Effects of aging on environmental behavior of plastic additives: Migration, leaching, and ecotoxicity

Core-shell molecularly imprinted polymers for the monitoring of dimethyl phthalate in the children's toys1

Plastic materials contain many additives, among which plasticizers from the group of phthalates are added during the production of everyday products, including children's toys. Even if the European Union and many other regions, for example Canada and the United States, have established restrictions on phthalate esters in children's toys or food contact materials and electronic and electrical products, there is still a danger that products imported from regions where there are no such restrictions can contain these dangerous compounds belonging to the group of endocrine disruptors. The additives introduced into plastics are not chemically bound to the polymer chain, so they can easily migrate to the external environment. This paper presents the process of synthesis of the core-shell type of molecularly imprinted polymers (MIPs) toward dimethyl phthalate (DMP). The most suitable polymerization mixture, which was selected to obtain the MIP layer, was prepared from the 4:6 wt ratio of methyl methacrylate and ethylene glycol dimethacrylate in the n-octane environment and with the addition of 5 wt% of the template. This material was characterized with the highest value of DMP removal, the maximum sorption capacity of this thin layer of MIP was about 3.0 mg/L. Additionally, DMP was about 3 times and about 5 times more efficient sorbed by core-shell MIP, than diethyl phthalate (DEP) and dibutyl phthalate (DBP), respectively. The best sorbed core-shell molecularly imprinted polymer was used as a column filler for solid phase extraction and was used to identify the phthalates present from rubber duck extraction solutions, showing the presence of this compound in the analyzed samples. The method developed in this work has a low limit of detection (LOD) and a low limit of quantification (LOQ) and a wide linear range, allowing DMP to be determined at both at trace levels (0.151 mg/L) and at higher concentrations.

Metal leaching accompanied with natural photo-aging behavior of e-waste plastic derived microplastics in aquatic environment

As the main component of electronic products, plastics contain complex and diverse metal additives. Recycling process is not conducive to stable existence of metal additives in electronic plastics. Once the e-waste plastics enter the environment, they will continue to release harmful metals into environment after aging, causing serious hazards. This study delved into the analysis and comparison of metal content of e-waste plastics, elucidating aging process and metal leaching behavior over a 112-day natural light exposure period. The findings underscored that metal content in recycled plastics surpassed that in their new counterparts. Specifically, Ti content in new plastics remained below 100 mg/kg, while recycled plastics exhibited Ti content surpassing 100 mg/kg threshold. Throughout prolonged natural light exposure, metals such as Zn, Ba and Sb demonstrated a heightened likelihood of release from electronic plastics in comparison to other metals. The aging process during light exposure led to fragmentation of electronic plastics, accompanied by a reduction in particle size. Notably, the particle size reduction was more pronounced in poly acrylonitrile butadiene styrene (ABS) and recycled ABS, experiencing reductions of 40 µm and 85 µm, respectively. This phenomenon was attributed to the presence of polybutadiene structural units, which proved more susceptible to aging. Along with the breaking of plastics, the ABS plastics released metal species such as Pb, Cd, Ni, Al that had not been detected in other plastics solutions. The collective evidence from this study suggested that ABS and recycled ABS electronic plastics might pose a heightened potential environmental risk compared to other electronic plastics.

Recent advances in occurrence, biotreatment, and integrated insights into bacterial degradation of phthalic acid esters in aquatic environments

Phthalic acid esters (PAEs) are prevalent as emerging contaminants owing to their widespread use as plasticizers in industry. Despite their environmental and health risks, a limited understanding of PAE contamination in aquatic environments hinders the practical implementation of biotreatment strategies for their removal. This paper reviews the advances in occurrence, biotreatment, and relevant integrative analysis of bacterial PAE degradation over the past decade. In various aquatic environments, dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) are the predominant PAE pollutants across different regions, with alarming levels reported in Eastern China. PAEs in water usually inhibit the growth and metabolism of surrounding organisms. Meanwhile, various biotreatment techniques have proven effective in removing PAEs from leachate and wastewater. The treatment efficiency can be further enhanced by incorporating suitable physicochemical processes and optimizing key factors, such as the initial pollutant concentration, PAE type, and reaction time. Additionally, a K-means machine learning algorithm and 16S rRNA gene-based evolutionary analysis were employed to reveal that soil is a preferred source for isolating strains, with Gordonia and Pseudomonas being the dominant genera of PAE-degrading bacteria exhibiting high degradation efficiency. Moreover, most PAE hydrolase genes were discovered in these two genera. Different gene clusters facilitated the subsequent degradation pathways under aerobic or anaerobic conditions. This paper presents the latest updates on PAE biotreatment and offers an integrated analysis of the bacterial degradation involved. Future research should apply these insights to enhance the overall effectiveness of PAE removal in water.

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.

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.

Flexible natural deep eutectic solvent extraction coupled with precolumn-switching HPLC-FLD to analyze fluorescent whitening agents in diverse sample matrices for migration study

This study proposes a novel analytical approach coupling of natural deep eutectic solvent (NADES) extraction with a precolumn-switching high-performance liquid chromatography with fluorescence detection (HPLC-FLD) system for analyzing fluorescent whitening agents (FWAs) in diverse sample matrices. NADES (coumarin/thymol) provide a green alternative to conventional solvents. The automated precolumn-switching strategy overcomes the compatibility issues between DES and HPLC, preventing column contamination and maintaining separation efficiency without the need for extensive dilution of NADES prior to injection. Three NADES extraction modes were proposed: phase-reversed NADES liquid-liquid extraction, NADES liquid-solid extraction, and NADES dispersive liquid-liquid microextraction, to achieve effective FWAs analysis in blood, urine, packaging materials, cosmetics, and cosmetic simulants. Method validation shows high sensitivity, with limits of detection (LODs) as low as 0.002 μg/L and good accuracy (recoveries 88.2 %-114.4 %). The practicality and reliability of this method are confirmed through its application to real positive samples from various source. Additionally, the research investigates FWAs migration from packaging to cosmetics and simulants, which also reveals the FWAs migration from sanitary products into blood and urine for the first time. The Weibull model has been proven to effectively describe FWAs migration behavior and provides a predictive tool for long-term migration risk assessment. This work not only provides a novel, green analytical approach for FWAs but also contributes valuable data for evaluating the safety of cosmetic packaging and sanitary products.

Leaching-driven transformations of tire wear particles (TWPs): Uncovering the neglected environmental implications

Extensive research has been conducted on the leaching behavior and risks of the leachate of tire wear particles (TWPs) in aquatic environments. However, the leaching-driven transformations of TWPs and the subsequent environmental impacts have been largely overlooked. This work examines the changes in physicochemical properties of TWPs during leaching in several water bodies, thereby facilitating a more thorough assessment of the environmental impacts. The results revealed that the environmental behavior related properties of TWPs, including surface morphology, pores, contact angel, zeta potential, functional groups, and surface adsorption sites varied at different levels during leaching. The ionic strength and organic matter content of water body highly determine the above transformations. The carbon index (CI) and O/C ratio of TWPs increased by 55.40 % and 14.27 % after leached in the water for 30 days, while the adsorption capacity of the TWPs for tetracycline (TC) and oxytetracycline (OTC) decreased by 27 % and 24.63 %, respectively. Herein, the changes in the functional groups and polarity during leaching highly influenced the adsorption performance of leached-TWPs. This study provides novel insight into understanding the leaching behavior of TWPs in aquatic environments and highlights an urgent need to assess the environmental implications of leaching-driven transformations of TWPs.

Release mechanisms of decabromodiphenyl ether from typical e-waste microplastics into water: Insights from molecular dynamics simulations

E-waste-derived microplastics (MPs) serve as a significant source, have been releasing decabromodiphenyl ether (BDE-209) into aquatic environment. Conventional release kinetics experiments fail to effectively distinguish the three-stage release process, which includes internal diffusion, interfacial mass transfer, and diffusion in the environment. Herein, we took typical flame-retardant plastic (polystyrene, PS) as a paradigm to construct diffusion and release models corresponding to the three-stage release process, with large-scale all-atom molecular dynamics (MD) simulations providing insights into the release process. The level of BDE-209's self-diffusion coefficients (D) was calculated at different release stages: 10-14 (PS matrix), 10-12 (PS-water interface), and 10-10 m2 s-1 (bulk water). BDE-209 exhibits a confined diffusion mode within the PS matrix, significantly diminishing its release capability. At the interface, the strength of dispersion attraction between BDE-209 and the PS surface determines the ease of its release and the partition equilibrium between the two phases. Our findings elucidated the molecular-scale dynamic and thermodynamic mechanisms governing BDE-209 release from MPs into water, expanding the understanding of polybrominated diphenyl ether release from e-waste-derived MPs. Moreover, our established MD simulation methods can be adapted to explore the release or adsorption mechanisms of various additives in different kinds of MPs.

