Soil viral-host interactions regulate microplastic-dependent carbon storage.

Microplastic is globally regarded as an important factor impacting biogeochemical cycles, yet our understanding of such influences is limited by the uncertainties of intricate microbial processes. By multiomics analysis, coupled with soil chemodiversity characterization and microbial carbon use efficiency (CUE), we investigated how microbial responses to microplastics impacted soil carbon cycling in a long-term field experiment. We showed that biodegradable microplastics promoted soil organic carbon accrual by an average of 2.47%, while nondegradable microplastics inhibited it by 17.4%, as a consequence of the virus-bacteria coadaptations to the microplastics disturbance. In the relevant functional pathways, nondegradable microplastics significantly (P < 0.05) enhanced the abundance and transcriptional activity related to complex carbohydrate metabolism, whereas biodegradable microplastics significantly (P < 0.05) promoted functions involved in amino acid metabolism and glycolysis. Accordingly, viral lysis enhanced in nondegradable microplastics treatments to introduce more complex organic compounds to soil dissolved organic matters, thus benefiting the oligotrophs with high carbon metabolic capabilities in exploitation competition. In contrast, biodegradable microplastics enriched viral auxiliary metabolic genes of carbon metabolism through "piggyback-the-winner" strategy, conferring to dominant copiotrophs, enhanced substrate utilization capabilities. These virus-host interactions were also demonstrated in the corresponding soil plastisphere, which would alter microbial resource allocation and metabolism via CUE, affecting carbon storage consequently. Overall, our results underscore the importance of viral-host interactions in understanding the microplastics-dependent carbon storage in the soil ecosystem.

Selective colonization of microplastics, wood and glass by antimicrobial-resistant and pathogenic bacteria.

The Plastisphere is a novel niche whereby microbial communities attach to plastic debris, including microplastics. These communities can be distinct from those found in the surrounding environment or those attached to natural substrates and may serve as a reservoir of both pathogenic and antimicrobial-resistant (AMR) bacteria. Owing to the frequent omission of appropriate comparator particles (e.g. natural substrates) in previous studies, there is a lack of empirical evidence supporting the unique risks posed by microplastics in terms of enrichment and spread of AMR pathogens. This study investigated selective colonization by a sewage community on environmentally sampled microplastics with three different polymers, sources and morphologies, alongside natural substrate (wood), inert substrate (glass) and free-living/planktonic community controls. Culture and molecular methods (quantitative polymerase chain reaction (qPCR)) were used to ascertain phenotypic and genotypic AMR prevalence, respectively, and multiplex colony PCR was used to identify extra-intestinal pathogenic Escherichia coli (ExPECs). From this, polystyrene and wood particles were found to significantly enrich AMR bacteria, whereas sewage-sourced bio-beads significantly enriched ExPECs. Polystyrene and wood were the least smooth particles, and so the importance of particle roughness on AMR prevalence was then directly investigated by comparing the colonization of virgin vs artificially weathered polyethylene particles. Surface weathering did not have a significant effect on the AMR prevalence of colonized particles. Our results suggest that the colonization of plastic and non-plastic particles by AMR and pathogenic bacteria may be enhanced by substrate-specific traits.

Ameliorating arsenic and PVC microplastic stress in barley (Hordeum vulgare L.) using copper oxide nanoparticles: an environmental bioremediation approach.

The present study investigates the impact of varying concentrations of PVC microplastics (PVC-MPs) - specifically 0 (no PVC-MPs), 2, and 4 mg L- 1 -alongside different arsenic (As) levels of 0 (no As), 150, and 300 mg kg- 1 in the soil, with the concurrent application of copper oxide-nanoparticles (CuO-NPs) at 0 (no CuO -NPs), 25 and 50 µg mL- 1 to barley (Hordeum vulgare L.) plants. This research primarily aims to assess plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators, as well as the response of various antioxidants (both enzymatic and non-enzymatic) and their relevant genes expression, proline metabolism, the AsA-GSH cycle, and cellular fractionation within the plants. The findings showed that increased levels of PVC-MPs and As stress in the soil significantly reduced plant growth and biomass, photosynthetic pigments, and gas exchange characteristics. Additionally, PVC-MPs and As stress increased oxidative stress in the roots and shoots, as evidenced by elevated levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL), which in turn stimulated the production of various enzymatic and non-enzymatic antioxidants, gene expression, and sugar content. Furthermore, a notable increase in proline metabolism, the AsA-GSH cycle, and cellular pigmentation was observed. Conversely, the application of CuO-NPs resulted in a substantial improvement in plant growth and biomass, gas exchange characteristics, and the activity of enzymatic and non-enzymatic antioxidants, along with a reduction in oxidative stress. Additionally, CuO-NPs enhanced cellular fractionation while decreasing proline metabolism and the AsA-GSH cycle in H. vulgare plants. These outcomes provide new insights into sustainable agricultural practices and offer significant potential in addressing the critical challenges of heavy metal contamination in agricultural soils.

