Polystyrene Microplastics Research Articles

Impacts of the coexistence of polystyrene microplastics and pesticide imidacloprid on soil nitrogen transformations and microbial communities

The pollution of agricultural soils by microplastics (MPs) and pesticides has attracted significant attention. However, the combined impact of MPs and pesticides on soil nitrogen transformation and microbial communities remains unclear. In this study, we conducted a 28-day soil incubation experiment, introducing polystyrene microplastics (PS-MPs) at concentrations of 0.1% and 10% (w/w) and pesticide imidacloprid at concentrations of 0.1 mg/kg and 1.0 mg/kg. Our aim was to investigate the individual and combined effects of these pollutants on nitrogen transformations and microbial communities in agricultural soils. Imidacloprid accelerated the decline in soil pH, while PS-MPs slowed the process. Imidacloprid hindered soil nitrification and denitrification processes, however, the presence of PS-MPs mitigated the inhibitory effects of imidacloprid. Based on microbial community and functional annotation analyses, this is mainly attributed to the different effects of PS-MPs and imidacloprid on soil microbial communities and the expression of key nitrogen transformation-related genes. Variance partitioning analysis and partial least squares path modeling analyses revealed that PS-MPs and imidacloprid indirectly influenced the microbial community structure, primarily through changes in soil pH. This study elucidates the mechanism through which the combined stress of MPs and pesticides in agricultural soils influence soil nitrogen transformation and microbial communities. The findings offer valuable insights for the systematic evaluation of the ecological risks posed by the coexistence of these pollutants.

Combined toxic effects of yessotoxin and polystyrene on the survival, reproduction, and population growth of rotifer Brachionus plicatilis at different temperatures.

Yessotoxin (YTX) is a disulfated toxin produced by harmful dinoflagellates and causes risks to aquatic animals. Polystyrene (PS) microplastics could absorb toxins in seawaters but pose threats to organism growth. In this study, the combined toxic effects of YTX (0, 20, 50, and 100 µg L-1) and PS (0, 5, and 10 µg mL-1) on the survival, reproduction, and population growth of marine rotifer Brachionus plicatilis at 20 °C, 25 °C, and 30 °C were evaluated. Results indicated that the survival time (S), time to first batch of eggs (Ft), total offspring per rotifer (Ot), generational time (T0), net reproduction rate (R0), intrinsic growth rate (rm), and population growth rate (r) of rotifers were inhibited by YTX and PS at 25 °C and 30 °C. Low temperature (20 °C) improved the life-table parameters T0, R0, and rm at YTX concentrations less than 100 µg L-1. Temperature, YTX, and PS had interactive effects on rotifers' S, Ft, Ot, T0, R0, rm, and r. The combined negative effects of YTX and PS on rotifers' survival, reproduction, and population growth were significantly enhanced at 30 °C. These findings emphasized the importance of environmental temperature in studying the interactive effects of microplastics and toxins on the population growth of zooplankton in eutrophic seawaters.

Mechanisms of eco-corona effects on micro(nano)plastics in marine medaka: Insights into translocation, immunity, and energy metabolism

Biomolecules, prevalent in the marine environment, can readily adsorb onto the surface of micro(nano)plastics (MNPs), forming eco-corona. This study indicated that 50 nm polystyrene nanoplastics (NP50), whether wrapped with eco-corona or not, can passively enter embryos, whereas 5 µm polystyrene microplastics (MP5) cannot. Additionally, translocation of MP5 from the intestine to the liver was observed in larvae, a process facilitated by eco-corona. Notably, eco-corona prolonged the retention time of MNPs in larvae. However, NP50 was more challenging to purify than MP5, irrespective of the presence of eco-corona. Interestingly, eco-corona degraded in the intestine during the uptake of MNPs, and the hard coronae that readily formed on NP50 may restrict the degradation rate. Although NP50 significantly disrupted larval microbiota homeostasis compared with MP5, eco-corona was more likely to exacerbate MP5′s damage to the intestine and liver by disrupting microbiota homeostasis. Additionally, NP50 caused more significant damage to immunity and energy metabolism compared with MP5, regardless of the presence of eco-corona. This study revealed that previously overlooked biomolecules in the marine environment can enhance the translocation of MNPs and subsequently exacerbate their toxic effects, providing theoretical support for assessing the ecological risks of MNPs in real environments.