Microplastic contamination in green mussels (Perna viridis Linnaeus, 1858) from traditional seafood markets in Jakarta, Indonesia, and an evaluation of potential hazards

Marine organisms, especially mussels, can efficiently take up microplastics (MPs) through their filtration processes. This study evaluated the characteristics of MPs in green mussels (Perna viridis) sold at traditional seafood markets in Jakarta, Indonesia. The polymers of MPs were examined using Fourier Transform Infrared spectroscopy, while the chemical components of MPs in green mussels were analyzed using Gas Chromatography-Mass Spectrometry. The MPs identified in green mussels sold at traditional seafood markets in Jakarta are predominantly of fiber type, display a black coloration, and measure <100 μm in size. The density of these microplastics in green mussels is uniform across all traditional markets. The concentration of microplastics in green mussels correlates positively with the length of the green mussel shell. The average annual consumption of mussel products by people in Jakarta was 11,170 items/year/person. Green mussels from Jakarta exhibited a significantly elevated polymer hazard index (III), indicating the presence of polymers categorized as high risk. Certain plasticizers (phthalates) and specific additive chemicals (phenol, butylated hydroxytoluene, and hexadecanamide) were also present in green mussels sourced from traditional markets in Jakarta. These substances are toxic and have a negative impact on both aquatic life and humans.

Migration of chemical substances from packaging materials to food

At present, active food packaging is favored by manufacturers and consumers from all over the world for various special functions. However, the potential migration of chemical substances from the packaging into the food during contact is a significant concern. Therefore, a detailed discussion of this topic is warranted. This paper begins with a thorough analysis of the migration mechanisms, mathematical models, and critical parameters involved in the migration of chemical substances from food packaging. On this basis, it summarizes relevant detection techniques, the selection of food simulants, and risk assessment, which are crucial for the accuracy of migration test results. In addition, specific attention was focused on the migration of antimicrobial agents in food packaging. Finally, non-destructive testing methods, international legislation, and current opportunities and challenges were discussed. The research provides important guidance and inspiration for investigating the migration of chemical substances from food packaging to food.

Ecological and Health Risk Mediated by Micro(nano)plastics Aging Process: Perspectives and Challenges

Aged micro(nano)plastics (MNPs) are normally the ultimate state of plastics in the environment after aging. The changes in the physical and chemical characteristics of aged MNPs significantly influence their environmental behavior by releasing additives, forming byproducts, and adsorbing contaminants. However, a systematic review is lacking on the effects of aged MNPs on ecological and human health regarding the increasing but scattered studies and results. This Review first summarizes the unique characteristics of aged MNPs and methods for quantifying their aging degree. Then we focused on the potential impacts on organisms, ecosystems, and human health, including the "Trojan horse" under real environmental conditions. Through combining meta-analysis and analytic hierarchy process (AHP) model, we demonstrated that, compared to virgin MNPs, aged MNPs would result in biomass decrease and oxidative stress increase on organisms and lead to total N/P decrease and greenhouse gas emissions increase on ecosystems while causing cell apoptosis, antioxidant system reaction, and inflammation in human health. Within the framework of ecological and human health risk assessment, we used the risk quotient (RQ) and physiologically based pharmacokinetic (PBK) models as examples to illustrate the importance of considering aging characteristics and the degree of MNPs in the process of data acquisition, model building, and formula evaluation. Given the ecological and health risks of aged MNPs, our urgent call for more studies of aged MNPs is to understand the potential hazards of MNPs in real-world environments.

Bringing to light vinyl chloride oligomers, a class of polychlorinated alkanes differing from chlorinated paraffins

Polyvinyl chloride (PVC) is one of the most widely used polymers, which contrasts with the low amount of literature on the leaching of associated additives and in particular unintended oligomers, a class of non-intentionally added substances (NIAS). This study sheds light on the occurrence of vinyl chloride oligomers (VCOs) in a variety of PVC analytical standards (n = 4), PVC items employed for construction, medical or food contact applications (n = 14), as well as in foodstuffs and environmental matrices (n = 10). Samples were analysed by liquid chromatography coupled to high-resolution mass spectrometry hyphenated with chloride-enhanced electrospray ionisation. Series of saturated (0VCO), monounsaturated (1VCO), diunsaturated (2VCO) and triunsaturated (3VCO) VCOs were revealed. The dominant series remained 1VCOs of the general formula C2nH3nCln, accounting for ∼80 % of VCOs in PVC standards. A risk of signal overlap was found between 0VCOs of the general formula C2nH3n+1Cln+1 (accounting for ∼8 % in PVC standards) and polychlorinated alkanes making up chlorinated paraffins, given that they share the same chemical formulas. A methodology for discriminating between signals arising from VCOs and chlorinated paraffins has been proposed. VCOs were detected in 88 % of the samples analysed (other than standards), and in particular in some foodstuffs and environmental matrices, suggesting that VCOs have the capacity to leach out of PVC materials, and thus contaminate food and the environment. Overall, these results call for greater attention to be paid to vinyl chloride oligomers and raise the question of whether they pose a risk to living organisms.

Coding and non-coding transcripts modulated by transparent and blue PET micro-nanoplastics in Arabidopsis thaliana

To get further insights on the micro-nanoplastic (MNP) effects on plants, the aim of this study was to evaluate the response of hydroponically cultivated Arabidopsis thaliana to the presence of differentially colored polyethylene terephthalate (PET) particles. MNP impacts on the root organ were studied at a molecular level, with a special focus on the role of long non-coding RNAs (lncRNAS) in the regulation of gene expression after PET exposure. MNPs of transparent (Tr-PET) and blue (Bl-PET) material at environmentally realistic concentration caused a significant reduction in root length, while only Bl-PET significantly reduced rosette area. MNPs induced oxidative stress markers. Tr-PET upregulated genes involved in signaling of xenobiotics, whereas Bl-PET scarcely affected root transcriptomic profile, activating few gene categories for abiotic stresses. Regarding hormones, genes involved in ABA response were repressed, while brassinosteroid-related genes were differentially regulated by Tr-PET. Both MNPs, but especially Tr-PET, upregulated major latex protein-related genes. Plant molecular response to MNPs was linked to differential abundance of lncRNAs on both comparisons. Tr-PET affected the expression of much more lncRNAs than bl-PET (80 and 11 respectively). These lncRNAs were predicted to interact with several repressed protein-coding genes (i.e. glucosyltransferase UGT2, oxidative stress genes etc.), with possible effects on their regulation. A lncRNA (AT1G09297) interacted with CYP81D8, a key gene of cytochrome P450 gene family involved in xenobiotics detoxification. Two lncRNAs interacted with two members of repressed HSP (HSP90 and HSP17.4) family. Finally, genes involved in redox detoxification and stress responses were inhibited by the interaction with two microplastics-regulated lncRNAs. These data highlighted the need of investigating non-coding RNAs in the future in addition to the mostly studied protein coding transcriptome.

Antimony release from e-waste-derived microplastics in aqueous environments: Effect of plastic properties and environmental factors

Antimony (Sb) is an emerging contaminant widely concerned by researchers recently. Sb2O3, the flame-retardant synergist extensively used in plastics for electronic products, is an important source of Sb pollution. It can be released into the environment from e-waste, especially from the formed microplastics (MPs). However, the behavior and mechanisms of Sb release remain unclear. This study investigated the release behavior of Sb from two typical e-waste-derived MPs, acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS). The effects of particle size, plastic aging, and environmental conditions (pH, humic acid, and inorganic ions) on Sb release were explored. It was found that HIPS exhibited higher total Sb (Sbtot) release than ABS, due to differences in their hydrophilicity and crystallinity. When the particle size was reduced from 2 mm to 0.15 mm, Sbtot release from HIPS and ABS increased by 620% and 350%. UV aging increased hydrophilicity and decreased crystallinity of MPs, further enhancing Sbtot release. Notably, there were about 40% Sb(III) in Sbtot released by pristine MPs, whereas in the leachate from the UV-aged MPs, Sbtot was exclusively Sb(V). Sbtot release was greatly enhanced by acidic and alkaline environments, especially at extreme pH levels, while humic acid has an inhibitory effect on the Sbtot release. These results suggest considerable amounts of Sb can be released into the environment from e-waste-derived MPs, and affected by various environmental factors. These findings improve understanding of Sb release from MPs in e-waste areas under various environmental conditions, providing insights into environmental risks tied to additive release from MPs.

