The global threat from plastic pollution

Insights into the effects of aging on the combined toxicity of polystyrene nanoplastics and chlordane against Caenorhabditis elegans

Nanoplastics are emerging contaminants that may co-exist with organochlorine pesticides and adversely affect invertebrates in the environment. However, the impact of environmental aging on the combined toxicity of nanoplastics and organochlorine pesticides remains unclear. This study investigated the effects of aging on the combined toxicity of polystyrene nanoplastics (PS NPs) and chlordane against Caenorhabditis elegans. The results showed that photo-aging altered the physicochemical properties of PS NPs and promoted the combined toxicity of PS NPs and chlordane to nematodes by reducing survival rate, body length and enhancing germline apoptosis. Additionally, combined exposure of nematodes to aged PS NPs and chlordane significantly increased reactive oxygen species production and intestinal permeability, suggesting that aging enhances combined toxicity through oxidative stress and intestinal damage. Moreover, aging increased chlordane contents in nematodes without promoting PS NPs accumulation, potentially leading to increased combined toxicity of PS NPs and chlordane. Notably, aging significantly increased the accumulation of PS NPs in the posterior intestine of the nematode during co-exposure, which may be responsible for the most sensitive and highest degree of change in germline apoptosis. These observations emphasize the significance of accounting for environmental aging as well as the accumulation and distribution of nanoplastics in organisms when assessing the combined effects of nanoplastics and coexisting pollutants.

Impacts and transport of microplastics: Population dynamics in frogs and the transfer between aquatic and terrestrial ecosystems

Increased plastic production has led to severe environmental issues, with microplastics (MPs) becoming widespread contaminants. Amphibians, particularly frogs, are crucial bioindicators because of their permeable skin and biphasic life cycles, making them highly vulnerable to pollutants. This study examined the effects of MPs on Dryophytes japonicus, focusing on hatching, survival, growth, and metamorphosis. We also explored how frogs facilitate the transfer of MPs from aquatic to terrestrial environments. Using an individual-based modeling (IBM) approach, nine male-female pairs were observed in controlled breeding environments. Survival probabilities were analyzed using Kaplan-Meier estimates, and population dynamics were simulated for over 20 years under varying resource conditions. The results demonstrated significantly lower survival rates in the MP-exposed groups. Simulations indicated that exposed populations declined continuously under resource limitation, whereas MP transfer was the highest under high-density, resource-rich conditions. The control groups had larger populations, but were more vulnerable to extinction, whereas the treatment groups showed resilience to resource stress. Frogs may act as vectors, spreading MPs into terrestrial ecosystems, and contributing to soil contamination and trophic disruption. To mitigate these effects, conservation strategies such as habitat restoration, pollution control, and disease management are essential for preserving amphibian populations and ecosystem balance.

Degradation of biodegradable plastic films in soil: microplastics formation and soil microbial community dynamics

Biodegradable plastic poly(butylene adipate-co-terephthalate) (PBAT) has raised concerns regarding the release of PBAT microplastics and their potential environmental risks. In this study, PBAT plastic films were incubated in soil for 180 days to investigate the temporal evolution of PBAT microplastics and the dynamic responses of soil bacteria and fungi. The results showed that PBAT microplastics initially increased to a peak before decreasing by 74.7 % within 180 days. The predominant microplastics were film-shaped and smaller than 10 μm. Based on the temporal patterns, three distinct phases were identified: the initial release phase (0-30 days), the critical release phase (60-120 days), and the critical degradation phase (150-180 days). Notably, dominant fungal biomarkers with prevalent saprotrophic functions, particularly Humicola and Schizothecium, promoted the formation of PBAT microplastics by structurally fragmenting the PBAT film. In contrast, dominant bacterial biomarkers associated with dominant metabolic functions, such as Verrucomicrobiota, primarily contributed to the degradation of the PBAT microplastics by utilizing them as carbon sources. Our findings offer new insights into systematically evaluating the environmental behavior and potential environmental risks of biodegradable microplastics and provide a theoretical basis for strategies aimed at accelerating the degradation of biodegradable microplastics in soil environments.

Dynamic responses of soil microbial communities to long-term co-contamination with PBAT and cadmium

The co-contamination of plastics and heavy metals poses novel challenges to agricultural soil ecosystems. However, research into the long-term effects of such co-contamination on soil microbial communities remains limited. This study, through a 540-day incubation experiment, investigated the impacts of poly(butylene adipate-co-terephthalate) (PBAT) and cadmium (Cd) co-contamination on the structure and function of soil microbial communities. The findings revealed that co-contamination significantly altered soil nitrate and ammonium nitrogen levels. Furthermore, the co-contamination continuously and significantly reduced bacterial diversity, producing a more pronounced negative impact compared to single pollution. Key microbial groups such as Proteobacteria, acting as core microorganisms, were significantly enriched under co-contamination conditions, with their relative abundance increasing significantly by 40.0 %. This indicates their potential role in plastic degradation and heavy metal resistance. In addition, the co-contamination also drove the shift of bacterial and fungal community assembly from deterministic processes to stochastic processes. These insights not only fill the research gap regarding the effects of long-term co-contamination on soil microorganisms but also provide a scientific foundation for the development of targeted soil management and remediation strategies, especially in regions where plastic and heavy metal pollution coexist.

Biodegradation and bioaugmentation of the co-contamination of chloramphenicol and microplastics by Exiguobacterium sp. CAP4 isolated from a contaminated plastisphere

Microplastics (MPs) and antibiotics are newly emerging contaminants that have heavily accumulated in the environment and are a great cause of concern due to their co-contamination. Although the removal and degradation of individual MPs and antibiotics have been studied in various environments, our understanding of how to eliminate the co-contamination of MPs and antibiotics remains poor. In this study, the biodegradation of both micro polyethylene (mPE) and chloramphenicol (CAP) was analyzed in a wastewater sample. Members of the genera Exiguobacterium, Methanospirillum, Methanosaeta, and Candidatus Nitrocosmicus were proposed as biomarkers in plastisphere, which may contribute to the biodegradation of both contaminants. Notably, Exiguobacterium sp. CAP4 was isolated from the plastisphere and exhibited a high potential to degrade both CAP and mPE. Bioaugmentation with Exiguobacterium sp. CAP4 in mPEs and CAP contaminated wastewater facilitated the biodegradation of both mPE and CAP. This work expands the knowledge base regarding the simultaneous elimination of MPs and antibiotics in situ and identifies a promising bacterial strain for both MP and antibiotic biodegradation.

Improved neural networks for the classification of microplastics via inferior quality Raman spectra

Machine learning algorithms are proficient in the rapid extraction of features for the classification of microplastic Raman spectra. Nevertheless, the classification of Raman spectra from microplastics, particularly in the presence of complex environmental interference, remains a substantial challenge. In this study, an improved ResNet model incorporating the Squeeze-and-Excitation (SE) module is employed for the classification and identification of Raman spectra of microplastics across varying quality levels under diverse experimental conditions with insufficient laser power and short spectrum acquisition time. The improved ResNet model exhibits superior accuracy in classifying inferior quality Raman spectra characterized by significant noise and low signal-to-noise ratios, as compared to traditional CNN, without a considerable escalation in parameter size or computational burden. Even under the most adverse experimental conditions assessed, the model achieved a notable recognition accuracy of 97.83 %. Moreover, the application of Grad-CAM visualization provides insights into the criteria underlying machine learning-based spectral classification. This research underscores the capacity of machine learning algorithms in the analysis and interpretation of inferior quality Raman spectra within complex and non-ideal experimental scenarios.

Impact of microplastic concentration on soil nematode communities on the Qinghai-Tibet Plateau: Evidence from a field-based microcosms experiment

Microplastics are an emerging pollutant that poses a threat to local ecosystems. Recent studies have revealed that microplastics have penetrated the Qinghai-Tibetan Plateau. While previous studies have investigated the migration and distribution of microplastics and their effects on soil properties, their effects on soil fauna communities remain underexplored. Here, we conducted a 1-year microplastic addition experiment to evaluate the responses of soil nematode communities and employed piecewise structural equation modeling to disentangle the direct and indirect effects of microplastics on these communities. We found that: (1) nematode abundance, diversity, and metabolic footprints exhibited a hump-shaped response to microplastic treatments, peaking at the 0.1 % treatment; (2) nematode biomass was significantly affected by microplastics, with the lowest biomass observed at the 10 % treatment; (3) the direct effects of microplastics on nematode abundance outweighed indirect effects, particularly influencing fungivores and omnivorous nematodes; (4) although microplastics did not significantly alter energy flow within nematode communities, the relationship between the energy flow of fungivores and omnivorous was stronger than those among other trophic groups. Our study offers insights on microplastics' impact on nematode communities and their varied responses to microplastic concentrations, crucial for understanding ecological effects on soil ecosystems.

