(Nano)plastics in the environment - Sources, fates and effects

Spatiotemporal variations, source apportionment, and cross-regional impacts of microplastics in surface seawater of Chinese Marginal Seas

Microplastics (MPs) are widely distributed as a global pollutant, with dynamic patterns driven by horizontal diffusion and vertical mixing in marine ecosystems across different hydrological seasons and regions. This study employed MATLAB for image processing and interactive operations to extract data from existing studies on the Chinese Marginal Seas conducted from 2016 to 2022, focusing on the distribution, sources, and transport processes of MPs. The results revealed that the Bohai Sea exhibited the highest pollution levels during both the rainy (9328.30 particles/m3) and dry (8665.80 particles/m3) seasons. The Yangtze River Estuary, the Pearl River Estuary, and the Bohai Bay are three hotspot regions that may significantly contribute to the enrichment of MPs in surrounding seas. The distance-similarity decay relationship indicated stronger correlations in the South China Sea and Bohai Sea during the rainy season, and in the East China Sea during the dry season. Derived from the analysis using the Positive Matrix Factorization model, it was found that, apart from the South China Sea where PE and PAN proportions were higher, PE and PP dominated the MP composition. Highly polluting and difficult-to-degrade industrial manufacturing and plastic packaging were identified as the primary sources, while the Bohai Sea and Yellow Sea posed higher transport risks, may serve as sources of pollution to the surrounding regions.

Current research status on the distribution and transport of micro(nano)plastics in hyporheic zones and groundwater

Micro(nano)plastics, as an emerging environmental pollutant, are gradually discovered in hyporheic zones and groundwater worldwide. Recent studies have focused on the origin and spatial/temporal distribution of micro(nano)plastics in regional groundwater, together with the influence of their properties and effects of environmental factors on their transport. However, the transport of micro(nano)plastics in the whole hyporheic zone-groundwater system and the behavior of co-existing substances still lack a complete theoretical interpretation. To provide systematic theoretical support for that, this review summarizes the current pollution status of micro(nano)plastics in the hyporheic zone-groundwater system, provides a comprehensive introduction of their sources and fate, and classifies the transport mechanisms into mechanical transport, physicochemical transport and biological processes assisted transport from the perspectives of mechanical stress, physicochemical reactions, and bioturbation, respectively. Ultimately, this review proposes to advance the understanding of the multi-dimensional hydrosphere transport of micro(nano)plastics centered on groundwater, the microorganisms-mediated synergistic transformation and co-transport involving the intertidal circulation. Overall, this review systematically dissects the presence and transport cycles of micro(nano)plastics within the hyporheic zone-groundwater system and proposes prospects for future studies based on the limitations of current studies.

Exploring the molecular mechanisms of herbicide adsorption on microplastics: A quantum chemical approach

The widespread presence of microplastics in the environment has raised significant concerns, particularly regarding their potential interactions with herbicides and the combined pollution effects on ecosystems. In this study, quantum chemical calculations were employed to investigate the interaction mechanisms between polyethylene (PE) and polyvinyl chloride (PVC) microplastics and phenoxyacetic herbicides. The results revealed that PVC exhibits a stronger adsorption capacity compared to PE, and that low ionic strength conditions weaken the interactions between microplastics and herbicides. The energy decomposition analysis indicates that dispersion and electrostatic interactions are the predominant components contributing to the interaction energy, thus positioning the herbicide adsorption sites on microplastics near the minima of van der Waals and electrostatic potentials. The presence of hydrogen bond acceptors in microplastics influences the formation of intramolecular or intermolecular hydrogen bonds with the carboxylic groups of herbicides, resulting in significant changes in vibrational modes and infrared spectral absorption peaks, which offers a potential method for in situ monitoring of herbicide adsorption on microplastics. Additionally, different charge transfer phenomena are observed during the adsorption process, with PVC tending to lose electrons and PE to gain electrons. These insights provide a theoretical foundation for a deeper understanding of the adsorption behavior of phenoxyacetic herbicides on microplastics and hold significant implications for the optimization of environmental remediation strategies.

Key adsorbents and influencing factors in the adsorption of micro- and nanoplastics: A review

Microplastics and nanoplastics (MNPs) are emerging contaminants in drinking water sources that pose serious risks to human health and ecosystems. Several removal strategies, such as adsorption, exist but present challenges for their industrial scalability. This review provides a concise overview of MNP adsorption mechanisms and highlights the limited but critical exploration of column adsorption in the literature, emphasizing its importance for large-scale applications. Special attention is given to carbon-based materials due to their cost-effectiveness, environmental friendliness and sustainability. Other adsorbents (e.g., metal-organic frameworks, clays) are also discussed for their promising performance in realistic water matrixes. To predict and optimize the efficiency of adsorbents, leading simulation models are reviewed. Taken together, this work provides a comprehensive overview of the fundamental factors, such as adsorption mechanisms, adsorbent selection and experimental conditions, to optimize MNP adsorption. By highlighting the underexplored area of column-based processes, it provides valuable information to advance adsorption as a viable industrial-scale solution for MNP contamination.

Revealing the removal behavior of polystyrene nanoplastics and natural organic matter by AlTi-based coagulant from the perspective of functional groups

The interactions of nanoplastics (NPs) with natural organic matter (NOM) are influenced by their surface functional groups. In this study, the effects of representative functional groups on the interactions among polystyrene nanoplastics (PS-COOH and PS-NH2), hydrophilic low molecular weight (LMW) substances (salicylic acid (SA), phthalic acid (PA), and gluconic acid (GA)), and a novel AlTi-based coagulant were investigated. We found that PS-NH2 (83.02 % - 93.38 %) was easier to remove over a wider pH range than PS-COOH (6.94 % - 91.07 %). PS-COOH and PS-NH2 were both able to interact with SA (-OH, -COO-, and benzene ring) through hydrogen bonding, π-π conjugation, and n-π electron donor-acceptor interactions. However, the binding of PS-COOH/PS-NH2 with SA has no effect on the interaction strength between SA and PATC due to the preferential occupation of the coagulant binding sites by SA. The lower SA removal in the PS-COOH@SA system was attributed to its stronger electrostatic repulsion and hydrophilicity. PATC could form carboxylate outer and C-O inner complexes with SA and carboxylate inner complexes with PA. In this study, the analysis of the interaction mechanisms among metal-based coagulants, NPs, and LMW substances lays a theoretical foundation for further research and understanding of coagulation theory.

Changes in population fitness and gene co-expression networks reveal the boosted impact of toxic cyanobacteria on Daphnia magna through microplastic exposure

The concomitant prevalence of toxic cyanobacteria blooms and plastic pollution in aquatic ecosystems is emerging as a pressing global water pollution dilemma. While toxic cyanobacteria and microplastics (MPs) can each independently exert significant impacts on aquatic biota, the magnitude and trajectory of the combined interactions remains rudimentary. In this study, we evaluated how MPs influences cyanobacterial stress on keystone grazer Daphnia, focusing on population, individual, biochemical and toxicogenomic signatures. We found that toxic Microcystis (TM) adversely affected the fitness of Daphnia populations (intrinsic rate of population increase), and these adverse effects were amplified in the presence of MPs. Through detailed observation, it was ascertained that MPs promoted the ingestion of TM, culminating in enhanced microcystin bioaccumulation. Using the Eco-Evo model, we found that there was potential absence of correlation between the MPs toxicity and the effect size of MPs on the TM. Utilizing gene set enrichment analysis (GSEA), we further identified a marked suppression of molecular pathways and entities crucial to individual growth and development in the TM-MPs consortium compared to exposure to TM alone. The present study provides important insights about the influence of MPs on cyanobacteria toxicity and the prediction the risk of harmful algal blooms in aquatic ecosystems.

Exposure to polystyrene nanoplastics induces lysosomal enlargement and lipid droplet accumulation in KGN human ovarian granulosa cells

Given the ubiquitous presence of plastic products in daily life, human exposure to nanoplastics (NPs) is inevitable. Previous studies have suggested that exposure to polystyrene nanoplastics (PSNPs) may contribute to reproductive disorders; however, the underlying mechanism remains elusive. The goal of this study was to investigate the impact of PSNPs on KGN human ovarian granulosa cells. KGN cells were exposed to varying concentrations of PSNPs (0-400 μg/mL) for 48 h; alterations in cell survival and morphology were assessed to elucidate potential toxic effects. PSNPs were shown to enter KGN cells. Exposure to PSNPs did not induce significant changes in cytotoxicity, Calcein intensity, or active mitochondria levels in KGN cells. However, PSNP exposure did induce a dose-dependent increase in cytoplasmic vacuoles and an increase in total lysosome area and in the numbers of lipid droplets in KGN cells. Our findings provide compelling evidence that PSNPs can penetrate cell cytoplasm and induce toxicity, resulting in an elevation in the numbers of lysosomes and lipid droplets. This may represent one mechanism by which PSNPs exert damage on the reproductive system.

