Micro- and nanoplastic toxicity: A review on size, type, source, and test-organism implications

Unveiling the adsorption mechanism of perfluorooctane sulfonate onto polypropylene nanoplastics: A combined theoretical and experimental investigation

Polypropylene (PP) is a key component of nanoplastics detected globally in water, which can carry pollutants through co-transport. In this regard, the co-transport of perfluoroalkyl substances (PFAS) by nanoplastics (NPs) raises significant concern, as NPs can act as vectors that enhance PFAS uptake and bioaccumulation in organisms during co-exposure. In this context, research has shown interactions between NPs and PFAS, but the adsorption mechanism remains still unclear. In this work, a powerful synergic approach combining several computational and experimental techniques has been used to unveil the adsorption mechanism of perfluorooctanesulfonate (PFOS), which is one of the most widespread contaminants of emerging concerns (CECs) on PP nanoparticles. According to our DFT results, PFOS adsorbs onto the outer and inner surface of the nanoparticle, with a maximum adsorption energy of ≈ 18 kcal/mol and an adsorption mechanism mainly governed by dispersion forces between the two fragments. Batch experiments have confirmed that PFOS rapidly adsorbs on PP nanoparticle, showing that pH can reduce the adsorption capacity thus affecting the co-transport. Moreover, the dipole moment of the PFOS-nanoparticle complex has been found to be significantly larger as compared to the bare nanoparticle, resulting in a more pronounced transport in aqueous environment and making the PFOS-PP nanoparticle complex much more dangerous than the bare PP nanoparticle. Altogether, our results allowed us to disentangle the adsorption mechanism of PFAS on PP nanoparticles, which is a fundamental step to understand the co-occurrence of such dangerous pollutants in environmental matrices, as well as to obtain new information for toxicity and risk-models development.

Polystyrene microplastics (PS-MPs) harness copper presence and promote impairments in early zebrafish (Danio rerio) larvae: Developmental, biochemical, transcriptomic approaches and nontargeted metabolomics approaches

Due to their large specific surface area and strong hydrophobicity, microplastics (MPs) are highly susceptible to adsorb environmental pollutants, of which heavy metals (HMs) are the most representative inorganic pollutants. However, there is controversy in different studies as to whether the toxic effects of the combined action of MPs and HMs on zebrafish larvae are antagonistic or synergistic. Herein, we firstly evaluated the combined effects of 10 μm polystyrene MPs (PS-MPs) on zebrafish larvae after exposure for 96 h at two different concentrations (5 mg/L, 0.5 mg/L) and Cu2+ (0.05 mg/L). Our study primarily showed that the combined exposure of PS-MPs and Cu2+ could induce developmental toxicity, oxidative stress, immunotoxicity and neurotoxicity. Furthermore, LC/MS-based nontargeted metabolomics analysis demonstrated that the combined exposure of PS-MPs with Cu2+ induced metabolic disturbances. Furthermore, our results showed that the combined exposure of 10 μm PS-MPs with Cu2+ exhibited a synergistic effect on the toxicity of zebrafish larvae. In conclusion, this study provides a reference for future research related to combined exposure of PS-MPs and Cu2+ on fish.

Centrifugal microfluidic chip for multi-stage sorting and detection of microplastics at micron scale

BACKGROUND

As an emerging contaminant, microplastics(MPs) have been widely detected in the environment, the environmental risks it poses are also becoming more prominent. Among them, micron-sized MPs have relatively higher biotoxicity, necessitating a technique for processing and analysis to separate them by particle size and analyze their composition. The most commonly used MPs separation technology at present is the membrane filtration, which is easily to cause membrane blockage and set error accumulation. Centrifugal microfluidic technology received great attention as a high efficiency, low error and simple operation technology, has great potential for the separation of MPs.

RESULTS

In this paper, we have reported a multi-stage centrifugal microfluidic chip for the separation and detection of MPs (with diameter less than 63 μm). MPs of different diameters ranges were separated under the combination of Centrifugal force and Coriolis force, and orderly captured in four separation chambers according to their sizes. The capture rate of the microfluidic chip for polystyrene microspheres can reach about 87%. We also successfully separated MPs with irregular shapes. Under a rotation speed of 3500-4000 rpm, the maximum Pearson correlation coefficient between the volume equivalent diameters of the irregular MPs and the capture positions was about 0.84. Our proposed separation method was also applicable to MPs mixtures, which were successfully used for the separation of PVC, PC, and PS particles. The separated MPs can be directly identified to determine their chemical composition by Raman detection.