Microbial degradation of polypropylene microplastics and concomitant polyhydroxybutyrate production: An integrated bioremediation approach with metagenomic insights

The persistence of plastics, particularly polypropylene (PP), and their conversion into microplastics (MPs), specifically PP-MPs, have emerged as serious ecological threats to soil and aquatic environments. In the present study, we aimed to isolate a microbial consortium capable of degrading PP-MPs. The results revealed that three microbial consortia (CPP-KKU1, CPP-KKU2, and CPP-KKU3) exhibited the ability to degrade PP-MPs, achieving weight losses ranging from 11.6 ± 0.2 % to 17.8 ± 0.5 % after 30 days. Fourier transform infrared (FTIR) spectroscopy analysis confirmed the degradation through oxidation, as evidenced by the presence of new functional groups (-OH and -C=O). In particular, CPP-KKU3 showed the highest degradation efficiency, with scanning electron microscopy (SEM) analysis revealing surface cracking after treatment. Additionally, gas chromatography-mass spectrometry (GC-MS) analysis identified various intermediate compounds, including heterocyclic aromatic compounds, phenyl groups, methylthio derivatives, and ethoxycarbonyl derivatives, indicating complex biochemical processes that were likely mediated by microbial enzymes. Furthermore, polyhydroxybutyrate (PHB) production by these consortia was also investigated. The result showed that both CPP-KKU2 and CPP-KKU3 successfully produced PHB, with CPP-KKU3 demonstrating superior performance in terms of PP-MP degradation and PHB production. Metagenomic analysis of CPP-KKU3 revealed abundant carbohydrate-active enzymes (CAZymes), particularly glycosyl transferases and glycoside hydrolases, which are associated with MP digestion. This study presents a promising bioremediation approach that addresses plastic waste degradation and sustainable bioplastic production, offering a potential solution for environmental plastic pollution.

Cellular internalization pathways of environmentally exposed microplastic particles: Phagocytosis or macropinocytosis?

Microplastic particles (MP) ubiquitously occur in all environmental compartments where they interact with biomolecules, forming an eco-corona on their surfaces. The eco-corona affects the surface properties of MP and consequently how they interact with cells. Proteins, an integral component within the eco-corona, may serve as a ligand driving the interaction of MP with membrane receptors. To date, it is not known, whether eco-coronae originating from different environmental media differ in their proteinaceous compositions and whether these particles interact differently with cells. We show that the protein composition of the eco-coronae formed in freshwater (FW) and salt water (SW) are distinct from each other. We did not observe different adhesion strengths between MP coated with different eco-coronae and cells. However, the internalization efficiency and the underlying internalization mechanisms significantly differed between FW- and SW eco-coronae. By inhibiting actin-driven and receptor-mediated internalization processes using Cytochalasin-D, Amiloride, and Amantadine, we show that FW microplastic particles predominantly become internalized via phagocytosis, while macropinocytosis is more important for SW microplastic particles. Overall, our findings show that the origin of eco-coronae coatings are important factors for the cellular internalization of microplastic particles. This highlights the relevance of eco-coronae for adverse effects of environmentally relevant microplastic particles on cells and organisms.

Nanoplastics and microplastics released from an enzyme-embedded biodegradable polyester during hydrolysis

Embedding enzyme in biodegradable polyester accelerates hydrolysis in environments it ends up, but the release of microplastics (MPs) and nanoplastics (NPs) during this process remains underexplored. This work investigated the evolution of MPs and NPs released from poly(ε-caprolactone) (PCL) with embedded Lipase PS. The embedded enzyme significantly accelerated hydrolysis, causing the PCL film to disappear within 96 h. Notably, the formation rates and quantities of MPs and NPs were much higher compared to film with external enzyme. At 96 h, MPs (3.55 ×105 particles/mL) was 2.4 times, and NPs (4.65 ×107 particles/mL) was an order of magnitude higher than that with external enzyme. After 130 days, although both quantities and average size of MPs and NPs decreased due to only 90.6 % of enzymes were detected leaking, they did not completely disappear. The quantities of MPs and NPs were comparable to that with external enzyme, and the average size of MPs remained 1 μm. The simultaneous erosion inside film macroscopically, and severe chain cleavage microscopically, contributed to feasible film disintegration and formation of high amounts MPs and NPs. These findings underscore the importance of managing the release of MPs and NPs during the hydrolysis of enzyme-embedded biodegradable polyesters to ensure safety and mitigate environmental impact.

Plastic additives alter the influence of photodegradation on biodegradation of polyethylene/polypropylene polymers in natural rivers

The biodegradation of microplastics in river sediments was subject to the prior photodegradation in surface water and can be greatly affected by polymers and additives. However, the understanding of the effects of additives on the cascade photo- and biodegradation processes remains limited. In this study, the characteristics of morphology, functional groups, and indictive degrading bacteria of polyethylene (PE) and polypropylene (PP) were detected to analyze the effects of Dioctyl phthalate (DOP), Bisphenol A (BPA) and Benzotriazole (BTA), on the single and cascade photo- and biodegradation processes of PP/PE films (PP/PEP, PP/PEB, PP/PEPB). The results showed that photodegradation enhanced the biodegradation, by creating smaller fractions which induced the proliferation of new PP/PE-degrading bacteria (P-bacteria). Compared to the general PP/PE-degrading bacteria, P-bacteria displayed higher standard betweenness centrality and carbon metabolism. Among the three additives, DOP most obviously promoted photo- and biodegradation processes, followed by BPA. BTA inhibited the photodegradation to biodegradation by absorbing UV light. Overall, these findings provide insights into the nonnegligible joint influence of photodegradation and additives on the biodegradation of PP/PE resins in natural rivers.

Targeted conversion of waste PET into dimethyl terephthalate and ethylene carbonate under metal-free conditions

Ionic liquid-catalyzed methanolysis emerges as an efficient technique for transforming PET into premium-grade dimethyl terephthalate (DMT). However, incomplete depolymerization remains a major obstacle to the further industrial application of IL-catalyzed PET methanolysis. The proposed method utilized dimethyl carbonate (DMC) as the solvent for the complete methanolysis of waste PET under mild conditions, resulting in pure DMT and ethylene carbonate (EC) within 2.5 ​h. The use of 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) as the IL catalyst significantly enhanced the reaction efficiency. Spectroscopic analyses using 1H NMR and FT-IR confirmed the pivotal role of [EMIm][OAc] in establishing multiple hydrogen bonds with the reactants (PET, DMC, and MeOH) and the intermediate [ethylene glycol (EG)] during the catalytic process. This catalytic system exhibited remarkable performance, achieving complete conversion of PET, which resulted in the production of DMT and EC with yields of 99% and 91%, respectively. Moreover, this versatile approach is applicable to the upcycling of a wide variety of commercial polyesters and polycarbonates, underscoring its potential as a comprehensive solution for plastic waste management.

Drivers of environmental debris in metropolitan areas: A continental scale assessment

Plastic pollution is rapidly increasing, with land-based sources being the major contributors. Understanding the factors driving waste movement from land to sea is crucial for reducing leakage to the environment and its subsequent impact. In 2023 we conducted a stratified survey of mismanaged waste in the environment across six Australian metropolitan regions, covering inland, riverine, and coastal habitats, to determine a national baseline of debris in the environment. We completed 1907 transects, and found average debris density was 0.15 items m-2. Debris quantity was patchy and typically higher in areas with intensive land use, such as urban and agricultural zones, and socio-economically disadvantaged regions. Polystyrene (24 % of fragments) and cigarette butts (20 % of whole items) were the most common debris types. Most items could be identified by material type but not by specific use (e.g. unknown hard plastic fragments were found in 28 % of all transects). Comparing our coastal results to a survey from 10 years prior, we found a significant 39 % decrease in the national mean coastal debris density, and a 16 % increase in transects where no debris was found. Our study finds evidence to support how historical policies, practices, outreach campaigns, clean-up efforts and local custodianship have contributed to reducing debris in metropolitan coastal habitats. This national baseline study offers a benchmark to evaluate the effectiveness of new policies, practices, and awareness campaigns.

Charged polystyrene microplastics inhibit uptake and transformation of 14C-triclosan in hydroponics-cabbage system

INTRODUCTION

Since the outbreak of COVID-19, microplastics (MPs) and triclosan in pharmaceuticals and personal care products (PPCPs) are markedly rising. MPs and triclosan are co-present in the environment, but their interactions and subsequent implications on the fate of triclosan in plants are not well understood.

