Lifetime Accumulation of Microplastic in Children and Adults

Assessing toxicity of amorphous nanoplastics in airway- and lung epithelial cells using air-liquid interface models

BACKGROUND

Inhalation is one of the main exposure routes to nanoplastics. Knowledge of the toxicological impact of nanoplastics on the airway- and lung epithelium is limited and almost exclusively based on submerged in vitro models using spherical polystyrene (PS) particles.

METHODS

Mono-cultures and advanced (co-)cultures of human bronchial- and alveolar epithelial cells, all air-liquid interface (ALI) cultures, were exposed to nanoplastics and reference nanoparticles. Alveolar models included A549 mono-cultures and A549 cells co-cultured with endothelial cells (Ea.hy926) and macrophage-like cells (differentiated THP-1). Bronchial models included BEAS-2B cells and differentiated primary bronchial epithelial cells (PBEC). Cultures were exposed to PS, copper(II) oxide (CuO) or titanium dioxide (TiO2) nanoparticles (50 nm). Additionally, BEAS-2B cells were exposed to well-characterised, amorphous polyvinyl chloride (PVC), polypropylene (PP), or polyamide (PA) nanoplastics. Cytotoxicity and inflammation (IL-8 secretion and IL-8 transcript levels) were assessed after 24 h of exposure.

RESULTS

Cell viability remained unaffected by all exposures in all models. Unlike PS and TiO2, CuO exposure dose-dependently induced IL-8 protein secretion and mRNA levels. Although the extent of IL-8 secretion differed between models, the relative response to CuO was similar in both mono-cultures and advanced (co-)cultures. None of the environmentally relevant nanoplastics (PVC, PA or PP) impacted inflammation or cell viability in BEAS-2B ALI cultures.

CONCLUSION

Although CuO induced inflammation, PS failed to elicit an inflammatory response in any of our models. For the first time, we show that PVC, PA and PP do not induce cell death or inflammation in a BEAS-2B ALI model.

Quantifying microplastics in sediments of Jinzhou Bay, China: Characterization and ecological risk with a focus on small sizes

Small-sized microplastics (MPs) pose greater ecological toxicity due to their larger surface area, which makes them more likely to act as carriers for other pollutants and to be ingested by aquatic organisms. However, traditional visual analysis often neglects small-sized MPs and their associated ecological risk. This study utilized Laser Direct Infrared (LDIR) spectroscopy and traditional visual analysis to examine MPs in 31 sediment samples from Jinzhou Bay, a typical semi-enclosed bay located at the economic center of Dalian, China. The results showed significant heterogeneity in MP distribution, with averages of 1192 and 2361 items/kg dry weight reported by visual analysis and LDIR spectroscopy, respectively. LDIR spectroscopy identified MPs as small as 10 μm, with the majority of MPs (89.21 %) within the 10-250 μm range, and a significant proportion (46.45 %) between 10 and 50 μm among them. However, visual analysis was limited to detecting MPs >50 μm, and significant portions were identified between 50 and 100 μm (49.36 %) and 100-250 μm (31.01 %), missing a substantial fraction of smaller MPs. The predominant polymers identified were polyamide (PA), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). LDIR spectroscopy demonstrated a strong positive correlation between MP abundance and clay content, a relationship not observed with traditional visual analysis. The Potential Ecological Risk Index (PERI) indicated that over 87 % of sites posed an extremely high risk according to LDIR spectroscopy, compared to 51 % by traditional visual analysis. These discrepancy underscores the underestimation of ecological risks by traditional methods, particularly for small-sized MPs. High-risk polymers such as polyvinyl chloride (PVC), ABS, and polyurethane (PUR) significantly influenced PERI values. These findings highlight the critical need for precise identification and thorough risk assessment of small-sized MPs in environmental studies and offer insights for understanding of MP vertical migration in aquatic environments, particularly in the context of co-settlement with sediments.

Microplastics exacerbate tissue damage and promote carcinogenesis following liver infection in mice

Cancer is a leading cause of death worldwide, posing a substantial threat to human well-being. Microplastics (MPs) exposure can harm human health and the carcinogenicity of MP remains uncertain. In this study, we investigated carcinogenesis by MPs exposure. We observed MP significantly exacerbated hepatic injury in infectious conditions. In addition, cancer-related p53 and p21 signals are activated by MPs. Analysis of the liver transcriptomic landscape uncovered a noteworthy intensification of the carcinogenesis pathway by MPs compared with pre-infection. The transcription factor SALL2 could act as an oncogenic promoter in the promotion of cancer regulated by MPs. Further, big data analysis presents the correlation between MPs pollution and human hepatocellular carcinoma. This work revealed a toxic amplification effect of the non-bioactive MPs on the bioactive pathogens. This finding provides new insight into understanding the potential toxicity of the MPs.

Processes influencing the toxicity of microplastics ingested through the diet

The present study assesses the effect of culinary treatment and gastrointestinal digestion upon the release of additives present in microplastics. Organic additives were determined by gas chromatography-mass spectrometry, and inorganic additives using inductively coupled plasma-mass spectrometry. The results revealed a large number of organic additives in the plastic samples, some being classified as possible carcinogens. Contents of Sb in PET (polyethylene terephthalate), Zn and Ba in LDPE (low-density polyethylene) and PVC (polyvinylchloride), and Ti and Pb in LDPE were also noteworthy. The culinary process promotes the release and solubilization of additives into the cooking liquid, with phthalates, benzophenone, N-butylbenzenesulfonamide (NBBS) and bisphenol A being of particular concern. The solubilization of phthalates and NBBS was also observed during gastrointestinal digestion. This study demonstrates that culinary treatment and gastrointestinal digestion promote release and solubilization of additives from plastics ingested with the diet. Such solubilization may facilitate their entry into the systemic circulation.

Twenty years of microplastic pollution research-what have we learned?

Twenty years after the first publication that used the term microplastic, we review current understanding, refine definitions, and consider future prospects. Microplastics arise from multiple sources, including tires, textiles, cosmetics, paint, and the fragmentation of larger items. They are widely distributed throughout the natural environment, with evidence of harm at multiple levels of biological organization. They are pervasive in food and drink and have been detected throughout the human body, with emerging evidence of negative effects. Environmental contamination could double by 2040, and wide-scale harm has been predicted. Public concern is increasing, and diverse measures to address microplastic pollution are being considered in international negotiations. Clear evidence on the efficacy of potential solutions is now needed to address the issue and to minimize the risks of unintended consequences.

A systematic review and quality assessment of estimated daily intake of microplastics through food

Plastic waste enters the oceans and soil and is consumed by organisms and humans. Some of the ingested microplastics may remain in the human body and cause toxicity. We conducted a systematic review to estimate the extent to which humans are exposed to microplastics through consumption and performed a quality assessment of research results. We searched for studies published up to December 2023 and included studies that reported on the characteristics and estimated intake of microplastics. The quality assessment tool reported in previous studies was used for food and drinking water studies. We included 76 studies in the analysis, and the types of foods were classified into seven categories: seafood, drinking water, table salt, fruits and vegetables, beverages, condiments, and meat. The estimated daily intake of microplastics via food was 0.0002-1,531,524 MP/day, with the highest value in bottled water. The quality of food and drinking water studies was evaluated using a quantitative tool to assess reliability. The quality of food studies was 11.50 out of 20 points and the quality of drinking water studies was 11.16 out of 19 points. These results indicate that the closer the score is to the maximum, the more reliable the research findings. The quantitative assessment can be used as an indicator for evaluating the risks of microplastics and can help reduce biases that may occur during the research process. This study confirmed microplastics in foods and human exposure to up to one million microplastics daily. Our study emphasizes the potential for microplastic exposure through food intake and subsequent accumulation in the human body; therefore, efforts are needed to reduce exposure to microplastics in daily life.