Impacts of climatic stressors on dissolved organic matter leaching from microplastics and their effects on biogeochemical processes: A review

This review explores the potential impact of microplastic-derived dissolved organic matter (MP-DOM) on biogeochemical processes associated with global carbon and nitrogen cycles, with consideration given to the possible influence of irregular climate changes. We synthesize literature on MP-DOM leaching behaviors during various natural aging processes, such as heavy rainfall, heat waves, and UV irradiation, which may be intensified by climate change. MP-DOM release varies with plastic type and conditions, with organic additives significantly influencing leaching under UV exposure. Increased turbulence from hydrological events and rising temperatures also enhances MP-DOM release. While most research has focused on specific additive releases, the broader effects of polymer degradation and subsequent impacts on microbial communities and biogeochemical cycles are only recently recognized. These disruptions may affect cellular processes in algae and plant roots, enhance microbial utilization of dissolved organic carbon, and potentially increase greenhouse gas production. Our review highlights overlooked roles of MP-DOM exacerbated by climatic stressors and calls for further research to understand its broader biogeochemical impacts. We also emphasize the importance of distinguishing between polymers and commercial plastics when assessing MP-DOM's effects on biogeochemical processes associated with carbon and nitrogen cycles and recommend investigating additional aging processes influencing MP-DOM release.

Assessing ecotoxicity of plastic additives to apply in effect factors for Life Cycle Impact Assessment

Plastic waste poses a significant environmental challenge, drawing considerable research, media, and policy attention primarily focused on its visible impact. The plastic industry incorporates various additives, such as plasticisers, to achieve desired product properties. Consequently, plastics are potential vectors for the release of these additives into the aquatic environment, posing ecotoxicological risks. Despite the prevalence of these additives in aquatic ecosystems, there are substantial knowledge gaps concerning their ecotoxicological effects, especially in the context of Life Cycle Impact Assessment (LCIA). There is a lack of characterization models for additives to assess their environmental impact on the plastic life cycle. This study aims to address this gap by providing aquatic ecotoxicity data aiming to calculate EF specifically for plastic packaging additives. We conducted a battery of ecotoxicological tests involving species from three trophic levels, to estimate effects such as growth inhibition of algae Raphidocelis subcapitata, acute immobilisation of invertebrate Daphnia magna, as well as the toxicity assessment of the luminescent bacteria Aliivibrio fischeri following OECD guidelines and the requirements to produce relevant data for LCIA advances. These data are crucial for a better understanding of the environmental impact of plastic additives on aquatic ecosystems, contributing to LCIA by refining and expanding the available sets of effect factors. Advancements in this area enhance plastic life cycle assessment, enabling the identification of toxicity associated with additives and the estimation of their chemical footprint. The findings of this study not only expand the number of effect factors available for additives used in plastic packaging but also support initiatives aiming to minimize environmental hazards associated with plastic waste. This knowledge should also inform sustainable practices in plastic production.

Uncovering layer by layer the risk of nanoplastics to the environment and human health

Nanoplastics (NPs), defined as plastic particles with dimensions less than 100 nm, have emerged as a persistent environmental contaminant with potential risk to both environment and human health. Nanoplastics might translocate across biological barriers and accumulate in vital organs, leading to inflammatory responses, oxidative stress, and genotoxicity, already reported in several organisms. Disruptions to cellular functions, hormonal balance, and immune responses were also linked to NPs exposure in in vitro assays. Further, NPs have been found to adsorb other pollutants, such as persistent organic pollutants (POPs), and leach additives potentially amplifying their advere impacts, increasing the threat to organisms greater than NPs alone. However, NPs toxic effects remain largely unexplored, requiring further research to elucidate potential risks to human health, especially their accumulation, degradation, migration, interactions with the biological systems and long-term consequences of chronic exposure to these compounds. This review provides an overview of the current state-of-art regarding NPs interactions with environmental pollutants and with biological mechanisms and toxicity within cells.

Towards harmonized ecotoxicological effect assessment of micro- and nanoplastics in aquatic systems

Micro- and nanoplastics are globally important environmental pollutants. Although research in this field is continuously improving, there are a number of uncertainties, inconsistencies and methodological challenges in the effect assessment of micro- and nanoparticles in freshwater systems. The current understanding of adverse effects is partly biased by the use of non-relevant particle types, unsuitable test setups and environmentally unrealistic dose metrics, which does not take into account realistic processes in particle uptake and consequent effects. Here we summarize the current state of the art by compiling the most recent research with the aim to highlight research gaps and further necessary steps towards more harmonized testing systems. In particular, ecotoxicological scenarios need to mirror environmentally realistic particle diversity and bioavailability. Harmonized test setups should include different uptake pathways, exposures and comparisons with natural reference particles. Effect assessments need to differentiate direct physical particle effects, such as lesions and toxicity caused by the polymer, from indirect effects, such as alterations of ambient environmental conditions by leaching, change of turbidity, food dilution and organisms' behavior. Implementation of these suggestions can contribute to harmonization and more effective, evidence-based assessments of the ecotoxicological effects of micro- and nanoplastics.

Occurrence and migration of synthetic phenolic antioxidants in food packaging materials: Effects of plastic types and storage temperature

Synthetic phenolic antioxidants (SPAs) are widely used in food packaging materials to extend product shelf life. Not much attention has been paid to high molecular weight SPAs (HMW SPAs) so far, despite their potential health risks. In this study, we first analyzed the concentrations of ten HMW SPAs in food plastic packaging materials (including 6 plastic categories, n = 116). The total concentrations of HMW SPAs (∑SPAs) ranged from 0.0844 to 894 mg/kg, with a geometric mean of 71.7 mg/kg. The predominant HMW SPAs included AO1010 (accounting for 71.8 % of total concentrations of HMW SPAs), AO1076 (21.4 %), and AO3114 (3.14 %), with AO1010 detected in all samples. Higher concentrations were notably found in polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) materials. Migration tests revealed that HMW SPAs could readily transfer into food simulants, with PP exhibiting the lowest migration levels. Migration of SPAs into fatty foods was pronounced, increasing with temperature (temperature gradients: 4 °C, 25 °C, and 60 °C). In the 95 % ethanol food simulants, the maximum migration amounts of AO1076 in PE (7.05 mg/kg at 25 °C) and PET (9.79 mg/kg at 25 °C; 10.8 mg/kg at 60 °C) surpassed the specific migration limit (SML) set by the national standards, posing potential food safety risks. This was the first report on the presence and migration patterns of ten HMW SPAs in food plastic packaging materials, providing crucial insights into food packaging material safety.

Exposure to leachates of plastic food containers disturbs glucose and lipid metabolism: Insights from models mimicking real-exposure scenarios

The increasing use of plastic food containers, particularly for pre-cooked meals and takeout services, has raised concerns regarding the potential health risks associated with plastic leachates. This study investigated the impact of leachates from heat-treated polypropylene (PP) plastic food containers on glucose and lipid metabolism using both in vitro and in vivo models. AML12 hepatocytes exposed to leachates from three different PP plastic containers exhibited significant disruptions in the homeostasis of lipid and glucose metabolism, evidenced by increased intracellular lipid content and altered gene expression related to lipogenesis, lipid uptake, lipolysis, and fatty acid β-oxidation. C57BL/6J mice were fed with the mouse diet that had been heated in two distinct types of PP plastic food containers for 8 weeks and these mice exhibited accelerated body weight gain, altered fasting blood glucose levels, and changes in serum lipid profiles. Histological analysis revealed increased adipocyte size, liver steatosis, and glycogen accumulation. Transcriptome sequencing of liver tissues highlighted significant alterations in the expression of genes involved in metabolic pathways, further corroborated by real-time qPCR validation. These findings underscore the potential metabolic health risks posed by the use of heated plastic food containers.

Forensic determination of adhesive vinyl microplastics in urban soils

Plastic production and consumption hubs are mainly concentrated in urban centers, causing the soil in these places to become sinks of plastic fragments. Adhesive vinyl polymers are widely used in various commercial sectors and, to the best of our knowledge, this is the first study to investigate the potential for this type of material to form microplastics in urban soils. This proof-of-concept work started by studying the soil around a sign made of adhesive vinyl that had been exposed to the weather for eight years and showed evident signs of degradation, like cracking and color fading. We separated the microplastics with a two-step density separation protocol and selected only the microplastics targeted by this research, finding up to 5,570 fragments produced from 1 cm2 of adhesive vinyl film. In the soil below the sign, we registered 5.6 × 104 fragments kg-1 of dry soil on its topsoil layer (0-10 cm), 1.2 × 104 fragments kg-1 in the 10-20 cm layer, and 1 × 104 fragments kg-1 in the 20-30 layer. At a distance of 1 and 2 m from the sign, the highest concentration of fragments was also in the topsoil, respectively 9.3 × 103 and 5.3 × 102 fragments kg-1. We also observed that vertical and horizontal transport was not favored, causing the formation of hotspots near the source and that the area of the fragments did not influence vertical transport. Another important finding regarding the characterization technique is that degraded polyvinyl chloride is unlikely to be identified through FTIR without comparison to the source. Here, we presented a low-cost forensic assessment of the association between the presence of MPs and its source that can be used both for the development of public policies and for setting up quality controls for polluting companies.The results here presented reveal the need to rethink the use and types of materials used for visual identities and signage in urban environments.