Manifestation of polystyrene microplastic accumulation in brain with emphasis on morphometric and histopathological changes in limbic areas of Swiss albino mice

The widespread problem of microplastic (MP) contamination is becoming a major threat to the globe. Although most of the research to date has concentrated on the physiological impacts of MPs exposure, a relatively new field of study is beginning to examine its effects on the behaviour and limbic regions of the brain. In this study, exposure to polystyrene MPs (PS-MPs) for acute and sub-chronic durations negatively affected cognition and induced anxiety-like behaviour in mice. PS-MPs were detected in vital organs of mice, including the brain, which induced neurobehavioural and pathological changes in the limbic system. Furthermore, morphometric analysis revealed a significant decrease in the total cell count in the Dentate Gyrus (DG) and Cornu Ammonis (CA) regions of the hippocampus. Signs of neuronal injury and dystrophic changes were observed in the cortex, amygdala, and hypothalamus, potentially affecting anxiety and fear responses. Our study thus provides insight into the effect of PS-MPs on the neurobiology of the brain’s limbic system and related behavioural alterations.

Bioaccumulation Rate of Non-Biodegradable Polystyrene Microplastics in Human Epithelial Cell Lines.

Environment plastic accumulation has been attracting the attention of both political and scientific communities, who wish to reduce global pollution. Plastic items have been detected everywhere, from oceans to the air, raising concerns about the fate of plastics within organisms. Leaked plastics are ingested by animals, entering the food chain and eventually reaching humans. Although a lot of studies focused on the evaluation of plastic particles in the environment and living organisms have already been published, the behavior of plastic at the cellular level is still missing. Here, we analyzed the bioaccumulation and extrusion trend of two differently sized plastic particles (1 and 2 µm), testing them on three human epithelial cell lines (liver, lung, and gut) that represent epithelial sites mainly exposed to plastic. A different behavior was detected, and the major plastic uptake was shown by liver cells, where the 1 µm beads accumulated with a dose-dependent profile. Moreover, a 60% reduction in the content of 1 µm particles in cells was evaluated after plastic removal. Finally, the viability and proliferation of the three human cell lines were not significantly affected by both the 1 and 2 µm beads, suggesting that cells might have a defense mechanism against plastic exposure risk.

Toxicological consequences of polystyrene microplastics on Cirrhinus mrigala: effects on growth, body composition, nutrient digestibility, haematology and histopathology

Context Microplastics (MPs), whether originating from primary or secondary means, have emerged as a significant global issue nowadays. Aims The current research was designed to assess the toxicological consequences of polystyrene MPs (PS-MPs) on the growth, digestibility, body composition, haematology and histopathology of Cirrhinus mrigala fingerlings. Methods In this study, six test diets with different MP concentrations were used, including a control group (0% MPs) and groups with 0.5, 1, 1.5, 2 and 2.5% MPs in sunflower meal-based diets. For a 90-day duration, 270 fingerlings (6.54 ± 0.02 g fish−1) were placed in triplicate groups in tanks, with each tank consisting of 15 fingerlings, feeding at a rate equivalent to 5% of their live wet bodyweight. Key results The findings revealed a negative correlation between MP concentration and fingerlings performance, encompassing growth, digestibility, body composition, histopathology and hematology. Conclusions The results indicate that 2.5% MPs inclusion in C. mrigala adversely affects growth, digestibility, body composition, histopathology and hematology. Implications This research highlights the harmful effects of PS-MPs on C. mrigala fingerlings, emphasising urgent global action to address and mitigate aquatic ecosystem threats.

Sight of Aged Microplastics Adsorbing Heavy Metal Exacerbated Intestinal Injury: A Mechanistic Study of Autophagy-Mediated Toxicity Response.

