Airborne microplastics detected in the lungs of wild birds in Japan

Microplastic contamination in threatened wild felids of India: Understanding environmental uptake, feeding implications, and associated risks

While the presence of microplastics (MPs, <5 mm) in various aquatic organisms is well-documented, studies on the accumulation of MPs in terrestrial predators remain limited worldwide, including in India. This study aims to evaluate, for the first time, the occurrence of MPs in the scat of mid-sized felids-fishing cat and jungle cat-from their overlapping habitat in the Gangetic Estuary of India. The risk assessment of MPs and management recommendation for MP mitigation was also discussed in this context. Notably, our study is the first to report the presence of MPs and mesoplastics in fishing cat from India and jungle cat globally. The abundance of MPs was found to be higher in jungle cat (12.6 ± 1.93 MP/g d.w) compared to fishing cat (10.5 ± 2.12 MP/g d.w) in the Gangetic estuary. Furthermore, fiber-shaped (70.37%) and 1-5 mm-sized (47.73%) MPs predominated in both felid species, while fiber bundles were observed only in jungle cat. Red-colored MPs (27.62%) were predominantly found in fishing cat, whereas transparent MPs (33.33%) were more common in jungle cat. Scanning electron microscopy revealed possible environmental and digestive degradation marks on the MPs. A total of seven synthetic and one natural polymer were identified, with Ethylene Vinyl Alcohol (55.56%) being predominant in fishing cat and Polyethylene (33.33%) more common in jungle cat. Polymer risk assessment indicated that the MPs in fishing cat fall into the danger category, Group IV (PHI 100-1000), while jungle cat possess high threat under extreme danger category, Group V (PHI >1000). The observed MPs and mesoplastics in felids probably come from adjacent environmental uptake and/or accumulate through trophic transfer from prey items. The evidence of MPs in felids may pose a threat to the big cat-Royal Bengal tigers in the Sundarbans. Therefore, various landscape-based policy implementations are recommended to mitigate MP pollution.

Effects of microplastics on energy accumulation in a migratory shorebird in the coastal wetlands of the Yellow Sea, China

Microplastic pollution has emerged as a significant environmental concern at the global level, potentially threatening biodiversity conservation and human wellbeing. As an important biological group with a wide global distribution, migratory shorebirds face considerable stress due to plastic and microplastic pollution. However, few studies have explored the ecotoxic impact of microplastic pollution on migratory shorebirds. To investigate the physiological effects of microplastic pollution on migratory shorebirds, this study obtained the morphological data of 79 dunlins at a key stopover site at the midpoint of the East Asian-Australasian Flyway in 2023 autumn. Meanwhile, fecal and blood samples were collected to examine the microplastic abundance accumulated in the body and metabolic levels. Microplastics were detected in 100 % of dunlins, comprising 12 distinct polymer types. The average abundance of microplastics ingested by dunlins was 134.50 items/g, which was higher than the reported abundance of environmental sediment. The present study confirmed that individuals with longer bills ingested more microplastics, resulting in significantly decreased body mass for the same shorebird. Compared to the low contamination group, metabolomic analysis also revealed that dunlins with elevated microplastic contamination exhibited the down-regulation of 10 metabolic pathways, including pyrimidine metabolism, beta-alanine metabolism, and vitamin C metabolism. The findings of this study underscore the potential threat microplastics pose to the health of migratory shorebirds. It is recommended that synergies be developed between microplastic management and biodiversity conservation at global and regional scales, with migratory birds serving as pivotal indicator species.

High microplastic pollution in birds of urban waterbodies revealed by non-invasively collected faecal samples

