposit-feeding and grazing organisms by 31-50%, with chironomids and mayflies showing the highest ingestion of plastic particles.

2021 The Science of The Total Environment 74 citations
Article Tier 2

The effect of urban point source contamination on microplastic levels in water and organisms in a cold‐water stream

Microplastic concentrations in water, macroinvertebrates, and trout in a Wisconsin stream increased significantly downstream of stormwater outfalls and a wastewater plant. The study demonstrates that point sources of pollution drive measurable increases in microplastic contamination in freshwater food webs.

2019 Limnology and Oceanography Letters 48 citations
Article Tier 2

Comparative Assessment of Microplastics in Surface Waters and Sediments of the Vaal River, South Africa: Abundance, Composition, and Sources

Microplastics were extracted from surface water and sediment samples in the Vaal River in Johannesburg, South Africa, finding average abundances of 0.61 particles per cubic meter in water and 460 particles per kilogram in dry sediment. Fragments and fibers under 2 mm dominated, with polyethylene and polypropylene as the most common polymers.

2022 Environmental Toxicology and Chemistry 49 citations
Article Tier 2

Morphological and Chemical Characteristics of Microplastics in Surface Water of the Vaal River, South Africa

Researchers surveyed 60 kilometers of South Africa's Vaal River and found microplastics in every surface water sample, with fragments and fibers making up 81% of particles and common packaging plastics (HDPE, PP, LDPE) as the main polymers. This is one of the first detailed microplastic assessments of a major South African freshwater system, establishing a baseline for future pollution monitoring.

2024 Environmental Processes 28 citations
Article Tier 2

Fluvial Concentrations of Microplastics in a Suburban Micro-Watershed: Sampling Methodology and Analysis

Researchers designed a low-cost sampling station to collect and quantify microplastics in a shallow suburban stream in South Carolina. They found that microplastic abundance increased from the top of the watershed to the bottom, rising from about 269 to 715 particles per 10 cubic meters of surface water. Fibers were the dominant type, and the study highlights the need for standardized sampling methods for small freshwater streams.

2024 Environmental Engineering Science 2 citations
Article Tier 2

Influence of Urbanization and Seasonality on Microplastics in a Small Brazilian Inland Stream

Researchers sampled a small Brazilian inland stream upstream and downstream of an urban center during dry and rainy seasons, finding urbanization significantly increased microplastic abundance from 1.7 to 2.6 particles per liter during the dry season, while rainfall effects were less consistent.

2025 Microplastics
Article Tier 2

Microplastic accumulation in benthic macroinvertebrates is widespread, regardless of the river ecological status

A broad survey of freshwater benthic macroinvertebrates across multiple rivers found that microplastic accumulation was widespread regardless of local urban development levels, suggesting that factors beyond proximity to urban areas—such as river hydrology and upstream sources—drive MP exposure in freshwater invertebrates.

2025 Hydrobiologia 3 citations
Article Tier 2

Relationship between selected hydrodynamic indices and microplastic distributions across mesohabitats in urban rivers, Eastern Cape, South Africa

Researchers investigated how hydrodynamic indices — Froude number, Reynolds number, and shear velocity — shape the spatial and seasonal distribution of microplastics across different hydraulic zones in three subtropical urban rivers in South Africa's Eastern Cape Province. The study found that hydraulic conditions significantly governed microplastic retention in pools and backwaters versus riffles and runs, with seasonal variation between dry and wet periods.

2025 The Science of The Total Environment
Article Tier 2

Effects of anthropogenic activities on microplastics in deposit-feeders (Diptera: Chironomidae) in an urban river of Taiwan

Researchers quantified microplastic abundance and types in midge larvae (Chironomidae) from an urban river and found that multiple anthropogenic activities including industrial discharge, agriculture, and residential runoff were associated with elevated microplastic levels in these freshwater deposit-feeders.

2021 Scientific Reports 38 citations
Article Tier 2

Macroinvertebrate colonisation of macroplastic litter in minimally disturbed river sites, Eastern Cape, South Africa

This South African study looked at whether macroplastic litter in streams could be colonized by aquatic invertebrates in the same way that natural materials like leaves and rocks are. Over six months, invertebrates colonized plastic substrates at similar overall levels to natural ones, but in slow-moving pool habitats, natural substrates supported greater species diversity. The dominant invertebrate species were present across all substrate types throughout the study. The findings suggest that while plastic in streams does not entirely replace natural habitat, it may reduce biodiversity in certain flow conditions — with potential cascading effects on freshwater ecosystems.

2025 Aquatic Ecology 1 citations
Article Tier 2

Microplastics prevalence in water, sediment and two economically important species of fish in an urban riverine system in Ghana

Microplastics were detected in water, sediment, and two commercially important fish species from an urban river system in Ghana, with fiber being the dominant type across all matrices. The study represents one of the first assessments of freshwater microplastic contamination in West Africa and highlights urban river systems as major pathways for plastic transport.

2022 PLoS ONE 65 citations
Article Tier 2

Assessing microplastic characteristics and abundance in the sediment and surface water of the Diep River, Western Cape, South Africa

Researchers investigated microplastic pollution in the Diep River in South Africa's Western Cape, analyzing both water and sediment samples from five locations. Fibers were the most dominant microplastic shape at all sites, with polyethylene and polystyrene being the most common polymer types. The study found that tourist and recreational areas had higher microplastic contamination than non-tourist areas.

2025 Environmental Pollution 5 citations
Article Tier 2

Microplastic pollution differences in freshwater river according to stream order: Insights from spatial distribution, annual load, and ecological assessment

Researchers compared microplastic pollution levels in a freshwater river across different land-use zones, finding higher concentrations near urban and agricultural areas than in forested regions. Fiber-type microplastics were predominant across all sampling locations.

2024 Journal of Environmental Management 5 citations
Article Tier 2

The Role of Landscape Configuration, Season, and Distance from Contaminant Sources on the Degradation of Stream Water Quality in Urban Catchments

A study of a Portuguese river basin found that landscape configuration and proximity to pollution point sources both affect stream macroinvertebrate communities. Macroinvertebrates are sensitive to microplastic pollution, and their decline in contaminated streams can indicate broader ecosystem degradation.

2019 Water 38 citations
Article Tier 2

Benthic macroinvertebrates and microplastic contamination in contrasting water quality environments of the Middle Tietê River basin (São Paulo, Brazil)

Researchers compared microplastic contamination in benthic invertebrates and sediments between a heavily polluted urban river and a cleaner tributary in São Paulo, Brazil. Higher microplastic concentrations were found near urban areas, confirming that human activity drives plastic accumulation in freshwater ecosystems.

2023 LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas)
Article Tier 2

Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa

Researchers measured microplastic levels in sediment, surface water, and beach sand across five estuaries near Durban, South Africa, finding that an urban harbor area (Bayhead) had by far the highest concentrations and that plastic types shifted from fragments near the city to fiber dominance in more distant estuaries, confirming estuaries as conduits for terrestrial plastic entering the ocean.

2015 Marine Pollution Bulletin 282 citations