Microplastics

The settling and rising of spherical microplastic particles with different Reynolds numbers, $Re$, were studied using a fully coupled large eddy simulation–discrete element method (LES-DEM) model, where the particles were treated using the immersed boundary method. Twelve different simulations were performed to find the drag coefficient $C_D$, particle trajectories, and wake patterns of both settling and rising microplastic particles. Results were compared to experimental findings from the literature and the comparisons show that the present LES-DEM model produces accurate values for $C_D$ when $Re\lesssim 310$ and qualitatively captures both wake patterns and particle trajectories for $1\lesssim Re\lesssim 5235$. Full article

The toxicity of micro- and nanoplastics in aquatic life is well documented, yet limited information is available on their effects in humans; moreover, most in vitro nanotoxicology studies rely on cancer cells. This study examined the effects of pristine and aged polystyrene micro- and nanoparticles on human dental pulp stem cells. While both particle sizes were internalized by the cells, primarily through endocytosis, they did not affect cell viability. In contrast, leachates from particles, aged for one month in culture medium, significantly reduced viability, indicating that toxicity arises from degradation byproducts rather than the particles themselves. Atomic force microscopy confirmed surface changes in aged plastics. Both particle sizes disorganized the cytoskeleton, leading to reduced actomyosin cortex integrity. Gene expression analysis revealed that leachates and aged particles activated inflammatory pathways, markedly increasing IL-8 and TGF-β1 expression, while also decreasing SOD levels associated with oxidative stress. No notable effects were observed on genes related to stemness or senescence. These results suggest that, while pristine micro- and nanoplastics may be relatively inert, their degradation products pose greater toxicological risks to human health. The findings highlight the importance of considering leachate toxicity in plastic pollution studies and demonstrate the value of stem cell-based models for evaluating the cellular and molecular impacts of environmental contaminants on human health. Full article

Data on microplastic contamination in pristine caves are rare, thus limiting our understanding of its pervasiveness in intact underground ecosystems. Here, we quantified microplastics in sediments from two newly discovered, extremely remote caves (Maucci and Luftloch) and compared them with a frequently visited cave (Trebiciano), all three of which are hydraulically connected to the Reka/Timavo River in the Classic Karst (NE Italy). Sediment samples were collected along river-to-slope transects and analyzed for microplastics using density separation and μFT-IR spectroscopy. Average contamination levels were comparable across caves, ranging from 84.7 to 105.9 items kg⁻¹ (dry weight). Fibers and fragments dominated, with similar polymer spectra across sites—polypropylene (PP, 29–42%), polyethylene (PE, 19–27%), and polyethylene terephthalate (PET, 33–46%). Microplastic abundance systematically increased with elevation, up to ~4–12× from river-proximal to high-bench sediments. Polymer-resolved trends reflected density-coupled, flood-driven sorting with low-density PP and PE accumulated on higher benches and denser PET depleted aloft, indicating slackwater retention at flood crests and re-entrainment of lower benches during recession. These findings suggest that indirect riverine inputs of microplastics outweigh direct human contamination and provide the first baseline for pristine Timavo caves—serving as reference sites for background microplastic levels in the Classic Karst and similar karst systems worldwide. Full article

Microplastics spread through the environment in various ways. Inland waters are an ideal medium for their dispersal, as they collect pollutants from various sources and transport them over long distances. From there, microplastics can enter the marine environment, break down into smaller particles or end up in drinking water treatment plants. However, the fate, transport and potential health effects of microplastics after ingestion of drinking water and water in food are not yet fully understood. It is therefore necessary to evaluate the quantification and identification of microplastics in drinking water by analysing real samples in order to assess the potential impact on human health. To this end, microplastic contamination in 32 treated drinking water samples from a surface water treatment plant in north-eastern Italy were analysed using micro-Fourier transform infrared spectroscopy (µ-FT-IR). The results indicated low levels of contamination, with all the samples containing less than 170 microplastics per litre, which is in line with European drinking water levels. Polyolefins with size 50–500 µm, such as polypropylene and polyethylene, were the predominant polymers detected (50.2%), while surprisingly polyethylene terephthalate was scarcely present (0.1%, size range 10–50 µm). Statistical analysis revealed a significant negative correlation between microplastic concentration and sampling volume, with larger volumes yielding fewer particles. This inconsistency likely results from the lack of bottle rinsing when only a fraction of the sampling volume is filtered. It was also found that rinsing the sampling bottles with ethanol alone prior to analysis was sufficient to ensure accurate quantification. These results highlight the challenges in standardising the detection of microplastics in drinking water and underline the need for optimised sampling protocols. Full article

