White and wonderful? Microplastics prevail in snow from the Alps to the Arctic

Microplastics in bulk atmospheric deposition along the coastal region of Victoria Land, Antarctica

The increasing global concern over microplastic pollution has driven a surge in research efforts aimed at detecting microplastics across various ecosystems. Airborne microplastics (MPs) have been identified in remote environments worldwide, including Antarctica. However, data on bulk atmospheric deposition remain scarce. From January to December 2020, atmospheric deposition was directly collected using passive samplers placed in eight sites across Victoria Land. Using Raman Microspectroscopy, MPs were identified in six out of the seven samples collected (one sample was lost due to the extreme weather conditions). The average daily MP deposition for Victoria Land was 1.7 ± 1.1 MPs m-2 d-1, with values ranging from 0.76 to 3.44 MPs m-2 d-1. The majority (53 %) of MPs found in the atmospheric deposition were in the size class of 5-10 μm, and the main shape of MPs was fragments (95 %). The predominant plastic type was polypropylene (31 %), followed by polyethylene (19 %) and polycarbonate (12 %). Polystyrene, polyester, styrene and polyethylene terephthalate each accounted for ~6 %. Microplastics identified in the coastal sites may have local origins, potentially associated with scientific activities at research stations. Conversely, a backward trajectories analysis suggested a potential contribution of atmospheric transport to microplastic deposition at Larsen Glacier and Tourmaline Plateau, the two most remote sites of the study area, where the highest MP concentrations were detected. Our findings present the first evidence of microplastics in the Antarctic atmospheric deposition directly collected via passive samplers, highlighting the need for continued monitoring and research to assess the environmental impact of MPs, particularly in sensitive and remote ecosystems like Antarctica.

Sources, interactions, influencing factors and ecological risks of microplastics and antibiotic resistance genes in soil: A review

Microplastics (MPs) and antibiotic resistance genes (ARGs) are gaining increasing attention as they pose a threat to the ecological environment and human health as emerging contaminants. MPs has been proved to be a hot spot in ARGs, and although it has been extensively studied in water environment, the results of bibliometrics statistical analysis in this paper showed that relevant studies in soil ecological environment are currently in the initial stage. In view of this, the paper provides a systematic review of the sources, interactions, influencing factors, and ecological risks associated with MPs and ARGs in soil environments. Additionally, the mechanism and influencing factors of plastisphere formation and resistance are elaborated in detail. The MPs properties, soil physicochemical properties, soil environmental factors and agricultural activities are the primarily factors affecting the interaction between MPs and ARGs in soil. Challenges and development directions of related research in the future are also prospected. It is hoped that the review could assist in a deeper comprehension and exploration of the interaction mechanism between MPs and ARGs in soil as well as the function of MPs in the transmission process of ARGs among diverse environmental media and organisms, and provide theory basis and reference for the MPs and ARGs pollution control and remediation in soil.

Microplastics and climate change: the global impacts of a tiny driver

Microplastic pollution and climate change, the two seemingly distinct phenomena of global concern, are interconnected through various pathways. The connecting links between the two include the biological carbon pumps in the oceans, the sea ice, the plastisphere involved in biogeochemical cycling and the direct emissions of greenhouse gases from microplastics. On one hand, the presence of microplastics in the water column disrupts the balance of the natural carbon sequestration by affecting the key players in the pumping of carbon, such as the phytoplankton and zooplankton. On the other hand, the effect of microplastics on the sea ice in Polar Regions is two-way, as the ice caps are transformed into sinks and sources of microplastics and at the same time, the microplastics can enhance the melting of ice by reducing the albedo. Microplastics may have more potential than larger plastic fragments to release greenhouse gases (GHGs). Microbe-mediated emission of GHGs from soils is also now altered by the microplastics present in the soil. Plastisphere, the emerging microbiome in aquatic environments, can also contribute to climate change as it hosts complex networks of microbes, many of which are involved in greenhouse gas production. To combat a global stressor like climate change, it needs to be addressed with a holistic approach and this begins with tracing the various stressors like microplastic pollution that can aggravate the impacts of climate change.

Abundant small microplastics hidden in water columns of the Yellow Sea and East China Sea: Distribution, transportation and potential risk

Microplastics (MPs) pose significant concerns for marine ecological security due to their minuteness and ubiquity. However, comprehensive knowledge on their distribution and fate in seawater columns remains limited. This study investigated the abundances and characteristics of MPs across 3-6 water layers in the South Yellow Sea and East China Sea. Results indicate that high-abundance small MPs (< 100 µm) (average 6567 items/m3) were hidden beneath the sea-surface, predominantly fine-grained particles (< 20 µm) and high-density polymers (> 1.03 g/cm3). The total suspended MPs (5.0-834.2 µm) are estimated at 2.9-3.1 × 1017 particles, with most of them occurring in upper layers. In profiles, their distribution varied by physical properties with depth; fragment-shaped and high-density MPs increased in proportion at greater depths, contrasting with fibrous MPs. These MPs originated primarily from the Yangtze River and their winter transport was driven by the Yangtze River Dilution Water, East China Sea Coastal Current, and Yellow Sea Warm Current, resulting in their accumulation in coastal and estuarine regions. Consequently, the Yangtze River Estuary ecosystem faces substantial risks from MP pollution throughout the water column. This work unveils the prevalence of small MPs in coastal water columns and intricate interaction between their fate and hydrodynamic conditions.

Floating microplastics in Svalbard fjords: High spatial variability requires methodological consistency in estuarine systems

Microplastic pollution was studied in surface waters of Isfjorden, Svalbard in July 2021 as a part of an international regional harmonisation exercise. Surface microplastics (0.5-5 mm) were sampled with a neuston net in triplicate per study site in several branches of Isfjorden, covering populated and unpopulated fjords. High spatial variability of microplastic abundance (0-32,700 items/km2) was observed within a single fjord resulting from the hydrodynamic pattern formed through the interaction of surface currents, freshwater runoff, and wind conditions. Maximum microplastic abundance was not correlated with the distance from the local source and was instead defined by local small-scale hydrodynamics. Future recommendations for correct assessment of surface microplastics concentration in estuarine environments are presented.

A review on advancements in atmospheric microplastics research: The pivotal role of machine learning

Microplastics (MPs), recognized as emerging pollutants, pose significant potential impacts on the environment and human health. The investigation into atmospheric MPs is nascent due to the absence of effective characterization methods, leaving their concentration, distribution, sources, and impacts on human health largely undefined with evidence still emerging. This review compiles the latest literature on the sources, distribution, environmental behaviors, and toxicological effects of atmospheric MPs. It delves into the methodologies for source identification, distribution patterns, and the contemporary approaches to assess the toxicological effects of atmospheric MPs. Significantly, this review emphasizes the role of Machine Learning (ML) and Artificial Intelligence (AI) technologies as novel and promising tools in enhancing the precision and depth of research into atmospheric MPs, including but not limited to the spatiotemporal dynamics, source apportionment, and potential health impacts of atmospheric MPs. The integration of these advanced technologies facilitates a more nuanced understanding of MPs' behavior and effects, marking a pivotal advancement in the field. This review aims to deliver an in-depth view of atmospheric MPs, enhancing knowledge and awareness of their environmental and human health impacts. It calls upon scholars to focus on the research of atmospheric MPs based on new technologies of ML and AI, improving the database as well as offering fresh perspectives on this critical issue.

Spatio-temporal trends in microplastic presence in the sediments of the River Thames catchment (UK)

This study investigated the spatio-temporal variability of microplastics (MPs) in the sediments of the River Thames (UK) catchment over 30 months (July 2019 - Dec 2021). The average MP concentration was 61 items kg-1 d.w., with fragments <1 mm being dominant and polyethylene (PE) the most common polymer. Adjacent land use influenced MP concentrations and types, with industrial sites showing particularly high levels and a prevalence of small beads and industrial polymers. MP concentrations generally decreased after higher winter flows, likely due to sediment rearrangement or winnowing. This study describes the seasonal concentrations and characteristics of MPs present in sediment from the River Thames catchment, and attempts to identify their likely origin. Further, the study provides new insights into the mobility and fate of MPs in riverine settings under varying flow conditions, which is vital given the predicted increases in flooding under various global heating scenarios.

