Reviewing nanoplastic toxicology: It's an interface problem

Gut dysbiosis exacerbates inflammatory liver injury induced by environmentally relevant concentrations of nanoplastics via the gut-liver axis

As an emerging and potentially threatening pollutant, nanoplastics (NPs) have received considerable global attention. Due to their physical properties and diminutive size, NPs ingestion can more easily cross biological barriers and enter the human and animal body. Despite reports of hepatotoxicity associated with NPs, their impact and potential underlying mechanisms remain elusive. In this study, we investigated the impact of NPs at concentrations found in the environment on the gut flora, intestinal barrier function, liver pyroptosis, and inflammation in mice following 12 weeks of exposure. To further validate the involvement of gut flora in inflammatory liver damage caused by NPs, we utilized antibiotics to remove the intestinal flora and performed fecal microbiota transplantation. We confirmed that NPs exposure altered the gut microbiota composition, with a notable rise in the proportions of Alloprevotella and Ileibacterium while causing a decrease in the relative proportions of Dubosiella. This disruption also affected the gut barrier, increasing lipopolysaccharides in circulation and promoting liver pyroptosis. Importantly, mice receiving fecal transplants from NPs-treated mice showed intestinal barrier damage, liver pyroptosis, and inflammation. However, NPs effects on the intestinal barrier and liver pyroptosis were attenuated by antibiotics depletion of the commensal microbiota. In summary, our current research revealed that extended exposure to environmentally relevant concentrations of NPs resulted in inflammatory damage to the liver. Additionally, we have identified for the first time that imbalances in intestinal flora are crucial in liver pyroptosis induced by NPs.

Unveiling the toxicity of micro-nanoplastics: A systematic exploration of understanding environmental and health implications

The surge in plastic production has spurred a global crisis as plastic pollution intensifies, with microplastics and nanoplastics emerging as notable environmental threats. Due to their miniature size, these particles are ubiquitous across ecosystems and pose severe hazards as they are ingested and bioaccumulate within organisms. Although global plastic production has reached an alarming 400.3 MTs, recycling efforts remain limited, with only 18.5 MTs being recycled. Currently, out of the total plastic waste, 49.6 % is converted into energy, 27 % is recycled, and 23.5 % is recovered as material, indicating a need for better waste management practices to combat the escalating pollution levels. Research studies on micro-nanoplastics have primarily concentrated on their environmental presence and laboratory-based toxicity studies. This review critically examines the sources and detection methods for micro-nanoplastics, emphasising their toxicological effects and ecological impacts. Organisms like zebrafish and rats serve as key models for studying these particle's bioaccumulative potential, showcasing adverse effects that extend to DNA damage, oxidative stress, and cellular apoptosis. Studies reveal that micro-nanoplastics can permeate biological barriers, including the blood-brain barrier, neurological imbalance, cardiac, respiratory, and dermatological disorders. These health risks, particularly relevant for humans, underscore the urgency for broader, real-world studies beyond controlled laboratory conditions. Additionally, the review discusses innovative energy-harvesting technologies as sustainable alternatives for plastic waste utilisation, particularly valuable for energy-deficient regions. These strategies aim to simultaneously address energy demands and mitigate plastic waste. This approach aligns with global sustainability goals, providing a promising avenue for both pollution reduction and energy generation. The review calls for further research to enhance detection techniques, assess long-term environmental impacts, and explore sustainable solutions that integrate energy recovery with pollution mitigation, especially in regions most affected by both energy shortages and increased plastic waste.

Acute Exposure to Aerosolized Nanoplastics Modulates Redox-Linked Immune Responses in Human Airway Epithelium

Micro- and nanoplastics (MPs and NPs) are pervasive environmental pollutants detected in aquatic ecosystems, with emerging evidence suggesting their presence in airborne particles generated by water body motion. Inhalation exposure to airborne MPs and NPs remains understudied despite documented links between occupational exposure to these particles and adverse respiratory outcomes, including airway inflammation, oxidative stress, and chronic respiratory diseases. This study explored the effects of acute NP exposure on a fully differentiated 3D human airway epithelial model derived from 14 healthy donors. Airway epithelium was exposed to aerosolized 50 nm polystyrene NPs at concentrations ranging from 2.5 to 2500 µg/mL for three minutes per day over three days. Functional assays revealed no significant alterations in tissue integrity, cell survival, mucociliary clearance, or cilia beat frequency, suggesting intact epithelial function post-exposure. However, cytokine and chemokine profiling identified a significant five-fold increase in CCL3 (MIP-1α), a neutrophilic chemoattractant, in NP-exposed samples compared to controls. This was corroborated by increased neutrophil chemotaxis in response to conditioned media from NP-exposed tissues, indicating a pro-inflammatory neutrophilic response. Conversely, levels of interleukins (IL-21, IL-2, IL-15), CXCL10, and TGF-β were significantly reduced, suggesting immunomodulatory effects that may impair adaptive immune responses and tissue repair mechanisms. These findings demonstrate that short-term exposure to NP-containing aerosols induces a distinct pro-inflammatory response in airway epithelium, characterized by enhanced neutrophil recruitment and reduced secretion of key immune modulators. These findings underscore the potential for aerosolized NPs to induce oxidative and inflammatory stress, raising concerns about their long-term impact on respiratory health and redox regulation.

Microplastic and nanoplastic pollution: Assessing translocation, impact, and mitigation strategies in marine ecosystems

The widespread presence of plastic debris in marine ecosystems was first highlighted as a serious concern in the United Nations Convention on the Law of the Sea (UNCLOS) and the 1972 London Convention. This realization identified plastic pollution as one of the major global environmental issues. Majorities of plastic debris are neither recycled nor incinerated, as a result, it eventually makes its way into lakes, rivers, and oceans. Analysis of water and sediment worldwide indicates that microplastics and nanoplastic are ubiquitous in soils, freshwater, and marine ecosystems. Microplastic and nanoplastics are distributed throughout marine environments via processes such as biofouling and chemical leaching, contaminating both pelagic and benthic species. Despite growing recognition of the hazards posed by microplastics and nanoplastics, regulatory efforts remain hampered by limited understanding of their broader ecological impacts, particularly how diverse factors translate into population declines and ecosystem disruptions. This review examines the pathways of microplastic and nanoplastic pollution, their interactions with other environmental stressors such as climate change and chemical pollution, and their effects on marine food webs. The review highlights the urgent need for further research into the behavior and fate of nanoplastics, which are the degradation product of microplastics, owing to their nano size they pose additional risks, unique properties, and potential for widespread ecological impacts. Studies have demonstrated that smaller microplastics and nanoplastics, particularly nanoplastics, are more toxic than larger microplastics. Additionally, microplastics and nanoplastics serve as vectors for contaminants such as heavy metals, exacerbating their toxicity. They also translocate through marine food chains, posing potential health risks. While evidence of their impact continues to grow, the chronic toxicity of microplastics and nanoplastics remains poorly understood, emphasizing the need for further research, particularly at the cellular level, to fully understand their effects on marine ecosystems and human health. This review also concludes with a call for standardized measurement methods, effective mitigation strategies, and enhanced international cooperation to combat this escalating threat. Future research should prioritize the complex interactions between microplastics and nanoplastics, other pollutants, and marine ecosystems, with the ultimate goal of developing holistic approaches to manage and mitigate the impact of plastic pollution. PRACTITIONER POINTS: Microplastic/nanoplastic translocate through marine food webs, affecting species and human health. Nanoplastics are more toxic than microplastics, exacerbating environmental risks. Nanoplastic aggregation influences their distribution and ecological interactions. Future research should focus on nanoplastic behavior, transport, and toxicity.

The microplastic-crisis: Role of bacteria in fighting microplastic-effects in the digestive system

Plastic particles smaller than 5 mm, referred to as Microplastics, pose health risks, like metabolic, immunological, neurological, reproductive, and carcinogenic effects, after being ingested. Smaller plastic particles are more likely to be absorbed by human cells, with nanoplastics showing higher potential for cellular damage, including DNA fragmentation and altered protein functions. Micro- and nanoplastics (MNPs) affect the gastrointestinal tract by altering the microbial composition, they could influence digestive enzymes, and possibly disrupt mucus layers. In the stomach, they potentially interfere with digestion and barrier functions, while in the intestines, they could increase permeability via inflammation and tissue disruption. MNPs can lead to microbial dysbiosis, leading to gastrointestinal symptoms. By activating inflammatory pathways, altering T cell functions and affecting dendritic cells and macrophages, immune system homeostasis could possibly be disrupted. Probiotics offer potential strategies to alleviate plastic effects, by either degrading plastic particles or directly countering health effects. We compared genetic sequences of probiotics to the genome of known plastic degraders and concluded that no probiotic bacteria could serve the role of plastic degradation. However, probiotics could directly mitigate MNP-health effects. They can restore microbial diversity, enhance the gut barrier, regulate bile acid metabolism, reduce inflammation, regulate insulin balance, and counteract metabolic disruptions. Antioxidative properties protect against lipid peroxidation and MNP-related reproductive system damage. Probiotics can also bind and degrade toxins, like heavy metals and bisphenol A. Additionally, bacteria could be used to aggregate MNPs and reduce their impact. Therefore, probiotics offer a variety of strategies to counter MNP-induced health effects.