Micro- and nanoplastics (MNPs) are a new type of pollutant that are widely present in terrestrial ecosystems due to agricultural plastics, sludge use, deposition, and litter degradation. Plants can absorb them through the soil and atmosphere, with adverse effects on plant growth and development. Several studies have reported the effects of MNPs on plant physiology, biochemistry, and toxicity. However, the food chain risk of plant uptake of MNPs has not been systematically studied. This review synthesizes current research on plant MNP pollution, focusing on the uptake and transport mechanisms of MNPs by plants, influencing factors, and health hazards. The size, type, and surface charge characteristics of MNPs, as well as environmental conditions, are key factors affecting MNP absorption and accumulation in plants. Furthermore, when MNP-enriched plants are consumed by humans and animals, the accumulated MNPs can diffuse through the bloodstream to various organs, impairing physiological functions and causing a range of health problems. While a comprehensive, traceable investigation of the transmission of MNPs through the terrestrial food chain remains unconfirmed, health risk signals are unequivocal—dietary intake is the primary route of human exposure to MNPs, with direct evidence of their bioaccumulation in human tissues. Addressing this critical research gap, i.e., systematically verifying the full terrestrial food chain translocation of MNPs, is therefore pivotal for conducting robust and comprehensive assessments of the food safety and health risks posed by MNPs. This study analyzed a total of 154 literature sources, providing important theoretical insights into the absorption, transport, and accumulation of MNPs in plants, as well as the health risks associated with their transfer to humans through the food chain. It is expected to provide valuable reference for the research on the transfer of MNPs in the “soil-plant-human” chain. Full article

Development of novel methods for the separation, characterization, and analysis of microplastics is an urgent task. Countercurrent chromatography (CCC) has been proven to be an efficient method for the separation and preconcentration of microplastics from aqueous samples using two-phase water–oil systems. However, the efficiency of separation of microplastics from natural seawater by CCC has not been studied so far. Here we demonstrate the high efficiency of separation of microplastics from Black Sea water samples by CCC. The separation efficiency of PE, PP, PS, PVC, PET microparticles of different size (<63, 63–100, 100–250 μm) from spiked seawater samples is about 100%. The method enables the separation of microplastics with size at least down to 1 μm to be performed. The combination of CCC and pyro-GC-MS was applied to the quantification of microplastics in Black Sea water samples. Seven microplastics (μPE, μPP, μSBR, μPVC, μPET) were determined in the seawater samples under study. The total concentration of determined microplastics was about 6.5 μg/L. It was shown that the combination of CCC and pyro-GC-MS enabled robust analytical data to be obtained and hence can be applied to an accurate quantification of microplastics in seawater. Full article

Plastic has transitioned rapidly from a revolutionary material to a global environmental concern, primarily due to mismanagement. Synthetic polymers have quickly gained widespread use due to their versatility, durability, and affordability. However, the properties making plastic indispensable contribute to its permanence in the environment, where it breaks down into microplastics—tiny particles that are typically classified in the size range from 0.1 μm to 5 mm. These particles can now be found in all ecosystems, including the oceans, soil, atmosphere, and within living organisms, raising global concerns about their long-term environmental and health impacts. This review critically examines the current status and potential for identifying, analyzing, and mitigating microplastic pollution. In this paper, we particularly focus on the destructive and non-destructive analytical methods used for microplastic identification and characterization, examining their technical capabilities and limitations, the challenges in maintaining sample integrity, and the reliability of their quantification methods. In addition, the review addresses microplastic removal strategies, from laboratory procedures to real-world applications, examining barriers to implementation and the limited availability of existing solutions. Finally, the review highlights the urgent need for standardized protocols, regulatory frameworks, and interdisciplinary collaboration to address the multifaceted nature of microplastic pollution. Full article