Photoreforming of Microplastics: Challenges and Opportunities for Sustainable Environmental Remediation.

Plastics are widely used in daily lives, but unfortunately, their inadequate recycling practices have led to the accumulation of microplastics in the environment, posing a threat to public health. The existing methods for treating microplastics are energy-intensive and environmentally damaging. In this context, photoreforming has emerged as a sustainable solution to address the microplastic crisis by simultaneously recycling them into value-added chemicals. This review presents a comprehensive overview of the application of photoreforming for upcycling microplastic. The underlying mechanisms of photoreforming reaction are discussed, followed by the exploration of recent advancements and innovative strategies in photoreforming techniques with particular emphasis on their real-world applications and potential for large-scale implementation. Also, critical factors influencing the efficiency of microplastic photoreforming are identified, providing guidance for further research and optimization.

Liquidlike, Low-Friction Polymer Brushes for Microfibre Release Prevention from Textiles.

During synthetic textile washing, rubbing between fibres or against the washing machine, exacerbated by the elevated temperature, initiates the release of millions of microplastic fibres into the environment. A general tribological strategy is reported that practically eliminates the release of microplastic fibres from laundered apparel. The two-layer fabric finishes combine low-friction, liquidlike polymer brushes with "molecular primers", that is, molecules that durably bond the low-friction layers to the surface of the polyester or nylon fabrics. It is shown that when the coefficient of friction is below a threshold of 0.25, microplastic fibre release is substantially reduced, by up to 96%. The fabric finishes can be water-wicking or water-repellent, and their comfort properties are retained after coating, indicating a tunable and practical strategy toward a sustainable textile industry and plastic-free oceans and marine foodstuffs.

Microplastics are detected in bull epididymal sperm and polystyrene microparticles impair sperm fertilization.

An increase in global infertility has coincided with the accumulation of microplastics (MPs) in the environment. This trend is particularly troubling because only 10% of male infertility cases can be attributed to identifiable causes, leaving a knowledge gap in our understanding of their underlying factors. To bridge this, it is important to explore the connection between the accumulation of MPs and the observed decline in male fertility. We assessed the presence of microplastics in epididymal sperm from bulls and used it as baseline concentrations for sperm exposure. MPs were detected in all epidydimal sperm (ES) samples, with a mean concentration of 0.37 µg mL-1. Next, to investigate the effects of MPs on fertility, bovine sperm was exposed to three different concentrations of a mixture of 1.1, 0.5, and 0.3 µm polystyrene (PS) beads: (1) 0.7 µg mL-1, blood concentration of PS in cows (bPS); (2) 0.37 µg mL-1, based on the concentration of total MPs found in ES (esMP); and (3) 0.026 µg mL-1, based on the concentration of PS found in ES (esPS). All sperm samples incubated with PS exhibited reduced motility compared with the control at 0.5 h. However, PS exposure did not affect acrosome integrity or induced oxidative stress. Embryos produced from sperm exposed to PS had reduced blastocyst rates, in addition to increased ROS formation and apoptosis. By employing physiological exposure, this research provided evidence of MPs in bovine epididymal sperm and demonstrated the detrimental effect of PS on sperm functionality.

Flavonoids Mitigate Nanoplastic Stress in Ginkgo biloba.

Microplastics/nanoplastics are a top global environmental concern and have stimulated surging research into plant-nanoplastic interactions. Previous studies have examined the responses of plants to nanoplastic stress at various levels. Plant-specialized (secondary) metabolites play crucial roles in plant responses to environmental stress, whereas their roles in response to nanoplastic stress remain unknown. Here, we systematically examined the physiological and biochemical responses of Ginkgo biloba, a species with robust metabolite-driven defenses, to polystyrene nanoplastics (PSNPs). PSNPs negatively affected seedling growth and induced phytotoxicity, oxidative stress, and nuclear damage. Notably, PSNPs caused significant flavonoid accumulation, which enhances plant tolerance and detoxification against PSNP stress. To determine whether this finding is universal in plants, we subjected Arabidopsis, poplar, and tomato to PSNP stress and verified the common response of enhanced flavonoids across these species. To further confirm the role of flavonoids, we employed genetic transformation and staining techniques, validating the importance of flavonoids in mitigating excessive oxidative stress induced by NPs. Matrix analysis of transgenic plants with enhanced flavonoids further demonstrated altered downstream pathways, allocating more energy towards resilience against nanoplastic stress. Collectively, our results reveal the flavonoid multifaceted roles in enhancing plant resilience to nanoplastic stress, providing new knowledge about plant responses to nanoplastic contamination.