OBJECTIVE

This study aimed to investigate effects of charged polystyrene microplastics (PS-MPs) on the fate of triclosan in cabbage plants under a hydroponic system.

METHODS

14C-labeling method and liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (LC-QTOF-MS) analysis were applied to clarify the bioaccumulation, distribution, and metabolism of triclosan in hydroponics-cabbage system. The distribution of differentially charged PS-MPs in cabbage was investigated by confocal laser scanning microscopy and scanning electron microscopy.

RESULTS

The results showed that MPs had a significant impact on bioaccumulation and metabolism of triclosan in hydroponics-cabbage system. PS-COO-, PS, and PS-NH3+ MPs decreased the bioaccumulation of triclosan in cabbage by 69.1 %, 81.5 %, and 87.7 %, respectively, in comparison with the non-MP treatment (control). PS-MPs also reduced the translocation of triclosan from the roots to the shoots in cabbage, with a reduction rate of 15.6 %, 28.3 %, and 65.8 % for PS-COO-, PS, and PS-NH3+, respectively. In addition, PS-NH3+ profoundly inhibited the triclosan metabolism pathways such as sulfonation, nitration, and nitrosation in the hydroponics-cabbage system. The above findings might be linked to strong adsorption between PS-NH3+ and triclosan, and PS-NH3+ may also potentially inhibit the growth of cabbage. Specially, the amount of triclosan adsorbed on PS-NH3+ was significantly greater than that on PS and PS-COO-. The cabbage biomass was reduced by 76.9 % in PS-NH3+ groups, in comparison with the control.

CONCLUSION

The uptake and transformation of triclosan in hydroponics-cabbage system were significantly inhibited by charged PS-MPs, especially PS-NH3+. This provides new insights into the fate of triclosan and other PPCPs coexisted with microplastics for potential risk assessments.

Isolation of a novel microplastic-degrading bacterial strain: a promising agent for low-density polyethylene remediation

This study investigates the biodegradation capabilities of two bacterial strains, Rhodococcus erythropolis and Paenarthrobacter nitroguajacolicus, identifying P. nitroguajacolicus as a novel candidate for its ability to degrade low-density polyethylene (LDPE), a major contributor to plastic pollution. Both strains were isolated from plastic-contaminated environments and cultivated in laboratory conditions with LDPE as the sole carbon source. Viable cell count measurements revealed that P. nitroguajacolicus achieved a peak bacterial count of approximately 2 × 106 CFU/mL, with intermittent increases observed over the 45-day incubation period. In comparison, R. erythropolis exhibited a more stable trend, with a peak count of 5 × 105 CFU/mL. These findings highlight the superior growth potential of P. nitroguajacolicus on LDPE. ATP measurements indicated significant metabolic activity, with P. nitroguajacolicus showing higher vitality with an RLU value of 135 compared to R. erythropolis, which recorded an RLU of 96. This supports the assertion that Pn is metabolically more active in degrading LDPE. Additionally, structural and chemical changes in LDPE were confirmed using Scanning Electron Microscopy (SEM), Nuclear Magnetic Resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy. R. erythropolis demonstrated more pronounced surface degradation of LDPE, while P. nitroguajacolicus exhibited higher metabolic activity, emphasizing their complementary roles in biodegradation. This study highlights the potential of these bacteria in sustainable bioremediation strategies for mitigating plastic pollution, with P. nitroguajacolicus emerging as a novel and particularly promising candidate due to its degradative capacity for LDPE.

Geography-guided industrial-level upcycling of polyethylene terephthalate plastics through alkaline seawater-based processes

The escalating plastic crisis can be mitigated by upgrading waste polyethylene terephthalate (PET). Leveraging the geographical advantages of offshores with established chlor-alkali industries, abundant renewable energy, and extensive seawater, we here present a technically and economically viable strategy of harnessing natural seawater as a medium to transform PET plastics into high-value chemicals. We report a nickel-molybdenum catalyst incorporating frustrated Lewis pairs for the efficient breakage of C─C bond and the oxidation of ethylene glycol, which sustains a current of 6 amperes at 1.74 volts over 350 hours, with a projected revenue of approximately $304 United States dollar (USD) per ton of processed PET plastics. In a customized electrolyzer, we successfully convert 301.0 grams of waste PET into 227.1 grams of p-phthalic acid (95.5% yield), 1486.2 grams of potassium diformate (67.2% yield), and approximately 214.9 liters of green hydrogen. This study paves the way for scalable PET upcycling, contributing to a circular economy and mitigating the plastic pollution crisis.

Nano and Microplastics: Unveiling Their Profound Impact on Endocrine Health

Plastics are extensively used materials with a long environmental lifespan, posing significant risks to human health and the environment. Global plastic consumption has surged, with plastic waste expected to triple by 2060. The primary concern is the breakdown of plastics into nano and micro-sized particles, which can enter the body and have been detected in various organs and tissues.This review systematically examines the effects of micro and nanoplastics (MNPs) on the endocrine system using in vitro and in vivo experimental models. Following PRISMA guidelines, articles were sourced from databases like PubMed, Web of Science, and Scopus. After screening for relevance and removing duplicates and non-English articles, 103 articles focusing on the endocrine effects of MNPs were selected.MNPs can disrupt endocrine functions, altering reproductive hormones and gene expression patterns. In vivo exposure to MNPs increases inflammatory markers such as TNF-α, IL-6, IL-1β, and NF-κB, leading to apoptosis, inflammation, and oxidative stress. These disruptions impact the gonads, thyroid glands, and hormone secretion from the pituitary and hypothalamus. Most studies focus on terrestrial animals, with polystyrene being the most commonly used polymer.Future research should explore various plastic polymers, longer exposure durations, a broader range of concentrations, and human-level studies to better understand the toxicity of plastic particles. Reducing exposure to these pollutants requires legal changes, consumer behavior adjustments, and increased public awareness. Understanding the underlying processes can help propose methods to mitigate risks and protect human health.

Plastic Biodegradation by Sediment Microbial Populations under Denitrifying Conditions

Biodegradation is critical for eliminating plastic contaminants from environments, and understanding its mechanisms under in situ conditions is crucial. The plastic biodegradation process in sediments, a major reservoir of plastic contamination with reduced redox conditions, remains elusive. This study compared the plastisphere communities and metabolic potentials of typical polyethylene (PE) contaminants collected from the Pearl River Estuary to their counterparts in the surrounding sediments. The results revealed a distinct plastisphere community composition, with the consistent enrichment of a group of core plastisphere populations compared to those of the sediments. Functional genes related to both potential aerobic and anaerobic PE biodegradation were encoded by the core plastisphere populations. Microcosm incubations were performed to assess the PE biodegradation potentials under denitrifying conditions. The results demonstrated that the polyethylene (PE) mineralization efficiencies were comparable under aerobic and denitrifying conditions through incubations with 13C-PE. Development of functional groups on PE surfaces and the reduction in molecular weights further supported PE biodegradation under denitrifying conditions. The elevated laccase and lignin peroxidase activities implied their potential contribution to PE depolymerization under denitrifying conditions. Together, the sediment plastisphere microbiome holds the potential for plastic degradation under denitrifying conditions, which should be considered when assessing the fate of plastic contaminants.

Solar-driven Plastic Reforming With CO2 Conversion to Value-Added Chemicals Using Bifunctional Copper Hydroxide Catalyst

During coupling with carbon dioxide reduction reactions (CO₂RR), plastic reforming as an effective alternative anodic reaction to replace oxygen evolution reaction (OER), offers dual benefits of reducing energy consumption and producing valuable chemicals. However, balancing the energy requirements of polyethylene terephthalate (PET) oxidation with CO₂RR is challenging, as both half-reactions must operate under compatible conditions for high efficiency. Here, it is developed a bifunctional copper hydroxide catalyst capable of simultaneously converting both PET and CO₂ into valuable chemicals, which simplifies the system complexity. The copper hydroxide-derived catalyst achieves a formate FE of 89.5% produced on anode and an ethylene FE of 60.8% on cathode. It is discovered that CuOOH forms when Cu(OH)₂ is immersed in an EG electrolyte, enhancing EG adsorption and promoting its oxidation. After pre-reduction, the Cu(OH)₂-derived catalyst shows increased exposure of Cu(100) facets and enhanced C-C coupling for CO₂ reduction to ethylene. Driven by a silicon solar cell module, the product formation rates of 4.72 mmol/h/cm2 (formate) and 9.65 mmol/h/cm2 (ethylene) is achieved by the system at a current density of 302.7 mA/cm2. This work proposes a sustainable strategy utilizing a bifunctional catalyst for solar electrochemical upcycling of PET plastic, coupled with CO₂ reduction, to generate value-added fuels.

