Polytetrafluoroethylene microplastic properties, pollution, toxicity and analysis: a review

The pollution of microplastics in sediments: The ecological risk assessment and pollution source analysis

Microplastic pollution in oyster bed ecosystems: An assessment of the northern shores of the United Arab Emirates

Pilot study on microplastics in the Suquía River basin: Impact of city run-off and wastewater treatment plant discharges in the mid-2010s

The pollution of microplastics in sediments of the Yangtze River Basin: Occurrence, distribution characteristics, and basin-scale multilevel ecological risk assessment.

RETRACTED: Microplastic pollution in intertidal sediments along the coastline of China

Microplastic pollution in a stormwater floating treatment wetland: Detection of tyre particles in sediment

In recent years, microplastics (MPs) in the environment has become a topic of increasing concern. In this study, typical urban lakes, such as Yushan Lake and Nanhu Lake in Maanshan City, were selected to study the physical morphology and spatial distribution characteristics of MPs in sediments in spring and summer and to explore the sources of MPs in the lakes. On average, MPs in sediments occurred with a content of (0.0284±0.0597) g·kg-1 and abundance of (278.9±529.1) n·kg-1 in spring, and (0.0317±0.0778) g·kg-1 and (277.1±395.6) n·kg-1 in summer, respectively. Using a paired sample T-test, it was found that there was no significant correlation difference between the content (N=22, t=-0.269, P=0.791) and the abundance (N=22, t=0.035, P=0.973) of MPs in the spring and summer sediments. Regarding shape, the MPs in the sediments in the study area were divided into three types:fiber, film, and particle, accounting for 52.9%, 28.9%, and 18.2%, respectively. Size-fraction analysis indicated MPs<1 mm made up the majority, accounting for 83.9% of the total number. It was found that the MPs were mainly polyethylene (PE) and polypropylene (PP) polymers with seriously weathered surfaces. The sediments, which were adjacent either to land with a large stream of people and vehicles or to areas with frequent watersports, had notably high abundance of MPs, revealing the close correlation between the spatial distribution of MPs in lake sediments and human activities. It is thought that atmospheric precipitation (fiber), stormwater, washing of clothes (fiber), degradation of large plastics in the lake, and fishing activities (fishing nets, foam) are the main sources of MPs in lake sediments.

Microplastics (MPs) in sediments from the complex lagoon-channel of Bizerte were investigated, for the first time, to evaluate the occurrence and abundance of MPs in Tunisia. After density separation in saline solution, MPs were counted by a stereomicroscope. The number of MPs was at the range of 3–18 items/g sediment (3000–18,000 items/kg dry sediment) and the most contaminated site was of Menzel Abderrahmane (MA) followed by Carrier Bay (CB), Menzel Jemil (MJ) and Channel of Bizerte (C). The MPs gathered during the survey varied in size from 0.3 to 5 mm, and appear in a variety of shapes and colours. The dominant shape was fibre (88.88% in MA, 91.00% in CB, 82.35% in C and 21.05% in MJ). The rest of MPs are fragments whilst no micro beads were found. Colours are clear, white, blue, green, red and black. Cities discharges, fishing activity and industrial production sites are the most likely sources of MPs. This first work provides original data on the presence of MPs that determines their bioavailability to organisms as seafood, and then possibly transfers of to human. The high MP concentrations registered in the complex lagoon-channel of Bizerte suggest that this site is a hotspot for MP pollution and there is an urgency to understand their origins and effects on marine life. The results will provide useful background information for further investigations.

Microplastics (<5mm) were extracted from sediment cores collected in Japan, Thailand, Malaysia, and South Africa by density separation after hydrogen peroxide treatment to remove biofilms were and identified using FTIR. Carbonyl and vinyl indices were used to avoid counting biopolymers as plastics. Microplastics composed of variety of polymers, including polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethyleneterphthalates (PET), polyethylene-polypropylene copolymer (PEP), and polyacrylates (PAK), were identified in the sediment. We measured microplastics between 315µm and 5mm, most of which were in the range 315µm-1mm. The abundance of microplastics in surface sediment varied from 100 pieces/kg-dry sediment in a core collected in the Gulf of Thailand to 1900 pieces/kg-dry sediment in a core collected in a canal in Tokyo Bay. A far higher stock of PE and PP composed microplastics in sediment compared with surface water samples collected in a canal in Tokyo Bay suggests that sediment is an important sink for microplastics. In dated sediment cores from Japan, microplastic pollution started in 1950s, and their abundance increased markedly toward the surface layer (i.e., 2000s). In all sediment cores from Japan, Thailand, Malaysia, and South Africa, the abundance of microplastics increased toward the surface, suggesting the global occurrence of and an increase in microplastic pollution over time.

