Environmental exposure to microplastics: An overview on possible human health effects

Polystyrene micro- and nanoplastics induce gastric toxicity through ROS mediated oxidative stress and P62/Keap1/Nrf2 pathway

Microplastics (MPs) exist widely in the environment and can enter the human body indirectly through the food chain or directly through inhalation or ingestion. The primary organ that MPs contaminated food or water enters the human body through the digestive tract is the stomach. However, at present, the effects of MPs on the stomach and the related mechanism remain unclear. In this study, our results indicated that 50 nm and 250 nm polystyrene MPs (PS-MPs) at environmental related dose significantly decreased stomach organ coefficient, inhibited gastric juice secretion and mucus secretion, disrupted gastric barrier function and suppressed antioxidant ability in mice. In vitro experiments showed that PS-MPs inhibited cell viability, increased ROS generation, and induced apoptosis through mitochondria-dependent pathway. Simultaneously, PS-MPs also decreased mitochondrial membrane potential, ATP level, disrupted mitochondrial kinetic homeostasis, and activated P62 / Nrf2 / Keap1 pathway. Furthermore, blocking ROS (NAC) partially alleviated ROS and apoptosis caused by PS-MPs. Based on above findings, the potential adverse outcome pathway (AOP) of PS-MPs-caused gastric toxicity was proposed which provides a new insight into the risk assessment of MP related gastric damage. Our study unveils the gastric injury induced by PS MPs is dependent on ROS - mediated P62 / Nrf2 / Keap1 signaling pathway, and provides scientific basis for further exploration the mechanism of gastric toxicity of PS MPs.

Identification and physico-chemical characterization of microplastics in marine aerosols over the northeast Arabian Sea

Microplastics (MPs) in the atmosphere can undergo long-range transport from emission regions to pristine terrestrial and oceanic ecosystems. Due to their inherent toxic and hazardous characteristics, MPs pose serious risks to both human well-being and the equilibrium of ecosystem. The present study outlines the comprehensive characterization, spanning physical and chemical attributes of MPs associated with atmospheric aerosols. Total suspended particulates (TSPs) were collected on a quartz fibre filter by operating a high-volume sampler for 24 h during distinct years (March, 2016 and November, 2020) at a coastal location in the northeast Arabian Sea. Subsequent to the sampling, a series of techniques were applied including density separation. The assessment and scrutiny of the MPs was carried out using stereo-zoom microscopy with supplementary validation using advanced fluorescence microscopy for enhanced precision in identification. Our comparative assessment suggests peroxide treatment followed by density separation could be a robust procedure for the definitive identification and characterization of MPs in the atmosphere. Average total abundance of MPs was found to be 1.30 ± 0.14 n/m3 in 2016 and 1.46 ± 0.12 n/m3 in 2020 with fibres, fragments and films having similar relative contributions (41 %, 31 %, 28 % in 2016 and 40 %, 35 %, 25 % in 2020). Fibres were found to be dominant morphotype followed by fragments and films over the coastal region of the Arabian Sea. In order to unravel the detailed chemical nature of these MPs, spectral analysis using μ-FTIR was carried out. The outcome of the analysis showed prevailing polymers as polyvinyl chloride and polymethyl methacrylate (50545 %) as dominant polymers followed by polyester (15 %), styrene butyl methacrylate (11 %), and polyacetal (9 %). MPs present in the vicinity of the Arabian Sea have potential to supply nutrients and toxicants, consequently can contribute to the modulation of the surface water biogeochemical processes.

Micro/nanoplastics: Critical review of their impacts on plants, interactions with other contaminants (antibiotics, heavy metals, and polycyclic aromatic hydrocarbons), and management strategies

Microplastic/nanoplastics (MPs/NPs) contamination is not only emerging threat to the agricultural system but also constitute global hazard to the environment worldwide. Recent review articles have addressed the environmental distribution of MPs/NPs and their single-exposure phytotoxicity in various plant species. However, the mechanisms of MPs/NPs-induced phytotoxicity in conjunction with that of other contaminants remain unknown, and there is a need for strategies to ameliorate such phytotoxicity. To address this, we comprehensively review the sources of MPs/NPs, their uptake by and effects on various plant species, and their phytotoxicity in conjunction with antibiotics, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and other toxicants. We examine mechanisms to ameliorate MP/NP-induced phytotoxicity, including the use of phytohormones, biochar, and other plant-growth regulators. We discuss the effects of MPs/NPs -induced phytotoxicity in terms of its ability to inhibit plant growth and photosynthesis, disrupt nutrient metabolism, inhibit seed germination, promote oxidative stress, alter the antioxidant defense system, and induce genotoxicity. This review summarizes the novel strategies for mitigating MPs/NPs phytotoxicity, presents recent advances, and highlights research gaps, providing a foundation for future studies aimed at overcoming the emerging problem of MPs/NPs phytotoxicity in edible crops.

Degradation and potential metabolism pathway of polystyrene by bacteria from landfill site

Microplastics pollution has garnered significant attention in recent years. The unique cross-linked structure of polystyrene microplastics makes them difficult to biodegrade. In this study, we investigated the microbial community in landfill soil that has the ability to degrade polystyrene, as well as two isolated strains, named Lysinibacillus sp. PS-L and Pseudomonas sp. PS-P. The maximum weight loss of polystyrene film and microplastic in 30 days is 2.25% and 6.99% respectively. The water contact angle of polystyrene film decreased by a maximum of 35.70% during biodegradation. The increase in hydrophilicity is attributed to the oxidation reaction and formation of hydroxyl groups during the degradation of polystyrene. The carbon and oxygen element contents of polystyrene decreased and increased by a maximum of 3.81% and 0.79% respectively. The peak intensity changes at wavelengths of 3285-3648 cm-1 and 1652 cm-1 in Fourier transform infrared spectroscopy confirmed the formation of hydroxyl and carbonyl groups. Furthermore, quantitative PCR revealed the gene expression levels of alkane monooxygenase and alcohol dehydrogenase were upregulated by 8.8-fold and 8.5-fold respectively in PS biodegradation. Additionally, genome annotation of Pseudomonas sp. PS-P identified nine genes associated with polystyrene metabolism. These findings highlight Pseudomonas sp. PS-P as a potential candidate strain for polystyrene degradation enzymes or genes. Thus, they lay the groundwork for understanding the potential metabolic mechanisms and pathways involved in polystyrene degradation.

Microplastics in oral healthcare products (OHPs) and their environmental health risks and mitigation measures

The environmental input of microplastics from personal care products has received significant attention; however, less focus has been paid to oral healthcare products. The present study assessed the occurrence of microplastics in commercially available oral healthcare products such as toothbrushes, toothpastes, toothpowder, mouthwash, dental floss, and mouth freshener spray that have a pan-India distribution. The extracted microplastics were quantified and characterised using a microscope and ATR-FTIR. All products showed microplastic contamination, where toothbrushes showed the maximum particles (30-120 particles/brush) and mouth freshener sprays (0.2-3.5 particles/ml) had the least abundance. Fragments, fibres, beads, and films were the various shapes of microplastics observed, where fragments (60%) were dominant. Various colours such as pink, green, blue, yellow, black, and colourless were observed, where colourless (40%) particles were dominant. Microplastics were categorized into three sizes: <0.1 mm (63%), 0.1-0.3 mm (35%), and >0.3 mm (2%). Four major types of polymers, such as polyethylene (52%), polyamide (30%), polyethylene terephthalate (15%), and polybutylene terephthalate (3%), were identified. Risk assessment studies such as Daily Microplastics Emission (DME), Annual Microplastics Exposure (AME), and Polymer Hazard Index (PHI) were carried out. The DME projection for India was the highest for mouthwash (74 billion particles/day) and the least for mouth freshener sprays (0.36 billion particles/day). The AME projection for an individual was the highest in toothbrushes (48,910 particles ind.-1 yr.-1) and the least in mouth freshener sprays (111 particles ind.-1 yr.-1). PHI shows that the identified polymers fall under the low-to high-risk categories. This study forecasts the community health risks linked to microplastics in oral healthcare products and suggests mitigation strategies. It has the potential to shape environmental policy development in response.