Imino-Pyrrole Zn(II) Complexes for the Rapid and Selective Chemical Recycling of Commodity Polymers

Three imino-pyrrole zinc complexes were prepared and applied to the rapid degradation of polylactic acid (PLA) and the depolymerization of bisphenol A polycarbonate (BPA-PC) and polyethylene terephthalate (PET). PLA alcoholysis proceeded rapidly at a range of conditions, including reflux in air. Remarkable activity was demonstrated for the solvent-free methanolysis of PLA at mild conditions with full conversion reached in 11 min at 80 °C. Various conditions were investigated including a range of PLA sources and, importantly, catalyst recycling was demonstrated. The methanolysis of BPA-PC and the glycolysis of PET were achieved, the latter giving full conversion after 1.5 h for all catalysts. The chemical recycling of mixed plastic feedstocks was investigated, including the selective and sequential degradation of a PLA/BPA-PC mixture with a single catalyst and solvent.

Plastic pellet spills and leakages during maritime transportation: a transdisciplinary approach to understand the complex causal pathways

Plastic pellets form the second largest source of microplastics in the marine environment and are found around the world. The origin of plastic pellet pollution is often linked to land-based industrial sites and transportation. However, recent spills resulting from accidents with ships have highlighted the significance of maritime shipping as a source of plastic pellet pollution. In addition, plastic pellets may be released from ships into the ocean as a result of operational leakages during maritime transportation. Although the need to address plastic pellet pollution from ships has been globally recognized, the scale and causal pathways behind this source have not been comprehensively documented and knowledge and data remain fragmented across resources and stakeholders. In order to advance the understanding of the causal pathways of plastic pellet spills and leakages during maritime transportation, this paper applied a transdisciplinary approach using mixed methods. These included expert and stakeholder consultations, systematic review of literature and industry data, and ultimately, the integration of all data in the form of cause-consequence diagrams. Causal pathways of plastic pellet spills and leakages during maritime transportation were found to be of four types of events, namely leaking containers, container damage, container lost overboard and loss of the vessel. Both the causes and consequences of these events were described, as such providing a basis for the identification of a comprehensive set of interventions. Mandatory requirements for the transport of plastic pellets should build upon a comprehensive set of interventions, addressing prevention as well as spill response.

Analysis of microplastics in the fjords of Tunu (East Greenland)

Microplastics (MPs) were surveyed in the fjords of Tunu (East Greenland), contributing important information to the scarce database on plastics in the Arctic. A total of 18 subsurface water samples were collected at eight stations along the northeast coast of Kalaallit Nunaat (Greenland) in August 2022. Sampling of the MPs was optimized and validated using traceable metal-doped model MPs. Recovery rates of the metal-doped MPs for validation of the sampling process using the Geesthacht Inert MP Fractionator were 78.7 ± 0.7 % (1 SD, n = 3) for a mixture of biofilm-coated Polyethylene terephthalate (PET) and Polylactic acid (PLA) particles. Samples were analyzed using laser direct infrared (LDIR) imaging. The reported MP number concentrations ranged from 1.0 ± 0.8 L-1 (1 SD, n = 3) to 12 ± 4 L-1 (n = 4) in the size range of 20-500 μm. The highest concentrations were observed at the mouth of the Kangertittivaq (Scoresby Sound), in the vicinity of the settlement Ittoqqortoormiit. PET was identified as the predominant polymer type, representing an average share of 96 %. PLA featured the second highest abundance, accounting for an average 1.6 % share. The analysis of conductivity-temperature-depth profiles revealed no significant evidence of MP input from glacial runoff. The results demonstrate the critical importance of collecting replicate samples, as short-term fluctuations in MP concentration and composition exceeded potential differences in their spatial distribution.

Bioinspired DNA Plastics with Brick-and-Mortar Structure: Enhanced Toughness, Recyclability, and Degradability

Bio-based plastics offer the advantage of biodegradability over traditional petroleum-based plastics, enabling natural reintegration into the environment and positioning them as a more sustainable alternative. DNA, as a natural biopolymer, exhibits excellent biocompatibility and degradability. However, the mechanical strength of currently biomass DNA-based materials is inferior to that of other bio-based and petroleum-based plastics. In this work, DNA plastics with a ″brick-and-mortar" structure were fabricated using DNA extracted from onions through bidirectional freezing, water vapor annealing, and compression densification. This biomimetic design significantly enhances the fracture toughness (∼1.5 MPa·m1/2) while possessing a high elastic modulus (∼560 MPa) of DNA plastic, making it superior or comparable to existing bio-based plastics and petroleum-based plastics, and thus positioning it as a potential structural material. Analysis of crack propagation behavior in DNA plastics reveals that their high toughness stems from a hierarchical ″brick-and-mortar″ structure operating across multiple length scales, facilitating a multiscale fracture process from macroscopic to molecular levels. Furthermore, these DNA plastics can be efficiently recycled in aqueous environments and fully biodegraded by enzymes, demonstrating strong environmental friendliness and significant potential for sustainable development.

Size-Dependent Toxicity of Polystyrene Nanoplastics to Tetrahymena thermophila: A Toxicokinetic-Toxicodynamic Assessment

Nanoplastic (NP) pollution poses a growing threat to aquatic ecosystems. Yet, accurate risk assessment based on their bioaccumulation and toxicity remains limited. Here, we synthesized polystyrene (PS) NPs with sizes of 30 nm (PS30), 100 nm (PS100), and 200 nm (PS200), labeled with aggregation-induced emission fluorogens. This labeling approach enabled precise tracking of NP uptake and elimination in the protozoan Tetrahymena thermophila, thereby circumventing issues of low fluorescence intensity and label leakage associated with conventional fluorescence labeling methods. Significant uptake and elimination of the differently sized PS NPs were observed with multiple endocytosis and exocytosis pathways involved. Then we evaluated the effects of PS NPs on the growth of T. thermophila and explored the toxicity mechanisms. Transcriptomic analysis revealed that PS NPs disrupted energy metabolism, lipid metabolism, and cellular uptake pathways, with PS30 even inducing genotoxicity. Using toxicokinetic-toxicodynamic modeling, we predicted median inhibitory concentrations (IC50) and no-effect concentrations (NEC) of the differently sized PS NPs across exposure durations. Under chronic exposure conditions, the NECs were 0.52, 2.1, and 3.9 mg L-1 for PS30, PS100, and PS200, respectively, which have been detected in aquatic environments. Overall, our study provides a robust framework to evaluate the risks of NPs based on their toxicokinetic-toxicodynamic processes.

Macroplastic surface characteristics change during wind abrasion

Mechanical abrasion is an important wind driven process which can degrade plastic litter on sandy beaches, desert environments and in agricultural settings. Wind-driven particle impacts can cause surface roughening and chemical changes and eventually complete fragmentation in high stress environments. Aeolian abrasion has been considered in the context of microplastics (< 5 mm) which can be easily mobilised by wind. However, macroplastic (> 5 mm) abrasion has primarily been confined to engineering studies using high air velocities (> 25 m s-1) and large abraders (> 6 mm) which generate greater impact forces than observed in the natural environment. Using laboratory abrasion experiments, we demonstrate that the surface microtextures and surface chemistry of three different types of plastic are substantially altered during the processes of aeolian abrasion at impact particle velocities of 0.6 m s-1. After ten days of continuous abrasion with four different erodents the macroplastic surfaces developed textures resulting from micro-cutting, denting, flaking, micro-pitting and surface flattening. The prevalence of each surface texture was dependent upon the angularity of the erodent and the type of plastic. In all cases, polymer surface chemical compositions became more complex due to embedding of shattered abrasive and the replacment of carbon with oxygen and silica.

Man-made polymers of natural compounds out weight microplastics in Australian seafood: Are we fixating on the wrong thing?

Pollution from synthetic microparticles such as microplastic (MPs) is of global concern. Semi-synthetic microparticles, also known as manufactured natural polymers (MNPs), have received much less scientific attention, despite their morphological similarity to MPs, comparable chemical additives, and the shared potential to act as vector for chemical substances and microorganisms. This study assessed MP and MNP levels in five popular seafood species: sand whiting (Sillago cillata), squids (Loligo spp.), eastern king prawns (Melicertus plebejus), blue swimmer crabs (Portunus armatus), and flatheads (family Platycephalidae) sold fresh in local fish markets from the Gold Coast, Australia. Samples from three tissue types (gill, gut, and muscle) were digested with 10 % KOH and filtered through 5-micron stainless steel filter meshes. Visual microscopic screening was carried out for isolated microparticles, and size, shape, and colour were recorded; then, isolated suspected microparticles were analysed by μ-FTIR to identify the polymer type. Our results show that 88.6 % of seafood available in local fish markets on the Gold Coast was contaminated with at least one particle of MP or MNP. Pelagic species contained a higher particle concentration (0.630 ± 0.064 particles/g) compared to demersal species (0.130 ± 0.019 particles/g. Non-edible tissues exposed to the external environment (gill and gut) contained significantly higher concentrations (0.545 ± 0.046 particles/g) of microparticles compared to edible tissue (muscle) (0.203 ± 0.025 particles/g). There was 1.1-3.2 time more MNPs than MPs in all tissue samples except in prawn muscle and flathead gill tissues, indicating that MNPs may pose a greater threat than previously recognised.