Marine micro(nano)plastics toxicology: Knowledge gaps and perspectives

Micro(nano)plastics (MNPs) have emerged as pervasive contaminants widely documented across diverse environmental systems. Concerns regarding their environmental and human health impacts have escalated. Numerous studies have explored various aspects of the environmental toxicology of MNPs, particularly their effects on marine biota. However, significant knowledge gaps persist, hindering the ability to conduct effective environmental risk assessments for these plastic particles. This perspective highlights the critical aspects of MNPs' environmental toxicology that require advanced technological approaches to track and quantitatively reveal their subtle yet profound impacts. These aspects include ecological contexts extending beyond traditional toxicology, MNPs kinetics (uptake, transformation, and accumulation), modeling for simulating these processes under various scenarios, and identification of specific biomarkers associated with MNPs exposure. The establishment of environmental quality criteria for MNPs, if deemed necessary, will depend heavily on a comprehensive understanding of their behavior, toxicity, and ecological consequences. Ultimately, a deeper understanding of MNPs' environmental toxicology is essential for safeguarding both ecological integrity and human health in the face of this growing global challenge.

Measurement and daily consumption of microplastics in drinking water from a Small Island Developing State-Fiji: from freshwater to groundwater sources

The occurrence of microplastics (MPs) in drinking water has emerged as a significant source of this contaminant, posing an increased risk to human health. These MPs are now of extreme concern, especially on the possible harmful effects it may have on human health. This study is the first baseline MPs data in drinking water from Fiji. Raw, treated, tap, rain, ground, and bottled water were investigated for the presence of MPs and the ingestion rate by the different age groups. The analytical procedure was validated by determining recovery rates and analyses of blanks. The detection limit of the MPs was 10 µm, while fibers and particles ≥ 100 µm were analyzed on 100% of the filter area. The abundance of MPs in drinking water was source-dependent. Percentage removal of MPs from water treatment plants was 45-67%, resulting in the presence of 0.10 ± 0.03 to 2.90 ± 0.57 MPs L-1 in tap water. The presence of MPs in bottled, rain, and groundwater was in the range of 0 to 2.20 ± 0.41 MPs L-1. Fiber MPs predominated in all water sources except for bottled water. Main types of polymer identified were polyethylene, polypropylene, and poly(ethylene terephthalate). Estimated daily intake of MPs in tap water by children and adults were 0.0031-0.1813 and 0.0021-0.0829 MPs/kg bw/day, respectively. Information from this work in combination with information from the health sector will help to fully understand microplastic impact on human health and the actions that are required to mitigate it.

Distribution characteristics and transport processes of biodegradable microplastics in the Seto Inland Sea, Japan

Microplastics (MPs) pollution is a prevalent environmental problem that affects ecosystems globally. Despite the growing research on the environmental effects of MPs, a significant research gap remains in understanding the differences of environmental behavior and distribution patterns between biodegradable MPs and traditional MPs. Using a three-dimensional hydrodynamic model and treating MPs as tracers with vertical velocity, this study simulated the transport of positively, neutrally, and negatively buoyant biodegradable MPs from rivers. The results show that positively buoyant MPs have significant seasonal variations and are mainly distributed in the surface layer. Neutrally buoyant MPs are distributed in all water depths, with a high (low) concentration in the eastern (western) Seto Inland Sea (SIS), characterized by winter mixing and summer stratification. Negatively buoyant MPs accumulate in the sediments and exhibit lower concentrations in seawater. Positively and neutrally buoyant MPs mainly outflow from the SIS into the Pacific Ocean, whereas negatively buoyant MPs hardly leave the SIS and are primarily deposited and degraded near river mouths. A settling velocity of -10-6 to -5×10-5 m s-1 (downward) greatly affects the concentration of MPs in seawater. However, large upward and downward velocities outside this range do not result in pronounced changes. Compared with traditional MPs, biodegradable MPs are less environmentally persistent by not accumulating in sediments and keeping a low concentration there, which contributes to the reduction of transport flux of MPs to the Pacific Ocean.

Artificial digestion represents the worst-case scenario for studying nanoplastic fate in gastrointestinal tract

Humans may inevitably be exposed to nanoplastics (NPls) through ingestion. The size of NPls significantly influences their absorption efficiency, so understanding behaviors of NPls during digestion is vital for risk assessment. In this study, fluorescent polystyrene (PS) and melamine-formaldehyde resin (MF) NPls were characterized by different techniques after the in vitro digestion process both with and without a standard food model, or with and without pH adjustment in the absence of the proteins. Results derived from the in vitro method were compared to those using human and porcine digestive fluids. In summary, different types/charges of NPls caused distinct agglomeration states during the digestion procedure, and the pH and protein corona affected the agglomeration state of smaller PS particles more obviously than they did the other tested particles. The presence of a food matrix did not significantly change the particle size, while the protein corona composition was largely altered. Compared to real digestive fluids, size trends observed for NPls were consistent with those in artificial ones, while they were mostly underestimated, which for the first time, proves that the in vitro digestion can be regarded as a conservative model for predicting aggregation of NPls in gastrointestinal tract.

The wheel of time: The environmental dance of aged micro- and nanoplastics and their biological resonance

The aging of micro- and nanoplastics (MNPs) significantly affects their environmental behavior and ecological impacts in both aquatic and terrestrial ecosystems. This review explored the known effects of aging on MNPs and identified several key perspectives. Firstly, aging can alter the environmental fate and transport of MNPs due to changes in their surface properties. This alteration accelerates their accumulation in specific habitats like oceans and soils, resulting in increased bioaccumulation by organisms. In addition, aged MNPs interact differently with living organisms than their pristine counterparts by influencing the attachment of biofilms and other microorganisms in aquatic ecosystems. Moreover, the aging processes of MNPs exhibit adverse effects on aquatic and terrestrial organisms via increasing the bioavailability and potential toxicity of MNPs as degradation products are released. Last but not least, the biodegradation potential of MNPs can be altered by the aging process, thus affecting their degradation rates and pathways in the environment. However, there are still knowledge gaps regarding the natural aging behaviors of MNPs, such as the aging mechanisms of different types of plastic, the influence of environmental factors, the release of pollutants, and even the effects of aging on their transformation in different ecosystems. Therefore, a great contribution can be made to sustainable plastic use and environmental preservation by studying the natural aging of common MNPs and their subsequent biological effects.

Enhanced uptake of perfluorooctanoic acid by polystyrene nanoparticles in Pacific oyster (Magallana gigas)

The effects of plastic pollution on marine organisms is of growing concern. The hydrophobic surface of plastics adsorbs organic contaminants and can alter the rate of chemical uptake in fishes. Per-fluorinated organic chemicals such as Perfluorooctanoic acid (PFOA) are highly hydrophobic toxic chemicals that adsorb to hydrophobic surfaces. We hypothesized that the presence of nano-sized plastic particles adsorbs PFOA and alter both the physical-chemical properties of the plastics and also enhance PFOA uptake into organisms. Using radiolabelled 14C-PFOA, we measured direct unidirectional uptake of PFOA in juvenile Pacific Oysters (Magallana gigas) at different (0.025, 0.50, and 0.100 mg/L) concentrations, for different exposure periods (1, 2, 4, and 6 h) and investigated whether varying concentrations (0.1, 0.5, 1 mg/L) of either 500 nm or 20 nm polystyrene nanoparticles (PS-NPs) differentially altered the uptake rate of PFOA. Our results demonstrate that PFOA adsorbs to the surface of PS-NPs, altering PS-NP behaviour in solution and significantly increases the rate of uptake of PFOA in exposed Pacific oysters. PFOA uptake at 0.1 mg/L was increased 2.3-fold in the presence of 1 mg/L 500 nm PS-NP and 3.2-fold in the presence of 1 mg/L 20 nm PS-NP. In a separate study to examine if PS NPs potentiate the biochemical response to PFOA, both 500 and 20 nm PS-NP at 100 mg/L increased the 1 mg/L PFOA-induced oxidative stress by 2.5-fold and 3-fold respectively. These findings demonstrate that nanoplastics as co-contaminants in marine systems are able to adsorb PFOA and significantly potentiate its uptake and toxicity.