On the behavior of sub-micrometer polystyrene particles subjected to AC insulator-based dielectrophoresis.

Polymer beads, especially polystyrene particles, have been extensively used as model species in insulator-based dielectrophoresis (iDEP) studies. Their use in alternating current iDEP (AC-iDEP) is less explored; however, an assessment in the low-frequency regime (≤10 kHz) allows to link surface conduction effects with the surface properties of polymer particles. Here, we provide a case study for various experimental conditions assessing sub-micrometer polystyrene particles with AC-iDEP and link to accepted surface conduction theory to predict and experimentally verify the observed AC-iDEP trapping behavior based on apparent zeta potential and solution conductivity. We find excellent agreement with the theoretical predictions, but also the occurrence of concentration polarization electroosmotic flow under the studied conditions, which have the potential to confound acting dielectrophoresis conditions. Furthermore, we study a case relevant to the assessment of microplastics in human and animal body fluids by mimicking the protein adsorption of high abundant proteins in blood by coating polystyrene beads with bovine serum albumin, a highly abundant protein in blood. Theoretical predictions and experimental observations confirm a difference in observed AC-iDEP behavior between coated and non-coated particles, which might be exploited for future studies of microplastics in blood to assess their exposure to humans and animals.

Environmental impact of microplastics and potential health hazards.

Microscopic plastic (microplastic) pollutants threaten the earth's biodiversity and ecosystems. As a result of the progressive fragmentation of oversized plastic containers and products or manufacturing in small sizes, microplastics (particles of a diameter of 5 mm with no lower limit) are used in medicines, personal care products, and industry. The incidence of microplastics is found everywhere in the air, marine waters, land, and even food that humans and animals consume. One of the greatest concerns is the permanent damage that is created by plastic waste to our fragile ecosystem. The impossibility of the complete removal of all microplastic contamination from the oceans is one of the principal tasks of our governing body, research scientists, and individuals. Implementing the necessary measures to reduce the levels of plastic consumption is the only way to protect our environment. Cutting off the plastic flow is the key remedy to reducing waste and pollution, and such an approach could show immense significance. This review offers a comprehensive exploration of the various aspects of microplastics, encompassing their composition, types, properties, origins, health risks, and environmental impacts. Furthermore, it delves into strategies for comprehending the dynamics of microplastics within oceanic ecosystems, with a focus on averting their integration into every tier of the food chain.

Fish microplastic ingestion may induce tipping points of aquatic ecosystems.

Microplastics can be ingested by a wide range of aquatic animals. Extensive studies have demonstrated that microplastic ingestion-albeit often not lethal-can affect a range of species life-history traits. However, it remains unclear how the sublethal effects of microplastics on individual levels scale up to influence ecosystem-level dynamics through cascading trophic interactions. Here we employ a well-studied, empirically fed three-species trophic chain model, which was parameterized to mimic a common type of aquatic ecosystems to examine how microplastic ingestion by fish on an intermediate trophic level can produce cascading effects on the species at both upper and lower trophic levels. We show that gradually increasing microplastics in the ingested substances of planktivorous fish may cause population structure effects such as skewed size distributions (i.e. reduced average body length vs. increased maximal body size), and induce abrupt declines in fish biomass and reproduction. Our model analysis demonstrates that these abrupt changes correspond to an ecosystem-level tipping point, crossing which difficult-to-reverse ecosystem degradation can happen. Importantly, microplastic pollution may interact with other anthropogenic stressors to reduce safe operating space of aquatic ecosystems. Our work contributes to better understanding complex effects of microplastic pollution and anticipating tipping points of aquatic ecosystems in a changing world. It also calls attention to an emerging threat that novel microplastic contaminants may lead to unexpected and abrupt degradation of aquatic ecosystems, and invites systematic studies on the ecosystem-level consequences of microplastic exposure.