Characterization of Inorganic Additives in and Photochemically Liberated from Consumer Plastics: Implications for Global and Local Biogeochemical Cycles

The composition and environmental impacts of inorganic additives in consumer plastics have received little attention within the plastic pollution discipline relative to organic additives. In this work, X-ray florescence spectroscopy, loss-on-ignition, and inductively coupled plasma mass spectrometry were used to qualitatively and quantitatively characterize inorganic additives from up to 80 consumer plastic items. On average, consumer plastic goods contained ∼8% inorganic additives by mass. Concentrations of each element often varied by orders of magnitude. The most common elements detected were from the alkali metal, alkaline earth metal, and first-row transition metal groups, with Ca, Ti, and Al being most abundant. The diversity and abundance of inorganic additives was notably higher in consumer-grade plastics than in standard plastics routinely used to assess the fate and impacts of plastic pollution. Sunlight exposure readily liberated most elements from consumer plastics, typically in the <10 and <1 μm fractions. However, the relative percent of photochemical liberation varied considerably across element and plastic articles, suggesting that formulation is a key control of their liberation from consumer plastics. Compared to average upper continental crust concentrations, Sb and Zn were most enriched, with median enrichment factors of 2 and 1 orders of magnitude, respectfully. Mass balance calculations indicate that plastic pollution may represent a substantial proportion of natural riverine elemental fluxes, particularly for Sb and Zn, which could reach ∼13% and ∼4% of the global natural riverine fluxes by 2060, respectively. Localized impacts in many small, highly polluted rivers could be even larger. However, such impacts are highly dependent on the riverine plastic loading rate to the ocean. Overall, these findings highlight the need for increased consideration of inorganic additives when assessing the fate and impacts of consumer plastics leaking into the environment.

On-demand, readily degradable Poly-2,3-dihydrofuran enabled by anion-binding catalytic copolymerization

Copolymerization with cleavable comonomers is a versatile approach to generate vinyl polymer with viable end-of-life options such as biodegradability. Nevertheless, such a strategy is ineffective in producing readily degradable 2, 3-dihydrofuran (DHF) copolymer with high-molecular-weight (>200 kDa). The latter is a strong and biorenewable thermoplastic that eluded efficient cationic copolymerization synthesis. Here, we show that an anion-binding catalyst seleno-cyclodiphosph(V)azanes enable the efficient cationic copolymerization with cyclic acetals by reversibly activating both different dormant species to achieve both high living chain-end retention and high-molecular-weight. This method leads to incorporating low density of individual in-chain acetal sequences in PDHF chains with high-molecular-weight (up to 314 kDa), imparting on-demand hydrolytic degradability while without sacrificing the thermomechanical, optical, and barrier properties of the native material. The proposed approach can be easily adapted to existing cationic polymerization to synthesize readily degradable polymers with tailored properties while addressing environmental sustainability requirements.

Hydrolytic Degradation of Key Plastic Pollutant Model Systems by a Discrete Metal-Oxo Cluster: A Combined Theoretical and Experimental Study

Degradation of plastic materials represents one of the major challenges faced by the modern world. In this study, computational and experimental techniques have been employed to investigate the hydrolysis of most commonly used plastic materials poly(ether urethane) (PEU) and polyethylene terephthalate (PET) and their commercially available models ethyl N-phenylcarbamate (ENP) and ethylene glycol dibenzoate (EGD), respectively, by a discrete metal-oxo cluster, Zr-substituted Keggin-type polyoxometalate, (Et2NH2)8[Zr(μ-O)(H2O)(PW11O39)] (ZrK), in which the Zr(IV) catalytic site is stabilized by coordination to a robust metal-oxo core. The all-atom molecular dynamics simulations predicted that all substrates interact with ZrK through water-mediated interactions. The quantum mechanics/molecular mechanics (QM/MM) calculations showed that the lengths of scissile ester and amide bonds of PEU/ENP and the ester bond of PET/EGD are quite similar, and the hydrolysis of PEU and ENP and PET and EGD occurs with similar energetics. According to the most plausible mechanisms, the cleavage of the ester and amide bonds of PEU/ENP takes place with a barrier of 16.5/16.6 and 19.0/20.4 kcal/mol, respectively. However, the scissile ester bond of PET/EGD is hydrolyzed with a barrier of 16.7/16.5 kcal/mol. This computed difference in the rate-limiting barrier of 3.9 kcal/mol between the amide bond of ENP and the ester bond of EGD is supported by the experimentally observed sluggish hydrolysis of ENP in comparison to EGD. While both ENP and EGD were successfully hydrolyzed by ZrK in DMSO solvent at 100 °C, EGD hydrolysis has proven to be much more efficient, with 99% yield obtained within 18 h compared to 48% of ENP hydrolysis observed after 162 h. The combined theoretical and experimental results presented here contribute to the development of potent and robust all-inorganic cluster-based catalysts for the degradation of PEU and PET and suggest that ENP and EGD can be used as excellent model substrates in this endeavor.

Atomic Cu-O-Zr Sites for Highly Selective Production of p-xylene from Tandem Upcycling of PET and CO2

Exploring an efficient catalytic system for tandem upcycling of CO2 and polyethylene terephthalate (PET) is highly desirable for achieving efficient resource utilization of wastes. However, the high activation energy for C═O bonds (in both PET and CO2) and the difficulty in regulating the reaction pathways restricted PET recovery efficiency. Here, we demonstrated the rational design of a single-atom Cu catalyst for precisely catalyzing the hydrogenation of CO2 to methanol and tandem PET upcycling to ethylene glycol (EG) and p-xylene (PX). In the Cu/UiO-66-NH2-A catalyst, Cu atoms are selectively anchored to the Zr-oxo nodes of UiO-66-NH2 to form Cu-O-Zr sites. The Cu-O-Zr sites can effectively activate both CO2 and H2 by reducing the activation energy and accelerate the transformation of PET to dimethyl terephthalate (DMT), which is further hydro-deoxygenated to yield PX. As a result, 20.4% CO2 conversion was obtained within 36 h, with 89.5% and 92.1% yields of PX and EG, respectively. Rapid and precise hydrogen spillover from Cu atoms to adsorbed reactants/intermediates at the Cu-O-Zr sites also drives the reaction process.

Impacts of polystyrene nanoplastics on zebrafish gut microbiota and mechanistic insights

Aquatic environments are frequently contaminated with nanoplastics (NPs) ranging from 1-100 nm generated by plastic aging, but their bio-enrichment and toxicological impacts remain poorly understood. This study investigates how chronic exposure to carboxylated polystyrene nanoplastics (PNPs) alters gut microbiota composition and function in zebrafish (Danio rerio). Adult zebrafish were exposed to 50 nm PNPs at concentrations of 0.1, 1.0, and 10 mg/L for 14 and 28 days, followed by gut microbiota analysis using 16S rRNA gene sequencing. PNP exposure altered gut microbiota composition, including an increase in Proteobacteria abundance and a decrease in Firmicutes, Bacteroidetes, and the inflammation-related genus Alistipes. Beneficial probiotics such as Faecalibacterium, Streptococcus, Bifidobacterium, and Lachnospira were diminished, while pathogenic bacteria proliferated. TEM imaging revealed the internalization of PNP particles within intestinal tissues resulted in vacuolation, suggesting potential epithelial damage. Co-occurrence network patterns of gut microbiota greatly decreased during treatment with NPs. The neutral community model showed that among PNP treatments, 0.1 mg/L led to a less predictable (stochastic assembly process). PNP exposure led to increased predicted microbial functions (via PICRUSt2) related to xenobiotic metabolism, infection pathways, and lipopolysaccharide (LPS) production, while RNA transport and N-glycan biosynthesis were decreased. However, pathways related to microbial antioxidants exhibited significant variation across different PNP levels. These results provide critical insights into the toxicological impacts of chronic PNP exposure on fish gut health, highlighting the potential risks to aquatic ecosystems and human health.