Plasma-assisted destruction of polystyrene nanoplastics

This study addresses the critical need for the effective removal of nanoplastics (1 nm to 1000 nm), which pose a significant environmental challenge due to their ease of entry into biological systems and poorly understood health impacts. We report our investigation of a plasma-assisted methodology with a falling film plasma reactor to destroy and remove 200 nm polystyrene nanoplastic particles from their aqueous solution. Using the nanoparticle tracking analysis, size exclusion chromatography, and total organic carbon (TOC) analysis, we examined the degradation kinetics of the nanoplastics upon plasma-assisted treatment. A nanoplastic removal rate of 98.4% by particle count was achieved in one hour of treatment. This rate increased to 99.3% after three hours of treatment, along with a 27.4% reduction in the TOC of the solution. The chromatography results indicate that the observed elimination of nanoplastic contaminants was likely through the production of short polystyrene oligomers with molecular weights roughly equivalent to those of two styrene units. The superior efficacy of the plasma-assisted methodology over traditional ozonation to destroy nanoplastics was also illustrated. Our results not only elucidate a hypothesized polystyrene radical decay mechanism but also demonstrate a potential and complementary approach for mitigating nanoplastic pollution in water purification strategies.

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.

Combined effect of polystyrene nanoparticles and chlorpyrifos to Daphnia magna

Microplastics and nanoplastics (MPs/NPs) are emerging contaminants ubiquitous in the environment. These particles can act as carriers of hydrophobic organic compounds (HOCs), such as chlorpyrifos (CPF), an organophosphorus insecticide. This study investigates the acute toxicity of CPF combined with model polystyrene nanoplastics (PS-NPs) using Daphnia magna as a model organism. The uptake and accumulation of luminescence-labelled 240 nm PS-NPs were visualized and quantified during co-exposure tests. Heart rates were measured using a video-based method, and IC50 values for heart rate were calculated to assess the acute toxicity of CPF. The results demonstrate that PS-NPs alone have no acute toxicity, while CPF exhibits high toxicity, with an IC50 of 50.8 μg/L. However, in the presence of 50 μg/L PS-NPs, the IC50 increased to approximately 400 μg/L, indicating an antagonistic effect of PS-NPs on CPF toxicity. The adsorption of CPF onto PS-NPs can reduce the concentration of free CPF, leading to aggregation and sedimentation of CPF-PS-NP clusters, thereby decreasing the uptake of CPF by D. magna. This interaction between CPF and PS-NPs in D. magna exemplifies the toxicity-attenuating effects and potential load capacity of nanoplastics for HOCs.

Polystyrene nano-plastics impede skeletal muscle development and induce lipid accumulation via the PPARγ/LXRβ pathway in vivo and in vitro in mice

Nano-plastics (NPs) have emerged as a significant environmental pollutant, widely existing in water environment, and pose a serious threat to health and safety with the intake of animals. Skeletal muscle, a vital organ for complex life activities and functional demands, has received limited attention regarding the effects of NPs. In this study, the effects of polystyrene NPs (PS-NPs) on skeletal muscle development were studied by oral administration of different sizes (1 mg/kg) of PS-NPs in mice. The findings revealed that PS-NPs resulted in skeletal muscle damage and significantly hindered muscle differentiation, exhibiting an inverse correlation with PS-NPs particle size. Morphological analysis demonstrated PS-NPs caused partial disruption of muscle fibers, increased spacing between fibers, and lipid accumulation. RT-qPCR and western blots analyses indicated that PS-NPs exposure downregulated the expression of myogenic differentiation-related factors (Myod, Myog and Myh2), activated PPARγ/LXRβ pathway, and upregulated the expressions of lipid differentiation-related factors (SREBP1C, SCD-1, FAS, ACC1, CD36/FAT, ADIPOQ, C/EBPα and UCP-1). In vitro experiments, C2C12 cells were used to confirm cellular penetration of PS-NPs (0, 100, 200, 400 μg/mL) through cell membranes along with activation of PPARγ expression. Furthermore, to verify LXRβ as a key signaling molecule, silencing RNA transfection experiments were conducted, resulting in no increase in the expressions of PPARγ, LXRβ, SREBP1C, FAS, CD36/FAT, ADIPOQ, C/EBPα and UCP-1 even after exposure to PS-NPs. However, the expressions of SCD-1and ACC1 remained unaffected. The present study evidenced that exposure to PS-NPs induced lipid accumulation via the PPARγ/LXRβ pathway thereby influencing skeletal muscle development.

Fibrous microplastics in the environment: Sources, occurrence, impacts, and mitigation strategies

Fibrous microplastics (FMPs), a unique class of microplastics, are increasingly recognized as a significant environmental threat due to their ubiquitous presence and potential risks to ecological and human health. This review provides a comprehensive overview of FMPs, including their sources, prevalence in various environmental media, and potential impacts. FMPs, which can be found in over 90 % of certain environmental samples, originate from a diverse range of sources, including synthetic textiles, landfill waste, industrial emissions, and atmospheric deposition. These persistent pollutants pose a threat to both terrestrial and marine ecosystems. Their insidious presence can lead to ingestion by organisms, potentially disrupting ecosystems and posing risks to human health. Addressing the challenge of FMPs requires a multi-faceted approach. Reducing the production and use of synthetic fibers, implementing effective waste management practices, and developing new technologies to remove FMPs from wastewater and the broader environment are all crucial components of the solution. However, further research is essential to fully understand the long-term implications of FMPs on ecosystems and human health, laying the foundation for the development of robust and effective mitigation strategies.

Magnetic silica-coated cutinase immobilized via ELPs biomimetic mineralization for efficient nano-PET degradation

The proliferation of nano-plastic particles (NPs) poses severe environmental hazards, urgently requiring effective biodegradation methods. Herein, a novel method was developed for degrading nano-PET (polyethylene terephthalate) using immobilized cutinases. Nano-PET particles were prepared using a straightforward method, and biocompatible elastin-like polypeptide-magnetic nanoparticles (ELPs-MNPs) were obtained as magnetic cores via biomimetic mineralization. Using one-pot synthesis with the cost-effective precursor tetraethoxysilane (TEOS), silica-coated magnetically immobilized ELPs-tagged cutinase (ET-C@SiO2@MNPs) were produced. ET-C@SiO2@MNPs showed rapid magnetic separation within 30 s, simplifying recovery and reuse. ET-C@SiO2@MNPs retained 86 % of their initial activity after 11 cycles and exhibited superior hydrolytic capabilities for nano-PET, producing 0.515 mM TPA after 2 h of hydrolysis, which was 96.6 % that of free enzymes. Leveraging ELPs biomimetic mineralization, this approach offers a sustainable and eco-friendly solution for PET-nanoplastic degradation, highlighting the potential of ET-C@SiO2@MNPs in effective nanoplastic waste management and contributing to environmental protection and sustainable development.

A multi-analytical approach to evaluate the removal efficiency of polystyrene nanoparticles in water treatment processes

The removal of nanoplastics (NP) from water using various treatment processes has gained significant attention recently. This study comprehensively characterizes the degradation of polystyrene nanoparticles (concentration: 200 ppm, diameter: 140 nm) through UVC irradiation. For the first time, we compared four analytical methods to monitor removal efficiency: Py-GCMS, UV-Visible spectroscopy, TOC, and Turbidity. Additionally, DLS, TEM, and SEC were used to understand changes in particle size, morphology, and molecular weight. Results showed that Py-GCMS overestimated the removal rate by a factor of 2 compared to Turbidity and UV-Visible measurements, which were in agreement. Furthermore, after 200 h of irradiation, the styrene signal disappears from the pyrogram, although the mineralization rate reaches only 50%, as determined by total organic carbon (TOC) analysis. The particle size decreased slowly, reaching 100 nm after 150 h, while a significant decrease in molecular weight indicated high chain-scission. These findings emphasize the importance of a multi-analytical approach to accurately assess NP removal efficiency and understand degradation mechanisms.