Machine Learning-Assisted "Shrink-Restricted" SERS Strategy for Classification of Environmental Nanoplastic-Induced Cell Death

The biotoxicity of nanoplastics (NPs), especially from environmental sources, and "NPs carrier effect" are in the early stages of research. This study presents a machine learning-assisted "shrink-restricted" SERS strategy (SRSS) to monitor molecular changes in the cellular secretome exposure to six types of NPs. Utilizing three-dimensional (3D) Ag@hydrogel-based SRSS, active targeting of molecules within adjustable nanogaps was achieved to track information. Machine learning was employed to analyze the overall spectral profiles, biochemical signatures, and time-dependent changes. Results indicate that environmentally derived NPs exhibited higher toxicity to BEAS-2B and L02 cells. Notably, the "NPs carrier effect," resulting from pollutant adsorption, proved to be more harmful. This effect altered the death pathway of BEAS-2B cells from a combination of apoptosis and ferroptosis to primarily ferroptosis. Furthermore, L02 cells demonstrated greater metabolic vulnerability to NPs exposure than that of BEAS-2B cells, especially concerning the "NPs carrier effect." Traditional detection methods for cell death often rely on end point assays, which limit temporal resolution and focus on single or multiple markers. In contrast, our study pioneers a machine learning-assisted SERS approach for monitoring overall metabolic levels post-NPs exposure at both cellular and molecular levels. This endeavor has significantly advanced our understanding of the risks associated with plastic pollution.

Plastic additives as a new threat to the global environment: Research status, remediation strategies and perspectives

Discharge or leaching of plastic additives, which are an essential part of the plastic production process, can lead to environmental pollution with serious impacts on human and ecosystem health. Recently, the emission of plastic additives is increasing dramatically, but its pollution condition has not received enough attention. Meanwhile, the effective treatment strategy of plastic additive pollution is lack of systematic introduction. Therefore, it is crucial to analyze the harm and pollution status of plastic additives and explore effective pollution control strategies. This paper reviews the latest research progress on additives in plastics, describes the effects of their migration into packaged products and leaching into the environment, presents the hazards of four major classes of plastic additives (i.e., plasticizers, flame retardants, stabilizers, and antimicrobials), summarizes the existing abiotic/biotic strategies for accelerated the remediation of additives, and finally provides perspectives on future research on the removal of plastic additives. To the best of our knowledge, this is the first review that systematically analyzes strategies for the treatment of plastic additives. The study of these strategies could (i) provide feasible, cost-effective abiotic method for the removal of plastic additives, (ii) further enrich the current knowledge on plastic additive bioremediation, and (iii) present application and future development of plants, invertebrates and machine learning in plastic additive remediation.

Microplastics as an Emerging Potential Threat: Toxicity, Life Cycle Assessment, and Management

The pervasiveness of microplastics (MPs) in terrestrial and aquatic ecosystems has become a significant environmental concern in recent years. Because of their slow rate of disposal, MPs are ubiquitous in the environment. As a consequence of indiscriminate use, landfill deposits, and inadequate recycling methods, MP production and environmental accumulation are expanding at an alarming rate, resulting in a range of economic, social, and environmental repercussions. Aquatic organisms, including fish and various crustaceans, consume MPs, which are ultimately consumed by humans at the tertiary level of the food chain. Blocking the digestive tracts, disrupting digestive behavior, and ultimately reducing the reproductive growth of entire living organisms are all consequences of this phenomenon. In order to assess the potential environmental impacts and the resources required for the life of a plastic product, the importance of life cycle assessment (LCA) and circularity is underscored. MPs-related ecosystem degradation has not yet been adequately incorporated into LCA, a tool for evaluating the environmental performance of product and technology life cycles. It is a technique that is designed to quantify the environmental effects of a product from its inception to its demise, and it is frequently employed in the context of plastics. The control of MPs is necessary due to the growing concern that MPs pose as a newly emergent potential threat. This is due to the consequences of their use. This paper provides a critical analysis of the formation, distribution, and methods used for detecting MPs. The effects of MPs on ecosystems and human health are also discussed, which posed a great challenge to conduct an LCA related to MPs. The socio-economic impacts of MPs and their management are also discussed. This paper paves the way for understanding the ecotoxicological impacts of the emerging MP threat and their associated issues to LCA and limits the environmental impact of plastic.

Response of denitrifying anaerobic methane oxidation processes in freshwater and marine sediments to polyvinyl chloride microplastics

Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) plays a crucial role in mitigating methane (CH4) in natural environments. The increasing presence of microplastics (MPs) in these environments due to human activities is a growing concern. However, the impact of MPs on n-DAMO microorganisms and their role in greenhouse gas regulation, particularly CH4 reduction, remains unclear. This study investigates the effects of polyvinyl chloride (PVC) MPs on n-DAMO activity and the associated microbial communities in freshwater and marine sediments at varying concentrations of (R0/M0-no addition, R1/M1-0.5 %, R2/M2-2%). The results showed that the presence of MPs significantly increased the n-DAMO rate (2.89-3.58 nmol 13CO2 g-1 d-1) compared to the control groups (R0: 1.29 nmol 13CO2 g-1 d-1, M0: 0.11 nmol 13CO2 g-1 d-1), with marine sediments showing a more pronounced response. Additionally, the proportional contribution of nitrate-DAMO processes increased following MP exposure. The presence of PVC MPs also altered the microbial diversity of n-DAMO. Upon the addition of MPs, the microbial community composition of n-DAMO in marine sediments changed more significantly. This study provides the first evidence of a positive impact of PVC MPs on n-DAMO processes, suggesting that the presence of PVC MPs in sediments could potentially contribute to the reduction of CH4 emissions.

Microplastic pollution in tropical coral reef ecosystems from the coastal South China Sea and their impacts on corals in situ

Coral reefs possess extremely high ecological value in tropical and subtropical waters worldwide. Microplastics as emerging and pervasive pollutants pose a great threat to the health of coral ecosystems. However, in situ studies on microplastics pollution and its impacts in coral ecosystems globally are limited. The occurrence characteristics of microplastics in the environment mediums and reef-dwelling organisms were investigated in coral reef areas from the southern Hainan Island, and the impacts of microplastics on corals in situ were evaluated in this study. Average microplastics abundance was 9.48 items L-1 in seawater, 190.00 items kg-1 in sediment, 0.36 items g-1 in coral, 1.50 items g-1 in shellfish, 0.48 items g-1 in fish gill, and 1.71 items g-1 in fish gastrointestinal tract. The prevalent microplastics in the above samples were characterized as being less than 1000 µm in size, fibrous, and transparent, with predominant polymer types as polyethylene terephthalate, polypropylene, polyethylene, and rayon. The microplastic enrichment capacity of different corals varied (Pocillopora > Acropora > Sinularia). Notably, microplastics were more abundant on the surface of corals compared to their interiors, with distinct characteristics observed, including larger-sized (>500 µm) and fiber-shaped polyethylene terephthalate microplastics on the surface and smaller-sized (20-200 µm) fragmented polyethylene microplastics within coral interiors. Furthermore, the investigation showed species-specific impacts of microplastics on corals in situ, including photosynthetic activity of photosymbionts and antioxidant and immune activities of corals. Furthermore, the ecological risks of microplastics were minor across most environmental media in the studied areas, with exceptions in the bottom seawater and surface sediment of YLW, which exhibited extreme and medium risk levels, respectively. Coral risk levels were generally medium, except for dangerous levels in DDH and high levels in LHT. The potential sources of microplastics in the marginal reefs of southern Hainan Island were primarily tourism, residential, and fishing activities.