Plastic waste concentrates in aquatic environments, where wildlife can ingest or absorb it. In birds, plastic particles have been identified in hundreds of aquatic and terrestrial species leading to adverse effects. Most studies investigating microplastic pollution in birds use dead individuals or invasive techniques. However, microplastic ingestion can also be determined by analysing birds' faeces. There is a lack of information regarding microplastic pollution of birds inhabiting urban freshwaters, where very high pollution levels are expected. We analysed body condition of individual birds inhabiting freshwaters in the city of Münster (Germany) and microplastic contamination in their faeces. We found microplastic particles (mainly fibres) in all species (Mallard Anas platyrhynchos, Jack Snipe Lymnocryptes minimus, Black-headed Gull Chroicocephalus ridibundus and Common Moorhen Gallinula chloropus) and most samples (98 %). Microplastic pollution ranged from 0.26 to 72.03 particles per mg faeces. The observed microplastic pollution frequency and pollution levels were much higher compared to other studies of birds in freshwater environments, probably resulting from the high contamination of urban waters. We found no effect of the number of microplastic particles on body condition. As all investigated species are at least partially migratory, a long-distance transport of microplastic particles may increase the probability that migratory birds transport (and excrete) microplastic particles to remote locations that otherwise suffer from little anthropogenic pollution. We demonstrate that non-invasively collected faecal samples collected during bird ringing/banding can be used as indicators of microplastic pollution, and call for more studies investigating the effects of microplastics on birds - with a special focus on urban freshwaters.

Assessing microplastic and nanoplastic contamination in bird lungs: evidence of ecological risks and bioindicator potential

Microplastics (MPs, 1 µm-5 mm) and nanoplastics (NPs, < 1 µm), collectively termed micro(nano)plastics (MNPs), are pervasive airborne pollutants with significant ecological risks. Birds, recognized as bioindicators, are particularly vulnerable to MNP exposure, yet the extent and risks of MNP pollution in bird lungs remain largely unexplored. This study assessed MP exposure in bird lungs of 51 species and NP exposure in the lungs of five representative species using laser direct infrared (LDIR) and pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) techniques, respectively. The LDIR analysis revealed different degrees of MP contamination in bird lungs, with an average abundance of 221.20 items per species and 416.22 MP particles per gram of lung. Among 32 identified MP types, chlorinated polyethylene (CPE) and butadiene rubber (BR) predominated, with particles primarily in film and pellet forms, concentrated in the 20-50 μm size range. The polymer hazard index (PHI) indicated elevated ecological risks (levels Ⅲ or Ⅳ) in most bird lungs. Py-GC-MS detected nylon 66 (PA66), polyvinyl chloride (PVC), and polypropylene (PP) NPs at varying concentrations. Terrestrial, carnivorous, and larger-bodied birds exhibited higher MNP burdens. This study provides the first evidence of MNP contamination in bird lungs, highlighting their potential as bioindicators of airborne MNP pollution.

Identifying and analyzing the microplastics in human aqueous humor by pyrolysis-gas chromatography/mass spectrometry

Microplastics (MPs), an emerging global pollutant, pose potential risks to human health and have garnered increasing attention. Previous research has identified MPs in various human tissues and organs, but not in the aqueous humor of the eyes. This study used pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to explore MPs in aqueous humor. Five types of MPs-polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polyamide 66 (PA66), and polystyrene (PS)-were found, with PE and PVC being most common. PP was more prevalent in children, while PA66 was more common in adults. MPs abundance generally followed the trend: adults > children > elders among age groups, and females > males between gender groups. Notably, this study is the first to confirm MPs in human aqueous humor, providing a foundation for future research on their impact on intraocular health and enhancing our understanding of the MPs' body distribution.

Using feral pigeon (Columba livia) to monitor anthropogenic debris in urban areas: a case study in Taiwan's capital city

The terrestrial environment is a significant source of anthropogenic debris emissions. While most studies on anthropogenic debris focus on the marine environment, our research delves into the effects of human activity on anthropogenic debris ingestion by studying the carcasses of feral pigeons. From January to June 2022, we collected the gastrointestinal tracts (GI tracts) of 46 pigeon carcasses in Taipei, Taiwan's capital city. The results revealed that 224 anthropogenic debris samples were found, with the dominant form being fibers (71.9%), which are primarily black (29.9%). Fourier transform infrared spectroscopy (FTIR) revealed that the main component of anthropogenic debris is polyethylene (PE) (20.5%), followed by anthropogenic cellulose (19.2%) and various other plastics. This study revealed that the amount of anthropogenic debris and chemical composition in the GI tract significantly increase with increasing human activity. These results prove that feral pigeons are valuable indicators for monitoring anthropogenic debris pollution in urban ecosystems. On the other hand, past research focused on analyzing microplastics, but we confirmed that the GI tract of pigeons has a high proportion of anthropogenic cellulose. Importantly, future studies should consider the potential impacts of anthropogenic cellulose in terrestrial ecosystems, as this could have significant implications for ecosystem health.

