Microplastic Fibers Research Articles

Methylmercury sorption to polyethylene terephthalate (PET) fibers and relevance to environmental exposure

Abstract Considerable amounts of polyethylene terephthalate (PET) microplastic fibers are released into the environment by the laundering of polyester clothing. Microplastic fibers can be ingested by organisms in the environment. Therefore, it has been suggested that microplastic fibers act as vectors for adsorbed contaminants, which are subsequently desorbed in the gut of the organism. We undertook sorption isotherm experiments at pH 6, 7, and 8 to quantify the sorption of methylmercury (MeHg) to PET fibers. Sorption isotherms were fit to Langmuir, Freundlich, and Brunauer–Emmett–Teller models. Sorption decreased with increasing pH, which can be explained by physisorption on the negatively charged PET surfaces and the greater presence of neutral or negatively charged MeHg species at higher pH. We used the parameters obtained by the model fits to predict the likely concentration of MeHg on PET microplastic fibers in aquatic ecosystems with environmentally realistic MeHg concentrations. We calculated MeHg concentrations on PET microplastic fibers to be four orders of magnitude lower than previously observed concentrations of MeHg in seston (suspended particles comprising algae and bacteria) at the base of the aquatic food web. The results indicate that the presence of PET microplastic fibers in the environment do not elevate the MeHg exposure to organisms that ingest fibers in the environment.

Research on the PFAS release and migration behavior of multi-layer outdoor jacket fabrics.

Perfluoroalkyl and poly-fluoroalkyl substances (PFAS) release from textiles is a source of human exposure, but the mechanisms behind this release remain insufficiently studied. This research investigates the release and transport mechanisms of PFAS in outdoor jacket fabrics treated with a short side-chain fluorinated polymers (C6F13-SFPs) for durable water repellency (DWR). PA-based and PET-based fabrics were exposed to outdoor conditions and subjected to accelerated aging, followed by abrasion, washing, and drying experiments to simulate wear and degradation. The fabrics were analyzed for total fluorine (TF) content, PFAS composition, and microplastic fibers (MFs) release. Photocatalytic oxidation was applied to fabric extracts to assess the transformation of PFAS precursors. The results show that aging causes a reduction in TF content and an increase in PFAS migration to inner fabric layers, particularly perfluoroalkyl acid (PFAA) and n:2 fluorotelomer alcohol (FTOH). Extended washing cycles further elevated fluorine release and MF shedding, with significant fluorine detected in the wash effluents and MFs. In summary, PFAS in outdoor jackets after use exceed regulatory limits and are hazardous to the environment. Therefore, setting limits for only a few PFAS is inadequate to assess release hazards. Future efforts should revise regulations based on release pathways, assess toxicity, and develop better prevention technologies.

Microplastics in freshwaters: Comparing effects of particle properties and an invertebrate consumer on microbial communities and ecosystem functions.

The effects of microplastic (MP) accumulation in freshwaters on organisms and ecosystem functions are poorly understood, as are the roles of MP particle properties in regulating these effects. In freshwater microcosms, we quantified variation in microbial communities and ecosystem functions and compared effects of MP concentration (0, 1000, 50000 particles/kgsediment), shape (sphere, fragment, fibre), and polymer (polyethylene, polyethylene terephthalate, polypropylene, polystyrene) with those of a model invertebrate consumer (Chironomus riparius). We detected multiple effects of specific MP properties, especially associated with MP fragments and fibres, and the polymer polypropylene. These effects included increases in microbial abundance, consumer biomass and ecosystem respiration, as well as decreases in microbial enzyme activity and water chlorophyll-a. MP presence was also associated with increased relative abundance of microbial taxa reported to degrade plastics. However, consumer presence mostly had stronger effects (effect sizes ranging from ± 11 -313 %) than MP exposure (effect sizes ranging from ± 1-89 %) on microbial communities and ecosystem functions. Furthermore, several MP effects were only detected when chironomid consumers were absent. Overall, our findings suggest that MP effects on microbes and ecosystem functions are often relatively small and variable, depending on particle properties and consumer presence. Nevertheless, the number of MP effects detected highlights the need for further investigations of interactions between MPs and other environmental drivers, to more thoroughly assess the risks of MP pollution for freshwater ecosystems.