Microplastics as carriers of toxic pollutants: Source, transport, and toxicological effects

Microplastic pollution has emerged as a new environmental concern due to our reliance on plastic. Recent years have seen an upward trend in scholarly interest in the topic of microplastics carrying contaminants; however, the available review studies have largely focused on specific aspects of this issue, such as sorption, transport, and toxicological effects. Consequently, this review synthesizes the state-of-the-art knowledge on these topics by presenting key findings to guide better policy action toward microplastic management. Microplastics have been reported to absorb pollutants such as persistent organic pollutants, heavy metals, and antibiotics, leading to their bioaccumulation in marine and terrestrial ecosystems. Hydrophobic interactions are found to be the predominant sorption mechanism, especially for organic pollutants, although electrostatic forces, van der Waals forces, hydrogen bonding, and pi-pi interactions are also noteworthy. This review reveals that physicochemical properties of microplastics, such as size, structure, and functional groups, and environmental compartment properties, such as pH, temperature, and salinity, influence the sorption of pollutants by microplastic. It has been found that microplastics influence the growth and metabolism of organisms. Inadequate methods for collection and analysis of environmental samples, lack of replication of real-world settings in laboratories, and a lack of understanding of the sorption mechanism and toxicity of microplastics impede current microplastic research. Therefore, future research should focus on filling in these knowledge gaps.

Environmentally persistent free radicals on photoaged microplastics from disposable plastic cups induce the oxidative stress-associated toxicity

Microplastics (MPs) are ubiquitous environmental contaminants that exerting multiple toxicological effects. Most studies have focused primarily on the models of unaged MPs and lack environmental relevance. The generation and toxicity of environmentally persistent free radicals (EPFRs) on photoaging MPs from disposable plastic cups (DPC-MPs) have not been well studied. Here, the formation of EPFRs on photoaged DPC-MPs and their toxic effects in nematodes were investigated. UV irradiation generated EPFRs, which influenced the characterization of DPC-MPs. Exposure to photoaged DPC-MPs at environmentally relevant concentrations （100-1000 μg/L） reduced the locomotion behavior, body length, and brood size. The Reactive oxygen species (ROS) production, lipofuscin accumulation, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were increased along with the downregulation of the expression levels of associated genes, such as clk-1, clt-1, and gst-4，in nematodes. Moreover, the toxicity and oxidative stress response of nematodes were significantly inhibited due to N-acetyl-l-cysteine (NAC). Pearson's correlation analysis revealed that the oxidative stress was significantly associated with adverse physiological effects. Therefore, EPFRs on photoaged DPC-MPs cause toxicity in nematodes, and oxidative stress is important for regulating toxicity. This study offers novel insights into the potential risks of DPC-MPs under UV irradiation, highlighting the need to consider the role of EPFRs in toxicity assessments of DPC-MPs.

Microplastic pollution on historic facades: Hidden 'sink' or urban threat?

Despite the increasing concerns surrounding the health and environmental risks of microplastics (MPs), the research focus has primarily been on their prevalence in air and the oceans, consequently neglecting their presence on urban facades, which are integral to our everyday environments. Therefore, there is a crucial knowledge gap in comprehending urban MP pollution. Our pioneering interdisciplinary study not only quantifies but also identifies MPs on historic facades, revealing their pervasive presence in a medium-sized urban area in the UK. In this case study, we estimated a mean density of 975,000 fibres/m^2 (0.10 fibres/mm^2) for fibre lengths between 30 and 1000 μm with a ratio of 1:5 for natural to artificial fibres. Our research identifies three groups of fibre length frequencies across varied exposure scenarios on the investigated urban facade. Sheltered areas (4m height) show a high prevalence of 60-120 μm and 180-240 μm fibres. In contrast, less sheltered areas at 3m exhibit lower fibre frequencies but similar lengths. Notably, the lowest area (2-1.5m) features longer fibres (300-1000 μm), while adjacent area S, near a faulty gutter, shows no fibres, highlighting the impact of exposure, altitude, and environmental variables on fibre distribution on urban facades. Our findings pave one of many necessary paths forward to determine the long-term fate of these fibres and provoke a pertinent question: do historic facades serve as an urban 'sink' that mitigates potentially adverse health impacts or amplifies the effects of mobile microplastics? Addressing MP pollution in urban areas is crucial for public health and sustainable cities. More research is required to understand the multi-scale factors behind MP pollution in large cities and to find mitigation strategies, paving the way for effective interventions and policies against this growing threat.

A comprehensive review on the source, ingestion route, attachment and toxicity of microplastics/nanoplastics in human systems

Microplastics (MPs)/nanoplastics (NPs) are widely found in the natural environment, including soil, water and the atmosphere, which are essential for human survival. In the recent years, there has been a growing concern about the potential impact of MPs/NPs on human health. Due to the increasing interest in this research and the limited number of studies related to the health effects of MPs/NPs on humans, it is necessary to conduct a systematic assessment and review of their potentially toxic effects on human organs and tissues. Humans can be exposed to microplastics through ingestion, inhalation and dermal contact, however, ingestion and inhalation are considered as the primary routes. The ingested MPs/NPs mainly consist of plastic particles with a particle size ranging from 0.1 to 1 μm, that distribute across various tissues and organs within the body, which in turn have a certain impact on the nine major systems of the human body, especially the digestive system and respiratory system, which are closely related to the intake pathway of MPs/NPs. The harmful effects caused by MPs/NPs primarily occur through potential toxic mechanisms such as induction of oxidative stress, generation of inflammatory responses, alteration of lipid metabolism or energy metabolism or expression of related functional factors. This review can help people to systematically understand the hazards of MPs/NPs and related toxicity mechanisms from the level of nine biological systems. It allows MPs/NPs pollution to be emphasized, and it is also hoped that research on their toxic effects will be strengthened in the future.

Microplastic contamination in the agricultural soil-mitigation strategies, heavy metals contamination, and impact on human health: a review

Microplastic pollution has emerged as a critical global environmental issue due to its widespread distribution, persistence, and potential adverse effects on ecosystems and human health. Although research on microplastic pollution in aquatic environments has gained significant attention. However, a limited literature has summarized the impacts of microplastic pollution the agricultural land and human health. Therefore, In the current review, we have discussed how microplastic(s) affect the microorganisms by ingesting the microplastic present in the soil, alternatively affecting the belowground biotic and abiotic components, which further elucidates the negative effects on the above-ground properties of the crops. In addition, the consumption of these crops in the food chain revealed a potential risk to human health throughout the food chain. Moreover, microplastic pollution has the potential to induce a negative impact on agricultural production and food security by altering the physiochemical properties of the soil, microbial population, nutrient cycling, and plant growth and development. Therefore, we discussed in detail the potential hazards caused by microplastic contamination in the soil and through the consumption of food and water by humans in daily intake. Furthermore, further study is urgently required to comprehend how microplastic pollution negatively affects terrestrial ecosystems, particularly agroecosystems which drastically reduces the productivity of the crops. Our review highlights the urgent need for greater awareness, policy interventions, and technological solutions to address the emerging threat of microplastic pollution in soil and plant systems and mitigation strategies to overcome its potential impacts on human health. Based on existing studies, we have pointed out the research gaps and proposed different directions for future research.

Estimated exposure to microplastics through national and local brands of bottled water in Central India

Microplastics (MPs) are ubiquitous pollutants that affect various environmental matrices, including air, water, soil, food, and beverages. In India, there is limited research on microplastics in bottled drinking water, which is a significant route of MP exposure to the human body. To date, the data on the occurrence of MPs in national and local bottled water brands have not been studied and compared. Therefore, the current study focuses on the contamination of MPs in bottled water from different national and local brands procured from the market of Nagpur, India. The MPs were observed in all the analyzed samples. It was observed that the local bottled water showed higher MP contamination compared to national bottled water, with MP concentrations of 212 ± 100 MPs/L and 72 ± 36 MPs/L, respectively. The MPs were identified and characterized using microscopic and attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) analysis, revealing that the dominant MP particles were fragments (71%), followed by fibers (23%), and others (6%). Among the observed particles, 50% of particles were black colored, followed by transparent (16%), red (13%), orange (8%), green (3%), blue (5%), and yellow (5%). The predominant polymer types were polyethylene (PE) and polyethylene terephthalate (PET). Overall, the pollution load indices suggested a moderate level of contamination in bottled water samples. Furthermore, the estimated annual human exposure to MPs was calculated as 5186 ± 3751 p/kg-bw/year for children and 1482 ± 1072 p/kg-bw/year for adults, making it a significant route of human exposure to MPs.