Microplastic (MP) pollution poses an emerging environmental concern, yet current methods for isolation and quantification are often time-consuming, costly, and poorly adapted to real-world variability. In this study, a workflow for the preparation, filtration, and quantification of MP standards, emphasizing environmental relevance and methodological efficiency, was developed and evaluated. To address the scarcity of irregularly shaped MP standards, low-cost, environmentally representative standards were lab-prepared by grinding and sieving plastic sheets. These MPs were successfully categorized according to sizes up to ~250 μm and dyed for enhanced visibility. The filtration efficiency for two systems, a long-circuit pump (LC-pump) and a short-circuit vacuum (SC-vacuum), was compared. The SC-vacuum method demonstrated a more than 11-fold increase in filtration speed and higher MP recovery rates for both polystyrene and polypropylene standards. Ethanol-based solvents significantly improved MP dispersion and recovery for irregular shapes of the MPs, including polystyrene and polypropylene. Finally, a user-guided machine learning tool (Ilastik) was implemented for automated MP quantification. Ilastik showed a strong correlation with manual counting (r = 0.824) and reduced variability, offering a reproducible and time-efficient alternative. By cutting down cost, time, and technical complexity relative to existing MP analysis techniques, this workflow provides a more accessible path toward consistent and scalable environmental MP assessments. Full article

Plastic microbeads, widely incorporated into personal care and cleansing products, have emerged as a pervasive contaminant in freshwater systems, including in North America. Historical estimates indicate that North American consumers alone contributed trillions of microbeads daily to municipal wastewater, with global usage reaching quadrillions per day. Regulatory actions in 2017 in Canada and the USA to ban microbeads in personal care products appear to have greatly reduced microbead contamination levels, including a decrease in microbead proportion from 2 to 5% to 0.003%, and an 86% reduction in PE microbead discharge from wastewater treatment plants. Yet these particles still persist in the environment due to their resistance to degradation and continued release from unregulated sources, including industrial abrasives and certain cleaning agents. Studies across the Great Lakes, one of the world’s largest freshwater systems, have documented widespread microbead contamination in surface waters, sediments, and shorelines, highlighting their persistence and accumulation. This review synthesizes findings from key studies conducted between 2013 and 2017 to establish a pre-ban baseline of microbead distribution in the Great Lakes, and presents new data collected from 2018 to 2021 as a post-ban contamination assessment. The review emphasizes the unique challenges posed by microbeads within the broader context of microplastic pollution. We also hope that this paper underscores the critical role of polymer chemists and engineers in developing innovative materials and removal strategies to mitigate future contamination. Full article

Atmospheric deposition of microplastics (MPs) contributes to the contamination of both terrestrial and aquatic environments. Roads show high MP deposition, yet the factors influencing the deposition rate and characteristics (polymer types and sizes) remain insufficiently understood. In this study, we investigated atmospheric MPs in two size fractions: 45–300 μm (small) and ≥300 μm (large), collected monthly for one year using a bulk deposition method. Large MPs were visually sorted and characterized via ATR-FTIR spectroscopy for polymer identification, while smaller MPs were quantified by measuring non-purgeable organic carbon (NPOC) using a total organic carbon (TOC analyzer), without polymer characterization. Deposition rates of large MPs ranged from 3 to 9 million pcs/ha/month, while small MPs averaged 72.2 gC/ha/month. Identified polymers included PP, PE, PS, PVC, PET, PVAC, PA, and PU. Traffic mainly influenced large MPs, especially PET and PA, near roads, whereas wind direction and intensity enhanced dispersal of small MPs and the transport of PVC, PS, and PU. Predominant easterly winds also indicated possible contributions from industrial and other anthropogenic sources. By focusing on the road area, integrating influence of traffic and meteorological factors, and adapting TOC-based carbon quantification, this study provides new insights and extends existing knowledge in the field. Full article

