Critical review on microplastics in fecal matter: Research progress, analytical methods and future outlook

Do microplastics accumulate in penguin internal organs? Evidence from Svenner island, Antarctica

The prevalence of microplastics (MPs, <5 mm) in natural environments presents a formidable global environmental threat MPs can be found from the Arctic to Antarctica, including glaciers. Despite their widespread distribution, studies on MP accumulation in apex predators inhabiting Polar Regions remain limited. The objective of this study was to conduct a comprehensive examination, for the first time, of MP bioaccumulation in various organs and tissue of Adélie penguins. This investigation comprehends the gastrointestinal tract (GIT), scat, internal organ (lung, trachea, spleen, and liver) and tissue (muscle) samples collected from Svenner Island, Antarctica during the 39th Indian expedition to Antarctica in 2019-2020. Our analyses revealed the presence of 34 MPs across the GIT, scat, lung, and trachea samples, with no MPs detected in muscle, spleen, or liver tissues. Blue-colored microfibers (>50 %) and MPs smaller than 1 mm (38 %) in size were prominently observed. Polymer characterization utilizing μ-FTIR spectroscopy identified low-density polyethylene (LDPE) (~63 %) as the predominant polymer type. The accumulation of MP fibers in the gastrointestinal tract and scat of Adélie penguins may originate from marine ambient media and prey organisms. Furthermore, the presence of LDPE fibers in the trachea and lungs likely occurred through inhalation and subsequent deposition of MPs originating from both local and long-range airborne sources. The identification of fibers ranging between 20 and 100 μm within the trachea suggests a plausible chance of cellular deposition of MPs. Overall our findings provide valuable insights into the organ-specific accumulation of MPs in apex predators. Adélie penguins emerge as promising environmental bio-monitoring species, offering insights into the potential trophic transfer of MPs within frigid environments.

Microplastics in faeces of European shags Gulosus aristotelis in central Norway

Plastic pollution is an increasing problem in the marine environment, and microplastics are frequently ingested by wildlife, including seabirds. Faeces are an increasingly used matrix to quantify egested microplastics. We investigated microplastics in 36 faeces samples from chicks of European shags (Gulosus aristotelis) sampled at Sklinna, central Norway in 2021. Small particles <300 μm (62 %) dominated the material. Out of 465 particles measured with Raman spectroscopy, 32 were identified as microplastics (21 fragments, 4 fibres). 69.4 % of faecal samples contained microplastics, with on average 17 microplastic particles per g faeces dry weight. Sixteen of the 36 samples originated from siblings sampled within the same hour, and plastic loads of these samples were more similar to each other compared to those from other individuals. This suggests that a sample from one chick is representative for all siblings at a given moment in time and proofs parental transfer of MP.

Microplastics footprint in nature reserves-a case study on the microplastics in the guano from Yancheng Wetland Rare Birds National Nature Reserve, China

Bio-ingestion of microplastics poses a global threat to ecosystems, yet studies within nature reserves, crucial habitats for birds, remain scarce despite the well-documented ingestion of microplastics by avian species. Located in Jiangsu Province, China, the Yancheng Wetland Rare Birds Nature Reserve is home to diverse bird species, including many rare ones. This study aimed to assess the abundance and characteristics of microplastics in common bird species within the reserve, investigate microplastic enrichment across different species, and establish links between birds' habitat types and microplastic ingestion. Microplastics were extracted from the feces of 110 birds, with 84 particles identified from 37.27% of samples. Among 8 species studied, the average microplastic abundance ranged from 0.97 ± 0.47 to 43.43 ± 61.98 items per gram of feces, or 1.5 ± 0.87 to 3.4 ± 1.50 items per individual. The Swan goose (Anser cygnoides) exhibited the highest microplastic abundance per gram of feces, while the black-billed gull (Larus saundersi) had the highest abundance per individual. The predominant form of ingested microplastics among birds in the reserve was fibers, with polyethylene being the most common polymer type. Significant variations in plastic exposure were observed among species and between aquatic and terrestrial birds. This study represents the first quantitative assessment of microplastic concentrations in birds within the reserve, filling a crucial gap in research and providing insights for assessing microplastic pollution and guiding bird conservation efforts in aquatic and terrestrial environments.

Take-out food enhances the risk of MPs ingestion and obesity, altering the gut microbiome in young adults

Young people are consuming large amounts of microplastics (MPs) due to the booming development of the take-out industry. To investigate the association between MPs exposure and obesity, 121 volunteers were divided into high MPs exposure (HME) and low MPs exposure (LME) according to the frequency of take-out food consumption. Fecal samples were collected for MPs detection using Raman spectra analysis, and identification of the gut microbiota was based on 16 S rDNA/ITS, while metabolite analysis was performed by LC-MS/MS. High levels of MPs and body mass index (BMI) were observed in the HME group (P < 0.05). Both the multiple linear regression (MLR) model and the binary logistic regression (BLR) (OR: 1.264, 95 % CI: 1.108-1.441, P < 0.001) analysis showed a positive correlation between MPs content and BMI. Microbial community analysis revealed that Veillonella, Alistipes and Dothideomycotes (pathogenic fungi) increased in HME participants, whereas Faecalibacterium and Coprococcus decreased. Meanwhile, analysis of stool metabolites showed that vancomycin resistance, selenocompound metabolism and drug metabolism pathways were enhanced in HME participants. These findings indicate that frequent consumption of take-out food may elevate the intake of microplastics, consequently modifying the gut microbiota and metabolites of young adults, and could represent a potential risk factor for obesity.