Environmental occurrence and ecotoxicological risks of plastic leachates in aquatic and terrestrial environments

Plastic pollution poses a significant threat to environmental and human health, with microplastics widely distributed across various ecosystems. Although current ecotoxicological studies have primarily focused on the inherent toxicity of plastics in natural environments, the role of chemical additives leaching from plastics into the environment remains underexplored despite their significant contribution to the overall toxic potential of plastics. Existing systematic studies on plastic leachates have often examined isolated additive compounds, neglecting the ecotoxicological effects of multiple compounds present in plastic leachates. Additionally, most previous research has focused on aquatic environments, overlooking the leaching mechanisms and ecological risks to diverse species with various ecological roles in aquatic and terrestrial ecosystems. This oversight hinders comprehensive ecological risk assessments. This study addresses these research gaps by reviewing the environmental occurrence of plastic leachates and their ecotoxicological impacts on aquatic and terrestrial ecosystems. Key findings reveal the pervasive presence of plastic leachates in various environments, identifying common additives such as phthalates, polybrominated diphenyl ethers (PBDEs), bisphenol A (BPA), and nonylphenols (NPs). Ecotoxicologically, chemical additives leaching from plastics under specific environmental conditions can influence their bioavailability and subsequent uptake by organisms. This review proposes a novel ecotoxicity risk assessment framework that integrates chemical analysis, ecotoxicological testing, and exposure assessment, offering a comprehensive approach to evaluating the risks of plastic leachates. This underscores the importance of interdisciplinary research that combines advanced analytical techniques with ecotoxicological studies across diverse species and environmental conditions to enhance the understanding of the complex impacts of plastic leachates and inform future research and regulatory policies.

Use of a nanoplastic carrier for assessing the aquatic toxicity of an organo-phosphite polymer additive

This work reports the production of nanoplastics (NPs) from polypropylene (PP) free of the antioxidant Irgafos® 168 (IRG) and alkane oligomers (ALK). PP pellets were milled into a powder with particle sizes in the 100-500 μm range. Additives and oligomers were removed using dichloromethane, and the powder exposed to UV irradiation, followed by filtration through 1 μm filters. PP suspensions, free of antioxidant and oligomers, were reloaded with IRG and ALK to their original commercial concentrations. This approach allowed testing the aquatic toxicity of IRG at concentrations compromised by water solubility limits. Toxicity assays using the cladoceran Daphnia magna with 24-48 h immobilization of neonates as endpoint showed toxicity for NPs containing IRG, with EC20 (48 h) in the 1.8-3.5 mg/L range, that corresponded to IRG exposure <1.2 μg/L. Suspensions of PP containing ALK, but not IRG, exhibited low toxicity (EC20 > 20 mg/L). The results allowed estimating the toxicity of IRG with a EC50 value of 3.3 ± 1.1 μg/L. Assays with different proportions of IRG and its oxidized form showed no differences. This work demonstrated the aquatic toxicity of IRG, for which there were no previous data, and developed a method for testing the toxicity of non-polar additives without being limited by their solubility.

The difference between tire wear particles and polyethylene microplastics in stormwater filtration systems: Perspectives from aging process, conventional pollutants removal and microbial communities

Tire wear particles (TWPs) in stormwater runoff have been widely detected and were generally classified into microplastics (MPs). TWPs and conventional MPs can be intercepted and accumulated in stormwater filtration systems, but their impacts on filtration, adsorption and microbial degradation processes of conventional pollutants (organic matters, nitrate and ammonium) have not been clarified. TWPs are different from MPs in surface feature, chemical components, adsorption ability and leaching of additives, which might lead to their different impacts on conventional pollutants removal. In this study, five different levels of aged polyethylene MPs (PEMPs) and aged TWPs contamination in stormwater filtration systems were simulated using thirty-three filtration columns. Results showed that ultraviolet aging treatment was less influential for the aging of TWPs than that of PEMPs, the specific surface area of aged PEMPs (1.603 m2/g) was over two times of unaged TWPs (0.728 m2/g) in the same size. Aged PEMPs and aged TWPs had different impacts on conventional pollutants removal performance and microbial communities, and the difference might be enlarged with exposure duration. The intensified aged PEMPs contamination generally promoted conventional pollutants removal, whereas aged TWPs showed an opposite trend. Mild contamination (0.01% and 0.1%, wt%) of aged PEMP/TWPs was beneficial to the richness and diversity of microbial communities, whereas higher contamination of aged PEMPs/TWPs was harmful. Aged PEMPs and TWPs had different impact on microbial community structure. Overall, the study found that TWPs were more detrimental than PEMPs in filtration systems. The research underscores the need for more comprehensive investigation into the occurrence, effects and management strategies of TWPs, as well as the importance of distinguishing between TWPs and MPs in future studies.

A newly-constructed technology to remove and recover diethyl phthalate from wastewater by using the instant plasticization assembly ability of PVC

Diethyl phthalate (DEP) is a typical environmentally organic pollutant, widely used in the production process of polyvinyl chloride (PVC) to improve the flexibility of plastic materials. Its interaction with living organisms can inflict considerable harm to reproductive system functions. This research aims to utilize tetrahydrofuran (THF) to selectively break the chemical bonds in PVC molecules to provide more adsorption sites. Then incorporates the plasticizing assembly process of PVC to instantly remove and recover DEP from wastewater, achieving waste utilization, and sustainable environmental development. The research found that PTFR with a concentration of around 75 mg/L shows the best DEP removal efficiency. Sequencing batch processing removes more DEP compared to direct processing under the same material usage conditions. Furthermore, the recovery rate of DEP can reach over 90%. The technology demonstrates notable enhancements in removal efficiency and adsorption duration when compared to conventional adsorption techniques. This research has established an instant and efficient method for DEP removal, providing a new idea and technology for plasticizer treatment in practical wastewater.

Towards harmonization of metal(loid)s determination in conventional and compostable plastics: Comparison of acid digestion protocols in LDPE and PBAT/TPS blends

The determination of metal-containing additives in plastic materials via acid digestion protocols has attracted growing interest to address potential environmental implications. However, the lack of protocol harmonization hinders data comparability within the literature. Here, six acid digestion protocols were employed to determine the metal(loid) content in plastics: these included three different acid mixtures (HNO3 combined with H2SO4, HCl or H2O2) for microwave-assisted digestion, with or without an additional room-temperature digestion step with H2O2. Each protocol was first validated for seven metal(loid)s (As, Cd, Cr, Pb, Sb, Sn and Zn) using a low-density polyethylene (LDPE) certified reference material (ERM®-EC681m). Then, validated protocols were applied on end-use materials, including conventional (i.e., LDPE) and compostable (i.e., PBAT/TPS) plastics. The combination of H2SO4 and HNO3 with a further digestion step with H2O2 was the most suitable protocol: it successfully passed validation thresholds for all metal(loid)s (recoveries in the range 98.6-101.0 %) and yielded the highest concentrations in end-use materials. All other protocols resulted in a less efficient digestion of the sample matrix, leading to lower recoveries and the formation of solid residues. Notably, end-use plastics showed a great variability in metal(loid) concentrations, likely due to their additive-rich composition, in contrast to the minimal content of acid-soluble additives of the reference material. This study represents an initial step towards the harmonization of acid digestion protocols and highlights new challenges in accurately analyzing end-use plastic materials, due to their complex additive composition.

Advantages of online supercritical fluid extraction and chromatography hyphenated to mass spectrometry to analyse plastic additives in laboratory gloves

Plastic additives are introduced in plastic material formulations, along with organic polymers, to offer different properties such as stability, plasticity or color. However, plastic additives may migrate from the plastic material to the content (in case of plastic containers) or to the material in contact with the plastic, like human skin. In the case of plastic medical devices, this migration is of particular interest, as plastic additives may be deleterious to health. In the present paper, we examined the interest of combining supercritical fluid extraction (SFE) to supercritical fluid chromatography (SFC) hyphenated to mass spectrometry (MS) in an online system to characterize plastic additives in laboratory gloves, taken as samples of medical devices. A set of target compounds comprising 18 plasticizers, 4 antioxidants and 2 lubricants was defined and their detectability with MS was examined, where it appeared that electrospray ionization (ESI) provided better detectability than atmospheric pressure chemical ionization (APCI). After examining possible stationary phases with the help of Derringer desirability function, an isocratic chromatographic method (CO2:methanol 95:5) was developed on Shim-pack UC Phenyl column. The extraction method was examined with a 3-level full factorial design of experiments to optimize the extraction temperature (40 °C) and pressure (200 bar). The online SFE-SFC-MS method was compared to offline methods where the samples were extracted with liquid solvents at atmospheric pressure or high pressure then analysed with SFC-MS. In all cases, offline methods showed significant contaminants (like the oleamide lubricant) issuing from laboratory plastic materials as nitrogen drying station, syringes and filters, while the online method allowed a complete elimination of laboratory contaminations. Furthermore, the online method saved time, solvents and laboratory consumables. It will also show that transferring a compressible fluid from a loading loop is favourable to high efficiency, as the resulting chromatographic peaks are much thinner than when transferring a liquid. Compared to injecting liquid heptane, the efficiency increase was 3.4-fold, while compared to injecting liquid methanol (a common practice in SFC), the efficiency increase was 13-fold. Finally, the additive composition of different laboratory gloves was compared.