Efficient and stable extraction of nano-sized plastic particles enabled by bio-inspired magnetic "robots" in water

In this research, a rationally-designed strategy was employed to address the crucial issue of removing nano-plastics (NPs) from aquatic environments, which was based on fabricating sea urchin-like structures of Fe3O4 magnetic robots (MagRobots). Through imitating the sea urchin's telescopic tube foot movement and predation mechanism, the unique structures of the MagRobots were designed to adapt to the size and surface interactions of NPs, leading to a high efficiency of NPs removal (99%), as evidenced by the superior performance of 594.3 mg/g for the removal of polystyrene (PS) nanoparticles from water, with 3300% increase over magnetic Fe3O4 without structural design. The adsorption process was further analyzed using density functional theory (DFT) models and adsorption experiments, indicating that it was driven by electrostatic interactions. MagRobots maintained an adsorption capacity of up to 328 mg/g over four cyclic experiments and demonstrated high-capacity adsorption (close to 400 mg/g) in natural water bodies. The results of the simulations were supported by experiments that verified the excellent adsorption performance, regeneration effect, and environmental stability of the MagRobots under both simulated and real-world water conditions. This ingenious structural strategy provided valuable perspectives for the development of efficient magnetic porous materials for wastewater treatment, which would have potential applications for the treatment of NPs in real aquatic ecosystems. The unique sea urchin-like structures of the MagRobots could offer an innovative approach to tackle the challenge of NPs removal.

Interactions between nanoplastics and Tetrahymena thermophila: Low toxicity vs. potential biodegradation

Nanoplastics (NPs) are prevalent throughout the environment and have raised growing environmental concerns. Although numerous studies have examined the toxicological aspects of NPs, few have investigated their environmental fate and behavior when affected by organisms other than bacteria or fungi. Planktonic ciliates are essential components of aquatic ecosystems and play important roles in decomposing organic matter and transferring energy from the microbial food web to higher trophic levels. To investigate the interplay between NPs and the ciliate Tetrahymena thermophila, we executed a sequence of feeding experiments utilizing 50 nm polystyrene nanoplastics (PS-NPs). In the presence of sufficient nutrition, exposure to PS-NPs (even at concentrations up to 500 mg/L) did not significantly inhibit growth in Tetrahymena thermophila, indicating only a mild toxic effect of PS-NPs. When ingested by T. thermophila, the PS-NPs are repackaged into aggregates with lysosomal components in the food vacuole and finally expelled as compacted "fecal pellets". This process modifies the physical attributes of PS-NPs, including their hydrophilicity, aggregability, and buoyancy, influencing their transportation, retention, deposition dynamics, and ultimately their bioavailability within the environment. A total of 73 proteins were identified from the fecal pellets, containing various hydrolases. Gel permeation chromatography (GPC), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA) were used to identify changes in molecular weights, functional groups, and thermal stabilities of PS-NP residues in fecal pellets. The results verified the degradation of PS-NPs during the passage through the T. thermophila cell.

Bacillus subtilis, a promising bacterial candidate for trapping nanoplastics during water treatment

As a probiotic, Bacillus subtilis (B. subtilis) has a wide range of application values. In this study, the trap by B. subtilis and the effect of NPs on its growth physiology were studied. Confocal laser scanning microscopy (LCSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that PS-NPs were trapped by B. subtilis when they were exposed to PS-NPs. At this point, most of the PS-NPs are clustered around B. subtilis. Flow cytometry showed that at 10 mg/L, 73.7 % of PS-NPs' environmental state changed. The complexity of 9.73 %, 23.77 %, 43.27 %, and 65.13 % of B. subtilis increased at PS-NP concentrations of 10, 20, 50, and 200 mg/L, respectively. The increase in overall EPS secretion ranged from 0.51 ∼ 7.13 μg/mL after adding different concentrations of PS-NPs. The effect of different concentrations of PS-NPs on NAR activity ranged from -11.38 ∼ 16.2 %, on NIR activity from -17.90 ∼ 7.22 %, on NOR activity from -15.10 ∼ 7.69 % and on NO2R activity from -14.01 ∼ 17.03 %. These results indicated that B. subtilis can process nitrogen compounds in water while capturing NPs in the environment. They have the potential to be candidate bacteria in the water treatment process, and specific applications are needed to research further.

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.

Using a citizen science approach to assess nanoplastics pollution in remote high-altitude glaciers

Nanoplastics are suspected to pollute every environment on Earth, including very remote areas reached via atmospheric transport. We approached the challenge of measuring environmental nanoplastics by combining high-sensitivity TD-PTR-MS (thermal desorption-proton transfer reaction-mass spectrometry) with trained mountaineers sampling high-altitude glaciers ("citizen science"). Particles < 1 μm were analysed for common polymers (polyethylene, polyethylene terephthalate, polypropylene, polyvinyl chloride, polystyrene and tire wear particles), revealing nanoplastic concentrations ranging 2-80 ng mL- 1 at five of 14 sites. The dominant polymer types found in this study were tire wear, polystyrene and polyethylene particles (41%, 28% and 12%, respectively). Lagrangian dispersion modelling was used to reconstruct possible sources of micro- and nanoplastic emissions for those observations, which appear to lie largely to the west of the Alps. France, Spain and Switzerland have the highest contributions to the modelled emissions. The citizen science approach was found to be feasible providing strict quality control measures are in place, and is an effective way to be able to collect data from remote and inaccessible regions across the world.

Removal of microplastics by algal biomass from aqueous solutions: performance, optimization, and modeling

Microplastics (MPs) are emerging pollutants that pose significant risks to ecosystems due to their inherent toxicity, capacity to accumulate various pollutants, and potential for synergistic impacts. Given these concerns, the focus of this research is on the critical need for effective MPs removal from aquatic environments. Using BBD method, this study aimed to identify the key parameters affecting the removal of MPs by algal biomass from aqueous solutions. The investigation specifically analyzed the effects of varying initial PS concentrations (100 to 900 mg/L), pH values (4 to 10), reaction durations (20 to 40 min), and C. vulgaris dosages (50 to 400 mg/L). Data analysis indicated that QM best described the experimental findings, leading to the identification of optimal conditions for PS removal: a pH of 7.5, a reaction time of 31.90 min, a C. vulgaris dosage of 274.05 mg/L, and a PS level of 789.37 mg/L. Under these conditions, the study achieved a maximum removal efficiency of 73.01% for PS. These outcomes demonstrate the significant potential of C. vulgaris in efficiently removing PS from water. Furthermore, using algae as a green, eco-friendly alternative to conventional chemical coagulants offers a practical and sustainable approach to addressing MPs pollution in our water systems.

Microplastics induced ileum damage: Morphological and immunohistochemical study

Microplastics (MPs) are small pieces of plastic that are widely distributed in the environment and accumulate within living organisms, so they are the most common types of pollutants at the present time. One of the most widespread types of MP in the environment is polyethylene (PE) MPs. There have been many published studies on the effect of PE MPs combined with other pollutants or chemicals such as benzoanthracene, emamectin benzoate, heavy metals and 4-nonylphenol, on some marine, amphibian, and mouse models. However, research has rarely been conducted on how single-use PE MPs affect the ileum of mammals. The current study is focused on the impact of PE MP exposure with different concentration (6, 60, 600 μg/mL PE/MPs) for 15 days, followed by 15 days of recovery on small intestine(ileum) of C57BL/6 murine model with precision and detail at the cell level by using different technique (histology, histochemistry, immunohistochemistry, and transmission electron microscope). Results demonstrated that the intestinal tissue exhibited nuclear pyknosis, villus deformation, shortness of villi, degeneration of lamina propria, hyperplasia of goblet cells, increase of goblet cells secretion, Alcian blue and Periodic acid-Schiff stain positivity of intact goblet cells, highly significance of P53 immunoreaction expression specially in high concentrations (600 μg/day of PE/MPs) and Ki-67 immunoreaction expression. RESEARCH HIGHLIGHTS: Different doses of microplastics (MPs) induced sever morphological alternations and clinical observations. MPs were deposits in cells and were observed in ultrastructure study. Recovery period able to ameliorate to the most extent the alternations caused by MPs administration.