Contaminant-bearing polystyrene microplastics (PSMPs) may exert significantly different toxicity profiles from their contaminant-free counterparts, with the role of PSMPs in promoting contaminant uptake being recognized. However, studies investigating the environmentally relevant exposure and toxic mechanisms of aged PSMPs binding to Cr are limited. Here, we show that loading of chromium (Cr) markedly alters the physicochemical properties and toxicological profiles of aged PSMPs. Specifically, Cr-bearing aged PSMPs induced severe body weight loss, oxidative stress (OS), autophagy, intestinal barrier injury, inflammation-pyroptosis response, and enteropathogen invasion in mice. Mechanistic investigations revealed that PSMPs@Cr exacerbated the OS, resulting in intestinal barrier damage and inflammation-pyroptosis response via overactivated Notch signaling and autophagy/cathepsin B/IL-1β pathway, respectively, which ultimately elevated mortality related to bacterial pathogen infection. In vitro experiments confirmed that autophagy-mediated reactive oxygen species (ROS) overproduction resulted in severe pyroptosis and impaired intestinal stem cells differentiation alongside the overactivation of Notch signaling in PSMPs@Cr-exposed organoids. Overall, our findings provide an insight into autophagy-modulated ROS overproduction within the acidic environment of autophagosomes, accelerating the release of free Cr from PSMPs@Cr and inducing secondary OS, revealing that PSMPs@Cr is a stable hazard material that induces intestinal injury. These findings provided a potential therapeutic target for environmental MPs pollution caused intestinal disease in patients.

Early-life exposure to polystyrene micro- and nanoplastics disrupts metabolic homeostasis and gut microbiota in juvenile mice with a size-dependent manner

Early-life exposure to different sizes of micro- and nanoplastics (MNPs) affects biotoxicity, which is related not only to the dose but also directly to particle size. In this study, pregnant ICR mice received drinking water containing 5 μm polystyrene microplastics (5 μm PS-MPs) or 0.05 μm polystyrene nanoplastics (0.05 μm PS-NPs) from pregnancy to the end of lactation. Histopathological and molecular biological detection, 16s rRNA sequencing for intestinal flora analysis, and targeted metabolomics analysis were used to look into how early-life exposure to MNPs of various sizes affects young mice's growth and development, gut flora, and metabolism. The outcomes showed that 0.05 μm and 5 μm PS-MNPs can pass through the placental and mammary barriers, and MNPs accumulating in various organs were size-dependent: the greater the accumulation in organs, the smaller the particle size. Further studies found that the larger 5 μm PS-MPs caused only small accumulation in organs, with the main health hazard being the disruption of intestinal barrier and liver function, indirectly causing gut dysbiosis and metabolic disorders. In contrast, the smaller 0.05 μm PS-NPs caused excessive accumulation in organs, not only impaired the function of the intestine and liver, but also caused direct mechanical damage to physical tissues, and ultimately resulted in more severe intestinal and metabolic disorders. Our findings underline the size-dependent risks associated with micro- and nanoplastics exposure early in life and highlight the necessity for tailored approaches to address health damages from early MNPs exposure.

Phototransformation and toxicity enhancement of silver chloride nanoparticles by polystyrene microplastics under sunlit

Phototransformation and toxicity enhancement of silver chloride nanoparticles by polystyrene microplastics under sunlit

Inhalation of Microplastics Induces Inflammatory Injuries in Multiple Murine Organs via the Toll-like Receptor Pathway.