Bioaccumulation Rate of Non-Biodegradable Polystyrene Microplastics in Human Epithelial Cell Lines

Environment plastic accumulation has been attracting the attention of both political and scientific communities, who wish to reduce global pollution. Plastic items have been detected everywhere, from oceans to the air, raising concerns about the fate of plastics within organisms. Leaked plastics are ingested by animals, entering the food chain and eventually reaching humans. Although a lot of studies focused on the evaluation of plastic particles in the environment and living organisms have already been published, the behavior of plastic at the cellular level is still missing. Here, we analyzed the bioaccumulation and extrusion trend of two differently sized plastic particles (1 and 2 µm), testing them on three human epithelial cell lines (liver, lung, and gut) that represent epithelial sites mainly exposed to plastic. A different behavior was detected, and the major plastic uptake was shown by liver cells, where the 1 µm beads accumulated with a dose-dependent profile. Moreover, a 60% reduction in the content of 1 µm particles in cells was evaluated after plastic removal. Finally, the viability and proliferation of the three human cell lines were not significantly affected by both the 1 and 2 µm beads, suggesting that cells might have a defense mechanism against plastic exposure risk.

Microplastic exposure linked to accelerated aging and impaired adipogenesis in fat cells

Our research explores the detrimental effects of microplastic (MP) exposure on adipose tissue aging and function, emphasizing the potential health risks associated with environmental pollutants. Utilizing both in vivo and in vitro models, we discovered that MPs accumulate in adipose tissues, leading to cellular senescence, inflammation, and hindered adipogenic differentiation. Notably, our findings demonstrate that MPs prompt an aging response in both epididymal and inguinal white adipose tissue, increase senescence-associated β-galactosidase activity, and upregulate key senescence and inflammatory markers. Furthermore, we show that MPs disrupt normal adipogenic differentiation by reducing lipid droplet formation and downregulating critical adipogenic markers. These insights highlight the urgent need for further investigation into the long-term consequences of MP pollution on biological aging and underscore the importance of developing public health strategies to mitigate these effects.

Microplastics in the human body: A comprehensive review of exposure, distribution, migration mechanisms, and toxicity

Microplastics (MPs) are pervasive across ecosystems, presenting substantial risks to human health. Developing a comprehensive review of MPs is crucial due to the growing evidence of their widespread presence and potential harmful effects. Despite the growth in research, considerable uncertainties persist regarding their transport dynamics, prevalence, toxicological impacts, and the potential long-term health effects they may cause. This review thoroughly evaluates recent advancements in research on MPs and their implications for human health, including estimations of human exposure through ingestion, inhalation, and skin contact. It also quantifies the distribution and accumulation of MPs in various organs and tissues. The review discusses the mechanisms enabling MPs to cross biological barriers and the role of particle size in their translocation. To ensure methodological rigor, this review adheres to the PRISMA guidelines, explicitly detailing the literature search strategy, inclusion criteria, and the quality assessment of selected studies. The review concludes that MPs pose significant toxicological risks, identifies critical gaps in current knowledge, and recommends future research directions to elucidate the prolonged effects of MPs on human health. This work aims to offer a scientific framework for mitigating MP-related hazards and establishes a foundation for ongoing investigation.

Micro-nanoplastics and cardiovascular diseases: evidence and perspectives

Emerging evidence indicates that chemical exposures in the environment are overlooked drivers of cardiovascular diseases (CVD). Recent evidence suggests that micro- and nanoplastic (MNP) particles derived largely from the chemical or mechanical degradation of plastics might represent a novel CVD risk factor. Experimental data in preclinical models suggest that MNPs can foster oxidative stress, platelet aggregation, cell senescence, and inflammatory responses in endothelial and immune cells while promoting a range of cardiovascular and metabolic alterations that can lead to disease and premature death. In humans, MNPs derived from various plastics, including polyethylene and polyvinylchloride, have been detected in atherosclerotic plaques and other cardiovascular tissues, including pericardia, epicardial adipose tissues, pericardial adipose tissues, myocardia, and left atrial appendages. MNPs have measurable levels within thrombi and seem to accumulate preferentially within areas of vascular lesions. Their presence within carotid plaques is associated with subsequent increased incidence of cardiovascular events. To further investigate the possible causal role of MNPs in CVD, future studies should focus on large, prospective cohorts assessing the exposure of individuals to plastic-related pollution, the possible routes of absorption, the existence of a putative safety limit, the correspondence between exposure and accumulation in tissues, the timing between accumulation and CVD development, and the pathophysiological mechanisms instigated by pertinent concentrations of MNPs. Data from such studies would allow the design of preventive, or even therapeutic, strategies. Meanwhile, existing evidence suggests that reducing plastic production and use will produce benefits for the environment and for human health. This goal could be achieved through the UN Global Plastics Treaty that is currently in negotiation.

Contrasting the distribution kinetics of microplastics and nanoplastics in medaka following exposure and depuration

Direct ingestion of micro/nanoplastics (MNPs) results in significant accumulation in gastrointestinal (GI) tract of fish. The breathing process of fish makes MNPs easily retained in their gills. However, the uptake of MNPs in other fish organs remains largely unknown, let alone their kinetic processes. Herein, microplastics (MPs) and nanoplastics (NPs) in vivo imaging and precise quantification in various tissues (GI tract, gill, liver, brain, eye, and skin) of seawater (SW)- and freshwater (FW)- acclimated medaka Oryzias melastigma were achieved at an environmentally relevant concentration. Subsequently, the distribution kinetics of MNPs was investigated over a 96-h uptake and 48-h depuration period. MNPs were quickly and mostly captured in GI tract and gill of O. melastigma, and then transferred to liver and brain likely via blood circulation. Such transport was more efficient for NPs as compared to MPs, as evidenced by the consistently higher bioconcentration factors in both SW and FW conditions. The detection of MNPs in eye and skin of O. melastigma was more of an adsorption process, although the specific mechanisms of adsorption and absorption process can hardly be clearly differentiated. This study presented distribution kinetics of MNPs in O. melastigma and highlighted their possible transportation among tissues.

Wet oxidation technology can significantly reduce both microplastics and nanoplastics

For the resource recovery of biomass waste, it is a challenge to simultaneously remove micro-/nano-plastics pollution but preserve organic resources. Wet oxidation is a promising technology for valorization of organic wastes through thermal hydrolysis and oxidation. This might in turn result in the degradation of microplastics in the presence of oxygen and high temperatures. Based on this hypothesis, this study quantified both microplastics and nanoplastics in an industrial-scale wet oxidation reactor from a full-size coverage perspective. Wet oxidation significantly reduced the size and mass of individual microplastics, and decreased total mass concentration of microplastics and nanoplastics by 94.8 % to 98.6 %. This technology also reduced the micro- and nanoplastic shapes and polymer types, resulting in a complete removal of fibers, clusters, polypropylene (PP) and poly(methyl methacrylate) (PMMA). The present study confirms that wet oxidation technology is effective in removing microplastics and nanoplastics while recovering organic waste.

What if you eat nanoplastics? Simulating nanoplastics fate during gastrointestinal digestion

Despite our growing awareness of micro-and nanoplastics presence in food and beverages, the fate of nanoplastics (NPs) in the human gastrointestinal tract (GIT) remains poorly investigated. Changes of nanoplastics size upon digestive conditions influence the potential of absorption through the intestine. In this study, polymer nanoparticles with different physicochemical properties (size, surface and chemistry) were submitted to gastrointestinal digestion (GID) simulated in vitro. Their agglomeration behaviour was measured with a unique set of analytical approaches, allowing to study NPs' interactions with the digestive enzymes. Smaller NPs agglomerated more, narrowing the overall particle size distribution of smaller and larger NPs. NPs of different polymers exhibited heteroagglomeration. Digestive enzymes interact with the NPs, forming large but fragile agglomerates. In presence of the enzymes, even acid-functionalized NPs, typically stable in harsh conditions, agglomerated similarly to the non-functionalized PS NPs. These results highlight the role of the GID in increasing the effective size of ingested NPs, potentially reducing their ability to pass through the cell membranes. Our findings address a critical knowledge gap in nanoplastics oral uptake potential, providing a solid technical foundation for their characterization.