New Insights into the Mechanisms of Toxicity of Aging Microplastics

Nowadays, synthetic polymer (plastic) particles are ubiquitous in the environment. It is known that for several decades microplastics (MPs) have been accumulating in the World Ocean, becoming available to a large variety of marine organisms. Particularly alarming is the accumulation of aging plastic particles, as the degradation processes of such particles increase their toxicity. The diverse display of negative properties of aging MPs and its effect on biota are still poorly understood. In this study, in vitro experiments modeling the interaction of pristine and UV-irradiated aging polypropylene (PP) fragments with hemocytes and mitochondria of bivalve mollusks Mytilus sp. were performed. The appearance of free radicals in the environment was recorded by spectral characteristics of indicator dyes-methylene blue (MB) and nitroblue tetrazolium (NBT). It was found that due to photooxidation, aging PP fragments sorbed more than threefold MB on their modified surface compared to pristine samples of this polymer. Using NBT, the formation of reactive oxygen species in seawater in the presence of pristine and photoactivated PP was recorded. It was also found that photodegraded PP fragments largely stimulated the development of lipid peroxidation processes in mitochondrial membranes and reduced the stability of hemocyte lysosome membranes compared to pristine PP fragments. In general, the results obtained concretize and supplement with experimental data the previously stated hypothesis of toxicity of aging MPs.

Microplastic pollution in the surface waters of the zuari river, goa, india

Limited research has been conducted on microplastic (MP) contamination in the rivers of Goa. To address this gap, this study examines the levels of MP contamination in the surface water of the Zuari River, Goa. We investigate the abundance, characteristics (size, shape, colour, and polymer composition), and risk assessment of MPs. MPs were detected at all sampling stations in the Zuari River, with concentrations varying from 0.01 particles/L (S3) to 1.38 particles/L (S13). The average abundance of MPs in the water samples was 0.28 ± 0.35 particles/L. MPs were more common in the 0.3-1 mm size range (51.70%) than in the 1-5 mm range (48.30%). The most common MP shapes observed were fibers (37.88%) and fragments (29.66%). FTIR analysis confirmed the presence of polyethylene terephthalate, high-density polyethylene, polypropylene, and polyacrylamide carboxyl-modified MPs. The Pollution Load Index (PLI) showed an average value of 3.8, indicating significant contamination (PLI > 1). Scanning electron microscopy (SEM) revealed various degradation features such as pits, scratches, grooves, and cracks on the MPs surfaces, while energy dispersive X-ray spectroscopy (EDS) detected metals on the MP's surfaces. This study provides key insights into MP pollution in the Zuari River's surface water and lays the groundwork for future research and management strategies in the region.

Screening the release of chemicals and microplastic particles from diverse plastic consumer products into water under accelerated UV weathering conditions

Photodegradation of plastic consumer products is known to accelerate weathering and facilitate the release of chemicals and plastic particles into the aquatic environment. However, these processes are complex. In our presented pilot study, eight plastic consumer products were leached in distilled water under strong ultraviolet (UV) light simulating eight months of Central European climate and compared to their respective dark controls (DCs). The leachates and formed plastic particles were exploratorily characterized using a range of chemical analytical tools to describe degradation and leaching processes. These techniques covered (a) microplastic analysis, showing substantial liberation of plastic particles further increased under UV exposure, (b) non-targeted mass spectrometric characterization of the leachates, revealing several hundreds of chemical features with typically only minor agreement between the UV exposure and the corresponding DCs, (c) target analysis of 71 organic analytes, of which 15 could be detected in at least one sample, and (d) metal(loid) analysis, which revealed substantial release of toxic metal(loid)s further enhanced under UV exposure. A data comparison with the US-EPA's ToxVal and ToxCast databases showed that the detected metals and organic additives might pose substantial health and environmental concerns, requiring further study and comprehensive impact assessments.

Leachates from plastics and bioplastics reduce lifespan, decrease locomotion, and induce neurotoxicity in Caenorhabditis elegans

Plastic pollution continuously accumulates in the environment and poses a global threat as it fragments into microplastics and nanoplastics that can harm ecosystems. To reduce the accumulation of microplastic and nanoplastic pollution, bioplastics made from biodegradable materials are promoted as a more sustainable alternative because it can degrade faster than plastics. However, plastics also leach out chemicals as they degrade and disintegrate, but the potential toxicity of these chemicals leaching out from plastics and especially bioplastics is poorly explored. Here, we determined the composition of leachates from plastics and bioplastics and tested their toxicity in Caenorhabditis elegans. LC-MS analysis of the leachates revealed that bioplastics leached a wider array of chemicals than their counterpart plastics. Toxicity testing in our study showed that the leachates from plastics and bioplastics reduced lifespan, decreased locomotion, and induced neurotoxicity in C. elegans. Leachates from bioplastics reduced C. elegans lifespan more compared to leachates from plastics: by 7%-31% for bioplastics and by 6%-15% for plastics. Leachates from plastics decreased locomotion in C. elegans more compared to leachates from bioplastics: by 8%-34% for plastics and by 11%-24% for bioplastics. No changes were observed in the ability of the C. elegans to respond to mechanical stimuli. The leachates induced neurotoxicity in the following neurons at varying trends: cholinergic neurons by 0%-53% for plastics and by 30%-42% for bioplastics, GABAergic neurons by 3%-29% for plastics and by 10%-23% for bioplastics, and glutamatergic neurons by 3%-11% for plastics and by 15%-29% for bioplastics. Overall, our study demonstrated that chemicals leaching out from plastics and bioplastics can be toxic, suggesting that both plastics and bioplastics pose ecotoxicological and human health risks.

Critical review on unveiling the toxic and recalcitrant effects of microplastics in aquatic ecosystems and their degradation by microbes

Production of synthetic plastic obtained from fossil fuels are considered as a constantly growing problem and lack in the management of plastic waste has led to severe microplastic pollution in the aquatic ecosystem. Plastic particles less than 5mm are termed as microplastics (MPs), these are pervasive in water and soil, it can also withstand longer period of time with high durability. It can be broken down into smaller particles and can be adsorbed by various life-forms. Most marine organisms tend to consume plastic debris that can be accumulated easily into the vertebrates, invertebrates and planktonic entities. Often these plastic particles surpass the food chain, resulting in the damage of various organs and inhibiting the uptake of food due to the accumulation of microplastics. In this review, the physical and chemical properties of microplastics, as well as their effects on the environment and toxicity of their chemical constituents are discussed. In addition, the paper also sheds light on the potential of microorganisms such as bacteria, fungi, and algae which play a pivotal role in the process of microplastics degradation. The mechanism of microbial degradation, the factors that affect degradation, and the current advancements in genetic and metabolic engineering of microbes to promote degradation are also summarized. The paper also provides information on the bacterial, algal and fungal degradation mechanism including the possible enzymes involved in microplastic degradation. It also investigates the difficulties, limitations, and potential developments that may occur in the field of microbial microplastic degradation.

Full-chain analysis on emerging contaminants in soil: Source, migration and remediation

Emerging contaminants (ECs) are gaining attention due to their prevalence and potential negative impacts on the environment and human health. This paper provides a comprehensive review of the status and trends of soil pollution caused by ECs, focusing on their sources, migration pathways, and environmental implications. Significant ECs, including plastics, synthetic polymers, pharmaceuticals, personal care products, plasticizers, and flame retardants, are identified due to their widespread use and toxicity. Their presence in soil is attributed to agricultural activities, urban waste, and wastewater irrigation. The review explores both horizontal and vertical migration pathways, with factors such as soil type, organic matter content, and moisture levels influencing their distribution. Understanding the behavior of ECs in soil is critical to mitigating their long-term risks and developing effective soil remediation strategies. The paper also examines the advantages and disadvantages of in situ and ex situ treatment approaches for ECs, highlighting optimal physical, chemical, and biological treatment conditions. These findings provide a fundamental basis for addressing the challenges and governance of soil pollution induced by ECs.