Microbial Succession on Microplastics in Wastewater Treatment Plants: Exploring the Complexities of Microplastic-Microbiome Interactions.

Despite some effectiveness of wastewater treatment processes, microplastics accumulate in sewage sludge and their further use may contribute to the release of plastic microplastics into the environment. There is an urgent need to reduce the amount of microplastics in sewage sludge. Plastic particles serve as solid substrates for various microorganisms, promoting the formation of microbial biofilms with different metabolic activities. The biofilm environment associated with microplastics will determine the efficiency of treatment processes, especially biological methods, and the mechanisms of organic compound conversion. A significant source of microplastics is the land application of sewage sludge from wastewater treatment plants. The detrimental impact of microplastics affects soil enzymatic activity, soil microorganisms, flora, fauna, and plant production. This review article summarizes the development of research related to microplastics and discusses the issue of microplastic introduction from sewage sludge. Given that microplastics can contain complex composite polymers and form a plastisphere, further research is needed to understand their potential environmental impact, pathogenicity, and the characteristics of biofilms in wastewater treatment systems. The article also discusses the physicochemical properties of microplastics in wastewater treatment plants and their role in biofilm formation. Then, the article explained the impact of these properties on the possibility of the formation of biofilms on their surface due to the peculiar structure of microorganisms and also characterized what factors enable the formation of specific plastisphere in wastewater treatment plants. It highlights the urgent need to understand the basic information about microplastics to assess environmental toxicity more rationally, enabling better pollution control and the development of regulatory standards to manage microplastics entering the environment.

Local and systemic effects of microplastic particles through cell damage, release of chemicals and drugs, dysbiosis, and interference with the absorption of nutrients.

Microplastic particles (MPs) have been detected in a variety of environmental samples, including soil, water, food, and air. Cellular studies and animal exposures reported that exposure to MPs composed of different polymers might result in adverse effects at the portal of entry (local) or throughout the body (systemic). The most relevant routes of particle uptake into the body are oral and respiratory exposure. This review describes the various processes that may contribute to the adverse effects of MPs. Only MPs up to 5 µm were found to cross epithelial barriers to a significant extent. However, MPs may also exert a detrimental impact on human health by acting at the epithelial barrier and within the lumen of the orogastrointestinal and respiratory tract. The potential for adverse effects on human health resulting from the leaching, sorption, and desorption of chemicals, as well as the impact of MPs on nutritional status and dysbiosis, are reviewed. In vitro models are suggested as a means of (1) assessing permeation, (2) determining adverse effects on cells of the epithelial barrier, (3) examining influence of digestive fluids on leaching, desorption, and particle properties, and (4) role of microbiota-epithelial cell interactions. The contribution of these mechanisms to human health depends upon exposure levels, which unfortunately have been estimated very differently.

Visible Combined Near-Infrared in Situ Imaging Revealed Dynamic Effects of Microplastic Fibers and Beads in Zebrafish.

Microplastics (MPs) as emerging contaminants are widely present in the environment and are ubiquitously ingested and accumulated by aquatic organisms. MPs may be quickly eliminated after a brief retention in aquatic animals (such as the digestive tract); thus, understanding the damage caused by MPs during this process and whether the damage can be recovered is important. Here, we proposed the use of visible light imaging to track MPs combined with near-infrared (NIR) imaging to reveal the in situ impacts of MPs. The combination of these two techniques allows for the simultaneous investigation of the localization and functionality of MPs in vivo. We investigated the effects of two types of MPs on zebrafish, microplastic fibers (MFs) and microplastic beads (MBs). The results showed that MPs larger than 10 µm primarily accumulated in the intestines of zebrafish. Both MFs and MBs disrupted the redox balance of the intestine, and the location of the damage was consistent with the heterogeneous accumulation of MPs. MFs caused greater and more difficult-to-recover damage compared to MBs, which was closely related to the slower elimination rate of MFs. Our study highlights the importance of capturing the dynamic toxicological effects of MPs on organisms. Fibrous MPs and spherical MPs clearly had distinct effects on their toxicokinetics and toxicodynamics in fish.

Transport and Accumulation of Microplastics from Biosolids to Australian Agricultural Soils: Detection of Microplastics Down to 1 µm.