Polystyrene nanoplastics induced learning and memory impairments in mice by damaging the glymphatic system

The excessive usage of nanoplastics (NPs) has posed a serious threat to the ecological environment and human health, which can enter the brain and then result in neurotoxicity. However, research on the neurotoxic effects of NPs based on different exposure routes and modifications of functional groups is lacking. In this study, the neurotoxicity induced by NPs was studied using polystyrene nanoplastics (PS-NPs) of different modifications (PS, PS-COOH, and PS-NH2). It was found that PS-NH2 through intranasal administration (INA) exposure route exhibited the greatest accumulation in the mice brain after exposure for 7 days. After the mice were exposed to PS-NH2 by INA means for 28 days, the exploratory ability and spatial learning ability were obviously damaged in a dose-dependent manner. Further analysis indicated that these damages induced by PS-NH2 were closely related to the decreased ability of glymphatic system to clear β-amyloid (Aβ) and phosphorylated Tau (P-Tau) proteins, which was ascribed to the loss of aquaporin-4 (AQP4) polarization in the astrocytic endfeet. Moreover, the loss of AQP4 polarization might be regulated by the NF-κB pathway. Our current study establishes the connection between the neurotoxicity induced by PS-NPs and the glymphatic system dysfunction for the first time, which will contribute to future research on the neurotoxicity of NPs.

Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China

BACKGROUND

Microplastics are environmental pollutants detected in various human organs and tissues. These particles originate from multiple sources including the degradation of larger plastic items and the intentional inclusion in consumer goods. Potential risks for human health resulting from microplastics exposure have also been reported. However, the distribution in the male reproductive system and its effect remains largely unknown. This study aims to investigate the presence of multiple microplastics in human semen and urine and their association with sperm quality in a multi-site study across China.

METHODS

We conducted a cross-sectional study involving 113 male participants from three regions in China. Semen and urine samples were collected and analysed using Raman microscopy to detect eight types of microplastics: polystyrene (PS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). Semen quality parameters, including total sperm count, concentration, motility, and morphology, were assessed. Statistical analyses, including single and multi-variable models, were used to evaluate the relationship between microplastic exposure and semen quality, with a focus on PTFE, after adjusting confounding factors of age, body mass index (BMI), smoking, alcohol drinking, and sites.

FINDINGS

Microplastics were detected in all semen and urine samples, with participants typically exposed to 3-5 different types. The detection rates of PS, PP and PE were the highest. Notably, PTFE exposure was significantly associated with decreased semen quality. Participants exposed to PTFE showed reductions in total sperm count [188.90 ± 163.71 vs. 207.67 ± 132.36 million, p = 0.091], sperm concentration [52.13 ± 47.47 vs. 58.32 ± 37.26 million/mL, p = 0.041], and progressive motility [40.29% ± 19.06 vs. 34.11% ± 17.02, p = 0.083]. The multi-linear regression analysis indicated that each additional type of microplastic exposure was associated with a significant decrease in total sperm number [β = -15.4 (95% CI: -25.6, -5.2)], sperm concentration [β = -7.2 (95% CI: -12.4, -2.0)], and progressive motility [β = -8.3 (95% CI: -13.5, -3.1)]. Latent category analysis further refined these groups by types of microplastic exposure, highlighting specific types more strongly associated with decreased semen quality (OR = 3.5, 95% CI: 1.8, 6.9, p < 0.001). The nomogram can be used to assess the risk of sperm damage by combining the type of microplastic exposure in urine with age and BMI.

INTERPRETATION

Our findings highlight the potential reproductive health risks posed by microplastic contamination, particularly PTFE, a non-stick pan coating material, and raise concerns about the potential of urine testing as an indicator of male reproductive microplastic exposure. Future research is warranted to further elucidate the mechanisms underlying the adverse effects of microplastics on male fertility and cross-generational effects.

FUNDING

This study was funded by the Clinical Research Project of Shanghai Municipal Commission of Health and Family planning (20224Y0085), Open Fund Project of Guangdong Academy of Medical Sciences (YKY-KF202202), CAMS Innovation Fund for Medical Sciences (2019-I2M-5-064), Shanghai Clinical Research Center for Gynecological Diseases (22MC1940200), Shanghai Urogenital System Diseases Research Centre (2022ZZ01012), Key Discipline Construction Project (2023-2025) of Three-Year Initiative Plan for Strengthening Public Health System Construction in Shanghai (GWVI-11.1-35, GWVI-11.2-YQ29) and Shanghai Frontiers Science Research Base of Reproduction and Development.

Smartphone microscopic method for imaging and quantification of microplastics in drinking water

Analysis of microplastics in drinking water is often challenging due to smaller particle size and low particle count. In this study, we used a low cost and an easy to assemble smartphone microscopic system for imaging and quantitating microplastic particles as small as 20 μm. The system consisted of a spherical sapphire ball lens of 4 mm diameter attached to a smartphone camera as a major imaging component. It also involved pre-concentration of the sample using ZnCl2 solution. The spike recovery and limit of detection of the method in filtered distilled and deionized water samples (n = 9) were 55.6% ± 9.7% and 34 particles/L, respectively. Imaging performance of the microscopic system was similar to a commercial bright field microscopic system. The method was further implemented to examine microplastic particles in commercial bottled and jar water samples (n = 20). The particles count in bottled and jar water samples ranged from 0-91 particles/L to 0-130 particles/L, respectively. In both sample types, particles of diverse shape and size were observed. The particles collected from water samples were further confirmed by FTIR spectra (n = 36), which found 97% of the particles tested were made of plastic material. These findings suggested that the smartphone microscopic system can be implemented as a low-cost alternative for preliminary screening of microplastic in drinking water samples. RESEARCH HIGHLIGHTS: Ball lens based smartphone microscopic method was used for microplastic analysis. Particles of diverse shape and size were found in bottle and jar water samples.

Occurrence, characteristics, and risk assessment of microplastics and polycyclic aromatic hydrocarbons associated with microplastics in surface water and sediments of the Konya Closed Basin, Turkey

The presence of polycyclic hydrocarbons (PAHs) and microplastics (MPs) in aquatic environments affects the ecosystems and threatens human health. In this study, the abundance, composition, and morphological characteristics of MPs were determined for the first time in the inland freshwater resources of the Konya Closed Basin, Turkey. The abundance of MPs ranged from 1139 to 23,444 particles/m3 and 150 to 3510 particles/kg in the surface water and sediment, respectively. Fragments and fibers were the most abundant MP shapes in the surface waters (51%, 34%) and sediments (29%, 40%), followed by films, pellets, and foams. Transparent and white MPs were present at the highest percentage in surface waters (72%) and sediments (69%), followed by blue, grey, black, brown, and green. In addition, polyethylene, polypropylene, and cellophane were identified as the main polymers in surface waters (34%, 25%, 24%) and sediments (37%, 17%, 31%). In the Konya Closed Basin, 35% of the surface water samples and 54% of the sediment samples were exposed to very high contamination (CF ≥ 6). Surface waters (PLI: 2.51) and sediments (PLI: 1.67) in the basin were contaminated (PLI > 1) with MPs. The 16 PAHs sorbed on MPs in the surface water and sediment ranged from 394 to 24,754 ng/g and from 37 to 18,323 ng/g, respectively. Phenanthrene and fluoranthene were the most abundant PAHs sorbed on MPs in all surface waters and sediments. Two to three-ring PAH compounds sorbed on MPs were also dominantly detected in surface waters and sediments, accounting for 68% and 78% of the total 16 PAHs, respectively. The source of PAHs carried by MPs in the Konya Closed Basin was mainly of petrogenic origin. Incremental lifetime cancer risk (ILCR) results indicated that the maximum ILCR values were higher than the EPA acceptable level (10-6) for child (2.95 × 10-5) and adult (1.46 × 10-4), indicating a potential cancer risk.

Addressing the relevance of polystyrene nano- and microplastic particles used to support exposure, toxicity and risk assessment: implications and recommendations

BACKGROUND

There has been an exponential increase in the number of studies reporting on the toxicological effects associated with exposure to nano and microplastic particles (NMPs). The majority of these studies, however, have used monodispersed polystyrene microspheres (PSMs) as 'model' particles. Here we review the differences between the manufacture and resulting physicochemical properties of polystyrene used in commerce and the PSMs most commonly used in toxicity studies.