Microplastic pollution: A global perspective in surface waters, microbial degradation, and corresponding mechanism

Plastics are incredibly useful materials that have many benefits for both society and individual daily lives. However, the extensive utilization of plastic and plastic-derived products has led to plastic pollution in various environmental compartments across the world at alarming levels. Due to different biogeochemical processes, this plastic waste is broken down into tiny, omnipresent, and long-lasting fragments known as microplastics (<5 mm), which are causing great concern among scientists. Microplastics tend to bioaccumulate, contain toxic chemicals, and have other pollutants and pathogens adsorbed on their surface, thus having adverse effects on organisms. Globally dispersed, microplastics can now be found in almost every environmental niche. Therefore, the purpose of this paper is to give an overview of the research that has been done on this topic, summarize the evidence of microplastic pollution in surface waters, and discuss the analytical summary of recent findings on the microbial degradation of microplastics and effects of various parameters on its degradation as well as the potential degradation mechanism of microplastics. A summary of the most recent and relevant literature is provided on microplastic pollution and microorganisms that can break down various microplastics are classified according to their types including bacteria, fungi, and algae. The environmental factors influencing microplastic degradation and the associated degradation effects are therefore generalized. Additionally, a brief discussion of the mechanism underlying the microbial-mediated degradation of microplastics is provided. This review serves as a reference for upcoming research looking into efficient ways to reduce microplastic pollution.

Combined toxic effects of polystyrene microplastic and benzophenone-4 on the bioaccumulation, feeding, growth, and reproduction of Daphniamagna

The potential toxicity of microplastics (MPs) and UV filter Benzophenone-4 (BP4) to aquatic organisms has caused widespread concern among the public. However, the combined effects of MPs and BP4 on aquatic organisms are not well understood. This study sought to examine the combined impacts of 10 μg/L BP4, 1 mg/L Polystyrene (PS, 10 μm), and a mixture of both on the feeding, behavior, growth, and reproduction of Daphnia magna (D. magna) over a period of 21 days. The results showed that the combined exposure led to a reciprocal facilitation of bioaccumulation, along with a decrease in the second antenna beats frequency in D. magna. While the co-exposure did not change the body size or growth rate of D. magna, it did affect their feeding efficiency, leading to a decrease in Chlorella ingestion within a 24-h period. Furthermore, there was a high occurrence of malformations in two generations of D. magna exposed to BP4 and PS. The combined exposure also negatively affected reproductive parameters, such as the cumulative number of neonates and the days of first brood, suggesting a decline in overall reproductive success possibly due to feeding inhibition, with available energy potentially being redistributed between reproduction and growth in the daphnids. Co-exposure to BP4 and PS also led to elevated levels of Reactive Oxygen Species (ROS), Malonydialdehyde (MDA), and Glutathione (GSH) levels, as well as mRNA levels related to reproduction, growth, and detoxification in D. magna. Overall, this study delved into the consequences of BP4 and PS on bioaccumulation, feeding, behavior, growth, and reproduction, demonstrating that simultaneous exposure to BP4 and PS could pose a synergistic ecological hazard, potentially threatening aquatic organisms. These findings are critical and should be taken into account for accurate environmental risk assessments.

Comparative analysis of the microbial plastisphere at three sites along the Sarno river (Italy)

This study investigated microplastics (MP) and their associated microbial plastisphere in the Sarno river (Italy), its estuary and in the nearby coastal area in January 2020. Scanning Electron Microscopy (SEM), High Throughput Sequencing (HTS) and Fourier-Transformed Infrared Spectroscopy (FTIR) were used to characterize the collected MPs and their associated microbes. The three stations sampled differed substantially for MP concentrations and microbial communities, with the estuarine station showing very high MP concentrations (2048.6 MP m-3), highlighting the threat represented by the river for the coastal marine area and its ecosystem. The prokaryotic plastisphere showed differences between the three stations sampled, in terms of community composition, with only 75 Amplicon Sequence Variants (ASV) in common. The Comamonadaceae was the most abundant family in MP-attached and freshwater communities, and this lifestyle seems to be pivotal in the colonization of new habitats while flowing towards the sea. The results highlight the importance of the plastisphere in colonization of new habitats and support the need of correct management and risk mitigation efforts.

The combined effects of polystyrene nanoplastics and dissolved organic matter on the environmental bioavailability of carbamazepine

The bioavailability of active pharmaceutical ingredients (APIs) plays a crucial role in determining the toxicity and risk of contaminants in the environment. However, the bioavailability of APIs in complex environmental matrices is still unclear. In this study, the combined effects of polystyrene nanoplastics (PS NPs) with various particle sizes (50, 100, and 1000 nm) and fulvic acid (FA) on the bioavailability of carbamazepine (CBZ) were investigated via negligible depletion solid-phase microextraction (nd-SPME) and Daphnia magna (D. magna) accumulation. The uptake kinetic study revealed that both PS NPs and FA reduced the elimination rate (k2) in most cases. The availability of CBZ to nd-SPME was determined by the hydrodynamic particle size of PS NPs, whereas the bioavailability to D. magna depended on the intrinsic particle size. The CBZ bioavailability was greater in co-exposed matrices due to the attenuated sorption of PS NPs to CBZ by FA modification. Notably, co-exposure of PS NPs and FA resulted in a higher bioaccumulation factor (BAF) of CBZ, probably due to the desorption and reabsorption of particle-associated CBZ. This study demonstrated that both PS NP particle size and FA binding affect the bioavailability of CBZ, and nd-SPME can mimic only the bioaccumulation of CBZ via diffusion.

UV-B radiation aging changed the environmental behavior of polystyrene micro-/nanoplastics-adsorption kinetics of BDE-47, plankton toxicities and joint toxicities with BDE-47

UV-B radiation acts as an important environmental factor for aging micro-/nanoplastics (MNPs) in the marine environments, while the effect of aged MNPs on plankton is lacking specific research. Referencing to the UV-B radiation intensity in natural environments (2.29 W·m-2), we chose the floating polystyrene (PS) MNPs (50 nm, 1 µm) as the research target in this study. The results indicated that UV-B radiation aging for 30 days led to a rougher surface, increased SBET, increased hydrophobicity, and decreased negative charges of PS MNPs. Correspondingly, aged MNPs increased their adsorption abilities for 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), especially for the initial stage. After UV-B radiation aging processes, the individual toxicities of the two sized MNPs on Thalassiosira pseudonana and Brachionus plicatilis both increased, while their joint toxicities with BDE-47 decreased on T. pseudonana but increased on B. plicatilis. The changes in toxicity were more pronounced in 1 µm PS MNPs under air-aged conditions. This study provided the data basis for evaluating the changes of MNPs environmental behaviors under UV-B radiation in the marine environments, with important ecological significance.

Preparation of fragmented polyethylene nanoplastics using a focused ultrasonic system and assessment of their cytotoxic effects on human cells

With the growing prevalence of plastic use, the environmental release of plastic waste is escalating, and fragmented nanoscale plastic particles are emerging as significant environmental threats. This study aimed to evaluate the cytotoxic effects of fragmented polyethylene nanoplastics (PE NPs) manufactured using a focused ultrasonic system. The ultrasonic irradiation process generated fragmented PE NPs with a geometric mean diameter of 85.14 ± 5.37 nm and a size range of 25-350 nm. To assess cytotoxicity, we conducted a series of tests on various human cell lines, including stomach, blood, colon, lung, skin, liver, and brain-derived cells. The testing involved MTS-based cell viability assays to evaluate direct impacts on cell viability, lactate dehydrogenase (LDH) leakage assays to measure membrane damage, and ELISA to quantify TNF-α release as an indicator of inflammation. Although PE-NPs did not immediately induce apoptosis, significant LDH leakage and elevated TNF-α levels were observed across all cell lines, indicating membrane damage and inflammatory responses. Additionally, flow cytometry and TEM analyses revealed the intracellular accumulation of PE-NPs, further supporting their cytotoxic potential. These results demonstrate that fragmented PE-NPs can disrupt cellular membranes and induce inflammatory responses through accumulation within cells. The findings suggest that these NPs pose potential hazards to cell viability and underscore the need for further research into their environmental and health impacts.