Plastic pollution in mangrove ecosystems: A global meta-analysis

Mangrove ecosystems play a crucial role in blue carbon sequestration, coastal flood protection, and biodiversity conservation, while also serving as nursery habitats for threatened and economically important species. Due to their complex root structures, mangroves act as natural plastic traps, making them vulnerable to marine plastic contamination. In this study, we conducted a meta-analysis synthesising available global data on macroplastic and microplastic pollution in mangrove ecosystems, assessing their prevalence and the environmental partitioning of plastics both within and outside Marine Protected Areas (MPAs). We reviewed 44 primary studies and conducted statistical analyses to compare plastic abundance in the sediment, water, and biota. Our results show that mangrove ecosystems experience significant plastic pollution. Macroplastic abundance within the studied mangroves varied by five orders of magnitude, averaging 23.73 ± 8.80 items m-2, comparable to the highest levels recorded on beaches and underscoring the plastic-trapping capacity of mangroves. Mangroves globally had a mean contamination of 1122.98 ± 150.17 microplastics kg-1 in sediment and 16.00 ± 11.04 microplastics L-1 in seawater, both approximately double estimated safe limits. Our analyses found a 45.5 % reduction in microplastic within mangrove sediments and an 83.3 % reduction in macroplastic contamination in protected mangrove ecosystems. However, seawater microplastic levels were higher within MPAs, particularly near urbanized areas. These findings emphasize the need for integrated mitigation strategies that combine MPAs with targeted plastic waste reduction measures. Our analyses also highlight that the ecological impacts of this plastic accumulation within mangrove ecosystems remains a key knowledge gap.

High-performance recyclable polymers enabled by stereo- and sequence-controlled polymerization

Monomer design strategy has become a powerful tool to access chemically recyclable polymers with desired and diverse properties. The presence of two or multiple stereogenic centres in one monomer offers a new dimension to fine-tune the polymer performance. However, it is still a formidable challenge in synthetic polymer chemistry to achieve precise stereocontrol and sequence control over the polymer microstructure. Here we report a stereo- and sequence-controlled polymerization of 5H-1,4-benzodioxepin-3(2H)-one-based monomers with two stereogenic centres (M) to furnish a series of isoenriched AB diblock polymers P(cis-M)-b-P(trans-M) and ABA triblock polymers P(trans-M)-b-P(cis-M)-b-P(trans-M). Notably, P(cis-M2)900-b-P(trans-M2)38 delivered impressive toughness and ductility, comparable to the commodity plastic isotactic polypropylene; the ABA triblock P(trans-M2)26-b-P(cis-M2)900-b-P(trans-M2)26 appeared to be softer and resembled low-density polyethylene. These various materials could fully convert to the monomer M. The establishment of stereo- and sequence-controlled polymerization not only provides an effective and robust strategy to tailor polymer properties on the molecular level, but also delivers various chemically recyclable materials that can be converted back to monomers.

Photoaging Promotes Toxic Micro/Nanoplastics Release from PLA/PBAT Biodegradable Plastic in Gastrointestinal Condition

The release of micro/nanoplastics (MNPs) from biodegradable plastics in gastrointestinal environments due to photoaging, along with their associated mechanisms and potential cytotoxicity, is largely unknown. Here, we show that poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) films undergo ultraviolet photoaging, resulting in increased surface roughness and a higher quantity of MNPs on the surface. This aging process involves the generation of carbon- and oxygen-centered free radicals, chain scission, and the formation of oxidation products with hydroxyl and carbonyl groups. These MNPs can be released under water shear force, significantly increasing the normalized mass loss of aged films to approximately 0.128 mg/cm2 (18 times higher than that of unaged films in water). In the gastrointestinal environment, the normalized mass loss further increases to about 0.196 mg/cm2 (28 times higher), likely due to potential enzymatic digestion and ion-swelling effects. These MNPs, primarily composed of PLA, are smaller and carry more negative charges under gastrointestinal conditions. In the THP-1 cell model, these MNPs affect cell viability in a dose-dependent manner. MNPs obtained through ultrafiltration, compared to those collected via centrifugation, display a broader size distribution and induce more pronounced toxicity in THP-1 cells, with an EC50 of 243 mg/L. Preliminary comparative analysis indicates that PLA/PBAT-derived MNPs present toxicity risks comparable to, or greater than, those of conventional plastic MNPs. These findings underscore the potential hazards associated with biodegradable plastics.

Bridging the knowledge gap: From poly(butylene adipate-co-terephthalatebutylene) degradation to CO2-generating mineralization under the synergistic effect of bacteria and fungi

Poly(butylene adipate-co-terephthalate) (PBAT) is a promising polymer with excellent mechanical properties and biodegradability. However, knowledge gaps between its degradation and mineralization processes in soil hampers its environmental impact and application potential. In this study, we elucidated the degradation process of PBAT, starting with the degradation of high-molecular-weight polymers into 30 intermediates, before ultimately mineralized into CO2. Bacteria and fungi drove the degradation and mineralization of these intermediates. We discovered that PBAT was synergistically degraded by combinations of 27 bacterial and fungal biomarkers rather than by single biomarkers dominated by Bacteroidota, Acidobacteriota, and Ascomycota. These combinations of related functional genes perform various functions at every stage of PBAT degradation, including breaking down molecular structures, degrading intermediates, and mineralization. Bacterial biomarkers showed greater diversity than fungal biomarkers in degrading PBAT. Our findings provide useful insights into the degradation of PBAT in soil and a foundation for systematically evaluating and controlling the environmental behavior and safety of PBAT in soil.

Microscopic anthropogenic waste ingestion by small terrestrial European passerines: evidence from finch and tit families

Microscopic anthropogenic waste (MAW) has become a major environmental concern worldwide. Our study aimed to assess the accumulation of MAW in the gastrointestinal tracts of nine common European passerine species from finch (Fringillidae) and tit (Paridae) families, and evaluate their suitability for environmental monitoring. We searched for MAW in the birds' stomachs and intestines and identified suspected particles using Raman microspectroscopy. In total, we found 57 MAW particles in 31 out of 149 analyzed individuals, 7 of which were microplastics (polyethylene, polyethylene terephthalate, polystyrene), 1 was identified as carbon nanotube, while 49 were cellulosic-based (cotton, cellulose, rayon, viscose). The generalized linear mixed models identified bird family and time in season as significant predictors of MAW ingestion. Finches ingested more MAW than tits, and higher ingestion rates were observed during the non-breeding period. Other predictors, including bird sex, age, gastrointestinal tract section, and site, showed varying but non-significant effects. As predicted, the studied species exhibited a lower ingestion rate of MAW compared to terrestrial birds studied so far, possibly due to their diet and feeding behavior. Given that these species are prey for many avian and non-avian predators, they may contribute to the transfer of MAW to higher trophic levels.

Plastic and rubber polymers in urban PM10 by pyrolysis-gas chromatography-mass spectrometry

Microplastics, including tyre and road wear particles, have been detected in every environmental compartment in both urban and remote areas. However, their contribution to atmospheric particulate matter is still sparsely explored. These airborne micro- and nanosized particles are continuously inhaled and pose risks to the environment and public health. The objectives of this study were to develop and validate a thermoanalytical method for the quantification of microplastics in urban particulate matter. Aerosol particles smaller than 10 µm in aerodynamic diameter (PM10) were sampled at the kerbside in Helsinki, Finland, during spring 2024. The samples were pretreated by homogenization and thermal desorption prior to chemical analysis by micro-furnace pyrolysis-gas chromatography-mass spectrometry. The developed method was validated in terms of selectivity, limits of quantification, linear range, trueness, precision, and measurement uncertainty. Instrument quantification levels were 8-270 ng. Expanded measurement uncertainties were 25-30% and 50-70% for the studied tyre wear rubbers and thermoplastics, respectively. Polyethylene, polyethylene terephthalate, polypropylene, polystyrene, and tyre and road wear particles were detected in urban PM10 samples, and their sum accounts for 1-3% of total PM10. These results represent the level of airborne microplastic particles to which people can be exposed in urban environments.