MAIN BODY

In general, we demonstrate that significant complexity exists as to the properties of polystyrene particles. Differences in chemical composition, size, shape, surface functionalities and other aspects raise doubt as to whether PSMs are fit-for-purpose for the study of potential adverse effects of naturally occurring NMPs. A realistic assessment of potential health implications of the exposure to environmental NMPs requires better characterisation of the particles, a robust mechanistic understanding of their interactions and effects in biological systems as well as standardised protocols to generate relevant model particles. It is proposed that multidisciplinary engagement is necessary for the development of a timely and effective strategy towards this end. We suggest a holistic framework, which must be supported by a multidisciplinary group of experts to work towards either providing access to a suite of environmentally relevant NMPs and/or developing guidance with respect to best practices that can be adopted by research groups to generate and reliably use NMPs. It is emphasized that there is a need for this group to agree to a consensus regarding what might best represent a model NMP that is consistent with environmental exposure for human health, and which can be used to support a variety of ongoing research needs, including those associated with exposure and hazard assessment, mechanistic toxicity studies, toxicokinetics and guidance regarding the prioritization of plastic and NMPs that likely represent the greatest risk to human health. It is important to acknowledge, however, that establishing a multidisciplinary group, or an expert community of practice, represents a non-trivial recommendation, and will require significant resources in terms of expertise and funding.

CONCLUSION

There is currently an opportunity to bring together a multidisciplinary group of experts, including polymer chemists, material scientists, mechanical engineers, exposure and life-cycle assessment scientists, toxicologists, microbiologists and analytical chemists, to provide leadership and guidance regarding a consensus on defining what best represents environmentally relevant NMPs. We suggest that given the various complex issues surrounding the environmental and human health implications that exposure to NMPs represents, that a multidisciplinary group of experts are thus critical towards helping to progress the harmonization and standardization of methods.

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

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

Adverse health effects of exposure to plastic, microplastics and their additives: environmental, legal and policy implications for Israel

BACKGROUND

Israel is a regional "hotspot" of plastic pollution, with little discussion of potential adverse health effects from exposure to plastic. This review aims to stimulate discussion and drive policy by focusing on these adverse health effects.

MAIN BODY

Plastics are synthetic polymers containing additives which can leach from food- and beverage-contact plastic into our food and beverages, and from plastic textiles onto our skin. Plastics persist in the environment for generations, fragmenting into MNPs: Micro (1 micron-5 mm)-Nano (1 nm-1 micron)-Plastic, which contaminate our atmosphere, water, and food chain. MNP can enter the human body through ingestion, inhalation and touch. MNP < 10 microns can cross epithelial barriers in the respiratory and gastrointestinal systems, and fragments < 100 nm can cross intact skin, enabling entry into body tissues. MNP have been found in multiple organs of the human body. Patients with MNP in atheromas of carotid arteries have increased risk of a combined measure of stroke, cardiovascular disease, and death. Toxic additives to plastics include bisphenols, phthalates, and PFAS, endocrine-disrupting chemicals (EDCs) which cause dysregulation of thyroid function, reproduction, and metabolism, including increased risk of obesity, diabetes, endometriosis, cancer, and decreased fertility, sperm count and quality. Fetal exposure to EDCs is associated with increased rates of miscarriages, prematurity and low birth weight. There is likely no safe level of exposure to EDCs, with increasing evidence of trans-generational and epigenetic effects. There are several existing Israeli laws to reduce plastic use and waste. Taxes on single-use plastic (SUP) were recently cancelled. There are many gaps in regulatory standards for food-, beverage- and child- safe plastic. Existing standards are poorly enforced.

CONCLUSION

Reduction in production and use of plastic, promotion of recycling and reduction of leaching of toxic additives into our food and beverages are essential policy goals. Specific recommendations: Periodic monitoring of MNP in bottled beverages, food, indoor air; Strengthen enforcement of standards for food-, beverage-, and child-safe plastic; Renew tax on SUPs; National ban on SUP at public beaches, nature reserves and parks; Ban products manufactured with MNP; Increase research on sources and health outcomes of exposure to MNP and EDCs.

Ingestion of polyethylene terephthalate microplastic water contaminants by Xenopus laevis tadpoles negatively affects their resistance to ranavirus infection and antiviral immunity

Small plastic debris (0.1 μm-5 mm) or microplastics (MPs) have become major pollutants of aquatic ecosystems worldwide and studies suggest that MPs exposure can pose serious threats to human and wildlife health. However, to date the potential biological impacts of MPs accumulating in low amount in tissues during early life remains unclear. Here, for a more realistic assessment, we have used environmentally representative, mildly weathered, polyethylene terephthalate microplastics (PET MPs), cryomilled (1-100 μm) and fluorescently labelled. We leveraged the amphibian Xenopus laevis tadpoles as an animal model to define the biodistribution of PET MPs and determine whether exposure to PET MPs induce perturbations of antiviral immunity. Exposure to PET MPs for 1-14 days resulted in detectable PET MPs biodistribution in intestine, gills, liver, and kidney as determined by fluorescence microscopy on whole mount tissues. PET MPs accumulation rate in tissues was further evaluated via a novel in situ enzymatic digestion and subsequent filtration using silicon nanomembranes, which shows that PET MPs rapidly accumulate in tadpole intestine, liver and kidneys and persist over a week. Longer exposure (1 month) of tadpoles to relatively low concentration of PET MPs (25 μg/ml) significantly increased susceptibility to viral infection and altered innate antiviral immunity without inducing overt inflammation. This study provides evidence that exposure to MPs negatively impact immune defenses of aquatic vertebrates.

Fatty-acid incorporation improves hydrophobicity of pea protein based films towards better oxygen/water barrier properties and fruit protecting ability

The current study was undertaken to synthesize pea protein based films containing fatty acids with various chain lengths. Films namely PFAF1, PFAF2, and PFAF3 were fabricated in the presence of pelargonic acid, margaric acid, and pentacosanoic acid, respectively. Also, negative (PF: film formulated using protein alone) and positive control (PCF: film formulated using mixture of protein and chitosan) control were prepared. Interactions occurring within films were clarified by FTIR. Moreover, morphology and thermal behavior of samples were evaluated by SEM and TGA. Variations in thickness (PF: 0.03 mm, PFAF1: 0.03 mm, PFAF2: 0.04 mm, PFAF3: 0.04 mm, PCF: 0.06 mm) and water content (PF: 28.85 %, PFAF1: 16.20 %, PFAF2: 14.51 %, PFAF3: 12.04 %, PCF: 13.83) were obvious. Superior opacity was identified in PCF, followed by PFAF3, PFAF2, PFAF1, and PF. PFAF3 together with PCF were more successful than others in reducing/protecting oxygen and water permeation. Adding fatty acid or chitosan to protein films led to the decline in tensile strength (TS) and increment in elongation at break (E). As for preservation performances, maximum limitations against shifts in weight and color of bananas during 7-day storage were provided by PFAF3. Also, except for PF, all coatings (especially PFAF3) postponed the rotting of fruits.

Human intake assessment of triclosan associated with the daily use of polypropylene-made antimicrobial food packaging

In this work, we aimed to evaluate human intake of triclosan (TCS) associated with real-life use of different brands of Microban™ microwave-safe food packaging. Calculations were based on: TCS migration data (under the worst-case foreseeable conditions), MPs abundance and TCS bioaccessibility from microplastics (MPs), leached from containers under microwave heating. Bioaccessibility studies were performed with in vitro digestion of MPs, followed by liquid-liquid extraction of TCS from digestive fluids and LC-QqQ-MS analysis yielding values of 46 ± 9%. The estimated weekly intake (EWI) of TCS ranged between 11 and 42 μg/kg body weight/week, with migration being the largest contribution (0.6-2.3 mg/week), compared to leaching of MPs (75-300 μg/week). These values represent a significant source of human exposure to TCS, emphasizing the need to harmonize the ban of TCS in food contact materials worldwide and improve compliance testing of food contact articles, particularly those marketed through online sales platforms.