Exacerbated interfacial impacts of nanoplastics and 6:2 chlorinated polyfluorinated ether sulfonate by natural organic matter in adult zebrafish: Evidence through histopathology, gut microbiota, and transcriptomic analysis

Nanoplastics (NPs) interact with cooccurring chemicals and natural organic matter (NOM) in the environment, forming complexes that can change their bioavailability and interfacial toxicity in aquatic organisms. This study aims to elucidate the single and combined impacts of 21-day chronic exposure to low levels of polystyrene NPs (size 80 nm) at 1 mg/L and 6:2 chlorinated polyfluorinated ether sulfonate (Cl-PFAES or F53B) at 200 μg/L in the presence and absence of NOM (humic acid-HA and bovine serum albumin-BSA at 10 mg/L) in adult zebrafish (Danio rerio). Our findings through multiple bioassays, revealed that the mixture group (M), comprising of NPs, F53B, HA, and BSA, caused a higher level of toxicity compared to the single NPs (AN), single F53B (AF), and combined NPs+F53B (ANF) groups. The mixture exposure caused the highest level of vacuolization and nuclear condensation in hepatocytes, and most of the intestinal villi were fused and highly reduced in villi length and crypt depth. Further, the T-AOC levels were significantly lower (p < 0.05), while the MDA levels in the liver and intestine were significantly higher (p < 0.05) in the M group with downregulation of nfkbiaa, while upregulation of prkcda, csf1ra, and il1b apoptosis genes in the liver. Pairwise comparison of gut microbiota showed significantly higher (p < 0.05) abundances of various genera in the M group, including Gordonia, Methylobacterium, Tundrisphaera, GKS98, Pedomicrobium, Clostridium, Candidatus and Anaerobacillus, as well as higher abundance of genera including pathogenic strains, while control group showed higher abundance of probiotic genus ZOR0006 than exposed group (p < 0.01). The transcriptomic analysis revealed highest number of DEGs in the M group (2815), followed by the AN group (506) and ANF group (206) with the activation of relaxin signaling pathway-RSP (slc9a1, slc9a2) and AMP-activated protein kinase (AMPK) pathway (plin1), and suppression of the toll-like receptor (TLR) pathway (tlr4a, tlr2, tlr1), cytokine-cytokine receptor interaction (CCRI) pathway (tnfb, il21r1, il21, ifng1), and peroxisome proliferator-activated receptors (PPAR) pathway (pfkfb3). Overall, toxicity in the M group was higher, indicating that the HA and BSA elevated the interfacial impacts of NPs and F53B in adult zebrafish after chronic environmentally relevant exposure, implying the revisitation of the critical interaction of NOM with co-occurring chemicals and associated impacts.

Environmental nanoplastics quantification by pyrolysis-gas chromatography-mass spectrometry in the Pearl River, China: First insights into spatiotemporal distributions, compositions, sources and risks

Nanoplastics (NPs, size <1000 nm) are ubiquitous plastic particles, potentially more abundant than microplastics in the environment; however, studies highlighting their distribution dynamics in freshwater are rare due to analytical limitations. Here, we investigated spatiotemporal levels of nine polymers of NPs in surface water samples (n = 30) from the full stretch of the Pearl River (sites, n = 15) using pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). Six polymers were detected, including polystyrene (PS), polyvinyl chloride (PVC), nylon/polyamide 66 (PA66), polyester (PES), poly(methyl methacrylate) (PMMA) and polyethylene (PE), where three polymers showed high detection frequencies; PS (100 % in winter and summer), followed by PVC (73 % in winter and 87 % in summer) and PA66 (53 % in winter and 67 % in summer). The spatiotemporal distribution revealed the sites related to aquaculture (AQ) and shipping (SHP) showed higher NP levels than those of human settlement (HS) and wastewater treatment plants (WWTPs) (p = 0.004), and relatively high average levels of NPs in the urban sites compared to rural sites (p = 0.04), albeit showed no obvious seasonal differences (p = 0.78). For instance, the average PS levels in the Pearl River were in the following order: AQ 411.55 µg/L > SHP 81.75 µg/L > WWTP 56.66 µg/L > HS 47.75 µg/L in summer and HS 188.1 µg/L > SHP 103.55 µg/L > AQ 74.7 µg/L > WWTP 62.1 µg/L in winter. Source apportionment showed a higher contribution through domestic plastic waste emissions among urban sites, while rural sites showed an elevated contribution via aquaculture, agriculture, and surface run-off to the NP pollution. Risk assessment revealed that NPs at SHP and AQ sites posed a higher integrated risk in terms of pollution load index (PLI) than those at WWTP and HS sites. Regarding polymer hazard index (HI), 80 % of sampling sites in summer and 60 % of sampling sites in winter posed level III polymer risk, with PVC posing the highest risk. This study provides novel insights into the seasonal contamination and polymer risks of NP in the Pearl River, which will help to regulate the production and consumption of plastics in the region. ENVIRONMENTAL IMPLICATIONS: The contamination dynamics of field nanoplastics (NPs) in freshwater resources remain little understood, mainly attributed to analytical constraints. This study aims to highlight the spatiotemporal distribution of NPs in the Pearl River among various land use types, urban-rural comparison, seasonal comparison, their compositional profiles, potential sources, interaction with environmental factors, and ecological and polymer hazard assessments of investigated polymers in the full stretch of the Pearl River from Liuxi Reservoir to the Pearl River Delta (PRD) region. This study, with a comparatively large number of samples and NP polymers, will offer novel insights into the contamination profiles of nano-sized plastic particles in one of the important freshwater riverine systems in China.

Orally Ingested Micro- and Nano-Plastics: A Hidden Driver of Inflammatory Bowel Disease and Colorectal Cancer

Micro- and nano-plastics (MNPLs) can move along the food chain to higher-level organisms including humans. Three significant routes for MNPLs have been reported: ingestion, inhalation, and dermal contact. Accumulating evidence supports the intestinal toxicity of ingested MNPLs and their role as drivers for increased incidence of colorectal cancer (CRC) in high-risk populations such as inflammatory bowel disease (IBD) patients. However, the mechanisms are largely unknown. In this review, by using the leading scientific publication databases (Web of Science, Google Scholar, Scopus, PubMed, and ScienceDirect), we explored the possible effects and related mechanisms of MNPL exposure on the gut epithelium in healthy conditions and IBD patients. The summarized evidence supports the idea that oral MNPL exposure may contribute to intestinal epithelial damage, thus promoting and sustaining the chronic development of intestinal inflammation, mainly in high-risk populations such as IBD patients. Colonic mucus layer disruption may further facilitate MNPL passage into the bloodstream, thus contributing to the toxic effects of MNPLs on different organ systems and platelet activation, which may, in turn, contribute to the chronic development of inflammation and CRC development. Further exploration of this threat to human health is warranted to reduce potential adverse effects and CRC risk.

Differences of microplastics and nanoplastics in urban waters: Environmental behaviors, hazards, and removal

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in the aquatic environment and have caused widespread concerns globally due to their potential hazards to humans. Especially, NPs have smaller sizes and higher penetrability, and therefore can penetrate the human barrier more easily and may pose potentially higher risks than MPs. Currently, most reviews have overlooked the differences between MPs and NPs and conflated them in the discussions. This review compared the differences in physicochemical properties and environmental behaviors of MPs and NPs. Commonly used techniques for removing MPs and NPs currently employed by wastewater treatment plants and drinking water treatment plants were summarized, and their weaknesses were analyzed. We further comprehensively reviewed the latest technological advances (e.g., emerging coagulants, new filters, novel membrane materials, photocatalysis, Fenton, ozone, and persulfate oxidation) for the separation and degradation of MPs and NPs. Microplastics are more easily removed than NPs through separation processes, while NPs are more easily degraded than MPs through advanced oxidation processes. The operational parameters, efficiency, and potential governing mechanisms of various technologies as well as their advantages and disadvantages were also analyzed in detail. Appropriate technology should be selected based on environmental conditions and plastic size and type. Finally, current challenges and prospects in the detection, toxicity assessment, and removal of MPs and NPs were proposed. This review intends to clarify the differences between MPs and NPs and provide guidance for removing MPs and NPs from urban water systems.

