Lifetime Accumulation of Microplastic in Children and Adults

Evidence of microplastic accumulation on the surface of lettuce and analysis of contamination sources

Microplastic (MP) pollution has emerged as a significant environmental concern. Microplastics land on vegetable surfaces with airborne deposition and agronomic activities. However, research on the sources of microplastics on vegetable surfaces is limited by the lack of monitoring of microplastics in the growing environment. Therefore, we detected microplastics on lettuce surfaces, in air, and in pesticides to determine the correlation between them. In addition, this study compared microplastics on the surface of different types of lettuce to explore their differences. The results showed that the content, in descending order, was old leaves of leaf lettuce > new leaves of leaf lettuce > nodular lettuce. A total of 19 polymers, mainly polyamide polyethylene and polypropylene, were detected on the surface of the lettuce. The contribution of microplastics on the surface of lettuce was air and pesticides in descending order of origin. Microplastic risk assessment index was determined that the risk level of microplastics on lettuce surfaces could be classed as level IV, indicating a high dietary health risk. The results presented here will enable scientific assessments of the exposure pathways of MPs in fresh vegetables and their potential harm to human health.

Synergistic human health risks of microplastics and co-contaminants: A quantitative risk assessment in water

The pervasive presence of microplastics (MPs) in aquatic environments, coupled with their potential to act as vectors for toxic contaminants, raises significant concerns for human health. This study quantifies the health risks associated with the ingestion of microplastics and their co-contaminants in aquatic medium, considering both individual and interactive effects. The analysis encompasses four MP types (PP, PS, PET, PE) and prevalent contaminants including heavy metals (Cr, Cu, Ni, Pb), polycyclic aromatic hydrocarbons (PAHs, expressed as BaP equivalents), and plastic additives (DEHP, DBP, BPA)-to calculate individual Hazard Quotient (HQ), interaction-based Hazard Index (HIint), individual Incremental Lifetime Cancer Risk (ILCR), and interaction-based ILCR (ILCRint). The mean concentration of MPs in aqueous media was determined to be 2.19 mg/L (95 % CI), and Chronic Daily Intake (CDI) values were derived from particle counts converted to mass using polymer-specific densities. Reference Dose (RfD) values were calculated using the Weight of Evidence (WoE) approach, which integrates findings from rodent toxicity studies, identifying PP and PS as having low RfD values 25 × 10⁻⁴ mg/kg bw/day and 8 × 10⁻⁴ mg/kg bw/day, respectively. HQ-based toxicity rankings indicated the order of risk as PP > PS > PE > PET. Findings revealed a pronounced HIint of 18.646 × 10³ and 16.649 × 10⁶ at the 50th and 90th percentiles in children, underscoring significant synergistic effects from combined exposure to MPs and leached plastic additives. Co-contaminant scenarios further escalated health risks, with HI values reaching 52.236 in the presence of heavy metals and 53.141 with PAHs. The maximum allowable MP concentration, considering additive leaching, was estimated at 0.011 mg/L. This research highlights the need for firstly understanding the transformations of microplastic in the aquatic medium along with co-contaminants and framing regulatory measures and improved monitoring to protect human health from the growing threat of microplastic pollution. By integrating exposure modeling, dose-response assessment, and Monte Carlo simulations, the study delivers a robust framework for environmental health guidelines. It emphasizes the complex, multifaceted risks MPs pose and their associated contaminants, calling for innovative solutions to safeguard public health against this pervasive environmental challenge.

Assessing strategies for remote island beach cleanups: Lessons from the Pacific and Alaska

Plastic pollution is a pervasive environmental challenge, with significant ecological, economic, and social implications. While upstream solutions are essential, downstream cleanup efforts play a role in addressing existing and legacy pollution. This study assesses strategies for remote island beach cleanups through two case studies: Henderson Island in the South Pacific and Kruzof Island in Southeast Alaska. These regions, characterized by their isolation and heavy plastic pollution, highlight unique logistical, ecological, and social challenges in cleanup operations. Drawing on firsthand observations, this research identifies key strategies for effective cleanups in remote locations. The findings emphasize the importance of careful planning, local engagement and innovative technologies to balance the benefits of cleanup with the potential costs. The study describes cases using a six-step cleanup framework and evaluates cleanup strategies based on feasibility, cost-effectiveness, potential harms, and co-benefits. This research contributes to literature on innovative approaches to marine debris management.

Microplastics accumulate in all major organs of the mediterranean loggerhead sea turtle (Caretta caretta)

Microplastics (MPs) are a pervasive marine environmental pollutant, posing a serious threat to marine ecosystems and organisms at all trophic levels. Plastic ingestion is well documented in marine turtles, and loggerhead sea turtles (Caretta caretta) have been identified as an indicator species to monitor MP pollution globally. Our understanding of the translocation and bioaccumulation potential of MPs beyond the gastrointestinal tract is, however, limited. Here we demonstrate that MP translocation occurs in these marine reptiles and present a comprehensive analysis of MP accumulation in body tissues of 10 stranded Mediterranean loggerhead turtles including the kidney, liver, spleen, heart, skeletal muscle, subcutaneous fat, stomach, intestine, and reproductive organs. Foreign microparticles were identified in 98.8 % of all samples (∼70 % being MPs) and were significantly concentrated in the reproductive organs followed by the heart. Raman spectroscopy revealed that polypropylene, cotton fibres, and polyethylene were the most common microparticle types, and optical photothermal infrared (O-PTIR) spectroscopy provided direct visualisation of cotton microfibres embedded in loggerhead heart tissue. Future studies should determine the biological impact of MP bioaccumulation in sea turtle organs, to fully appreciate the impacts of these anthropogenic pollutants on protected and vulnerable populations worldwide.

Microplastics in urine, sputum and lung lavage fluid from patients with respiratory illnesses

Because of the ubiquity of microplastics (MPs) in the environment there are concerns regarding human exposure. In this study, MPs have been determined in three physiological fluids: urine, sputum and bronchoalveolar fluid (BALF); from 30 adult patients in Iran with respiratory conditions. A total of nine small (20-100 μm) and mainly green and red fibres of polyethylene, polypropylene and polystyrene construction were detected in urine samples of eight participants. By contrast, 358 MPs that were dominated by small, white and transparent fibres, but also included larger (100-500 μm) fibres and fragments and spherules of various sizes, were detected in sputum samples. Here, a broader range of polymers was identified but polyurethane was dominant. In BALF samples, 123 MPs were detected that included a higher proportion of larger fibres, along with fragments and spherules. The colour distribution of these MPs was similar to that of sputum samples but polymer distribution was closer to that of urine samples. These observations suggest that MPs that are inhaled and ingested might be fractionated differently though the body. Further research is required to elucidate how particles larger than theoretical limits (set by filtration mechanisms) are present in physiological fluids, what fractionation processes are present, and whether ingested or inhaled MPs are responsible for acute and chronic health impacts.

Influence of non-degradable and degradable microplastics on the bioavailability of per- and polyfluoroalkyl substance in mice: Mechanism exploration

Per- and polyfluorinated alkyl substances (PFAS) contamination in drinking water and their associated health risks have received extensive global attention. Microplastics (MPs), which commonly coexist with PFAS in the daily diet, remain poorly understood in terms of their effects on PFAS bioavailability. Here, we investigated the effect of non-biodegradable (PS) and biodegradable (PBS) MPs on PFAS bioavailability using a mouse model, with PFAS level in drinking water being at 20 μg/L. High-dose dietary MPs (50 mg/g) significantly increased PFAS bioavailability, especially for PS co-exposure (29.2 ± 5.09 % vs 19.4 ± 3.66 % in control, p < 0.05), while reducing fecal excretion by 0.34 and 0.31-fold (p < 0.05). Mechanistic studies showed that high-dose PS significantly (p < 0.05) increased mouse serum albumin concentrations, which were closely related with the in vivo absorption of PFAS. Both PS and PBS downregulated the expression of efflux proteins (Mrp2 and Mrp4) by 0.10-0.22 fold, thereby increasing PFAS bioavailability. Molecular docking further showed that legacy PFASs (PFOA and PFOS) exhibited higher binding affinities to transport-related proteins than emerging alternatives (HFPO-TA and 6:2 FTSA), explaining their greater susceptibility to MPs co-exposure. These findings provide novel mechanistic insights into the modulation of PFAS bioavailability by co-exposure of MPs. While high MP doses were used to elucidate the mechanism, future studies using environmentally relevant exposure levels are necessary to assess the health risks of PFAS-MP co-exposure and support science-based risk management.