SIGNIFICANCE AND NOVELTY

The experimental results demonstrate that our strategy is promising for separating and detecting MPs of different particle sizes in the environment and effectively overcomes the problem of error accumulation in traditional membrane separation methods. Furthermore, the device and methods developed in this study provide a foundational framework for formulating robust environmental risk assessment system.

Differential effects of foodborne and waterborne micro(nano)plastics exposure on fish liver metabolism and gut microbiota community

Micro(nano)plastics (MNPs) primarily enter fish through two routes: directly ingestion via their diets and respiratory filtration through their gills. However, the specific impacts of these two routes on liver metabolism remain largely unknown. Here, we investigated the gene expression profiles of the liver of Nile tilapia Oreochromis niloticus following equivalent doses of foodborne and waterborne MNPs exposure. While the liver phenotypes of O. niloticus showed minimal differences between the two exposure routes, significant variations were observed in gene response patterns. Using WGCNA, we identified the key gene networks and KEGG pathways associated with each exposure type. The primary transcription factors regulating gene expression changes were thrb for foodborne exposure and fosl2 for waterborne exposure. The stimulus of foodborne MNPs primarily induced metabolic disorders through circadian rhythm, whereas waterborne MNPs induced inflammatory responses to affect host metabolism. By integrating gene expression alterations with gut microbiota enrichment data, we further found that Firmicutes, Fusobacteriota, Proteobacteria, and Chloroflexi jointly regulated the expression of mapk13 during foodborne exposure, whereas the expression of the most leading genes in waterborne exposure was predominantly influenced by Firmicutes. Collectively, our study demonstrated a distinct pattern in microbiota-gene gut-liver axis in O. niloticus in response to foodborne and waterborne MNPs exposure.

Polystyrene microplastics attenuated the impact of perfluorobutanoic acid on Chlorella sorokiniana: Hetero-aggregation, bioavailability, physiology, and transcriptomics

Microplastics (MPs) and perfluorobutanoic acid (PFBA), emerging contaminants, are ubiquitous in the environment and toxic to organisms. The interaction of MPs with other contaminants can affect their toxicity. However, the impact of MPs on PFBA toxicity remains unknown. This research investigated the individual and combined impacts of polystyrene microplastics (PS) and PFBA to Chlorella sorokiniana based on cellular responses and transcriptome analyses. Results showed that both PS and PFBA induced excessive ROS generation, causing cell membrane damage and photosynthesis inhibition, ultimately inhibiting Chlorella sorokiniana growth. The highest inhibition was observed for small particle size PS, with a maximum inhibition rate of 15.98 ± 1.24 % (3PS group). Notably, the combined toxicity of PFBA and PS exhibited antagonism, which was attributed to PFBA adsorption and PS hetero-aggregation via massive EPS secretion, resulting in decreased PS and PFBA bioavailability. Transcriptomic analysis elucidated that EPS secretion was promoted owing to the up-regulation of carbohydrate, amino acid, and energy metabolism (carbon fixation, oxidative phosphorylation, and TCA cycle). Enhanced EPS secretion, ABC transport, and antioxidant response alleviated PS and PFBA toxicity. Our findings offer valuable data for the joint ecotoxicity of PFASs and MPs, contributing to environmental risk assessment of co-pollution.

Increased assimilation efficiency and mortality rate in Gammarus fossarum exposed to PVC microplastics

Shredder organisms play a key role in rivers by feeding and fragmenting coarse organic matter that will then be exploited by other consumers. The effects of microplastics (MPs) on Gammarus sp., an ubiquitous genus of freshwater amphipods, and its shredding activity have been broadly investigated. However, the potential behavioral and physiological effects of different sizes of MPs on Gammarus sp. remain overlooked despite the recognized influence of MP size on MP toxicity. This study investigated the effects of a 28-day exposure to four different concentrations of two size fractions of PVC-microplastics (PVC-MPs), on Gammarus fossarum mortality rate, feeding rate, assimilation efficiency, and expression of proteins involved in key processes. Increased mortality was observed for all treatments exposed to PVC-MPs, with higher mortality in the presence of smaller PVC-MPs at the highest concentration. No protein biomarker modulation was observed in presence of PVC-MPs, suggesting that no metabolic stress but direct physical damages of PVC-MPs might have led to the observed mortalities. No difference was observed for feeding rates, but a higher assimilation efficiency was measured for individuals exposed to PVC-MPs, regardless of the concentration. This could be due to energy reallocation towards defense mechanisms or indicate a potential shift in digestive microbiota. This study highlighted the toxicity of PVC-MPs, particularly of smaller sizes and even at relatively low concentration, for Gammarus fossarum. PVC-MP pollution may therefore alter the functional integrity of river ecosystems by reducing the abundance of shredder organisms and, subsequently, the process of leaf litter decomposition.