The shift toward sustainable agriculture involves replacing inorganic fertilizers with organic alternatives like biosolids. However, concerns arise over emerging contaminants, such as microplastics (MPs), which remain largely unregulated. Despite their common use in Australia, the transfer of MPs from biosolids to agricultural soils remains largely unknown. Herein, we have investigated the abundance, characteristics, and transport of MPs resulting from biosolids application in two Queensland agricultural sites. MP concentrations were significantly higher in biosolid-amended soils (average of 1137 MPs/kg) than in reference sites (average of 36 MPs/kg), correlating with the volume, time since application, and frequency of biosolids application. MPs > 25 µm were predominantly polyethylene, polypropylene, and poly(methyl methacrylate) fragments (up to 85%). Fibers constitute only 15-30% of MPs and mainly in larger sizes (average 1011 µm), whereas fragments (average 188 µm) and beads (average 72 µm) had smaller size ranges. Despite analytical challenges using Raman spectroscopy, detected smaller MPs (1-25 µm) were fragments composed of polyethylene, polypropylene, and poly(vinyl alcohol). This study provides the first report of MPs down to 1 µm in Australian agricultural soils. Our findings suggest a need to assess the long-term impact of MPs in biosolids on soil health and food safety. We call on policymakers to consider the implementation of effective MP source control strategies and the development of guidelines for acceptable biosolids application rates.

Real-Time Visualization of Infiltration and Retention of Microplastics with Different Shapes in Porous Media.

Infiltration and retention of microplastics in porous media are important for understanding their fate in environments and formulating treatment measures. Given porous media opacity, knowledge is usually obtained indirectly by monitoring microplastic concentration in the effluent and measuring microplastic distribution after removing grains in layers. In this study, real-time visualization of infiltration and retention of microplastics in porous media under vertical water flow is performed using an improved reflective index matching method, considering the different shapes and densities of microplastics and size ratios between microplastics and grains. The spherical microplastics have the largest infiltration depths, with trajectories closest to vertical and accompanied by long acceleration durations and low deceleration frequencies. The cylindrical microplastics deviate from vertical and have stronger transverse oscillations and more frequent decelerations, while the flaky microplastics have the most significant transverse displacements. The infiltration depth can be improved by reducing the size ratio between microplastics and grains and increasing the vertical flow rate, while the density of microplastics has a relatively limited effect. Sliding and rotating of microplastics after collision with grains are observed, responsible for deceleration and transverse displacements. Different retention patterns are found, with the number of types being inversely proportional to the number of principal dimensions of the shape.

Network Complexity and Stability of Microbes Enhanced by Microplastic Diversity.

Microplastic mixtures are ubiquitously distributed in global ecosystems and include varying types. However, it remains unknown how microplastic diversity affects the biotic interactions of microbes. Here, we developed novel experiments of 600 microcosms with microplastic diversity ranging from 1 to 6 types and examined ecological networks for microbial communities in lake sediments after 2 months of incubation at 15 and 20 °C. We found that microplastic diversity generally enhanced the complexity of microbial networks at both temperatures, such as increasing network connectance and reducing average path length. This phenomenon was further confirmed by strengthened species interactions toward high microplastic diversity except for the negative interactions at 15 °C. Interestingly, increasing temperatures further exaggerated the effects of microplastic diversity on network structures, resulting in higher network connectivity and species interactions. Consistently, using species extinction simulations, we found that higher microplastic diversity and temperature led to more robust networks, and their effects were additionally and positively mediated by the presence of biodegradable microplastics. Our findings provide the first evidence that increasing microplastic diversity could unexpectedly promote the complexity and stability of microbial networks and that future warming could amplify this effect.

Mapping Microplastic Movement: A Phase Diagram to Predict Nonbuoyant Microplastic Modes of Transport at the Particle Scale.

Microplastics pose numerous threats to aquatic environments, yet understanding their transport mechanisms remains limited. Drawing from natural sediment research provides valuable insights to address this knowledge gap. One key dimensionless number used to describe sediment transport is the transport stage, referring to the ratio between the flow shear velocity and the particle settling velocity. However, variations in physical properties, such as shape and density, raise concerns about the applicability of existing sediment transport theories to microplastics. To address this challenge, we employed a physical modeling approach, examining 24 different nonbuoyant microplastic particles in a turbulent open channel flow. Utilizing 3D particle tracking, a total of 720 trajectories were recorded and analyzed. Microplastic particles exhibited transport modes akin to natural sediments, including rolling/sliding, saltation, and suspension. The transport stage strongly correlated with these modes, as well as with the mean forward velocity and mean position in the water column. Notably, particle shape emerged as a critical factor influencing transport dynamics. Due to their lower settling velocity, fibers tended to stay closer to the water surface with lower forward velocities compared to spheres. Based on the laboratory results, a new phase diagram for microplastics is introduced analogous to an existing diagram for sediments.