Unraveling the impact of micro- and nano-sized polymethyl methacrylate on gut microbiota and liver lipid metabolism: Insights from oral exposure studies

Microplastics, particularly polymethyl methacrylate (PMMA), have emerged as significant environmental pollutants, with growing concerns about their impact on various biological processes. However, the effects of chronic PMMA exposure on hepatic lipid metabolism remain insufficiently studied. This research aimed to examine the consequences of chronic exposure to PMMA particles of different sizes (100 nm and 2 μm) on hepatic lipid metabolism in mice. Female C57BL/6J mice were administered PMMA particles in drinking water over an 8-week period, and the effects on intestinal and liver morphology and function were evaluated. Histopathological analyses, gut microbiota profiling, and serum and liver assays were conducted to assess oxidative stress, lipid metabolism-related biomarkers, and liver metabolomics. The results revealed that PMMA particles accumulated in both the liver and colon, causing liver injury characterized by elevated ALT and AST levels. The exposure also induced oxidative stress by inhibiting the NRF2/HO-1 signaling pathway. Furthermore, PMMA exposure resulted in significant alterations to the gut microbiota and hepatic metabolism. These changes were linked to increased microbial diversity, which impacted cholesterol metabolism through the gut-liver axis. Additionally, the activation of the PI3K/AKT/PPARγ signaling pathway disrupted hepatic lipid metabolism, leading to increased cholesterol synthesis and hepatic lipid accumulation. This study underscores the potential of PMMA to disrupt both hepatic lipid metabolism and gut microbiota composition, suggesting a novel mechanism by which PMMA exposure could contribute to metabolic disorders and liver disease.

Differential effects of foodborne and waterborne micro(nano)plastics exposure on fish liver metabolism and gut microbiota community

Micro(nano)plastics (MNPs) primarily enter fish through two routes: directly ingestion via their diets and respiratory filtration through their gills. However, the specific impacts of these two routes on liver metabolism remain largely unknown. Here, we investigated the gene expression profiles of the liver of Nile tilapia Oreochromis niloticus following equivalent doses of foodborne and waterborne MNPs exposure. While the liver phenotypes of O. niloticus showed minimal differences between the two exposure routes, significant variations were observed in gene response patterns. Using WGCNA, we identified the key gene networks and KEGG pathways associated with each exposure type. The primary transcription factors regulating gene expression changes were thrb for foodborne exposure and fosl2 for waterborne exposure. The stimulus of foodborne MNPs primarily induced metabolic disorders through circadian rhythm, whereas waterborne MNPs induced inflammatory responses to affect host metabolism. By integrating gene expression alterations with gut microbiota enrichment data, we further found that Firmicutes, Fusobacteriota, Proteobacteria, and Chloroflexi jointly regulated the expression of mapk13 during foodborne exposure, whereas the expression of the most leading genes in waterborne exposure was predominantly influenced by Firmicutes. Collectively, our study demonstrated a distinct pattern in microbiota-gene gut-liver axis in O. niloticus in response to foodborne and waterborne MNPs exposure.

Fingerprinting risk from recycled plastic products using physical and chemical properties

The increasing production and use of recycled plastics have raised significant concerns regarding the risks associated with hazardous chemicals. The recycled plastics can accumulate potentially hazardous chemicals, many of which are unknown and unregulated. This study compared the physical and chemical characteristics of recycled plastic products intended for food, oral, or skin contact applications with similar virgin plastic products. The results revealed significant changes in the surface morphology and elevated concentration of organic and inorganic chemicals in the recycled plastics compared to the virgin plastics. Specifically, metal(loids) concentrations were over 10 times higher, PFAS levels were twice as high, and PAH levels were three times higher in the recycled plastics. The calculated Hazard Index (HI) indicates up to a twofold increase in recycled plastics for both adults and children compared to virgin plastics, specifically through microplastic ingestion. The HI values exceed 1 for recycled plastic ingestion, therefore it falls in high-risk category due to the associated chemical exposure from microplastics.

Short-term exposure to ciprofloxacin and microplastic leads to intrahepatic cholestasis, while long-term exposure decreases energy metabolism and increases the risk of obesity

Microplastics (MPs) and antibiotics are pervasive pollutants that may pose a risk to human health. Studies have shown that both MPs and antibiotics adversely affect lipid metabolism and increase the risk of obesity. However, it remains unclear whether combined exposure to these pollutants intensify the cumulative detrimental effect on obesity and metabolism. This study demonstrated the impact of exposure to polystyrene MPs (PS, 25 nm) and ciprofloxacin (CIP), both individually and combined, for 30 d and 90 d on the hepatic metabolism of male C57BL/6J mice. The results showed that mice exposed to PS and CIP for either 30 d or 90 d exhibited lipid metabolism disorders such as increased body weight, enlarged adipocytes, triglyceride accumulation in the liver, and higher HDL-C. Differentially expressed hepatic proteins were identified via proteomic analysis. The findings indicated that exposure for 30 d caused abnormal bile acid (BA) secretion in the liver and inhibited the BA secretion pathway, which resulted in intrahepatic cholestasis. Furthermore, exposure for 90 d resolved cholestasis and reduced the overall number of differentially expressed proteins. Intestinal pathology revealed more severe damage after exposure for 30 d, while 90 d exposure decreased the adverse effect. Combined CIP and PS exposure caused damage to the organism. However, the adaptive capacity of the organism during prolonged exposure mitigated the damage caused by both, but did not imply the complete eradication of adverse effects. This study found that 90 d exposure to PS and CIP resulted in weight gain, possibly due to changes in the gut flora and suppressed energy metabolism. These results indicated that simultaneous exposure to CIP and PS exacerbated the adverse impact on the liver, causing short-term intrahepatic cholestasis. Prolonged exposure reduced the energy metabolism in the body, exhibiting varied toxicity outcomes and mechanisms at different exposure durations. This study offers novel insights into the effect of MPs and antibiotic CIP exposure on metabolic abnormalities and provides a scientific basis for assessing these risks. It also emphasizes that the adverse effect resulting from 30 d (short-term) toxic exposure may not persist and that long-term chronic toxicity needs warrants.

Microplastics Accumulation Induces Kynurenine-Derived Neurotoxicity in Cerebral Organoids and Mouse Brain

Microplastics (MP) are pervasive environmental pollutants with potential adverse effects on human health, particularly concerning neurotoxicity. This study investigates the accumulation and neurotoxic effects of MP in cerebral organoids and mouse brains. Utilizing in vitro cerebral organoids and in vivo mouse models, we examined the penetration of MP, revealing that smaller MP (50 nm) infiltrated deeper into the organoids compared to larger ones (100 nm). Exposure to 50 nm MP resulted in a significant reduction in organoid viability. Furthermore, total RNA sequencing indicated substantial alterations in neurotoxicity-related gene expression. In vivo, MP-treated mice exhibited notable DNA fragmentation in the hippocampus and cortex, alongside elevated levels of inflammatory markers and neurotoxic metabolites, such as kynurenine (KYN) and 3-hydroxykynurenine (3-HK). Our findings suggest that MP may promote neurotoxicity through the kynurenine pathway, leading to heightened levels of neurotoxic compounds like quinolinic acid. This research highlights the potential for MP to induce neuroinflammatory responses and disrupt normal brain function, underscoring the need for further investigation into the long-term effects of MP exposure on neurological health.

Toxicity of long term exposure to low dose polystyrene microplastics and nanoplastics in human iPSC-derived cardiomyocytes

Microplastics and nanoplastics (MNPs) are widespread environmental pollutants with potential risks to human health including cardiovascular effects. However, the impact of MNPs on the heart, particularly in human-relevant cardiac models, remains poorly understood. In this study, we investigated the long term effects of polystyrene (PS) MNPs-1 μm (PS-1) and 0.05 μm (PS-0.05) in human iPSC-derived cardiomyocytes (hiPSC-CMs). PS MNPs exposure reduced myocyte viability in a time- and dose-dependent manner. At a low dose of 0.1 μg/L, both PS-0.05 and PS-1 suppressed myocyte contractility, reduced Ca2+ transient amplitude, and altered contraction and Ca2+ transient dynamics. In hypertrophic hiPSC-CMs, PS-0.05 exposure exacerbated hypertrophy, increasing cell size and proBNP expression, a marker of myocyte hypertrophy. The mechanism of PS MNPs-induced cardiotoxicity likely involved mitochondrial dysfunction, as indicated by decreased mitochondrial membrane potential, increased mitochondrial ROS, and elevated intracellular ROS levels. This is the first study to assess the long term impact of low dose MNPs in human cardiomyocytes, providing crucial insight into the potential cardiac toxicity of MNPs and their implications for human heart health.