Isolation and characterization of microplastics from the human respiratory system: Sputum, broncho-alveolar lavage fluid, and pleural fluid simultaneously

Microplastics (MPs) are emerging pollutants found in all ecosystems. While extensive research has focused on MP pollution across ecosystems, investigating their effect on the human body is still in its early stages. This study, conducted for the first time in Iran, specifically investigates MPs in the respiratory system, including sputum, broncho-alveolar lavage fluid (BALF), and pleural fluid. In this study, 34 patients participated after signing the consent form. Professional physicians collected 13 sputum samples, 11 BALF samples, and 10 pleural fluid samples. Patients' demographic information, lifestyle, occupation, exposed environment, and type of disease were evaluated through a questionnaire. The combination of digestion techniques, density separation, observation, Micro-Raman, and SEM/EDS analysis was performed to recognize MPs. The study results confirmed the presence of MPs in the respiratory system of all participants. MPs abundance in sputum, BALF, and pleural fluid varied between 156 and 468, 28-133, and 21-210 particles/100 mL, respectively. Generally, 22 types of MPs were identified and polyester (62-72%) was predominant. Fiber-shaped MPs were dominant in sputum (77%) and BALF (70%), and fragment-shaped in pleural fluid (63%). Particles <100 μm were the most abundant in all samples [in sputum (75.9%), BALF (50%), and pleural fluid (94.4%)]. Sampling type, occupational exposure, smoking, exposure to cigarette smoke, and wearing masks have affected the abundance of MPs (P < 0.05). Also, the shape and size of MPs affect their deposition in the respiratory system (P < 0.05). Hence, minimizing exposure to MPs is essential for safeguarding the environment and human health.

Comparison of lung disorders following intratracheal instillation of polystyrene microplastics with different surface functional groups

OBJECTIVES

Microplastics have been detected in the atmosphere, raising concerns about their impact on the lungs. There have been reports on the effects of surface functional groups in evaluating the physicochemical properties of microplastics, but no reports have evaluated their chronic effects. We performed intratracheal instillation in rats to evaluate the acute and chronic effects on the lungs of microplastics with different surface functional groups.

METHODS

Unmodified, NH2-modified, and COOH-modified polystyrene particles with a particle size of 1 μm were intratracheally instilled into the lungs of rats. Rats were dissected at 3 days, 1 week, 1 month, 3 months, and 6 months after exposure to analyze inflammatory cells and lung injury factors in bronchoalveolar lavage fluid (BALF) and to observe histopathological findings in the lungs.

RESULTS

A significant increase in the number of inflammatory cells in BALF was observed up to 1 week after exposure to the NH2-based modified polystyrene compared with the negative control group. A significant increase was observed 3 days after exposure, and histopathological findings in the lungs also showed an influx of inflammatory cells into the alveolar space in the acute phase, but not in the chronic phase. In in vitro studies using RAW cell lines, NH2-based modified polystyrene also induced the highest oxidative stress compared with unmodified and COOH-based modified polystyrene.

CONCLUSIONS

These results suggest that these polystyrenes do not have high pulmonary toxicity, although there are differences in toxicity due to differences in surface functional groups only in the acute phase.

Human-Caused High Direct Mortality in Birds: Unsustainable Trends and Ameliorative Actions

Human interaction with birds has never been more positive and supported by so many private citizens and professional groups. However, direct mortality of birds from anthropogenic causes has increased and has led to significant annual losses of birds. We know of the crucial impact of habitat loss on the survival of birds and its effects on biodiversity. Direct mortality via anthropogenic causes is an additive but biologically important cause of avian decline. This is the focus of this paper. This paper synthesises and interprets the data on direct anthropogenic causes of mortality in birds, and it also discusses emerging and relatively hidden problems, including new challenges that birds may not be able to manage. This paper points out that such deaths occur indiscriminately and have negative behavioural and reproductive consequences even for survivors. All of these factors are important to address, because any functional habitat depends on birds. This paper suggests that some of this death toll can be reduced substantially and immediately, even some of the seemingly intractable problems. This paper also proposes cross-disciplinary solutions, bearing in mind that "ecosystem services" provided by birds benefit us all, and that the continued existence of avian diversity is one cornerstone for human survival.