Microplastic Human Dietary Uptake from 1990 to 2018 Grew across 109 Major Developing and Industrialized Countries but Can Be Halved by Plastic Debris Removal.

Microplastics (MPs), plastic particles smaller than 5 mm, are now a growing environmental and public health issue, as they are detected pervasively in freshwater and marine environments, ingested by organisms, and then enter the human body. Industrial development drives this environmental burden caused by MP formation and human uptake by elevating plastic pollution levels and shaping the domestic dietary structure. We map the MP human uptake across 109 global countries on five continents from 1990 to 2018, focusing on the world's major coastlines that are affected by plastic pollution that affects the United Nations' Sustainable Development Goals (SDGs): SDG 6 (Clean Water and Sanitation), SDG 14 (Life Below Water), and SDG 15 (Life on Land). Amid rapid industrial growth, Indonesia tops the global per capita MP dietary intake at 15 g monthly. In Asian, African, and American countries, including China and the United States, airborne and dietary MP uptake increased over 6-fold from 1990 to 2018. Eradicating 90% of global aquatic plastic debris can help decrease MP uptake by more than 48% in Southeast Asian countries that peak MP uptake. To reduce MP uptake and potential public health risks, governments in developing and industrialized countries in Asia, Europe, Africa, and North and South America should incentivize the removal of free plastic debris from freshwater and saltwater environments through advanced water treatment and effective solid waste management practices.

Modeling of Microplastics Migration in Soil and Groundwater: Insights into Dispersion and Particle Property Effects.

Migration of microplastics (MPs) in soil-groundwater systems plays a pivotal role in determining its concentration in aquifers and future threats to the terrestrial environment, including human health. However, existing models employing an advection-dispersion equation are insufficient to incorporate the holistic mechanism of MP migration. Therefore, to bridge the gap associated with MP migration in soil-groundwater systems, a dispersion-drag force coupled model incorporating a drag force on MPs along with dispersion is developed and validated through existing laboratory and field-scale experiments. The inclusion of the MP dispersion notably increased the global maximum particle velocity (vmaxp) of MPs, resulting in a higher concentration of MPs in the aquifer, which is also established by sensitivity analysis of MP dispersion. Additionally, increasing irrigation flux and irrigation areas significantly accelerates MP migration downward from soil to deep saturated aquifers. Intriguingly, vmaxp of MPs exhibited a nonlinear relationship with MPs' sizes smaller than 20 µm reaching the highest value (=1.64 × 10-5 m/s) at a particle size of 8 µm, while a decreasing trend was identified for particle sizes ranging from 20 to 100 µm because of the hindered effect by porous media and the weaker effect of the drag force. Moreover, distinct behaviors were observed among different plastic types, with poly(vinyl chloride), characterized by the highest density, displaying the lowest vmaxp and minimal flux entering groundwater. Furthermore, the presence of a heterogeneous structure with lower hydraulic conductivity facilitated MP dispersion and promoted their migration in saturated aquifers. The findings shed light on effective strategies to mitigate the impact of MPs in aquifers, contributing valuable insights to the broader scientific fraternity.

Rapid Generation of Microplastics and Plastic-Derived Dissolved Organic Matter from Food Packaging Films under Simulated Aging Conditions.

In this study, we show that low-density polyethylene films, a prevalent choice for food packaging in everyday life, generated high numbers of microplastics (MPs) and hundreds to thousands of plastic-derived dissolved organic matter (DOM) substances under simulated food preparation and storage conditions. Specifically, the plastic film generated 66-2034 MPs/cm2 (size range 10-5000 µm) under simulated aging conditions involving microwave irradiation, heating, steaming, UV irradiation, refrigeration, freezing, and freeze-thaw cycling alongside contact with water, which were 15-453 times that of the control (plastic film immersed in water without aging). We also noticed a substantial release of plastic-derived DOM. Using ultrahigh-resolution mass spectrometry, we identified 321-1414 analytes with molecular weights ranging from 200 to 800 Da, representing plastic-derived DOM containing C, H, and O. The DOM substances included both degradation products of polyethylene (including oxidized forms of oligomers) and toxic plastic additives. Interestingly, although no apparent oxidation was observed for the plastic film under aging conditions, plastic-derived DOM was more oxidized (average O/C increased by 27-46%) following aging with a higher state of carbon saturation and higher polarity. These findings highlight the future need to assess risks associated with MP and DOM release from plastic wraps.