Assessment of potential ecological risk for microplastics in freshwater ecosystems.

Microplastics (MPs) are one of the most widespread environmental pollutants, but their risk assessment to freshwater ecosystems has not been clearly investigated. Risk assessment has been constrained by the absence of MP concentration in some environment, the diverse types and shapes of MPs, and limitations of polystyrene (PS)-biased toxicity studies. This study examined exposure to MPs in rivers and lakes worldwide, including China (the Three Gorges Dam & Yangtze River (TGD & YR) and the lakes of Wuhan city (WL)), Vietnam (seven lakes of Da Nang city (7UL)), Europe (the Rhine River (RR)), Finland (Kallavesi Lake (KL)), Argentina (nine lakes in the Patagonia region (9LP)), Brazil (Guaiba Lake (GL)), and South Korea (Nakdong River (NR), Han River (HR), and Anyang Stream (AS)), and assessed the risks to aquatic ecosystems based on the toxicity information and morphology of MPs. We also examine the limitations of the traditional risk quotient (RQ)-based risk assessment method for PS-biased toxicity studies. Potential ecological risks were assessed using pollution load index (PLI) and potential ecological risk index (PERI) considering the hazard scores of MP types. RQ was approximately 10-6 to 10-4, indicating negligible risk to aquatic organisms. In contrast, the calculated PLI (> 30: extreme danger) and PERI (> 1200: extreme danger) values suggest that MPs represent serious ecological threats at all the study locations. Furthermore, principal component analysis (PCA) indicated that MP fibers and fragments have a significant impact on the risks for freshwater systems. These MP morphologies derive from surrounding fishing and agricultural activities, and household and clothing industries. The areas surrounding these rivers and lakes are expected to become more densely populated, potentially leading to increased MP emissions and higher risks, suggesting a need to expand wastewater treatment facilities, reduce consumption of single-use plastics, and raise societal awareness of waste plastics.

Chronic effects of irregular and fibril microplastics on Artemia franciscana in a benthic environment: Size and shape-dependent toxicity

Marine ecosystems are contaminated by plastic products, particularly microplastics (MPs), which settle on the seafloor and affect benthic organisms. This study explores the toxicity of irregular fibril-shaped MPs of various sizes and lengths on Artemia franciscana. We exposed juvenile A. franciscana to irregular-shaped MPs of three sizes, small (<20 μm), medium (40–70 μm), and large (>120 μm), and MP fibers of two length categories, short (200–300 μm) and long (3 mm), in a sand-layered benthic system. The concentrations of the MPs were maintained at 0.05–20 mg/L, and the study was conducted over a 28-d of chronic period. Among all the MPs considered in this study, the small and short MPs exerted the most severe effects (causing mortality, growth inhibition, gut damage, alterations in movement, and a decrease in positive phototaxis). Our study highlights the importance of considering the morphological characteristics of MPs for analyzing their toxicity to aquatic eco-receptors.

Assessing the interaction between 4-methylbenzylidene camphor and microplastic fibers in aquatic environments: Adsorption kinetics and mechanisms

Wastewater treatment plants play a crucial role in managing environmental pollutants, but they often release persistent contaminants like synthetic microplastic fibers (MPFs) into ecosystems. These microplastics, mainly from the textile industry and domestic washing of synthetic fabrics, are a major type of microplastic found in aquatic environments. Some harmful chemicals have an affinity for these microplastics, making them vectors for contaminants. This study investigates the adsorption of 4-methylbenzylidene camphor (4-MBC), an organic UV filter, onto microplastic fibers from two different sources. Batch experiments conducted at room temperature (25 °C) under laboratory conditions assessed the adsorption kinetics and mechanisms. Morphological and visual characterization of the microplastic fibers was done using optical microscopy and scanning electron microscopy (SEM), revealing diverse shapes, types, and colors. Physico-chemical properties were confirmed through thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). The data matched well with the PSO kinetic model and Langmuir isotherm, indicating monolayer chemisorption with equilibrium achieved within 24 h. The adsorption mechanisms involved electrostatic attraction, hydrogen bonding, and π-π interactions. Both types of microplastic fibers exhibited a tendency to adsorb 4-MBC, indicating the significance of this research in understanding the interactions between this compound and various fiber types emphasizing the need for further research under the different environmental conditions.