Co-exposure to microplastics and soil pollutants significantly exacerbates toxicity to crops: Insights from a global meta and machine-learning analysis

Environmental contamination of microplastics (MPs) is ubiquitous worldwide, and co-contamination of arable soils with MPs and other pollutants is of increasing concern, and may lead to unexpected consequences on crop production. However, the overall implications of this combined effect, whether beneficial or detrimental, remain a subject of current debate. Here, we conducted a global meta and machine-learning analysis to evaluate the effects of co-exposure to MPs and other pollutants on crops, utilizing 3346 biological endpoints derived from 68 different studies. Overall, compared with control groups that only exposure to conventional soil contaminants, co-exposure significantly exacerbated toxicity to crops, particularly with MPs intensifying adverse effects on crop morphology, oxidative damage, and photosynthetic efficiency. Interestingly, our analysis demonstrated a significant reduction in the accumulation of pollutants in the crop due to the presence of MPs. In addition, the results revealed that potential adverse effects were primarily associated with crop species, MPs mass concentration, and exposure duration. Our study reaffirms the substantial consequences of MPs as emerging pollutants on crops within the context of integrated pollution, providing novel insights into improving sustainability in agro-ecosystems.

Trophic transfer effects of PS nanoplastics and field-derived nanoplastics in the freshwater clam Corbicula fluminea

Plastic pollution is of global concern. Many studies investigated the effect of micro and nanoplatics towards aquatic organisms. However, relatively few studies were assessed on freshwater organisms. Another aspect of this pollution is the impact of trophic transfer on plastic distribution and on food chain in order to evaluate its potential risk towards environmental and human health. In this context, the objective of this study was to assess the ecotoxicological impacts of different types of nanoplastics (NPs) on freshwater organisms exposed through trophic transfer. Freshwater microalgae Scenedesmus subspicatus were contaminated for 48 h with realistic concentrations of NPs (0.008, 10 and 100 µg/L). Two types of NPs were tested: commercial PS NPs and NPs generated from macro-sized plastics collected in the field (ENV NPs). Freshwater Corbicula fluminea bivalves were then fed with the contaminated algae every 48 h for 21 days. Results showed that trophic exposure led to the induction of oxidative stress (CAT activity). Overall, NPs trophic exposure caused downregulations of genes implicated in many cellular processes (immunity, oxidative stress, neurotoxicity, endocytosis, apoptosis). This present study allowed to demonstrate the relevance of investigating the trophic transfer effects of NPs on a freshwater trophic chain. Further studies should focus more on larger levels of the food chain.

New molecular mechanism of nanoplastics affecting cadmium protein toxicity: Conformational response and differential binding of human serum albumin

The significant health risks of nanoplastics (NPs) and cadmium (Cd) are currently attracting a great deal of attention and research. At present, the effects and mechanisms of NPs and Cd on human serum albumin (HSA), a key functional protein in the organism on transportation, remain unknown. Here, the differences in the effects and mechanisms of action of Cd alone and composite systems (NPsCd) were explored by enzyme activity assay, multi-spectroscopy analysis and molecular docking. The results showed that HSA activity was inhibited and decreased to 80 % and 69.55 % (Cd = 30 mg/L) by Cd alone and NPs-Cd exposure, respectively. Exposure to Cd induced backbone disruption and protein defolding of HSA, and secondary structure disruption was manifested by the reduction of α-helix. Cd exposure also induces fluorescence sensitization of HSA. Notably, the addition of NPs further exacerbated the effects associated with Cd exposure, which was consistent with the changes in HSA activity. Thus, the above conformational changes may be responsible for inducing the loss of enzyme activity. Moreover, it was determined by RLS spectroscopy that NPs-Cd bound to HSA in the form of protein crowns. Molecular docking has further shown that Cd binds to the surface of Sudlow site II of HSA, suggesting that Cd impairs the function of HSA by affecting the protein structure. More importantly, the addition of NPs further exacerbated the disruption of the protein structure by the adherent binding of HSA on the surface of the plastic particles, which induced a greater change in the enzyme activity. This study provides useful perspectives for investigating the impact of composite pollution on HSA of human functional proteins.

2,7-Phloroglucinol-6,6'-bieckol from Ecklonia cava ameliorates nanoplastics-induced premature endothelial senescence and dysfunction

Nanoplastics (NPs), plastic particles ranging from 1 to 100 nm are ubiquitous environmental pollutants infiltrating ecosystems. Their small size and widespread use in various products raise concerns for human health, particularly their association with cardiovascular diseases (CVD). NPs can enter the human body through multiple routes, causing oxidative stress, and leading to the senescence and dysfunction of endothelial cells (ECs). Although there are potential natural compounds for treating CVD, there is limited research on preventing CVD induced by NPs. This study investigates the efficacy of Ecklonia cava extract (ECE) in preventing NPs-induced premature vascular senescence and dysfunction. Exposure of porcine coronary arteries (PCAs) and porcine coronary ECs to NPs, either alone or in combination with ECE, demonstrated that ECE mitigates senescence-associated β-galactosidase (SA-β-gal) activity induced by NPs, thus preventing premature endothelial senescence. ECE also improved NPs-induced vascular dysfunction. The identified active ingredient in Ecklonia cava, 2,7'-Phloroglucinol-6,6'-bieckol (PHB), a phlorotannin, proved to be pivotal in these protective effects. PHB treatment ameliorated SA-β-gal activity, reduced oxidative stress, restored cell proliferation, and decreased the expression of cell cycle regulatory proteins such as p53, p21, p16, and angiotensin type 1 receptor (AT1), well known triggers for EC senescence. Moreover, PHB also improved NPs-induced vascular dysfunction by upregulating endothelial nitric oxide synthase (eNOS) expression and restoring endothelium-dependent vasorelaxation. In conclusion, Ecklonia cava and its active ingredient, PHB, exhibit potential as therapeutic agents against NPs-induced premature EC senescence and dysfunction, indicating a protective effect against environmental pollutants-induced CVDs associated with vascular dysfunction.

Adsorption behavior and quantum chemical analysis of surface functionalized polystyrene nano-plastics on gatifloxacin

In this paper, the adsorption of gatifloxacin (GAT) by three types of polystyrene nano-plastics (PSNPs), including 400 nm polystyrene (PS), amino-modified PS (PS-NH2), and carboxyl-modified PS (PS-COOH) was studied and the adsorption mechanism were assessed. Experimental findings revealed that the equilibrium adsorption capacity of PSNPs to GAT followed the order PS-NH2 > PS-COOH > PS. The adsorption was regulated by both physical and chemical mechanisms, with intra-particle and external diffusion jointly controlling the adsorption rate. The adsorption process was heterogeneous, spontaneous, and entropy-driven. Sodium chloride (NaCl), alginic acid, copper ions (Cu2+), and zinc ions (Zn2+) inhibited adsorption, with Cu2+ and Zn2+ having the strongest effect on PS-NH2. Theoretical computations indicated that π-π and electrostatic interactions dominated PS adsorption of GAT, while PS-COOH and PS-NH2 adsorbed GAT through electrostatic interactions, hydrogen bonds, and van der Waals (vdW) forces. The surface electrostatic potential of PS-COOH and PS-NH2 was considerably higher than that of PS, with the maximum vdW penetration distance of GAT-PS-NH2 being 1.20 Å. This study's findings provide a theoretical foundation for the migration and synergistic removal of antibiotics, micro-plastics (MPs), and nano-plastics (NPs).

A strategy for quantifying microplastic particles in membrane filtration processes using flow cytometry

Microplastic (MP) pollution is ubiquitous in the aquatic environment, with significant quantities of MPs originating from municipal wastewater treatment plants. Efforts to evaluate and implement MP removal processes are underway, with membrane technologies often recommended as an "ideal" solution. A key challenge in evaluating these technologies involves efficiently quantifying MP concentrations in samples. Here, flow cytometry (FC) is demonstrated as an effective technique to obtain concentration measurements of plastic microbeads (MBs; 1-5 μm) suspended in water with/without added humic acid. Regardless of solution conditions, MB concentrations were easily quantified via FC. Subsequently, two microfiltration membranes were challenged to these suspensions. As measured via FC, the 0.45 μm membrane demonstrated effective MB rejection (>99%) whereas the 5 μm membrane exhibited a broad range of rejections (40% to >95%) depending on solution conditions and filtration time. Finally, a model was formulated utilizing FC forward light scattering intensity measurements to estimate MB sizes in samples. Using the model, a 33% reduction in median MB size, on average, was noted across the 5 μm membrane when filtering MBs suspended in humic acid solution, affirming a preferential permeation of smaller particles. Overall, this study advances MP quantification techniques towards validating removal processes.