Influence of polyethylene terephthalate (PET) microplastic on selected active substances in the intramural neurons of the porcine duodenum

BACKGROUND

Currently, society and industry generate huge amounts of plastics worldwide. The ubiquity of microplastics is obvious, but its impact on the animal and human organism remains not fully understood. The digestive tract is one of the first barriers between pathogens and xenobiotics and a living organism. Its proper functioning is extremely important in order to maintain homeostasis. The aim of this study was to determine the effect of microplastic on enteric nervous system and histological structure of swine duodenum. The experiment was carried out on 15 sexually immature gilts, approximately 8 weeks old. The animals were randomly divided into 3 study groups (n = 5/group). The control group received empty gelatin capsules once a day for 28 days, the first research group received daily gelatin capsules with polyethylene terephthalate (PET) particles as a mixture of particles of various sizes (maximum particle size 300 µm) at a dose of 0.1 g/animal/day. The second study group received a dose ten times higher-1 g/animal/day.

RESULTS

A dose of 1 g/day/animal causes more changes in the enteric nervous system and in the histological structure of duodenum. Statistically significant differences in the expression of cocaine and amphetamine regulated transcript, galanin, neuronal nitric oxide synthase, substance P, vesicular acetylcholine transporter and vasoactive intestinal peptide between control and high dose group was noted. The histopathological changes were more frequently observed in the pigs receiving higher dose of PET.

CONCLUSION

Based on this study it may be assumed, that oral intake of microplastic might have potential negative influence on digestive tract, but it is dose-dependent.

Depth significantly affects plastisphere microbial evenness, assembly and co-occurrence pattern but not richness and composition

Microplastics have become one of the hot concerns of global marine pollution. In recent years, diversity and abiotic influence factors of plastisphere microbial communities were well documented, but our knowledge of their assembly mechanisms and co-occurrence patterns remains unclear, especially the effects of depth on them. Here, we collected microorganisms on microplastics to investigate how ocean depth affects on microbial diversity, community composition, assembly processes and co-occurrence patterns. Our results indicated that there were similar microbial richness and community compositions but microbial evenness and unique microbes were obviously different in different ocean layers. Our findings also demonstrated that deterministic processes played dominant roles in the assembly of the mesopelagic plastisphere microbial communities, while the bathypelagic microbial community assembly was mainly shaped by stochastic processes. In addition, the co-occurrence networks suggested that the relationships between microorganisms in the mesopelagic layer were more complex and stable than those in the bathypelagic layer. Simultaneously, we also found that Proteobacteria and Actinobacteriota were the most abundant keystones which played important roles in microbial co-occurrence networks at both layers. This study enhanced our understanding of microbial diversity, assembly mechanism, and co-occurrence pattern on plastisphere surfaces, and provided useful insights into microorganisms capable of degrading plastics and microbial remediation.

Polystyrene microplastics induce kidney injury via gut barrier dysfunction and C5a/C5aR pathway activation

Microplastic is an emerging environmental pollutant with potential health risks. Recent studies have shown that microplastic could impair gut homeostasis in mammals. Although it has been widely demonstrated that gut dyshomeostasis could impact renal health through the gut-kidney axis, the effects of microplastic-induced gut dyshomeostasis on renal health and underlying mechanisms are still largely unknown. In the current work, we found that polystyrene microplastics (PS-MPs) treatment impaired the gut barrier, increased urinary complement-activated product C5a levels and renal C5aR expression, leading to chronic kidney disease-related symptoms in mice. Restoring the gut barrier using an antibiotic mixture effectively alleviated PS-MPs-induced kidney injury, indicating the involvement of the gut-kidney axis in PS-MPs-induced renal injury. Moreover, it also mitigated PS-MPs-induced alterations in urinary C5a levels and renal C5aR expression, suggesting that the renal C5a/C5aR pathway might be involved in PS-MPs' impacts on the gut-kidney axis. Further experiments using a C5aR inhibitor, PMX53, verified the vital role of renal C5a/C5aR pathway activation in the development of kidney injury induced by PS-MPs. Collectively, our results suggest that PS-MPs induce kidney injury in mice by impairing the gut barrier, increasing C5a levels, and ultimately activating the renal C5a/C5aR pathway, highlighting the crucial role of the gut-kidney axis in PS-MPs-induced kidney injury.

Interactions between microplastics and Culex sp. larvae in wastewater

Microplastics (MPs) are a growing issue because they endanger both aquatic organisms and humans. Studies have indicated that wastewater treatment plants (WWTPs) are one of the major contributors to MPs in the environment. However, studies on the abundance of MP contamination in WWTPs and its transmission into aquatic organisms are still scarce, especially in Egypt. The goal of this study was to examine the temporal fluctuations in the distribution of MPs in surface water and the dominant macroinvertebrate fauna (Culex sp. larvae) in a fixed wastewater basin in Sohag Governorate, Egypt. The average of MPs in the surface water was 3.01 ± 0.9 particles/L. The results indicated to seasonal variation of MP abundance in the wastewater basin that was significantly higher in winter than in the other seasons. The risk index for polymers (H), pollution load index (PLI), and potential ecological risk index (RI) were used to assess the degree of MP contamination. The basin has moderate H values (<1000) because of the presence of polymers with moderate hazard scores such as polyester (PES), polyethylene (PE), and polypropylene (PP). According to the PLI values, surface water is extremely contaminated with MPs (PLI: 88 to 120). The RI values of surface water showed higher ecological risk (level V). MPs in Culex sp. larvae were seasonally changed with an 85% detection rate, and an abundance average of 0.24 ± 0.65 particles/ind, MP concentration in Culex sp. larvae was influenced by the MP characters (shape, color, and polymer). The larvae of Culex sp. showed a greater preference for black and red fibrous polyester (PES) with sizes (<1000 μm) of MPs. These findings suggest that Culex sp. larvae prefer ingesting MPs that resemble their food. It is possible to overestimate Culex sp.'s preference for lower sizes because of their catabolism of MPs. To better understand the preferences of Culex sp. larvae for MPs, further controlled trials should be conducted. PRACTITIONER POINTS: Wastewater is highly contaminated with microplastics (MPs) in the different seasons. First report of detection of the seasonal abundance of MP in Culex sp. larvae. Culex sp. larvae showed a stronger feeding preference for MPs with specific characteristics. Smaller size and blue polyester fibers were the dominant characteristics of MPs in wastewater.

Understanding the mechanistic roles of microplastics combined with heavy metals in regulating ferroptosis: Adding new paradigms regarding the links with diseases

As a new type of pollutant, microplastics (MPs) commonly exist in today's ecosystems, causing damage to the ecological environment and the health of biological organisms, including human beings. MPs can function as carriers of heavy metals (HMs) to aggravate the enrichment of HMs in important organs of organisms, posing a great threat to health. Ferroptosis, a novel process for the regulation of nonapoptotic cell death, has been shown to be closely related to the occurrence and processes of MPs and HMs in diseases. In recent years, some HMs, such as cadmium (Cd), iron (Fe), arsenic (As) and copper (Cu), have been proven to induce ferroptosis. MPs can function as carriers of HMs to aggravate damage to the body. This damage involves oxidative stress, mitochondrial dysfunction, lipid peroxidation (LPO), inflammation, endoplasmic reticulum stress (ERS) and so on. Therefore, ferroptosis has great potential as a therapeutic target for diseases induced by MPs combined with HMs. This paper systematically reviews the potential effects and regulatory mechanisms of MPs and HMs in the process of ferroptosis, focusing on the mitochondrial damage, Fe accumulation, LPO, ERS and inflammation caused by MPs and HMs that affect the regulatory mechanism of ferroptosis, providing new insights for research on regulating drugs and for the development of ferroptosis-targeting therapy for Alzheimer's disease, Parkinson's disease, cancer and cardiovascular disease.