The toxic effects of soil heavy metals and microplastics on plants have been extensively documented, with some researchers having conducted studies exploring the combination of these two factors. Preliminary findings indicate that their combined action can “reduce biomass, exacerbate oxidative stress, and inhibit photosynthesis,” and the potential mechanisms of this combined toxicity are currently being explored. However, these combined effects remain unclear, with conflicting conclusions across studies. Research subjects are relatively fragmented, and systematic summaries are lacking. This paper systematically reviews current research findings on the combined toxic effects of microplastics and Cd on plants, specifically focusing on the following factors: (1) the mechanisms and influencing factors of Cd adsorption by microplastics: electrostatic adsorption is the primary mechanism, and soil environmental factors are significant influencers; (2) microplastics’ altering of the available Cd content in soil: soil environmental conditions can be modified to increase or decrease available Cd concentrations; (3) The “synergistic or antagonistic” toxic effects of microplastics and Cd on plants. Future research directions warranting in-depth investigation are also identified in this study. Full article

Microplastic (MP) contamination along coastlines is a globally recognized environmental concern. This paper investigates the seasonal and cross-shore distribution of large and small microplastics (LMPs and SMPs) at four sites along the Ferrara coast in the northern Adriatic Sea (Italy). A combination of sampling and analytical approaches was employed to characterize the typology, morphology, and size of MPs. A subsample of LMPs was analyzed by Raman spectroscopy to determine polymers’ composition. The mean abundances recorded were 5.66 ± 13.15 LMPs/m² and 2402.19 ± 1169.85 SMPs/m². Among the LMPs, pellets and fragments, essentially cream and white in color, were dominant. The samples were predominantly composed of polyethylene, polypropylene, and polyethylene terephthalate. SMPs primarily consisted of black fibers. LMPs and SMPs displayed their lowest abundances in winter and cross-shore patterns indicated preferential accumulation at dune foot and crest. Since the study sites are located downstream of the Po and Reno river mouths, urban and riverine discharges, as well as emissions from plastic-processing industries, are likely major contributors to the observed MPs. Full article

Nanoplastics (NPs) pose significant risks due to their small size and ability to penetrate biological tissues. However, the molecular pathways and cellular mechanisms affected by NP exposure in marine teleosts remain poorly understood, especially in tropical reef fishes. This study examined the impact of short-term (7 days) waterborne exposure of 100 nm-carboxyl-modified polystyrene NPs on the false clownfish (Amphiprion ocellaris) exposed at two daily concentrations: low (20 µg/L, environmentally relevant) and high (2000 µg/L). A multidisciplinary approach, including biochemical and transcriptomic analyses, was conducted to assess toxic effects. Biochemical assays revealed limited changes in antioxidant defenses (CAT, GR, GST, TOSC). However, the Integrated Biomarker Response index (IBRv2i) suggested a compromised physiological condition, supported by transcriptomic data. Transcriptomic profiling revealed 409 significantly differentially expressed genes (DEGs) in the high-concentration and 354 DEGs in the low-concentration groups, with 120 shared DEGs mostly upregulated and indicative of a core molecular response. Collectively, the transcriptional profile of the low-concentration group resembled an early-warning, energy-reallocation strategy aimed at preserving essential sensory functions while minimizing expendable functions. The high-concentration group amplified the shared stress signature and recruited an additional 289 unique genes, resulting in pronounced enrichment of Gene Ontology terms related to “muscle contraction”, “oxygen transport”, “hydrogen-peroxide catabolism”, and “extracellular-matrix”. This study demonstrates that PS-NP exposure can alter gene expression and physiology in juvenile reef fish, even at environmentally relevant concentrations. Molecular responses varied with concentrations highlighting the role of exposure level in influencing biological systems and potential long-term impacts of NP pollution in marine environments. Full article