Seaweeds as a major source of dietary microplastics exposure in East Asia

Microplastics (MPs) occurrence in marine ecosystems is well known, but their accumulation in seaweeds and subsequent human exposure remain understudied. This research quantifies MPs presence in two commonly consumed seaweeds, kelp (Saccharina japonica) and nori (Pyropia yezoensis), in East Asia, revealing widespread contamination dominated by microfibers (<500 μm). Based on dietary patterns, human uptake through seaweed consumption was estimated and quantified. Notably, Chinese people consume an estimated 17,034 MPs/person/year through seaweed consumption, representing 13.1% of their total annual MPs intake. This seaweeds-derived exposure surpasses all other dietary sources, contributing up to 45.5% of overall MPs intake. The highest intake was in South Korea, followed by North Korea, China, and Japan. This research identifies seaweeds as a major, previously overlooked route of dietary MPs exposure. These findings are crucial for comprehensive risk assessments of seaweed consumption and the development of mitigation strategies, particularly for populations in East Asian countries.

Catalytic Upcycling of Polyolefins

The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values and multitude of short-term uses, have resulted in a significant and pressing waste management challenge. Only a small fraction of these polyolefins is currently mechanically recycled, with the rest being incinerated, accumulating in landfills, or leaking into the natural environment. Since polyolefins are energy-rich materials, there is considerable interest in recouping some of their chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy is catalytic depolymerization, in which a portion of the C-C bonds in the polyolefin backbone is broken with the assistance of a catalyst and, in some cases, additional small molecule reagents. When the products are small molecules or materials with higher value in their own right, or as chemical feedstocks, the process is called upcycling. This review summarizes recent progress for four major catalytic upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, and selective oxidation. Key considerations include macromolecular reaction mechanisms relative to small molecule mechanisms, catalyst design for macromolecular transformations, and the effect of process conditions on product selectivity. Metrics for describing polyolefin upcycling are critically evaluated, and an outlook for future advances is described.

Microplastics are associated with elevated atherosclerotic risk and increased vascular complexity in acute coronary syndrome patients

BACKGROUND

Microplastics, widely present in the environment, are implicated in disease pathogenesis through oxidative stress and immune modulation. Prevailing research, primarily based on animal and cell studies, falls short in elucidating microplastics' impact on human cardiovascular health. This cross-sectional study detected blood microplastic concentrations in patients presenting with chest pain using pyrolysis-gas chromatography/mass spectrometry and evaluating inflammatory and immune markers through flow cytometry, to explore the potential effects of microplastic on acute coronary syndrome.

RESULTS

The study included 101 participants, comprising 19 controls and 82 acute coronary syndrome cases. Notably, acute coronary syndrome patients exhibited elevated microplastic concentrations, with those suffering from acute myocardial infarction presenting higher loads compared to those with unstable angina. Furthermore, patients at intermediate to high risk of coronary artery disease displayed significantly higher microplastic accumulations than their low-risk counterparts. A significant relationship was observed between increased microplastic levels and enhanced IL-6 and IL-12p70 contents, alongside elevated B lymphocyte and natural killer cell counts.

CONCLUSION

These results suggest an association between microplastics and both vascular pathology complexity and immunoinflammatory response in acute coronary syndrome, underscoring the critical need for targeted research to delineate the mechanisms of this association.

HIGHLIGHTS

1 Blood microplastic levels escalate from angiographic patency, to angina patients, peaking in myocardial infarction patients. 2 Microplastics in acute coronary syndrome patients are predominantly PE, followed by PVC, PS, and PP. 3 Microplastics may induce immune cell-associated inflammatory responses in acute coronary syndrome patients.

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

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

Nano/micro-plastic, an invisible threat getting into the brain

Due to weather and working/operational conditions, plastic degradation produces toxic and non-biodegradable nano and microplastics (N/M-Ps, ranging from 10 nm to 5 mm), and over time these N/M-Ps have integrated with the human cycle through ingestion and inhalation. These N/M-Ps, as serious emerging pollutants, are causing considerable adverse health issues due to up-taken by the cells, tissue, and organs, including the brain. It has been proven that N/M-Ps can cross the blood-brain barrier (via olfactory and blood vessels) and affect the secretion of neuroinflammatory (cytokine and chemokine), transporters, and receptor markers. Neurotoxicity, neuroinflammation, and brain injury, which may result in such scenarios are a serious concern and may cause brain disorders. However, the related pathways and pathogenesis are not well-explored but are the focus of upcoming emerging research. Therefore, as a focus of this editorial, well-organized multidisciplinary research is required to explore associated pathways and pathogenesis, leading to brain mapping and nano-enabled therapeutics in acute and chronic N/M - Ps exposure.

Disruption of early embryonic development in mice by polymethylmethacrylate nanoplastics in an oxidative stress mechanism

Polymethylmethacrylate (PMMA) has been used in many products, such as acrylic glass, and is estimated to reach 5.7 million tons of production per year by 2028. Thus, nano-sized PMMA particles in the environment are highly likely due to the weathering process. However, information on the hazards of nanoplastics, including PMMA in mammals, especially reproductive toxicity and action mechanism, is scarce. Herein, we investigated the effect of PMMA nanoplastics on the female reproductive system of mice embryos during pre-implantation. The treated plastic particles in embryos (10, 100, and 1000 μg/mL) were endocytosed into the cytoplasm within 30 min, and the blastocyst development and indices of embryo quality were significantly decreased from at 100 μg/mL. Likewise, the transfer of nanoplastic-treated embryos at 100 μg/mL decreased the morula implantation rate on the oviduct of pseudopregnant mice by 70%, calculated by the pregnant individual, and 31.8% by the number of implanted embryos. The PMMA nanoplastics at 100 μg/mL significantly increased the cellular levels of reactive oxygen species in embryos, which was not related to the intrinsic oxidative potential of nanoplastics. This study highlights that the nanoplastics that enter systemic circulation can affect the early stage of embryos. Thus, suitable action mechanisms can be designed to address nanoplastic occurrence.

Microplastic pollution differences in freshwater river according to stream order: Insights from spatial distribution, annual load, and ecological assessment

Microplastic (MP) pollution has become a pressing concern in global freshwater ecosystems because rivers serve as essential channels for the transport of terrestrial debris to the ocean. The current researches mostly focus on the large catchments, but the impact on the small catchments remains underexplored. In this study, we employed Strahler's stream order classification to delineate the catchment structure of the Beijiang River in South China. The distribution pattern of MP contamination and the factors influencing the distribution pattern, were assessed across the streams at different orders. We found that the Beijiang River was moderately polluted compare to other rivers in China, with an average MP abundance of 2.15 ± 1.65 items/L. MP abundance ranged from 3.17 to 1.45 items/L in the streams at different orders, and significantly decreased with increasing stream order (R2 = 0.93). This highlights the key role of small rivers as the channels for the transport of MPs from watersheds to main streams. The high abundance of PP and PE fibers, the high correlation between the stream order and the resin proportion (R2 = 0.89), and the significant correlation between MP abundance and proximity to urban centers (P = 0.02), indicated that MP pollution across the streams at different orders was predominantly influenced by anthropogenic activities, rather than natural environmental factors. By integrating MP data with hydrographic information, the annual MP loads for the streams at Orders 1 to Order 5 were estimated to be 4.63, 39.38, 204.63, 503.06, and 1137.88 tons/yr, respectively. Additionally, an ecological risk assessment indicates that MP pollution led to a low risk in the Beijiang River. Our findings deepen the understanding of MP pollution within freshwater river networks, and emphasize the crucial role of tributary systems in transporting MPs to main river channels.