Review of Techniques for the Detection, Removal, and Transformation of Environmental Microplastics and Nanoplastics

Plastic residues have emerged as a significant challenge in the environmental sector. Microplastics, which are plastic fragments smaller than 5 mm, have the ability to disperse through the atmosphere, oceans, and land, posing a serious threat to human health by accumulating in the food chain. However, their minuscule size makes it difficult to effectively remove them from the environment using the current technologies. This work provides a comprehensive overview of recent advancements in microplastic detection and removal technologies. For detection methods, we discuss commonly used techniques such as microscopic analysis, thermal analysis, mass spectrometry, spectroscopic analysis, and energy spectrometry. We also emphasize the importance of integrating various analytical and data-processing techniques to achieve efficient and nondestructive detection of microplastics. In terms of removal strategies, we explored innovative methods and technologies for extracting microplastics from the environment. These include physical techniques like filtration, adsorption, and magnetic separation; chemical techniques such as coagulation-flocculation-sedimentation and photocatalytic conversion; and bioseparation methods such as activated sludge and biodegradation. We also highlight the promising potential for converting microplastic contaminants into high-value chemicals. Additionally, we identify current technical challenges and suggest future research directions for the detection and removal of microplastics. We advocate for the development of unified and standardized analytical methods to guide further research on the removal and transformation of microplastics.

Microplastic contamination in artificial tears in South Korea: Potential for direct ocular exposure

PURPOSE

To investigate microplastics (MP) contamination in artificial tear (AT) products.

METHOD

Five hyaluronic acid ATs (two multi-use and three disposable ATs) were used to gauge MP levels in three scenarios: 1) initial drop and remaining liquid after opening the lid upward; 2) remaining liquid after opening the lid downward and discarding two drops; and 3) remaining liquid after opening the lid downward and discarding half of it. Raman spectroscopy was used to identify the quantity, morphological characteristics, and composition of MPs. Scanning electron microscopy/energy dispersive spectroscopy was used to examine the surface traits and elements of MPs and ATs.

RESULTS

MPs were detected in 4 out of 5 ATs in the initial drops, containing 0.50 ± 0.65 particles/30 mL, whereas the remaining solution had 0.75 ± 0.72 particles/30 mL. After discarding two drops, 0.14 ± 0.35 particles/30 mL were present in the remaining solution. No MPs were detected after discarding half drops. Most MPs were transparent (95 %), irregular fragments (55 %) sized 10-20 μm (35 %), and made of polyethylene (95 %). If patients use the first drops of ATs four times a day for a year, individuals can be exposed to 730.0 particles. This exposure can be reduced to 204.4 particles by discarding the first two drops before use.

CONCLUSION

MPs are observed in commercially available ATs, and human eyes may be directly exposed to MPs through the use of ATs.

Ecological and Health Risk Mediated by Micro(nano)plastics Aging Process: Perspectives and Challenges

Aged micro(nano)plastics (MNPs) are normally the ultimate state of plastics in the environment after aging. The changes in the physical and chemical characteristics of aged MNPs significantly influence their environmental behavior by releasing additives, forming byproducts, and adsorbing contaminants. However, a systematic review is lacking on the effects of aged MNPs on ecological and human health regarding the increasing but scattered studies and results. This Review first summarizes the unique characteristics of aged MNPs and methods for quantifying their aging degree. Then we focused on the potential impacts on organisms, ecosystems, and human health, including the "Trojan horse" under real environmental conditions. Through combining meta-analysis and analytic hierarchy process (AHP) model, we demonstrated that, compared to virgin MNPs, aged MNPs would result in biomass decrease and oxidative stress increase on organisms and lead to total N/P decrease and greenhouse gas emissions increase on ecosystems while causing cell apoptosis, antioxidant system reaction, and inflammation in human health. Within the framework of ecological and human health risk assessment, we used the risk quotient (RQ) and physiologically based pharmacokinetic (PBK) models as examples to illustrate the importance of considering aging characteristics and the degree of MNPs in the process of data acquisition, model building, and formula evaluation. Given the ecological and health risks of aged MNPs, our urgent call for more studies of aged MNPs is to understand the potential hazards of MNPs in real-world environments.

Simulated Microplastic Release from Cutting Boards and Evaluation of Intestinal Inflammation and Gut Microbiota in Mice

BACKGROUND

Plastic cutting boards are commonly used in food preparation, increasing human exposure to microplastics (MPs). However, the health implications are still not well understood.

OBJECTIVES

The objective of this study was to assess the impacts of long-term exposure to MPs released from cutting boards on intestinal inflammation and gut microbiota.

METHODS

MPs were incorporated into mouse diets by cutting the food on polypropylene (PP), polyethylene (PE), and willow wooden (WB) cutting boards, and the diets were fed to mice over periods of 4 and 12 wk. Serum levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α ), interleukin-10 (IL-10), lipopolysaccharide (LPS, an endotoxin), and carcinoembryonic antigen (CEA), along with ileum and colon levels of interleukin-1β (IL-1 β ), TNF-α , malondialdehyde (MDA), superoxide dismutase (SOD), secretory immunoglobulin A (sIgA), and myosin light chain kinase (MLCK), were measured using mouse enzyme-linked immunosorbent assay (ELISA) kits. The mRNA expression of mucin 2 and intestinal tight junction proteins in mouse ileum and colon tissues was quantified using real-time quantitative reverse transcription polymerase chain reaction. Fecal microbiota, fecal metabolomics, and liver metabolomics were characterized.

RESULTS

PP and PE cutting boards released MPs, with concentrations reaching 1,088 ± 95.0 and 1,211 ± 322 μ g / g in diets, respectively, and displaying mean particle sizes of 10.4 ± 0.96 vs. 27.4 ± 1.45 μ m . Mice fed diets prepared on PP cutting boards for 12 wk exhibited significantly higher serum levels of LPS, CRP, TNF-α , IL-10, and CEA, as well as higher levels of IL-1β , TNF-α , MDA, SOD, and MLCK in the ileum and colon compared with mice fed diets prepared on WB cutting boards. These mice also showed lower relative expression of Occludin and Zonula occludens-1 in the ileum and colon. In contrast, mice exposed to diets prepared on PE cutting boards for 12 wk did not show evident inflammation; however, there was a significant decrease in the relative abundance of Firmicutes and an increase in Desulfobacterota compared with those fed diets prepared on WB cutting boards, and exposure to diets prepared on PE cutting boards over 12 wk also altered mouse fecal and liver metabolites compared with those fed diets prepared on WB cutting boards.

DISCUSSION

The findings suggest that MPs from PP cutting boards impair intestinal barrier function and induce inflammation, whereas those from PE cutting boards affect the gut microbiota, gut metabolism, and liver metabolism in the mouse model. These findings offer crucial insights into the safe use of plastic cutting boards. https://doi.org/10.1289/EHP15472.

Enhanced spectral signatures with Ag nanoarrays in hyperspectral microscopy for CNN-based microplastics classfication

Microplastics are a pervasive pollutant in aquatic ecosystems, raising critical environmental and public health concerns and driving the need for advanced detection technologies. Microscopic hyperspectral imaging (micro-HSI), known for its ability to simultaneously capture spatial and spectral information, has shown promise in microplastic analysis. However, its widespread application is hindered by limitations such as low signal-to-noise ratios (SNR) and reduced sensitivity to smaller microplastic particles. To address these challenges, this study investigates the use of Ag nanoarrays as reflective substrates for micro-HSI. The localized surface plasmon resonance (LSPR) effect of Ag nanoarrays enhances spectral resolution by suppressing background reflections and isolating microplastic reflection bands from interference. This improvement results in significantly increased SNR and more distinct spectral features. When analyzed using a 3D-2D convolutional neural network (3D-2D CNN), the integration of Ag nanoarrays improved classification accuracy from 90.17% to 98.98%. These enhancements were further validated through Support Vector Machine (SVM) analyses, demonstrating the robustness and reliability of the proposed approach. This study demonstrates the potential of combining Ag nanoarrays with 3D-2D CNN models to enhance micro-HSI performance, offering a novel and effective solution for precise microplastics detection and advancing chemical analysis, environmental monitoring, and related fields.