Previous studies have detected microplastics (MPs) in human biological samples, such as lungs, alveolar lavage fluid, and thrombus. However, whether MPs induce health effects after inhalation are unclear. In this study, fluorescent polystyrene microplastics (PS-MPs) were found in the thymus, spleen, testes, liver, kidneys, and brain on day 1 or day 3 after one intratracheal instillation. Furthermore, mice showed inflammation in multiple organs, manifested as obvious infiltration of neutrophils and macrophages, increased Toll-like receptors (TLRs), myeloid differentiation primary response protein 88 (MyD88) and nuclear factor-κB (NF-κB), as well as proinflammatory cytokines (tumor necrosis factor (TNF)-α and interleukin (IL)-1β) in the lungs, thymus, spleen, liver, and kidneys after four intratracheal instillations of PS-MPs at once every 2 weeks. Hepatic and renal function indexes were also increased. Subsequently, the inflammatory response in multiple murine organs was significantly alleviated by TLR2 and TLR4 inhibitors. Unexpectedly, we did not find any elevated secretion of monocyte chemotactic protein (MCP)-1 or TNF-α by RAW264.7 macrophages in vitro. Thus, PS-MPs induced inflammatory injuries in multiple murine organs via the TLRs/MyD88/NF-κB pathway in vivo, but not macrophages in vitro. These results may provide theoretical support for healthy protection against PS-MPs and their environmental risk assessment.

In Vitro and In Vivo Genotoxicity of Polystyrene Microplastics: Evaluation of a Possible Synergistic Action with Bisphenol A.

The ubiquitous presence of plastics represents a global threat for all ecosystems and human health. In this study, we evaluated, in vitro and in vivo, the genotoxic potential of different concentrations of polystyrene microplastics (PS-MPs) and their possible synergistic interactions with bisphenol-A (BPA). For the in vitro and the in vivo assays, we used human lymphocytes and hemocytes from Lymnaea stagnalis, respectively. The genomic damage was evaluated by the micronucleus assay, and differences in eggs laid and growth of L. stagnalis were also evaluated. In human lymphocytes, PS-MPs alone at the concentration of 200 μg/mL and in association with BPA 0.100 µg/mL significantly increased the frequencies of micronuclei and nuclear buds, indicating a possible in vitro genotoxic additive action of these two compounds. Vice versa, PS-MPs did not result in genotoxicity in hemocytes. Our results indicated that PS-MPs have genotoxic properties only in vitro and at a concentration of 200 µg/mL; moreover, this compound could intensify the genomic damage when tested with BPA, indicating possible cumulative effects. Finally, PS significantly reduced the growth and the number of laid eggs in L. stagnalis.

MRI-based microplastic tracking in vivo and targeted toxicity analysis

Microplastics (MPs) as an emerging pollutant have raised significant concerns in environmental health. However, elucidating the distribution of MPs in living organisms remains challenging due to their trace residue and tough detection problems. In this study, a novel magnetic resonance imaging (MRI)-based tracking method was employed to monitor functionalized MPs biodistribution in vivo. Our results identified that the liver is the primary accumulation site of polystyrene microplastics (PS-MPs) in biological systems through continuous in vivo monitoring spanning 21 days. Biochemical tests were performed to assess the toxicological effects of functionalized MPs on the liver tissue, revealing hepatocyte death, inflammatory cell infiltration, and alterations in alkaline phosphatase levels. Notably, positively charged MPs exhibited more severe effects. A combined metabolomics-proteomics analysis further revealed that PS-MPs interfered with hepatic metabolic pathways, particularly bile secretion and ABC transporters. Overall, this study effectively assessed the distribution of functionalized MPs in vivo utilizing MRI technology, validated toxicity in targeted organ, and conducted an in-depth study on underlying biotoxicity mechanism. These findings offer crucial scientific insights into the potential impact of MPs in the actual environment on human health.

Interfacial interactions between colloidal polystyrene microplastics and Cu in aqueous solution and saturated porous media: Model fitting and mechanism analysis