Modeling of Microplastics Migration in Soil and Groundwater: Insights into Dispersion and Particle Property Effects

Migration of microplastics (MPs) in soil-groundwater systems plays a pivotal role in determining its concentration in aquifers and future threats to the terrestrial environment, including human health. However, existing models employing an advection-dispersion equation are insufficient to incorporate the holistic mechanism of MP migration. Therefore, to bridge the gap associated with MP migration in soil-groundwater systems, a dispersion-drag force coupled model incorporating a drag force on MPs along with dispersion is developed and validated through existing laboratory and field-scale experiments. The inclusion of the MP dispersion notably increased the global maximum particle velocity (vmaxp) of MPs, resulting in a higher concentration of MPs in the aquifer, which is also established by sensitivity analysis of MP dispersion. Additionally, increasing irrigation flux and irrigation areas significantly accelerates MP migration downward from soil to deep saturated aquifers. Intriguingly, vmaxp of MPs exhibited a nonlinear relationship with MPs' sizes smaller than 20 μm reaching the highest value (=1.64 × 10-5 m/s) at a particle size of 8 μm, while a decreasing trend was identified for particle sizes ranging from 20 to 100 μm because of the hindered effect by porous media and the weaker effect of the drag force. Moreover, distinct behaviors were observed among different plastic types, with poly(vinyl chloride), characterized by the highest density, displaying the lowest vmaxp and minimal flux entering groundwater. Furthermore, the presence of a heterogeneous structure with lower hydraulic conductivity facilitated MP dispersion and promoted their migration in saturated aquifers. The findings shed light on effective strategies to mitigate the impact of MPs in aquifers, contributing valuable insights to the broader scientific fraternity.

Chronic Polystyrene Microplastic Exposure Reduces Testosterone Levels in Mice through Mitochondrial Oxidative Stress and BAX/BCL2-Mediated Apoptosis

Microplastics (MPs) have emerged as a major environmental issue. They have been found to cause significant reproductive toxicity and lower testosterone levels in adult males, though the exact mechanisms remain unclear. In this study, C57bl/6 mice were orally exposed to saline or varying doses (0.25, 0.5, and 1 mg/day) of 5 μm polystyrene MPs (PS-MPs) for 4 weeks, and TM3 mouse Leydig cells were treated with different concentrations of PS-MPs. Our results found that exposure to PS-MPs significantly reduced testosterone levels and impaired the synthesis function of testicular steroids. In vitro, PS-MPs reduced steroid synthesis in Leydig cells. Treatment with PS-MPs significantly increased the apoptosis rate and BAX/BCL2 ratio in Leydig cells. Additionally, GSH-px and SOD activities decreased, while MDA levels increased, along with a rise in mitochondrial ROS. In conclusion, chronic PS-MP exposure reduced testosterone levels in mice through mitochondrial oxidative stress and BAX/BCL2-mediated apoptosis. This study offers new insights into the health risks posed by MPs.

Size-classifiable quantification of nanoplastic by rate zonal centrifugation coupled with pyrolysis-gas chromatography-mass spectrometry

Particle size is an important indicator to evaluate the environmental risk and biotoxicity of nanoplastic (NP, particle diameter <1000 nm). The methods available to determine size classes of NP in environmental samples are few and are rare to achieve efficient separation and recycling of NP with close particle sizes. Here, we show that rate-zonal centrifugation (RZC) can quickly and efficiently collect NP of different sizes based on their sedimentation coefficients. When combined with cloud-point extraction (CPE) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), our method can quantify three NP particle-size classes separately (including 100 nm, 300 nm, and 600 nm) in aqueous samples with high recovery (81.4 %-89.4 %), limits of detections (LODs, 33.5-53.4 μg/L), and limits of quantifications (LOQs, 110.6-167.2 μg/L). Compared with the conventional sample pretreatment process, our method can effectively extract and determine the NP with different sizes. Our approach is highly scalable and can be effectively applied to NP in a wide range of aquatic environments. Meanwhile, our approach is highly scalable to incorporate diverse assays to study the environmental behaviours and ecological risks of NP.

Research advances on microplastics contamination in terrestrial geoenvironment: A review

The contamination of microplastics in terrestrial geoenvironment (CMTG) is widespread and severe and has, received considerable attention. However, studies on CMTG are in their initial stages. The literature on CMTG published in the past decade was analyzed through bibliometric analysis, such as the annual publications, countries with the highest contributions, prolific authors, and author keywords. The sources, compositions, migrations and environmental impacts of CMTG are summarized, and possible future directions are proposed. This study analyzed the annual publications, countries with the highest contributions, prolific authors, and author keywords related to microplastics. The results demonstrated that 15,306 articles were published between 2014 and 2023. China is the leading country in terms of the total number of publications. The main sources of CMTG include landfills, agricultural non-point sources, sewage treatment systems and transportation systems. The composition of the CMTG exhibits significantly temporal and spatial variability from different sources. The migration paths of the CMTG were within the soil, groundwater seepage and wind transportation of suspended particles. Microplastics increase soil cohesion, decrease porosity, reduce pore scale, decrease air circulation, and increase water retention capacity, and the exudation of highly water-soluble additives in microplastics can cause secondary contamination of geological entities. Microplastics have an adverse effect on plant growth, animal digestion, microbial activity, energy and lipid metabolism, oxidative stress, and respiratory diseases in humans. It is recommended to develop more efficient and convenient quantitative testing methods for microplastics, formulate globally harmonized testing and evaluation standards, include microplastic testing in testing programs for contaminated soils, and develop efficient methods for the remediation of microplastic contaminated geological bodies.

Microplastic exposure disturbs sleep structure, reduces lifespan, and decreases ovary size in Drosophila melanogaster

The organ-specific toxicity resulting from microplastic (MP) exposure has been extensively explored, particularly concerning the gut, liver, testis, and lung. However, under natural conditions, these effects are not restricted to specific organs or tissues. Investigating whether MP exposure presents a systemic threat to an entire organism, impacting factors such as lifespan, sleep, and fecundity, is essential. In this study, we investigated the effects of dietary exposure to two different doses of MPs (1-5 μm) using the terrestrial model organism Drosophila melanogaster. Results indicated that the particles caused gut damage and remained within the digestive system. Continuous MP exposure significantly shortened the lifespan of adult flies. Even short-term exposure disrupted sleep patterns, increasing the length of daytime sleep episodes. Additionally, one week of MP exposure reduced ovary size, with a trend towards decreased egg-laying in mated females. Although MPs did not penetrate the brain or ovaries, transcriptome analysis revealed altered gene expression in these tissues. In the ovary, Gene Ontology (GO) analysis indicated genotoxic effects impacting inflammation, circadian regulation, and metabolic processes, with significant impacts on extracellular structure-related pathways. In the brain, GO analysis identified changes in pathways associated with proteolysis and carbohydrate metabolism. Overall, this study provides compelling evidence of the systemic negative effects of MP exposure, highlighting the urgent need to address and mitigate environmental MP pollution.

Microplastic co-exposure elevates cadmium accumulation in mouse tissue after rice consumption: Mechanisms and health implications

Rice cadmium (Cd) and microplastics are prevalent contaminants, posing a co-exposure threat to humans by means of dietary intake. To assess whether co-exposure of microplastics affects the bioavailability of rice Cd, mice were exposed to Cd-contaminated rice with microplastic co-exposure. We found that polyethylene (PE), polystyrene (PS), polypropylene (PP), and polyamide (PA) microplastic co-exposure via diet consumption (2 μg g-1) caused 1.17-1.38-fold higher Cd accumulation in tissue of mice fed by Cd-rice. For mice with co-exposure of PE microplastics, the higher rice-Cd bioavailability corresponded to colonization of Lactobacillus reuteri (38.9 % vs 17.5 %) in the gut compared to control mice, which caused higher production of gut metabolites particularly peptides, likely causing a 'side effect' of elevating Cd solubility in the intestinal lumen. In addition, abundance of sphingosine 1-phosphate in the gut of mice was reduced under PE microplastic exposure, which may reduce intracellular calcium ions (Ca2+) in enterocytes and form a weaker competition in pumping of intracellular Ca2+ and Cd2+ across the basolateral membrane of enterocytes, leading to higher Cd2+ transport efficiency. The results suggest elevated Cd exposure risk from rice consumption with microplastic co-exposure at environmentally relevant low concentrations.