Using feces to indicate plastic pollution in terrestrial vertebrate species in western Thailand

Plastic pollution is a widespread and growing concern due to its transformation into microplastics (MPs), which can harm organisms and ecosystems. This study, aimed to identify plastic pollution in the feces of terrestrial vertebrates using convenience sampling both inside and outside protected areas in Western Thailand. We hypothesized that MPs are likely to be detectable in the feces of all vertebrate species, primarily in the form of small black fragments. We predicted varying quantities of MPs in the feces of the same species across different protected areas. Furthermore, we expected that factors indicating human presence, landscape characteristics, scat weight, and the MP abundance in water, soils, and sediments would influence the presence of plastics in feces. Among 12 terrestrial species studied, potential MPs were found in 41.11% of 90 samples, totaling 83 pieces across eight species including the Asian elephant (Elephas maximus), Eld's deer (Rucervus eldii), Dhole (Cuon alpinus), Gaur (Bos gaurus), Sambar deer (Rusa unicolor), Wild boar (Sus scrofa), Northern red muntjac (Muntiacus vaginalis), and Butterfly lizard (Leiolepis belliana). Specifically, 3.61% of all potential MPs (three pieces) were macroplastics, and the remaining 96.39% were considered potential MPs with the abundance of 0.92 ± 1.89 items.scat-1 or 8.69 ± 32.56 items.100 g-1 dw. There was an association between the numbers of feces with and without potential plastics and species (χ2 = 20.88, p = 0.012). Most potential plastics were fibers (95.18%), predominantly black (56.63%) or blue (26.51%), with 74.70% smaller than two millimeters. Although there were no significant associations between species and plastic morphologies, colors, and sizes, the abundance classified by these characteristics varied significantly. FTIR identified 52.38% as natural fibers, 38.10% as synthetic fibers (rayon, polyurethane (PUR), polyethylene terephthalate (PET), polypropylene (PP), and PUR blended with cotton), and 9.52% as fragments of PET and Polyvinyl Chloride (PVC). Human-related factors were linked to the occurrence of potential plastics found in the feces of land-dwelling wildlife. This study enhances the understanding of plastic pollution in tropical protected areas, revealing the widespread of MPs even in small numbers from the areas distant from human settlements. Monitoring plastics in feces offers a non-invasive method for assessing plastic pollution in threatened species, as it allows for easy collection and taxonomic identification without harming live animals. However, stringent measures to assure the quality are necessitated to prevent exogenous MP contamination. These findings underscore the importance of raising awareness about plastic pollution in terrestrial ecosystems, especially regarding plastic products from clothing and plastic materials used in agriculture and irrigation systems.

Set up and validation of a method to analyse microplastics in stool and small intestine samples

The contamination of microplastics in humans is of increasing concern. Therefore, the aim of this study was to develop effective methods to determine the concentration and types of microplastics entering human digestive system. To study levels of MPs contamination in humans, an excellent indicator are stools. Indeed, stools, and thus the digestive system, can be an excellent indicator of the level of MPs contamination in humans. Hence, objective was to find effective methods to extract, quantify and characterize microplastics in stool and small intestine samples. The samples studied were human stools and pig jejunum (which has human-like characteristics). The methods were optimized by observing extraction efficiency, compatibility by Fourier-transform infrared spectroscopy (FTIR) characterization and non-deformation of the microplastics. The steps of the procedure were: • Sampling to avoid plastic contamination • Non-aggressive chemical and enzymatic digestion • Counting and characterization The methods were optimized and validated, observing recovery and repeatability. Therefore, two simple, effective methods with high analytical performance have been developed. The MPs present in the stool and intestine samples were counted by stereoscopic microscope and characterized by FTIR, finding several types of MPs such as synthetic cellulose, polyethylene, polypropylene, polystyrene, and polyethylene terephthalate, among others.

Identification and Visualization of Polystyrene Microplastics/Nanoplastics in Flavored Yogurt by Raman Imaging

The contamination of food by microplastics has garnered widespread attention, particularly concerning the health risks associated with small-sized microplastics. However, detecting these smaller microplastics in food poses challenges attributed to the complexity of food matrices and instrumental and method limitations. Here, we employed Raman imaging for visualization and identification of polystyrene particles synthesized in polymerization reactions, ranging from 400 to 2600 nm. We successfully developed a quantitative model of particle size and concentration for polystyrene, exhibiting excellent fit (R2 of 0.9946). We established procedures for spiked flavored yogurt using synthesized polystyrene, providing fresh insights into microplastic extraction efficiency. Recovery rates calculated from models validated the method's feasibility. In practical applications, the assessment of the size, type, shape, and quantity of microplastics in unspiked flavored yogurt was conducted. The most common polymers found were polystyrene, polypropylene, and polyethylene, with the smallest polystyrene sizes ranging from 1 to 10 μm. Additionally, we conducted exposure assessments of microplastics in branded flavored yogurt. This study established a foundation for developing a universal method to quantify microplastics in food, covering synthesis of standards, method development, validation, and application.

From organic fertilizer to the soils: What happens to the microplastics? A critical review

In recent, soil microplastic pollution arising from organic fertilizers has been of a great increasing concern. In response to this concern, this review presents a comprehensive analysis of the occurrence and evolution of microplastics in organic fertilizers, their ingress into the soil, and the subsequent impacts. Organic fertilizers are primarily derived from solid organic waste generated by anthropocentric activities including urban (daily-life, municipal wastes and sludge), agricultural (manure, straw), and industrial (like food industrial waste etc.) processes. In order to produce organic fertilizer, the organic solid wastes are generally treated by aerobic composting or anaerobic digestion. Currently, microplastics have been widely detected in the raw materials and products of organic fertilizer. During the process of converting organic solid waste materials into fertilizer, intense oxidation, hydrolysis, and microbial actions significantly alter the physical, chemical, and surface biofilm properties of the plastics. After the organic fertilizer application, the abundances of microplastics significantly increased in the soil. Additionally, the degradation of these microplastics often promotes the adsorption of organic pollutants and affects their retention time in the soil. These microplastics, covered by biofilms, also significantly alter soil ecology due to the unique properties of the biofilm. Furthermore, the biofilms also play a role in the degradation of microplastics in the soil environment. This review offers a new perspective on the soil environmental processes involving microplastics from organic fertilizer sources and highlights the challenges associated with further research on organic fertilizers and microplastics.