The Fate of Microplastics in Rural Headwater Lake Catchments

In this study, the fluxes of microplastics (mp) were quantified during a 12-month period for three rural headwater lake catchments in Muskoka-Haliburton, south-central Ontario, Canada. A novel catchment particle balance approach was used, incorporating inputs from atmospheric deposition and stream inflows against lake outflow and sedimentation. This approach provides the first reported observation-based estimates of microplastic residence time in freshwater lakes. Atmospheric deposition had the highest daily microplastic flux (3.95-8.09 mp/m2/day), compared to the inflow streams (2.21-2.34 mp/m2/day), suggesting that it is the dominant source of microplastics to rural regions. Approximately 44-71% of the deposited microplastics were retained in the terrestrial catchments and 30-49% of the microplastics in the stream inflows were retained in the study lakes. Given that output fluxes ranged from 0.72-3.76 mp/m2/day in the sediment and 1.18-1.66 mp/m2/day in the lake outflows, the microplastic residence time was estimated to be between 3 and 12 years, suggesting that lakes are an important reservoir for microplastics. Fibers were the dominant shape in atmospheric deposition, streamwater, and lake water; however, in lake sediment, there was a higher proportion of fragments. Across all media, poly(ethylene terephthalate) was the dominant polymer identified (23%).

Year-round spatial and temporal distribution of microplastics in water and sediments of an urban freshwater system (Jungnang Stream, Korea)

Streams and tributaries can play a significant role in the transport of inland microplastics to rivers and oceans; however, research on microplastics in these water bodies is limited compared to riverine and marine environments. Analyzing microplastic abundance at higher spatial and temporal resolutions is crucial to comprehend the dynamics of microplastics in these water bodies. Therefore, this study investigated year-round spatiotemporal variations of microplastics monthly in surface waters and sediments along the Jungnang Stream, one of the main tributaries to the Han River in South Korea. The mean concentration of microplastics in the stream was 9.8 ± 7.9 particles L-1 in water and 3640 ± 1620 particles kg-1 in sediment. Microplastic concentrations in surface waters during summer were significantly higher than in other seasons, positively linked to increased precipitation and river discharges. Polymer compositions mainly consisted of polyethylene, polypropylene, and polyethylene terephthalate, with the majority of microplastics detected smaller than 200 μm. Fragment-shaped microplastics were predominant over fibrous ones. The estimated annual input and output of microplastics through surface waters were 1.2-207 kg (2.7-150 billion particles) and 11.3-272 kg (17-769 billion particles), with the summer months contributing more than 70% of the total output. The greater microplastics output in the Jungnang Stream's waters compared to its receiving waters (Han River) indicates microplastics transport from water to other environmental compartments, such as sediments. These findings highlight the importance of investigating microplastic abundances in surface waters and sediments with temporal resolution, at least across different seasons. Such investigations offer valuable insights into the spatiotemporal occurrence and dynamic transport of microplastics, providing essential information for water management and the development of policies in freshwater ecosystems.

Microplastic atmospheric pollution in an urban Southern Brazil region: What can spider webs tell us?

The World Health Organization categorizes air pollution as the presence of one or more contaminants in the atmosphere such as smoke, dust, and particulate matter like microplastics, which are considered a priority pollutant. However, only a few studies have been developed on atmospheric pollution, and knowledge about MPs in the atmosphere is still limited. Spider webs have been tested and used as a passive sampling approach to study anthropogenic pollution. Despite this, studies on microplastic contamination using spiderwebs as samplers are scarce. Thus, this study uses spider webs as passive indicators to investigate air quality regarding microplastic contamination in an urbanized area. Therefore, 30 sampling points were selected, and webs of Nephilingis cruentata were collected. The spider webs were dipped in KOH 10 %. After digestion, the solution was washed and sieved through a 90 µm geological sieve. The remaining material was transferred to a Petri dish with filter paper, quantified, and identified by type and color. The chemical composition of the polymers was determined using Raman spectroscopy. 3138 microplastics were identified (2973 filaments and 165 fragments). The most frequent colors were blue and black. Raman spectroscopy revealed five types of polymers: Isotactic Polypropylene, Polyethylene Terephthalate, Polyurethane, Polyamide, and Direct Polyethylene.

Synergistic Effects of Microplastics and Marine Pollutants on the Destabilization of Lipid Bilayers

Microplastics have been detected in diverse environments, including soil, snowcapped mountains, and even within human organs and blood. These findings have sparked extensive research into the health implications of microplastics for living organisms. Recent studies have shown that microplastics can adsorb onto lipid membranes and induce mechanical stress. In controlled laboratory conditions, the behavior and effects of microplastics can differ markedly from those in natural environments. In this study, we investigate how exposure of microplastics to pollutants affects their interactions with lipid bilayers. Our findings reveal that pollutants, such as chemical solvents, significantly enhance the mechanical stretching effects of microplastics. This suggests that microplastics can act as vectors for harmful pollutants, facilitating their penetration through lipid membranes and thus strongly affect their biophysical properties. This research underscores the complex interplay between microplastics and environmental contaminants.

Diving into the Depths: Uncovering Microplastics in Norwegian Coastal Sediment Cores

High concentrations of microplastics (MPs) have been documented in the deep-sea surface sediments of the Arctic Ocean. However, studies investigating their high-resolution vertical distribution in sediments from the European waters to the Arctic remain limited. This study examines MPs in five sediment cores from the Norwegian Coastal Current (NCC), encompassing the water-sediment interface and sediment layers up to 19 cm depth. Advanced analytical methods for MP identification down to 11 μm in size were combined with radiometric dating and lithology observations. MPs were present across all sediment cores, including layers predating the introduction of plastics, with concentrations exhibiting significant variation (54-12,491 MP kg-1). The smallest size class (11 μm) predominated in most sediment layers (34-100%). A total of 18 different polymer types were identified across all sediment layers, with polymer diversity and depth correlations varying widely between stations. Our findings suggest that differences in seafloor topography and the impact of anthropogenic activities (e.g., fishing) lead to varying environmental conditions at the sampling sites, influencing the vertical distribution of MPs. This challenges the reliability of using environmental parameters to predict MP accumulation zones and questions the use of MPs in sediment cores as indicators of the Anthropocene.

Record of microplastic deposition revealed by ornithogenic soil and sediment profiles from Ross Island, Antarctica

Microplastics (MPs) are a global concern as an emerging pollutant, and the investigation on MPs in Antarctic aids in informing their global pollution assessments. Therefore, there are urgent scientific concerns regarding the environmental behavior, origins, influencing factors, and potential hazards of MPs in Antarctica. This study presents the characteristics of MPs from one ornithogenic sediment profile (coded CC) and two ornithogenic soil profiles (coded MR1 and MR2) from ice-free areas on Ross Island, Antarctica. We explored the potential sources of MPs and the main influencing factors for deposition based on their distribution with depth in the profiles. Through laser-infrared imaging spectroscopy (LDIR), a total of 30 polymer types were identified in all samples, with polyethylene terephthalate (PET) and polyvinyl chloride (PVC) as the dominant types, accounting for more than 70% of the total. The abundance of MPs in the CC sediment profile ranged from 2.83 to 394.18 items/g, while in MR1 and MR2 soil profiles, the abundance ranged from 2.25 to 1690.11 and 8.24 to 168.27 items/g, respectively. The size of MPs was mainly concentrated in the range of 20-50 μm, and possible downward movement of certain polymer types was revealed. From the perspective of temporal variation, we suggest that MPs were heavily influenced by local human activities including scientific research, fishing, and tourism, balanced by protective regulations, while no solid evidence was obtained to support strong influence from biological transport through penguins. This research enhances our understanding on the environmental behavior of MPs in the terrestrial systems of remote polar regions.

