Search Results (1,943)

The problem of marine plastic pollution is multifaceted and poses a serious threat to the ecosystem and human health. This work is the first investigation of mesoplastics (MEPs, 5 mm–2.5 cm) along the most representative beaches of the whole Mediterranean coast of Morocco. Surface sediment samples (0–5 cm), with 3 replicates each, were collected from thirty-three beaches to identify mesoplastic item characteristics (concentration, weight, type, size, color, and nature). The samples were collected between October and November 2021 and a total of 1998 mesoplastics (59.99 g kg⁻¹) were collected from the thirty-three beaches studied. The average concentrations ranged from 20.18 ± 13.93 MEP kg⁻¹ to 0.61 ± 0.61 g kg⁻¹, showing a great variability within each beach and between the beaches investigated. Mesoplastic fragments accounted for 43.92% of the total mesoplastic items, showed sizes from 5 to 10 mm (56.64%) and were predominantly white/transparent (43.36%). Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), and Polyvinyl chloride (PVC) were the most common polymers. The present results revealed a moderate level of mesoplastics pollution along the beaches investigated. Fishing, coastal activities, and wastewater discharges were probably the main sources. Furthermore, this study is likely to serve as a scientific baseline for monitoring and tracking mesoplastic pollution on Moroccan beaches. Full article

Conventional plastics are widely utilised across industrial sectors and in consumer products. However, the growing use of plastics has led to plastic pollution, including the formation of nanoplastics (NPs), which are harmful to aquatic organisms. Bioplastics are emerging alternatives. They are renewable and/or biodegradable and are supposed to be more environmentally friendly. However, the toxicity and environmental fate of bioplastics are not yet fully understood. This study evaluated the toxicity and fate of commercially available plain or fluorescent polylactic acid (PLA) NPs (250 nm) on aquatic organisms. Confocal microscopy demonstrated the uptake of fluorescent PLA NPs by the test organisms, marine rotifers (Brachionus plicatilis), brine shrimps (Artemia salina) and zebrafish (Danio rerio) embryos. However, the results of the bioassays indicate that plain PLA NPs did not induce acute toxicity in either of the two zooplankton species and did not cause substantial mortality, malformations, or hatching delays in zebrafish embryos at the tested concentrations (up to 100 mg/L). However, brine shrimp showed a significant decrease in ingestion capability. The biochemical biomarkers, catalase activity induction, as an indicator of oxidative stress, and acetylcholinesterase inhibition, as a marker of neurotoxicity, showed no significant alterations compared to the control of both zooplankton species and that of zebrafish embryos. Overall, the findings suggest a pattern of no acute and low sublethal toxicity for the tested plain PLA NPs in the studied organisms. Nonetheless, further research is imperative to comprehensively assess the environmental fate of bioplastics found in various consumer products, as these may contain harmful chemical additives, as well as the effects of prolonged exposure and their impact on physiological parameters, ensuring informed decisions before their widespread commercialisation and presence in the environment. Full article

Traditional cotton field plastic film residue monitoring relies on manual sampling, with low efficiency and limited accuracy; therefore, large-scale nondestructive monitoring is difficult to achieve. A UAV-based prediction method for shallow plastic film residue pollution in cotton fields that uses RDT-Net and machine learning is proposed in this study. This study focuses on the weight of residual plastic film in shallow layers of cotton fields and UAV-captured surface film images, establishing a technical pathway for drone image segmentation and weight prediction. First, the images of residual plastic film in cotton fields captured by the UAV are processed via the RDT-Net semantic segmentation model. A comparative analysis of multiple classic semantic segmentation models reveals that RDT-Net achieves optimal performance. The local feature extraction process in ResNet50 is combined with the global context modeling advantages of the Transformer and the Dice-CE Loss function for precise residue segmentation. The mPa, F1 score, and mIoU of RDT-Net reached 95.88%, 88.33%, and 86.48%, respectively. Second, a correlation analysis was conducted between the coverage rate of superficial residual membranes and the weight of superficial residual membranes across 300 sample sets. The results revealed a significant positive correlation, with R² = 0.79635 and PCC = 0.89239. Last, multiple machine learning prediction models were constructed on the basis of plastic film coverage. The ridge regression model achieved optimal performance, with a prediction R² of 0.853 and an RMSE of 0.1009, increasing accuracy in both the segmentation stage and prediction stage. Compared with traditional manual sampling, this method substantially reduces the monitoring time per cotton field, significantly decreases monitoring costs, and prevents soil structure disruption. These findings address shortcomings in existing monitoring methods for assessing surface plastic film content, providing an effective technical solution for large-scale, high-precision, nondestructive monitoring of plastic film pollution on farmland surfaces and in the plow layer. It also offers data support for the precise management of plastic film pollution in cotton fields. Full article