Tracking anthropogenic microparticles in wildlife of an alpine insular environment

Despite the isolation of remote natural regions, it has been discovered that they are experiencing the accumulation of anthropogenic microparticles (i.e., microplastics or natural or semisynthetic cellulosic particles). Teide National Park (Canary Islands, Spain) is a high-mountain protected area known for its rich biodiversity. This study aims to assess the occurrence of coloured anthropogenic particles in the faecal matter of wild mammals, specifically rabbits and mouflons, residing in the park. With this purpose, faeces were collected from 68 systematically distributed sampling points. A stereomicroscopy-guided grinding process allowed a chemical-free and quick visual inspection of 616 individual excreta, revealing that 96% were particle-free. However, 37 anthropogenic particles were found, which correspond to 0.79 ± 0.20 items per gram of dry faecal matter. The archetypical particle was a cellulosic blue microfibre of 2721 ± 407 µm, though poly(ethylene-vinyl acetate) and polypropylene were also identified via micro Fourier-transform infrared spectroscopic analysis. Atmospheric deposition and touristic pressure may be the sources of the anthropogenic particles, as they were randomly found in 36% of the sampling points. These findings represent the first evidence of anthropogenic particle ingestion by wild rabbits and mouflons, signifying the introduction of microplastics into terrestrial food chains in a remote high-mountain environment.

Antibiotics and microplastics in manure and surrounding soil of farms in the Loess Plateau: Occurrence and correlation

The wide use of animal manure in farmland operations is a source of soil nutrients. However, the return of manure affected antibiotics and microplastics in the soil, thus the potential ecological risks cannot be overlooked. This study investigated the distribution of different antibiotics and microplastics and their correlation. It was found that multiple classes of veterinary antibiotics and microplastics could be detected simultaneously in most manure and soil. In manure, the average concentration of tetracycline antibiotics was higher than fluoroquinolones and sulfonamides. A much lower concentration of antibiotics was found in the soil samples relative to manure. The abundance of microplastics ranged from 21,333 to 88,333 n/kg in manure, and the average abundance was 50,583 ± 24,318 n/kg. The average abundance was 3056 ± 1746 n/kg in the soil. It confirmed that applying organic fertilizer to agricultural soil and the application of plastic mulch in farmlands introduced microplastics. Moreover, microplastics were found to be significantly correlated with antibiotics (r = 0.698, p < 0.001). The correlation between microplastics and antibiotics in soil was significantly weaker than that in manure. Farms could be the hotspot for the co-spread of microplastics and antibiotics. These findings highlighted the co-occurrence of antibiotics and microplastics in agricultural environments.

A non-invasive method of microplastics pollution quantification in green sea turtle Chelonia mydas of the Mexican Caribbean

Due to the amply exposure of marine turtles to marine plastic pollution, this is a reason that the green sea turtle Chelonia mydas makes a good candidate species as a bioindicator for plastic pollution. Turtle feces were collected at Isla Blanca on the northeast Caribbean coast of the Yucatan Peninsula, Mexico. Microplastic extraction was done following Hidalgo-Ruz et al. (2012) and Masura et al. (2015) methods. After organic matter degradation of the feces samples, microplastics were identified and quantified by stereomicroscope. Their morphostructure was analyzed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, while their composition was determined by Fourier transform infrared spectroscopy and Raman spectroscopy. Microplastics (MP) abundance ranged from 10 ± 2 MP·g-1 to 89 ± 3 MP·g-1. Kruskal Wallis test (KW = 70.31, p < 0.001) showed a significant difference between 22 green turtles analyzed. Most of the microplastics were fiber type. Blue, purple, and transparent fibers were the most abundant. The identified microplastics were nylon (polyamide), PVC, polypropylene, polyester, and viscose (cellulose). The non-invasive method used here allowed the detection of microplastic pollution and is promising for long-term microplastic pollution monitoring.

Synergistic effects of microplastic and lead trigger physiological and biochemical impairment in a mangrove crab

Microplastics (MP) are vectors for other environmental contaminants, such as metals, being a considerable problem, especially in the aquatic ecosystem. To investigate the combined effects of MP (high density polyethylene) with lead (Pb), we exposed the mangrove fiddler crab Minuca vocator to Pb (50 mg L-1), and MP (25 mg L-1) alone and in mixture, for 5 days. We aimed to determine Pb and MP bioaccumulation, as well as physiological (oxygen consumption and hemolymph osmolality) and biochemical (superoxide dismutase, catalase, glutathione peroxidase, and lipid peroxidation) traits effects. Co-exposure of MP and Pb significantly increased the bioaccumulation of Pb, but reduced MP tissue accumulation. Regarding the physiological traits, increasing osmolality and oxygen consumption rates compared to the control were observed, particularly in the combined Pb and MP exposure. As to biochemical traits, the combination of Pb and MP induced the most significant responses in the enzymatic profile antioxidant enzyme activity. The catalase (CAT), glutathione peroxidase (GPx), and dismutase superoxide (SOD) decreased compared to individual exposure effects; the combination of MP and Pb had a synergistic effect on promoting lipid peroxidation (LPO). The co-exposure of MP and Pb acted synergistically when compared to the effects of the isolated compounds. Due to the increasing MP contamination in mangroves, more severe physiological and biochemical effects can be expected on mangrove crabs exposed to metal contamination.

Are microplastics in livestock and poultry manure an emerging threat to agricultural soil safety?

Microplastics (MPs) have attracted much attention in recent years, due to the difficulty of degradation and threats to ecological systems and humans. Based on the analysis of 1429 articles on MPs in soil, we found that we know little about the behavior and fate of manure-born MPs from the livestock and poultry production systems to agriculture soils. This review summarizes the analytical methods for sampling, separation, and identification and the occurrence of MPs in livestock and poultry manure, mainly based on 7 surveys related to manure-born MPs. Then, the sources, fate, and environmental risks of MPs in livestock and poultry manure are discussed. MPs, heavy metals, pathogens, antibiotic resistance genes, and persistent organic pollutants are common pollutants in livestock and poultry manure. Worse, manure-born MPs will become smaller, rougher, and more numerous and could easily form more toxic compound pollution after complicated processes of manure treatment, which seriously threatens agricultural soil safety. Finally, an outlook is offered for future research. We hope this article to attract attention to the risks of MPs in livestock and poultry manure and provide a reference for future research.