Protective effect of curcumin against microplastic and nanoplastics toxicity

Microplastics and nanoplastics (MNPs) are present in urban dust and the aquatic environments of industrialized cities. MNPs in the human body accumulate in the lymphoid follicles, Peyer's patches of the gastrointestinal tract, and pulmonary vascular endothelial cells, which slowly result in toxicity. Since previous studies introduced curcumin as a natural protective agent against environmental toxins, we reviewed preclinical studies that had used curcumin to protect organs or cells from toxicity secondary to exposure to MNPs. It was found that exposure to MNPs resulted in osteolysis, immunotoxicity, thyroid disturbances, nephrotoxicity, neurotoxicity, hepatotoxicity, pulmonary toxicity, gastrointestinal toxicity, cardiovascular toxicity, and especially endocrine, and reproductive toxicity. Nevertheless, except for one study reviewed, curcumin restored all oxidative and histopathological damages induced by MNPs to normal due to curcumin's inherent antioxidant, antiapoptotic, anti-inflammatory, and anti-proliferative properties.

Polystyrene nanoplastics chronic exposure cause zebrafish visual neurobehavior toxicity through TGFβ-crystallin axis

The ubiquitous presence of micro-and nanoplastics (MNPs) in the environment and everyday products has attracted global attention for their hazardous risks. However, the effects and underling mechanisms of MNPs chronic exposure on behavioral/visual changes of the adult and offspring remain unclear. The present study investigated the impact of polystyrene (PS) nanoplastics of 80, 200 and 500 nm diameters on zebrafish visual behaviors at an environmentally relevant concentration of 0.1 mg/L. Exposure to PS resulted in zebrafish hyperactivity, enhanced aggression, compacted shoaling and less sociability, and especially suppressed the adult optokinetic response (OKR) and offspring larval phototactic behavior, with the 500 nm PS being the most detrimental. Histopathological analysis showed 500 nm PS caused significant structural damage to the retina's pigment epithelium (RPE), photoreceptor cells (PRC), and crystalline lens. Fluorescence observation found PS accumulation in retinal layers correlated with reduced oligodendrocyte transcription factor 2 (Olig2) in optic nerve. Further transcriptomic analysis of the adult eye tissue revealed that 500 nm PS affected the transforming growth factor β (TGFβ) and phototransduction signaling pathways, dysregulated visual perception and lens development, potentially leading to dysopia in zebrafish. Specifically, TGFβ and its regulated-extracellular matrix/inflammatory factors and crystallin genes were increased, but the visual perception genes were decreased, suggesting the TGFβ-crystallin axis disorders contribute to the eye dysfunction induced by PS exposure. Collectively, our results provide new evidence revealing the molecular mechanisms of PS-induced visual toxicity and neurobehavioral changes highlighting that MNPs may pose a risk to vision health.

Global distribution characteristics and ecological risk assessment of microplastics in aquatic organisms based on meta-analysis

As microplastic pollution in the natural environment intensifies, the risk of microplastic contamination faced by aquatic organisms has garnered increasing widespread attention. Most studies have primarily focused on the impacts of microplastics within specific regions and on particular species. However, with the global migration of microplastics, it is necessary to conduct comprehensive research on the distribution characteristics, ingestion mechanisms, and ecological impacts of microplastics across various aquatic organisms. To address this research gap, the present study systematically evaluates the distribution status of microplastics in global aquatic organisms and assesses their potential ecological risks. Firstly, a review of the sources and impacts of microplastics within aquatic organisms is provided. Secondly, a bibliometric analysis is employed to examine the current research landscape and trends, coupled with a quantitative analysis of how the biological characteristics of aquatic organisms influence microplastic ingestion and the distribution patterns of microplastics within these organisms. Thirdly, the study investigates the mechanisms by which microplastics affect aquatic food chains by examining their impact on organisms at different trophic levels. Finally, strategies to reduce microplastic input into water bodies and future research directions are proposed. The findings offer scientific foundations and decision-making support for global microplastic pollution control, aiming to protect the health and sustainable development of aquatic ecosystems.