How much do we know about the microplastic distribution in the Mediterranean Sea: A comprehensive review

The Mediterranean Sea is one of the most heavily polluted regions. Here we comprehensively review the current state of microplastic pollution in the Mediterranean Sea and the Black Sea. A total of 284 studies published between 2012 and 2023 were analyzed, revealing a continuous increase in research efforts. Our review encompassed microplastic monitoring studies across five environmental matrices: the sea surface, water column, intertidal sediment, bottom sediment, and biota, with a predominant focus observed in biota-related studies with fish, molluscs, crustaceans, and echinoderms being the primary focus. The study found that species such as Mullus barbatus, Mytilus galloprovincialis, Nephrops norvegicus, and Holothuria tubulosa are frequently studied species. The review also emphasizes the lack of standardized methodologies across studies, which hampers the comparability of results and the synthesis of data. The findings of this study provide a critical evaluation of the current research landscape and identify significant knowledge gaps, particularly in the underrepresented southern Mediterranean and Black Sea regions, calling for more balanced research efforts and methodological consistency in future studies.

Microplastic ingestion induces energy loss on the copepod Tigriopus koreanus

In marine environments, exposure to microplastics threaten various organisms. A large portion of MPs may be bioavailable to copepods, and ingesting MPs has been reported to induce various adverse effects, including increased mortality, developmental retardation, and decreased reproduction. Adverse effects of MPs on these important processes of copepods may be induced by the obstructive effects of the ingested MPs on energy acquisition. However, few studies have explored the biological effects of MPs on copepods in terms of energy budgets. Therefore, we analyzed ATP (adenosine triphosphate) levels, enzyme activities, swimming distances, and excretion rates in marine copepods (Tigriopus koreanus) that have ingested polystyrene microplastics. Our results indicate that the ingestion of MPs may prevent adequate acquisition of nourishment and lead the copepods into a vicious circle in the respect to energetic burden. Our study provides biochemical evidence for a reduction in the energy budget of copepods due to MPs ingestion. Further, this study increases our understanding of the risks of microplastics, by providing advanced evidences of their effects on marine primary consumer.

Dose-dependent effects of polystyrene nanoplastics on growth, photosynthesis, and astaxanthin synthesis in Haematococcus pluvialis

Microalgae play an important role in aquatic ecosystems, but the widespread presence of micro- and nano-plastics (MNPs) poses significant threats to them. Haematococcus pluvialis is well-known for its ability to produce the antioxidant astaxanthin when it experiences stress from environmental conditions. Here we examined the effects of polystyrene nanoplastics (PS-NPs) at concentrations of 0.1, 1, and 10 mg/L on H. pluvialis over an 18-day period. Our results show that PS-NPs caused a significant, dose-dependent inhibition of H. pluvialis growth and a reduction in photosynthesis. Furthermore, PS-NPs severely damaged the morphology of H. pluvialis, leading to cell shrinkage, collapse, content release, and aggregation. Additionally, PS-NPs induced a dose-dependent increase in soluble protein content and a decrease in the production of extracellular polymeric substances. These findings indicate that PS-NPs has the potential to adversely affect both the physiology and morphology of H. pluvialis. An increase in reactive oxygen species and antioxidant enzyme activities was also observed, suggesting an oxidative stress response to PS-NPs exposure. Notably, the synthesis of astaxanthin, which is crucial for H. pluvialis's survival under stress, was significantly inhibited in a dose-dependent manner under strong light conditions, along with the down-regulation of genes involved in the astaxanthin biosynthesis pathway. This suggests that PS-NPs exposure reduces H. pluvialis's ability to survive under adverse conditions. This study enhances our understanding of the toxic effects of PS-NPs on microalgae and underscores the urgent need for measures to mitigate MNP pollution to protect aquatic ecosystems.

Enhanced flotation removal of polystyrene nanoplastics by chitosan modification: Performance and mechanism

Nanoplastics are difficult to remove from water using conventional flotation processes due to their stability and resistance to biodegradation. Here, polystyrene nanoplastics (PSNPs) were selected as the object of study. In addition, chitosan (CTS), an environmentally friendly natural cationic polymer, was selected to modify the air flotation process to improve the separation of PSNPs using air flotation. Adding chitosan effectively enhanced the removal of PSNPs using air flotation from 3.1 % to 96.7 %. The residual concentration decreased from 9.69 mg/L to 0.33 mg/L. Removal of PSNPs by CTS-modified air flotation was maintained at 92.8 % even when the air flotation time was significantly shortened. The zeta potential alterations demonstrated robust electrostatic attraction within the CTS-modified air flotation process. The contact angle measurements indicated that incorporating CTS could enhance the hydrophobic interaction between bubbles and PSNPs. PSNPs particles around 100 nm agglomerated to form floating flocs with a particle size of more than 4500 nm. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) images confirmed the presence of tight adhesion between PSNPs and CTS, indicating the presence of bridging adsorption during the process. The major PSNPs removal mechanisms included electrostatic attraction, enhancement of hydrophobicity, and bridging adsorption. Increasing the aeration volume could improve the removal rate, but this improvement was finite. Weakly acidic and low ionic strength conditions favored PSNPs removal. The CTS-modified air flotation process showed great potential for PSNPs removal from real water bodies.

Controlled Sol-Gel Transitions of Metal-Organic Membrane-Enveloped Cellulose Nanofibrils via Metal Coordination in Aqueous Media

We report a metal coordination-driven sol-gel transition system where cellulose nanofibrils are enveloped by a rationally designed metal-organic membrane (MOM) in an aqueous medium. Specifically, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (TOBC) is encapsulated within an MOM comprising Zn2+ and the chelator phytic acid (PA), denoted TOBCMOM. Using the DLVO theory, we elucidate how tuning the metal ion valence in TOBCMOM modulates the sol-gel transition by controlling interfibrillar attractive forces. Notably, TOBCMOM fluids exhibit relaxation times consistent with the Kohlrausch-Williams-Watts (KWW) function. Significantly, we demonstrate reversible, sustainable sol-gel transitions in TOBCMOM under stepwise mechanical strain. This facile approach enables rheological tailoring of aqueous media, promising for the development of advanced stimuli-responsive smart fluids for applications in cosmetics, food science, and pharmaceutical formulations.

Seasonal variability of microplastic contamination in marine fishes of the state of Gujarat, India

Seasonal variation in microplastics abundance, occurrence, and distribution in pelagic and demersal fishes was observed in this study during December 2021 to November 2022. One hundred percent presence of microplastic in inedible (gut and gills) tissue, while 82% and 54% in edible tissue (muscle) of pelagic and demersal fishes respectively were seen. Post-monsoon period showed high prevalence of microplastics followed by monsoon and the least during pre-monsoon in both pelagic and demersal fishes. In pelagic fishes, the edible tissue had microplastics abundance of 1.56 to 13.34 numbers per 10 g of tissue whereas inedible tissue had 3.36 to 16.67 numbers per 10 g of tissue. In demersal fishes, the edible tissue had microplastics abundance of 1.04 to 5.26 numbers per 10 g of tissue while it was 2.67 to 8.34 numbers per 10 g of inedible tissue. There was significant variation in abundance of microplastic in edible and inedible tissue of all the fishes (Mann-Whitney test, p < 0.05). The most dominant microplastics size was 0.005-0.05 mm followed by 0.05-0.5 mm and the least of greater than 0.5 mm in pelagic and demersal fishes respectively. Taking microplastic shape into consideration, the most dominant was fiber followed by fragment and the film in inedible tissue of all the fishes. The edible tissue of all the fishes had only fiber in them (100% occurrence). The dominance of blue color microplastics was observed followed by red, green, yellow, and orange at least in edible as well as inedible tissues of the fishes. More than 99% microplastics polymer observed in this study include polyethylene (PE), polypropylene (PP), and polystyrene (PS); only less than 1% was unidentified. This is the first study done on seasonal variation of microplastic in the marine fish population of Gujarat waters, Northeast Arabian Sea. The study highlights the nature of micro-pollutant in marine environments, emphasizing the need for comprehensive monitoring and management strategies.