Fate and disposition of [14C]-polystyrene microplastic after oral administration to laying hens

Micro/nanoplastics (MP) are emerging environmental contaminants of great concern because of their ubiquitous distribution in air, soil, water, and food. Reports have described MP in the excreta of food animals, but their absorption, distribution, and elimination in terrestrial animals used for human consumption is essentially unexplored. To determine the absorption and distribution of [14C]-polystyrene (PS) MP, laying hens (n = 15) were bolus dosed with 10 μCi/hen (11.1 ± 0.8 mg/kg) and the extent of radioactivity in blood and tissues was determined in birds harvested on withdrawal days (WD) 1, 2, 3, 4, and 7 (3 hens per WD). Radiocarbon was also determined in egg fractions and excreta collected throughout the study. Blood, eggs, and tissues contained a total of <1 % of the administered dose, demonstrating that polystyrene microparticles were poorly absorbed. Recovery of radioactivity in excreta within the first withdrawal day was nearly quantitative (96.8 ± 14.5 %, n = 15), suggesting exposure of poultry to dietary PS-MP would not likely represent subsequent food safety risks and that most PS-MP present in poultry diets would return to the environment.

Micro and nano plastics in food: A review on the strategies for identification, isolation, and mitigation through photocatalysis, and health risk assessment

Over the past few years, it has become increasingly evident that microplastic pollutant heavily contaminates water sources, posing a potential threat to both human and wildlife. These plastic pollutants do not get degraded efficiently by natural processes and the existing traditional treatment methods are incapable of fully eradicating them. In this regard, degradation of microplastic contaminants through photocatalytic methods has emerged as a powerful technique. Unfortunately, only a limited number of investigations have been reported in the field of photocatalytic degradation of microplastics. This comprehensive assessment focuses on the detailed analysis of the latest cutting edge engineered technologies aimed at efficiently separating, identifying microplastic contaminants present in food samples and degrading them through photocatalysis. Moreover, detailed information on various instrumental techniques that can be adopted to analyze the isolated micro sized plastic particles has been discussed. The assessment and degradation of these micro contaminants through photocatalytic methods is still in juvenile stage and there are lot of rooms to be explored. The need for profound contemplation on methods to degrade them through photocatalytic approaches as well as their possible health risks to humans motivated us to bring out this review.

Anthropogenic debris ingestion in a tropical seabird community: Insights from taxonomy and foraging distribution

Oceans have been considered as an unlimited supply of goods and services, but resource extraction and waste disposal became ubiquitous and have been damaging the health of marine ecosystems. Finding suitable sentinel species of the human impacts on the oceans is thus imperative, since they may work as early warnings of disruptive situations. In this study, we investigated how taxonomy and foraging distribution influenced the occurrence of anthropogenic debris among five seabird species inhabiting the tropical Atlantic region. Occurrence of anthropogenic debris was assessed using faeces of breeding individuals as a proxy of ingestion. A total of 268 particles were extracted from all samples. The categories "fragments" and "fibres", as well as the colour "blue", were the most prevalent characteristics across species. There was a high diversity of polymers from cellulosic particles to synthetic plastics (Anthropogenic Cellulosic 26.9 %; Polyester 7.7 %; Varnish 5.8 %; Polypropylene 1.9 %). Species with a more coastal foraging strategy exhibited higher occurrence and number of anthropogenic debris when compared to species foraging comparably more in pelagic areas. This suggests that anthropogenic debris are more prevalent in coastal foraging areas, where human activities occur in higher number and frequency (e.g., fisheries) and sources of freshwater input from inland are at close distance. These results provide more evidence to the growing perception on the ubiquity and diversity of anthropogenic debris in the marine environment, and further support the usefulness of using seabirds as bio-indicators of anthropogenic pollution in both neritic and oceanic regions.

Exposure to irregular microplastic shed from baby bottles activates the ROS/NLRP3/Caspase-1 signaling pathway, causing intestinal inflammation

Irregularly shaped microplastics (MPs) released from infant feeding bottles (PP-IFBs) may exhibit increased cytotoxicity, in contrast to the commonly studied spherical MPs. This study presents an initial analysis of the thermal-oxidative aging process of plastic shedding from feeding bottles, and investigates the inflammatory response induced by these atypical MPs in human intestinal cells (Caco-2). The PP-IFBs' surface displayed non-uniform white patches and increased roughness, revealing substantial structural alteration and shedding, especially during actions such as shaking, boiling water disinfection, and microwave heating. FT-IR and 2D-COS analyses revealed that oxygen targeted the C-H and C-C bonds of polypropylene molecular chain, producing RO· and ·OH, thereby hastening polypropylene degradation. When human intestinal cells were exposed to MPs from PP-IFBs, oxidative stress was triggered, resulting in lowered glutathione levels, augmented reactive oxygen species (ROS), and heightened lipid peroxidation. Elevated levels of pro-inflammatory cytokines (IL-6 and TNFα) signified an active inflammatory process. The inflammatory response was notably more intense when exposed to MPs released through boiling water disinfection and microwave heating treatments, primarily due to the larger quantity of MPs released and their higher proportion of smaller particles. Furthermore, the NLRP3 inflammasome was identified as critical in initiating this inflammatory chain reaction due to the mitochondrial ROS surge caused by MPs exposure. This was further validated by inhibitor studies, emphasizing the role of the ROS/NLRP3/Caspase-1/IL-1β signaling pathway in in promoting intestinal inflammation. Therefore, swift actions are recommended to protect infants against the potential health effects of MPs exposure.