Mechanistic understanding on the uptake of micro-nano plastics by plants and its phytoremediation

Contaminated soil is one of today's most difficult environmental issues, posing serious hazards to human health and the environment. Contaminants, particularly micro-nano plastics, have become more prevalent around the world, eventually ending up in the soil. Numerous studies have been conducted to investigate the interactions of micro-nano plastics in plants and agroecosystems. However, viable remediation of micro-nano plastics in soil remains limited. In this review, a powerful in situ soil remediation technology known as phytoremediation is emphasized for addressing micro-nano-plastic contamination in soil and plants. It is based on the synergistic effects of plants and the microorganisms that live in their rhizosphere. As a result, the purpose of this review is to investigate the mechanism of micro-nano plastic (MNP) uptake by plants as well as the limitations of existing MNP removal methods. Different phytoremediation options for removing micro-nano plastics from soil are also described. Phytoremediation improvements (endophytic-bacteria, hyperaccumulator species, omics investigations, and CRISPR-Cas9) have been proposed to enhance MNP degradation in agroecosystems. Finally, the limitations and future prospects of phytoremediation strategies have been highlighted in order to provide a better understanding for effective MNP decontamination from soil.

[Global environmental changes and the epithelial barrier hypothesis]

BACKGROUND

The global burden of noncommunicable diseases (NCD) has seen a strong increase in recent decades and attributable to the influence of environmental factors. For a multitude of diseases an association with epithelial barrier damage has been reported.

OBJECTIVE

This article provides an overview of the health effects of environmental pollution in the context of the epithelial barrier hypothesis of Cezmi Akdis. Additionally, exemplary mechanisms of a barrier damage are described. Finally, possible preventive and therapeutic consequences are discussed.

MATERIAL AND METHODS

The PubMed database was searched for the relevant topics and selected literature was reviewed.

RESULTS

A wide variety of substances can damage the epithelial barriers of the skin, lungs and gastrointestinal tract. The rise in the prevalences of atopic diseases could (partly) be due to an increased exposure to barrier-damaging substances, such as particulate matter and laundry detergents. A possible pathogenetic mechanism is the initiation and maintenance of an immune response by subepithelial penetration of microorganisms through damaged epithelia.

CONCLUSION

Based on the epithelial barrier hypothesis new therapeutic and prevention strategies can be developed. The regulation of hazardous chemicals and the fight against environmental pollution and climate change are necessary to reduce the burden of disease.

Suspected sources of microplastics and nanoplastics: Contamination from experimental reagents and solvents

There is an increasing concern about the potential effects of microplastics (MPs) and nanoplastics on human health and other organisms. For the separation and detection of MPs, there are various approaches, and the distinct procedures led to different results. However, the presence of MPs in the reagents was not addressed, which could cause false and/or inaccurate results during MPs detection. In this study, the chemical reagents commonly used for the separation and detection of MPs were selected to ascertain whether these reagents introduce MPs. It was shown that a large number of MPs were detected in the reagent and solvent samples. The largest number of MPs (>1 μm) was detected in the KOH reagent, with the abundance of 3070 items/g. The order of MPs abundance in the selected reagents was: KOH > NaCl > CaCl2 > SDS > NaI > H2O2. The types of MPs were the same as the body and stopper of the reagent packaging bottles. MPs size detected in reagent bottles was primarily smaller than 10 μm. The abundance of MPs in the reagents were independent of their purity, however, there was a certain difference in MPs abundance in reagents from different manufacturers. Furthermore, the presence of nanoplastics (< 1 μm) was verified in the reagents through Py-GCMS, with the abundance (39.47-43.01 mg/kg) higher than that of MPs. The obtained results in this study raised specific requirements and cautions for MPs and nanoplastics related research in terms of quality control. Also, this work can facilitate a more accurate assessment of MPs concentrations in the environment.

Microplastics in the Asia-Pacific Region in the Plasticene Era: Exposures and Health Risks

Within the broader Anthropocene Epoch resides the Plasticene Era, where humans are subjected pervasively to nano- and microplastics (NMPs). Human's widespread exposure with NMPs occurs through the air we breathe, water we drink, and food we eat. NMP sources are wide and varied; atmospheric NMPs are largely attributed to fibres from car tyres and synthetic clothing, while particles from food packaging, personal care products, and plastic manufacturing contribute significantly to food and water contamination. NMPs have become inherent within the human body and have been found in every organ. As such, the evidence base around adverse health effects is fragmented but growing. This article presents a mini-review and report of sessions presented about NMPs at the 19th International Conference of the Pacific Basin Consortium for Environment and Health, held on Jeju Island, in 2022. Abundant evidence of substantial exposure to NMPs in the Asia-Pacific region has been exhibited. Addressing this issue necessitates the collaboration of policymakers, manufacturers, and researchers to develop safer alternatives and implement mitigation and remediation strategies. The ongoing development of a new United Nations-led global plastic treaty presents a crucial opportunity that must be acted on and not be compromised.

Environmentally Relevant Concentrations of Microplastic Exposure Cause Cholestasis and Bile Acid Metabolism Dysregulation through a Gut-Liver Loop in Mice

The massive production of plastics causes the ubiquitous existence of microplastics (MPs) in the biota, therefore, posing exposure risks and potential health concerns to human beings. However, the exact mechanisms of MPs-induced toxicities and abnormalities are largely unknown. In this study, we developed a mouse model of gavage polystyrene microplastics (PS MPs) for 30 days. We found that PS MPs can damage the intestinal barrier, accumulate in the liver tissue, and cause injury. The liver and intestine are both highly associated with bile acid (BA) metabolism. Indeed, we found that PS MPs dysregulate BA synthesis and efflux-related gene expression in the liver, causing cholestasis. Tandemly, PS MPs alter the ratio of primary to secondary BA in the feces by affecting the composition of the intestinal flora. At last, PS MPs alter mice's fecal BA profile, which affects normal BA metabolism. Taken together, the present study provides robust data on the mechanism of toxicity of MPs causing the disturbance of BA metabolism via a 4-step gut-liver loop.

Connecting the Dots: Livestock Animals as Missing Links in the Chain of Microplastic Contamination and Human Health

Plastic pollution is a global diffuse threat, especially considering its fragmentation into microplastics (MPs) and nanoplastics (NPs). Since the contamination of the aquatic environment is already well studied, most studies have now focused on the soil. Moreover, the number of studies on the exposure routes and toxic effects of MNPs in humans is continuously increasing. Although MNPs can cause inflammation, cytotoxicity, genotoxicity and immune toxicity in livestock animals, which can accumulate ingested/inhaled plastic particles and transfer them to humans through the food chain, research on this topic is still lacking. In considering farm animals as the missing link between soil/plant contamination and human health effects, this paper aims to describe their importance as carriers and vectors of MNP contamination. As research on this topic is in its early stages, there is no standard method to quantify the amount and the characteristics of MNPs in different matrices. Therefore, the creation of a common database where researchers can report data on MNP characteristics and quantification methods could be helpful for both method standardization and the future training of an AI tool for predicting the most abundant/dangerous polymer(s), thus supporting policy decisions to reduce plastic pollution and perfectly fitting with One Health principles.

Microplastics exposure induced and exacerbated the development of systemic lupus erythematosus in mice

Environmental exposure may function as a contributing risk factor in the development of systemic lupus erythematosus (SLE). Recently, the global issue of microplastics (MPs) pollution has garnered increasing concern, yet its potential impact on SLE remains unexplored. This study seeks to elucidate the ramifications of MPs exposure on lupus manifestations in spontaneous lupus MRL/lpr mice and normal C57L/6 mice. MPs exposure demonstrated the capacity to induce lupus-like symptoms in C57BL/6 mice and exacerbate lupus symptoms in MRL/lpr mice. This was manifested by MPs triggering abnormal elevation of spleen DN T, plasma cells, serum anti-dsDNA, ANA, IL-6, and TNF-α, coupled with a reduction in spleen CD4+/CD8+ cell ratio, and impairment in renal pathology. Moreover, a 4D-DIA quantitative proteomic analysis was employed to unveil substantial alterations in renal proteins attributed to MPs exposure. The findings indicated that the KEGG pathways significantly enriched by MPs-associated different proteins in C57BL/6 mice were closely aligned with the enriched KEGG pathways associated with lupus. Unlike C57BL/6 mice, there were no significantly enriched KEGG pathways identified among the MPs-associated different proteins in MRL/lpr mice. In addition, proteins related to the SLE pathway illuminated that MPs exposure induced renal damage through activation of MHCII and histone H3, culminating in the production of MAC in both C57BL/6 and MRL/lpr mice. However, a specific elevation in cathepsin and elastase caused by MPs was observed in C57BL/6 mice but not in MRL/lpr mice. This study represents a significant stride in bridging the existing knowledge gap pertaining to the intricate relationship between MPs exposure and the development of SLE.