Microplastic (MP) and heavy metal pollution have received much attention. Few researches have been carried out on the influence of the interaction between MPs and heavy metals on their transport in saturated porous media, which concerns their fate. Therefore, the interaction mechanisms between colloidal polystyrene microplastics (PSMPs) and Cu were first carried out by applying batch adsorption experiments. Subsequently, the transport and retention of PSMPs and Cu in saturated porous media was explored through column experiments. The interaction process between PSMPs and Cu was further investigated using density functional theory (DFT) calculations. Findings demonstrated that PSMPs had strong adsorption capacity for Cu ((60.07 ± 2.57) mg g−1 at pH 7 and ionic strength 0 M) and the adsorption process was chemically dominated, non-uniform, and endothermic. The O-containing functional groups on PSMP surfaces showed essential roles in Cu adsorption, and the adsorption process mainly contained electrostatic and complexation interactions. In column experiments, Cu could inhibit PSMP transport by the cation bridging effect and changing the electrical properties of glass beads, while PSMPs may facilitate Cu transport through the carrying effect. These findings confirmed that interfacial interactions between MPs and Cu could influence their transport in saturated porous media directly, providing great environmental significance.

Removal of sulfamethoxazole using Fe-Mn biochar filtration columns: Influence of co-existing polystyrene microplastics

Emerging contaminants, particularly antibiotics and microplastics (MPs), present significant challenges in wastewater treatment and pose large ecological risks. This study investigates the removal efficiency of sulfamethoxazole (SMX) using Fe-Mn modified biochar (BFM) in fixed bed filtration columns, emphasizing the effect of the presence of polystyrene microplastics (PS-MPs) on SMX behavior in both water (pH ≈ 5.6) and selected wastewater (pH ≈ 8) systems. Batch sorption results show that 10 mg/L SMX in 50 mL water can be completely removed by 100 mg BFM sorbent. The Bed Depth Service Time model indicated the BFM column is feasible for SMX removal in scaled-up continuous wastewater flow operations, while the Yan model best elucidates SMX filtration behavior and suggests the dominant adsorption mechanisms include external mass transfer and intraparticle diffusion. The present of both 20 mg/L and 100 mg/L PS-MPs (pH ≈ 5.6) significantly reduced SMX retention due to competitive sorption. However, at pH 3.2, competitive sorption became negligible due to electrostatic interactions driving the PS-MPs sorption, while neutral charged SMX bound through hydrogen-bonds or π-π EDA interactions. Elevated pH shifted both PS-MPs and SMX sorption to non-electrostatic thus intensifying sorption competition, highlighting the influence of pH on their interaction dynamics. In wastewater, SMX filtration was slightly inhibited by 100 mg/L PS-MPs in BFM columns, whereas PS-MPs removal remained unaffected due to the high ionic strength and alkaline pH. These findings highlight the impact of MPs on pollution removal efficiency in filtration system, essential for enhancing biochar-based wastewater treatment strategies.

Sorption of PFOS onto polystyrene microplastics potentiates synergistic toxic effects during zebrafish embryogenesis and neurodevelopment

Microplastics (MPs) have become an emerging anthropogenic pollutant, and their ability to sorb contaminants potentially enhances the threats to the ecosystem. Only a few studies are available to understand the combined effects of microplastics and other pollutants. The present study investigated the sorption of perfluorooctane sulfonic acid (PFOS) onto polystyrene microplastics (PS-MPs) at varying concentrations, using molecular dynamics simulation (MDS) to preliminarily explore the adsorption behavior. The MDS results revealed negative interaction energies between PFOS and PS-MPs, underscoring PS-MPs' role as a potential adsorbent for PFOS in an aqueous solution. Thereafter, zebrafish embryos were employed to explore the toxic effects of combined exposure to PS-MPs and PFOS. Fluorescence and Scanning Electron Microscopy (SEM) suggested PS-MP accumulation individually and in combination with PFOS on the embryonic chorion membrane. As a result, the exposed group showed increased inner pore size of the chorionic membrane and accelerated heartbeat, indicating hypoxic conditions and hindered gaseous exchange. PS-MPs aggravated the toxicity of PFOS during larval development manifested by delayed hatching rate, increased mortality, and malformation rate. Additionally, increased ROS accumulation and altered antioxidant enzymatic status were observed in all the exposed groups suggesting perturbation of the redox state. Additionally, co-exposure of zebrafish larvae to PS-MPs and PFOS resulted in an abrupt behavioral response, which decreased AChE activity and altered neurotransmitter levels. Taken together, our results emphasize that PS-MPs can act as a potential vector for PFOS, exerting synergistic toxic effects in the aquatic environment, and hence their health risks cannot be ignored.