Spatial distribution of small microplastics in the Norwegian Coastal Current

High concentrations of microplastic (MP) particles have been reported in the Arctic Ocean. However, studies on the high-resolution lateral and vertical transport of MPs from the European waters to the Arctic are still scarce. Here, we provide information about the concentrations and compositions of MPs in surface, subsurface, and deeper waters (< 1 m, ∼ 4 m, and 17-1679 m) collected at 18 stations on six transects along the Norwegian Coastal Current (NCC) using an improved Neuston Catamaran, the COntinuos MicroPlastic Automatic Sampling System (COMPASS), and in situ pumps, respectively. FTIR microscopy and spectroscopy were applied to measure MP concentration, polymer composition, and size distribution. Results indicate that the concentrations of small microplastics (SMPs, <300 μm) varied considerably (0-1240 MP m-3) within the water column, with significantly higher concentrations in the surface (189 MP m-3) and subsurface (38 MP m-3) waters compared to deeper waters (16 MP m-3). Furthermore, the average concentration of SMPs in surface water samples was four orders of magnitude higher than the abundance of large microplastics (LMPs, >300 μm), and overall, SMPs <50 μm account for >80 % of all detected MPs. However, no statistically significant geographical patterns were observed in SMP concentrations in surface/subsurface seawaters between the six sampling transects, suggesting a relatively homogeneous horizontal distribution of SMPs in the upper ocean within the NCC/Norwegian Atlantic Current (NwAC) interface. The Lagrangian particle dispersal simulation model further enabled us to assess the large-scale transport of MPs from the Northern European waters to the Arctic.

Convenient determination of polystyrene microplastics in soils by gel permeation chromatography-ultraviolet detection analysis

Microplastics (MPs), especially polystyrene microplastics (PS-MPs), have emerged a new worldwide pollutant, prompting significant public concern regarding their detection in environmental media. Analysis of PS-MPs in soil remains as a challenging task for analysts due to the highly intricate matrices. This work presents a practical approach for detecting PS-MPs in soil, which involves dilute HCl-assisted extraction and gel permeation chromatography- ultraviolet detection (GPC-UV) analysis. The presence of MPs in soil was confirmed through the use of a scanning electron microscope in conjunction with energy dispersive spectroscopy investigation. PS-MPs was isolated from soil, by agitating it with a diluted HCl solution, filtering the resulting liquid, and dissolving the residue on the filter with THF. The extractant was subsequently determined by GPC-UV. The introduction of a small amount of HCl into the extraction system was found to greatly expedite the settling of soil in water and enhance the efficacy of extracting PS-MPs in about 30 min. The linear range of PS-MPs was from 1.0 to 100 μg/mL with R2 > 0.999. Good reproducibility was obtained with the intra-day relative standard deviation (RSD, n = 3) of 1.36 % and the inter-day RSD (n = 3) of 4.78 %. The concentration of PS-MPs in soil samples were N.D. - 2.33 μg/g, and the good recoveries were 76.7-100.3 %. The corresponding AFGEEprer score was calculated to be 0.59, indicating the concept of green analytical chemistry for the pretreatment method. These results indicated that this method has a powerful potential for the accurate and rapid determination of PS-MPs in soil.

Microplastic Particles Contain Ice Nucleation Sites That Can Be Inhibited by Atmospheric Aging

Recent research has shown that microplastics are widespread in the atmosphere. However, we know little about their ability to nucleate ice and their impact on ice formation in clouds. Ice nucleation by microplastics could also limit their long-range transport and global distribution. The present study explores the heterogeneous ice-nucleating ability of seven microplastic samples in immersion freezing mode. Two polypropylene samples and one polyethylene terephthalate sample froze heterogeneously with median freezing temperatures of -20.9, -23.2, and -21.9 °C, respectively. The number of ice nucleation sites per surface area, ns(T), ranged from 10-1 to 104 cm-2 in a temperature interval of -15 to -25 °C, which is comparable to that of volcanic ash and fungal spores. After exposure to ozone or a combination of UV light and ozone, simulating atmospheric aging, the ice nucleation activity decreased in some cases and remained unchanged in others. Our freezing data suggest that microplastics may promote ice formation in cloud droplets. In addition, based on a comparison of our freezing results and previous simulations using a global transport model, ice nucleation by microplastics will impact their long-range transport to faraway locations and global distribution.

Quantitative analysis of microplastics in beach sand via low-temperature solvent extraction and thermal degradation: Effects of particle size and sample depth

Quantifying trace levels of microplastics in complex environmental media remains a challenge. In this study, an approach combining field collection of samples from different depths, sample size fractionation, and plastic quantification via pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was employed to identify and quantify microplastics at two public beaches along the northeast coast of the U.S. (Salisbury beach, MA and Hampton beach, NH). A simple sampling tool was used to collect beach sand from depth intervals of 0-5 cm and 5-10 cm, respectively. The samples were sieved to give three size fractions: coarse (>1.2 mm), intermediate (100 μm-1.2 mm), and fine (1.2 μm-100 μm) particles. Following density separation and wet peroxide oxidation, a low-temperature solvent extraction protocol involving 2-chlorophenol was used to extract polyester (PET), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC). The extract was analyzed using Py-GC-MS for the respective polymers, while the solid residue was pyrolyzed separately for polyethylene (PE) and polypropylene (PP). The one-step solvent extraction method significantly simplified the sample matrix and improved the sensitivity of analysis. Among the samples, PET was detected in greater quantities in the fine fraction than in the intermediate size fraction, and PET fine particles were located predominantly in the surface sand. Similar to PET, PS was detected at higher mass concentrations in the fine particles in most samples. These results underscore the importance of beach environment for plastic fragmentation, where a combination of factors including UV irradiation, mechanical abrasion, and water exposure promote plastic breakdown. Surface accumulation of fine plastic particles may also be attributed to transport of microplastics through wind and tides. The proposed sample treatment and analysis methods may allow sensitive and quantitative measurements of size or depth-related distribution patterns of microplastics in complex environmental media.

Decades of monitoring plastic pollution in seabirds in Canada: Spatial, temporal, and methodological insights

Plastic ingestion by seabirds is an increasing issue worldwide, yet species can vary in ingestion based on ecological and morphological differences. This provokes the ecological question of which species are better suited to monitor plastic ingestion across regions and time. In Canada, we examined plastic ingestion in sympatric northern fulmars (Fulmarus glacialis), black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and black guillemots (Cepphus grylle). Here, we present new data and compare to historical work to inform plastic pollution monitoring in Canada. In 2021, 51 % of fulmars, 7 % of kittiwakes and 7 % of murres contained plastic, whereas guillemots had no pieces >1 mm. Regardless of the methods used to collect and process samples, fulmars continue to have low levels of ingestion compared to the European Arctic, but high levels compared to other species in the Canadian Arctic, emphasizing their continued utility as a monitoring tool for plastic pollution in Canada.

Abundance of Marine Macrodebris on the Northern Coast of Jaffna Peninsula, Sri Lanka

Marine plastic debris has emerged as a pressing concern along the northern coast of Jaffna, Sri Lanka, posing a significant threat to marine resources. A preliminary study was conducted to investigate the abundance and characteristics of marine plastic debris at four major fish landing sites in the northern coast of Jaffna, using the Clean Coast Index (CCI) and Plastic Abundance Index (PAI). The results revealed that the average abundance of marine debris and plastic debris were 1.71 ± 0.42 items/m2 and 1.66 ± 0.57 items/m2, respectively. The most common types of plastic debris represented plastic rope and net pieces (23.2%), followed by unidentified weathered plastic fragments (16.7%), beverage bottles (16.2%), bottle caps and lids (13%), and styrofoam (14.1%). The recognized sources of plastic debris were mainly fishing-based activities, recreation activities, transboundary sources, and unidentified sources. The fish landing sites were classified as exceptionally polluted, with a CCI exceeding 10 and a PAI value exceeding 8. Myliddy had the highest debris density, indicating substantial pollution levels, followed by Point Pedro, Mathagal, and Valveddithurai. These findings underscore the urgency of establishing a comprehensive plastic waste management framework for the northern coast of Jaffna and devising strategies to address buoyant debris within the northern Indian Ocean. Furthermore, this study carries significant implications for the local marine ecosystem, coastal communities, and Sri Lanka's broader environmental policies and practices.