A catchment-wide microplastic pollution investigation of the Yangtze River: The pollution and ecological risk of tributaries are non-negligible

The Yangtze River is an important global channel for plastics and microplastics (MPs) to enter the sea. However, the existing research on MPs in the Yangtze River has primarily focused on the mainstream region, without regarding the occurrence, spatial distribution, and ecological risks associated with tributaries, as well as their relationship with the mainstream. To address this knowledge gap, we conducted a large-scale catchment-wide investigation of the surface water in the Yangtze River, encompassing MPs (48 µm-5 mm) of the mainstream and 15 important tributaries. Tributaries and upstream regions exhibited relatively higher levels of MPs compared with the mainstream and different sections of the river. The distribution of MPs is primarily influenced by the emission of arable land and the pH of water. Notably, the upstream tributary areas demonstrated the highest ecological risks associated with MPs. Further analysis highlighted that the tributaries accounted for a contribution ranging from 16% to 67% in quantity and from 14% to 90% in mass of the microplastics observed in the mainstream. Our results suggest that the pollution of tributaries and their associated ecological risk migration must be effectively regulated.

Microplastics elicit an immune-agitative state in coral

Microplastic pollution in the ocean is a major problem, as its pervasiveness elicits concerns the health impacts microplastics may have on marine life (such as reef-building corals). As a primary endpoint, the organismal lipidome can define the weakening of fitness and reveal the physiological context of adverse health effects in organisms. To gain insight into the effects of microplastics on coral health, lipid profiling was performed via an untargeted lipidomic approach on the coral Turbinaria mesenterina exposed to ~10 μm polystyrene microparticles for 10 days. Considerable microplastic accumulation and obvious effects relating with immune activation were observed in the coral treated with a near environmentally relevant concentration of microplastics (10 μg/L); however, these effects were not evident in the high level (100 μg/L) treatment group. In particular, increased levels of membrane lipids with 20:4 and 22:6 fatty acid chains reallocated from the triacylglycerol pool were observed in coral host cells and symbiotic algae, respectively, which could upregulate immune activity and realign symbiotic communication in coral. High levels of polyunsaturation can sensitize the coral cell membrane to lipid peroxidation and increase cell death, which is of greater concern; additionally, the photoprotective capacity of symbiotic algae was compromised. As a result, coral physiological functions were altered. These results show that, realistic levels of microplastic pollution can affect coral health and should be a concern.

Mechanistic insight into the role of typical microplastics in chlorination disinfection: Precursors and adsorbents of both MP-DOM and DBPs

Microplastics (MPs) in drinking water are predominantly < 10 µm. The leaching of MPs derived dissolved organic matters (MP-DOM) from 5 µm polypropylene MPs (PP-MPs) and polystyrene MPs (PS-MPs) and the formation of MP-DOM derived disinfection byproducts during chlorination disinfection were first investigated. Comparably, PS-MPs are more vulnerable to chlorination and the primary attacks are on para C in aromatic side-chains via electrophilic Cl-substitution and oxidation by two-electron transfer. The O/C and Cl/C ratio of polystyrene MPs was linear and exponential versus initial available Cl2 concentrations, respectively. The significant PS-DOM leaching was observed with initial available Cl2 of 4.0 mg/L (USEPA recommended upper dose). As the initial available Cl2 concentration increased to 8.0 mg/L, the adsorption of chloro-phenolic-components of 200 Daltons in PS-DOM by 5 µm PS-MPs was observed for the first time. Trichloromethane (TCM) was identified as the dominant disinfection byproduct with a formation potential of 60.3 ± 7.8 and 73.7 ± 9.8 μg/mg for PS-DOM and PP-DOM, respectively. The derived TCM could adsorb onto PS-MPs followed the pseudo-second-order kinetic and Langmuir isotherm models. Extreme chlorination could reduce the maximal adsorption capacity of TCM on 5 µm PS-MPs from 196.68 ± 48.66 to 146.02 ± 32.98 μg/g. Thus, PS-MPs act as precursors and carriers of TCM in chlorination.

Atmospheric microplastic deposition in a coastal city of India: The influence of a landfill source on monsoon winds

Coastal zones experience various wind events that may influence the characteristics, distribution, and dynamics of atmospheric microplastic pollutants. In the present study, we investigated the characteristics of the bulk atmospheric microplastic deposition in Kochi, Kerala, India, during three distinct seasons: Northeast Monsoon (NEM), Summer (SMR), and Southwest monsoon (SWM). Seasonally, the highest microplastic fallout rate was recorded for the NEM (37.29 particles m-2d-1), followed by SMR (15.17 particles m-2 d-1) and the SWM (11.57 particles m-2d-1). The microplastic abundance was not correlated to the amount of rainfall. Further, the wind rose and HYSPLIT trajectory analysis illustrated the arrival of northeast monsoon winds to the city via the region in and around the municipal landfill, which could be a major source of airborne microplastic to the sampling stations, and the forward trajectories from the landfill site extended into the Arabia Sea, providing evidence on the potential atmospheric transport and subsequent deposition of microplastics into the ocean. With respect to the qualitative characteristics, blue-coloured and fibrous microplastics dominated the samples with a considerable number of particles belonging to the size range of 200-500 μm. The practice of drying synthetic clothes under natural sunlight may have substantially contributed to the increased prevalence of airborne microfibers. The higher numbers of polyethylene (PE) and polypropylene (PP) in the bulk microplastic deposition reinforce the concept of low-density polymers being more susceptible to deflation by the wind. Overall, the work signifies the role of monsoon winds in transporting microplastics from an unscientifically managed municipal landfill site and also highlights the importance of reducing the quantity of plastic waste ending up at the landfill to reduce the emission of microplastics proportionately.

A mini-review on plasticrusts: occurrence, current trends, potential threats, and recommendations for coastal sustainability

Plasticrusts manifest as a coating on intertidal rocks due to environmental exposure. They refer to crushed plastic debris that blankets rocks found along intertidal shorelines. This study significantly contributes to a better understanding of the occurrence of these novel plastic formations, shedding light on their potential pathways of formation during the Anthropocene era. The research provides comprehensive insights into the composition, origins, challenges, and effective management strategies for removing coastal plastic litter. The findings of this investigation offer valuable evidence regarding the formation and impact of these recently discovered plastic items in coastal regions, prompting discussions about their formation processes and their effects on the marine ecosystem. Recognizing that these newly emerged plastic litter pose a considerable threat to the marine environment is crucial. With their emergence, we face an environmental challenge, especially concerning the health of coastal ecosystems. Plasticrusts, when degraded, can release microplastics (MPs) and nanoparticles (NPs) into the surrounding environment. These micro- and nano-sized plastic particles pose significant ecological risks as they persist in ecosystems, potentially harming wildlife and entering the food chain, causing widespread environmental contamination. Significantly, it outlines strategies to minimize the impact of this emerging plastic debris and its source.