This study addresses the critical issue of environmental pollution from plastic waste by investigating an effective chemical recycling method for polyethylene terephthalate (PET) via neutral catalytic hydrolysis. We utilized a recoverable and regenerable composite catalyst based on cracking zeolite and γ-Al₂O₃, which possesses both Brønsted and Lewis acidic sites that facilitate the depolymerization of PET into its constituent monomers, terephthalic acid (TPA) and ethylene glycol (EG). This investigation reveals that the catalytic performance is strongly dependent on the total acid site concentration and the specific nature of these sites. A key finding is that a balanced acidic profile with a high proportion of Brønsted acid sites is crucial for enhancing PET hydrolysis attributed to a significant decrease in the activation energy of the reaction. The experiments were conducted in a stirred stainless-steel autoclave reactor, where key parameters such as temperature (210–230 °C), the PET-to-water ratio (1:2 to 1:5), and reaction time were systematically varied. Under optimal conditions of 210 °C and a 6 h reaction time, the process achieved near-complete PET depolymerization (99.5%) and a high TPA yield (90.24%). The catalyst demonstrated remarkable recyclability, maintained its activity over multiple cycles and was easily regenerated. Furthermore, the recovered TPA was of high quality, with a purity of 98.74% as confirmed by HPLC, and exhibited a melt crystallization temperature 14 °C lower than that of the commercial standard. These results not only demonstrate the efficiency and sustainability of neutral catalytic hydrolysis using zeolite/alumina composites but also provide valuable insights for designing advanced catalysts with tunable acidic properties. By demonstrating the importance of tuning acidic properties, specifically the balance between Brønsted and Lewis sites, this work lays a foundation for developing more effective catalysts that can advance circular economy goals for PET recycling. Full article

Food packaging serves a pivotal role in daily life, facilitating the efficient transportation of food and extending its shelf life. Petroleum-derived plastic packaging is extensively employed; however, its non-biodegradable nature poses significant environmental pollution and ecological degradation. Natural polymers (e.g., proteins such as gelatin and corn gluten protein; polysaccharides including pectin, chitosan, starch, cellulose, and alginate) and synthetic polymers (e.g., polyvinyl alcohol, polylactic acid, and polyhydroxyalkanoates) can be utilized to fabricate food packaging films, thereby achieving green and eco-friendly objectives. Nevertheless, the inferior mechanical strength and inadequate antibacterial activity of biopolymer-based packaging have restricted their practical applications. In recent years, nanomaterials (e.g., nanoparticles, nanotubes, nanofibers, and nanosheets) have been employed to enhance the performance of food packaging, emerging as a research hotspot. Notably, nanoparticles possess unique properties, including a high specific surface area, excellent dispersibility, and multifunctionality, which enables them to be easily incorporated into film matrices. Owing to their unique chemical structures, nanoparticles form strong interactions with film matrices, leading to a denser spatial structure. This not only markedly enhances the mechanical strength of the films, but also simultaneously improves their antibacterial and antioxidant capabilities. This review classifies and summarizes common nanomaterials based on their chemical compositions, providing a theoretical foundation and technical reference for the future development and application of nanomaterials in the field of bio-based active food packaging. Full article