Transitioning to Microplastic-Free Seed Coatings: Challenges and Solutions

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

Polystyrene Nanoplastics Induce Lipid Metabolism Disorder by Activating the PERK-ATF4 Signaling Pathway in Mice

In recent years, the study of microplastics (MPs) and nanoplastics (NPs) and their effects on human health has gained significant attention. The impacts of NPs on lipid metabolism and the specific mechanisms involved remain poorly understood. To address this, we utilized high-throughput sequencing and molecular biology techniques to investigate how endoplasmic reticulum (ER) stress might affect hepatic lipid metabolism in the presence of polystyrene nanoplastics (PS-NPs). Our findings suggest that PS-NPs activate the PERK-ATF4 signaling pathway, which in turn upregulates the expression of genes related to lipid synthesis via the ATF4-PPARγ/SREBP-1 pathway. This activation leads to an abnormal accumulation of lipid droplets in the liver. 4-PBA, a known ER stress inhibitor, was found to mitigate the PS-NPs-induced lipid metabolism disorder. These results demonstrate the hepatotoxic effects of PS-NPs and clarify the mechanisms of abnormal lipid metabolism induced by PS-NPs.

Human exposure to microplastics via the consumption of nonalcoholic beverages in various packaging materials: The case of Hong Kong

There is growing concern over microplastics in food and beverages, with potential implications for human health. However, little is known about microplastics in nonwater, nonalcoholic packaged beverages. This study addresses this research gap by implementing a dual-method approach that includes laboratory analysis to quantify microplastics in 50 packaged nonalcoholic beverages sold in Hong Kong, coupled with a beverage frequency questionnaire survey to provide a more accurate estimate of microplastic intake from these beverages. The beverages analysed spanned five categories-juice drinks, ready-to-drink teas, soda waters, soft drinks, and sports and energy drinks-and were packaged in four forms: aluminium cans, aseptic cartons, plastic bottles and glass bottles. The results showed that all beverage samples contained microplastics, with an average abundance of 42.1 ± 41.2 n/L (interquartile range [IQR]: 17.8-54.1 n/L), and these particles were predominantly smaller than 150 µm in size. Additionally, based on an annual beverage consumption rate of 157.3 ± 209.7 L/capita (IQR: 42.9-183.0 L/capita), it is estimated that Hong Kong adults ingest approximately 6200 microplastics per capita each year. The potential primary sources of these microplastics are atmospheric fallout and the packaging materials that endure mechanical stresses during the manufacturing and transportation of beverages. Compared to other known routes of exposure, including air, seafood, sugar, salt and honey, packaged nonalcoholic beverages present a comparable level of microplastic exposure, being lower than the first three but higher than the latter two. Nevertheless, the high prevalence of smaller microplastics in the samples is concerning. This study is considered to be important for food safety and human health, as it not only raises public awareness about microplastic contamination in packaged beverages but also serves as a call to action for the beverage industry to adopt more robust safety measures and for policymakers to revise packaging standards to reduce microplastic contamination and safeguard public health.

Microplastics and Anthropogenic Particles in Recreationally Caught Freshwater Fish from an Urbanized Region of the North American Great Lakes

BACKGROUND

Microplastics are a pervasive contaminant cycling through food webs-leading to concerns regarding exposure and risk to humans.

OBJECTIVES

We aimed to quantify and characterize anthropogenic particle contamination (including microplastics) in fish caught for human consumption from the Humber Bay region of Lake Ontario. We related quantities of anthropogenic particles to other factors (e.g., fish size) that may help in understanding accumulation of microplastics in fish.

METHODS

A total of 45 samples of six fish species collected from Humber Bay in Lake Ontario near Toronto, Ontario, Canada, were examined for anthropogenic particles in their gastrointestinal (GI) tracts and fillets. Using microscopy and spectroscopy, suspected anthropogenic particles were identified and characterized.

RESULTS

We observed anthropogenic particles in the GI tracts and fillets of all species. Individual fish had a mean ± standard deviation of 138 ± 231 anthropogenic particles, with a single fish containing up to 1,508 particles. GI tracts had 93 ± 226 particles/fish (9.8 ± 32.6 particles/gram), and fillets had 56 ± 61 particles/fish (0.5 ± 0.8 particles/gram). Based on a consumption rate of 2 servings/week, the average yearly human exposure through the consumption of these fish fillets would be 12,800 ± 18,300 particles.

DISCUSSION

Our findings suggest that consumption of recreationally caught freshwater fish can be a pathway for human exposure to microplastics. The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics. Currently, it is unclear what the effects of ingesting microplastics are for humans, but given that recreationally caught freshwater fish are one pathway for human exposure, these data can be incorporated into future human health risk assessment frameworks for microplastics. https://doi.org/10.1289/EHP13540.

Transforming pollution into solutions: A bibliometric analysis and sustainable strategies for reducing indoor microplastics while converting to value-added products

Microplastics (MPs), as emerging indoor contaminants, have garnered attention due to their ubiquity and unresolved implications for human health. These tiny particles have permeated indoor air and water, leading to inevitable human exposure. Preliminary evidence suggests MP exposure could be linked to respiratory, gastrointestinal, and potentially other health issues, yet the full scope of their effects remains unclear. To map the overall landscape of this research field, a bibliometric analysis based on research articles retrieved from the Web of Science database was conducted. The study synthesizes the current state of knowledge and spotlights the innovative mitigation strategies proposed to curb indoor MP pollution. These strategies involve minimizing the MP emission from source, advancements in filtration technology, aimed at reducing the MP exposure. Furthermore, this research sheds light on cutting-edge methods for converting MP waste into value-added products. These innovative approaches not only promise to alleviate environmental burdens but also contribute to a more sustainable and circular economy by transforming waste into resources such as biofuels, construction materials, and batteries. Despite these strides, this study acknowledges the ongoing challenges, including the need for more efficient removal technologies and a deeper understanding of MPs' health impacts. Looking forward, the study underscores the necessity for further research to fill these knowledge gaps, particularly in the areas of long-term health outcomes and the development of standardized, reliable methodologies for MP detection and quantification in indoor settings. This comprehensive approach paves the way for future exploration and the development of robust solutions to the complex issue of microplastic pollution.

The Impact of Virgin and Aged Microstructured Plastics on Proteins: The Case of Hemoglobin Adsorption and Oxygenation

Plastic particles, particularly micro- and nanoparticles, are emerging pollutants due to the ever-growing amount of plastics produced across a wide variety of sectors. When plastic particles enter a biological medium, they become surrounded by a corona, giving them their biological identity and determining their interactions in the living environment and their biological effects. Here, we studied the interactions of microstructured plastics with hemoglobin (Hb). Virgin polyethylene microparticles (PEMPs) and polypropylene microparticles (PPMPs) as well as heat- or irradiation-aged microparticles (ag-PEMPs and ag-PPMPs) were used to quantify Hb adsorption. Polypropylene filters (PP-filters) were used to measure the oxygenation of adsorbed Hb. Microstructured plastics were characterized using optical microscopy, SAXS, ATR-FTIR, XPS, and Raman spectroscopy. Adsorption isotherms showed that the Hb corona thickness is larger on PPMPs than on PEMPs and Hb has a higher affinity for PPMPs than for PEMPs. Hb had a lower affinity for ag-PEMPs and ag-PPMPs, but they can be adsorbed in larger amounts. The presence of partial charges on the plastic surface and the oxidation rate of microplastics may explain these differences. Tonometry experiments using an original method, the diffuse reflection of light, showed that adsorbed Hb on PP-filters retains its cooperativity, but its affinity for O2 decreases significantly.