Polystyrene nanoparticles induced mammalian intestine damage caused by blockage of BNIP3/NIX-mediated mitophagy and gut microbiota alteration

Nanoplastics possess the capacity for cellular internalization, and consequentially disrupt mitochondrial functionality, precipitating aberrations in energy metabolism. Given this, the potential accumulation of nanoplastics in alimentary sources presents a considerable hazard to the mammalian gastrointestinal system. While mitophagy serves as a cytoprotective mechanism that sustains redox homeostasis through the targeted removal of compromised mitochondria, the regulatory implications of mitophagy in nanoplastic-induced toxicity remain an underexplored domain. In the present investigation, polystyrene (PS) nanoparticles, with a diameter of 80 nm employed as a representative model to assess their toxicological impact and propensity to instigate mitophagy in intestinal cells both in vitro and in vivo. Data indicated that PS nanoparticles elicited BNIP3/NIX-mediated mitophagy within the intestinal milieu. Strikingly, the impediment of this degradation process at elevated concentrations was correlated with exacerbated pathological ramifications. In vitro assays corroborated that high-dosage cellular uptake of PS nanoparticles obstructed the mitophagy pathway. Furthermore, treatment with PS nanoparticles engendered alterations in gut microbiota composition and manifested a proclivity to modulate nutritional metabolism. Collectively, these findings elucidate that oral exposure to PS nanoparticles culminates in the inhibition of mitophagy and induces perturbations in the intestinal microbiota. This contributes valuable insights into the toxicological repercussions of nanoplastics on mammalian gastrointestinal health.

Polyethylene Terephthalate Hydrolases in Human Gut Microbiota and Their Implications for Human Health

Polyethylene terephthalate (PET), primarily utilized for food and beverage packaging, consistently finds its way into the human gut, thereby exerting adverse effects on human health. PET hydrolases, critical for the degradation of PET, have been predominantly sourced from environmental microbial communities. Given the fact that the human gut harbors a vast and intricate consortium of microorganisms, inquiry into the presence of potential PET hydrolases within the human gut microbiota becomes imperative. In this investigation, we meticulously screened 22,156 homologous sequences that could potentially encode PET hydrolases using the hidden Markov model (HMM) paradigm, drawing from 4984 cultivated genomes of healthy human gut bacteria. Subsequently, we methodically validated the hydrolytic efficacy of five selected candidate PET hydrolases on both PET films and powders composed of micro-plastics (MPs). Notably, our study also unveiled the influence of both diverse PET MP powders and their resultant hydrolysates on the modulation of cytokine expression in macrophages. In summary, our research underscores the ubiquitous prevalence and considerable potential of the human gut microbiota in PET hydrolysis. Furthermore, our study significantly contributes to the holistic evaluation of the potential health hazards posed by PET MPs to human well-being.

Atmospheric microfibrous deposition over the Eastern Red Sea coast

The transport of microplastics through the atmosphere has been acknowledged as a significant route for their dispersion across different environments. Microplastics of fibrous shape often prevail in environmental samples, although their composition identification might be challenging and lead to an overestimation of plastic microfibers (MFs). Conversely, MFs of natural origin are rarely reported in microplastics studies despite the lack of consensus on the risks they may pose to the environment. In this study, airborne MFs collected in a sparsely populated residential area on the shore of the Eastern Red Sea were analyzed to investigate their abundance and polymer composition and assess their potential transport and deposition rates. The length of observed fibers ranged from 183 μm to 11,877 μm, with 3 % of fibers being >5 mm. The average length of MFs (< 5 mm) was 1378 ± 934 μm. Plastic MFs comprised 10 % of all identified MFs, with polyester being the most common plastic polymer (81.25 %). The mean abundance of airborne MFs was 0.9 ± 0.8 × 10-2 MFs m-3. The estimated mean atmospheric microfibrous deposition was 70 MFs m-2 d-1, with a component of 8 plastic MFs m-2 d-1. Based on the HYSPLIT backward trajectory analysis, fibers of local origin (estimated to travel approximately 25 km before sampling) were deposited at the sampling location. Air masses of northwestern origin traveling along the coast of the Eastern Red Sea dominated, potentially reducing the abundance of airborne MFs.

Emerging Contaminants: An Emerging Risk Factor for Diabetes Mellitus

Emerging contaminants have been increasingly recognized as critical determinants in global public health outcomes. However, the intricate relationship between these contaminants and glucose metabolism remains to be fully elucidated. The paucity of comprehensive clinical data, coupled with the need for in-depth mechanistic investigations, underscores the urgency to decipher the precise molecular and cellular pathways through which these contaminants potentially mediate the initiation and progression of diabetes mellitus. A profound understanding of the epidemiological impact of these emerging contaminants, as well as the elucidation of the underlying mechanistic pathways, is indispensable for the formulation of evidence-based policy and preventive interventions. This review systematically aggregates contemporary findings from epidemiological investigations and delves into the mechanistic correlates that tether exposure to emerging contaminants, including endocrine disruptors, perfluorinated compounds, microplastics, and antibiotics, to glycemic dysregulation. A nuanced exploration is undertaken focusing on potential dietary sources and the consequential role of the gut microbiome in their toxic effects. This review endeavors to provide a foundational reference for future investigations into the complex interplay between emerging contaminants and diabetes mellitus.

Polystyrene microplastics induce size-dependent multi-organ damage in mice: Insights into gut microbiota and fecal metabolites

Particle size is one of the most important factors in determining the biological toxicity of microplastics (MPs). In this study, we attempted to examine the systemic toxicity of polystyrene MPs of different sizes (0.5 µm MP1 and 5 µm MP2) in C57BL/6 J mice. After the mice were given oral gavage of MPs for 8 consecutive weeks, histopathology and molecular biology assays, 16 S rRNA sequencing of the gut microbiota, and untargeted metabolomics were performed. The results showed that MPs were distributed in the organs in a size-dependent manner, with smaller particles demonstrating greater biodistribution. Further analysis indicated that exposure to MPs caused multi-organ damage through distinct toxicity pathways. Specifically, exposure to 0.5 µm MP1 led to excessive accumulation and induced more serious inflammation and mechanical damage in the spleen, kidney, heart, lung, and liver. However, 5 µm MP2 led to more severe intestinal barrier dysfunction, as well as gut dysbiosis and metabolic disorder in association with neuroinflammation. These results are helpful in expanding our knowledge of the toxicity of MPs of different sizes in mammalian models.

Superb microplastics separation performance of graphene oxide tuned by laser bombardment

Microplastics have been identified as a significant environmental threat to aquatic ecosystems and human health. Consequently, there is an urgent need for efficient separation methods for small-sized MPs. In this study, a super-hydrophilic graphene oxide (GO) membrane is successfully prepared by facilely depositing GO on a microfiltration substrate, without introducing any surface modification materials, especially nanoparticles, which may cause secondary pollution. Laser bombardment reduces GO lamellar size (23.6% of its original size) and creates an abundance of defects and undulating wrinkles, enabling the deposited GO membrane to have more and shorter pathways for water. As a result, the filtration permeance for 10 μm polyvinyl chloride reaches up to 3396 L m-2 h-1 bar-1, a 1-2-order-of-magnitude enhancement compared to the unirradiated GO membrane, and is also superior to most nanoparticle-modified GO membranes. Simultaneously, the labyrinth structure endows the membrane with a high filtration efficiency of approximately 99% for the majority of MPs. This excellent performance remains virtually unchanged after repeated use. The integration of outstanding separation effects and health safety presents opportunities for practical applications in long-term MP-in-water separation.

Identification and analysis of microplastics in human lower limb joints

Microplastics (MPs) have been detected in various human tissues, including the liver, placenta, and blood. However, studies about MPs in the human locomotor system are limited. This study evaluated the presence of MPs in the synovium of 45 patients undergoing hip or knee arthroplasty using micro-Fourier transform infrared spectroscopy, scanning electron microscopy, and Raman microscopy and investigated their association with clinical indicators and local cellular responses. A total of 343 MPs of nine common types were identified, with a mean abundance of 5.24 ± 2.07 particles/g and ranging from 1.16 to 10.77 particles/g. Although there was no clear correlation between MP abundance and demographics, MP abundance was higher in hip samples than in knee samples. In addition, a potential association was observed between MP abundance and specific clinical diagnoses. Transcriptomic analysis revealed that a three-fold increase in MP abundance corresponded to enhanced local cellular stress responses, particularly heat shock protein reactions. Our findings demonstrate the presence of MPs in human joints and suggest that further studies are needed to explore the intricate associations between MPs and anatomical location, clinical diagnosis, and local cellular responses.