From automated Raman to cost-effective nanoparticle-on-film (NPoF) SERS spectroscopy: A combined approach for assessing micro- and nanoplastics released into the oral cavity from chewing gum

Microplastics (MPs) and Nanoplastics (NPs), a burgeoning health hazard, often go unnoticed due to suboptimal analytical tools, making their way inside our bodies through various means. Surface Enhanced Raman Spectroscopy (SERS), although is utilized in detecting NPs, challenges arise at low concentrations due to their low Raman cross section and inability to situate within hotspots owing to their ubiquitous size and shape. This study presents an innovative and cost-effective approach employing household metallic foils (aluminium and copper) as nanoparticle-on-film (NPoF) substrates for targeting such analytes. Leveraging from the near field enhancements due to plasmonic coupling amidst third-generation hotspots (TGHs) and second-generation hotspots (SGHs), the enhanced SERS activity is achieved. Furthermore, following an extensive comparison of the substrates' flexibility, sensitivity, reproducibility, and robustness, the copper foil-based NPoF platform was used to detect 100 nm polystyrene plastics down to 1 μg/ml concentration. Subsequently, a systematic detection of more than 250,000 MPs with automated Raman spectroscopy was performed, followed by the detection of NPs using SERS with a NPoF substrate in saliva samples released from the gum base in the oral cavity during a one-hour chewing activity. Overall, we report a cost-effective and versatile NPoF substrate, having the potential to screen a diverse array of environmental pollutants envisioned as a potential point-of-site tool by coupling it with a handheld Raman instrument.

Screening method for differentiation of plastic and non-plastic microparticles contaminating store-bought rice

This article presents a simple and low-cost screening method based on optical microscopy and FT-IR spectroscopy for assessing microparticles found in rice. Five brands of rice packed in paper and foil bags from both the European Union (EU) and non-EU region were tested. Microparticles of various shapes have been found in the rice regardless of the packaging type and origin of the rice. The content of microparticles varies depending on the sample, from 2 to even 12 items per 1 g of rice. Overall, the abundance of microparticles is higher in the case of rice packed in foil bags. Not all identified microparticles are microplastics, but those that are microplastics cannot be directly linked to the composition of the rice package. For a cursory analysis aimed at distinguishing the infrared spectra of non-plastic microparticles (i.e. rice, paper or cellulose) from microplastics, it is sufficient only to analyse the absorption bands above 2800 cm-1.

Deciphering the phenotypic, inflammatory, and endocrine disrupting impacts of e-waste plastic-associated chemicals

As the volume of plastic waste from electrical and electronic equipment (WEEE) continues to rise, a significant portion is disposed of in the environment, with only a small fraction being recycled. Both disposal and recycling pose unknown health risks that require immediate attention. Existing knowledge of WEEE plastic toxicity is limited and mostly relies on epidemiological data and association studies, with few insights into the underlying toxicity mechanisms. Therefore, this study aimed to perform comprehensive chemical screening and mechanistic toxicological assessment of WEEE plastic-associated chemicals. Chemical analysis, utilizing suspect screening based on high-resolution mass spectrometry, along with quantitative target chemical analysis, unveiled numerous hazardous compounds including polyaromatic compounds, organophosphate flame retardants, phthalates, benzotriazoles, etc. Toxicity endpoints included perturbation of morphological phenotypes using the Cell Painting assay, inflammatory response, oxidative stress, and endocrine disruption. Results demonstrated that WEEE plastic chemicals altered the phenotypes of the cytoskeleton, endoplasmic reticulum, and mitochondria in a dose-dependent manner. In addition, WEEE chemicals induced inflammatory responses in resting macrophages and altered inflammatory responses in lipopolysaccharide-primed macrophages. Furthermore, WEEE chemicals activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, indicating oxidative stress, and the aryl hydrocarbon receptor (AhR). Endocrine disruption was also observed through the activation of estrogenic receptor-α (ER-α) and the induction of anti-androgenic activity. The findings show that WEEE plastic-associated chemicals exert effects in multiple subcellular sites, via different receptors and mechanisms. Thus, an integrated approach employing both chemical and toxicological methods is essential for comprehensive assessment of the toxicity mechanisms and cumulative chemical burden of WEEE plastic-associated chemicals.

Two sides of the same coin: Weathering differences of plastic fragments in coastal environments around the globe

Plastic debris in coastal environments usually undergoes weathering due to various environmental conditions. However, the weathering effects on exposed and shaded sides of the same plastics are underexplored. In this study, 1573 plastic fragments were collected from 15 coastal sites worldwide between December 2021 and December 2022, and weathering experiments were conducted outdoors. The field investigation showed significant two-sided weathering differences of plastic fragments. The weathering morphology included biota, cracks, delamination, discoloration, etc. The weathering degree was assessed with three metrics, i.e., line density (0-58 mm/mm2), surface loss (0-92 %), and texture index (0-2). The 3D magnitudes of these three metrics revealed the two-sided weathering differences of plastic fragments. Specifically, 43 % of the samples had magnitudes > 5, indicating significant differences. Outdoor simulations suggested that sun-exposed sides developed more cracks, pores, and bubbles, while shaded sides remained smoother. After 12 months, the line density increased from 2.85 to 9.23 mm/mm² for polyethylene (PE) and 4.16-8.47 mm/mm² for polypropylene (PP) (p < 0.05). The carbonyl index increased from 0.50 to 1.70 (PE), from 0.18 to 1.10 (PP), and from 0.45 to 1.57 (polyvinyl chloride). This increase indicated oxidative degradation on sun-exposed sides. Our results highlighted the uneven degree of weathering on both sides of the same plastic fragment due to different environmental factors. The study provided critical insights for creating more accurate models to predict plastic degradation, which will help inform global strategies to reduce plastic pollution.

Microplastic induces microbial nitrogen limitation further alters microbial nitrogentransformation: Insights from metagenomic analysis

Microplastic has a significant impact on soil microbial communities, which play crucial roles in soil nitrogen (N) cycles. However, there is a limited understanding of their influences on genes associated with the entire N cycling pathways. Through a 120-day soil incubation using conventional (PE and PET) and biodegradable microplastics (PLA and PBAT), coupled with 16S rRNA and metagenomic sequencing, we investigated the responses of N-cycling genes to microplastics in two contrasting soils (i.e. black soil and loess soil). We found that biodegradable microplastics strongly altered microbial N functional profiles, and enhanced the abundance of numerous key genes involved in N fixation, organic N mineralization, N reduction, and denitrification. Furthermore, biodegradable microplastics significantly decreased net N mineralization (Nm) compared to control and conventional microplastic treatments, suggesting microbial N immobilization outweighed N mineralization. Analysis of the function-taxon bipartite network showed that the Nm was well predicted for the abundances and diversity of bacteria within specific modules, with Nm decreasing, the abundances of specific taxa in a given network modules increasing. These results indicated that biodegradable microplastics act as a carbon source to select specific taxa involved in enhancing N bioavailability (e.g., N fixation and organic N mineralization) to meet microbial N demand, which in turn filtered the bacterial community (decreased diversity but increased abundances) and gradually formed specific function-taxon modules. Comparing the two soils, microbes in the less fertile alkaline loess soil were more sensitive to biodegradable microplastics than those in the nutrient-rich acid black soil. Our study indicated that increasing usage of biodegradable plastics in the future may lead to accelerated soil microbial N limitation and transformation.

Oral exposure to nanoplastics altered lipid profiles in mouse intestine

The wide uses of plastics lead to nanoplastic exposure in reality. Previous studies reported that micro- and nano-plastics (MNPs) disrupted metabolism, but few studies investigated lipid profile changes. Hereby, we exposed mice to vehicles (control), 0.05 or 0.5 mg/kg 20 or 100 nm nanoplastics via gavage, once a day, for 14 days. Albeit no obvious tissue damage, lipidomics data revealed 76 up-regulated and 29 down-regulated lipid molecules in mouse intestines. Further analysis revealed that a number of up-regulated lipid molecules belong to glycerophospholipid (GP). Among GP, we noticed an up-regulation of 9 phosphatidylserine (PS) molecules, and we further verified the presence of autophagosomes and co-localization of typical autophagic lipolysis proteins in intestinal sections, as well as decreased lysosomal associated protein 2 (LAMP2) and increased adipose triglyceride lipase (ATGL) in intestinal homogenates, indicating perturbed autophagic pathway. The exposure also up-regulated 9 phosphatidylinositol (PI) molecules, and we verified a significant decrease of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), indicating altered PI3K-signaling pathway. Besides GP, nanoplastics also significantly up-regulated some sphingolipids (SP), such as ceramide (Cer), and some sterol lipids, such as cholesterol derivatives. Combined, these results suggested that oral exposure to nanoplastics altered lipid profiles and related signaling pathway in mouse intestines.