Adolescent exposure to micro/nanoplastics induces cognitive impairments in mice with neuronal morphological damage and multi-omic alterations

Polystyrene micro/nanoplastics (MPs/NPs) are globally recognized environmental concerns due to their widespread pollution and detrimental effects on physiological functions. However, the neurotoxic effects and underlying mechanisms of MPs/NPs on brain function in adolescents remain incompletely understood. This study investigated the effects of polystyrene MPs/NPs on neurobehavioral function in adolescent mice, utilizing multi-omic analysis and molecular biology assays to explore potential mechanisms. Following oral exposure of MPs (5 μm) or NPs (0.5 μm) at 0.5 mg/day for 4 weeks, NPs induced more severe cognitive impairment in mice than MPs, as assessed by the Morris water maze and Y-maze tests. This impairment might be associated with the neuron loss and neurogenesis inhibition caused by NPs, while dendritic spine loss mediated by MPs in the hippocampus. Furthermore, analysis of hippocampal transcriptome and Western blotting indicated the potential involvement of the PI3K/AKT pathway in NPs-induced neurotoxicity. Meanwhile, exposure to NPs induced more pronounced disruptions in the hippocampal metabolome and gut microbiota, and strong correlations were observed between changes in hippocampal metabolites and gut bacteria. This study elucidated the toxicity mechanism of MPs and NPs in inducing cognitive impairment in adolescent mice, providing insights into their toxicological impacts and potential strategies for intervention.

Cellular and biochemical alterations induced by diesel oil in the brown alga Sargassum cymosum var. stenophyllum cultured in vitro

The effect of the in vitro acute exposure to diesel oil (0.001%, 0.01%, 0.1%, and 1%, v/v) has been evaluated in the brown seaweed Sargassum cymosum var. stenoplhyllum by determining the contents of photosynthetic pigments, phenolic compounds, and morphological and cellular changes. In vitro cultures of S. cymosum were exposed to diesel oil for 30min, 1h, 12h, and 24h under laboratory-controlled conditions. Chlorophyll a and c contents increased after diesel oil exposure as the amounts of carotenoids did not show a clear trend along the experimental period. However, a reduction in the concentration of phenolic compounds was detected by chemical analysis, a finding further corroborated by electron microscopy and cytochemical analyzes. The thickness of the cell wall showed to be augmented and the accumulation of phenolic compounds therein was also detected after exposure to that petroleum derivative. Besides, morphological analysis through scanning electron microscopy revealed irregularities in the cell surface, as transmission electronic microscopy indicated an increased number of vacuoles in the cells. Based on these results, it could be concluded that the acute exposure to diesel oil brings about a stress effect in S. cymosum var. stenophyllum, promoting alterations in the seaweed secondary metabolism, stimulating protective mechanisms against oxidative stress, and changing cell's morphological and ultrastructural traits.

Strategies for the Remediation of Micro- and Nanoplastics from Contaminated Food and Water: Advancements and Challenges

Micro- and nanoplastic (MNP) pollution is a significant concern for ecosystems worldwide. The continuous generation and extensive utilization of synthetic plastics have led to the widespread contamination of water and food resources with MNPs. These pollutants originate from daily-use products and industrial waste. Remediation of such pollutants is essential to protect ecosystems and human health since these ubiquitous contaminants pose serious biological and environmental hazards by contaminating food chains, water sources, and the air. Various remediation techniques, including physical, chemical, sophisticated filtration, microbial bioremediation, and adsorption employing novel materials, provide encouraging avenues for tackling this worldwide issue. The biotechnological approaches stand out as effective, eco-friendly, and sustainable solutions for managing these toxic pollutants. However, the complexity of MNP pollution presents significant challenges in its management and regulation. Addressing these challenges requires cross-disciplinary research efforts to develop and implement more efficient, sustainable, eco-friendly, and scalable techniques for mitigating widespread MNP pollution. This review explores the various sources of micro- and nanoplastic contamination in water and food resources, their toxic impacts, remediation strategies-including advanced biotechnological approaches-and the challenges in treating these pollutants to alleviate their effects on ecosystems and human health.