Fibrous foes: First report on insidious microplastic contamination in dietary fiber supplements

Regular consumption of health supplements to balance dietary intake has gained popularity worldwide. One such supplement that has gained popularity among consumers is dietary fibers. Microplastic (MPs) contamination in various food products is being reported worldwide. However, there is a paucity of understanding of the occurrence of MPs in dietary supplements. This study addresses this gap by investigating the degree of MPs contamination in dietary fiber supplements. Nine commonly consumed (powder and gummy-based) over-the-counter dietary fiber supplements in Australia were tested in this study. Microscopic examination revealed the presence of MPs fibers and fragments in all the tested products. Further categorization showed that MPs particles were of various colours, including black, blue, red, green, and white. The order of polymer abundance was Polyamide > Polydiallyl Phthalate > polyethylene polypropylene diene > Polyurethane = Polyethylene terephthalate > Polyethylene = Ethylene acrylic acid copolymer. Among the supplements, powder-based samples had higher MPs (at the adult dosage suggested by the manufacturer) than gummy-based product. The average predicted ingestion of microplastics from these supplements (all nine samples) was 5.89 ± 2.89 particles day−1. The dietary exposure for children and adults ranged from 0.1–0.48 and 0.18–4.08 particles day−1, respectively. Based on the microplastic contamination factor (MCF), among the nine samples tested, 69.81% exhibited a moderate level, while 20.76% showed a significant level of microplastic contamination. The polymer risk index (pRi) indicates products with very high and high-risk categories. The possible sources of MPs contamination in the products were studied. To our knowledge, this is the first study to record and quantify the presence of MPs in dietary fiber supplements, which is a direct source of MPs exposure to humans via., ingestion.

FLEXPART version 11: improved accuracy, efficiency, and flexibility

Abstract. Numerical methods and simulation codes are essential for the advancement of our understanding of complex atmospheric processes. As technology and computer hardware continue to evolve, the development of sophisticated code is vital for accurate and efficient simulations. In this paper, we present the recent advancements made in the FLEXible PARTicle dispersion model (FLEXPART), a Lagrangian particle dispersion model, which has been used in a wide range of atmospheric transport studies over the past 3 decades, extending from tracing radionuclides from the Fukushima nuclear disaster, to inverse modelling of greenhouse gases, and to the study of atmospheric moisture cycles. This version of FLEXPART includes notable improvements in accuracy and computational efficiency. (1) By leveraging the native vertical coordinates of European Centre for Medium Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS) instead of interpolating to terrain-following coordinates, we achieved an improvement in trajectory accuracy, leading to a ∼8 %–10 % reduction in conservation errors for quasi-conservative quantities like potential vorticity. (2) The shape of aerosol particles is now accounted for in the gravitational settling and dry-deposition calculation, increasing the simulation accuracy for non-spherical aerosol particles such as microplastic fibres. (3) Wet deposition has been improved by the introduction of a new below-cloud scheme, by a new cloud identification scheme, and by improving the interpolation of precipitation. (4) Functionality from a separate version of FLEXPART, the FLEXPART CTM (chemical transport model), is implemented, which includes linear chemical reactions. Additionally, the incorporation of Open Multi-Processing parallelisation makes the model better suited for handling large input data. Furthermore, we introduced novel methods for the input and output of particle properties and distributions. Users now have the option to run FLEXPART with more flexible particle input data, providing greater adaptability for specific research scenarios (e.g. effective backward simulations corresponding to satellite retrievals). Finally, a new user manual (https://flexpart.img.univie.ac.at/docs/, last access: 11 September 2024) and restructuring of the source code into modules will serve as a basis for further development.