Using artificial intelligence tools for data quality evaluation in the context of microplastic human health risk assessments

Concerns about the negative impacts of microplastics on human health are increasing in society, while exposure and risk assessments require high-quality, reliable data. Although quality assurance and -control (QA/QC) frameworks exist to evaluate the reliability of data for these purposes, manually assessing studies is too time-consuming and prone to inconsistencies due to semantic ambiguities and evaluator bias. The rapid growth of microplastic studies makes manually screening relevant data practically unfeasible. This study explores the potential of artificial intelligence (AI), specifically large language models (LLMs) such as OpenAI's ChatGPT and Google's Gemini, to streamline and standardize the QA/QC screening of data in microplastics research. We developed specific prompts based on previously published QA/QC criteria for the analysis of microplastics in drinking water and its sources, and used these to instruct AI tools to evaluate 73 studies published between 2011 and 2024. Our approach demonstrated the effectiveness of AI in extracting relevant information, interpreting the reliability of studies, and replicating human assessments. The findings indicate that AI-assisted assessments show promise in improving speed, consistency and applicability in QA/QC tasks, as well as in ranking studies or datasets based on their suitability for exposure and risk assessments. This groundbreaking application of LLMs in the environmental sciences suggests that AI can play a vital role in harmonizing microplastics risk assessments within regulatory frameworks and demonstrates how to meet the demands of an increasingly data-intensive application domain.

Exposure to nanoplastics exacerbates light pollution hazards to mammalian

Environmental light pollution adversely affects brain function, disturbing circadian rhythms and negatively impacting human health. Nanoplastics (NPs) pollution is pervasive in the human environment, and their minuscule size facilitates entry into the body, particularly invading brain and compromising its functionality. However, whether NPs infiltrate rhythm-regulated brain regions and disrupt circadian rhythms in organisms remains unclear. Our study demonstrates that exposure to NPs in mice perturbs normal circadian rhythms. Specifically, NPs invade the suprachiasmatic nucleus (SCN), affecting the circadian clock genes network and altering the regular oscillations of core clock genes. Exposure to NPs renders the intrinsic rhythms more susceptible to disruption by light pollution, resulting in more pronounced disorder to metabolism, immune regulation, and brain function. This work is the first to investigate the combined effects of ambient light pollution and NPs pollution on mammalian health, and our findings suggest that NPs amplify the health impacts of light pollution. These findings also highlight that efforts to mitigate human health risks from environmental pollutants should begin to consider the synergistic effects of various classes of pollutants.

Airborne microplastic contamination and health risks in Greater Cairo, Egypt

Air pollution by microplastics (MPs) is an increasingly concerning environmental issue, but the presence of MPs in the atmosphere and its potential health risks has not been studied in Greater Cairo. The sites were therefore selected during the winter season from the north to the south of the Cairo metropolitan area, representing urban and residential/industrial areas in terms of population, traffic, and industrial pressure. This was achieved through a combination of quantitative MP detection, mathematical modeling, and a risk assessment approach based on total suspended particulate matter (TSP) at these sites. The TSP concentration was investigated in the air and associated MP particles. The highest MP values were found at the study sites with higher population and more traffic than at lower locations. The spatial distribution of site concentrations was from high to low. Helwan site (87 particles/m3) had the most MP, followed by Dokki (69 particles/m3) and Nasr City (60 particles/m3), and El-Nozha had the least MP during the investigation (30 particles/m3). The morphology, composition, and size of these MPs in the samples were determined by scanning electron microscopy (SEM) and gas chromatography-mass spectrometry (GC-MS). Various MP forms have been identified in these sites, including fibers, fragments, films, and pellets, with fragments being the most common. Three different MP polymers (PE, PP, and PS) were identified. The potential health risks posed by airborne MPs cannot be ignored when exposed to outdoor airborne substances at maximum annual levels. This study confirms the widespread existence of the inhaled MP in the air and provides a solid basis for future studies aimed at understanding real-world conditions of inhalation exposure to MP.

The coexistence characteristics of microplastics and heavy metals in rhizomes of traditional Chinese medicine in mulch planting area

Rhizomatous traditional Chinese medicines (RTCMs) are widely crushed into powder and swallowed directly as medicine and food or health products to treat various diseases; however, they may contain toxic microplastics (MPs) and heavy metals. Currently, there are no reports on the detection of MPs and MP-heavy metal synergies in RTCMs. In this study, we selected eight representative RTCMs to investigate the abundance, types, sizes, and polymers of MP and heavy metals and to assess the level of contamination of MPs and synergies between MPs and heavy metals in RTCMs. The abundance of MPs in different RTCM ranged from 20.83 to 43.65 items/g. The dominant type was fragment (95.43%), and the dominant particle size was < 0.5 mm (73.72%) in MPs. Polyurethane (PU) (29.21%) and acrylics (ACR 13.53%) were the dominant polymers of MP. MP polymers showed obvious correlations with type and particle size: PU was enriched in 0-50-mm and 100-300-mm fragments, whereas ethylene vinyl acetate and ACR were enriched in 0-30-mm fibers. The heavy metals arsenic (As), lead (Pb), and chromium (Cr) were found to be more susceptible to synergistic contamination with MPs in RTCMs compared to other heavy metals. The estimated daily intake (EDI) of the MPs and heavy metals for RG (Rehmannia glutinosa) and RAY (Rhizoma atractylodis) were higher than others. The results showed that MP pollution is common in RTCMs and carries the potential risk of heavy metal or MP poisoning in humans who consume RTCMs.

From food-to-human microplastics and nanoplastics exposure and health effects: A review on food, animal and human monitoring data

This review figures out the overall status on the presence of microplastics (MPs) and nanoplastics (NPs) in food and their bioaccumulation in animal and human tissues, providing critical insights into possible human health impacts. Data are discussed on both in-vivo and ex-vivo animal and human studies, and the role of physicochemical properties in determining the biological fate and toxicological effects of MPs and NPs. Particular attention is given to dietary exposure assessments, specifically evaluating daily intake through the consumption of contaminated food items. The current limitations in the body of knowledge and some considerations for future assessments are also reported. Overall, there is a pressing need to establish more robust biomarker research and develop standardized methodologies, for a better understanding of MPs and NPs fate and associated effects in more realistic scenarios for their safe consumption. The review underscores the importance of integrating the human biomonitoring into monitoring programs and interdisciplinary research to ultimately inform on MPs and NPs real burden in the human body.

Impact of artificial sunlight aging on the respiratory effects of polyethylene terephthalate microplastics through degradation-mediated terephthalic acid release in male mice

Microplastics are ubiquitous in the atmosphere, leading to human exposure through inhalation. Airborne microplastics undergo degradation due to sunlight irradiation, yet the respiratory risks associated with degraded microplastics remain poorly understood. In this study, we investigated the respiratory effects of polyethylene terephthalate (PET) degraded by artificial sunlight and created a transport and degradation model of PET for risk assessment. PET fibers were cut and subjected to artificial sunlight irradiation. Mice exposed to aged PET showed increased airway resistance induced by methacholine (MCh) inhalation, along with lung inflammation and neutrophil infiltration. Terephthalic acid (TPA) was continuously released from PET aged by artificial sunlight. Exposure to TPA also caused lung inflammation and enhanced airway resistance induced by MCh in mice. These findings indicate that aged PET can cause respiratory impairment via TPA release. A simple transport and degradation model was developed to quantitatively relate the abundance of aged PET produced in this study (i.e. 4,000 × 96 W m-2 h) and aged fractions of PET that can be generated in the atmosphere. Our results suggested 10% to 60% of PET was degraded as that produced in this study over sunny regions in summer, whereas only lower than 1% in high-latitude cities in Europe in winter. This study demonstrates the importance of considering the abundance of aged PET and further development of a transport and degradation model of PET to assess the risk of degraded PET in the atmosphere.

Factors affecting microplastic pollution of sandboxes in urban residential areas: Simple methodology for quality control in the context of potential exposure assessment for children

Occurrence of microplastics in the environment is well studied, but our knowledge of their distribution in specific locations, such as the sandboxes, which are integral parts of popular playgrounds for children, is limited. Pioneering research on the factors affecting the microplastic pollution of sandboxes in urban residential areas was conducted within three estates in Kielce, Poland. Sand samples (Σ27) were collected from nine sandboxes and examined for the presence of microplastics, using a simple quality control methodology proposed by the authors. Microplastics were found in each sample and their contents ranged from 60 to 5,540 items/kg of sand. Fragments and fibers were the most prevalent types of microplastics in the samples. They contributed to approximately 95% of all microplastics found. Transparent fibers were the most abundant among fibers (63%) and red particles (57%) among fragments. A strong, positive, and significant correlation (rSpearman = 0.90) was found between the number of microplastic items and the location of sandboxes (above sea level). There was no correlation between the population density of the estates (rSpearman  =  0.03), the distance of the estates from the center (rSpearman  =  0.02), and the distance of the estates from main roads (rSpearman  =  0.43). Considering that sandboxes can be a potential source of microplastics for children, and assuming that sand ingestion by children is similar to the estimated daily soil ingestion rate, our results indicate that the number of microplastics ingested could be 1,106. Inhalation, dermal transport, and ingestion of microplastic particles from sandboxes pose a potential threat to children's health. However, more research is needed to better understand the health risks associated with this source of microplastics.