Atmospheric deposition of microplastics at a western China metropolis: Relationship with underlying surface types and human exposure

The issue of atmospheric microplastic (AMP) contamination is gaining increasing attention, yet the influencing factors and human exposure are not well-understood. In this study, atmospheric depositions were collected in the megacity of Chengdu, China, to investigate the pollution status and spatial disparities in AMP distribution. The relationship between AMP abundance and underlying surface types was then analyzed with the aid of back trajectory simulation. Additionally, a probabilistic estimation of human exposure to AMP deposition during outdoor picnics was provided, followed by the calculation of AMP loading into rivers. Results revealed that the mean deposition flux ranged within 207.1-364.0 N/m2/d (14.17-33.75 μg/m2/d), with significantly larger AMP abundance and sizes in urban compared to rural areas. Areas of compact buildings played an important role in contributing to both fibrous and non-fibrous AMP contamination from urban to rural areas, providing new insight into potential sources of pollution. This suggests that appropriate plastic waste disposal in compact building areas should be prioritized for controlling AMP pollution. Besides, the median ingestion of deposited AMPs during a single picnic was 34.9 N/capita/hour (3.03 × 10-3 μg/capita/hour) for urban areas and 17.8 N/capita/hour (7.74 × 10-4 μg/capita/hour) for suburbs. Furthermore, the worst-case scenario of AMPs loading into rivers was investigated, which could reach 170.7 kg in summertime Chengdu. This work could contribute to a better understanding of the status of AMP pollution and its sources, as well as the potential human exposure risk.

Photoreforming of Microplastics: Challenges and Opportunities for Sustainable Environmental Remediation

Plastics are widely used in daily lives, but unfortunately, their inadequate recycling practices have led to the accumulation of microplastics in the environment, posing a threat to public health. The existing methods for treating microplastics are energy-intensive and environmentally damaging. In this context, photoreforming has emerged as a sustainable solution to address the microplastic crisis by simultaneously recycling them into value-added chemicals. This review presents a comprehensive overview of the application of photoreforming for upcycling microplastic. The underlying mechanisms of photoreforming reaction are discussed, followed by the exploration of recent advancements and innovative strategies in photoreforming techniques with particular emphasis on their real-world applications and potential for large-scale implementation. Also, critical factors influencing the efficiency of microplastic photoreforming are identified, providing guidance for further research and optimization.

A green approach to nanoplastic detection: SERS with untreated filter paper for polystyrene nanoplastics

Plastic pollution at the nanoscale continues to pose adverse effects on environmental sustainability and human health. However, the detection of nanoplastics (NPLs) remains challenging due to limitations in methodology and instrumentation. Herein, a "green approach" for surface-enhanced Raman spectroscopy (SERS) was exploited to detect polystyrene nanospheres (PSNSs) in water, employing untreated filter paper and a simple syringe-filtration set-up. This SERS protocol not only enabled the filtration of nano-sized PSNSs, which are smaller than the pore size of the ordinary filter paper, but also offered SERS enhancement by utilizing quasi-spherical-shaped silver nanoparticles (AgNPs) as the SERS-active substrate. The filtering of NPLs was accomplished by adding an aggregating agent to the nanoparticle mixture, which caused the aggregation of NPLs and AgNPs, resulting in a larger cluster and more hot spots for SERS detection. The optimal aggregating agent and its concentration, as well as the volume ratio between the AgNPs and NPLs, were also optimized. This SERS method successfully detected and quantified PSNSs of various sizes (i.e., 100, 300, 460, 600, and 800 nm) down to a limit of detection (LOD) of about 0.31 μg mL-1. The method was also validated against the presence of several interferents (i.e., salts, sugars, amino acids, and surfactants) and was proven practical, as evidenced by the detection of 800nm PSNSs in drinking and tap water (LODs of 1.47 and 1.55 μg mL-1, respectively).

Environmental fate of microplastics in high-altitude basins: the insights into the Yarlung Tsangpo River Basin

Microplastics (MPs) have been found in remote high-altitude areas, but the main source and migration process remained unclear. This work explored the characteristics and potential sources of MPs in the Yarlung Tsangpo River Basin. The average abundances of MPs in water, sediment, and soil samples were 728.26 ± 100.53 items/m3, 43.16 ± 5.82 items/kg, and 61.92 ± 4.29 items/kg, respectively, with polypropylene and polyethylene as the main polymers. The conditional fragmentation model revealed that the major source of MPs lower than 4000 m was human activities, while that of higher than 4500 m was atmospheric deposition. Community analysis was further conducted to explore the migration process and key points of MPs among different compartments in the basin. It was found that Lhasa (3600 m) and Shigatse (4100 m) were vital sources of MPs inputs in the midstream and downstream, respectively. This work would provide new insights into the fate of MPs in high-altitude areas.

Detrimental consequences of micropolymers associated plasticizers on endocrinal disruption

The prevalence of polymer usage in everyday activities has emerged as a detriment to both human life and the environment. A large number of studies describe severe impacts of micropolymers (MP) and nanopolymers (NP) on various organ systems, including the endocrine system. Additionally, plasticizers utilized as additives have been identified as endocrine-disrupting chemicals (EDCs). MP/NP, along with associated plasticizers, affect principal signalling pathways of endocrine glands such as the pituitary, thyroid, adrenal, and gonads, thereby disrupting hormone function and metabolic processes crucial for maintaining homeostasis, fertility, neural development, and fetal growth. This review delves into the sources, distribution, and effects of micropolymers, nanopolymers, and associated plasticizers acting as EDCs. Furthermore, it provides a detailed review of the mechanisms underlying endocrine disruption in relation to different types of MP/NP.

Polyethylene Terephthalate Microplastics Generated from Disposable Water Bottles Induce Interferon Signaling Pathways in Mouse Lung Epithelial Cells

Microplastics (MPs) are present in ambient air in a respirable size fraction; however, their potential impact on human health via inhalation routes is not well documented. In the present study, methods for a lab-scale generation of MPs from regularly used and littered plastic articles were optimized. The toxicity of 11 different types of MPs, both commercially purchased and in-lab prepared MPs, was investigated in lung epithelial cells using cell viability, immune and inflammatory response, and genotoxicity endpoints. The underlying mechanisms were identified by microarray analysis. Although laborious, the laboratory-scale methods generated a sufficient quantity of well characterized MPs for toxicity testing. Of the 11 MPs tested, the small sized polyethylene terephthalate (PETE) MPs prepared from disposable water bottles induced the maximum toxicity. Specifically, the smaller size PETE MPs induced a robust activation of the interferon signaling pathway, implying that PETE MPs are perceived by cells by similar mechanisms as those employed to recognize pathogens. The PETE MPs of heterogenous size and shapes induced cell injury, triggering cell death, inflammatory cascade, and DNA damage, hallmark in vitro events indicative of potential in vivo tissue injury. The study establishes toxicity of specific types of plastic materials in micron and nano size.

Characteristics, sources and potential ecological risk of atmospheric microplastics in Lhasa city

Atmospheric microplastics are important contributors to environmental contamination in aquatic and terrestrial systems and pose potential ecological risks. However, studies on atmospheric microplastics are still limited in urban regions of the Tibetan Plateau, a sentinel region for climate and environmental change under a warming climate. In this study, the occurrence and potential ecological risk of atmospheric microplastics were investigated in samples of suspended atmospheric microplastics collected in Lhasa city during the Tibetan New Year in February 2023. The results show that the average abundance of atmospheric microplastics in Lhasa was 7.15 ± 2.46 MPs m-3. The sizes of the detected microplastics ranged from 20.34 to 297.18 μm, approximately 87% of which were smaller than 100 μm. Fragmented microplastics (95.76%) were the dominant shape, followed by fibres (3.75%) and pellets (0.49%). The primary polymer chemical components identified were polyamide (68.73%) and polystyrene (16.61%). The analysis of meteorological data and the backwards trajectory model indicated the air mass in Lhasa mainly controlled by westwards, and the atmospheric microplastics mainly originated from long-distance atmospheric transport. The potential ecological risk index assessment revealed that the atmospheric microplastic pollution in Lhasa was relatively low. This study provides valuable insights and a scientific foundation for future research on the prevention and control of atmospheric microplastic pollution in Lhasa and other ecologically sensitive cities.