Detection and quantification of microplastic pollution in the endangered Galapagos sea lion

Marine debris pollution poses a significant global threat to biodiversity, with plastics being the primary debris type found in oceans due to their low-cost production and high demand worldwide. Microplastics (MPs, <5 mm in size) are highly bioavailable to a wide range of marine taxa, including marine mammals, through direct and indirect ingestion routes (i.e., trophic transfer). Recently, MP pollution has been detected on the Galapagos Marine Reserve, so in this study we developed a baseline framework for MP pollution in the Galapagos sea lion (GSL, Zalophus wollebaeki) through scat-based analysis. We collected 180 GSL scat samples from the southeast region following strict quality assurance/quality control protocols to detect, quantify and characterize physical-chemical properties of MPs through visual observations and μFT-IR spectroscopy. We recovered 81 MPs of varying sizes and colors in 37 % of samples (n = 66/180), consisting mostly of fibers (69 %, x¯ = 0.31 ± 0.57 particles scat-1). The number of particles per gram of sample wet weight ranged from 0.02 to 0.22 (x¯ = 0.04 ± 0.05 particles scat wet g-1). El Malecón and Punta Pitt rookeries at San Cristobal Island had the highest number of MPs (x¯ = 0.67 ± 0.51 and 0.43 ± 0.41 particles scat-1, respectively), and blue-colored particles were the most common in all samples. We identified eleven polymers in 46 particles, consisting mostly of polypropylene-polyethylene copolymer, polypropylene, cellulose, polyethylene, and polyvinyl chloride. The textile, fishing, and packaging industries are likely significant sources of microfibers into this insular ecosystem. Our results suggest that the GSL is exposed to MPs due to anthropogenic contamination that is subsequently transferred through trophic processes. These findings provide an important baseline framework and insights for future research on MP pollution in the region, as well as for management actions that will contribute to the long-term conservation of the GSL.

Microplastics are overestimated due to poor quality control of reagents

Microplastics are widely distributed in the environment and pose potential ecological risks, increasing to be one of the most important environmental pollutants. However, when assessing the characteristics of microplastic contamination in environmental samples, inadequate quality control measures for the working solutions may introduce additional microplastic contamination and lead to an overestimation of microplastic abundance in the samples. In this study, we evaluated the microplastic contamination characteristics in commonly used flotation and digestion reagents to assess errors caused by microplastics in the reagents. The results showed that the abundance of microplastics in the reagents ranged from 0.8 to 43.4 items/g, with the abundance of microplastics in flotation reagents being lower than that in digestion reagents. The shapes of the detected microplastics included particles, fibers, and fragments, and their size and outline were generally small, with most being below 100 µm. The most common types of polymers detected were polyethylene and polypropylene. In order to improve the universality and readability of the results, the detected microplastic abundances were converted into the actual application concentration of the working fluid. It was found that the potential contamination of microplastics in untreated flotation solutions ranged from 1.5 to 30.8 items/mL, while in digestion solutions ranged from 0.1 to 2.3 items/mL. Our study emphasizes the need for quality control measures, such as suction filtration, when evaluating microplastics in environmental samples or conducting chemical and biological tests related to microplastics.

Development of a Resilience Parameter for 3D-Printable Shape Memory Polymer Blends

The goal of this paper was to establish a metric, which we refer to as the resilience parameter, to evaluate the ability of a material to retain tensile strength after damage recovery for shape memory polymer (SMP) systems. In this work, three SMP blends created for the additive manufacturing process of fused filament fabrication (FFF) were characterized. The three polymer systems examined in this study were 50/50 by weight binary blends of the following constituents: (1) polylactic acid (PLA) and maleated styrene-ethylene-butylene-styrene (SEBS-g-MA); (2) acrylonitrile butadiene styrene (ABS) and SEBS-g-MA); and (3) PLA and thermoplastic polyurethane (TPU). The blends were melt compounded and specimens were fabricated by way of FFF and injection molding (IM). The effect of shape memory recovery from varying amounts of initial tensile deformation on the mechanical properties of each blend, in both additively manufactured and injection molded forms, was characterized in terms of the change in tensile strength vs. the amount of deformation the specimens recovered from. The findings of this research indicated a sensitivity to manufacturing method for the PLA/TPU blend, which showed an increase in strength with increasing deformation recovery for the injection molded samples, which indicates this blend had excellent resilience. The ABS/SEBS blend showed no change in strength with the amount of deformation recovery, indicating that this blend had good resilience. The PLA/SEBS showed a decrease in strength with an increasing amount of initial deformation, indicating that this blend had poor resilience. The premise behind the development of this parameter is to promote and aid the notion that increased use of shape memory and self-healing polymers could be a strategy for mitigating plastic waste in the environment.

Effect of salinity on microplastic accumulation and osmoregulatory toxicity in the fiddler crab Minuca rapax

The effects of salinity on the accumulation and toxicity of microplastics (MPs) in mangrove invertebrates are still scarcely described. We assessed the accumulation and osmoregulatory toxicity of the estuarine fiddler crab Minuca rapax, exposed to 25 mg L^-1 of high-density polyethylene MPs at three combinations of osmotic media (hypo- 6, iso- 25, or hyper-35 psu), in 1, 3 and 5 days of exposure. Gills accumulated more MPs than the digestive tract (DT) and muscle. MP accumulation in the gills and DT was enhanced at 6 psu and reduced at 21 and 35 psu after 1 day of exposure. Muscle MP accumulation was not affected by salinity or exposure time. Osmotic regulation was unaffected by MP exposure in any exposure time. Our findings demonstrate that M. rapax accumulates MPs in gills and DT depending on the salinity and that MPs are not osmoregulatory toxicant for this species.

Presence, variation, and potential ecological impact of microplastics in the largest shallow lake of Central Europe

The presence of microplastics (MPs) in the global ecosystem has generated a rapidly growing concern worldwide. Although their presence in the marine environment has been well-studied, much less data are available on their abundance in freshwaters. MPs alone and in combination with different chemicals has been shown to cause acute and chronic effects on algae and aquatic invertebrate and vertebrate species at different biological levels. However, the combined ecotoxicological effects of MPs with different chemicals on aquatic organisms are still understudied in many species and the reported data are often controversial. In the present study, we investigated, for the first time, the presence of MPs in Lake Balaton, which is the largest shallow lake of Central Europe and an important summer holiday destination. Moreover, we exposed neonates of the well-established ecotoxicological model organism Daphnia magna to different MPs (polystyrene [3 μm] or polyethylene [≤ 100 μm]) alone and in combination with three progestogen compounds (progesterone, drospirenone, levonorgestrel) at an environmentally relevant concentration (10 ng L^-1) for 21 days. The presence of 7 polymer types of MPs in the size range of 50-100 μm was detected in Lake Balaton. Similarly to the global trends, polypropylene and polyethylene MPs were the most common types of polymer. The calculated polymer-independent average particle number was 5.5 particles m^-3 (size range: 50 μm - 100 μm) which represents the values detected in other European lakes. Our ecotoxicological experiments confirmed that MPs and progestogens can affect D. magna at the behavioral (body size and reproduction) and biochemical (detoxification-related enzyme activity) levels. The joint effects were negligible. The presence of MPs may lead to reduced fitness in the aquatic biota in freshwaters such as Lake Balaton, however, the potential threat of MPs as vectors for progestogens may be limited.