“Lung-on-a-chip” as an instrument for studying the pathophysiology of human respiration

“Lung-on-a-chip” (LoC) is a microfluidic device, imitating the gas-fluid interface of the pulmonary alveole in the human lung and intended for pathophysiological, pharmacological and molecular-biological studies of the air-blood barrier in vitro. The LoC device itself contains a system of fluid and gas microchannels, separated with a semipermeable elastic membrane, containing a polymer base and the alveolar cell elements. Depending on the type of LoC (single-, double- and three-channel), the membrane may contain only alveolocytes or alveolocytes combined with other cells — endotheliocytes, fibroblasts, alveolar macrophages or tumor cells. Some LoC models also include proteinic or hydrogel stroma, imitating the pulmonary interstitium. The first double-channel LoC variant, in which one side of the membrane contained an alveolocytic monolayer and the other side — a monolayer of endotheliocytes, was developed in 2010 by a group of scientists from the Harvard University for maximally precise in vitro reproduction of the micro-environment and biomechanics operations of the alveoli. Modern LoC modifications include the same elements and differ only by the construction of the microfluidic system, by the biomaterial of semipermeable membrane, by the composition of cellular and stromal elements and by specific tasks to be solved. Besides the LoC imitating the hematoalveolar barrier, there are modifications for studying the specific pathophysiological processes, for the screening of medicinal products, for modeling specific diseases, for example, lung cancer, chronic obstructive pulmonary disease or asthma. In the present review, we have analyzed the existing types of LoC, the biomaterials used, the methods of detecting molecular processes within the microfluidic devices and the main directions of research to be conducted using the “lung-on-a-chip”.

The whole life journey and destination of microplastics: A review

Recent reports indicate that ubiquitous microplastics (MPs) in the environment can infiltrate the human body, posing significant health risks and garnering widespread attention. However, public understanding of the intricate processes through which microplastics are transferred to humans remains limited. Consequently, developing effective strategies to mitigate the escalating issue of MPs pollution and safeguard human health is still challenging. In this review, we elucidated the sources and dynamic migration pathways of MPs, examined its complex interactions with other pollutants, and identified primary routes of human exposure. Subsequently, the events and alterations of gut microbiota, gut microbiota metabolism, and intestinal barrier after MPs enter the gut of organisms are unclosed. Additionally, it highlighted the ease with which MPs translocate from the intestine to other organs along with their biological toxicities. Finally, we also emphasized the knowledge gaps in the current research field and proposes future research directions. This review aims to enhance public awareness regarding microplastic pollution and provide valuable references for forthcoming research endeavors as well as policy formulation related to this pressing issue.

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.

First evidence of microplastic inhalation among free-ranging small cetaceans

Plastic is a ubiquitous environmental contaminant, resulting in widespread exposure across terrestrial and marine spaces. In the environment, plastics can degrade into microparticles where exposure has been documented in a variety of fauna at all trophic levels. Human epidemiological studies have found relationships between inhaled microplastics and oxidative stress and inflammation. Previous studies of bottlenose dolphins (Tursiops truncatus) have reported prevalent exposure to plasticizing chemicals (e.g., phthalates) as well as particle loads in gastrointestinal tracts, but exposure from inhalation has not yet been studied. The objective of this study was to determine if inhalation is a viable route of microplastic exposure for free-ranging dolphins. Exhalation samples were opportunistically collected from dolphins residing in Sarasota Bay, Florida (n = 5) and Barataria Bay, Louisiana (n = 6) during catch-and-release health assessments to screen for microplastic particles. All dolphin samples contained at least one suspected microplastic particle, and polymer composition was determined for 100% of a subset (n = 17) of samples. Additional studies are warranted to better understand the extent of inhaled microplastics, as well as to explore impacts, given potential risks to lung function and health.