Experimental Visualization and Modeling of the Transport Behaviors of Monofilament Microplastic Fibers Through an Idealized Porous Media

AbstractMicroplastic fibers (MPF) are the largest fraction of microplastics in the environment by mass. The endpoints of these contaminants' movement is generally known at large‐scale (i.e., their origins and where they end up), but the mechanics of how they get to those sinks remains poorly understood. The objective of this work was to improve understanding of the mechanisms driving MPF migration through terrestrial systems by directly imaging their motion through idealized representations of porous media. Monofilament line with 0.3 mm diameter was passed through a bench‐scale, pseudo‐2d flow cell to capture trajectories of MPFs of three different lengths and trajectories of passive micro‐bead tracers were also captured. Video processing and automated image analysis converted the video of the experiments into a database of trajectories, allowing comparison of the experimental data to various numerical models. Simple advection‐dispersion models were adequate for modeling the passive tracer but did not provide a good description of MPF transport. A physics‐based, distributed model was able to generate realistic trajectories through the domain, but the speeds of the fibers in the initial simulation were too fast, despite working well for the passive tracer. Adding a delay (waiting time) process resulted in good description of the trajectories and travel times. The specifics of the delay process could not be deduced from these experiments, but its overall impact on transport provides mechanistic insights. These direct observation of the trajectories and speeds of MPFs moving through porous media show that MPFs likely have strong interactions with their surroundings.

Sources Affecting Microplastic Contamination in Mountain Lakes in Tatra National Park

The global atmospheric transport of microplastics (MPs) plays a crucial role in the contamination of remote, especially higher-elevation, environments. Precipitation is considered the main source of MP pollution. Meanwhile, plastic waste generated from, for example, tourism activities can be a local source of MP pollution. In this study, we specify which of the mentioned sources of MP, global or local, have a higher impact on the pollution level in the high-elevation oligotrophic lakes of Tatra National Park in Poland. Due to its unique natural value, it is listed by UNESCO as an international biosphere reserve and meets the criteria for Natura 2000 areas. We comprehensively analyzed the morphometric and anthropogenic features of 11 lakes in terms of the contamination level, color, shape, and polymer type of the MPs found in the surface waters. MP fibers were found to be present in all studied lakes, with contamination ranging from 25 to 179 items/m3. Polypropylene, polyethylene terephthalate, and natural or semi-natural cellulose fibers—black or red in color with a length of 0.2–1.0 mm—predominated, which corresponds with other studies conducted on remote mountain ecosystems. We did not find any correlation of the number of MPs with local anthropogenic pressure characteristics. In turn, the significant correlation with lake area, coastline length, lake volume, and catchment area indicated airborne sources, including global transport of MPs to the lakes with reduced water outflow.

Impact of dietary exposure to polyester microfibers on hematology, serology and histology in a mouse model

Synthetic fabrics, especially polyester, are a primary source of microplastic fibers (MFs), but there is limited data on their accumulation and dose related health impact in living organisms. This study examined the effects of ingested polyester microfibers (PE-MFs) on hematology, histopathology, and serum biochemistry in albino mice. Mice were given varying doses of PE-MFs (100, 200, 400 and 800 μg/d/mice) for a duration of thirty-five days and a notable decreases in certain hematological parameters such as RBCs, Hb, and platelets, and increases in MCV and MCH was noted at (p < 0.05) thereby indicating possible inflammatory response within the body resulting from ingestion of these MFs. Liver enzymes (ALT, AST, and alkaline phosphatase) and histopathological changes in the liver and gastrointestinal tract also exhibited significant variations, with higher levels seen in the group receiving the highest dose of PE-MFs (800 μg/d/mice). In summary, increased exposure to PE-MFs led to a dose-related impact and notable alterations in histopathological, hematological, and serum biomarkers in albino mice. This study highlights the potential hazards associated with dietary exposure to PE-MFs in mammals and emphasizes the need for further research in this field.