Microplastics exposure: implications for human fertility, pregnancy and child health

Plastics found in our everyday environment are becoming an increasing concern for individual and population-level health, and the extent of exposure and potential toxic effects of these contaminants on numerous human organ systems are becoming clear. Microplastics (MPs), tiny plastic particles, appear to have many of the same biological effects as their plastic precursors and have the compounded effect of potential accumulation in different organs. Recently, microplastic accumulation was observed in the human placenta, raising important questions related to the biological effects of these contaminants on the health of pregnancies and offspring. These concerns are particularly heightened considering the developmental origins of health and disease (DOHaD) framework, which postulates that in utero exposure can programme the lifelong health of the offspring. The current review examines the state of knowledge on this topic and highlights important avenues for future investigation.

Emerging pollutants in etiology and pathophysiology of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a multifactorial endocrine disorder affecting reproductive-aged women worldwide. Although genetic and lifestyle factors have been implicated in its etiology, emerging evidence suggests that exposure to environmental pollutants may also contribute significantly to the development and pathophysiology of PCOS. This review article aims to provide a comprehensive overview of the potential role of emerging pollutants, including pharmaceuticals and personal care products (PPCPs), microplastics, endocrine disruptors, and nanoparticles, in PCOS development. The article summarizes the current understanding of PCOS pathogenesis and its clinical manifestations. Subsequently, it delves into the mechanisms of action of the emerging pollutants, exploring how they may disrupt the endocrine system, interfere with hormonal regulation, and contribute to the manifestation of PCOS symptoms. Moreover, the potential for cumulative effects and synergistic interactions between these pollutants demands a cautious approach when considering their role in PCOS etiology.

Analysis of microplastics in ships ballast water and its ecological risk assessment studies from the Persian Gulf

Transport of ballast water is considered a significant vector for dispersion of different pollutants, including microplastics (MPs), throughout the world's oceans. However, there is limited information on MPs in ballast water. Size distribution, polymer type, and ecological risks of MPs in ballast water were investigated for the first time in this study. The mean levels of MPs in ballast water and seawater samples were 12.53 and 11.80 items/L, respectively. MPs with a size category of 50-300 μm was the most abundant. Fiber, black, and polycarbonate (PC) were the predominant shape, color, and polymer type of identified MPs in ballast water and seawater, respectively. The pollution load index (PLI), hazard index (HI), and risk quotient (RQ) indicated high levels of MP pollution, potentially indicating an ecological risk. These findings increase our understanding of the major sources (such as ballast water), transportation routes, and related ecological risks of MPs to marine ecosystems.

Arsenic and polystyrene-nano plastics co-exposure induced testicular toxicity: Triggers oxidative stress and promotes apoptosis and inflammation in mice

Co-existing of polystyrene-nano plastics (PSNPs) and arsenic (As) in the environment caused a horrendous risk to human health. However, the potential mechanism of PSNPs and As combination induced testicular toxicity in mammals has not been elucidated. Therefore, we first explore the testicular toxicity and the potential mechanism in male Kunming mice exposed to As or/and PSNPs. Results revealed that compared to the As or PSNPs group, the combined group showed more significant testicular toxicity. Specifically, As and PSNPs combination induced irregular spermatozoa array and blood-testis barrier disruption. Simultaneously, As and PSNPs co-exposure also exacerbated oxidative stress, including increasing the MDA content, and down-regulating expression of Nrf-2, HO-1, SOD-1, and Trx. PSNPs and As combination also triggered testicular apoptosis, containing changes in apoptotic factors (P53, Bax, Bcl-2, Cytc, Caspase-8, Caspase-9, and Caspase-3). Furthermore, co-exposed to As and PSNPs aggravated inflammatory damage characterized by targeted phosphorylation of NF-κB and degradation of I-κB. In summary, our results strongly confirmed As + PSNPs co-exposure induced the synergistic toxicity of testis through excessive oxidative stress, apoptosis, and inflammation, which could offer a new sight into the mechanism of environmental pollutants co-exposure induced male reproductive toxicity.

Embryonic exposure of polystyrene nanoplastics affects cardiac development

Micro- and nanoplastics have recently been detected in human blood and placentas, indicating inevitable embryonic exposure to these particles. However, their influence on human embryogenesis and the underlying mechanisms are still unknown. In this study, the effects of polystyrene nanoplastics (PS-NPs) exposure on cardiac differentiation of human embryonic stem cells (hESCs) were evaluated. Uptake of PS-NPs not only caused cellular injury, but also regulated cardiac-related pathways as revealed by RNA-sequencing. Consequently, the efficiency of cardiomyocyte differentiation from hESCs was compromised, leading to immature of cardiomyocytes and smaller cardiac organoids with impaired contractility. Mechanistically, PS-NPs promoted mitochondrial oxidative stress, activated P38/Erk MAPK signaling pathway, blocked autophagy flux, and eventually reduced the pluripotency of hESCs. Consistently, in vivo exposure of PS-NPs from cleavage to gastrula period of zebrafish embryo led to reduced cardiac contraction and blood flow. Collectively, this study suggests that PS-NPs is a risk factor for fetal health, especially for heart development.

Endoplasmic reticulum stress exacerbates microplastics-induced toxicity in animal cells

Human and animal exposure to microplastics (MPs) contained in food is inevitable because of their widespread existence in the environment. Nevertheless, MPs toxicity studies in ruminants often lack attention. Here, we assessed the cytotoxicity of polystyrene microplastics (PS MPs) on goat mammary epithelial cells (GMECs). Compared to controls, PS MPs treatment significantly reduced cell viability, altered cell morphology and disrupted organelle integrity. Detection of membrane potential and reactive oxygen species (ROS) suggested that PS MPs induced mitochondrial dysfunction and oxidative stress. Further transcriptome analysis also confirmed alterations in these pathways. In addition, several genes related to endoplasmic reticulum (ER) homeostasis were significantly regulated in the transcriptional profile. Subsequent experiments confirmed that PS MPs induce ER stress via the PERK/eIF2α/CHOP pathway, accompanied by intracellular Ca2+ overload. Meanwhile, downstream activation of the Bax/Bcl-2 pathway and caspase cascade released apoptotic signals, which led to apoptosis in GMECs. Interestingly, the addition of PERK inhibitor (ISRIB) attenuated PS MPs-induced ER stress and apoptosis, which suggests that ER stress may exacerbate PS MPs-induced cytotoxicity. This work reveals the impact of MPs on mammalian cytotoxicity, enriches the mechanisms for the toxicity of MPs, and provides insight for further assessment of the risk of MPs in food.

Fish microplastic ingestion may induce tipping points of aquatic ecosystems

Microplastics can be ingested by a wide range of aquatic animals. Extensive studies have demonstrated that microplastic ingestion-albeit often not lethal-can affect a range of species life-history traits. However, it remains unclear how the sublethal effects of microplastics on individual levels scale up to influence ecosystem-level dynamics through cascading trophic interactions. Here we employ a well-studied, empirically fed three-species trophic chain model, which was parameterized to mimic a common type of aquatic ecosystems to examine how microplastic ingestion by fish on an intermediate trophic level can produce cascading effects on the species at both upper and lower trophic levels. We show that gradually increasing microplastics in the ingested substances of planktivorous fish may cause population structure effects such as skewed size distributions (i.e. reduced average body length vs. increased maximal body size), and induce abrupt declines in fish biomass and reproduction. Our model analysis demonstrates that these abrupt changes correspond to an ecosystem-level tipping point, crossing which difficult-to-reverse ecosystem degradation can happen. Importantly, microplastic pollution may interact with other anthropogenic stressors to reduce safe operating space of aquatic ecosystems. Our work contributes to better understanding complex effects of microplastic pollution and anticipating tipping points of aquatic ecosystems in a changing world. It also calls attention to an emerging threat that novel microplastic contaminants may lead to unexpected and abrupt degradation of aquatic ecosystems, and invites systematic studies on the ecosystem-level consequences of microplastic exposure.

The potential impacts of micro-and-nano plastics on various organ systems in humans

Humans are exposed to micro-and-nano plastics (MNPs) through various routes, but the adverse health effects of MNPs on different organ systems are not yet fully understood. This review aims to provide an overview of the potential impacts of MNPs on various organ systems and identify knowledge gaps in current research. The summarized results suggest that exposure to MNPs can lead to health effects through oxidative stress, inflammation, immune dysfunction, altered biochemical and energy metabolism, impaired cell proliferation, disrupted microbial metabolic pathways, abnormal organ development, and carcinogenicity. There is limited human data on the health effects of MNPs, despite evidence from animal and cellular studies. Most of the published research has focused on specific types of MNPs to assess their toxicity, while other types of plastic particles commonly found in the environment remain unstudied. Future studies should investigate MNPs exposure by considering realistic concentrations, dose-dependent effects, individual susceptibility, and confounding factors.