From the environment into the biomass: microplastic uptake in a protected lamprey species

The relationship between the ubiquitous presence of microplastics in the environment and exposure of biota needs to be better understood, particularly for vulnerable species and their habitats. In this study, we address the presence of microplastics in the riverine habitat of a threatened lamprey species (Lampetra sp.), both in habitats with protective interventions in place (designated as Special Areas of Conservation), and those without these protective interventions. By sampling both riverbed sediments and larval lamprey, we provide a direct comparison of the microplastic loadings in both, and insights into how knowledge of sediment loadings might predict biological uptake. Microplastic particles, analysed using micro-Fourier transform infrared (μFTIR) spectroscopy, were detected in all samples of lamprey larvae and paired sediment, ranging in abundance from 1.00 to 27.47 particles g^-1 in dry lamprey gastrointestinal tract (GIT) tissue, and 0.40 to 105.41 particles g^-1 in dry sediment. The most urbanised catchment exhibited the highest average microplastic particle count in both lamprey and sediment. Across sites, the microplastic abundance in lamprey GIT tissue was not correlated with that of the surrounding sediment, suggesting that either specific polymer types are retained or other factors such as larvae residence time within sediment patches may influence biological uptake. The most encountered polymer types in lamprey from their immediate habitat were polyurethane, polyamide, and cellulose acetate. To the best of our knowledge, this is the first study to document microplastic contamination of larval lamprey in-situ, contributing another potential stressor to the population status of a vulnerable species. This highlights where further research on the impacts of plastic contamination of freshwater environments is needed to aid conservation management of this ecologically important species.

Investigation of Microplastics (≥10 μm) in Meconium by Fourier Transform Infrared Microspectroscopy

Microplastics are prevalent emerging pollutants with widespread distribution in air, land and water. They have been detected in human stool, blood, lungs, and placentas. However, human fetal microplastic exposure remains largely under-studied. To assess fetal microplastic exposure, we investigated microplastics using 16 meconium samples. We used hydrogen peroxide (H₂O₂), nitric acid (HNO₃) and a combination of Fenton's reagent and HNO₃ pretreatment methods respectively to digest the meconium sample. We analyzed 16 pretreated meconium samples with an ultra-depth three-dimensional microscope and Fourier transform infrared microspectroscopy. The result showed that H₂O₂, HNO₃ and Fenton's reagent combined with HNO₃ pretreatment methods could not digest our meconium samples completely. Alternatively, we developed a novel approach with high digestion efficiency using petroleum ether and alcohol (4:1, v/v), HNO₃ and H₂O₂. This pretreatment method had good recovery and non-destructive advantages. We found no microplastics (≥10 μm) in our meconium samples, indicating that microplastic pollution levels in the fetal living environment are miniscule. Different results between previous studies' and ours underscore that comprehensive and strict quality control are necessary for further studies on microplastic exposure using human bio-samples.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

Assessing microplastic exposure of the Critically Endangered Mediterranean monk seal (Monachus monachus) on a remote oceanic island

Microplastics (<5 mm) are a ubiquitous marine pollutant which are highly bioavailable to marine organisms across all trophic levels. Marine predators are especially vulnerable to microplastic pollution through direct and indirect ingestion (e.g., trophic transfer) due to their high trophic position. In particular, oceanic islands are more susceptible to plastic accumulation, increasing the relative number of microplastics in the environment that are available for consumption. The dynamics of microplastic accumulation in marine predators inhabiting remote islands, however, is sparsely documented. Here we describe microplastic exposure in the Critically Endangered Mediterranean monk seal (Monachus monachus) from the Madeira archipelago (Northeast Atlantic) using scat-based analysis. Microplastics were recovered from 18 scat samples collected between 2014-2021 and were characterized to the polymer level using Fourier-Transform Infrared (u-FTIR) spectroscopy. A total of 390 microplastic particles were recovered, ranging between 0.2-8.6 particles g^-1 dry weight (mean 1.84 ± 2.14 particles g^-1) consisting mainly of fragments (69 %) of various sizes and polymer composition (e.g., PE, PET, PS). Microplastic prevalence (100 % of samples analysed) was higher than what has been previously recorded using scat-based analysis in other pinniped species. Our results suggest that the levels of microplastic pollution in the coastal food-web in the Madeira archipelago are relatively high, placing higher-trophic level organisms at increased risk of microplastic consumption, including humans. This study provides the first insights into microplastic exposure to Madeira's monk seals that may contribute to future management decisions for the species and their long-term survival.

Efficient extraction of small microplastic particles from rat feed and feces for quantification

To date, microplastic is ubiquitously encountered in the environment. Studies analyzing microplastic in terrestrial ecosystems, including animal feces and feed, are few. Microplastic quantification method validation and harmonization are not yet far developed. For the analysis of small microplastic, approximately <0.5 mm, extraction from organic and inorganic materials is fundamental prior to quantitative and qualitative analysis. Method validation, including recovery studies, are necessary throughout the analytical chain. In this study, we developed an optimized, efficient protocol with a duration of 72 h for the digestion of laboratory rat feed and feces. A combination of a mild acidic (H₂O₂ 15%; HNO₃ 5%) and an alkaline treatment (10% KOH) dissolving the previous filter, followed by enzymatic digestion (Viscozyme®L) proved to be efficient for the extraction and identification of spiked polyamide (15-20 μm) and polyethylene (40-48 μm) from feed and feces samples from rats, showing high recovery rates. Extracted rat feces samples from an in vivo study in which Wistar rats were fed with feed containing microplastic were analyzed with pyrolysis-gas chromatography-Orbitrap™ mass spectrometry, quantifying recovered microplastic in rat feces in environmentally relevant concentrations. The presented three-step protocol provides a suitable, time and cost-effective method to extract microplastic from rat feed and feces.