Plastic mulch residues threaten soil fertility and contribute to microplastic pollution, creating an urgent need for accurate, rapid mapping of plastic-mulched land (PML). This study presents a novel method for detecting PML from GF-2 imagery by introducing the second component of the K-T transform as a PML-enhancement feature to compensate for the sensor’s limited spectral bands. The K-T component was fused with selected texture metrics and the original spectral bands, and an object-oriented classification framework was applied to delineate PML. Validation shows that the proposed method achieves high identification accuracy for PML and good transferability, with accuracies exceeding 90% across the four selected study areas. Moreover, the method demonstrates strong temporal stability: classification accuracies exceeded 90% for two different time periods within the same study area. Compared with methods reported in previous studies, our approach attains comparable accuracy while offering higher classification efficiency. Overall, the proposed method enables accurate PML identification from GF-2 imagery and provides a valuable reference for agricultural planning and ecological protection. Full article

Polyethylene terephthalate (PET) is one of the most widely used plastics globally, and its poor post-consumer management poses serious risks to the environment and human health. Tackling this issue requires innovative strategies that combine recycling and sustainable manufacturing with the principles of the circular economy. This study addresses this challenge by investigating the use of recycled PET, along with reverse logistics, to produce a cell phone holder through additive manufacturing (AM). Characterization was performed using differential scanning calorimetry, thermogravimetric analysis, intrinsic viscosity measurements, and mechanical tensile tests. Environmental and circular performance were evaluated using Life Cycle Assessment (LCA) and the Material Circularity Indicator (MCI), comparing production with 100% virgin PET resin and 100% recycled PET resin. The results showed that the recycled route achieved a tensile strength of 37.7 MPa, with 7.6% strain before rupture, and thermal analysis confirmed its stability during processing. The LCA revealed a 12% reduction in overall environmental impacts when recycled PET replaced virgin resin, with electricity consumption identified as the main critical point. The circularity assessment suggested potential savings of up to 70% if recycled PET products are reprocessed at the end of their life cycles. These findings demonstrate that combining open-loop recycling with additive manufacturing (AM) can effectively turn waste into high-quality, value-added products, advancing circularity and sustainable material innovation. Full article

Plastics play a pivotal role in various industries owing to their versatility in engineering their physical, mechanical, and chemical properties while exploiting their remarkable durability, light-weight nature, and cost-effectiveness. Yet, their widespread use has led to the pollution of Earth’s water systems. Over time, plastic waste degrades into microplastics, particles smaller than 5 mm. Recent studies have highlighted the growing concerns associated with microplastics, especially in bottled beverages, including bottled water, with associated hazards still in the very early stages of being fully understood. Furthermore, the global understanding of the extent of microplastic contamination in the environment and along the food chain remains limited. This study aimed to detect, quantify, and characterise microplastics in bottled drinking water produced and sold in Malta. Samples from five brands were filtered, stained with Nile red, and quantified using fluorescence microscopy. The average microplastic concentration was found to be 35,877 ± 23,542 particles per litre, with 84% of samples exhibiting contamination, which was noted to be statistically significant. The average particle diameter was measured to be 2.3696 ± 0.0035 µm. Raman spectroscopy was used to chemically characterise 10 larger particles per brand (i.e., 50 samples), identifying the presence of cellulose, polyurethane, polymethyl methacrylate, polyethylene, and smaller quantities of other polymers. Morphological analysis classified 36 of the larger particles as fragments and 14 as fibres. Excluding laboratory-introduced contamination, the primary source of microplastic contamination in the analysed bottled water was traced to the bottle caps. Full article

We investigated the presence, chemical/morphological characteristics, and distribution of microplastics (MPs, 1–5 mm) in three beaches located at the southeast of the Bay of Biscay, an area where this kind of study is scarce. Sampling was carried out in March 2022/2023 and October 2023/2024. The microplastics found were chemically characterised by Raman spectroscopy and morphologically described (size, shape, and colour) by visual observation. A total of 836 MPs were found, with Atxabiribil beach showing the highest mean concentrations (15 MPs kg⁻¹), followed by Sonabia (10 MPs kg⁻¹) and Gorliz (3 MPs kg⁻¹). The highest concentrations were recorded in March 2023 and the lowest ones in March 2024, with no clear seasonal trend. Foam, fragments, and pellets were dominant, although filaments, films, and fibres were also found. White MPs were the most abundant, followed by blue and black items. Polyethylene, polypropylene, and polystyrene, in this order, were the most common polymers. In conclusion, we report here valuable information about the abundance and characteristics of MPs in beaches located in an area poorly investigated previously. The results obtained underline the importance of the implementation of regular monitoring campaigns to estimate the impact and consequences that plastic pollution has in our coastal environments. Full article