Microplastics (MPs) are globally recognized as an emerging environmental threat, particularly in the aquatic environment. This study presents baseline data on the occurrence and distribution of MPs in sediments and surface water of major rivers in southwestern Nigeria. Microplastics were extracted by density separation and polymer identification using Fourier transformed infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR). The abundance of MPs in surface sediment and water samples across all locations ranged from 12.82 to 22.90 particle/kg dw and 6.71 to 17.12 particle/L during the dry season and 5.69 to 14.38 particle/kg dw and 12.41 to 22.73 particle/L during the wet season, respectively. On average, fiber constituted the highest percentage of MP in sediments (71%) and water (67%) while foam accounted for the lowest values of 0.6% and 1.7%, respectively. Polypropylene(PP) and polyethylene (PE) were the main MPs across all locations based on Fourier transform infrared spectroscopy (FTIR). MPs of size < 1mm were the most abundant (≥ 55%) on average in both water and sediments. The study identified run-off from human activities and industrial wastewater as potential sources of MP exposure based on positive matrix factorization. The study suggests assessing the impact of different land-use activities on MPs occurrence and distribution in addition to quantifying MPs in seafood as a way forward in food safety management systems for further studies. This study confirmed the occurrence and widespread distribution of MPs in surface water and sediments and provides a database on MP pollution in Nigeria.

Microplastics pollution with heavy metals in the aquaculture zone of the Chao Phraya River Estuary, Thailand

Rivers are major sources of marine microplastics. To investigate the influence of building use on river microplastic pollution, this study focused on the Chongqing section of the main stream of the Yangtze River. Surface water and sediment microplastic samples were collected and analyzed alongside building use data to explore the relationship between microplastic abundance and building use at different spatial scales. The results showed that: (1) The abundance of microplastics in surface water and sediment in the Chongqing section of the Yangtze River exhibited an inverse distribution pattern. In the upper reaches, the central urban area of Chongqing showed significantly higher microplastic levels in surface water (6,811 ± 3,101 n/m ³) compared to the lower reaches, confirming the direct input effect of high-intensity human activities. The accumulation of microplastics in sediment was greater in the northeastern section of Chongqing compared to the lower reaches (89.6 ± 69 vs. 45.4 ± 28 n/kg), indicating a hydrodynamic-driven sedimentation lag effect. (2) The influence of building use on microplastic abundance in surface water was significantly scale-dependent. Industrial buildings within a 2 km buffer zone explained up to 61.16% of the observed variance, suggesting cross-medium migration through atmospheric sedimentation and sewage pipe network. (3) Compared to land use types, building uses dominate the abundance distribution of microplastics in surface water at larger buffer radius (1–2 km), indicating that high-intensity human activities have a greater impact on spatial differentiation of microplastic pollution. It is recommended to implement hierarchical control measures along the Chongqing section of the Yangtze River. A 2-km ecological buffer zone is set up in industrial agglomeration areas to strictly supervise wastewater discharge from plastic products enterprises. Rainwater bioretention facilities are built within 1 km of densely populated areas to intercept microplastics from domestic sources, such as laundry fibers. This study explores the mechanism by which building use affects river microplastic pollution, providing valuable insights for microplastics control in large river basins worldwide.

Fishery activities are an important source of microplastic pollution in coastal areas but have received little attention. The Beibu Gulf, a traditional fishing ground of China and the China-Indo Peninsula, was selected in this study, and the focus was on the impacts of fishery activities on the horizontal distribution of microplastics in sediment. The results showed that the dominant contaminants (polypropylene fibers and polyethylene fibers) might originate from the abrasion of fishing gear and contributed to 61.6% of the total abundance of microplastics in surface sediment. The abundance of polypropylene fibers and polyethylene fibers exhibited a strong correlation (R2 = 0.8586, p = 0.015) with values of fishery yields of different districts, which highlighted the effects of different fishery activities on microplastic contamination in marine sediment. Microplastics could be "hidden" in deep sediment to a depth of 60 cm. The estimated storage of microplastics in deep sediment (185 tons) was 5 times that in surface sediment. The assessment of microplastic storage worldwide might be underestimated because most previous studies only examined surface sediment. The abundance distribution and size distribution of microplastics in the sediment core suggested long-term burial of microplastics in deep sediment. Bioturbation might be responsible for the vertical transport of microplastics, leading to "fresh microplastics" preservation in "old sediment".

The sustainable management of microplastics pollution in sediments from China: Promulgating relevant laws and implementing targeted management

IntroductionThe Gulf of Trieste is prone to the accumulation of various pollutants and microplastics due to its geomorphological and hydrological characteristics. However, the distribution and sources of microplastics in this semi-enclosed area are poorly studied. The aim of our study was to determine the distribution and chemical composition of MP particles in the sediments of the Gulf of Trieste.MethodsIn this study, we collected 24 surface sediment samples using a Van Veen grab. Microplastics were extracted by density separation using NaCl. The size, shape, and color of the extracted microplastics were determined using an optical microscope, and the composition of the polymers was determined by Fourier transform infrared spectroscopy.Results and discussionThe highest concentrations of up to 125 microplastic particles per 100 g dry sediment were found in coastal areas. Concentrations in the open sea were much lower, with an average of 3 particles per 100 g of sediment. Most of the microplastic was fibrous, made of polypropylene, 100–300 µm in size, and blue. This is the first study showing that microplastics are present in the sediments of the south-eastern part of the Gulf of Trieste. The findings suggest that microplastics exhibit a tendency to be retained within the sediment, leading to their accumulation primarily in a narrow coastal area rather than dispersing offshore. Our results will contribute to a better knowledge of the distribution and possible sources of plastics and microplastics in the Gulf of Trieste and even beyond in similar semi-enclosed marine areas.