A new approach to extracting biofilm from environmental plastics using ultrasound-assisted syringe treatment for isotopic analyses

Plastics are one of the ubiquitous and artificial types of substrates for microbial colonization and biofilm development in the aquatic environment. Characterizing plastic-associated biofilms is key to the better understanding of organic material and mineral cycling in the "Plastisphere"-the thin layer of microbial life on plastics. In this study, we propose a new method to extract biofilms from environmental plastics, in order to evaluate the properties of biofilm-derived organic matter through stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope signatures and their interactions with radionuclides especially radiocesium (¹³⁷Cs). The extraction method is simple and cost-effective, requiring only an ultrasonic bath, disposable plastic syringes, and a freeze drier. After ultrasound-assisted separation from the plastics, biofilm samples were successfully collected via a sequence of syringe treatments, with less contamination from plastics and other mineral particles. Effective removal of small microplastics from the experimental suspension was satisfactorily achieved using the method with syringe treatments. Biofilm-derived organic matter samples (14.5-65.4 mg) from four river mouths in Japan showed ¹³⁷Cs activity concentrations of <75 to 820 Bq·kg^-1 biofilm (dw), providing evidence that environmental plastics, mediated by developed biofilms, serve as a carrier for ¹³⁷Cs in the coastal riverine environment. Significant differences in the δ¹³C and δ¹⁵N signatures were also obtained for the biofilms, indicating the different sources, pathways, and development processes of biofilms on plastics. We demonstrate here a straightforward method for extracting biofilms from environmental plastics; the results obtained with this method could provide useful insights into the plastic-associated nutrient cycling in the environment.

Polystyrene nanoparticles enhance the adverse effects of di-(2-ethylhexyl) phthalate on male reproductive system in mice

Coexposure of nanoplastics (NPs) with other pollutants adsorbed from the surroundings has received extensive attention. Currently, the combined effects of NPs and plasticizers remain unclear. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer that has raised much concern owing to its ubiquitous pollution and endocrine-disrupting potential. This study aimed to investigate the toxic effects on the male reproductive system upon coexposure to NPs and DEHP. The C57BL/6J mice were orally administrated with polystyrene nanoparticles (PSNPs), DEHP or both for 35 days to evaluate their effects on sperm quality, histology of testes and epididymides, testicular transcriptomic characteristics as well as expression of some important genes in the epididymides. The low-dose PSNPs used here did not induce significant changes in sperm quality, while DEHP alone or cotreatment with DEHP and PSNPs caused notable impairment, mainly manifesting as decreased sperm quality and aberrant structure of the testis and epididymis. Moreover, enhanced toxic effects were found in the cotreatment group when compared with the individual DEHP treatment group, as manifested by more obvious alterations in the sperm parameters as well as histological changes in the testis and epididymis. Testicular transcriptomic analysis revealed differential regulation of genes involved in immune response, cytoplasmic pattern recognition receptor signaling pathways, protein ubiquitination, oxidative stress, necrotic cell death, ATP synthesis and the cellular respiratory chain. RT-qPCR verified that the expression patterns of Cenpb, Crisp1 and Mars were changed in testes, and genes relevant to epididymal function including Aqp9 and Octn2 were downregulated in epididymides, particularly in the cotreatment group. Collectively, our results emphasize that DEHP at an environmentally relevant dose can induce male reproductive toxicity, and PSNPs may aggravate the toxic effects.

Effects of polyamide microplastic on the transport of graphene oxide in porous media

With the rapid development of the nano-material and chemical industry, more and more microplastic (MP) and nano-material were discharged into the environment. In this study, a two-dimensional (2D) surface of Extended Darjaguin-Landau-Verwe-Overbeek (XDLVO) is proposed to quantitatively investigate the effect of polyamide (PA) on the transport of graphene oxide (GO) in porous media. The influences of mass fraction of PA, flow rate, GO concentration, ionic type and strength on the migration of GO in saturated porous media are investigated by column experiments and numerical models. The two-dimensional (2D) surfaces of XDLVO interaction energy between GO and GO, GO and QS, GO and PA, are firstly calculated to analyze the transport of GO in saturated porous media. Experimental results suggest the mobility of GO is enhanced when flow velocity and initial concentration of GO are increased. However, the mobility of GO is inhibited when the mass fraction of PA and ionic strength are increased. More important, the inhibitory effect of divalent cations on GO migration is stronger than that of monovalent cations. Simultaneously, XDLVO results suggest that ionic types and strengths are important factors affecting the mobility of GO in porous media, and the critical ionic strength is observed from the continuous variation of the secondary minimum trap of XDLVO interaction energy. Model results show that there is a linear relationship between the logarithm of the secondary minimum trap of XDLVO interaction energy and the parameters related to GO mobility, which suggests XDLVO energy surface has an important application significance in the accurate quantification of GO mobility in porous media. These findings contribute to GO transport affected by microplastic in porous media, thus laying a significant foundation for the environmental risk and contamination remediation.

First evidence of microplastics isolated in European citizens' lower airway

Microplastics (MPs) have been detected in all environmental locations, including the atmosphere. However, few studies have investigated the presence of airborne MPs in the human respiratory system. Our research purpose was to investigate these pollutants in the lower human airways of 44 adult European citizens, using bronchoalveolar lavage fluid (BALF) collection as a minimally invasive method, that enables the detection of these pollutants in living patients. We studied the relationship between the patients' life habits and physiological parameters, based on background information and medical and occupational history, and the concentration of MPs isolated from their respiratory systems. Our results indicate that most MPs were in the form of microfibers (MFs) (97.06%), with an average concentration of 9.18 ± 2.45 items/100 mL BALF, and only 5.88% (0.57 ± 0.27 items/100 mL BALF) were particulate MPs, without a significant relationship with environmental, physiological, or clinical factors. The average size was 1.73 ± 0.15 mm, with the longest dimension (9.96 mm) corresponding to a polyacrylic fiber. Taken together, the results demonstrated the occurrence of MPs in the lower human airway, although more studies are necessary to elucidate the negative effects these pollutants could induce in the human respiratory system and its associated diseases.