The ubiquitous environmental pollution with micro- and nano-sized plastic particles (MNPs) is a current and significant problem today. At the same time, lung cancer is responsible for the largest number of cancer-related deaths worldwide. Many research groups have investigated the relationship between lung cancer development and exposure to MNPs in recent years. Studies have demonstrated that these particles could enter the respiratory system in a variety of ways—both directly through inhaled air and through the bloodstream, and through internalization in the intestines and other digestive organs. Data regarding the possibility of their aggregation in the respiratory system, thyroid gland, and brain are also concerning, as the harmful effects of MNPs have been proven to depend on their concentration and exposure time. The primary response of cells to plastic particles is an increase in oxidative stress. This is generated both by the cell itself (especially macrophages) and induced by damage caused by mechanical damage to cellular organelles by MNPs. The consequences of MNP exposure can include metabolic disturbances, DNA damage, and mutations, ultimately inducing neoplastic transformation in healthy cells. This can lead to changes in tissue architecture and increase their susceptibility to other pathogens, such as pathogenic microorganisms or heavy metals. These, in turn, can be internalized along with MNPs, forming a corona surrounding them. Full article

Plastics have become a ubiquitous feature of modern life, with their presence continually increasing. This widespread use has led to the global proliferation of plastics, including contamination of aquatic environments. This review focuses on microplastics—plastic particles less than 5 mm in size—in the Northern Gulf of Mexico. The central objective was to evaluate the abundance and potential impacts of microplastics in the region. Findings appear to indicate that microplastic concentrations in the water are below global averages, while concentrations in shoreline sediments are slightly above average. Although it appears fewer biological specimens contain microplastics in this region, the number of plastic particles per specimen appears higher compared to global observations. Microplastics significantly delay the transition of dissolved organic matter to particulate organic matter (by more than 200%), bioaccumulate in organisms, serve as adsorption surfaces for toxins and pollutants, and cause a range of biological effects. Further research is necessary to accurately quantify microplastic pollution and evaluate its ecological and environmental impacts. Full article

Nanoplastics have emerged as widespread environmental contaminants with toxicological properties that differ from those of microplastics. While existing reviews often examine their effects on specific organisms, they rarely provide direct comparisons with microplastics. This review aims to comprehensively assess the toxic effects of nanoplastics on animals, with a comparative perspective highlighting their distinctions from microplastics. In mammals, nanoplastics cross the blood–brain barrier and induce oxidative stress, neuroinflammation, mitochondrial dysfunction, and synaptic disruption, with consequences ranging from cognitive impairment to Parkinson’s disease-like neurodegeneration. They also impair liver, kidney, intestinal, pancreatic, and reproductive function, with evidence of transgenerational toxicity. In aquatic organisms such as fish, crustaceans, bivalves, and aquatic invertebrates, nanoplastics compromise growth, immunity, reproduction, and metabolism, while in terrestrial invertebrates they cause gut toxicity, mitochondrial damage, immune suppression, and heritable defects. Across taxa, the dominant mechanisms involve oxidative stress, apoptosis, inflammation, and interference with metabolic and signaling pathways. Comparisons with microplastics reveal that while both particle types are harmful, nanoplastics generally exert stronger and more systemic effects due to higher bioavailability, cellular uptake, and molecular reactivity. Microplastics primarily impose mechanical stress, whereas nanoplastics disrupt cellular homeostasis at lower exposure levels, often acting at the subcellular level. Evidence also indicates size-, surface chemistry-, and concentration-dependent effects, with smaller and functionalized nanoplastics exhibiting heightened toxicity. Despite growing knowledge, significant gaps remain in cross-size comparative studies, long-term and multigenerational assessments, trophic transfer analyses, and investigations involving environmentally derived nanoplastics. Addressing these gaps is critical for advancing ecological risk assessment and developing mitigation strategies against plastic pollution. Full article