Long-term nanoplastics exposure contributes to impaired steroidogenesis by disrupting the hypothalamic-testis axis: Evidence from integrated transcriptome and metabolome analysis

Cumulative evidence suggested that nanoplastics (NPs) cause male toxicity, but the mechanisms of which are still misty. Steroidogenesis is a key biological event that responsible for maintaining reproductive health. However, whether dysregulated steroidogenesis is involved in NPs-induced impaired male reproductive function and the underlying mechanism remains unclear. In our study, Balb/c mice were continuously exposed to pristine-NPs or NH2-NPs for 12 weeks, spanning the puberty and adult stage. Upon the long-term NPs treatment, the hypothalamus and testis were subjected to transcriptome and metabolome analysis. And the results demonstrated that both primitive-NPs and NH2-NPs resulted in impaired spermatogenesis and steroidogenesis, as evidenced by a significant reduction in sperm quality, testosterone, FSH, and LH. The expression of genes involved in hypothalamic-pituitary-testis (HPT) axis, such as Kiss-1 and Cyp17a1 that encoded the key steroid hormone synthetase, was also diminished. Furthermore, the phosphatidylcholine and pantothenic acid that mainly enriched in glycerophospholipid metabolism were significantly reduced in the testis. Comprehensive analysis of the transcriptome and metabolome indicated that down-regulated Cyp17a1 was associated with decreased metabolites phosphatidylcholine and pantothenic acid. Overall, we speculate that the disturbed HPT axis induced by long-term NPs contributes to disordered glycerophospholipid metabolism and subsequently impaired steroidogenesis. Our findings deepen the understanding of the action of the mechanism responsible for NPs-induced male reproductive toxicology.

Assessing Hydrocyclone System's Efficiency in Water-Borne Microplastics Capture Using Online Microscopy Sensors

Plastic pollution has been a global concern. Microplastics are often referred to as plastic particulates whose sizes are within the range of 1 μm to 5 mm. To cost-effectively capture these tiny microplastics from open environments, such as from the air or aquatic/marine systems, is far from trivial. Not only is some innovative capturing technology demanded, but some online monitoring solutions are often requested as well to assess the capturing effectiveness and efficiency, as well as provide some feedback information to the control system to adapt to varying operating conditions. Inspired by the de-oiling treatment of the produced water in offshore oil & gas production, this paper explores the potential to apply the hydrocyclone technology to cost-effectively handle the water-borne microplastics, and its effectiveness is demonstrated based on reliably calibrated online microscopy measurements subject to artificial polyethylene particulates added to the water stream. The experimental work is carried out using a commercial de-oiling hydrocyclone system and a set of commercial optical microscopy sensors. A statistic-based calibration method is firstly proposed for the deployed microscopy sensors to select the best calibration parameters. Afterwards these sensors are installed at the inlet and water-outlet of the hydrocyclone system via a side-stream sampling mechanism to assess this system's (microplastics) separation efficiency subject to dynamical operating conditions, which are mimicked by manipulating its underflow and overflow control valves via PI-controlled loops. The separation efficiencies are calculated based on these volume concentration measurements and compared between the case with (statistically) optimal calibration parameters and the case with a set of non-optimal parameters. The best separation efficiency of 87.76% under the optimal calibration parameters is observed under a specific operating condition. The obtained result shows a promising potential to use these separation and sensing systems to cost-effectively handle aquatic microplastics collection, though it also indicates that a further higher efficiency could be achieved by some (microplastics) dedicated cyclone design combined with a dedicated process control system, and this is one part of our ongoing research work.

Impact of microplastics on the human digestive system: From basic to clinical

As a new type of pollutant, the harm caused by microplastics (MPs) to organisms has been the research focus. Recently, the proportion of MPs ingested through the digestive tract has gradually increased with the popularity of fast-food products, such as takeout. The damage to the digestive system has attracted increasing attention. We reviewed the literature regarding toxicity of MPs and observed that they have different effects on multiple organs of the digestive system. The mechanism may be related to the toxic effects of MPs themselves, interactions with various substances in the biological body, and participation in various signaling pathways to induce adverse reactions as a carrier of toxins to increase the time and amount of body absorption. Based on the toxicity mechanism of MPs, we propose specific suggestions to provide a theoretical reference for the government and relevant departments.

Environmental impact of microplastic emissions from wastewater treatment plant through life cycle assessment

This study aimed to quantify the environmental impact of microplastic (MP) emissions from wastewater treatment plants (WWTPs) using life cycle assessment (LCA). The investigation comprehensively evaluated the contribution of MPs to overall WWTP midpoint and endpoint impacts, with a detailed analysis of the influence of particle size, shape, polymer type, and the environmental costs and benefits of individual wastewater treatment processes on MP removal. The LCA model was developed using SimaPro software, with impact assessments conducted via the USEtox framework and the IMPACT World+ methodology. Results showed that at the midpoint level, MPs accounted for 1.24E+05 CTUe (94 % of the total plant impact), representing the potential harm to aquatic species per cubic meter of discharged wastewater-surpassing the impacts of other contaminants (e.g., heavy metals, nutrients) by at least two orders of magnitude. At the endpoint level, the damage of 8.39E-02 PDF·m2·yr (1.7 % of the total) indicated the potential loss of species diversity, comparable to other pollutant contributions. Polyethylene, polystyrene, and polypropylene were identified as the most impactful polymer types. In terms of environmental costs and benefits, secondary, tertiary, and primary treatments demonstrated decreasing environmental benefits, directly correlated with their respective MP removal efficiencies. These findings underscore the critical role of MP emissions in WWTP life cycle inventories and highlight the urgent need for targeted environmental policies and advanced treatment technologies to address MP contamination in both natural and engineered aquatic systems.

Co-Existing Nanoplastics Further Exacerbates the Effects of Triclosan on the Physiological Functions of Human Serum Albumin

The potential health risks posed by the coexistence of nanoplastics (NPs) and triclosan (TCS) have garnered significant attention. However, the effects and underlying mechanisms of NPs and TCS on key functional proteins at the molecular level remain poorly understood. This study reports the effect of polystyrene nanoplastics (PSNPs) on the binding of TCS to human serum albumin (HSA) using multispectral methods and molecular simulation systems. The experimental results show that TCS significantly inhibits HSA esterase activity, with exacerbating inhibition in the presence of PSNPs, which is attributed to the alteration of HSA conformation and microenvironment of the amino acid residues induced by PSNPs. Molecular docking and site marker competitive studies indicate that TCS predominantly binds to site I of subdomain Sudlow II and the presence of PSNPs does not affect the binding sites. Spectra analyses indicate that the quenching mechanism between TCS and HSA belongs to the static quenching type and the presence of PSNPs does not change the fluorescence quenching type. The HSA fluorescence quenching and the conformational alterations induced by TCS are further enhanced in the presence of PSNPs, indicating that PSNPs enhance the binding of TCS to HSA by making TCS more accessible to the binding sites. This study provides valuable information about the toxicity of PSNPs and TCS in case of co-exposure.

Polystyrene nanoplastics promote the blood-brain barrier dysfunction through autophagy pathway and excessive erythrophagocytosis

There is increasing concern regarding the risks posed by plastics to human health. Nano-sized plastics enter the body through various exposure routes. Although nano-sized particles circulate through the bloodstream and access the blood-brain barrier (BBB), the harmful impacts of nano-sized plastics on BBB function including endothelial cells are not well known. In this study, polystyrene nanoplastics (PS-NP) resulted in hyperpermeability and damaged tight junction proteins in brain endothelial cells. We identified that PS-NP increased intracellular iron levels by inhibiting the autophagy pathway in brain endothelial cells. Our study showed that dysregulated autophagy pathways led to increased BBB permeability induced by PS-NP treatment. In addition, PS-NP caused excessive erythrophagocytosis in brain endothelial cells via damaged red blood cells. PS-NP-treated RBCs (NP-RBC) induced the BBB dysfunction and increased intracellular iron levels and ferroptosis in brain endothelial cells. We provide novel insights into the potential risks of nano-sized plastics in BBB function by interaction between cells as well as direct exposure. Our study will help to understand the cardiovascular toxicity of nano-sized plastics.