Effects of the adsorption behavior of polyamide microplastics on male reproductive health by reduction of testosterone bioavailability

Microplastics (MPs) are global environmental pollutants with potential toxicity concerns, and their effects on the reproductive system have attracted increasing attention. This study investigated the interaction between MPs and mammalian biomolecules, focusing on the relationship between the testosterone adsorption behavior of MPs and male reproductive health. The adsorption capacity of different types of MPs for testosterone was evaluated in vitro experiments. Polyamide (PA)-MPs exhibited stronger adsorption, while polymethyl methacrylate (PMMA)-MPs displayed the weakest adsorption. Sorption equilibrium between PA-MPs and testosterone was achieved within 6 h, fitting the Pseudo-2nd-order model and Langmuir isotherm. The effects of MPs on male reproduction in mice was determined in vivo experiments. Male mice were treated with 0.1 and 0.5 mg/d PA-MPs/PMMA-MPs by gavage once per day for 28 days. The results showed that only 0.5 mg/d PA-MP exposure induced decreased serum testosterone levels, increased testicular testosterone levels compared to the control, and more severe damage to seminiferous tubule structure, sperm motility and sperm morphology compared to the PMMA-MPs group. Meanwhile, PA-MPs could reduce intracellular nuclear translocation of androgen receptor (AR) mediated by testosterone, while PMMA-MPs had no impact. The study revealed that PA-MP adsorption reduced testosterone bioavailability and caused sperm quality to decline, offering new insights into the combined toxicity mechanism of MPs in male mammals.

PLASTAMINATION: Outcomes on the Central Nervous System and Reproduction

BACKGROUND

Environmental exposures to non-biodegradable and biodegradable plastics are unavoidable. Microplastics (MPs) and nanoplastics (NPs) from the manufacturing of plastics (primary sources) and the degradation of plastic waste (secondary sources) can enter the food chain directly or indirectly and, passing biological barriers, could target both the brain and the gonads. Hence, the worldwide diffusion of environmental plastic contamination (PLASTAMINATION) in daily life may represent a possible and potentially serious risk to human health.

OBJECTIVE

This review provides an overview of the effects of non-biodegradable and the more recently introduced biodegradable MPs and NPs on the brain and brain-dependent reproductive functions, summarizing the molecular mechanisms and outcomes on nervous and reproductive organs. Data from in vitro, ex vivo, non-mammalian and mammalian animal models and epidemiological studies have been reviewed and discussed.

RESULTS

MPs and NPs from non-biodegradable plastics affect organs, tissues and cells from sensitive systems such as the brain and reproductive organs. Both MPs and NPs induce oxidative stress, chronic inflammation, energy metabolism disorders, mitochondrial dysfunction and cytotoxicity, which in turn are responsible for neuroinflammation, dysregulation of synaptic functions, metabolic dysbiosis, poor gamete quality, and neuronal and reproductive toxicity. In spite of this mechanistic knowledge gained from studies of non-biodegradable plastics, relatively little is known about the adverse effects or molecular mechanisms of MPs and NPs from biodegradable plastics.

CONCLUSION

The neurological and reproductive health risks of MPs/NPs exposure warrant serious consideration, and further studies on biodegradable plastics are recommended.

Airborne microplastic/nanoplastic research: a comprehensive Web of Science (WoS) data-driven bibliometric analysis

This paper presents the landscape of research on airborne microplastics and nanoplastics (MPs/NPs) according to the bibliometric analysis of 147 documents issued between 2015 and 2021, extracted from the Web of Science database. The publications on airborne MPs/NPs have increased rapidly from 2015 onwards, which is largely due to the existence of funding support. Science of the Total Environment is one of the prominent journals in publishing related papers. China, England, the USA, and European Countries have produced a significant output of airborne MP/NP research works, which is associated with the availability of funding agencies regionally or nationally. The research hotspot on the topic ranges from the transport of airborne MPs/NPs to their deposition in the terrestrial or aquatic environments, along with the contamination of samples by indoor MPs/NPs. Most of the publications are either research or review papers related to MPs/NPs. It is crucial to share the understanding of global plastic pollution and its unfavorable effects on humankind by promoting awareness of the existence and impact of MPs/NPs. Funding agencies are vital in boosting the research development of airborne MPs/NPs. Some countries that are lacking funding support were able to publish research findings related to the field of interest, however, with lesser research output. Without sufficient fundings, some impactful publications may not be able to carry a substantial impact in sharing the findings and discoveries with the mass public.

Recent advances in surface tailoring of thin film forward osmosis membranes: A review

The recent advancements in fabricating forward osmosis (FO) membranes have shown promising results in desalination and water treatment. Different methods have been applied to improve FO performance, such as using mixed or new draw solutions, enhancing the recovery of draw solutions, membrane modification, and developing FO-hybrid systems. However, reliable methods to address the current issues, including reverse salt flux, fouling, and antibacterial activities, are still in progress. In recent decades, surface modification has been applied to different membrane processes, including FO membranes. Introducing nanochannels, bioparticles, new monomers, and hydrophilic-based materials to the surface layer of FO membranes has significantly impacted their performance and efficiency and resulted in better control over fouling and concentration polarization (CP) in these membranes. This review critically investigates the recent developments in FO membrane processes and fabrication techniques for FO surface-layer modification. In addition, this study focuses on the latest materials and structures used for the surface modification of FO membranes. Finally, the current challenges, gaps, and suggestions for future studies in this field have been discussed in detail.

Chronic exposure to polystyrene nanoplastics induces intestinal mechanical and immune barrier dysfunction in mice

Micro(nano)plastics are prevalent in the environment, and prolonged exposure to them represents a threat to human health. The goal of this study is to assess the health risk of long-term exposure to nanoplastics (NPs) at environmental concentrations on the intestinal mechanical and immune barrier in mice. In this study, mice were provided drinking water containing polystyrene NPs (PS-NPs; 0.1, 1, and 10 mg·L-1) for 32 consecutive weeks. The levels of endocytosis proteins caveolin and clathrin and of tight junctional proteins claudin-1, occludin, and ZO-1, and morphological changes, proportion of lymphocytes B in MLNs and lymphocytes T in IELs and LPLs were determined by immunohistochemistry, hematoxylin-eosin, and flow cytometry assays in the intestinal tissues of mice at 28 weeks. The activities or concentrations of ROS, SOD, MDA, and GSH-Px and inflammatory factors (IL-1β, IL-6, and TNF-α) in the intestinal tissues of mice were measured by ELISA at 12, 16, 20, 24, and 32 weeks. Compared with the control group, oral ingested PS-NPs entered the intestinal tissues of mice and upregulated expression levels of the clathrin and caveolin. The intestinal tissue structure of mice in the PS-NPs (1 and 10 mg·L-1) exposure groups showed significant abnormalities, such as villus erosion, decreased of crypts numbers and large infiltration of inflammatory cells. Exposure to 0.1 mg·L-1 PS-NPs decreased occludin protein levels, but not claudin-1 and ZO-1 levels. The levels of these three tight junction proteins decreased significantly in the 1 and 10 mg·L-1 PS-NPs exposed groups. Exposure to PS-NPs led to a significant time- and dose-dependent increase in ROS and MDA levels, and concurrently decreased GSH-Px and SOD contents. Exposure to PS-NPs increased the proportion of B cells in MLNs, and decreased the proportion of CD8+ T cells in IELs and LPLs. The levels of pro-inflammatory cytokines IL-6, TNF-α and IL-1β were markedly elevated after PS-NPs exposure. Long-term PS-NPs exposure impaired intestinal mechanical and immune barrier, and indicate a potentially significant threat to human health.

Identification and characterization of microplastics in nasal irrigation fluids: A preliminary study

KEY POINTS

Microplastics were identified in nasal irrigations Polypropylenes, which were the main component of the nozzle, were commonly identified Additional studies are needed to understand the biological relevance of microplastics in nasal irrigations.