Exploring polystyrene weathering behavior: From surface traits to micro(nano)plastics and additives release

Plastic weathering in the natural environment is a dynamic and complex process, where the release of microplastics, nanoplastics and additives poses potential threats to ecosystems. Understanding the release of different weathering products from plastics is crucial for predicting and assessing the environmental hazards of plastics. This study systematically explored these phenomena by exposing polystyrene (PS) to UV irradiation and mechanical agitation for different durations (1 day, 5 days, 10 days, 20 days). The degree of aging, yellowing, brittleness, and the abundance of carbonyl (CO) functional groups in PS were all gradually increasing over time. The weathering pattern of PS surfaces manifested as initial particle oxidation followed by later cracks or flakes formation. The release of products was positively correlated with the aging degree of plastics, as well as among the various released products. Laser infrared and Raman tests indicated that, for microplastics, the size range of 10-20 μm consistently dominated over time, while the primary size range of nanoplastics shifted towards smaller sizes. Additives and other soluble products were prone to release from weathering plastics, with 20 different chemicals detected after 20 d. The release of plastic additives was closely related to aging time, additive type, and quantity. This study contributes to our understanding of the weathering process of plastics, clarifies the release patterns of products over time, and the relationships among different products. It helps predict and assess the environmental pollution caused by plastics.

Assessment of biodegradation and toxicity of alternative plasticizer di(2-ethylhexyl) terephthalate: Impacts on microbial biofilms, metabolism, and reactive oxygen species-mediated stress response

Although di(2-ethylhexyl) terephthalate (DOTP) is being widely adopted as a non-phthalate plasticizer, existing research primarily focuses on human and rat toxicity. This leaves a significant gap in our understanding of their impact on microbial communities. This study assessed the biodegradation and toxicity of DOTP on microbes, focusing on its impact on biofilms and microbial metabolism using Rhodococcus ruber as a representative bacterial strain. DOTP is commonly found in mass fractions between 0.6 and 20% v/v in various soft plastic products. This study used polyvinyl chloride films (PVC) with varying DOTP concentrations (range 1-10% v/v) as a surface for analysis of biofilm growth. Cell viability and bacterial stress responses were tested using LIVE/DEAD™ BacLight™ Bacterial Viability Kit and by the detection of reactive oxygen species using CellROX™ Green Reagent, respectively. An increase in the volume of dead cells (in the plastisphere biofilm) was observed with increasing DOTP concentrations in experiments using PVC films, indicating the potential negative impact of DOTP on microbial communities. Even at a relatively low concentration of DOTP (1%), signs of stress in the microbes were noticed, while concentrations above 5% compromised their ability to survive. This research provides a new understanding of the environmental impacts of alternative plasticizers, prompting the need for additional research into their wider effects on both the environment and human health.

Photocatalytic degradation of organophosphorus flame retardants in aqueous solutions: a review and future prospects

The widespread use of organophosphorus flame retardants (OPFRs) in industrial and household products increases the risk of their environmental exposure, posing a serious threat to ecosystems and human health. Photocatalytic technology has been widely used in wastewater treatment due to its high efficiency, mild reaction conditions, and robustness. This review summarizes the current status of research on photocatalytic degradation of OPFRs, focusing on the effect of different types of catalysts on the degradation efficiency, the effects of pH, and co-existing inorganic and organic ions. And pH and co-existing inorganic mainly affect the active oxygen and the active surface sites of the catalyst. In addition, toxicological calculations of the intermediates of the degradation pathway using T.E.S.T. and ECOSAR showed that photocatalysis could effectively reduce the toxicity of OPFRs. Development of new photocatalytic materials, in-depth study of the degradation mechanism of different catalysts and flame retardants, and attention to practical applications and toxicity issues can be the development direction of future research.

Looking beyond the obvious: The ecotoxicological impact of the leachate from fishing nets and cables in the marine mussel Mytilus galloprovincialis

Once in the marine environment, fishing nets and cables undergo weathering, breaking down into micro and nano-size particles and leaching plastic additives, which negatively affect marine biota. This study aims to unravel the ecotoxicological impact of different concentrations of leachate obtained from abandoned or lost fishing nets and cables in the mussel Mytilus galloprovincialis under long-term exposure (28 days). Biochemical biomarkers linked to antioxidant defense system, xenobiotic biotransformation, oxidative damage, genotoxicity, and neurotoxicity were evaluated in different mussel tissues. The chemical nature of the fishing nets and cables and the chemical composition of the leachate were assessed and metals, plasticizers, UV stabilizers, flame retardants, antioxidants, dyes, flavoring agents, preservatives, intermediates and photo initiators were detected. The leachate severely affected the antioxidant and biotransformation systems in mussels' tissues. Following exposure to 1 mg·L-1 of leachate, mussels' defense system was enhanced to prevent oxidative damage. In contrast, in mussels exposed to 10 and 100 mg·L-1 of leachate, defenses failed to overcome pro-oxidant molecules, resulting in genotoxicity and oxidative damage. Principal component analysis (PCA) and Weight of Evidence (WOE) evaluation confirmed that mussels were significantly affected by the leachate being the hazard of the leachate concentrations of 10 mg·L-1 ranked as major, while 1 and 100 mg·L-1 was moderate. These results highlighted that the leachate from fishing nets and cables can be a threat to the heath of the mussel M. galloprovincialis.

Prevalence of synthetic phenolic antioxidants in food contact materials from China and their implications for human dietary exposure through take-away food

The application of disposable tableware has increased substantially in recent times due to the rapidly growing food delivery business in China. Synthetic phenolic antioxidants (SPAs) are widely used in food contact materials (FCMs) to delay the process of oxidation; however, their compositions, concentrations, and potential health hazards remain unclear. Therefore, FCMs comprised of five materials obtained from 19 categories (n = 118) in China were analyzed for SPAs concentrations. FCMs have been found to contain a variety of SPAs, with ∑SPAs concentrations ranging from 44.18 to 69,485.12 μg/kg (median: 2615.63 μg/kg). The predominant congeners identified in the sample include 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP), and 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) with a median concentration of 885.75, 555.45 and of 217.44 μg/kg, respectively. Milky tea paper cups, instant noodle buckets, milky teacups, and disposable cups showed high levels of SPAs. 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (AO 2246) was predominantly detected in polyethylene and polyethylene terephthalate-based products. The migration test identified disposable plastic cups and bowls as the predominant FCMs and 2,4-DTBP as the dominant SPA. The exposure risk of SPAs decreased with age. In children, the estimated daily intake of ∑SPAs from FCMs was determined to be 17.56 ng/kg body weight/day, which was 8.3 times higher than that of phthalic acid esters. The current findings indicate the potential ingestion risk of SPAs during the daily life application of multiple FCM categories.

Optimizing Antimony Speciation Analysis via Frontal Chromatography-ICP-MS to Explore the Release of PET Additives

Antimony (Sb) contamination poses significant environmental and health concerns due to its toxic nature and widespread presence, largely from anthropogenic activities. This study addresses the urgent need for an accurate speciation analysis of Sb, particularly in water sources, emphasizing its migration from polyethylene terephthalate (PET) plastic materials. Current methodologies primarily focus on total Sb content, leaving a critical knowledge gap for its speciation. Here, we present a novel analytical approach utilizing frontal chromatography coupled with inductively coupled plasma mass spectrometry (FC-ICP-MS) for the rapid speciation analysis of Sb(III) and Sb(V) in water. Systematic optimization of the FC-ICP-MS method was achieved through multivariate data analysis, resulting in a remarkably short analysis time of 150 s with a limit of detection below 1 ng kg-1. The optimized method was then applied to characterize PET leaching, revealing a marked effect of the plastic aging and manufacturing process not only on the total amount of Sb released but also on the nature of leached Sb species. This evidence demonstrates the effectiveness of the FC-ICP-MS approach in addressing such an environmental concern, benchmarking a new standard for Sb speciation analysis in consideration of its simplicity, cost effectiveness, greenness, and broad applicability in environmental and health monitoring.

Temperature fluctuation in soil alters the nanoplastic sensitivity in wheat

Despite the wide acknowledgment that plastic pollution and global warming have become serious agricultural concerns, their combined impact on crop growth remains poorly understood. Given the unabated megatrend, a simulated soil warming (SWT, +4 °C) microcosm experiment was carried out to provide a better understanding of the effects of temperature fluctuations on wheat seedlings exposed to nanoplastics (NPs, 1 g L-1 61.71 ± 0.31 nm polystyrene). It was documented that SWT induced oxidative stress in wheat seedlings grown in NPs-contaminated soil, with an 85.56 % increase in root activity, while decreasing plant height, fresh weight, and leaf area by 8.72 %, 47.68 %, and 15.04 % respectively. The SWT also resulted in reduced photosynthetic electron-transfer reaction and Calvin-Benson cycle in NPs-treated plants. Under NPs, SWT stimulated the tricarboxylic acid (TCA) metabolism and bio-oxidation process. The decrease in photosynthesis and the increase in respiration resulted in an 11.94 % decrease in net photosynthetic rate (Pn). These results indicated the complicated interplay between climate change and nanoplastic pollution in crop growth and underscored the potential risk of nanoplastic pollution on crop production in the future climate.