A smartphone label-free and automated thermo-analytical method based on image analysis to detect microplastics

Microplastics (MPs) are in some ways the expected product of man-made plastics that are considered as a pollutant ubiquitous in the environment. This is particularly notorious in continental waters, along coastlines, and especially in the North Pacific Gyre, sometimes called the Pacific Garbage Patch. Even now, there is growing concern that MPs can harm wildlife, enter the food chain, and end up in the human body. Therefore, the development of new, simpler and easily automated analytical systems is needed to assess the extent of MPs contamination in the environment. In this work, we present a low-cost analytical method capable of identifying, counting, and sizing MPs and differentiating them from non-plastic particles in less than 5 min after performing image-based analysis during a heating ramp between 25 and 220 °C. Using a smartphone and its camera and a dedicated algorithm, semi-crystalline and amorphous MPs such as polyethylene, polypropylene and polystyrene were efficiently identified by determining whether they melt or change size. The method was tested on spiked soil and sand samples as well as on real samples with successful results. A large number of particles can be analyzed simultaneously using an algorithm that eliminates the need for manual operations. The method is presented to be used as the first necessary step to investigate the level of threat (if any) of this new ubiquitous presence.

Mixtures of polystyrene micro and nanoplastics affects fat and glucose metabolism in 3T3-L1 adipocytes and zebrafish larvae

Microplastics (MPs) and nanoplastics (NPs) are pervasive pollutants that pose a hazard to human health. Although most previous studies have investigated the effects of MPs and NPs on digestion, oxidative stress, and inflammation in diverse models, the combined effect of plastic mixtures (PM) containing MPs and NPs on obesity and type 2 diabetes mellitus (T2DM) remains unknown. The hypothesis of our study is to verify the association between PM exposure and clinical features of metabolic diseases such as lipogenesis and insulin resistance. Therefore, we investigated the effects of PM on fat and glucose metabolism in 3T3-L1 cells and high-fat diet (HFD)-induced zebrafish larvae. PM exposure increased cell viability, differentiation, adipogenesis (PPARγ and C/EBPα), and lipogenesis (FAS and SREBP-1c), while it decreased glucose uptake and inhibited insulin signal (IRS1, PI3K, AKT, and GLUT4) expression 3T3-L1 cells. In zebrafish larvae, PM mainly bioaccumulated in the intestine and pancreatic tissue, reducing glucose uptake and increasing body weight and blood glucose compared to controls. Moreover, PM significantly increased adipogenic differentiation (PPARγ) and synthesis (FASN and FABP), proinflammatory cytokines (TNF-α and IL-6), and gluconeogenesis (PCK1 and G6Pase). Conversely, energy and fat metabolism (AMPKα and adiponectin), insulin production (INSα), signaling pathway (IRS1, AKT, and GLUT2), and anti-inflammatory cytokines (IL-10 and IL-4) were suppressed. Overall, this study sheds light on the mechanisms responsible for the detrimental effects of PM exposure on fat and glucose metabolism, providing insights into metabolic disorders, like type 2 diabetes, in both in vitro and in vivo models.

Medical exposure to micro(nano)plastics: An exposure pathway with potentially significant harm to human health that should not be overlooked

Micro(nano)plastics (MNPs) are an emerging type of contaminants that are widely present in the environments that people live in. MNPs can enter the human body in a variety of pathways, but the three main ones are through dietary intake, air inhalation, and skin contact. However, it has been discovered that medical plastics used in medical activities also pose potential risks to MNPs exposure as exposure pathways are continuously refined and clarified. Unfortunately, there is currently insufficient study on the exposure of medical plastics and MNPs, and exposure risks and potential health problems are frequently overlooked. This study aimed to close this research gap by searching the databases of China National Knowledge Infrastructure (CNKI), PubMed, and Web of Science for relevant literature. It then filtered out publications that contained information relevant to keywords such as micro(nano)plastics, medical plastics, exposure pathways, and human health in order to do analysis and summary. We discovered that medical plastics are a high-risk source of direct MNPs exposure to the human body, and this exposure could pose a potential harm to human health. Because of the potential harm to human health, this work presents the medical exposure of MNPs for the first time and calls for more research and attention on this vital area.

Pollution status of microplastics in the sediments of warm monomictic Dal lake, India: Abundance, composition, and risk assessment

This report presents the first investigation of microplastic (MP) contamination in the shoreline sediments of Dal Lake, Jammu and Kashmir, India. The MP concentrations ranged from 503 to 3154 MP/kg, with a notable seasonal variation. The highest concentrations of microplastics occurred in the Spring, ranging from 467 to 3445 MP/kg. Microplastics were identified using optical microscopy, Fourier Transform Infrared spectroscopy, and thermogravimetric analysis. Polymer analysis revealed that the Gagribal basin was contaminated with polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), and polyethylene terephthalate (PET). In contrast, the Nigeen basin mainly comprises PE, PP, and PS. The significantly elevated Polymer Hazard Index (PHI) values, exceeding 1000 in the Gagribal basin, were attributed to the presence of PVC. Sediment quality was assessed using Pollution Load Index (PLI), Potential Ecological Risk Index (PERI), and PHI. Health risk metrics, such as estimated daily intake (EDI) and microplastic carcinogenic risks (MPCR), were also evaluated. There is a positive correlation between microplastic abundance and total organic carbon (TOC), total phosphorus (TP), and total nitrogen (TN). The Nigeen basin, characterized by a higher proportion of less hazardous polymers like PP, exhibited greater TOC levels due to enhanced microbial degradation of microplastics. Conversely, the Gagribal basin, with its higher presence of toxic polymers like PVC, had lower TOC levels, likely due to these compounds' inhibition of microbial activity. This study provides crucial insight into the spatial distribution and ecological impact of MPs in Dal Lake, setting the stage for future research on their effects on aquatic ecosystems.

Airborne micro- and nanoplastics: emerging causes of respiratory diseases

Airborne micro- and nanoplastics (AMNPs) are ubiquitously present in human living environments and pose significant threats to respiratory health. Currently, much research has been conducted on the relationship between micro- and nanoplastics (MNPs) and cardiovascular and gastrointestinal diseases, yet there is a clear lack of understanding regarding the link between AMNPs and respiratory diseases. Therefore, it is imperative to explore the relationship between the two. Recent extensive studies by numerous scholars on the characteristics of AMNPs and their relationship with respiratory diseases have robustly demonstrated that AMNPs from various sources significantly influence the onset and progression of respiratory conditions. Thus, investigating the intrinsic mechanisms involved and finding necessary preventive and therapeutic measures are crucial. In this review, we primarily describe the fundamental characteristics of AMNPs, their impact on the respiratory system, and the intrinsic toxic mechanisms that facilitate disease development. It is hoped that this article will provide new insights for further research and contribute to the advancement of human health.

MRI-based microplastic tracking in vivo and targeted toxicity analysis

Microplastics (MPs) as an emerging pollutant have raised significant concerns in environmental health. However, elucidating the distribution of MPs in living organisms remains challenging due to their trace residue and tough detection problems. In this study, a novel magnetic resonance imaging (MRI)-based tracking method was employed to monitor functionalized MPs biodistribution in vivo. Our results identified that the liver is the primary accumulation site of polystyrene microplastics (PS-MPs) in biological systems through continuous in vivo monitoring spanning 21 days. Biochemical tests were performed to assess the toxicological effects of functionalized MPs on the liver tissue, revealing hepatocyte death, inflammatory cell infiltration, and alterations in alkaline phosphatase levels. Notably, positively charged MPs exhibited more severe effects. A combined metabolomics-proteomics analysis further revealed that PS-MPs interfered with hepatic metabolic pathways, particularly bile secretion and ABC transporters. Overall, this study effectively assessed the distribution of functionalized MPs in vivo utilizing MRI technology, validated toxicity in targeted organ, and conducted an in-depth study on underlying biotoxicity mechanism. These findings offer crucial scientific insights into the potential impact of MPs in the actual environment on human health.

Towards a risk assessment framework for micro- and nanoplastic particles for human health

BACKGROUND

Human exposure to micro- and nanoplastic particles (MNPs) is inevitable but human health risk assessment remains challenging for several reasons. MNPs are complex mixtures of particles derived from different polymer types, which may contain plenty of additives and/or contaminants. MNPs cover broad size distributions and often have irregular shapes and morphologies. Moreover, several of their properties change over time due to aging/ weathering. Case-by-case assessment of each MNP type does not seem feasible, more straightforward methodologies are needed. However, conceptual approaches for human health risk assessment are rare, reliable methods for exposure and hazard assessment are largely missing, and meaningful data is scarce.

METHODS

Here we reviewed the state-of-the-art concerning risk assessment of chemicals with a specific focus on polymers as well as on (nano-)particles and fibres. For this purpose, we broadly screened relevant knowledge including guidance documents, standards, scientific publications, publicly available reports. We identified several suitable concepts such as: (i) polymers of low concern (PLC), (ii) poorly soluble low toxicity particles (PSLT) and (iii) fibre pathogenicity paradigm (FPP). We also aimed to identify promising methods, which may serve as a reasonable starting point for a test strategy.