Globally, little is known about the dispersal of microplastics (MP) and anthropogenic particles (AP) via atmospheric deposition (AD) into water bodies. Correlating AD to the large number of MP in estuaries is challenging but an important first step toward reducing this form of pollution. A previously published model of the surface waters of the Indian River Lagoon (IRL, east central coast of Florida, USA) estimated it contained 1.4 trillion microplastics. To determine if AD could produce this much plastic deposition, we deployed passive AD collectors throughout a 145 km² area at three site types with assistance from citizen scientists. We predicted that the rate of deposition of MP and AP would be greatest in residential areas, intermediate within a national park, and lowest on intertidal oyster reefs. Moreover, we predicted Florida’s wet season and individual rain events would increase deposition based on the published literature. Over 14 months, deposition averaged 1224 MP/m²/d; extrapolated, this yields 1.1 trillion MP for the lagoon-wide total deposition estimate (95% CI: 0.86–1.39 trillion MP). This value suggests that AD may represent an important pathway for MP to enter this estuary. More MP were deposited during rain events and in the wet season, with no differences among sites. Overall, our results provide important data for understanding AD of MP and AP in estuaries. Full article

The widespread use of plastics has caused severe environmental pollution, driving interest in biodegradable alternatives like polylactic acid (PLA). However, incomplete degradation of biodegradable plastics under natural conditions may generate micro/nanoplastics that could exacerbate ecological risks. This study investigated the combined effects of UV-aged microplastics from biodegradable PLA and conventional PET, along with sulfamethoxazole (SMX), on the conjugative transfer of antibiotic resistance genes (ARGs) between bacteria. Using UV aging to simulate environmental weathering, the microplastic morphology, adsorption behavior, and interaction with SMX were characterized. The study further evaluated the bacterial viability, ROS level, membrane permeability, and the expression of conjugative transfer-related genes to elucidate the underlying mechanisms. Results showed that aged PLA released significantly more nanoplastics and exhibited higher adsorption affinity for SMX than PET. Combined exposure to aged PLA and SMX significantly enhanced ARG transfer frequency by approximately 14.5-fold compared to the control. Mechanistic studies revealed that this promotion was associated with increased intracellular ROS levels, elevated membrane permeability, and upregulation of conjugative related genes. These findings underscore that biodegradable plastics, after environmental aging, may pose greater ecological risks than conventional plastics, and highlight the importance of considering environmental aging in the risk assessment of plastics. Full article

Plastic waste in river systems represents a major pathway of marine pollution, with rivers estimated to contribute up to 80% of the plastic entering the ocean. This study introduces a deep learning framework with preprocessing for automated detection and tracking of floating plastic waste (macroplastics) in the urban canals of the Chao Phraya River, Thailand. Unlike previous approaches that rely on site-specific retraining or model modification, our method employs a YOLO-based detection model integrated with DeepSORT (Deep Simple Online and Realtime Tracking). The model, initially trained on laboratory flume images, was adapted to real river conditions through a three-step preprocessing pipeline comprising skew correction, background removal, and object region extraction. Experiments on 2000 canal images demonstrated that preprocessing improved the mean Average Precision (mAP) from 0.74 to 0.85, with notable gains for categories such as foam and paper. Testing with a more advanced YOLO architecture further enhanced accuracy, indicating that preprocessing and model upgrades are complementary. These findings suggest that reliable detection and quantification of floating waste can be achieved without retraining. The proposed framework provides a scalable and cost-effective solution for monitoring in data-limited regions, contributing to efforts to mitigate riverine and marine plastic pollution. Future work will address the remaining limitations, as detection performance is still influenced by strong reflections, motion blur, and occlusion, occasionally resulting in missed detections. Full article