The Impact of Virgin and Aged Microstructured Plastics on Proteins: The Case of Hemoglobin Adsorption and Oxygenation

Plastic particles, particularly micro- and nanoparticles, are emerging pollutants due to the ever-growing amount of plastics produced across a wide variety of sectors. When plastic particles enter a biological medium, they become surrounded by a corona, giving them their biological identity and determining their interactions in the living environment and their biological effects. Here, we studied the interactions of microstructured plastics with hemoglobin (Hb). Virgin polyethylene microparticles (PEMPs) and polypropylene microparticles (PPMPs) as well as heat- or irradiation-aged microparticles (ag-PEMPs and ag-PPMPs) were used to quantify Hb adsorption. Polypropylene filters (PP-filters) were used to measure the oxygenation of adsorbed Hb. Microstructured plastics were characterized using optical microscopy, SAXS, ATR-FTIR, XPS, and Raman spectroscopy. Adsorption isotherms showed that the Hb corona thickness is larger on PPMPs than on PEMPs and Hb has a higher affinity for PPMPs than for PEMPs. Hb had a lower affinity for ag-PEMPs and ag-PPMPs, but they can be adsorbed in larger amounts. The presence of partial charges on the plastic surface and the oxidation rate of microplastics may explain these differences. Tonometry experiments using an original method, the diffuse reflection of light, showed that adsorbed Hb on PP-filters retains its cooperativity, but its affinity for O2 decreases significantly.

Generation and Fate of Nanoplastics in the Intestine of Plastic-Degrading Insect (Tenebrio molitor Larvae) during Polystyrene Microplastic Biodegradation

The insect Tenebrio molitor exhibits ultrafast efficiency in biodegrading polystyrene (PS). However, the generation and fate of nanoplastics (NPs) in the intestine during plastic biodegradation remain unknown. In this study, we investigated the biodegradation of PS microplastics (MPs) mediated by T. molitor larvae over a 4-week period and confirmed biodegradation by analyzing Δδ13C in the PS before and after biotreatment (-28.37‰ versus -24.88‰) as an effective tool. The ·OH radicals, primarily contributed by gut microbiota, and H2O2, primarily produced by the host, both increased after MP digestion. The size distribution of residual MP particles in excrements fluctuated within the micrometer ranges. PS NPs were detected in the intestine but not in the excrements. At the end of Weeks 1, 2, 3, and 4, the concentrations of PS NPs in gut tissues were 3.778, 2.505, 2.087, and 2.853 ng/lava, respectively, while PS NPs in glands were quantified at 0.636, 0.284, and 0.113 ng/lava and eventually fell below the detection limit. The PS NPs in glands remained below the detection limit at the end of Weeks 5 and 6. This indicates that initially, NPs generated in the gut entered glands, then declined gradually and eventually disappeared or possibly biodegraded after Week 4, associated with the elevated plastic-degrading capacities of T. molitor larvae. Our findings unveil rapid synergistic MP biodegradation by the larval host and gut microbiota, as well as the fate of generated NPs, providing new insights into the risks and fate associated with NPs during invertebrate-mediated plastic biodegradation.

Molecular insights into nanoplastics-peptides binding and their interactions with the lipid membrane

Micro- and nanoplastics have become a significant concern, due to their ubiquitous presence in the environment. These particles can be internalized by the human body through ingestion, inhalation, or dermal contact, and then they can interact with environmental or biological molecules, such as proteins, resulting in the formation of the protein corona. However, information on the role of protein corona in the human body is still missing. Coarse-grain models of the nanoplastics and pentapeptides were created and simulated at the microscale to study the role of protein corona. Additionally, a lipid bilayer coarse-grain model was reproduced to investigate the behavior of the coronated nanoplastics in proximity of a lipid bilayer. Hydrophobic and aromatic amino acids have a high tendency to create stable bonds with all nanoplastics. Moreover, polystyrene and polypropylene establish bonds with polar and charged amino acids. When the coronated nanoplastics are close to a lipid bilayer, different behaviors can be observed. Polyethylene creates a single polymeric chain, while polypropylene tends to break down into its single chains. Polystyrene can both separate into its individual chains and remain aggregated. The protein corona plays an important role when interacting with the nanoplastics and the lipid membrane. More studies are needed to validate the results and to enhance the complexity of the systems.

Polystyrene nanoplastic and engine oil synergistically intensify toxicity in Nile tilapia, Oreochromis niloticus : Polystyrene nanoplastic and engine oil toxicity in Nile tilapia

Polystyrene nanoplastic (PS-NPs) and Engine oil (EO) pose multiple ecotoxic effects with increasing threat to fish ecosystems. The current study investigated the toxicity of 15 days exposure to PS-NPs and / or EO to explore their combined synergistic effects on Nile tilapia, Oreochromis niloticus (O. niloticus). Hematobiochemical parameters, proinflammatory cytokines, and oxidative stress biomarkers as well as histological alterations were evaluated. The experimental design contained 120 acclimated Nile tilapia distributed into four groups, control, PS-NPs (5 mg/L), EO (1%) and their combination (PS-NPs + EO). After 15-days of exposure, blood and tissue samples were collected from all fish experimental groups. Results indicated that Nile tilapia exposed to PS-NPs and / or EO revealed a significant decrease in almost all the measured hematological parameters in comparison to the control, whereas WBCs and lymphocyte counts were significantly increased in the combined group only. Results clarified that the combined PS-NPs + EO group showed the maximum decrease in RBCs, Hb, MCH and MCHC, and showed the maximum significant rise in interleukin-1β (IL-1β), and interleukin-6 (IL-6) in comparison to all other exposed groups. Meanwhile, total antioxidant capacity (TAC) showed a significant (p < 0.05) decline only in the combination group, whereas reduced glutathione (GSH) showed a significant decline in all exposed groups in comparison to the control. Both malondialdehyde (MDA) and aspartate aminotransferase (AST) showed a significant elevation only in the combination group. Uric acid showed the maximum elevation in the combination group than all other groups, whereas creatinine showed significant elevation in the EO and combination group when compared to the control. Furthermore, the present experiment proved that exposure to these toxicants either individually or in combination is accompanied by pronounced histomorpholgical damage characterized by severe necrosis and hemorrhage of the vital organs of Nile tilapia, additionally extensively inflammatory conditions with leucocytes infiltration. We concluded that combination exposure to both PS-NPs and EO caused severe anemia, extreme inflammatory response, oxidative stress, and lipid peroxidation effects, thus they can synergize with each other to intensify toxicity in fish.

Molecular modeling of the carbohydrate corona formation on a polyvinyl chloride nanoparticle and its impact on the adhesion to lipid bilayers

The pervasive presence of nanoplastics (NPs) in the environment has gained increasing attention due to their accumulation in living organisms. These emerging contaminants inevitably interact with extracellular polymeric substances along respiratory or gastrointestinal tracts, and diverse organic coating on the surface of NPs, known as bio- or eco-corona, is formed. Although its impact on altering the NP properties and potential cell internalization has been extensively examined, studies on its role in NP partitioning in the cell membrane are elusive yet. In this work, molecular dynamics is used to investigate the formation of chitosan (CT) corona centered on a polyvinyl chloride (PVC) nanoparticle and the uptake of the resulting complex onto lipid membranes. Coarse-grained models compatible with the newly developed Martini 3.0 force field are implemented for the two polymers employing the atomistic properties as targets in the parameterization. The reliability of the coarse-grained polymer models is demonstrated by reproducing the structural properties of the PVC melt and of solvated CT strands, as well as by determining the conformation adopted by the latter at the NP surface. Results show that the spontaneous binding of CT chains of high and intermediate protonation degrees led to the formation of soft and hard corona that modulates the interaction of PVC core with model membranes. The structural changes of the corona adsorbed at the lipid-water interface enable a subsequent transfer of the NP to the center of the saturated lipid membranes and a complete or partial transition to a snorkel conformation depending on the hydrophilic/hydrophobic balance in the CT-PVC complex. Overall, the computational investigation of the coarse-grained model system provides implications for understanding how the eco-corona development influences the uptake and implicit toxicology of NPs.