The potential use of birds as bioindicators of suspended atmospheric microplastics and artificial fibers

Microplastics (MPs) and artificial fibers (AFs) have been detected suspended tens of meters above ground level in the atmosphere, yet empirical data on them remain scarce. This study aimed to investigate the presence of MPs and AFs in the digestive and respiratory systems of two abundant bird species, the Common House Martin (Delichon urbicum) and the Common Swift (Apus apus), within the Community of Madrid, Spain. Given that these birds spend the majority of their lives airborne, engaging in activities such as mating and sleeping during flight, the research sought to assess the potential of using these bird species as bioindicators for suspended atmospheric MPs and AFs. Samples were obtained from necropsies of birds (N = 24) collected primarily between spring and summer from 2021 to 2023. Only individuals that died within the initial 24-hour period and had not been fed were selected for examination to avoid contamination. MPs and AFS were identified by micro-FTIR, characterized and quantified. Results revealed that 75 % of the sampled birds exhibited at least one MPs in their respiratory and/or digestive system. All identified MPs were fibers, with polyester (PES) being the most predominant (48 %), followed by acrylic fibers (ACR; 28 %), and polyethylene (PE; 18 %). The average concentrations in the respiratory system were 1.12 ± 0.45 MPs/specimen and 2.78 ± 1.04 AFs/specimen for Common Swift and 0.75 ± 0.30 MPs/specimen and 0.75 ± 0.36 AFs/specimen for House Martin. In the digestive system, these were 1.92 ± 0.72 MPs/specimen and 3.42 ± 0.69 AFs/specimen for Common Swift, and 1.34 ± 0.50 MPs/specimen and 1.39 ± 0.47 AFs/specimen for House Martin. Birds collected areas with high population density located in the direction of the prevailing winds showed a concentration of MPs significantly higher in the digestive system. Taken together, these findings confirmed the potential use of these birds as bioindicators for monitoring of suspended atmospheric MPs and AFs.

Contamination of coastal and marine bird species with plastics: Global analysis and synthesis

This review article provides an account of coastal and marine bird species contaminated with plastics in light of ingestion, taxonomy, feeding clusters, types, shapes, colours and lethal and sublethal effects. Bird species were found contaminated with plastics in 39 locations/countries across the seven continents. Global analysis shows that low, medium and high plastic ingestion occurred in bird species across the globe. Fulmars, shearwaters, petrels, albatrosses, gulls, and kittiwakes (all marine/seabirds) were found contaminated with plastics in several locations in the world. Bird species belonging to the Procellariidae, Laridae, Diomedeidae (by taxonomy), piscivorous, molluscivorous, and cancrivorous (by feeding habits) were most contaminated with plastics. Microplastic, mesoplastic and macroplastic (by sizes), PP, PE, PS, PET, PAN and PVC (by types), fragments, pellets, fibres, foams, sheets, threads, fishing lines and films (by shapes) and white, blue, green, black, clear, red and yellow (by colours) were the most common plastics ingested by birds. Several bird species contaminated with plastics fall within the critically endangered, endangered and vulnerable categories. The ingestion of plastics can cause direct harm to birds resulting in death. In addition, plastic-derived toxic chemical additives and plastic-adsorbed toxic chemicals would be an additional stressor causing both lethal and sublethal effects that can cause greater harm to the health of birds. Several measures are suggested to reduce plastic pollution in the environment to safeguard birds and the environment.

Investigation of pulmonary inflammatory responses following intratracheal instillation of and inhalation exposure to polypropylene microplastics

BACKGROUND

Microplastics have been detected in the atmosphere as well as in the ocean, and there is concern about their biological effects in the lungs. We conducted a short-term inhalation exposure and intratracheal instillation using rats to evaluate lung disorders related to microplastics. We conducted an inhalation exposure of polypropylene fine powder at a low concentration of 2 mg/m3 and a high concentration of 10 mg/m3 on 8-week-old male Fischer 344 rats for 6 h a day, 5 days a week for 4 weeks. We also conducted an intratracheal instillation of polypropylene at a low dose of 0.2 mg/rat and a high dose of 1.0 mg/rat on 12-week-old male Fischer 344 rats. Rats were dissected from 3 days to 6 months after both exposures, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected to analyze lung inflammation and lung injury.

RESULTS

Both exposures to polypropylene induced a persistent influx of inflammatory cells and expression of CINC-1, CINC-2, and MPO in BALF from 1 month after exposure. Genetic analysis showed a significant increase in inflammation-related factors for up to 6 months. The low concentration in the inhalation exposure of polypropylene also induced mild lung inflammation.

CONCLUSION

These findings suggest that inhaled polypropylene, which is a microplastic, induces persistent lung inflammation and has the potential for lung disorder. Exposure to 2 mg/m3 induced inflammatory changes and was thought to be the Lowest Observed Adverse Effect Level (LOAEL) for acute effects of polypropylene. However, considering the concentration of microplastics in a real general environment, the risk of environmental hazards to humans may be low.