Pollution characteristics and prospective risk of microplastics in the Zhengzhou section of Yellow River, China

The ubiquitous occurrence of microplastics (MPs) in the freshwater has attracted widespread attention. The Zhengzhou section of the Yellow River was the most prosperous region in ancient China, and the rapid urbanization, industrialization, and agricultural practices contributed to MPs pollution in aquatic systems recently, whereas the contamination status of MPs in the area is still not available. In this study, a total of fourteen sampling cross-sections were selected in the region to collect water samples systematically for the analysis of MPs pollution characteristics and potential risks. Results showed that abundance of MPs in the water were ranged from 2.33 to 15.50 n/L, with an average value of 6.40 ± 3.40 n/L, which was higher than it in other inland rivers from China. Moreover, the MPs of 0.5-2 mm were the dominant sizes in Yellow River of Zhengzhou region, and most of them were black fibres. The top three polymers were Polyethylene terephthalate (PET), Polyamide (PA) and Polypropylene (PP). High diversity indices of MPs observed at S3, S4, S5, S6, S7, and S8 for size, colour, polymer and shape indicated diverse and complex sources of MPs in those cross-sections. The MPs in water from Zhengzhou area of Yellow River probably degraded from textiles, fishing net, plastic bags, mulching film, packaging bags, and tire wear. The chemical risk assessment revealed a level III risk for study area, while S8 and S11 in which PVA or PAN with higher hazard score detected were categorised as class V risk. Coincidentally, probabilistic risk assessment showed a considerable ecological risk of MPs from Yellow River in Zhengzhou City, with possibility of 99.48 and 98.01 % adverse effect for food dilution and translocation-mediated mechanism, respectively. The results are expected to assistance for development of policies and ultimately combating MPs pollution.

Microplastic Contamination of Non-Mulched Agricultural Soils in Bangladesh: Detection, Characterization, Source Apportionment and Probabilistic Health Risk Assessment

Microplastic contamination in agricultural soil is an emerging problem worldwide as it contaminates the food chain. Therefore, this research investigated the distribution of microplastics (MPs) in agricultural soils without mulch at various depths (0-5, 5-10, and 10-15 cm) across different zones: rural, local market, industrial, coastal, and research areas. The detection of MP types and morphology was conducted using FTIR and fluorescence microscopy, respectively. Eight types of MPs were identified, including high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinyl fluoride (PVF), polyvinyl alcohol (PVA), and polytetrafluoroethylene (PTFE), with concentrations ranging from 0.6 ± 0.21 to 3.71 ± 2.36 MPs/g of soil. The study found no significant trends in MP concentration, with ranges of 0-2.1 ± 0.38, 0-2.87 ± 0.55, and 0-2.0 ± 0.34 MPs/g of soil at depths of 0-5 cm, 5-10 cm, and 10-15 cm, respectively. The highest MP quantity was recorded at 8.67 in coastal area, while the lowest was 6.44 in the local market area. Various MP shapes, e.g., fiber, film, pellet, fragment, and irregular, were observed across all layers. PCA suggested irrigation and organic manure as potential sources of MPs. The estimated concentrations of MPs possessed low non-carcinogenic and carcinogenic risks to the farming community of Bangladesh.

Features, Potential Invasion Pathways, and Reproductive Health Risks of Microplastics Detected in Human Uterus

Microplastics (MPs) are ubiquitous in global ecosystems and may pose a potential risk to human health. However, critical information on MP exposure and risk to female reproductive health is still lacking. In this study, we characterized MPs in human endometrium and investigated their size-dependent entry mode as well as potential reproductive toxicity. Endometrial tissues of 22 female patients were examined, revealing that human endometrium was contaminated with MPs, mainly polyamide (PA), polyurethane (PU), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyethylene (PE), ranging from 2-200 μm in size. Experiments conducted in mice demonstrated that the invasion of the uterus by MPs was modulated either through diet-blood circulation (micrometer-sized particles) or via the vagina-uterine lacuna mode (larger particles reaching a size of 100 μm. Intravenous exposure to MPs resulted in reduced fertility and abnormal sex ratio in mouse offspring (P < 0.05). After 3.5 months of intragastric exposure, there was a significant inflammatory response in the endometrium (P < 0.05), confirmed by embryo transfer as a uterine factor leading to decreased fertility. Furthermore, human endometrial organoids cultured with MPs in vitro exhibited significantly apoptotic responses and disrupted growth patterns (P < 0.01). These findings raise significant concerns regarding MP contamination in the human uterus and its potential effects on reproductive health.

Microplastic and PTFE contamination of food from cookware

Microplastics are a prolific environmental contaminant that have been evidenced in human tissues. Human uptake of microplastic occurs via inhalation of airborne fibres and ingestion of microplastic-contaminated foods and beverages. Plastic and PTFE-coated cookware and food contact materials may release micro- and nanoplastics into food during food preparation. In this study, the extent to which non-plastic, new plastic and old plastic cookware releases microplastics into prepared food is investigated. Jelly is used as a food simulant, undergoing a series of processing steps including heating, cooling, mixing, slicing and storage to replicate food preparation steps undertaken in home kitchens. Using non-plastic cookware did not introduce microplastics to the food simulant. Conversely, using new and old plastic cookware resulted in significant increases in microplastic contamination. Microplastics comprised PTFE, polyethylene and polypropylene particulates and fibrous particles, ranging 13-318 μm. Assuming a meal was prepared daily per the prescribed methodology, new and old plastic cookware may be contributing 2409-4964 microplastics per annum into homecooked food. The health implications of ingesting microplastics remains unclear.

Occurrence of microplastics and metals in European seabass produced in different aquaculture systems: Implications for human exposure, risk, and food safety

Microplastics (MPs) are emerging contaminants of increasing concern as they may cause adverse effects and carry other contaminants, which may potentially compromise human health. Despite occurring in aquatic ecosystems worldwide, the knowledge about MP presence in different aquaculture systems and their potential impact on seafood products is still limited. This study aimed to determine the levels of MPs in water, feed, and European seabass (Dicentrarchus labrax) from three relevant aquaculture systems and estimate human exposure to MPs and metals through seabass consumption. The recirculating aquaculture system (RAS) had the highest MP occurrence in water and feed. MP levels in seabass followed the aquaculture system's levels in water and feed, with RAS-farmed fish presenting the highest MP load, both in the fish gastrointestinal tract (GIT) and muscle, followed by pond-, and cage-farmed fish. MPs' characteristics across aquaculture systems and fish samples remained consistent, with the predominant recovered particles falling within the MP size range. The particles were visually characterized and chemically identified by micro-Fourier Transform Infrared Spectroscopy (μFTIR). Most of these particles were fibres composed of man-made cellulose and PET. MP levels in GIT were significantly higher than in muscle for pond- and RAS-farmed fish, MPs' bioconcentration factors >1 indicated bioconcentration in farmed seabass. Metal concentrations in fish muscle were below permissible limits, posing low intake risks for consumers according to the available health-based guidance values and estimated dietary scenarios.

Desorption of Polycyclic Aromatic Hydrocarbons from Microplastics in Human Gastrointestinal Fluid Simulants-Implications for Exposure Assessment

Microplastics have been detected in various food types, suggesting inevitable human exposure. A major fraction may originate from aerial deposition and could be contaminated by ubiquitous pollutants such as polycyclic aromatic hydrocarbons (PAHs). While data on the sorption of pollutants to microplastics are abundant, the subsequent desorption in the gastrointestinal tract (GIT) is less understood. This prompted us to systematically investigate the release of microplastics-sorbed PAHs at realistic loadings (44-95 ng/mg) utilizing a physiology-based in vitro model comprising digestion in simulated saliva, gastric, and small and large intestinal fluids. Using benzo[a]pyrene as a representative PAH, desorption from different microplastics based on low density polyethylene (LDPE), thermoplastic polyurethanes (TPUs), and polyamides (PAs) was investigated consecutively in all four GIT fluid simulants. The cumulative relative desorption (CRD) of benzo[a]pyrene was negligible in saliva simulant but increased from gastric (4 ± 1% - 15 ± 4%) to large intestinal fluid simulant (21 ± 1% - 29 ± 6%), depending on the polymer type. CRDs were comparable for ten different microplastics in the small intestinal fluid simulant, except for a polydisperse PA-6 variant (1-10 μm), which showed an exceptionally high release (51 ± 8%). Nevertheless, the estimated contribution of microplastics-sorbed PAHs to total human PAH dietary intake was very low (≤0.1%). Our study provides a systematic data set on the desorption of PAHs from microplastics in GIT fluid simulants.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.