Probing Long-Term Impacts: Low-Dose Polystyrene Nanoplastics Exacerbate Mitochondrial Health and Evoke Secondary Glycolysis via Repeated and Single Dosing

Nanoplastics (NPs) are omnipresent in the environment and contribute to human exposure. However, little is known regarding the long-term effects of NPs on human health. In this study, human intestinal Caco-2 cells were exposed to polystyrene nanoplastics (nanoPS) in an environmentally relevant concentration range (102-109 particles/mL) under two realistic exposure scenarios. In the first scenario, cells were repeatedly exposed to nanoPS every 2 days for 12 days to study the long-term effects. In the second scenario, only nanoPS was added once and Caco-2 cells were cultured for 12 days to study the duration of the initial effects of NPs. Under repeated dosing, initial subtle effects on mitochondria induced by low concentrations would accrue over consistent exposure to nanoPS and finally lead to significant impairment of mitochondrial respiration, mitochondrial mass, and cell differentiation process at the end of prolonged exposure, accompanied by significantly increased glycolysis over the whole exposure period. Single dosing of nanoPS elicited transient effects on mitochondrial and glycolytic functions, as well as increased reactive oxygen species (ROS) production in the early phase of exposure, but the self-recovery capacity of cells mitigated these effects at intermediate culture times. Notably, secondary effects on glycolysis and ROS production were observed during the late culture period, while the cell differentiation process and mitochondrial mass were not affected at the end. These long-term effects are of crucial importance for comprehensively evaluating the health hazards arising from lifetime exposure to NPs, complementing the extensively observed acute effects associated with prevalent short-term exposure to high concentrations. Our study underlines the need to study the toxicity of NPs in realistic long-term exposure scenarios such as repeated dosing.

Effects of biodegradable microplastics and straw addition on soil greenhouse gas emissions

Large pieces of plastic are transformed into microplastic particles through weathering, abrasion, and ultraviolet radiation, significantly impacting the soil ecosystem. However, studies on biodegradable microplastics replacing traditional microplastics as agricultural mulching films to drive the biogeochemical processes influenced by GHG are still in their initial stages, with limited relevant reports available. This study sought to investigate the effects of microplastic and straw addition on CO2 and N2O emissions in different soils. Herein, yellow-brown soil (S1) and fluvo-aquic soil (S2) were utilized, each treated with three different concentrations of PLA (polylactic acid) microplastics (0.25%, 2%, and 7% w/w) at 25 °C for 35 days, with and without straw addition. The results showed that straw (1% w/w) significantly increased soil CO2 by 4.1-fold and 3.2-fold, respectively, and N2O by 1.8-fold and 1.8-fold, respectively, in cumulative emissions in S1 and S2 compared with the control. PLA microplastics significantly increased CO2 emissions by 71.5% and 99.0% and decreased N2O emissions by 30.1% and 24.7% at a high concentration (7% w/w, PLA3) in S1 and S2 compared with the control, respectively. The same trend was observed with the addition of straw and microplastics together. Structural equation modeling and redundancy analysis confirmed that soil physiochemical parameters, enzyme and microbial activities are key factors regulating CO2 and N2O emissions. The addition of microplastics is equivalent to the addition of carbon sources, which can significantly affect DOC, MBC, SOC and the abundance of carbon-associated bacteria (CbbL), thereby increasing soil CO2 emissions. The addition of microplastics alone inhibited the activity of nitrogen cycling enzymes (urease activity), increasing the abundance of denitrifying microbes. However, adding a high amount of microplastics and straw together released plastic additives, inhibiting microbial abundance and reducing the nitrogen cycle. These effects decreased NH4+-N and increased NO3--N, resulting in decreased N2O emissions. This study indicates that biodegradable microplastics could reduce soil plastic residue pollution through degradation. However, their use could also increase CO2 emissions and decrease N2O emissions. Consequently, this research lays the groundwork for further investigation into the implications of utilizing biodegradable microplastics as agricultural mulch, particularly concerning soil geochemistry and GHG emissions.

Toxic mechanism in Daphnia magna due to phthalic acid esters and CuO nanoparticles co-exposure: The insight of physiological, microbiomic and metabolomic profiles

Various phthalic acid esters (PAEs) such as dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) co-exist with nanopollutants in aquatic environment. In this study, Daphnia magna was exposed to nano-CuO and DBP or BBP at environmental relevant concentrations for 21-days to investigate these combined toxic effects. Acute EC50 values (48 h) of nano-CuO, DBP, and BBP were 12.572 mg/L, 8.978 mg/L, and 4.785 mg/L, respectively. Results showed that co-exposure with nano-CuO (500 μg/L) for 21 days significantly enhanced the toxicity of DBP (100 μg/L) and BBP (100 μg/L) to Daphnia magna by 18.37% and 18.11%, respectively. The activities of superoxide dismutase, catalase, and glutathione S-transferase were enhanced by 10.95% and 14.07%, 25.63% and 25.91%, and 39.93% and 35.01% in nano-CuO+DBP and nano-CuO+BBP treatments as compared to the individual exposure groups, verifying that antioxidative defense responses were activated. Furthermore, the co-exposure of nano-CuO and PAEs decreased the population richness and diversity microbiota, and changed the microbial community composition in Daphnia magna. Metabolomic analysis elucidated that nano-CuO + PAEs exposure induced stronger disturbance on metabolic network and molecular function, including amino acid, nucleotides, and lipid metabolism-related metabolic pathways, as comparison to PAEs single exposure treatments. In summary, the integration of physiological, microflora, and untargeted metabolomics analysis offers a fresh perspective into the potential ecological risk associated with nanopollutants and phthalate pollution in aquatic ecosystems.

Bisphenol A sorption on commercial polyvinyl chloride microplastics: Effects of UV-aging, biofilm colonization and additives on plastic behaviour in the environment

Chemical additives are important components in commercial microplastics and their leaching behaviour has been widely studied. However, little is known about the potential effect of additives on the adsorption/desorption behaviour of pollutants on microplastics and their subsequent role as vectors for pollutant transport in the environment. In this study, two types of commercial polyvinyl chloride (PVC1 and PVC2) microplastics were aged by UV irradiation and biotic modification via biofilm colonization to investigate the adsorption and desorption behaviour of bisphenol A (BPA). Surface cracks and new functional groups (e.g., O-H) were found on PVC1 after UV irradiation, which increased available adsorption sites and enhanced H‒bonding interaction, resulting in an adsorption capacity increase from 1.28 μg/L to 1.85 μg/L. However, the adsorption and desorption capacity not showed significant changes for PVC2, which might be related to the few characteristic changes after UV aging with the protection of light stabilizers and antioxidants. The adsorption capacity ranged from 1.28 μg/L to 2.06 μg/L for PVC1 and PVC2 microplastics, and increased to 1.62 μg/L-2.95 μg/L after colonization by biofilms. The increased adsorption ability might be related to the N-H functional group, amide groups generated by microorganisms enhancing the affinity for BPA. The opposite effect was observed for desorption. Plasticizers can be metabolized during biofilm formation processes and might play an important role in microorganism colonization. In addition, antioxidants and UV stabilizers might also indirectly influence the colonization of microorganisms' on microplastics by controlling the degree to which PVC microplastics age under UV. The amount of biomass loading on the microplastics would further alter the adsorption/desorption behaviour of contaminants. This study provides important new insights into the evaluation of the fate of plastic particles in natural environments.

Photoaging Elevated the Genotoxicity of Polystyrene Microplastics to Marine Mussel Mytilus trossulus (Gould, 1850)

Micro-sized particles of synthetic polymers (microplastics) are found in all parts of marine ecosystems. This fact requires intensive study of the degree of danger of such particles to the life activity of hydrobionts and needs additional research. It is evident that hydrobionts in the marine environment are exposed to microplastics modified by biotic and abiotic degradation. To assess the toxic potential of aging microplastic, comparative studies were conducted on the response of cytochemical and genotoxic markers in hemocytes of the mussel Mytilus trossulus (Gould, 1850) after exposure to pristine and photodegraded (UV irradiation) polystyrene microparticles (µPS). The results of cytochemical tests showed that UV-irradiated µPS strongly reduced metabolism and destabilized lysosome membranes compared to pristine µPS. Using a Comet assay, it was shown that the nuclear DNA of mussel hemocytes showed high sensitivity to exposure to both types of plastics. However, the level of DNA damage was significantly higher in mussels exposed to aging µPS. It is suggested that the mechanism of increased toxicity of photo-oxidized µPS is based on free-radical reactions induced by the UV irradiation of polymers. The risks of toxic effects will be determined by the level of physicochemical degradation of the polymer, which can significantly affect the mechanisms of toxicity.