RESULTS AND CONCLUSION

Here, we propose a state-of-the-art modular risk assessment framework for MNPs, focusing primarily on inhalation as a key exposure route for humans that combines several integrated approaches to testing and assessment (IATAs). The framework starts with basic physicochemical characterisation (step 1), followed by assessing the potential for inhalative exposure (step 2) and includes several modules for toxicological assessment (step 3). We provide guidance on how to apply the framework and suggest suitable methods for characterization of physicochemical properties, exposure and hazard assessment. We put special emphasis on new approach methodologies (NAMs) and included grouping, where adequate. The framework has been improved in several iterative cycles by taking into account expert feedback and is currently being tested in several case studies. Overall, it can be regarded as an important step forward to tackle human health risk assessment.

The Global Spread of Microplastics: Contamination in Mussels, Clams, and Crustaceans from World Markets

Analysis of microplastic (MP) occurrence in commercially relevant species is a prerequisite for food risk assessment. Using a standardized methodology, we aimed to investigate MP contamination in point-of-sale clams, mussels, and Crustacea shellfish collected from various markets (Belgium, Croatia, Serbia, and South Korea). An improved digestion protocol yielded ≥ 99.8% digestion efficiency for all species analyzed. In a total of 190 samples analyzed individually by microFTIR, MPs were identified in 43.68% of the samples with less than 1 MP/individual average (0-4 MP/individual, 0-1.35 MPs/g tissue). Significant differences between species were observed when considering samples contaminated with MPs, with Crustacea shellfish having the lowest MPs/g of edible tissue. Polystyrene, polypropylene, and polyethylene were dominant MPs found in clams and mussels, while polyamide, polyethylene terephthalate, and polyvinyl chloride were the most abundant in Crustacea shellfish. Our data do not support the bioaccumulation or biomagnification of MPs with the size of the animal in the shellfish group. MP contamination is more strongly associated with the type of shellfish than with the geographical origin of the market.

Microplastics and Trash Cleaning and Harmonization (MaTCH): Semantic Data Ingestion and Harmonization Using Artificial Intelligence

With the rapid expansion of microplastic research and reliance on semantic descriptors, there is an increasing need for plastic pollution data harmonization. Data standards have been developed but are seldom implemented across research sectors, geographic regions, environmental media, or size classes of plastic pollution. Harmonization of existing data is currently hindered by increasingly large datasets using thousands of different categorical variable descriptors, as well as various metrics used to describe particle abundance and differing size ranges studied across groups. For this study, we used manually developed relational databases to build an algorithm utilizing artificial intelligence capable of automatically curating harmonized, more usable datasets describing micro to macro plastic pollution in the environment. The study algorithm MaTCH (microplastics and trash cleaning and harmonization) can harmonize datasets with different formats, nomenclature, methods, and measured particle characteristics with an accuracy of 71-94% when matching semantically. All other non-semantic corrections are reported within a 95% confidence interval and with model uncertainty. All steps of the algorithm are integrated in an open-source software tool for the benefit of the scientific community and ease of integration for all plastic pollution data.

Local and systemic effects of microplastic particles through cell damage, release of chemicals and drugs, dysbiosis, and interference with the absorption of nutrients

Microplastic particles (MPs) have been detected in a variety of environmental samples, including soil, water, food, and air. Cellular studies and animal exposures reported that exposure to MPs composed of different polymers might result in adverse effects at the portal of entry (local) or throughout the body (systemic). The most relevant routes of particle uptake into the body are oral and respiratory exposure. This review describes the various processes that may contribute to the adverse effects of MPs. Only MPs up to 5 µm were found to cross epithelial barriers to a significant extent. However, MPs may also exert a detrimental impact on human health by acting at the epithelial barrier and within the lumen of the orogastrointestinal and respiratory tract. The potential for adverse effects on human health resulting from the leaching, sorption, and desorption of chemicals, as well as the impact of MPs on nutritional status and dysbiosis, are reviewed. In vitro models are suggested as a means of (1) assessing permeation, (2) determining adverse effects on cells of the epithelial barrier, (3) examining influence of digestive fluids on leaching, desorption, and particle properties, and (4) role of microbiota-epithelial cell interactions. The contribution of these mechanisms to human health depends upon exposure levels, which unfortunately have been estimated very differently.

Rapid Generation of Microplastics and Plastic-Derived Dissolved Organic Matter from Food Packaging Films under Simulated Aging Conditions

In this study, we show that low-density polyethylene films, a prevalent choice for food packaging in everyday life, generated high numbers of microplastics (MPs) and hundreds to thousands of plastic-derived dissolved organic matter (DOM) substances under simulated food preparation and storage conditions. Specifically, the plastic film generated 66-2034 MPs/cm2 (size range 10-5000 μm) under simulated aging conditions involving microwave irradiation, heating, steaming, UV irradiation, refrigeration, freezing, and freeze-thaw cycling alongside contact with water, which were 15-453 times that of the control (plastic film immersed in water without aging). We also noticed a substantial release of plastic-derived DOM. Using ultrahigh-resolution mass spectrometry, we identified 321-1414 analytes with molecular weights ranging from 200 to 800 Da, representing plastic-derived DOM containing C, H, and O. The DOM substances included both degradation products of polyethylene (including oxidized forms of oligomers) and toxic plastic additives. Interestingly, although no apparent oxidation was observed for the plastic film under aging conditions, plastic-derived DOM was more oxidized (average O/C increased by 27-46%) following aging with a higher state of carbon saturation and higher polarity. These findings highlight the future need to assess risks associated with MP and DOM release from plastic wraps.

Microplastics in the Human Body: Exposure, Detection, and Risk of Carcinogenesis: A State-of-the-Art Review

Background: Humans cannot avoid plastic exposure due to its ubiquitous presence in the natural environment. The waste generated is poorly biodegradable and exists in the form of MPs, which can enter the human body primarily through the digestive tract, respiratory tract, or damaged skin and accumulate in various tissues by crossing biological membrane barriers. There is an increasing amount of research on the health effects of MPs. Most literature reports focus on the impact of plastics on the respiratory, digestive, reproductive, hormonal, nervous, and immune systems, as well as the metabolic effects of MPs accumulation leading to epidemics of obesity, diabetes, hypertension, and non-alcoholic fatty liver disease. MPs, as xenobiotics, undergo ADMET processes in the body, i.e., absorption, distribution, metabolism, and excretion, which are not fully understood. Of particular concern are the carcinogenic chemicals added to plastics during manufacturing or adsorbed from the environment, such as chlorinated paraffins, phthalates, phenols, and bisphenols, which can be released when absorbed by the body. The continuous increase in NMP exposure has accelerated during the SARS-CoV-2 pandemic when there was a need to use single-use plastic products in daily life. Therefore, there is an urgent need to diagnose problems related to the health effects of MP exposure and detection. Methods: We collected eligible publications mainly from PubMed published between 2017 and 2024. Results: In this review, we summarize the current knowledge on potential sources and routes of exposure, translocation pathways, identification methods, and carcinogenic potential confirmed by in vitro and in vivo studies. Additionally, we discuss the limitations of studies such as contamination during sample preparation and instrumental limitations constraints affecting imaging quality and MPs detection sensitivity. Conclusions: The assessment of MP content in samples should be performed according to the appropriate procedure and analytical technique to ensure Quality and Control (QA/QC). It was confirmed that MPs can be absorbed and accumulated in distant tissues, leading to an inflammatory response and initiation of signaling pathways responsible for malignant transformation.

Biological exposure to microplastics and nanoplastics and plastic additives: impairment of glycolipid metabolism and adverse effects on metabolic diseases

Microplastics and nanoplastics (M-NPs) are widespread pollutants in the environment, posing growing risks to human health and garnering increasing concern from researchers. Due to their small particle size, ease of adsorption, and resistance to degradation, M-NPs can retain and migrate in the environment for long-term periods. Upon entering organisms, M-NPs have been reported to cause inflammation and oxidative stress and result in abnormalities in glycolipid metabolism. Furthermore, research suggests that exposure to M-NPs may act as a causative agent for metabolic and cardiovascular diseases such as diabetes, obesity, and atherosclerosis. This paper aims to review the consequences of exposure to M-NPs on animal and cellular glycolipid metabolism and discusses the disruption of gut microbial homeostasis and the subsequent emergence of insulin resistance. PPAR signaling pathway activation after exposure to M-NPs was found to lead to increased hepatic fat accumulation and impaired lipid metabolism. Additionally, the paper highlights how M-NPs exacerbate the progression of obesity and diabetes in patients, induce damage to vascular endothelial cells, trigger oxidative stress, and contribute to the development of atherosclerosis. Despite the growing concern, the toxicity and molecular mechanism of M-NPs on glycolipid metabolism remain understudied, and effective methods for removing plastic pollutants deposited in the body are yet to be established. These findings provide valuable insights for future research in this field.