The Analysis of Polylactic Acid Oligomers and Their Fate in Laboratory and Agricultural Soil

Polylactic acid (PLA) is the most widely consumed biodegradable plastic worldwide. Though PLA products have the advantages of easy degradation and a small carbon footprint, poly(lactic acid) oligomers (OLAs) released from PLA have been found to exhibit toxicity. Accurate quantification of the presence of the OLAs in soil is crucial for understanding their occurrence and environmental fate. In this study, we synthesized sequence-defined OLA standards and deuterated OLAs (d-OLAs) and developed a broad-spectrum extraction method with water-saturated ethyl acetate and 0.1% formic acid, achieving sensitive and precise quantification of the OLAs across various soil environments. The simulated experiments showed that PLA-based products released amounts of OLAs, reaching their peak within 24 h, followed by degradation, with the OLAs remaining detectable in the soil for up to 168 h. Meanwhile, the OLA with a degree of polymerization (DP) of 2 exhibited the highest concentration, while higher-DP OLAs demonstrated greater stability in soil compared to others. In the field samples, OLAs were detected in soil over the long term beneath PLA-based biodegradable mulch films with residual concentrations reaching up to 16.10 ± 0.37 ng/g. This study bridges foundational analytical methods and addresses data gaps for further investigations into the environmental fates of the OLAs and PLA.

Aliphatic Polyester Recognition and Reactivity at the Active Cleft of a Fungal Cutinase

Protein engineering of cutinases is a promising strategy for the biocatalytic degradation of non-natural polyesters. We report a mechanistic study addressing the hydrolysis of the aliphatic polyester poly(butylene succinate, or PBS) by the fungal Apergillus oryzae cutinase enzyme. Through atomistic molecular dynamics simulations and advanced alchemical transformations, we reveal how three units of a model PBS substrate fit the active site cleft of the enzyme, interacting with hydrophobic side chains. The substrate ester moiety approaches the Asp-His-Ser catalytic triad, displaying catalytically competent conformations. Acylation and deacylation hydrolytic reactions were modeled according to a canonical esterase mechanism using umbrella sampling simulations at the quantum mechanical/molecular mechanical DFT(B3LYP)/6-31G**/AMBERff level. The free energy profiles of both steps show a high-energy tetrahedral intermediate resulting from the nucleophilic attack on the ester's carboxylic carbon. The free energy barrier of the acylation step is higher (20.2 ± 0.6 kcal mol-1) than that of the deacylation step (13.6 ± 0.6 kcal mol-1). This is likely due to the interaction of the ester's carboxylic oxygen with the oxyanion hole in the reactive conformation of the deacylation step. In contrast, these interactions form as the reaction proceeds during the acylation step. The formation of an additional hydrogen bond interaction with the side chain of Ser48 is crucial to stabilizing the developing charge at the carboxylic oxygen, thus lowering the activation free energy barrier. These mechanistic insights will inform the design of enzyme variants with improved activity for plastic degradation.

Effects of defined organic layers on the fluorescence lifetime of plastic materials

Plastics have become an integral part of modern life, and linked to that fact, the demand for and global production of plastics are still increasing. However, the environmental pollution caused by plastics has reached unprecedented levels. The accumulation of small plastic fragments-microplastics and nanoplastics-potentially threatens organisms, ecosystems, and human health. Researchers commonly employ non-destructive analytical methods to assess the presence and characteristics of microplastic particles in environmental samples. However, these techniques require extensive sample preparation, which represents a significant limitation and hinders a direct on-site analysis. In this context, previous investigations showed the potential of fluorescence lifetime imaging microscopy (FLIM) for fast and reliable identification of microplastics in an environmental matrix. However, since microplastics receive an environmental coating after entering nature, a challenge arises from organic contamination on the surface of microplastic particles. How this influences the fluorescence signal and the possibility of microplastic detection are unknown. To address this research gap, we exposed acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate (PET) plastic samples to peptides, proteins, bacteria, and a filamentous fungus to induce organic contamination and mimic environmental conditions. We analyzed the fluorescence spectra and lifetimes of the samples using fluorescence spectroscopy and frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM), respectively. Our results demonstrate that reliably identifying and differentiating ABS and PET was possible via FD-FLIM, even in the presence of these biological contaminations. These findings highlight the potential of this technique as a valuable tool for environmental monitoring and plastic characterization, offering a rapid and efficient alternative to currently used analytical methods.

Quantifying the Effect of Dietary Microplastics on the Potential for Biological Uptake of Environmental Contaminants and Polymer Additives

The pervasive presence of microplastic in food raises the question of how this presence influences the uptake of organic contaminants from the gastrointestinal tract. Depending on the relative contamination of diet and microplastics, the latter can act either as a vector of contaminants facilitating biological uptake or as a contaminant sink whose sorptive capacity does not diminish during digestion. A comprehensive understanding of these effects ultimately requires the quantification of the effect of microplastics on the thermodynamic driving force responsible for diffusion from the gut lumen to the tissues of an organism. Using silicone-based equilibrium sampling, we quantified the effect of polyvinyl chloride (PVC) microplastics on the fugacity of polychlorinated biphenyls (PCBs) and two polymer additives in dietary and fecal samples of a zoo-housed polar bear. Although PVC microplastics at concentrations well above current observations reduced the fugacities of spiked isotopically labeled PCBs in the polar bear diet and feces slightly, but significantly, leaching from these microplastics greatly elevated fugacities of the additives UV-328 and octabenzone in these samples. The impact of microplastics in the diet on the biological uptake of environmental hydrophobic organic contaminants is likely to be negligible. Microplastics have the potential to be effective vectors for the dietary uptake of polymer additives.

Diluted alkaline pretreatment in hexafluoroisopropanol facilitates chemoenzymatic depolymerization of polyethylene terephthalate

Enzymatic PET degradation presents a sustainable and eco-friendly solution for recycling and upgrading PET materials. While various PET-degrading enzymes have proven effective in converting low-crystallinity PET into monomers, their efficiency decreases significantly for high-crystallinity PET. Given that most commercially available PET products are highly crystalline and have a limited specific surface area, conventional methods typically resort to heat treatment and ball milling to achieve decrystallization and micronization before enzymatic hydrolysis. However, these pretreatments often compromise environmental benefits due to their high energy consumption and dust pollution, and are difficult to scale up. In this study, we developed a chemoenzymatic strategy that efficiently depolymerizes waste PET materials into monomers in just 4 h. This process involves an alkaline treatment with diluted NaOH in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), followed by enzymatic hydrolysis of the PET nanosuspensions generated from solvent exchange. The alkaline treatment partially breaks down the PET molecular chains and mitigates recrystallization during the precipitation process. Importantly, the complete hydrolysis of PET is attributed to reduced crystallinity rather than particle size. Notably, this method eliminates the need for PET micronization and minimizes the usage of NaOH. The effectiveness of this method was demonstrated through the hydrolysis of various commercially available PET products, showcasing its potential to advance enzymatic degradation processes for PET recycling.

Comparison of Microplastics between Lung Tissues and Intestinal Contents in Finless Porpoises (Neophocaena asiaeorientalis)

Microplastics are ubiquitous environmental pollutants in terrestrial, marine, and atmospheric ecosystems. Plastic inputs into the atmosphere occur through weathering or abrasion, dispersing microplastics globally, which can enter the animals' respiratory systems through inhalation. We analyzed the lung tissues for the first time and the intestinal contents of 11 dead finless porpoises (Neophocaena asiaeorientalis) to assess the intake of microplastics from prey and atmospheric sources. The lung tissues and intestinal contents contained average concentrations of 0.14 ± 0.11 MPs/g and 0.35 ± 0.36 MPs/g, respectively. Microplastics found in the lung tissues and intestinal contents were similar in physical characteristics (e.g., fragment shape, transparent to white color, and size <100 μm). On the other hand, they differed in the polymer types, with a higher proportion of epoxy-type microplastics in the lungs. Epoxy is a highly hazardous polymer according to the polymer hazard index, and in the present study, the lung tissues had a higher plastic hazard index than the intestinal contents. Hence, the respiratory system is more vulnerable to microplastic pollution from atmospheric sources than the digestive system is from water and food intake. These findings underscore the growing threat of airborne microplastics to lung-breathing animals including marine mammals.

Persistence and Recovery of Polystyrene and Polymethyl Methacrylate Microplastic Toxicity on Diatoms

The increasing pollution of polystyrene (PS) and polymethyl methacrylate (PMMA) microplastics (MPs) has become a global marine environmental problem. Diatoms contribute nearly 40% of marine primary productivity and shape the nitrogen cycle in the oceans. However, the persistence of the phytotoxicity of MPs on diatoms, especially nitrogen assimilation, remains largely unknown. To examine the persistence of PS and PMMA toxicity in diatoms, two subexperiments (a 96 h exposure followed by a recovery phase) were conducted on Thalassiosira pseudonana at concentrations ranging from 0.001 to 1 mg/L. The results showed that PS and PMMA inhibited algal growth by 3.76-6.49% and 4.44-8.37%; increased oxidative stress by 10.06-30.51% and 30.46-38.12%; and caused ultrastructural damage by 14.24-25.56% and 12.28-20%, respectively, consistent with the downregulation of glyoxylate, dicarboxylate metabolism, and glutathione metabolism. At the recovery stage, the algal density induced by PS was significantly recoverable at 0.001 and 0.01 mg/L, consistent with the enhanced carbohydrate metabolisms. After recovery, the cell permeability and reactive oxygen species (ROS) levels induced by PS and PMMA were significantly decreased at 1 mg/L, respectively, which was closely related to the downregulation of glycine, serine, and threonine metabolism and the upregulation of pantothenate and coenzyme A biosynthesis. Moreover, the inhibition of nitrogen assimilation enzymic activities induced by PS and PMMA was significantly recovered at 1 mg/L despite the downregulation of nitrogen metabolism. This study highlights the phenomena and mechanisms of phytotoxicity and recovery, and provides new insights for comprehensive understanding and evaluation of environmental risks of MPs.