Microplastic Particles and Fibers in Seasonal Ice of the Northern Baltic Sea

Microplastic pollution is a pervasive issue, with remarkably high concentrations observed even in the most remote locations such as Arctic sea ice and snow. The reason for such large microplastic abundances in sea ice is still speculative and applies mainly to saline or freshwater conditions. In this study, we investigated seasonal ice core samples collected in March 2021 from the northern Baltic Sea (Gulf of Bothnia) for their microplastic distributions. The Baltic Sea is characterized by low salinity and can be ice-covered for up to six months annually. Microplastics were analyzed in the melted ice samples using an adsorption technique and Raman microscopy to identify their abundances, colors, shapes, and sizes to calculate their masses. Due to the strong dynamic of the ice layer and the repeated melting and freezing processes during the ice formation, no discernible trends in microplastic abundances, masses, or polymer types were observed throughout the ice core length. The average microplastic abundance (±SD) in the Baltic Sea ice was determined to be 22.3 ± 8.6 N L-1, with 64.9% of the particles exhibiting a particulate shape and 35.1% having a fibrous shape. The most prevalent polymer type was polyethylene terephthalate (PET), accounting for 44.4% of all polymers. This is likely due to the high proportion of PET fibers (93.8%). The majority of particle-shaped microplastics were identified as polyethylene (PE; 37.2%), followed by PET (17.2%), polyvinyl chloride (PVC; 15.9%), and polypropylene (PP; 15.9%). No correlations were found between microplastic concentrations and proximity to land, cities, industries, or rivers, except for PP mass concentrations and particle sizes, which correlated with distances to industries in Luleå, Sweden.

A Valuable Source of Promising Extremophiles in Microbial Plastic Degradation

Plastics have accumulated in open environments, such as oceans, rivers, and land, for centuries, but their effect has been of concern for only decades. Plastic pollution is a global challenge at the forefront of public awareness worldwide due to its negative effects on ecological systems, animals, human health, and national economies. Therefore, interest has increased regarding specific circular economies for the development of plastic production and the investigation of green technologies for plastic degradation after use on an appropriate timescale. Moreover, biodegradable plastics have been found to contain potential new hazards compared with conventional plastics due to the physicochemical properties of the polymers involved. Recently, plastic biodegradation was defined as microbial conversion using functional microorganisms and their enzymatic systems. This is a promising strategy for depolymerizing organic components into carbon dioxide, methane, water, new biomass, and other higher value bioproducts under both oxic and anoxic conditions. This study reviews microplastic pollution, the negative consequences of plastic use, and the current technologies used for plastic degradation and biodegradation mediated by microorganisms with their drawbacks; in particular, the important and questionable role of extremophilic multi-enzyme-producing bacteria in synergistic systems of plastic decomposition is discussed. This study emphasizes the key points for enhancing the plastic degradation process using extremophiles, such as cell hydrophobicity, amyloid protein, and other relevant factors. Bioprospecting for novel mechanisms with unknown information about the bioproducts produced during the plastic degradation process is also mentioned in this review with the significant goals of CO2 evolution and increasing H2/CH4 production in the future. Based on the potential factors that were analyzed, there may be new ideas for in vitro isolation techniques for unculturable/multiple-enzyme-producing bacteria and extremophiles from various polluted environments.

Airborne transboundary microplastics-A Swirl around the globe

Microplastics are persistent pollutants discovered and extensively researched in marine, freshwater, and terrestrial ecosystems but have yet to receive attention in an atmospheric context. Although recent reports stated the presence of microplastics in the air, their global existence and distribution are not critically discussed to date. This review aimed to investigate the current status of research on atmospheric microplastics through bibliometric analysis and by comparing and summarising published research on global distribution. The review also provides a summary of methods that have been used to collect samples, identify microplastics, quantify their occurrence, and determine their transport mechanisms. The bibliometric analysis revealed that atmospheric microplastic studies predominantly originated in China. Clothing, vehicle, and tire materials were the major primary sources while house furniture, construction materials, landfills, urban dust, plastic recycling processes, and agricultural sludge were precursor secondary sources. Polyethylene, polypropylene, and polyethylene terephthalate microfibres have most frequently found in indoor and outdoor atmospheres. Level of urbanization and temporal or spatial distributions governs the fate of airborne microplastics, however, the knowledge gap in the retention and circulation of microplastics through the atmosphere is still large. Many challenges and limitations were identified in the methods used, presentation of data, aerodynamic processes facilitating atmospheric transport, and scarcity of research in spatially and temporally diverse contexts. The review concluded that there was a greater need for globalization of research, methods and data standardization, and emphasizes the potential for future research with atmospheric transportation modelling and thermochemical analysis.

Transitioning to Microplastic-Free Seed Coatings: Challenges and Solutions

This review addresses the issue of replacing manufactured microplastics in seed coatings used in agriculture. Firstly, it focuses on the policy and regulatory actions taken on microplastics at a global level. There is no consensus within the scientific community on the definition of a microplastic and, more generally, on the classification of plastic debris. Nevertheless, several decision schemes have been proposed in an attempt to define the notion of microplastics. The different criteria relevant to this definition, such as the size, physical state, chemical structure, origin, and persistence of microplastics, are discussed, with a comparison being made between the REACH regulation and the scientific literature. Seed production and processing are also discussed, with the functions of seed coatings being explained in order to gain a better understanding of the properties to be considered in a substitution strategy for currently used microplastics. The main challenges are multiple; substitutes must provide the same performance as microplastics: (i) improving the adherence of the treatment to the seed, (ii) distributing the treatment more evenly over the seed, (iii) reducing the amount of dust-off when handling treated seed, and (iv) improving the seed flowability, which is particularly important during the sowing stage, all while preserving the physiological properties of the seed. Substitute polymers are proposed according to the desired performance and functional properties: two main chemical families of biopolymers were identified in the literature: polysaccharides and proteins. Among them, 13 and 6 polymers, respectively, complied with REACH regulation, demonstrating adhesion, dust reduction performances, and preservation of seed physiological quality in particular. This work aims to guide future studies on microplastic substitution in seed coatings, and to highlight research needs in this area. It is based on an analysis and discussion of the literature, identifying and listing potential substitutes.

Physiological and transcriptomic analysis reveals the toxicological mechanisms of polystyrene micro- and nano-plastics in Chlamydomonas reinhardtii

With the accumulation of plastic waste in the environment, the toxicity of micro- and nano-plastics (MNPs) to microalgae has attracted increasing attention. However, the underlying toxic mechanisms of MNPs remain to be elucidated. In this study, we synthesized micro- and nano-scale of polystyrene MNPs (PS MNPs) to investigate their toxicity and toxic mechanisms in Chlamydomonas reinhardtii. We found that PS MNPs significantly inhibit the production of photosynthetic pigments and increase soluble protein content. The detailed analysis of results shows that both materials affect photosynthetic efficiency by damaging the donor side, reaction center, and electron transfer of photosystem II. Moreover, compared to PS MPs, PS NPs have a greater negative impact on algal cells. Analyzing the transcriptome of cells suggests that the most sensitive metabolic pathways in response to PS MNPs involve oxidative phosphorylation, biosynthesis of secondary metabolites, and photosynthesis. Especially, genes related to photosynthesis and oxidative phosphorylation showed significant changes in expression after exposure to PS MNPs. This study provided molecular-level insights into the toxic mechanisms of PS MNPs on microalgae.

Heteroaggregation kinetics of nanoplastics and soot nanoparticles in aquatic environments

Heteroaggregation between polystyrene nanoplastics (PSNPs) and soot nanoparticles (STNPs) in aquatic environments may affect their fate and transport. This study investigated the effects of particle concentration ratio, electrolytes, pH, and humic acid on their heteroaggregation kinetics. The critical coagulation concentration (CCC) ranked CCCPSNPs > CCCPSNPs-STNPs > CCCSTNPs, indicating that heteroaggregation rates fell between homoaggregation rates. In NaCl solution, as the PSNPs/STNPs ratio decreased from 9/1 to 3/7, heteroaggregation rate decreased and CCCPSNPs-STNPs increased from 200 to 220 mM due to enhanced electrostatic repulsion. Outlier was observed at PSNPs/STNPs= 1/9, where CCCPSNPs-STNPs= 170 mM and homoaggregation of STNPs dominated. However, in CaCl2 solution where calcium bridged with STNPs, heteroaggregation rate increased and CCCPSNPs-STNPs decreased from 26 to 5 mM as the PSNPs/STNPs ratio decreasing from 9/1 to 1/9. In composite water samples, heteroaggregation occurred only at estuarine and marine salinities. Acidic condition promoted heteroaggregation via charge screening. Humic acid retarded or promoted heteroaggregation in NaCl or CaCl2 solutions by steric hindrance or calcium bridging, respectively. Other than van der Waals attraction and electrostatic repulsion, heteroaggregation was affected by steric hindrance, hydrophobic interactions, π - π interactions, and calcium bridging. The results highlight the role of black carbon on colloidal stability of PSNPs in aquatic environments.