The effects of microplastics exposure on quail's hypothalamus: Neurotransmission disturbance, cytokine imbalance and ROS/TGF-β/Akt/FoxO3a signaling disruption

Microplastics (MPs) have become a major focus of environmental toxicology, raising concerns about their potential adverse effects on animal organs and body systems. As these tiny particles infiltrate ecosystems, they may pose risks to the health of organisms across diverse species. In this study, we attempted to examine the neurotoxic effects of MPs exposure on avian hypothalamus by using an animal model-Japanese quail (Coturnix japonica). The quails of 7-day-old were exposed to 0.02 mg/kg, 0.4 mg/kg and 8 mg/kg polystyrene microplastic (PS-MPs) of environmental relevance for 35 days. The results showed PS-MPs exposure did damages to hypothalamic structure characterized by neuron malformation, irregular arrangement and cellular vacuolation after 5-week exposure. PS-MPs exposure also induced Nissl body reduction and dissolution in the hypothalamus. Moreover, the decrease of acetylcholinesterase (AchE) activity and increasing acetylcholine (Ach) indicated that PS-MPs exposure caused hypothalamic neurotransmission disturbance. PS-MPs exposure also led to neuroinflammation by disrupting the balance between proinflammatory and anti-inflammatory cytokines. Moreover, increasing reactive oxygen species (ROS) and malondialdehyde (MDA) generation with reducing antioxidants indicated PS-MPs led to hypothalamic oxidative stress. Additionally, RNA-Seq analysis found that both transforming growth factor-β (TGF-β) signaling and forkhead box O (FoxO) signaling were disturbed in the hypothalamus by PS-MPs exposure. Especially, the increasing ROS led to TGF-β activation and then induced hypothalamic inflammation by nuclear factor κB (NF-κB) activation. The present study concluded that oxidative stress might be an important mechanistic signaling involved in MPs neurotoxicology.

Polystyrene microplastics enhanced the photo-degradation and -ammonification of algae-derived dissolved organic matters

Algae-derived organic matter (ADOM) is a key source of chromophoric dissolved organic matter (CDOM) in natural waters. When exposed to solar irradiation, ADOM undergoes gradual degradation and transformation. The escalating presence of microplastics (MPs) can act as a novel type of environmental photosensitizer, however its impacts on ADOM photodegradation remains largely unexplored. Thus, in this study, ADOM were extracted from four common algal species (Microcystis aeruginosa, Synechococcus sp., Chlorella pyrenoidosa and Scenedesmus obliquus) and exposed to UV irradiation with or without polystyrene (PS) MPs, namely ADOM+PS groups and ADOM groups, respectively. The results indicated that a more rapid degradation of amino acid-like substances (∼38 % vs. ∼22 %) and more ammonia products (1.86 vs. 1.21 mg L−1) were observed in the ADOM+PS groups compared to the ADOM groups after a five-day exposure. This enhanced photodegradation might be attributed to the production of environmentally persistent free radicals and reactive species during the photoaging of PS. Furthermore, PS-derived high electron transfer belt activity of ADOM led to the production of highly aromatic and humified products. These humic-like products could potentially accelerate the degradation of amino acid-like compounds by exciting the generation of excited triplet CDOM. This study underscores the role of MPs as environmental photosensitizers in promoting ADOM degradation and ammonia generation, providing insights on the transformation of ADOM mediated by emerging pollutants and its impact on aquatic carbon and nitrogen cycles.