Polystyrene microplastics interaction and influence on the growth kinetics and metabolism of tilapia gut probiotic Bacillus tropicus ACS1

Gut probiotic bacteria play a significant role in the host health, immunity, and survival. In aquaculture, changes in the gut microbiome of fishes affect the overall productivity and product quality. In the scenario of growing plastic pollution and associated microplastic prevalence, the current study was designed to investigate the interactions and impact of prepared polystyrene microplastics (PS-MPs) of irregular surface morphology on a probiotic bacteria Bacillus tropicus ACS1, isolated from the gut of Oreochromis mossambicus (commonly called as Tilapia). The cell viability was significantly increased along with changes in bacterial growth kinetics upon exposure to varying concentrations of PS-MPs. The microplastic exposure also increased the production of exopolysaccharides (EPS) and induced slight changes in the IR spectra of the EPS. A peak representing a carbonyl linkage that could be attributed to the glycosidic linkages between sugars disappeared following exposure to higher concentrations of PS-MPs. The interaction between the bacteria and the microplastics was visualized using scanning electron microscopy (SEM) and the colonization of the bacteria with active biofilm formation was observed. The investigation of PS-MP induced oxidative stress in the bacteria revealed the generation of reactive oxygen species (ROS) and increase in anti-oxidant enzyme concentrations, superoxide dismutase (SOD), and catalase. The study provides new insights into the effect of microplastics on gut probiotics of an economically significant aquaculture species.

Mechanistic Insights into Cellular and Molecular Basis of Protein-Nanoplastic Interactions

Plastic waste is ubiquitously present across the world, and its nano/sub-micron analogues (plastic nanoparticles, PNPs), raise severe environmental concerns affecting organisms' health. Considering the direct and indirect toxic implications of PNPs, their biological impacts are actively being studied; lately, with special emphasis on cellular and molecular mechanistic intricacies. Combinatorial OMICS studies identified proteins as major regulators of PNP mediated cellular toxicity via activation of oxidative enzymes and generation of ROS. Alteration of protein function by PNPs results in DNA damage, organellar dysfunction, and autophagy, thus resulting in inflammation/cell death. The molecular mechanistic basis of these cellular toxic endeavors is fine-tuned at the level of structural alterations in proteins of physiological relevance. Detailed biophysical studies on such protein-PNP interactions evidenced prominent modifications in their structural architecture and conformational energy landscape. Another essential aspect of the protein-PNP interactions includes bioenzymatic plastic degradation perspective, as the interactive units of plastics are essentially nano-sized. Combining all these attributes of protein-PNP interactions, the current review comprehensively documented the contemporary understanding of the concerned interactions in the light of cellular, molecular, kinetic/thermodynamic details. Additionally, the applicatory, economical facet of these interactions, PNP biogeochemical cycle and enzymatic advances pertaining to plastic degradation has also been discussed.

The potential impacts of micro-and-nano plastics on various organ systems in humans

Humans are exposed to micro-and-nano plastics (MNPs) through various routes, but the adverse health effects of MNPs on different organ systems are not yet fully understood. This review aims to provide an overview of the potential impacts of MNPs on various organ systems and identify knowledge gaps in current research. The summarized results suggest that exposure to MNPs can lead to health effects through oxidative stress, inflammation, immune dysfunction, altered biochemical and energy metabolism, impaired cell proliferation, disrupted microbial metabolic pathways, abnormal organ development, and carcinogenicity. There is limited human data on the health effects of MNPs, despite evidence from animal and cellular studies. Most of the published research has focused on specific types of MNPs to assess their toxicity, while other types of plastic particles commonly found in the environment remain unstudied. Future studies should investigate MNPs exposure by considering realistic concentrations, dose-dependent effects, individual susceptibility, and confounding factors.

Biodegradation of microplastics: Advancement in the strategic approaches towards prevention of its accumulation and harmful effects

Microplastics (MPs) are plastic particles in a size ranging from 1 mm to 5 mm in diameter, and are formed by the breakdown of plastics from different sources. They are emerging environmental pollutants, and pose a great threat to living organisms. Improper disposal, inadequate recycling, and excessive use of plastic led to the accumulation of MP in the environment. The degradation of MP can be done either biotically or abiotically. In view of that, this article discusses the molecular mechanisms that involve bacteria, fungi, and enzymes to degrade the MP polymers as the primary objective. As per as abiotic degradation is concerned, two different modes of MP degradation were discussed in order to justify the effectiveness of biotic degradation. Finally, this review is concluded with the challenges and future perspectives of MP biodegradation based on the existing research gaps. The main objective of this article is to provide the readers with clear insight, and ideas about the recent advancements in MP biodegradation.

Exposure sources and pathways of micro- and nanoplastics in the environment, with emphasis on potential effects in humans: A systematic review

Microplastics (MPs) are emerging pollutants that are ubiquitous in the environment, and may be a potential threat to human health. This review describes the MP exposure sources and pathways through drinking water, food intake, and air inhalation. The unregulated discharge of MPs in water sources and the absence of required MP filter technology in water treatment plants are important routes of MP exposure through drinking water. The presence of MPs in food may lead to the accumulation of MPs in the body. Exposure to MPs can occur through airborne fallout and dust inhalation in both indoor and outdoor environments. This review summarizes the MP exposure sources and possible pathways in the human body, and illustrates that the intake of drinking water, food consumption, and air inhalation should be assessed in during routine activities. Integr Environ Assess Manag 2023;19:1422-1432. © 2023 SETAC.

Sodium nitroprusside alleviates nanoplastics-induced developmental toxicity by suppressing apoptosis, ferroptosis and inflammation

The health damage caused by nanoplastics (NPs) pollution has become one of the global scientific problems to be solved urgently. However, the toxicological mechanism of NPs is complex, and the research progress of anti-toxicity is limited. Thus, it has potential application value to explore or develop drugs that can effectively alleviate or remove NPs with biological toxicity. In this research, 8 μM sodium nitroprusside (SNP) solution was used to treat zebrafish larvae with 20 mg/L NPs for up to 12 days, and the results showed that SNP treatments were effective in alleviating NPs-caused developmental toxicity in zebrafish larvae. Further examination of its signaling pathway revealed that NPs-induced oxidative stress was mitigated by activating the NO-sGC-cGMP signaling pathway and reduced most of the reactive oxygen species (ROS). Subsequently, we detected the key substances and the key enzymes involved in apoptosis and ferroptosis, and found that oxidative stress-induced mitochondria-dependent apoptosis and lipid peroxidation-caused ferroptosis were alleviated. Finally, observed the accumulation of NPs and ROS in the liver of zebrafish larvae, which is the target organ of immunotoxicity, and we found that SNP could alleviate NPs-caused inflammation by analyzing the fluorescence intensity of neutrophils and macrophages in transgenic zebrafish and detecting the expression of key immune genes. In conclusion, this research has shown for the first time that SNP treatment can significantly inhibit NPs-induced developmental toxicity, resulting from oxidative stress-induced apoptosis, ferroptosis and inflammation in zebrafish larvae.

Biological interactions of polystyrene nanoplastics: Their cytotoxic and immunotoxic effects on the hepatic and enteric systems

As emerging pollutants in the environment, nanoplastics (NPs) can cross biological barriers and be enriched in organisms, posing a greatest threat to the health of livestock and humans. However, the size-dependent toxic effects of NPs in higher mammals remain largely unknown. To determine the size-dependent potential toxicities of NPs, we exposed mouse (AML-12) and human (L02) liver cell lines in vitro, and 6-week-old C57BL/6 mice (well-known preclinical model) in vivo to five different sizes of polystyrene NPs (PS-NPs) (20, 50, 100, 200 and 500 nm). We found that ultra-small NPs (20 nm) induced the highest cytotoxicity in mouse and human liver cell lines, causing oxidative stress and mitochondrial membrane potential loss on AML-12 cells. Unexpectedly in vivo, after long-term oral exposure to PS-NPs (75 mg/kg), medium NPs (200 nm) and large NPs (500 nm) induced significant hepatotoxicity, evidenced by increased oxidative stress, liver dysfunction, and lipid metabolism disorders. Most importantly, medium or large NPs generated local immunotoxic effects via recruiting and activating more numbers of neutrophils and monocytes in the liver or intestine, which potentially resulted in increased proinflammatory cytokine secretion and the tissue damage. The discrepancy in in vitro-in vivo toxic results might be attributed to the different properties of biodistribution and tissue accumulation of different sized NPs in vivo. Our study provides new insights regarding the hepatotoxicity and immunotoxicity of NPs on human and livestock health, warranting us to take immense measures to prevent these NPs-associated health damage.