Plastic breath: Quantification of microplastics and polymer additives in airborne particles

The widespread extensive use of synthetic polymers has led to a substantial environmental crisis caused by plastic pollution, with microplastics detected in various environments and posing risks to both human health and ecosystems. The possibility of plastic fragments to be dispersed in the air as particles and inhaled by humans may cause damage to the respiratory and other body systems. Therefore, there is a particular need to study microplastics as air pollutants. In this study, we tested a combination of analytical pyrolysis, gas chromatography-mass spectrometry, and gas and liquid chromatography-mass spectrometry to identify and quantify both microplastics and their additives in airborne particulate matter and settled dust within a workplace environment: a WEEE treatment plant. Using this combined approach, we were able to accurately quantify ten synthetic polymers and eight classes of polymer additives. The identified additives include phthalates, adipates, citrates, sebacates, trimellitates, benzoates, organophosphates, and newly developed brominated flame retardants.

Birds as bioindicators of plastic pollution in terrestrial and freshwater environments: A 30-year review

Plastic pollution is a global concern that has grown ever more acute in recent years. Most research has focused on the impact of plastic pollution in marine environments. However, plastic is increasingly being detected in terrestrial and freshwater environments with key inland sources including landfills, where it is accessible to a wide range of organisms. Birds are effective bioindicators of pollutants for many reasons, including their high mobility and high intra- and interspecific variation in trophic levels. Freshwater and terrestrial bird species are under-represented in plastic pollution research compared to marine species. We reviewed 106 studies (spanning from 1994 onwards) that have detected plastics in bird species dwelling in freshwater and/or terrestrial habitats, identifying knowledge gaps. Seventy-two studies focused solely on macroplastics (fragments >5 mm), compared to 22 microplastic (fragments <5 mm) studies. A further 12 studies identified plastics as both microplastics and macroplastics. No study investigated nanoplastic (particles <100 nm) exposure. Research to date has geographical and species' biases while ignoring nanoplastic sequestration in free-living freshwater, terrestrial and marine bird species. Building on the baseline search presented here, we urge researchers to develop and validate standardised field sampling techniques and laboratory analytical protocols such as Raman spectroscopy to allow for the quantification and identification of micro- and nanoplastics in terrestrial and freshwater environments and the species therein. Future studies should consistently report the internalised and background concentrations, types, sizes and forms of plastics. This will enable a better understanding of the sources of plastic pollution and their routes of exposure to birds of terrestrial and freshwater environments, providing a more comprehensive insight into the potential impacts on birds.

Accumulation of microplastics in predatory birds near a densely populated urban area

The pollution due to plastic and other anthropogenic particles has steadily increased over the last few decades, presenting a significant threat to the environment and organisms, including avian species. This research aimed to investigate the occurrence of anthropogenic pollutants in the digestive and respiratory systems of four birds of prey: Common Buzzard (Buteo buteo), Black Kite (Milvus migrans), Eurasian Sparrowhawk (Accipiter nisus), and Northern Goshawk (Accipiter gentilis). The results revealed widespread contamination in all species with microplastics (MPs) and cellulosic anthropogenic fibers (AFs), with an average of 7.9 MPs and 9.2 AFs per specimen. Every digestive system contained at least one MP, while 65 % of specimens exhibited MPs in their respiratory systems. This is the work reporting a high incidence of MPs in the respiratory system of birds, clearly indicating inhalation as a pathway for exposure to plastic pollution. The content of MPs and AFs varied significantly when comparing specimens collected from central Madrid with those recovered from other parts of the region, including rural environments, suburban areas, or less populated cities. This result aligns with the assumption that anthropogenic particles disperse from urban centers to surrounding areas. Additionally, the dominant particle shape consisted of small-sized fibers (> 98 %), primarily composed of polyester, polyethylene, acrylic materials, and cellulose fibers exhibiting indicators of industrial treatment. These findings emphasize the necessity for further research on the impact of plastic and other anthropogenic material contamination in avian species, calling for effective strategies to mitigate plastic pollution.