Sorption of PFOS onto polystyrene microplastics potentiates synergistic toxic effects during zebrafish embryogenesis and neurodevelopment

Microplastics (MPs) have become an emerging anthropogenic pollutant, and their ability to sorb contaminants potentially enhances the threats to the ecosystem. Only a few studies are available to understand the combined effects of microplastics and other pollutants. The present study investigated the sorption of perfluorooctane sulfonic acid (PFOS) onto polystyrene microplastics (PS-MPs) at varying concentrations, using molecular dynamics simulation (MDS) to preliminarily explore the adsorption behavior. The MDS results revealed negative interaction energies between PFOS and PS-MPs, underscoring PS-MPs' role as a potential adsorbent for PFOS in an aqueous solution. Thereafter, zebrafish embryos were employed to explore the toxic effects of combined exposure to PS-MPs and PFOS. Fluorescence and Scanning Electron Microscopy (SEM) suggested PS-MP accumulation individually and in combination with PFOS on the embryonic chorion membrane. As a result, the exposed group showed increased inner pore size of the chorionic membrane and accelerated heartbeat, indicating hypoxic conditions and hindered gaseous exchange. PS-MPs aggravated the toxicity of PFOS during larval development manifested by delayed hatching rate, increased mortality, and malformation rate. Additionally, increased ROS accumulation and altered antioxidant enzymatic status were observed in all the exposed groups suggesting perturbation of the redox state. Additionally, co-exposure of zebrafish larvae to PS-MPs and PFOS resulted in an abrupt behavioral response, which decreased AChE activity and altered neurotransmitter levels. Taken together, our results emphasize that PS-MPs can act as a potential vector for PFOS, exerting synergistic toxic effects in the aquatic environment, and hence their health risks cannot be ignored.

Review on personal protective equipment: Emerging concerns in micro(nano)plastic pollution and strategies for addressing environmental challenges

The COVID-19 pandemic was caused by the SARS-CoV-2 virus, marking one of the most catastrophic global health crises of the 21st century. Throughout this period, widespread use and improper disposal of personal protective equipment (PPE) emerged as a pressing environmental issue, significantly impacting various life forms. During the COVID-19 pandemic, there was a high rate of PEP disposal. An alarming 1.6 × 106 tons of plastic waste each day has been generated since the onset of the outbreak, predominantly from the inadequate disposal of PPE. The mismanagement and subsequent degradation of discarded PPE significantly contribute to increased non-biodegradable micro(nano)plastic (MNP) waste. This pollution has had profound adverse effects on terrestrial, marine, and aquatic ecosystems, which have been extensively of concern recently. Accumulated MNPs within aquatic organisms could serve as a potential route for human exposure when consuming seafood. This review presents a novel aspect concerning the pollution caused by MNPs, particularly remarking on their role during the pandemic and their detrimental effects on human health. These microplastic particles, through the process of fragmentation, transform into nanoparticles, persisting in the environment and posing potential hazards. The prevalence of MNP from PPE, notably masks, raises concerns about their plausible health risks, warranting global attention and comprehensive exploration. Conducting a comprehensive evaluation of the long-term effects of these processes and implementing effective management strategies is essential.

Toxicity of environmental and polystyrene plastic particles on the bivalve Corbicula fluminea: focus on the molecular responses

Among aquatic organisms, filter feeders are particularly exposed to the ingestion of microplastics (MPs) and nanoplastics (NPs). The present study investigates the effect of environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized plastic debris collected in the Garonne River (France), and polystyrene NPs (PS NPs) on the freshwater bivalve Corbicula fluminea. Organisms were exposed to plastic particles at three concentrations: 0.008, 10, and 100 μg L-1 for 21 days. Gene expression measurements were conducted in gills and visceral mass at 7 and 21 days to assess the effects of plastic particles on different functions. Our results revealed: (i) an up-regulation of genes, mainly involved in endocytosis, oxidative stress, immunity, apoptosis, and neurotoxicity, at 7 days of exposure for almost all environmental plastic particles and at 21 days of exposure for PS NPs in the gills, (ii) PS NPs at the three concentrations tested and ENV MPs at 0.008 μg L-1 induced strong down-regulation of genes involved in detoxication, oxidative stress, immunity, apoptosis, and neurotoxicity at 7 days of exposure in the visceral mass whereas ENV MPs at 10 and 100 μg L-1 and all ENV NPs induced less pronounced effects, (iii) overall, PS NPs and ENV MPs 0.008 μg L-1 did not trigger the same effects as ENV MPs 10 and 100 μg L-1 and all ENV NPs, either in the gills or the visceral mass at 7 and 21 days of exposure. This study highlighted the need to use MPs and NPs sampled in the environment for future studies as their properties induce different effects at the molecular level to living organisms.

Traversing the prevalence of microplastics in soil-agro ecosystems: Origin, occurrence, and pollutants synergies

The ubiquity of plastics in modern life has made them a significant environmental concern and a marker of the Anthropocene era. The degradation of plastics results in the formation of microplastics (MPs), which measure 5 mm or less. The coexistence of MPs with other pollutants found in sludge, water treatment plant effluents, surface water, and groundwater, shapes the environmental landscape together. Despite extensive investigation, the long-term implications of MPs in soils remain uncertain, underscoring the importance of delving into their transportation and interactions with soil biota and other contaminants. The present article provides a comprehensive overview of MPs contamination in soil, encompassing its sources, prevalence, features, and interactions with soil flora and fauna, heavy metals, and organic compounds. The sources of MPs in soil agroecosystems are mulching, composting, littering, sewage sludge, irrigation water, and fertilizer application. The concentration of MPs reported in plastic mulch, littering, and sewage sludge is 503 ± 2760 items per kg-1, 4483 ± 2315 MPs/kg, and 11,100 ± 570 per/kg. The transport of MPs in soil agroecosystems is due to their horizontal and vertical migration including biotic and abiotic mobility. The article also highlighted the analytical process, which includes sampling planning, collection, purification, extraction, and identification techniques of MPs in soil agroecosystems. The mechanism in the interaction of MPs and organic pollutants includes surface adsorption or adhesion cation bridging, hydrogen bonding, charge transfer, ligand exchange, van der Waals interactions, and ion exchange.

The power of green: Harnessing phytoremediation to combat micro/nanoplastics

Plastic pollution and its potential risks have been raising public concerns as a global environmental issue. Global plastic waste may double by 2030, posing a significant challenge to the remediation of environmental plastics. In addition to finding alternative products and managing plastic emission sources, effective removal technologies are crucial to mitigate the negative impact of plastic pollution. However, current remediation strategies, including physical, chemical, and biological measures, are unable to compete with the surging amounts of plastics entering the environment. This perspective lays out recent advances to propel both research and action. In this process, phytoaccumulation, phytostabilization, and phytofiltration can be applied to reduce the concentration of nanoplastics and submicron plastics in terrestrial, aquatic, and atmospheric environments, as well as to prevent the transport of microplastics from sources to sinks. Meanwhile, advocating for a more promising future still requires significant efforts in screening hyperaccumulators, coupling multiple measures, and recycling stabilized plastics from plants. Phytoremediation can be an excellent strategy to alleviate global micro/nanoplastic pollution because of the cost-effectiveness and environmental sustainability of green technologies.