Aging and adsorption behavior of PP-MPs for methylene blue and tetracycline in unitary and binary systems

The omnipresence of microplastics (MPs) around the world has attracted extensive attention in the past decade with more focuses on the interactions of standard MPs without additives in regular shapes and individual pollutant, whereas the actual MPs containing various additives in irregular shapes and complex pollutants are often co-occurrence in the environments. In this paper, the adsorption performance of disposable polypropylene (PP) cups-based MPs subjected to ultraviolet irradiation was investigated in unitary and binary water matrices. The surface characteristics were analyzed and the experimental data of adsorption were fitted by various kinetic and isotherm models, and the results indicated that more cracks and oxygen-containing functional groups with decreased hydrophobicity were produced with aging, and electrostatic attraction and hydrogen bonding dominated methylene blue (MB) and tetracycline (TC) capture in the individual system. Moreover, pseudo-second order kinetic model better described the adsorption processes. In the binary system, the co-existence of TC promoted MB uptake, while the presence of MB inhibited TC capture. In addition, TC adsorption was enhanced by Ca2+, maybe due to its complexation effect, while the presence of mono- and divalent inorganic salts inhibited MB capture. This research provides useful insights for the fate of PP-MPs and organic pollutants in the complex environments.

Riverbed depth-specific microplastics distribution and potential use as process marker

Riverbed sediments have been identified as temporary and long-term accumulation sites for microplastic particles (MPs), but the relocation and retention mechanisms in riverbeds still need to be better understood. In this study, we investigated the depth-specific occurrence and distribution (abundance, type, and size) of MPs in river sediments down to a depth of 100 cm, which had not been previously investigated in riverbeds. In four sediment freeze cores taken for the Main River (Germany), MPs (≥ 100 µm) were detected using two complementary analytical approaches (spectroscopy and thermoanalytical) over the entire depth with an average of 21.7 ± 21.4 MP/kg or 31.5 ± 28.0 mg/kg. Three vertical trends for MP abundance could be derived, fairly constant in top layers (0-‍30 cm), a decrease in middle layers (30-60 cm), and a strong increase in deep layers (60-100 cm). The dominant polymer types were polyethylene (PE), polypropylene (PP), and polystyrene (PS). Polyethylene terephthalate (PET) and PP were also found in deep layers, albeit with the youngest age of earliest possible occurrence (EPO age of 1973 and 1954). The fraction of smaller-sized MPs (100-500 µm) increased with depth in shallow layers, but the largest MPs (> 1 mm) were detected in deep layers. Based on these findings, we elucidate the relationship between the depth-specific MP distribution and the prevailing processes of MP retention and sediment dynamics in the riverbed. We propose some implications and offer an initial conceptual approach, suggesting the use of microplastics as a potential environmental process tracer for driving riverbed sediment dynamics.

Environmental impact of microplastics and potential health hazards

Microscopic plastic (microplastic) pollutants threaten the earth's biodiversity and ecosystems. As a result of the progressive fragmentation of oversized plastic containers and products or manufacturing in small sizes, microplastics (particles of a diameter of 5 mm with no lower limit) are used in medicines, personal care products, and industry. The incidence of microplastics is found everywhere in the air, marine waters, land, and even food that humans and animals consume. One of the greatest concerns is the permanent damage that is created by plastic waste to our fragile ecosystem. The impossibility of the complete removal of all microplastic contamination from the oceans is one of the principal tasks of our governing body, research scientists, and individuals. Implementing the necessary measures to reduce the levels of plastic consumption is the only way to protect our environment. Cutting off the plastic flow is the key remedy to reducing waste and pollution, and such an approach could show immense significance. This review offers a comprehensive exploration of the various aspects of microplastics, encompassing their composition, types, properties, origins, health risks, and environmental impacts. Furthermore, it delves into strategies for comprehending the dynamics of microplastics within oceanic ecosystems, with a focus on averting their integration into every tier of the food chain.

Aerosolization of micro- and nanoplastics via sea spray: Investigating the role of polymer type, size, and concentration, and potential implications for human exposure

Micro- and nanoplastics (MNPs) can enter the atmosphere via sea spray aerosols (SSAs), but the effects of plastic characteristics on the aerosolization process are unclear. Furthermore, the importance of the transport of MNPs via these SSAs as a possible new exposure route for human health remains unknown. The aim of this study was two-fold: (1) to examine if a selection of factors affects aerosolization processes of MNPs, and (2) to estimate human exposure to MNPs via aerosols inhalation. A laboratory-based bubble bursting mechanism, simulating the aerosolization process at sea, was used to investigate the influence of MNP as well as seawater characteristics. To determine the potential human exposure to microplastics via inhalation of SSAs, the results of the laboratory experiments were extrapolated to the field based on sea surface microplastic concentrations and the volume of inhaled aerosols. Enrichment seemed to be influenced by MNP size, concentration and polymer type. With higher enrichment for smaller particles and denser polymers. Experiments with different concentrations showed a larger range of variability but nonetheless lower concentrations seemed to result in higher enrichment, presumably due to lower aggregation. In addition to the MNP characteristics, the type of seawater used seemed to influence the aerosolization process. Our human exposure estimate to microplastic via inhalation of sea spray aerosols shows that in comparison with reported inhaled concentrations in urban and indoor environments, this exposure route seems negligible for microplastics. Following the business-as-usual scenario on plastic production, the daily plastic inhalation in coastal areas in 2100 is estimated to increase but remain far below 1 particle per day. This study shows that aerosolization of MNPs is a new plastic transport pathway to be considered, but in terms of human exposure it seems negligible compared to other more important sources of MNPs, based on current reported environmental concentrations.

Biomonitoring of airborne microplastics and microrubbers in Shiraz, Iran, using lichens and moss

HIGHLIGHTS

Microplastics (MPs) and microrubbers (MRs) determined in lichens and mosses around Shiraz. In lichens, MPs mainly thin fibres up to 1 MP g-1; MRs were < 0.1 MP g-1. In mosses, abundances were similar but with a greater fraction of larger, non-fibrous particles. Larger MPs and MRs decreased in abundance with distance and elevation from Shiraz. Around Shiraz, the common moss, Grimmia critina, would be the most suitable biomonitor. Lichens and mosses have been employed as biomonitors of atmospheric particulate pollutants, like metals and industrial solids, for many decades. Here, we evaluated the potential of nine species of crustose and foliose lichens and a widely distributed moss (Grimmia critina) to act as biomonitors of airborne microplastics (MPs) and microrubbers (MRs). About 200 lichens and 40 mosses were sampled across different altitudinal transects in the vicinity of Shiraz City, southwest Iran, and MPs and MRs were quantified and characterised after sample peroxidation. In most species of lichen, MP and MR abundance overall was < 1 g-1 and < 0.1 g-1, respectively, and the majority of plastics were fibres of < 10 µm in diameter and < 1000 µm in length. Respective weight normalised abundances of MPs and MRs were similar in G. critina, but there were greater proportions of both larger (> 1000 µm) and non-fibrous particles among the MPs. In both lichens and moss, there was a greater number of larger MPs and MRs at locations closest to and at the same elevation as Shiraz than at more distant and elevated locations, suggesting an inverse relationship between particle size and distance travelled. Among the lichens, members of the genus Acarospora, with their areolated form, appeared to act as the most suitable biomonitors for MPs and MRs. Overall, however, the wide distribution of the moss, G. crinita, and its ability to intercept and accumulate a broader range of sizes and shapes of MPs and MRs make this species a better choice, at least in the type of environment studied.