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

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

Genes of filter-feeding species as a potential toolkit for monitoring microplastic impacts

Microplastics (MPs) are ubiquitous in the marine environment and impact organisms at multiple levels. Understanding their actual effects on wild populations is urgently needed. This study develops a toolkit to monitor changes in gene expression induced by MPs in natural environments, focusing on filter-feeding and bioindicator species from diverse ecological and taxonomic groups. Six candidate genes -Caspase, HSP70, HSP90, PK, SOD, and VTG- and nine filter-feeding species -two branchiopods, one copepod, five bivalves and one fish- were selected based on differential expression in response to MPs exposure (mainly the widely used polystyrene and polyethylene polymers) reported in over 30 publications. Some genes are particularly determinant, such as HSP70 and HSP90 (key to managing a wide range of stressors) and SOD (critical for addressing oxidative stress), as they are more directly related to stress. PK is related to carbohydrate metabolism (alterations in energy metabolism); VTG is associated with reproductive problems; Caspase mediates in apoptosis. Each gene in the toolkit plays a role depending on the type of stress assessed, and their combination provides a comprehensive understanding of the impacts of MPs. Differences in gene expressions between species and the exposure thresholds were found. These genes were examined in various scenarios with different types, concentrations, and sizes of MPs, alone or with other stressors. The toolkit offers significant advantages, allowing a comprehensive study of the impact of MPs and focusing on filtering bioindicator species, thus enabling pollution assessment and long-term monitoring. It will outperform traditional methods like tissue counts of MPs where only physical damage is visible, providing a deeper understanding. To our knowledge, this is the first toolkit of its kind.

Exploring micro(nano)plastics toxicity from an environmental management perspective: Zebrafish as a vital bridge for assessing potential human health risks

The pollution stemming from the unwarranted utilization and inadequate disposal of plastic products is undergoing rapid escalation. The problem of micro(nano)plastics (MNPs) pollution has recently garnered significant attention, and the issue of human exposure to MNPs cannot be disregarded. However, the present state of research concerning human exposure to MNPs remains in its early stages. The inherent uncertainty and variability associated with MNPs pose significant obstacles to conducting related studies. In order to enhance comprehension of the potential health risks associated with human exposure to MNPs, the utilization of zebrafish as an assessment tool was deemed appropriate. Zebrafish, as one of the most effective toxicological models, assume a significant role in both environmental monitoring and health modeling. This study provides a review of the effects of exposure to MNPs on zebrafish. The findings demonstrate that such exposure can elicit behavioral and physiological alterations in zebrafish, subsequently resulting in a range of toxic consequences. Simultaneously, this study conducts a comparative analysis of the effects of human and zebrafish exposure to MNPs in physiology, exposure environment, and toxicokinetic/toxicodynamic, leveraging the shared characteristics between zebrafish and humans to augment comprehension regarding human exposure to MNPs. Zebrafish model plays a key role in exploring gene expression in human homologous pathways caused by MNPs exposure, and strengthens the understanding of the risk of MNPs exposure. However, physiological, metabolic, and exposure circumstances limit its extrapolation to humans. Furthermore, the reference value and challenge associated with employing zebrafish as a model to discern human health hazards linked to MNPs are assessed, accompanied by suggestions for future research endeavors.

Metabolomics reveals the toxicity of polystyrene nanoplastics in the gills of Acrossocheilus yunnanensis

Although the ecotoxicity of polystyrene nanoplastics (PS-NP) to fish has been widely reported, their impact on the metabolic processes in fish gills and the underlying mechanisms remains unclear. Here, we investigated the effects of PS-NP on the morphology, oxidative stress, and metabolism of Acrossocheilus yunnanensis gills using conventional physicochemical indicators and metabolomics analysis. The results showed that PS-NP caused oxidative stress, and resulted in gill tissue lesions (e.g., proliferation and sloughing of gill epithelial cells). Metabolomics results showed that PS-NP exposure induced 75-164 differentially expressed metabolites (DEMs) in fish gills, and they were mainly related to lipid metabolism. DEMs induced by high concentration of PS-NP compared with low concentration of PS-NP were not only significantly enriched in glycerophospholipid metabolism, but also in sphingolipid metabolism, nucleic acid metabolism, and a variety of signaling pathways. In conclusion, the results of this work suggest that PS-NP cause disruption of phospholipid metabolism mainly by disrupting the integrity of gill tissue, which provides a new perspective for understanding the impact mechanism of PS-NP on fish gills. Given that fish play essential roles in maintaining ecological balance, the adverse effects of PS-NP on fish gills could ultimately disrupt the stability and health of the aquatic ecosystem.