A systematic review on the impact of micro-nanoplastics on human health: Potential modulation of epigenetic mechanisms and identification of biomarkers

Epigenetic-mediated modifications, induced by adverse environmental conditions, significantly alter an organism's physiological mechanisms. Even after elimination of the stimulus, these epigenetic modifications can be inherited through mitosis, thereby triggering transgenerational epigenetics. Plastics, with their versatile properties, are indispensable in various aspects of daily life. However, due to mismanagement, plastics have become so ubiquitous in the environment that no ecosystem on Earth is free from micro-nanoplastics (MNPs). This situation has raised profound concerns regarding their potential impact on human health. Recently, both in vivo animal and in vitro human cellular models have shown the potential to identify the harmful effects of MNPs at the genome level. The emerging epigenetic impact of MNP exposure is characterized by short-term alterations in chromatin remodelling and miRNA modulation. However, to understand long-term epigenetic changes and potential transgenerational effects, substantial and more environmentally realistic exposure studies are needed. In the current review, the intricate epigenetic responses, including the NHL-2-EKL-1, NDK-1-KSR1/2, and WRT-3-ASP-2 cascades, wnt-signalling, and TGF- β signalling, established in model organisms such as C. elegans, mice, and human cell lines upon exposure to MNPs, were systematically examined. This comprehensive analysis aimed to predict human pathways by identifying human homologs using databases and algorithms. We are confident that various parallel miRNA pathways, specifically the KSR-ERK-MAPK pathway, FOXO-Insulin cascade, and GPX3-HIF-α in humans, may be influenced by MNP exposure. This influence may lead to disruptions in key metabolic and immune pathways, including glucose balance, apoptosis, cell proliferation, and angiogenesis. Therefore, we believe that these genes and pathways could serve as potential biomarkers for future studies. Additionally, this review emphasizes the origin, dispersion, and distribution of plastics, providing valuable insights into the complex relationship between plastics and human health while elaborating on the epigenetic impacts.

Overview of the environmental risks of microplastics and their controlled degradation from the perspective of free radicals

Owing to the significant environmental threat posed by microplastics (MPs) of varying properties, MPs research has garnered considerable attention in current academic discourse. Addressing MPs in river-lake water systems, existing studies have seldom systematically revealed the role of free radicals in the aging/degradation process of MPs. Hence, this review aims to first analyze the pollution distribution and environmental risks of MPs in river-lake water systems and to elaborate the crucial role of free radicals in them. After that, the study delves into the advancements in free radical-mediated degradation techniques for MPs, emphasizing the significance of both the generation and elimination of free radicals. Furthermore, a novel approach is proposed to precisely govern the controlled generation of free radicals for MPs' degradation by interfacial modification of the material structure. Hopefully, it will shed valuable insights for the effective control and reduction of MPs in river-lake water systems.

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).

Effects of salinity on naphthalene adsorption and toxicity of polyethylene microparticles on Artemia salina

Plastic pollution in aquatic ecosystems is increasing and plastic particles may adsorb and transport a diverse array of contaminants, thereby increasing their bioavailability to biota. This investigation aimed to evaluate the effects of varying polyethylene microplastics (PE MPs) and naphthalene (NAPH) concentrations on the survival and feeding rates of the model organism, Artemia salina, as well as NAPH adsorption to microplastics at different salinity levels (17, 75, 35.5 and 52.75 g L-1) under selected climate change scenarios. Survival (48 h) and feeding rates (6 h) of A. salina were also monitored, revealing that the presence of higher PE and NAPH concentrations lead to decreased survival rates while also increasing the number and size of microplastic particles in the saline solutions. Higher PE concentrations negatively affected A. salina feeding rates and NAPH concentrations were positively correlated with particle number and size, as well as with NAPH and PE adsorption rates in solution. Our findings demonstrate that the co-occurrence of microplastics and NAPH in aquatic environments can result in detrimental zooplankton survival and feeding rate effects. Furthermore, this interaction may contribute to the accumulation of these contaminants in the environment, highlighting the need to simultaneously monitor and mitigate the presence of microplastics and organic pollutants, like NAPH, in aquatic environments.

Size-dependent deleterious effects of nano- and microplastics on sperm motility

INTRODUCTION

Growing concerns regarding the reproductive toxicity associated with daily life exposure to micro-/nano-plastics (abbreviated as MNPs) have become increasingly prevalent. In reality, MNPs exposure involves a heterogeneous mixture of MNPs of different sizes rather than a single size.

METHODS

In this study, an oral exposure mouse model was used to evaluate the effects of MNPs of four size ranges: 25-30 nm, 1-5 µm, 20-27 µm, and 125-150 µm. Adult male C57BL/6 J mice were administered environmentally relevant concentrations of 0.1 mg MNPs/day for 21 days. After that, open field test and computer assisted sperm assessment (CASA) were conducted. Immunohistochemical analyses of organ and cell type localization of MNPs were evaluated. Testicular transcriptome analysis was carried out to understand the molecular mechanisms.

RESULTS

Our result showed that MNPs of different size ranges all impaired sperm motility, with a decrease in progressive sperm motility, linearity and straight-line velocity of sperm movement. Alterations did not manifest in animal locomotion, body weight, or sperm count. Noteworthy effects were most pronounced in the smaller MNPs size ranges (25-30 nm and 1-5 µm). Linear regression analysis substantiated a negative correlation between the size of MNPs and sperm curvilinear activity. Immunohistochemical analysis unveiled the intrusions of 1-5 µm MNPs, but not 20-27 µm and 125-150 µm MNPs, into Leydig cells and testicular macrophages. Further testicular transcriptomic analysis revealed perturbations in pathways related to spermatogenesis, oxidative stress, and inflammation. Particularly within the 1-5 µm MNPs group, a heightened perturbation in pathways linked to spermatogenesis and oxidative stress was observed.

CONCLUSIONS

Our data support the size-dependent impairment of MNPs on sperm functionality, underscoring the pressing need for apprehensions about and interventions against the escalation of environmental micro-/nano-plastics contamination. This urgency is especially pertinent to small-sized MNPs.

Polystyrene nanoplastics induce apoptosis, autophagy, and steroidogenesis disruption in granulosa cells to reduce oocyte quality and fertility by inhibiting the PI3K/AKT pathway in female mice

BACKGROUND

Nanoplastics (NPs) are emerging pollutants that pose risks to living organisms. Recent findings have unveiled the reproductive harm caused by polystyrene nanoparticles (PS-NPs) in female animals, yet the intricate mechanism remains incompletely understood. Under this research, we investigated whether sustained exposure to PS-NPs at certain concentrations in vivo can enter oocytes through the zona pellucida or through other routes that affect female reproduction.

RESULTS

We show that PS-NPs disrupted ovarian functions and decreased oocyte quality, which may be a contributing factor to lower female fertility in mice. RNA sequencing of mouse ovaries illustrated that the PI3K-AKT signaling pathway emerged as the predominant environmental information processing pathway responding to PS-NPs. Western blotting results of ovaries in vivo and cells in vitro showed that PS-NPs deactivated PI3K-AKT signaling pathway by down-regulating the expression of PI3K and reducing AKT phosphorylation at the protein level, PI3K-AKT signaling pathway which was accompanied by the activation of autophagy and apoptosis and the disruption of steroidogenesis in granulosa cells. Since PS-NPs penetrate granulosa cells but not oocytes, we examined whether PS-NPs indirectly affect oocyte quality through granulosa cells using a granulosa cell-oocyte coculture system. Preincubation of granulosa cells with PS-NPs causes granulosa cell dysfunction, resulting in a decrease in the quality of the cocultured oocytes that can be reversed by the addition of 17β-estradiol.

CONCLUSIONS

This study provides findings on how PS-NPs impact ovarian function and include transcriptome sequencing analysis of ovarian tissue. The study demonstrates that PS-NPs impair oocyte quality by altering the functioning of ovarian granulosa cells. Therefore, it is necessary to focus on the research on the effects of PS-NPs on female reproduction and the related methods that may mitigate their toxicity.

Combined contamination of microplastic and antibiotic alters the composition of microbial community and metabolism in wheat and maize rhizosphere soil

The widespread application of antibiotics and plastic films in agriculture has led to new characteristics of soil pollution. The impacts of combined contamination of microplastics and antibiotics on plant growth and rhizosphere soil bacterial community and metabolisms are still unclear. We conducted a pot experiment to investigate the effects of polyethylene (0.2%) and norfloxacin/doxycycline (5 mg kg-1), as well as the combination of polyethylene and antibiotics, on the growth, rhizosphere soil bacterial community and metabolisms of wheat and maize seedlings. The results showed that combined contamination caused more serious damage to plant growth than individual contamination, and aggravated root oxidative stress responses. The diversity and structure of soil bacterial community were not markedly altered, but the composition of the bacterial community, soil metabolisms and metabolic pathways were altered. The co-occurrence network analysis indicated that combined contamination may inhibit the growth of wheat and maize seedings by simplifying the interrelationships between soil bacteria and metabolites, and altering the relative abundance of specific bacteria genera (e.g. Kosakonia and Sphingomonas) and soil metabolites (including sugars, organic acids and amino acids). The results help to elucidate the potential mechanisms of phytotoxicity of the combination of microplastic and antibiotics.