Integrative models for environmental forecasting of phthalate migration from microplastics in aquaculture environments

The pervasive utilization of plastic tools in aquaculture introduces significant volumes of microplastic fibers, presenting a consequential risk through the leaching of additives such as phthalates. This study scrutinizes the leaching dynamics of six prevalent phthalate esters (PAEs) from thirteen plastic aquaculture tools comprising polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (PE), with ΣPAEs ranging from 0.24 to 4.26 mg g−1. Di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) emerged as predominant, marking significant environmental concern. Over a 30-day period, leaching quantities of Σ6PAEs from PET, PP, and PE fibers reached 36.65 μg g−1, 21.87 μg g−1 and 19.11 μg g−1, respectively, influenced by factors such as time, temperature, turbulence, and salinity. Notably, turbulence exerted the most pronounced effect, followed by temperature, with negligible influence from salinity. The kinetic models aligning with interface diffusion control was developed, predicting PAEs' leaching behavior with activation energies (Ea) indicative of the process's thermodynamic nature. The application of this model to real-world aquaculture waters forecasted significant risks, corroborating with empirical data and underscoring the pressing need for regulatory and mitigation strategies against PAEs contamination from aquaculture practices.

The toxic effects of exposure to fibrous and fragmented microplastic in juvenile rockfish based on two omics approach

Although the hazards of environmental microplastics (MPs) are well known, it is unclear which of their characteristics have the greatest effects on organism. We investigated the toxic effects of oral administration according to physical properties, including the shape of fragmented polyethylene terephthalate (PET) (FrPET) and fibrous PET (FiPET) MPs. After 72 h of exposure, apoptosis and phagocytic activity varied significantly among juvenile rockfish (Sebastes schlegeli) exposed to both FrPET and FiPET. The levels of immune-related genes and hepatic metabolic activity also increased after exposure to both shapes of MPs, but the variation in responses was greater in fish exposed to FiPET compared with those exposed to FrPET. The transcriptomic and metabolomics analysis results indicated that the maintenance and homeostasis of immune system was affected by oral exposure to FrPET and FiPET. The amino acid metabolic processes were identified in rockfish exposed to FrPET, but the notch signaling pathway were evident in the FiPET exposure group. Metabolomics analysis revealed that oral ingestion of MP fibers led to a stronger inflammatory response and greater oxidative stress in juvenile rockfish. These results can be used to understand environmentally dominant MP toxic effects such as type, size, shapes, as well as to prioritize ecotoxicological management.

Microplastic contamination in commercially available table salts of Pakistan

ABSTRACT Microplastics (MPs) are widespread across the globe, in every part of the environment. Their presence is expected to triple by 2060, posing risks to both human and environmental health. The present study investigated microplastic contamination using a stereomicroscope and GC-MS in table salts of Pakistan from different origins – sea, rock, and lake. Seventeen branded and 2 unbranded salts showed about 30 to 35 microplastics were present per kilogram of salts on average with the highest 125 MPs/Kg and lowest 30 MPs/Kg. Morphologically, black-coloured microplastic fibres were found to be predominant, and polyethylene was the most abundant chemical component. This study showed that assuming 30–35 MPs per kilogram of salts are found on average, people in Bangladesh are ingesting more microplastics through table salts compared to other regions, and Pakistan ranks lowest because of its lower salt consumption.

Microplastic and Associated Black Particles From Road‐Tire Wear: Implications for Radiative Effects Across the Cryosphere and in the Atmosphere