Eco-environmental responses of Eichhornia crassipes rhizobacteria community to co-stress of per(poly)fluoroalkyl substances and microplastics

The stabilization of rhizobacteria communities plays a crucial role in sustaining healthy macrophyte growth. In light of increasing evidence of combined pollution from microplastics (MPs) and per- and polyfluoroalkyl substances (PFASs), Selecting typical floating macrophyte as a case, this study explored their impacts using hydroponic simulations and 16S rRNA high-throughput sequencing. A total of 31 phyla, 77 classes, 172 orders, 237 families, 332 genera, and 125 rhizobacteria species were identified. Proteobacteria (16.19% to 57.70%) was the dominant phylum, followed by Bacteroidota (12.34% to 44.48%) and Firmicutes (11.31% to 36.36%). In terms of α-diversity, polystyrene (PS) MPs and PFASs significantly impacted community abundance (ACE and PD-tree) rather than evenness (Shannon and Pielou) compared to the control. βMNTD and βNTI analyses revealed that PS MPs enhanced deterministic assembly processes driven by F-53B and GenX, while mitigating those induced by PFOA and PFOS. Contamination treatments narrowed the ecological niche breadths at both the phylum (5% (PS) to 49.91% (PS & PFOA)) and genus levels (8% (PS) to 63.96% (PS & PFOA)). Functionally, MPs and PFASs decreased the anaerobic capacity and ammonia nitrogen utilization of rhizosphere bacteria. This study enhances our understanding of the microecological responses of macrophyte-associated bacteria to combined MP and PFAS contamination and offers insights into ecological restoration strategies and mitigating associated environmental risks.

Enhanced removal of polystyrene microplastics by three-dimensional flower-like layered double oxide: Behavior and mechanism insight

Microplastics (MPs) as emerging pollutants are becoming a global threat due to their potential environmental and human health risks. Conventional adsorbents used for MPs elimination tend to be unstable in acid or alkaline conditions, leading to inferior removal efficiency. Herein, a robust and efficient adsorbent, i.e., hierarchically structural ZnAl-layered double oxides (H-ZnAl-LDO), was elaborately developed via a one-step calcination strategy. This process created a flower-like porous structure supported by ZnAl2O4 spinel and ZnO. H-ZnAl-LDO exhibited an outstanding adsorption ability for polystyrene (PS, typical MPs) across a wide pH range (3−11), achieving a removal efficiency of 85–100 % and a maximum adsorption capacity of 91.17 mg/g. The intraparticle diffusion model combined with SEM analysis revealed that pore filling contributed to PS removal. Evidence from in FT-IR and XPS spectra and zeta potential substantiated the PS removal was dominated by electrostatic interaction, hydrogen bonding, and complexation. In addition, given the over 90 % PS removal efficiency from natural water, H-ZnAl-LDO demonstrated high potential in practical applications. This study provides a promising adsorbent for removing microplastics in both acidic and alkaline environments and broadens scope of applications for LDO.

The combined toxicity of polystyrene microplastic and arsenate: From the view of biochemical process in wheat seedlings (Triticum aestivum L.)

Microplastics (MPs) are important carriers of various toxic metals and can alter their toxicity pattern in agricultural soil, leading to combined pollution, therefore posing new challenges to soil pollution management and environmental risk assessment. In this study, we observed the internalization of MPs in plants and conducted incubation experiments to evaluated the effects of arsenate (As(V)) alone and in combination with polystyrene (PS) MPs on wheat seedlings (Triticum aestivum L.). Under As(V) alone and combined with PS-MP exposure, dose-dependent toxicity in terms of root and stem elongation and biomass accumulation was observed. Compared with As(V) alone, the presence of PS-MPs reduced the accumulation of As in wheat roots by 11.43–58.91%, but PS-MPs intensified the transport of As to the aboveground parts of wheat, increasing As accumulation in wheat stems by 27.77–1011.54%. This causes more serious mechanical damage and oxidative stress to plant cells, increasing the accumulation of reactive oxygen species and lipid peroxidation in wheat roots and upregulating the activities of antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD). In addition, the co-exposure of As(V) and PS-MPs disrupts the photosynthetic system of wheat leaves and the secretion activities of roots. Therefore, the combination of As(V) and PS-MPs caused greater damage to wheat growth. Our findings contribute to a more comprehensive assessment of the combined toxicity of MPs and heavy metal to crops.