Polyurethane (PU) synthetic leathers possess an intricate plastic composition, including polyester (PET) base fabrics and upper PU resin, but the release of fragments from the complexes is unclear. ...Therefore, we investigated the photodegradation trends of PET base fabrics with PU coating (PET-U) as a representative of composite plastics. Attention was paid to the comparison of the photoaging process of PET-U with that of pure PET base fabric (PET-P). To reveal the potential for chain scission, physical and chemical changes (e.g., surface morphology, molecular weight, and crystallinity) of the two fabrics were explored. The generation of microplastic fibers (MPFs) and microplastic particles (MPPs) was distinguished. Compared with PET-P, PET-U showed a similar but delayed trend in various characteristics and debris release rate as the photoaging time prolonged. Even so, after 360 h of illumination, the generated number of MPs (including MPFs and MPPs) rose considerably to 9.32 × 107 MPs/g, and the amount of released nanoplastics (NPs) increased to 2.70 × 1011 NPs/g from PET-U. The suppression of MP formation from PET-U was potentially directed by the physical shielding of the upper PU layer and the dropped MPs, which resisted the photochemical radical effect. The components of dissolved organic matter derived from plastics (P-DOM) were separated by molecular weight using a size-exclusion chromatography–diode array detector–organic carbon detector/organic nitrogen detector (SEC-DAD-OCD/OND), and the results showed that a larger amount of carbon- and nitrogen-containing chemical substances were generated in PET-U, accompanied by more aromatic and fluorescent compounds. The results provided theoretical bases and insights for future research on the risks of plastic debris from PU synthetic leathers on aquatic organisms and indicated feasible directions for exploring combined pollution studies of plastics.
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IJS, KILJ, NUK, PNG, UL, UM
Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where ...wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.
Microplastic pollution represents a side-effect stemming from a global plastic waste mismanagement problem and includes degraded particles or mass produced plastic particles less than 5 mm in largest ...dimension. The small nature of microplastics gives this area of pollution different
environmental concerns than general plastic waste in the environment. The biological toxicity of particles, their internal components, and their surface level changes all present opportunities for these particles to adversely affect the environment around them. Thus, it is necessary to review
the current literature surrounding this topic and identify areas where the study of microplastic can be pushed forward. Here we present current methods in studying microplastics, some of the ways by which microplastics affect the environment and attempt to shed light on how this research can
continue. In addition, we review current recycling methods developing for the processing of mixed-plastic waste. These methods, including hydrothermal processing and solvent extraction, provide a unique opportunity to separate plastic waste and improve the viability of the plastics recycling
industry.
The widespread presence of microplastics (MPs) in aquatic environments has become a significant concern, with freshwater sediments acting as terminal sinks, rapidly picking up these emerging ...anthropogenic particles. However, the accumulation, transport, degradation and biochemical impacts of MPs in freshwater sediments remain unresolved issues compared to other environmental compartments. Therefore, this paper systematically revealed the spatial distribution and characterization information of MPs in freshwater (rivers, lakes, and estuaries) sediments, in which small-size (<1 mm), fibers, transparent, polyethylene (PE), and polypropylene (PP) predominate, and the average abundance of MPs in river sediments displayed significant heterogeneity compared to other matrices. Next, the transport kinetics and drivers of MPs in sediments are summarized, MPs transport is controlled by the particle diversity and surrounding environmental variability, leading to different migration behaviors and transport efficiencies. Also emphasized the spatio-temporal evolution of MPs degradation processes and biodegradation mechanisms in sediments, different microorganisms can depolymerize high molecular weight polymers into low molecular weight biodegradation by-products via secreting hydrolytic enzymes or redox enzymes. Finally, discussed the ecological impacts of MPs on microbial-nutrient coupling in sediments, MPs can interfere with the ecological balance of microbially mediated nutrient cycling by altering community networks and structures, enzyme activities, and nutrient-related functional gene expressions. This work aims to elucidate the plasticity characteristics, fate processes, and potential ecological impact mechanisms of MPs in freshwater sediments, facilitating a better understanding of environmental risks of MPs in freshwater sediments.