The study investigates the presence of emerging contaminants in a river within a watershed located in the Brazilian semiarid region, specifically within the Caatinga biome, emphasizing the importance of environmental monitoring in areas that have historically been underrepresented in scientific research. The analysis focused on the associations between microplastics and pharmaceutical compounds, demonstrating that the discharge of untreated domestic effluents and the low efficiency of sanitation systems increase water resource contamination and threaten water security. The interdependence between these variables underscores the need for integrated public policies for waste management, complemented by environmental education strategies and technological innovations. The work makes an unprecedented contribution to expanding knowledge about emerging pollutants in semiarid environments, highlighting the urgency of holistic approaches, continuous monitoring, and strengthening environmental governance to ensure the sustainability and resilience of ecosystems like the Caatinga in the face of the challenges posed by global environmental change, urban growth, and those outlined in the Sustainable Development Goals. Full article

Plastic pollution is a major global challenge, especially nanoplastics (NPs) emerging as harmful pollutants due to their small size, reactivity, and persistence in ecosystems. Among them, cigarette butts composed of cellulose acetate (CA) are one of the most widespread and hazardous sources of terrestrial NPs. In this study, the immunotoxic, biochemical, and histopathological effects of cellulose acetate nanoplastics (CA-NPs) derived from smoked cigarette butts (SCB-NPs), unsmoked cigarette butts (USCB-NPs), and commercial cellulose acetate (CCA-NPs) were evaluated on the earthworm Allolobophora caliginosa. Adult worms were exposed for 30 days to 100 mg/kg CA-NPs in artificial soil under controlled laboratory conditions. Results revealed that SCB-NPs induced the most pronounced alterations, including increased lysozyme and metallothionein levels, reduced phagocytic and peroxidase activities, and depletion of protein and carbohydrate reserves. Histological examination showed vacuoles in epithelial layer vacuolization, space between muscle fiber disruption, and degeneration in gut and body wall, especially under SCB-NP exposure. USCB-NPs and CCA-NPs caused milder but still significant effects. Taken together, these findings highlight that the high toxicity of SCB-NPs is due to the presence of combustion-derived toxicants (nicotine, polycyclic aromatic hydrocarbons, and heavy metals), which exacerbate oxidative stress, immune suppression, and tissue damage in soil invertebrates. This study underscores the ecological risk of cigarette butt-derived NPs and calls for urgent policy measures to mitigate their terrestrial impacts. Full article

The global proliferation of plastics and their degradation into microplastics (<5 mm) have created a pervasive environmental crisis with severe ecological and human health consequences. Despite the exponential growth in microplastic research over the past decade, standardized protocols are still lacking. The absence of consistent sampling, analysis, and reporting methods limits data comparability, interoperability, and harmonization across studies. This study conducted a systematic bibliographic review of 355 peer-reviewed articles published between 2010 and 2022 that investigated microplastics in freshwater as well as marine water and sediment environments. The goal was to evaluate methodological consistency, sampling instruments, measurement units, reported characteristics, and data-sharing practices to identify pathways toward harmonized and FAIR (Findable, Accessible, Interoperable, and Reusable) microplastic data. Results show that 80.6% of studies focused on marine environments, 18% on freshwater, and 1.4% on both. This highlights persistent data gaps in freshwater systems, which function as key transport pathways for plastics to the ocean. Most studies targeted water (59%) rather than sediment (41%) and were mostly based on single-time sampling, limiting long-term analyses. Surface layers (<1 m) were predominantly sampled, while deeper layers remain understudied. Nets, particularly Manta, neuston, and plankton nets were the dominant tools for water sampling, whereas grabs, corers, and metallic receptacles were used for sediments. However, variations in mesh size and sampling depth introduce substantial biases in particle size recovery and reduce comparability across studies. The most common units were counts/volume for water and counts/g dry weight for sediments, but more than ten unit expressions were identified, complicating conversions. Only 35% of studies reported all four key microplastic characteristics (color, polymer type, shape, and size), and less than 20% made datasets publicly available. To advance harmonization, we recommend the adoption of consistent measurement units, mandatory reporting of key metadata, and wider implementation of open data practices aligned with the FAIR principles. These insights provide a foundation for developing robust monitoring strategies and evidence-based management frameworks. This is especially important for freshwater systems, where data remain scarce, and policy intervention is urgently needed. Full article