Accumulation of benzotriazole UV-stabilizers in relation to ingested plastics and associated health metrics in Larus gulls feeding at a landfill in Atlantic Canada

Benzotriazole UV-Stabilizers (BZT-UVs), compounds added to plastics to reduce ultraviolet degradation, are considered contaminants of emerging concern given their environmental persistence and documented toxicity in humans and animals. UV328 is a BZT-UV that has been recently listed to Annex A of the Stockholm Convention; therefore, understanding species exposure is critical information to fulfill international and domestic regulatory obligations. We evaluated hepatic accumulation of 12 plastic additives (including nine BZT-UVs) in Larus gulls in Atlantic Canada. BZT-UV accumulation was assessed in relation to ingested plastics, hepatic heavy metal accumulation, and body condition. Ninety-six percent of gulls had at least one BZT-UV at detectable hepatic concentrations. The most frequently detected BZT-UVs were UVP (91.4 %) and UV328 (76 %), suggesting ubiquitous exposure across individuals. We demonstrated interspecific differences in the relationship between ingested plastics and accumulated contaminants, with a positive relationship detected between ingested plastics and both UVP and UV328 in American herring gulls (Larus argentatus smithsonianus), and a positive relationship between hepatic UV328 and Pb concentrations detected in great black-backed gulls (Larus marinus). We provide evidence that Larus gulls feeding at a coastal landfill are highly exposed to BZT-UVs, and that the relationship between ingested plastics and plastic-associated contaminants varies across sympatric species.

Chemical Food Safety in Europe Under the Spotlight: Principles, Regulatory Framework and Roadmap for Future Directions

Chemical food safety is a fundamental pillar of public health, regulatory governance, and economic stability, with far-reaching implications for human, animal, and environmental well-being. In the matter of chemicals in the food chain, the European Union (EU) has established one of the most sophisticated and robust regulatory frameworks to ensure food safety and balance consumer protection with scientific advancements and industry needs. This review provides a holistic analysis of the EU chemical food safety scenario, examining its regulatory framework, key risk assessment methodologies, and the roles of critical institutions involved in monitoring, enforcement, and policymaking. The new and evolving challenges of chemical food safety, including transparency, cumulative risk assessment, and emerging contaminants, were discussed. Special attention is given to major classes of chemical substances in food, their regulatory oversight, and the scientific principles guiding their assessment, as well as to the role of key actors, including regulatory agencies, official laboratories, and competent authorities. This work offers an updated and integrated analysis of chemical food safety in the EU, uniquely combining regulatory, scientific, and enforcement perspectives and providing a structured roadmap for future directions.

Atmospheric emissions of microplastics entrained with dust from potential source regions

Atmospheric microplastics play an important role in the microplastic cycle. However, their behaviors in high-altitude remote areas were still poorly constrained. Based on one year of samples from the northeast Tibetan Plateau, we investigated the status of atmospheric microplastics and their relationships with dust. The results indicated that number-based concentrations of atmospheric microplastics were 4.07 ± 2.37 items m-3 with the maximum in spring, while mass-based concentrations were 0.126 ± 0.152 μg m-3 with the maximum in winter. Atmospheric microplastics < 50 μm accounted for 92.9 %, with 95.4 % being fragments, emphasizing the pervasive occurrence of small-sized fragmented microplastics in the northeast Tibetan Plateau. Analysis of Lagrangian particle dispersion model combined with potential source contributions revealed that dust emission in potential source regions significantly impacted atmospheric microplastic concentrations. The threshold shear velocity of microplastics and dust exhibited similar values, supporting their co-emissions from potential source regions. Once microplastics are entrained into the airflow, the lower updraft wind speed required for microplastic suspension facilitates long-range atmospheric transport. This study enhanced our insights into the atmospheric microplastic sources and supported future mitigation strategies for microplastic exposure in the remote ecosystem.

The vertical migration of a pesticide mixture in sandy soil is strongly driven by their sorption behavior and can be altered by Polyethylene Microplastics

With the revelation of microplastics in soil, their interaction with organic chemicals has received increasing attention due to their hydrophobic surfaces, substantial sorption capacity, and large specific surface area. However, existing studies focus mainly on individual pollutants rather than their coexistence in environmental mixtures. Our study aimed to extend focus from single compounds to complex contamination by 20 pesticides which we applied to reference sandy soil. Stainless steel columns were filled with soil with or without the addition of 1 % w/w polyethylene (PE) microplastics cryo-milled to irregular shape and sieved to a size of 200-600 µm. The columns were continuously rinsed with ten pore volumes (PVs) of the pesticide-contaminated solution. The leachates were collected and measured every 0.2 PV using LC-MSMS to derive breakthrough curves (BTCs). The results showed that migration rates decreased with increasing hydrophobicity (as DOW and KOC), while the leaching order of pesticides was unaffected by the microplastics. However, PE microplastics promoted the vertical migration of five slowly leaching pesticides despite their high sorption affinity to the soil. Overall, our results indicate that the sorption capacity of soils contaminated with microplastics for such chemicals can be decreased, promoting faster leaching and enhancing the potential of groundwater contamination. This study extends previous research from a single pesticide to various co-presences, while connecting the physicochemical properties of pesticides, microplastic contamination, and vertical migration patterns.

One-Pot Depolymerization of Mixed Plastics Using a Dual Enzyme System

As global plastic consumption and littering escalate, innovative approaches to sustainable waste management are crucial. Enzymatic depolymerization has emerged as a promising recycling method for polyesters via monomer recovery under mild conditions. However, current research mainly focuses on using a single plastic feedstock, which can only be derived from complex and costly plastic waste sorting. This study investigated the enzymatic depolymerization of mixed plastics using a dual-enzyme system in a one-pot approach. Employing the polyester hydrolase PES-H1 FY and the (poly)urethanase UMG-SP-2, mixed or blended polymers consisting of polyethylene terephthalate (PET), polybutylene adipate-co-terephthalate (PBAT), and thermoplastic polyester-polyurethane (TPU) were depolymerized into their monomers. Chromatographic quantification revealed a total yield of monomeric products of up to 39.8±4.4 % after 96 h reactions, which was consistent with the weight loss measurements of 40.9±2.5 %. In addition, a modified dissolution-precipitation method was shown to easily blend the three different polymers while improving their degradability. Our findings suggest that using mixed enzymes is a viable method for recycling mixed or blended waste plastics without polymer sorting. Individual monomers can be separated and purified to produce virgin polymers, while their mixture in the hydrolysate can easily serve as feedstock for microbial upcycling into value-added products.

Toxicological effects and mechanisms of renal injury induced by inhalation exposure to airborne nanoplastics

Micro-nanoplastics (MNPs) are ubiquitously present in various natural habitats, and the kidney plays a critical role in eliminating metabolic waste from the body. Therefore, nephrotoxicity studies of MNPs are necessary. Consequently, we conducted a study utilizing a mouse model that underwent autonomous inhalation of polystyrene nanoplastics (PS-NPs) to investigate the impact of airborne nanoplastics (NPs) on kidney. The results demonstrated that airborne NPs could accumulate within the kidney subsequent to pulmonary entry. Transcriptome analysis showed that exposure to airborne NPs persistently interfered with important signaling pathways including oxidative stress, inflammation, and coagulation, which activated the NR4A1/CASP3 and TF/F12 signaling pathways. In vitro studies have shown that NPs were internalized by human kidney proximal tubular epithelial (HK-2) cells, leading to a range of pathological responses, and ultimately affecting cell fate. Furthermore, we pioneered the exposure of NPs to human kidney organoids. Our findings revealed a heightened sensitivity in kidney organoids towards NPs as compared to immortalized cell lines. This suggested that exposure to NPs could potentially inflict a more substantial toxic effect on the development of embryonic kidneys. In conclusion, this study has revealed the deleterious effects of exposure to airborne NPs on the mouse kidney.