Microplastics induced inflammation in the spleen of developmental Japanese quail (Coturnix japonica) via ROS-mediated p38 MAPK and TNF signaling pathway activation1

Microplastics (MPs) have been found in virtually every environment on earth and become a source of pollution around the world. The toxicology of microplastics on immunity is an emerging area of research, and more studies are needed to fully understand the effects of microplastics exposure on animal health. Therefore, we tried to determine the immunotoxic effects of microplastics on avian spleen by using an animal model- Japanese quail (Coturnix japonica). One-week chicks were exposed to environmentally relevant concentrations of 0.02 mg/kg, 0.4 mg/kg and 8 mg/kg polystyrene microplastics in the feed for 5 weeks. The results demonstrated that microplastics induced microstructural injuries featured by cell disarrangement and vacuolation indicating splenic inflammation. Ultrastructural damages including membrane lysis and mitochondrial vacuolation also suggested inflammatory responses in the spleen by microplastics exposure. Meanwhile, increasing reactive oxygen species (ROS) and Malondialdehyde (MDA) while the inactivation of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) indicated oxidative stress in the spleen. Moreover, the increasing level of proinflammatory cytokines including Tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interleukin-1β (IL-1β), interleukin-6 (IL-6) and decreasing level of anti-inflammatory cytokine interleukin-10 (IL-10) implied splenic inflammation. Furthermore, transcriptomic analysis showed that microplastics induced inflammatory responses in the spleen through p38 mitogen-activated protein kinases (p38 MAPK) pathway activation and tumor necrosis factor (TNF) signaling stimulation. The signaling stimulation also aggravated cell apoptosis in the spleen. The present study may benefit to understand potential mechanisms of developmental immunotoxicology of microplastics.

Mitigative potential of kaempferide against polyethylene microplastics induced testicular damage by activating Nrf-2/Keap-1 pathway

Polyethylene microplastics (PE-MPs) are one of the environmental contaminants that instigate oxidative stress (OS) in various organs of the body, including testes. Kaempferide (KFD) is a plant-derived natural flavonol with potential neuroprotective, hepatoprotective, anti-cancer, anti-oxidant and anti-inflammatory properties. Therefore, the present study was designed to evaluate the alleviative effects of KFD against PE-MPs-prompted testicular toxicity in rats. Fourty eight adult male albino rats were randomly distributed into 4 groups: control, PE-MPs-administered (1.5 mgkg-1), PE-MPs (1.5 mgkg-1) + KFD (20 mgkg-1) co-treated and KFD (20 mgkg-1) only treated group. PE-MPs intoxication significantly (P < 0.05) lowered the expression of Nrf-2 and anti-oxidant enzymes, while increasing the expression of Keap-1. The activities of anti-oxidants i.e., catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD), hemeoxygene-1 (HO-1) and glutathione peroxidase (GPx) were reduced, besides malondialdehyde (MDA) and reactive oxygen species (ROS) contents were increased significantly (P < 0.05) following the PE-MPs exposure. Moreover, PE-MPs exposure significantly (P < 0.05) reduced the sperm motility, viability and count, whereas considerably (P < 0.05) increased the dead sperm number and sperm structural anomalies. Furthermore, PE-MPs remarkably (P < 0.05) decreased steroidogenic enzymes and Bcl-2 expression, while increasing the expression of Caspase-3 and Bax. PE-MPs exposure significantly (P < 0.05) reduced the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, whereas inflammatory indices were increased. PE-MPs exposure also induced significant histopathological damages in the testes. Nevertheless, KFD supplementation significantly (P < 0.05) abrogated all the damages induced by PE-MPs. The findings of our study demonstrated that KFD could significantly attenuate PE-MPs-instigated OS and testicular toxicity, due to its anti-oxidant, anti-inflammatory, androgenic and anti-apoptotic potential.

Airborne microplastics: A narrative review of potential effects on the human respiratory system

There has been growing evidence showing the widespread of airborne microplastics (AMPs) in many regions of the world, raising concerns about their impact on human health. This review aimed to consolidate recent literature on AMPs regarding their physical and chemical characteristics, deposition in the human respiratory tract, translocation, occurrence from human studies, and toxic effects determined in vitro and in vivo. The physical characteristics influence interactions with cell membranes, cellular internalization, accumulation, and cytotoxicity resulting from cell membrane damage and oxidative stress. In addition, prolonged exposure to AMP-associated toxic chemicals might lead to significant health effects. Most toxicological assessments of AMPs in vitro and in vivo have demonstrated that oxidative stress and inflammation are major mechanisms of action for their toxic effects. Elevated reactive oxygen species production could lead to mitochondrial dysfunction, inflammatory responses, and subsequent apoptosis in experimental models. To date, there has been some evidence suggesting exposure in humans. However, the data are still insufficient, and adverse human health effects need to be investigated. Future research on the existence, exposure, and health effects of AMPs is required for developing preventive and mitigation measures to protect human health.