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•MPs pollution in freshwater sediments is spatially and temporally heterogeneous.•Hydrodynamic, sediment geochemistry and biological factors control MPs transport.•Microbial-induced biodegradation is more critical for MPs degradation in sediments.•Biodegradable MPs exert greater impact on nutrient cycling in sediments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, the transverse indentation test was applied to simulate the damage caused by impact to the carbon fiber‐reinforced plastics (CFRP)/Al hybrid tube, and composites patch repair ...technology was used to repair the hybrid tube with different damage degrees. The effects of width and ply‐number of the patch on failure behavior and crashworthiness under axial load were investigated. It was concluded that the technology can effectively reduce stress concentration around the indentation and then improve compressive strength. Increasing the ply‐number of the patch can mitigate the failure mode of med‐length collapse of the hybrid tube and can effectively improve the crashworthiness indicators. The optimal repair strategy increased energy absorption by 54.02% and mean crushing force by 53.66%. However, the improvement of failure behavior by the ply‐number is limited by patch width. Acoustic emission and infrared thermography technologies were used to further analyze the damage characteristics and damage evolution of the hybrid tubes in pre‐crushing stage. It was found that the crushing form of the middle collapse tended to produce a more intense acoustic emission response and higher temperature change than that of the end crushing. In engineering practice, it provides a valuable reference for the reasonable repair of composite tubular structures and their hybrid structures.
Highlights
Composite repair technology is used for the repair of CFRP/Al hybrid tubes.
The effects of ply‐number and width of patch on repair quality are studied.
The technology can effectively improve residual crashworthiness of structure.
The improvement of failure behavior by ply‐number is limited by patch width.
The damage behavior of various crushing forms can be revealed by AE and IR.
The effect of composite patch repair on failure behavior and crashworthiness of composites‐metal hybrid tubes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Polystyrene (PS) is frequently used in the plastics industry. However, its structural stability and difficulty to break down lead to an abundance of plastic waste in the environment, resulting in ...micro-nano plastics (MNPs). As MNPs are severe hazards to both human and environmental health, it is crucial to develop innovative treatment technologies to degrade plastic waste. The biodegradation of plastics by insect gut microorganisms has gained attention as it is environmentally friendly, efficient, and safe. However, our knowledge of the biodegradation of PS is still limited. This review summarizes recent research advances on PS biodegradation by gut microorganisms/enzymes from insect larvae of different species, and schematic pathways of the degradation process are discussed in depth. Additionally, the prospect of using modern biotechnology, such as genetic engineering and systems biology, to identify novel PS-degrading microbes/functional genes/enzymes and to realize new strategies for PS biodegradation is highlighted. Challenges and limitations faced by the application of genetically engineered microorganisms (GEMs) and multiomics technologies in the field of plastic pollution bioremediation are also discussed. This review encourages the further exploration of the biodegradation of PS by insect gut microbes/enzymes, offering a cutting-edge perspective to identify PS biodegradation pathways and create effective biodegradation strategies.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Identification and characterisation of microplastic (MP) is a necessary step to evaluate their concentrations, chemical composition and interactions with biota. MP ≥10μm diameter filtered from below ...the sea surface in the European and subtropical North Atlantic were simultaneously identified by visual microscopy and Raman micro-spectroscopy. Visually identified particles below 100μm had a significantly lower percentage confirmed by Raman than larger ones indicating that visual identification alone is inappropriate for studies on small microplastics. Sixty-eight percent of visually counted MP (n=1279) were spectroscopically confirmed being plastic. The percentage varied with type, colour and size of the MP. Fibres had a higher success rate (75%) than particles (64%). We tested Raman micro-spectroscopy applicability for MP identification with respect to varying chemical composition (additives), degradation state and organic matter coating. Partially UV-degraded post-consumer plastics provided identifiable Raman spectra for polymers most common among marine MP, i.e. polyethylene and polypropylene.
•Misidentification problems in visual microscopic analysis of small microplastic•Development of Raman measurement procedures for increased analysis certainty applicable by non-expert users•Application of Raman spectroscopy tested for weathered microplastic identification
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•Anaerobic co-digestion of PLA or PHB plastics with biowastes is feasible at pilot scale.•At an OLR of 2.5 g vS L-1 d-1, the reactor only fed with biowaste was not stable.•Addition of ...biodegradable plastics resulted in a more stable process.•PLA or PHB in the biogas plant feeding, did not affect the digestate quality.
The development of selective biowaste collection in most European countries provides new opportunities for the anaerobic digestion sector. In parallel, extensive development of biodegradable plastics like polylactic-acid (PLA) and polyhydroxybutyrate (PHB), which facilitates the replacement of conventional plastics, has taken place in the past decade. This study investigated anaerobic co-digestion in semi-continuous reactors of biowastes (75 % Volatil Solids) and biodegradable plastics (25 % Volatil Solids, PLA and PHB). PHB was estimated to be fully biodegraded in the reactors. By contrast, PLA accumulated in the reactor, and an average biodegradation of 47.6 ± 17.9 % was estimated during the third hydraulic retention time. Pretreatment of PLA, by thermo-alkaline hydrolysis at 70 °C, with 2.5 w/v of Ca(OH)2 for 48 h, improved the biodegradation yield of PLA to 77.5 ± 9.3 %. Finally, it was highlighted that PLA or PHB addition to the feed did not further affect the agronomic properties of the digestate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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