Folate-receptor-targeted co-self-assembly carrier-free gemcitabine nanoparticles loading indocyanine green for chemo-photothermal therapy

The carrier-free chemo-photothermal therapy has become a promising strategy to improve anti-cancer therapeutic efficacy owing to the combination of chemotherapy and photothermal therapy, with improved chemotherapy drug pharmacodynamics and pharmacokinetics, high drug loading, and reduced toxicity. We designed a novel carrier-free targeting nanoparticles, co-self-assembled amphiphilic prodrugs 3',5'-dioleoyl gemcitabine (DOG), and tumor-targeted γ-octadecyl folate (MOFA), with encapsulated US Food and Drug Administration (FDA)-approved photosensitizer indocyanine green (ICG) for synergistic chemo-photothermal therapy. The DOG linking oleic acid to the sugar moiety of gemcitabine (GEM) showed better self-assembly ability among GEM amphiphilic prodrugs linking different fatty acids. The readily available and highly reproducible 3',5'-dioleoyl gemcitabine/γ-octadecyl folate/indocyanine green (DOG/MOFA/ICG) nanoparticles were prepared by reprecipitation and showed nano-scale structure with mono-dispersity, great encapsulation efficiency of ICG (approximately 74%), acid- and laser irradiation-triggered GEM release in vitro and sustained GEM release in vivo after intravenous administration as well as excellent temperature conversion (57.0°C) with near-infrared laser irradiation. The combinational DOG/MOFA/ICG nanoparticles with near-infrared laser irradiation showed better anti-tumor efficacy than individual chemotherapy or photothermal therapy, with very low hemolysis and inappreciable toxicity for L929 cells. This co-self-assembly of the ICG and the chemotherapy drug (GEM) provides a novel tactic for the rational design of multifunctional nanosystems for targeting drug delivery and theranostics.

Polystyrene nanoplastics in the marine mussel Mytilus galloprovincialis

Concerns about plastic pollution and its toxicity towards animals and people are growing. Polystyrene (PS) is a plastic polymer highly produced in Europe for packaging purposes and building insulation amongst others. Whatever their source-illegal dumping, improper waste management, or a lack of treatment for the removal of plastic debris from wastewater treatment plants-PS products ultimately end up in the marine environment. Nanoplastics (<1000 nm) are the new focus for plastic pollution, gaining broad interest. Whether primary or secondary, their small size permits nanoparticles to cross cellular boundaries, consequently leading to adverse toxic effects. An in vitro assay of Mytilus galloprovincialis haemocytes exposed to 10 μg/L of polystyrene nanoplastics (PS-NPs; 50 nm) for 24 h was used to test cellular viability along with the luminescence inhibition (LC50) of Aliivibrio fischeri bacteria to evaluate acute toxicity. Cellular viability of mussel haemocytes decreased significantly after a 24 h exposure and PS-NPs LC50 range from 180 to 217, μg/L. In addition, a 28-day exposure of the marine bivalve M. galloprovincialis to PS-NPs (10 μg/L; 50 nm) was performed to evaluate the neurotoxic effects and the uptake of these plastic particles in three bivalve tissues (gills, digestive gland, and gonads). The ingestion of PS-NPs was time- and tissue-specific, suggesting that PS-NPs are ingested through the gills and then translocated through the mussel bloodstream, to the digestive gland and gonads where the highest amount of ingested PS-NPs was reported. Ingested PS-NPs may compromise the digestive glands' key metabolic function and impair mussels' gametogenic and reproductive success. Data on acetylcholinesterase inhibition and those previously obtained on a wide range of cellular biomarkers were elaborated through weighted criteria providing a synthetic assessment of cellular hazard from PS-NPs.

Advantages and Potential Benefits of Using Organoids in Nanotoxicology

Organoids are microtissues that recapitulate the complex structural organization and functions of tissues and organs. Nanoparticles have several specific properties that must be considered when replacing animal models with in vitro studies, such as the formation of a protein corona, accumulation, ability to overcome tissue barriers, and different severities of toxic effects in different cell types. An increase in the number of articles on toxicology research using organoid models is related to an increase in publications on organoids in general but is not related to toxicology-based publications. We demonstrate how the quantitative assessment of toxic changes in the structure of organoids and the state of their cell collections provide more valuable results for toxicological research and provide examples of research methods. The impact of the tested materials on organoids and their differences are also discussed. In conclusion, we highlight the main challenges, the solution of which will allow researchers to approach the replacement of in vivo research with in vitro research: biobanking and standardization of the structural characterization of organoids, and the development of effective screening imaging techniques for 3D organoid cell organization.

Transgenerational impacts of micro(nano)plastics in the aquatic and terrestrial environment

Plastic particles of diameters ranging from 1 to 1000 nm and > 1 µm to 5 mm are respectively known as nanoplastics and microplastics, and are collectively termed micro(nano)plastics (MNPs). They are ubiquitously present in aquatic and terrestrial environments, posing adverse multifaceted ecological impacts. Recent transgenerational studies have demonstrated that MNPs negatively impact both the exposed parents and their unexposed generations. Therefore, this review summarizes the available research on the transgenerational impacts of MNPs in aquatic and terrestrial organisms, induced by exposure to MNPs alone or in combination with other organic and inorganic chemicals. The most commonly reported transgenerational effects of MNPs include tissue bioaccumulation and transfer, affecting organisms' survival, growth, reproduction, and energy metabolism; inducing oxidative stress; enzyme and genetic responses; and causing tissue damage. Similarly, co-exposure to MNPs and chemicals (organic and inorganic pollutants) significantly impacts survival, growth, and reproduction and induces oxidative stress, thyroid disruption, and genetic toxicity in organisms. The characteristics of MNPs (degree of aging, size, shape, polymer type, and concentration), exposure type and duration (parental exposure vs. multigenerational exposure and acute exposure vs. chronic exposure), and MNP-chemical interactions are the main factors affecting transgenerational impacts. Selecting MNP properties based on their realistic environmental behavior, employing more diverse animal models, and considering chronic exposure and MNP-chemical mixture exposure are salient research prospects for an in-depth understanding of the transgenerational impacts of MNPs.

Nanoplastics in the soil environment: Analytical methods, occurrence, fate and ecological implications

Soils play a very important role in ecosystems sustainability, either natural or agricultural ones, serving as an essential support for living organisms of different kinds. However, in the current context of extremely high plastic pollution, soils are highly threatened. Plastics can change the chemical and physical properties of the soils and may also affect the biota. Of particular importance is the fact that plastics can be fragmented into microplastics and, to a final extent into nanoplastics. Due to their extremely low size and high surface area, nanoplastics may even have a higher impact in soil ecosystems. Their transport through the edaphic environment is regulated by the physicochemical properties of the soil and plastic particles themselves, anthropic activities and biota interactions. Their degradation in soils is associated with a series of mechanical, photo-, thermo-, and bio-mediated transformations eventually conducive to their mineralisation. Their tiny size is precisely the main setback when it comes to sampling soils and subsequent processes for their identification and quantification, albeit pyrolysis coupled with gas chromatography-mass spectrometry and other spectroscopic techniques have proven to be useful for their analysis. Another issue as a consequence of their minuscule size lies in their uptake by plants roots and their ingestion by soil dwelling fauna, producing morphological deformations, damage to organs and physiological malfunctions, as well as the risks associated to their entrance in the food chain, although current conclusions are not always consistent and show the same pattern of effects. Thus, given the omnipresence and seriousness of the plastic menace, this review article pretends to provide a general overview of the most recent data available regarding nanoplastics determination, occurrence, fate and effects in soils, with special emphasis on their ecological implications.

In Silico Analysis of Nanoplastics' and β-amyloid Fibrils' Interactions

Plastic pollution has become a global environmental threat, which leads to an increasing concern over the consequences of plastic exposition on global health. Plastic nanoparticles have been shown to influence the folding of proteins and influence the formation of aberrant amyloid proteins, therefore potentially triggering the development of systemic and local amyloidosis. This work aims to study the interaction between nanoplastics and β-amyloid fibrils to better understand the potential role of nanoplastics in the outbreak of neurodegenerative disorders. Using microsecond-long coarse-grained molecular dynamics simulations, we investigated the interactions between neutral and charged nanoparticles made of the most common plastic materials (i.e., polyethylene, polypropylene, and polystyrene) and β-amyloid fibrils. We observe that the occurrence of contacts, region of amyloid fibril involved, and specific amino acids mediating the interaction depend on the type and charge of the nanoparticles.