Microplastics (MPs) are recognised as emerging vectors for hydrophobic organic contaminants in aquatic environments due to their relatively large surface area and the diversity of their polymer chemistries compositions. This study investigates the sorption behaviour of two priority polycyclic aromatic hydrocarbons (PAHs), pyrene (PYR) and fluoranthene (FLU), onto six common MPs: poly(m-xylene adipamide) (PA-MXD6), high- and low-density polyethylene (HDPE, LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polylactic acid (PLA). Sorption isotherms and kinetics were evaluated under simulated freshwater conditions at environmentally relevant concentrations (1–50 µg·L⁻¹). Despite the low MP concentration used (0.2 g·L⁻¹), over 80% of the initial PAH content was removed by polyolefins, and more than 50% by all other MPs. Sorption capacity was strongly dependent on particle surface area. Langmuir, Henry, and Freundlich isotherms models were fitted, with linear behaviour prevailing at low concentrations. Analysis using the Dubini–-Radushkevich model confirmed that sorption involves chemisorption contributions, mainly through π–π interactions and hydrophobic interactions (polyolefins). Mechanistically, molecular diffusion within the MP matrix was not governing the sorption process, as diffusion coefficients varied with particle size instead of polymer chemistry. Instead, sorption appears to be governed by PAH diffusion through the hydrodynamic boundary layer and subsequent retention on the MP surface. Empirically, kinetic data fitted the pseudo-second-order model, further supporting that the sorption process involves chemisorption. These findings highlight the role of MPs as vectors for PAHs in freshwater systems and their potential application in contaminant removal. Expressing sorption per unit surface area is recommended for accurate assessment. This work contributes to understanding the environmental behaviour of MPs and their implications for pollutant transport and toxicity. Full article

Microplastics (MPs) are considered to be dominant agents responsible for serious contamination in environmental and biological systems. Despite a huge increase in research on these contaminants, there are still considerable uncertainties and progress to be made on the exposure pathways of biological systems, modes of detection, and toxicity assessments. Therefore, developing a critical review of MPs is crucial due to growing evidence of their harmful effects on human health. In the current review, we aim to emphasize the potential toxic effects of MPs on different biological systems in humans, the mechanisms of their toxic effects, and gaps in our knowledge on risk assessment. Importantly, we focus on the risks posed by MPs for fetuses and child health. To ensure methodological rigor, the current review follows the PRISMA guidelines, explicitly detailing the literature search strategy and inclusion/exclusion criteria. The present review summarizes potential sources of MP generation, exposure pathways, quantitative analyses of dietary exposure, estimated daily intake, particle/leachate toxicity evidence, detection in different human organs, and potential toxic effects. MPs cause toxicity in several biological systems in humans, such as the gastrointestinal, nervous, hepatic, endocrine, respiratory, and reproductive systems. In addition, these particles are known to cause oxidative stress, alter metabolism, and affect gut microflora and gastrointestinal functions. Importantly, the current review also discusses the challenges encountered in conducting risk assessments for MPs and the approaches for counteracting these challenges. Finally, the review concludes by recommending future research directions in terms of counteracting the toxic effects of MPs on human health. Full article