Plastiome: Plastisphere-enriched mobile resistome in aquatic environments

Aquatic microplastics (MPs) act as reservoirs for microbial communities, fostering the formation of a mobile resistome encompassing diverse antibiotic (ARGs) and biocide/metal resistance genes (BMRGs), and mobile genetic elements (MGEs). This collective genetic repertoire, referred to as the "plastiome," can potentially perpetuate environmental antimicrobial resistance (AMR). Our study examining two Japanese rivers near Tokyo revealed that waterborne MPs are primarily composed of polyethylene and polypropylene fibers and sheets of diverse origin. Clinically important genera like Exiguobacterium and Eubacterium were notably enriched on MPs. Metagenomic analysis uncovered a 3.46-fold higher enrichment of ARGs on MPs than those in water, with multidrug resistance genes (MDRGs) and BMRGs prevailing, particularly within MPs. Specific ARG and BMRG subtypes linked to resistance to vancomycin, beta-lactams, biocides, arsenic, and mercury showed selective enrichment on MPs. Network analysis revealed intense associations between host genera with ARGs, BMRGs, and MGEs on MPs, emphasizing their role in coselection. In contrast, river water exhibited weaker associations. This study underscores the complex interactions shaping the mobile plastiome in aquatic environments and emphasizes the global imperative for research to comprehend and effectively control AMR within the One Health framework.

The impact of microplastics polystyrene on the microscopic structure of mouse intestine, tight junction genes and gut microbiota

Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1, Claudin-2, Claudin-15, and Occludin, in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae.

Multi-method analysis of microplastic distribution by flood frequency and local topography in Rhine floodplains

Rivers are important transport pathways for microplastics into the ocean, but they can also be potential sinks due to microplastic deposition in the sediments of the river bed and adjacent floodplains. In particular, floods can (re)mobilise microplastics from sediments and floodplains, (re)deposit and relocate them depending on the floodplain topography. The knowledge about fluvial microplastic input to floodplains, their spatial distribution and their fate in floodplain soils is limited. To investigate this topic, we sampled soil at a depth of 5-20 cm along three transects in three different Rhine floodplains. We analysed the soil samples in tandem with pyrolysis GC/MS and ATR- & μ-FPA-FTIR for their microplastic abundance and mass concentrations. To study the influence of flood frequency on the microplastic abundance in the three floodplains, we fitted a hydrodynamic flood model (MIKE 21, DHI, Hørsholm, Denmark) and related the results to the respective spatial microplastic distribution. We found similar microplastic distribution patterns in each floodplain. The highest microplastic abundance (8516-70,124 microplastics kg-1) and mass concentration (46.2-141.6 mg kg-1) were consistently found in the farthest transects from the Rhine in a topographical depression. This microplastic distribution pattern is detectable with both, pyrolysis GC/MS and FTIR. The strongest correlation between the results of both methods was found for small, abundant microplastic particles. Our results suggest that the spatial distribution of microplastics in floodplains is related to the combination of flood frequency and local topography, that ought to be explicitly considered in future studies conducted in floodplains. Finally, our results indicate that pyrolysis GC/MS and FTIR data are comparable under certain conditions, which may help in the decision for the analytical method and sampling design in future studies.

Toxicity effects and mechanism of micro/nanoplastics and loaded conventional pollutants on zooplankton: An overview

Micro/nanoplastics in aquatic environments is a noteworthy environmental problem. Zooplankton, an important biological group in aquatic ecosystems, readily absorb micro/nanoplastics and produce a range of toxic endpoints due to their small size. This review summarises relevant studies on the effects of micro/nanoplastics on zooplankton, including combined effects with conventional pollutants. Frequently reported adverse effects include acute/chronic lethal effects, oxidative stress, gene expression, energetic homeostasis, and growth and reproduction. Obstruction by plastic entanglement and blockage is the physical mechanism. Genotoxicity and cytotoxicity are molecular mechanisms. Properties of micro/nanoplastics, octanol/water partition coefficients of conventional pollutants, species and intestinal environments are important factors influencing single and combined toxicity. Selecting a wider range of micro/nanoplastics, focusing on the aging process and conducting field studies, adopting diversified zooplankton models, and further advancing the study of mechanisms are the outstanding prospects for deeper understanding of impacts of micro/nanoplastics on aquatic ecosystem.

Developmental and biochemical markers of the impact of pollutant mixtures under the effect of Global Climate Change

This study investigates the combined impact of microplastics (MP) and Chlorpyriphos (CPF) on sea urchin larvae (Paracentrotus lividus) under the backdrop of ocean warming and acidification. While the individual toxic effects of these pollutants have been previously reported, their combined effects remain poorly understood. Two experiments were conducted using different concentrations of CPF (EC10 and EC50) based on previous studies from our group. MP were adsorbed in CPF to simulate realistic environmental conditions. Additionally, water acidification and warming protocols were implemented to mimic future ocean conditions. Sea urchin embryo toxicity tests were conducted to assess larval development under various treatment combinations of CPF, MP, ocean acidification (OA), and temperature (OW). Morphometric measurements and biochemical analyses were performed to evaluate the effects comprehensively. Results indicate that combined stressors lead to significant morphological alterations, such as increased larval width and reduced stomach volume. Furthermore, biochemical biomarkers like acetylcholinesterase (AChE), glutathione S-transferase (GST), and glutathione reductase (GRx) activities were affected, indicating oxidative stress and impaired detoxification capacity. Interestingly, while temperature increase was expected to enhance larval growth, it instead induced thermal stress, resulting in lower growth rates. This underscores the importance of considering multiple stressors in ecological assessments. Biochemical biomarkers provided early indications of stress responses, complementing traditional growth measurements. The study highlights the necessity of holistic approaches when assessing environmental impacts on marine ecosystems. Understanding interactions between pollutants and environmental stressors is crucial for effective conservation strategies. Future research should delve deeper into the impacts at lower biological levels and explore adaptive mechanisms in marine organisms facing multiple stressors. By doing so, we can better anticipate and mitigate the adverse effects of anthropogenic pollutants on marine biodiversity and ecosystem health.

What are the global patterns of microplastic ingestion by fish? A scientometric review

The billions of tons of plastic released into the environment mostly fragment into smaller particles that reach rivers and oceans, posing toxicity risks to aquatic organisms. As fish serve as excellent environmental indicator organisms, this study aims to comprehensively review and quantify published data regarding the abundance of microplastics (MPs) ingested by fish through scientometric analysis. Systematic analysis reveals that global aquatic ecosystems are contaminated by MPs, with the characteristics of these contaminants stemming from inadequate disposal management practices. The abundance of MPs was recorded in several fish species, notably Cyprinus carpio in natural environments and Danio rerio in controlled environments. According to the surveyed studies, laboratory experiments do not accurately represent the conditions found in natural environments. The results suggest that, in natural environments, the predominant colors of MPs are blue, black, and red. Fibers emerged as the most prevalent type, with polyethylene (PE) and polypropylene (PP) being the most frequently identified chemical compositions. On the other hand, laboratory studies showed that the spheres and fragments ingested were predominantly polystyrene (PS) green, followed by the colors blue and red. This discrepancy complicates drawing accurate conclusions regarding the actual effects of plastic particles on aquatic biota. Given the enduring presence of plastic in the environment, it is imperative to consider and implement environmental monitoring for effective, long-term management.

Snow dumping station - A considerable source of tyre wear, microplastics, and heavy metal pollution

Snow dumping stations can be a hotspots for pollutants to water resources. However, little is known about the amount of microplastics including tyre wear particles transported this way. This study investigated microplastics and metals in snow from four snow dumping stations in Riga, Latvia, a remote site (Gauja National Park), and a roof top in Riga. Microplastics other than tyre wear particles were identified with Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) (>500 µm) and focal plane array based micro-Fourier Transform Infrared (FPA-µFTIR) imaging (10-500 µm), tyre wear particles by Pyrolysis Gas Chromatography-Mass Spectroscopy (Py-GC-MS), and total metals by Inductively Coupled Plasma with Optical Emission Spectroscopy (ICP-OES). Microplastics detected by FTIR were quantified by particle counts and their mass estimated, while tyre wear particles were quantified by mass. The concentrations varied substantially, with the highest levels in the urban areas. Microplastic concentrations measured by FTIR ranged between 26 and 2549 counts L-1 of melted snow with a corresponding estimated mass of 19-573 µg/L. Tyre wear particles were not detected at the two reference sites, while other sites held 44-3026 µg/L. Metal concentrations varied several orders of magnitude with for example sodium in the range 0.45-819.54 mg/L and cadmium in the range 0.05-0.94 µg/L. Correlating microplastic measured by FTIR to metal content showed a weak to moderate correlation. Tyre wear particles, however, correlated strongly to many of the metals. The study showed that snow can hold considerable amounts of these pollutants, which upon melting and release of the meltwater to the aquatic environment could impact receiving waters.