Plants oxidative response to nanoplastic

Pollution of the environment with plastic is an important concern of the modern world. It is estimated that annually over 350 million tonnes of this material are produced, wherein, despite the recycling methods, a significant part is deposited in the environment. The plastic has been detected in the industrial areas, as well as farmlands and gardens in many world regions. Larger plastic pieces degraded in time into smaller pieces including microplastic (MP) and nanoplastic particles (NP). Nanoplastic is suggested to pose the most serious danger as due to the small size, it is effectively taken up from the environment by the biota and transported within the organisms. An increasing number of reports show that NP exert toxic effects also on plants. One of the most common plant response to abiotic stress factors is the accumulation of reactive oxygen species (ROS). On the one hand, these molecules are engaged in cellular signalling and regulation of genes expression. On the other hand, ROS in excess lead to oxidation and damage of various cellular compounds. This article reviews the impact of NP on plants, with special emphasis on the oxidative response.

Effect of polystyrene nanoplastics on cell apoptosis, glucose metabolism, and antibacterial immunity of Eriocheir sinensis

The adverse effects of plastic waste and nanoplastics on the water environment have become a focus of global attention in recent years. In the present study, using adult Chinese mitten crabs (Eriocheir sinensis) as an animal model, the bioaccumulation and the in vivo and in vitro toxicity of polystyrene nanoplastics (PS NPs), alone or in combination with the bacteria, were investigated. This study aimed to investigate the effects of PS NPs on apoptosis and glucose metabolism in Chinese mitten crabs, and whether PS NPs could synergistically affect the antibacterial immunity of crabs. We observed that NPs were endocytosed by hemocytes, which are immune cells in crustaceans and are involved in innate immunity. The RNA sequencing data showed that after hemocytes endocytosed NPs, apoptosis and glucose metabolism-related gene expression was significantly induced, resulting in abnormal cell apoptosis and a glucose metabolism disorder. In addition, exposure to NPs resulted in changes in the antimicrobial immunity of crabs, including changes in antimicrobial peptide expression, survival, and bacterial clearance. In summary, NPs could be endocytosed by crab hemocytes, which adversely affected the cell apoptosis, glucose metabolism, and antibacterial immunity of Eriocheir sinensis. This study revealed the effects of NPs on crab immunity and lays the foundation for further exploration of the synergistic effect of NPs and bacteria.

Recent advances on the transport of microplastics/nanoplastics in abiotic and biotic compartments

Plastics enter the environment and break up into microplastics (MPs) and even nanoplastics (NPs) by biotic and abiotic weathering. These small particles are widely distributed in the environmental media and extremely mobile and reactive, easily suspending in the air, infiltrating into the soil, and interacting with biota. Current research on MPs/NPs is either in the abiotic or biotic compartments, with little attention paid to the fact that the biosphere as a whole. To better understand the complex and continuous movement of plastics from biological to planetary scales, this review firstly discusses the transport processes and drivers of microplastics in the macroscopic compartment. We then summarize insightfully the uptake pathways of MPs/NPs by different species in the ecological compartment and analyze the internalization mechanisms of NPs in the organism. Finally, we highlight the bioaccumulation potential, biomagnification effects and trophic transfer of MPs/NPs in the food chain. This work is expected to provide a meaningful theoretical body of knowledge for understanding the biogeochemical cycles of plastics.

The interaction of micro/nano plastics and the environment: Effects of ecological corona on the toxicity to aquatic organisms

Concerns about the micro/nano plastics (MNPs) exposure risks have risen in recent years. The ecological corona (EC), which is generated by the interaction between MNPs and environmental substances, has a significant impact on their environmental fate and ecological risks. As the largest sink of MNPs, the aquatic environment is of great significance for understanding the environmental behaviour of MNPs. Transmission Electron Microscope (TME), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscope (SEM), Dynamic Light Scattering (DLS) and other analytical methods have been used as effective methods to analyse the formation process of EC and detect the existing EC directly or indirectly on the surface of MNPs. The physicochemical properties of MNPs, complex aquatic environments and ageing time have been identified as the key factors affecting EC formation in aquatic environments. Moreover, the EC absorbed on MNPs significantly changed their environmental behaviour and toxicity to aquatic organisms. This review gives a full understanding of the EC formation progress on the surface of MNPs and different analytical methods for EC have been summarised which can further assist the ecological risk assessment of MNPs in the aquatic environment.

Eco-corona formation and associated ecotoxicological impacts of nanoplastics in the environment

Nanoplastics (NPs, diameter < 100 nm), are ubiquitously found in the environment including water, atmosphere, and soil because of their widespread applications and degradation resistant nature. Similarly, large quantities of natural organic matter (NOM) are present in the environment, in the form of extracellular polymeric substances (DNA, proteins, carbohydrates, etc.) and humic substances (humic acid, fulvic acid, humin, etc.), respectively released by organisms and degradation products of organic matter. These biomolecules interact with NPs and encapsulate to form a unique layered structure termed as eco-corona, which can alter the physicochemical characteristics, interaction, fate, and effects of plastic particles in the environment. The current study collated and reviewed recent findings emphasizing the progress of ecological (eco)-corona formation on NPs and affiliated toxicological effects in freshwater, marine water, and terrestrial ecosystems. The eco-corona layer formed around NPs may vary in sizes and biochemical composition, attributed mainly to the abundance, properties and physicochemical nature of both biomolecules and plastic particles, as well as medium properties and source of NOM in the ecosystem. Besides, most of the reviewed literature showed that eco-corona can reduces the toxicity of NPs with few exceptions, which demonstrates that eco-corona may enhance the NPs toxicity through the Trojan horse effect and longer retention time in biological system. Overall, this review also highlights future research perspectives for a better understanding of NPs toxicity modified by eco-corona, which is crucial to realizing the complex nature of interactions among plastic particles and NOM in a natural ecosystem.

Enrichment and dissemination of bacterial pathogens by microplastics in the aquatic environment

Microplastic pollution and associated impacts in the aquatic environment are spreading at an alarming rate worldwide. Plastic waste is increasing in the environment, and microplastics (MPs) are becoming a growing issue because they serve as vectors for pathogen transmission. This is the first comprehensive review that specifically addresses MPs as a source and vector of pathogenic bacteria, mainly associated with genera Vibrio, Pseudomonas, Acinetobacter, and so on, which are discovered to be more abundant on the aquatic plastisphere than that in the surrounding wastewater, freshwater, and marine water ecosystems. The horizontal gene transfer, chemotaxis, and co-selection and cross-selection could be the potential mechanism involved in the enrichment and dissemination of bacterial pathogens through the aquatic plastisphere. Further, bacterial pathogens through aquatic plastisphere can cause various ecological and human health impacts such as disrupted food chain, oxidative stress, tissue damages, disease transmission, microbial dysbiosis, metabolic disorders, among others. Last but not least, future research directions are also described to find answers to the challenging questions about bacterial pathogens in the aquatic plastisphere to ensure the integrity and safety of ecological and human health.

Single and combined toxicity of polystyrene nanoplastics and copper on Platymonas helgolandica var. tsingtaoensis: Perspectives from growth inhibition, chlorophyll content and oxidative stress

The combined toxic effects of nanoplastics and heavy metals on aquatic organisms have attracted widespread attention; however, the results are inconsistent and the mechanisms remain unclear. In this study, the single and combined toxicity effects of Cu and two types of polystyrene nanoplastics (PS-NPs; 50 nm PS and 55 nm PS-COOH) on Platymonas helgolandica var. tsingtaoensis were investigated, including growth inhibition, chlorophyll content, and oxidative stress. An adverse dose-response relationship on growth inhibition was found in the Cu treatment groups, which was related to the decrease in chlorophyll content and damage to cell membranes. The growth inhibitory effect of PS-NPs on microalgae increased with exposure time and concentration, and no significant difference was found in the two types of PS-NPs because of the negligible contribution of functional groups. A more significant increase in chlorophyll content was found in PS treatments than in PS-COOH treatments at 96 h because of the microscale aggregates formed by PS. Higher concentrations (≥ 50 mg/L) of PS-NPs caused membrane lipid peroxidation, which might be responsible for growth inhibition. In the combined exposure experiments, a synergistic effect on the growth inhibition rate was obtained using the independent action model and Abbott model. Combined exposure triggered more severe oxidative damage to the microalgae. Adsorption experiment results showed that there was no adsorption between PS-NPs and Cu, while the interaction of Cu and algal cells could be promoted due to the presence of the PS-NPs, which explained the increasing combined toxicity. This study could improve our understanding of the combined toxicity of nanoplastics and heavy metals and could provide a new explanation for the mechanism of combined toxicity.