Approach to an answer to "How dangerous microplastics are to the human body": A systematic review of the quantification of MPs and simultaneously exposed chemicals

This review aims to facilitate future research on microplastics (MPs) in the environment using systematic and analytical protocols, ultimately contributing to assessment of the risk to human health due to continuous daily exposure to MPs. Despite extensive studies on MP abundance in environment, identification, and treatment, their negative effects on human health remain unknown due to the lack of proof from clinical studies and limited technology on the MP identification. To assess the risk of MPs to human health, the first step is to estimate MP intake via ingestion, inhalation, and dermal contact under standardized exposure conditions in daily life. Furthermore, rather than focusing on the sole MPs, migrating chemicals from plastic products should be quantified and their health risk be assessed concurrently with MP release. The critical factors influencing MP release and simultaneously exposed chemicals (SECs) must be investigated using a standardized identification method. This review summarises release sources, factors, and possible routes of MPs from the environment to the human body, and the quantification methods used in risk assessment. We also discussed the issues encountered in MP release and SEC migration. Consequently, this review provides directions for future MP studies that can answer questions about MP toxicity to human health.

Application of Pattern Recognition and Computer Vision Tools to Improve the Morphological Analysis of Microplastic Items in Biological Samples

Since, in many routine analytical laboratories, a stereomicroscope coupled with a digital camera is not equipped with advanced software enabling automatic detection of features of observed objects, in the present study, a procedure of feature detection using open-source software was proposed and validated. Within the framework of applying microscopic expertise coupled with image analysis, a set of digital images of microplastic (MP) items identified in organs of fish was used to determine shape descriptors (such as length, width, item area, etc.). The edge points required to compute shape characteristics were set manually in digital images acquired by the camera coupled with a binocular, and respective values were computed via the use of built-in MotiConnect software. As an alternative, a new approach consisting of digital image thresholding, binarization, the use of connected-component labeling, and the computation of shape descriptors on a pixel level via using the functions available in an OpenCV library or self-written in C++ was proposed. Overall, 74.4% of the images were suitable for thresholding without any additional pretreatment. A significant correlation was obtained between the shape descriptors computed by the software and computed using the proposed approach. The range of correlation coefficients at a very high level of significance, according to the pair of correlated measures, was higher than 0.69. The length of fibers can be satisfactorily approximated using a value of half the length of the outer perimeter (r higher than 0.75). Compactness and circularity significantly differ for particles and fibers.

Sentinel supervised lung-on-a-chip: A new environmental toxicology platform for nanoplastic-induced lung injury

Nanoplastics are prevalent in the air and can be easily inhaled, posing a threat to respiratory health. However, there have been few studies investigating the impact of nanoplastics on lung injury, especially chronic obstructive pulmonary disease (COPD). Furthermore, cell and animal models cannot deeply understand the pollutant-induced COPD. Existing lung-on-a-chip models also lack interactions among immune cells, which are crucial in monitoring complex responses. In the study, we built the lung-on-a-chip to accurately recapitulate the structural features and key functions of the alveolar-blood barrier while integrating multiple immune cells. The stability and reliability of the lung-on-a-chip model were demonstrated by toxicological application of various environmental pollutants. We Further focused on exploring the association between COPD and polystyrene nanoplastics (PS-NPs). As a result, the cell viability significantly decreased as the concentration of PS-NPs increased, while TEER levels decreased and permeability increased. Additionally, PS-NPs could induce oxidative stress and inflammatory responses at the organ level, and crossed the alveolar-blood barrier to enter the bloodstream. The expression of α1-antitrypsin (AAT) was significantly reduced, which could be served as early COPD checkpoint on the lung-chips. Overall, the lung-on-a-chip provides a new platform for investigating the pulmonary toxicity of nanoplastics, demonstrating that PS-NPs can harm the alveolar-blood barrier, cause oxidative damage and inflammation, and increase the risk of COPD.