Exploring the adsorption behavior of benzotriazoles and benzothiazoles on polyvinyl chloride microplastics in the water environment

As a kind of emerging pollutant, microplastics (MPs) play an important role as a carrier for pollutant migration in the water environment. Carried by the MPs, benzotriazoles, and benzothiazoles (collectively referred to as BTs)¹ are ubiquitous water contaminants. In this paper, the adsorption behavior of BTs on polyvinyl chloride (PVC) MPs was first studied systematically to explain the adsorptive mechanisms and the consequential pollution caused by the absorption-desorption process. The studies on kinetics, isotherms, and thermodynamics revealed that the adsorption of BTs on PVC MPs was a multi-rate, heterogeneous multi-layer, and exothermic process, which was affected by external diffusion, intra-particle diffusion, and dynamic equilibrium. The factors including pH, salinity, and particle size also influenced the adsorption process. In the multi-solute system, competitive adsorption would occur between different BTs. The desorption of BTs from PVC MPs was positively associated with the increase of adsorption amount. Based on the results, the adsorption mechanisms of PVC MPs were clarified, involving hydrophobic interaction, electrostatic force, and non-covalent bonds. It was demonstrated that BTs in the water environment could most probably be accumulated and migrated through MPs, and eventually carried into organisms, posing an increased risk to the ecological environment.

The wedge clam Donax trunculus L., 1758 as a bioindicator of microplastic pollution

This study describes the use of D. trunculus as a bioindicator of microplastic (MPs) pollution due to beach urbanization related to the development of the Taghazout Bay tourist resort in Morocco. In six sites located on the coast, MPs densities ranged from 1.75 to 5.93 items per gram of D. trunculus wet weight. MPs contamination was significantly influenced spatiotemporally by the urbanization degree in the area. The shapes found were fibers (90.5%) and fragments (9.5%). The Fourier Transform Infrared Spectroscopy (FTIR) analysis reported two polymers: polyethylene (65%) and polypropylene (35%). MPs colors were dark and light, with a predominance of light blue (23.8%). The species ingested different sizes of MPs, mainly the 0.1 and 0.5 mm fractions. Scanning Electron Microscope coupled with an energy dispersive X-ray analyzer (SEM/EDX) revealed weathered MPs with chemical elements adhered to their surface (Cu, Fe, Mg, S, Cl, etc.). The results of this study recommend the use of D. trunculus as a new bioindicator of MPs pollution following an urban change in the coastal scenery. Also, a sustainable coastal management must be implemented in the study area.

To Waste or Not to Waste: Questioning Potential Health Risks of Micro- and Nanoplastics with a Focus on Their Ingestion and Potential Carcinogenicity

Micro- and nanoplastics (MNPs) are recognized as emerging contaminants, especially in food, with unknown health significance. MNPs passing through the gastrointestinal tract have been brought in context with disruption of the gut microbiome. Several molecular mechanisms have been described to facilitate tissue uptake of MNPs, which then are involved in local inflammatory and immune responses. Furthermore, MNPs can act as potential transporters ("vectors") of contaminants and as chemosensitizers for toxic substances ("Trojan Horse effect"). In this review, we summarize current multidisciplinary knowledge of ingested MNPs and their potential adverse health effects. We discuss new insights into analytical and molecular modeling tools to help us better understand the local deposition and uptake of MNPs that might drive carcinogenic signaling. We present bioethical insights to basically re-consider the "culture of consumerism." Finally, we map out prominent research questions in accordance with the Sustainable Development Goals of the United Nations.

Buy-now-pay-later: Hazards to human and planetary health from plastics production, use and waste

More than 8 billion tonnes of plastic were produced between 1950 and 2015, that is 1 tonne for every man, woman and child on our planet. Global plastic production has been growing exponentially with an annual growth rate of 8.4% since 1950, equating to approximately 380 million tonnes per annum. A further 50 kg of plastic is now being produced for each person every year with production continuing to accelerate. Here, we discuss the human and planetary health hazards of all that plastic. We consider each step in the journey of these complex and pervasive industrial materials: from their synthesis predominantly from fossil fuel feedstocks, through an often-brief consumer use as plastic products, and onto waste streams as fuel, permanent landfill or as unmanaged waste in our environment, food, air and bodies.

Spatial distribution of microplastics in the fluvial sediments of a transboundary river - A case study of the Tisza River in Central Europe

The geographical environment fundamentally influences the transport and deposition of sediments, including microplastics. In addition, the socioeconomic differences inherent in transboundary catchments result in various waste management strategies among the different countries influencing the input of microplastics into rivers. The catchment of the Tisza River in Central Europe is shared by five countries with different economic statuses and wastewater treatment practices. The aim of this research is to study the spatial changes in microplastic debris deposition along the Tisza and its main tributaries. The mean number of microplastic particles in the sediments of the Tisza was 3177 ± 1970 items/kg, while 3808 ± 1605 items/kg were counted in the sediments of the tributaries. Most of the particles were fibres, indicating the dominance of municipal wastewater input; this is especially the case in the upstream sub-catchments, where there are low degrees of wastewater management. The highest amount of microplastics was found in the sediments of the most-upstream section, where a low number of households are connected to wastewater treatment plants. Thus, it is hypothesized that suburban areas where high population densities and improper waste management co-exist may contribute to the direct input of microplastics into river systems and the development of local microplastic contamination hotspots. In addition, a high microplastic concentration was measured at the furthest downstream section, resulting from the decreased flow velocity related to impoundment by a dam. The efficiency of the microplastic trapping of the various depositionary forms varies along the river, suggesting various influencing factors and the complexity of the process. The higher concentration of microplastics observed in the tributaries compared to that observed in sediments of the main stream may reflect the importance of local sources and the complexity of source-to-sink relations for microplastic routes through the fluvial system; these processes do not always reflect progressive downstream increases.