Influence of protein configuration on aggregation kinetics of nanoplastics in aquatic environment

Aggregation kinetics of nanoplastics in aquatic environment are influenced by their interactions with proteins having different structures and properties. This study employed time-resolved dynamic light scattering (TR-DLS) to investigate the effects of 5 proteins (bovine hemoglobin (BHb), bovine (BSA) and human serum albumin (HSA), collagen type I (Col I), and bovine casein (CS)) on aggregation kinetics of polystyrene nanoplastics (PSNPs) under natural water conditions, which were simulated using various ionic strength (1-1000 mM NaCl and 0.01-100 mM CaCl₂), pH (3-9), and protein concentration (1-5 mg/L of total organic carbon). The results indicated that the interactions between proteins and PSNPs strongly depended on electrostatic properties, protein structures, and solution chemistries, which induced distinct aggregation behaviors in NaCl and CaCl₂ solutions. Electrostatic repulsion and steric hindrance dominated their interactions in NaCl solution by stabilizing PSNPs with the order of spherical BSA and disordered CS > heart-shaped HSA > fibrillar Col I; whereas positively charged BHb destabilized PSNPs with aggregation rate of 1.71 nm/s at 300 mM NaCl. In contrast, at CaCl₂ concentration below 20 mM, proteins destabilized PSNPs following the sequence of HSA > BHb > Col I > BSA depending on counterbalance among double layer compression, cation bridging, and steric hindrance; whereas CS stabilized PSNPs by precipitating Ca²⁺ that inhibited charge screening effect. Both protein concentration and solution pH affected protein corona formation, surface charge, and protein structure that altered stability of PSNPs. Characterizations using fluorescence spectroscopy, circular dichroism, and two-dimensional correlation analysis spectroscopy showed fluorescence quenching and ellipticity reduction of proteins, indicating strong adsorption affinity between PSNPs and proteins. The study provides insight to how protein configuration and water chemistry affect fate and transport of nanoplastics in aquatic environment.

Microplastic occurrence in urban and industrial soils of Ahvaz metropolis: A city with a sustained record of air pollution

This study investigates, for the first time, the concentration, distribution, fate and chemical composition of microplastics (MPs) in urban and industrial soils of Ahvaz metropolis, SW Iran. MP concentrations ranged from 100 to 3135 and 80 to1220 unit·kg^-1 in urban and industrial soils, respectively, with corresponding means of 619 and 390 unit·kg^-1. The most contaminated urban sites were located in the city center. Precisely these areas were affected by insufficient sanitation infrastructure including sewer systems, surface runoff collection and sewage treatment, and also high traffic loading in a commercial zone. MPs were found in various shapes, colours and sizes. In particular, microfibres (white-transparent and < 250 μm) were the most abundant MPs found in urban (70%) and industrial (55%) soils. Based on the weathering observed in the MPs, a large number of them originated from the fragmentation of other plastics and could have been photobleached. Polyethylene terephthalate and nylon were the dominant polymers in the MPs found in both industrial and urban soils and they could originate from textiles and tyres.

Effects of nanoplastic on cell apoptosis and ion regulation in the gills of Macrobrachium nipponense

Nanoplastic, ubiquitous in aquatic environments, are raising concern worldwide. However, studies on nanoplastic exposure and its effects on ion transport in aquatic organisms are limited. In this study, the juvenile oriental river shrimp, Macrobrachium nipponense, was exposed to five levels of nanoplastic concentrations (0, 5, 10, 20, 40 mg/L) in order to evaluate cell viability, ion content, ion transport, ATPase activity, and related gene expression. The results showed that the apoptosis rate was higher in the high concentration nanoplastic group (40 mg/L) compared to the low concentration nanoplastic group (5 mg/L) and the control group (0 mg/L). The ion content of sodium (Na⁺), potassium (K⁺), chloride (Cl^-), and calcium (Ca²⁺) showed a decreasing trend in gill tissue compared to the control group. The Na⁺K⁺-ATPase, V(H)-ATPase, Ca²⁺Mg²⁺-ATPase, and total ATPase activities in the gills of M. nipponense showed a general decrease with the increasement of nanoplastic concentration and time of exposure. When increasing nanoplastic concentration, the expression of ion transport-related genes in the gills of M. nipponense showed first rise then descend trend. As elucidated by the results, high nanoplastic concentrations have negative effect on cell viability, ion content, ion transport ATPase activity, and ion transport-related gene expression in the gills of M. nipponense. This research provides a theoretical foundation for the toxic effects of nanoplastic in aquaculture.

The presence of polystyrene nanoplastics enhances the MCLR uptake in zebrafish leading to the exacerbation of oxidative liver damage

The accumulation of diminutive plastic waste in the environment, including microplastics and nanoplastics, has threatened the health of multiple species. Nanoplastics can adsorb the pollutants from the immediate environment, and may be used as carriers for pollutants to enter organisms and bring serious ecological risk. To evaluate the toxic effects of microcystin-LR (MCLR) on the liver of adult zebrafish (Danio rerio) in the presence of 70 nm polystyrene nanoplastics (PSNPs), zebrafish were exposed to MCLR alone (0, 0.9, 4.5 and 22.5 μg/L) and a mixture of MCLR + PSNPs (100 μg/L) for three months. The results indicated that groups with combined exposure to MCLR and PSNPs further enhanced the accumulation of MCLR in the liver when compared to groups only exposed to MCLR. Cellular swelling, fat vacuolation, and cytoarchitectonic damage were observed in zebrafish livers after exposure to MCLR, and the presence of PSNPs exacerbated these adverse effects. The results of biochemical tests showed the combined effect of MCLR + PSNPs enhanced MCLR-induced hepatotoxicity, which could be attributed to the altered levels of reactive oxygen species, malondialdehyde and glutathione, and activities of catalase. The expression of genes related to antioxidant responses (p38a, p38b, ERK2, ERK3, Nrf2, HO-1, cat1, sod1, gax, JINK1, and gstr1) was further performed to study the mechanisms of MCLR combined with PSNPs aggravated oxidative stress of zebrafish. The results showed that PSNPs could improve the bioavailability of MCLR in the zebrafish liver by acting as a carrier and accelerate MCLR-induced oxidative stress by regulating the levels of corresponding enzymes and genes.

Effects of nanoplastic exposure on the growth performance and molecular characterization of growth-associated genes in juvenile Macrobrachium nipponense

Nanoplastic pollution has become a major issue in the aquatic environment while there are few studies examined the effects of nanoplastic exposure on crustaceans. To investigate this issue, we exposed juvenile shrimp, Macrobrachium nipponense to 75 nm polystyrene with 0, 5, 10, 20 and 40 mg/L nanoplastics concentrations for 28 days. The effects of nanoplastic exposure on the microstructure of the hepatopancreas, digestive enzyme activity and expression of growth-related genes were studied. The results showed that (1) adverse effects on the hepatopancreas were positively correlated with nanoplastic concentration; (David et al.) the activity of lipase, trypsin and pepsin was initially promoted and then inhibited with increasing nanoplastic concentration, whereas the activity of amylase was not significantly affected; (3) molting-associated genes were initially promoted and then inhibited with increasing nanoplastic concentration; (4) CDK2 gene was first cloned and molecular characteristics were analyzed. (5) polystyrene nanoplastics concentration >10 mg/L showed inhibition effect on CDK2 expression. These results indicated that nanoplastics affect the growth, digestive enzyme activity, hepatopancreas function and growth-related gene expression. Capsule: Our results identified the effects of nanoplastics on the growth performance of Macrobrachium nipponense in terms of digestion and molting.

To Waste or Not to Waste: Questioning Potential Health Risks of Micro- and Nanoplastics with a Focus on Their Ingestion and Potential Carcinogenicity

Micro- and nanoplastics (MNPs) are recognized as emerging contaminants, especially in food, with unknown health significance. MNPs passing through the gastrointestinal tract have been brought in context with disruption of the gut microbiome. Several molecular mechanisms have been described to facilitate tissue uptake of MNPs, which then are involved in local inflammatory and immune responses. Furthermore, MNPs can act as potential transporters ("vectors") of contaminants and as chemosensitizers for toxic substances ("Trojan Horse effect"). In this review, we summarize current multidisciplinary knowledge of ingested MNPs and their potential adverse health effects. We discuss new insights into analytical and molecular modeling tools to help us better understand the local deposition and uptake of MNPs that might drive carcinogenic signaling. We present bioethical insights to basically re-consider the "culture of consumerism." Finally, we map out prominent research questions in accordance with the Sustainable Development Goals of the United Nations.