AbstractThe environmental effects of airborne micro‐ and nano‐size plastic particles are poorly understood. Microscopy and chemical analyses of atmospherically deposited particles on snow surfaces at high elevation (2,865–3,690 m) in the Upper Colorado River basin (UCRB; Colorado Rocky Mountains) revealed the presence of black substances intimately associated with microplastic fibers, particles interpreted to have originated as tire matter. Identical and similar particles occur in shredded tires and road‐surface samples. The substance responsible for the black color of all tires is carbon black, a graphitic light‐absorbing tire additive produced by hydrocarbon combustion that homogeneously permeates the mixture of tire polymers and other additives. Such black tire matter may thus exert radiative effects closely similar to those of black carbon. The presence in snow of many organic compound types common to tires, measured by two‐dimensional gas chromatography, suggests that atmospherically deposited black road‐tire‐wear matter is among the light‐absorbing particulates that advance the onset and rate of snow melt in the UCRB. The mass of road‐tire‐wear particles shed from vehicles may be estimated by multiplying measured amounts of eroded tire‐per‐distance traveled by vehicular distances. Under a combination of measurements and assumptions about the amounts and radiative properties of atmospheric tire‐wear particles, the radiative effects of these particles might add about 10%–30% to those effects from black carbon, an estimate ripe for revision. On regional and global scales, the amounts and effects of emitted and deposited tire‐wear matter likely vary by factors of geographic source, transport pathway, and depositional setting.

An innovative strategy for polyester microplastic fiber elimination from laundry wastewater via coupled separation and degradation using TiO2-based photocatalytic membrane reactor

Microplastics (MPs) pollution, particularly from polyester microplastic fibers (PMPF) released during laundry processes, has become a significant environmental issue. This study explores an effective solution for rejecting and degrading both simulated and real PMPF in laundry wastewater using a TiO2-based photocatalytic membrane reactor (PMR). The immobilized-PMR integrates an Ag-decorated TiO2 (Ag-TiO2) catalyst onto an Al2O3 ceramic membrane, combining the photocatalytic capabilities of TiO2 with the enhanced efficiency provided by silver nanoparticles’ plasmonic effect. This setup aims to optimize PMPF degradation under ultraviolet-C (UVC) light irradiation. The performance of the immobilized-PMR was assessed with simulated and real laundry wastewater containing PMPF. Results showed that the Ag-TiO2 catalytic membrane achieved up to 99.9 % rejection of both simulated and real PMPF, and a 23.2 % degradation rate of simulated PMPF after 48 h of UVC irradiation. Detailed morphological analyses via FESEM and chemical characterization through FTIR and GC/MS confirmed substantial degradation of polyester fibers. This study demonstrates the potential of the TiO2-based immobilized-PMR as a scalable, efficient solution for mitigating fibrous MP pollution in wastewater. The approach combines photocatalytic degradation with membrane filtration, effectively rejecting and degrading fibrous MPs, thereby reducing their environmental impact.

Links between fecal microplastics and parameters related to metabolic dysfunction-associated steatotic liver disease (MASLD) in humans: An exploratory study

Microplastics (MPs) can persist in the environment and human body. Murine studies showed that exposure to MPs could cause metabolic dysregulation, contributing metabolic dysfunction-associated steatotic liver disease (MASLD) or steatohepatitis (MASH). However, research on the role of MPs in humans is limited. Thus, we aimed to assess links between human fecal MPs and liver histology, gene expression, immune cells and intestinal microbiota (IM). We included 6 lean healthy liver donors and 6 normal liver (obese) and 11 MASH patients. Overall, pre-BSx, we observed no significant differences in fecal MPs between groups. However, fecal MP fibers and total MPs positively correlated with portal and total macrophages and total killer T cells while total fecal MPs were positively correlated with natural killer cells. Additionally, 19 genes related to immune system and apoptosis correlated with fecal MPs at baseline. Fecal MP fibers correlated positively with fecal Bifidobacterium and negatively with Lachnospiraceae. Patients with MASH (n = 11) were re-assessed 12-months post-bariatric surgery (BSx) and we found that those with persistent disease (n = 4) had higher fecal MP fragments than those with normalized liver histology (n = 7). At 12-month post-BSx, MP fragments positively correlated with helper T cells and total MPs positively correlated with natural killer T cells and B cells. Our study is the first to look at 1) the role of MPs in MASH and its association with IM, immune cells and hepatic gene expression and 2) look at the role of MPs longitudinally in MASH persistence following BSx. Future research should further explore this relationship.