Characteristics and adsorption behavior of typical microplastics in long-term accelerated weathering simulation

Microplastics can function as carriers in the environment, absorbing various toxins and spreading to diverse ecosystems. Toxins accumulated in microplastics have the potential to be re-released, posing a threat. In this study, two typical plastics, namely polyethylene (PE) and polystyrene (PS), along with the degradable plastic poly(butylene adipate-co-terephthalate) (PBAT), were subjected to a long-term ultraviolet alternating weathering experiment. The study investigated the variations in the weathering process and pollutant adsorption of microplastics of different particle sizes. Furthermore, the adsorption capacity of microplastics for various pollutants was assessed. The findings indicate that particle size significantly influences weathering, leading to variations in adsorption capacity. The weathered PE displays a higher adsorption capacity for azo dyes. Additionally, the adsorption capacity of PBAT for neutral red is double that of antibiotics. Importantly, the maximum adsorption capacity of PBAT for pollutants after aging is approximately 10 times greater than that of PE. Consequently, degradable plastics undergoing weathering in the natural environment may pose a higher ecological risk than traditional plastics.

Microplastic-antifouling paint particle contamination alters microbial communities in surrounding marine sediment

Paint used to coat surfaces in aquatic environments often contain biocides to prevent biofouling, and as these coatings degrade, antifouling paint particles (APPs) end up in aquatic, and especially marine, sediments. However, it is currently unclear what further influence APPs in the sediment have on biotic communities or processes. This study investigates how a variety of commercially-available APPs effect the marine microbial community by spiking different laboratory-manufactured APPs to sediment. Following exposure for 30 and 60 days, APPs caused a clear and consistent effect on the bacterial community composition as determined by 16S metabarcoding. This effect was strongest between 0 and 30 days, but continues to a lesser extent between 30 and 60 days. APPs appear to inhibit the highly diverse, but in general rarer, fraction of the community and/or select for specific community members to become more dominant. 71 antifouling-presence and 454 antifouling-absence indicator taxa were identified by indicator analysis. The difference in the level of classification in these two indicator groups was highly significant, with the antifouling-presence indicators having much higher percentage sequence identity to cultured taxa, while the antifouling-absence indicators appear to be made up of undescribed taxa, which may indicate that APPs act as a proxy for general anthropogenic influence or that APP contamination selects for taxa capable of being cultured. Given the clear and consistent effect APPs have on the surrounding sediment microbial community, further research into how APPs affect sediment functional processes and how such effects scale with concentration is recommended to better assess the wider consequences of these pollutants for marine biogeochemical cycles in the future. SYNOPSIS: Microplastic-paint particles are commonly found in marine sediment but little is known about how these, especially antifouling, paint particles affect sediment microbial communities. This study demonstrates that antifouling paint particles fundamentally alter sediment microbial communities.

Development of a New Aggregation Method to Remove Nanoplastics from the Ocean: Proof of Concept Using Mussel Exposure Tests

The overproduction and mismanagement of plastics has led to the accumulation of these materials in the environment, particularly in the marine ecosystem. Once in the environment, plastics break down and can acquire microscopic or even nanoscopic sizes. Given their sizes, microplastics (MPs) and nanoplastics (NPs) are hard to detect and remove from the aquatic environment, eventually interacting with marine organisms. This research mainly aimed to achieve the aggregation of micro- and nanoplastics (MNPs) to ease their removal from the marine environment. To this end, the size and stability of polystyrene (PS) MNPs were measured in synthetic seawater with the different components of the technology (ionic liquid and chitosan). The MPs were purchased in their plain form, while the NPs displayed amines on their surface (PS NP-NH2). The results showed that this technology promoted a significant aggregation of the PS NP-NH2, whereas, for the PS MPs, no conclusive results were found, indicating that the surface charge plays an essential role in the MNP aggregation process. Moreover, to investigate the toxicological potential of MNPs, a mussel species (M. galloprovincialis) was exposed to different concentrations of MPs and NPs, separately, with and without the technology. In this context, mussels were sampled after 7, 14, and 21 days of exposure, and the gills and digestive glands were collected for analysis of oxidative stress biomarkers and histological observations. In general, the results indicate that MNPs trigger the production of reactive oxygen species (ROS) in mussels and induce oxidative stress, making gills the most affected organ. Yet, when the technology was applied in moderate concentrations, NPs showed adverse effects in mussels. The histological analysis showed no evidence of MNPs in the gill's tissues.

Polystyrene nanoplastics mediate oxidative stress, senescence, and apoptosis in a human alveolar epithelial cell line

Background

Nanoplastics, an emerging form of pollution, are easily consumed by organisms and pose a significant threat to biological functions due to their size, expansive surface area, and potent ability to penetrate biological systems. Recent findings indicate an increasing presence of airborne nanoplastics in atmospheric samples, such as polystyrene (PS), raising concerns about potential risks to the human respiratory system.

Methods

This study investigates the impact of 800 nm diameter-PS nanoparticles (PS-NPs) on A549, a human lung adenocarcinoma cell line, examining cell viability, redox balance, senescence, apoptosis, and internalization. We also analyzed the expression of hallmark genes of these processes.

Results

We demonstrated that PS-NPs of 800 nm in diameter significantly affected cell viability, inducing oxidative stress, cellular senescence, and apoptosis. PS-NPs also penetrated the cytoplasm of A549 cells. These nanoparticles triggered the transcription of genes comprised in the antioxidant network [SOD1 (protein name: superoxide dismutase 1, soluble), SOD2 (protein name: superoxide dismutase 2, mitochondrial), CAT (protein name: catalase), Gpx1 (protein name: glutathione peroxidase 1), and HMOX1 (protein name: heme oxygenase 1)], senescence-associated secretory phenotype [Cdkn1a (protein name: cyclin-dependent kinase inhibitor 1A), IL1A (protein name: interleukin 1 alpha), IL1B (protein name: interleukin 1 beta), IL6 (protein name: interleukin 6), and CXCL8 (protein name: C-X-C motif chemokine ligand 8)], and others involved in the apoptosis modulation [BAX (protein name: Bcl2 associated X, apoptosis regulator), CASP3 (protein name: caspase 3), and BCL2 (protein name: Bcl2, apoptosis regulator)].

Conclusion

Collectively, this investigation underscores the importance of concentration (dose-dependent effect) and exposure duration as pivotal factors in assessing the toxic effects of PS-NPs on alveolar epithelial cells. Greater attention needs to be directed toward comprehending the risks of cancer development associated with air pollution and the ensuing environmental toxicological impacts on humans and other terrestrial mammals.

The triple exposure nexus of microplastic particles, plastic-associated chemicals, and environmental pollutants from a human health perspective

The presence of microplastics (MPs) is increasing at a dramatic rate globally, posing risks for exposure and subsequent potential adverse effects on human health. Apart from being physical objects, MP particles contain thousands of plastic-associated chemicals (i.e., monomers, chemical additives, and non-intentionally added substances) captured within the polymer matrix. These chemicals are often migrating from MPs and can be found in various environmental matrices and human food chains; increasing the risks for exposure and health effects. In addition to the physical and chemical attributes of MPs, plastic surfaces effectively bind exogenous chemicals, including environmental pollutants (e.g., heavy metals, persistent organic pollutants). Therefore, MPs can act as vectors of environmental pollution across air, drinking water, and food, further amplifying health risks posed by MP exposure. Critically, fragmentation of plastics in the environment increases the risk for interactions with cells, increases the presence of available surfaces to leach plastic-associated chemicals, and adsorb and transfer environmental pollutants. Hence, this review proposes the so-called triple exposure nexus approach to comprehensively map existing knowledge on interconnected health effects of MP particles, plastic-associated chemicals, and environmental pollutants. Based on the available data, there is a large knowledge gap in regard to the interactions and cumulative health effects of the triple exposure nexus. Each component of the triple nexus is known to induce genotoxicity, inflammation, and endocrine disruption, but knowledge about long-term and inter-individual health effects is lacking. Furthermore, MPs are not readily excreted from organisms after ingestion and they have been found accumulated in human blood, cardiac tissue, placenta, etc. Even though the number of studies on MPs-associated health impacts is increasing rapidly, this review underscores that there is a pressing necessity to achieve an integrated assessment of MPs' effects on human health in order to address existing and future knowledge gaps.