The fate of airborne microfibers in the human respiratory tract in different microenvironments

Αirborne microplastics (MPs) are considered an important exposure hazard to humans, especially in the indoor environment. Deposition and clearance of MPs in the human respiratory tract (HRT) was investigated using the ExDoM2 dosimetry model, modified to incorporate the deposition and clearance of MPs fibers. Fiber deposition was calculated via the fiber equivalent aerodynamic diameter determined using their properties such as size, density and dynamic shape factor. Scenario simulations were performed for elongated particles of cylindrical (base) diameters 1 μm and 10 μm and aspect ratios (ratio of fiber length to base diameter) 3, 10 and 100. Modelling results showed that the highest fiber deposition occurred in the extra-thoracic region due to large particles (fiber cylindrical diameter dp > 0.1 μm), whereas particle length (via the aspect ratio) had an influence mainly on smaller base-diameter fibers (dp < 0.1 μm) that deposited predominantly in the alveolar region. The ExDoM2 dosimetry model was also used to calculate fiber deposition in the HRT using experimental data for microplastic fiber and fragment concentrations in different microenvironments. The highest deposited number dose (220 fibers) after a 24-hour exposure was calculated in the microenvironment (bus) that had the highest fiber concentration (17.3 ± 2.4 fibers/m3). After clearance, the majority (66.4 %) of the average deposited fiber mass was transferred from the respiratory tract to the esophagus via mucociliary clearance, 32.6 % was retained in the respiratory tract, 1 % passed into the blood, and a very small amount (0.0004 %) was transferred to the lymph nodes.

Visible Combined Near-Infrared in Situ Imaging Revealed Dynamic Effects of Microplastic Fibers and Beads in Zebrafish.

Microplastics (MPs) as emerging contaminants are widely present in the environment and are ubiquitously ingested and accumulated by aquatic organisms. MPs may be quickly eliminated after a brief retention in aquatic animals (such as the digestive tract); thus, understanding the damage caused by MPs during this process and whether the damage can be recovered is important. Here, we proposed the use of visible light imaging to track MPs combined with near-infrared (NIR) imaging to reveal the in situ impacts of MPs. The combination of these two techniques allows for the simultaneous investigation of the localization and functionality of MPs in vivo. We investigated the effects of two types of MPs on zebrafish, microplastic fibers (MFs) and microplastic beads (MBs). The results showed that MPs larger than 10 μm primarily accumulated in the intestines of zebrafish. Both MFs and MBs disrupted the redox balance of the intestine, and the location of the damage was consistent with the heterogeneous accumulation of MPs. MFs caused greater and more difficult-to-recover damage compared to MBs, which was closely related to the slower elimination rate of MFs. Our study highlights the importance of capturing the dynamic toxicological effects of MPs on organisms. Fibrous MPs and spherical MPs clearly had distinct effects on their toxicokinetics and toxicodynamics in fish.

Optimising microplastics analysis for quantifying and identifying microplastic fibres in laundry wastewater

Current methods for measuring microplastic fibres (MPF) are cumbersome, time consuming and unscalable for routine high throughput analysis. This study reports a method for rapidly extracting, quantifying and analysing MPFs in laundry wastewater with several key improvements which vastly enhance overall efficiency and scalability of analysis. FT-IR surveying is employed as a preliminary step in analysis to quickly determine what polymers are present in a sample prior to fluorescence treatment. Using random quadrating, whole 25 mm filter membranes were surveyed in <30 min with high recovery rates. In industrial laundry wastewater samples, polyester was the most common MPF, however acrylic, nylon, cotton and rayon were all ubiquitous. The study also demonstrates that an excitation wavelength of 365 nm was optimal for fluorescing PET fibres like polyester which were stained with Nile Red, but not 495 nm, which is commonly used in microplastic analysis. Finally, a custom ImageJ macro was written to automatically enumerate and describe MPFs on filter membranes using just a single stitched fluorescence image. In just a few seconds, concentrations of up to 40,000 fibres/L were analysed in industrial laundry wastewater samples with a lower particle size limit of 20 μm. This study highlights the need for more optimised and scalable analysis workflows which maintain high levels of reliability and accuracy.