Size-Resolved SERS Detection of Trace Polystyrene Nanoplastics via Selective Electrosorption

Microplastics and nanoplastics are emerging contaminants that pose a threat to the environment and human. Spectroscopic technologies are advantageous in analyzing nanoplastics, but it is challenging to selectively detect nanoplastics with different size thresholds. In this work, the hyphenated method of electrosorption and surface-enhanced Raman spectroscopy (ES-SERS) was developed for the simple, rapid, and size-resolved analysis of trace polystyrene (PS) nanoplastics from 20 to 300 nm. A rough silver was used as both the working electrode for electrosorption and the substrate for the SERS response. By applying a positive electric potential to the rough silver, the PS nanoplastics accelerated toward the silver surface and were adsorbed tightly at the SERS "hot spot" inside the rough silver nanostructure. The proposed ES-SERS method achieved a detection limit of 100 ng/L for 300 and 100 nm PS, 50 ng/L for 50 nm PS, and 30 ng/L for 20 nm PS nanoplastics. It is worth noting that smaller nanoplastics typically exhibit larger analytical enhancement factor values in ES-SERS. According to the difference in electromigration behavior of PS in various sizes, PS nanoplastics under a certain size can be selectively enriched and detected by controlling the electrosorption time. The ES-SERS method was successfully demonstrated for detecting nanoplastics released from the lids of disposable beverage cups. This work opens up new possibilities for size-resolved analysis of nanoplastics.

Activated hedgehog and insulin ligands by decreased transcriptional factor DAF-16 mediate transgenerational nanoplastic toxicity in Caenorhabditis elegans

In Caenorhabditis elegans, transcriptional factor DAF-16 in insulin signaling pathway played important role in regulating transgenerational nanoplastic toxicity. Activation of insulin signals mediated transgenerational toxicity of polystyrene nanoparticle (PS-NP) by inhibiting DAF-16. Among identified germline ligands, expression of wrt-3 encoding hedgehog ligand was increased by RNAi of daf-16 in PS-NP exposed C. elegans. In PS-NP exposed C. elegans, expressions of 4 other germline hedgehog ligand genes and 10 hedgehog receptor genes were increased by daf-16 RNAi. Among these candidate genes, expressions of hedgehog ligand genes (grl-15, grl-16, qua-1, and wrt-1) and hedgehog receptor genes (ptr-23, scp-1, ptd-2, and ncr-1) could be increased by PS-NP (1-100 μg/L), and their transgenerational expressions were observed after PS-NP exposure. RNAi of grl-15, grl-16, qua-1, wrt-1, ptr-23, scp-1, ptd-2, and ncr-1 caused resistance to transgenerational PS-NP toxicity. In nematodes exposed to PS-NPs, RNAi of wrt-3, grl-15, grl-16, qua-1, and wrt-1 at parental generation (P0-G) inhibited expressions of ptr-23, scp-1, ptd-2, and ncr-1 in their offspring. Moreover, we observed increased expressions of insulin peptides genes (ins-3, ins-39, and daf-28) in PS-NP exposed daf-16(RNAi) nematodes, suggesting formation of feedback loop. We raise the molecular basis for formation of toxicity on multiple generations after nanoplastic exposure at P0-G.

Nanoplastic release from disposable plastics: Correlation with maximum service temperature

The potential for bioaccumulation of nanoplastics (NPs, <1 µm) increases as the particle size decreases. Since several disposable plastic products used daily may release NPs, their intake may be unavoidable. Therefore, it is crucial to examine the release patterns of NPs from these products. This study investigates the relationship between NP release and the Maximum Service Temperature (MST) of five plastic types, confirming the correlation under real-world conditions. The releasing tendencies of NPs were investigated using plastic pellets. We simulated the packaging of hot food in plastic containers, considering the physical dynamics of food delivery, and replicated cooking in an oven and microwave. We observed that the mass of NPs released tended to reach its maximum at the material's MST. In real-life conditions, the release of NP was found to increase with higher container content temperatures and longer packaging or cooking durations. Physical impacts were confirmed to be the most significant contributors to NP release. Moreover, Higher microwave power levels lead to greater NP release, with polar materials releasing more NPs compared to non-polar materials. Consequently, to minimize NP ingestion, it is recommended to use containers made from non-polar materials with a high MST.

Trophic transfer and bioaccumulation of nanoplastics in Coryphaena hippurus (mahi-mahi) and effect of depuration

Ocean plastic pollution is a global concern, exacerbated by the distinctive physiochemical characteristics of nanoplastics (NPs), making it crucial to study the impacts on marine animals, particularly fish, given their ecological and economic importance. Both trophic transfer and waterborne exposure are potential modes of NP entry into seafood for human consumption Although the majority of studies have focused on in-vitro impacts of NP exposure in fish, in-vivo methods can offer a more holistic understanding of these impacts. This study investigates polystyrene NP transfer to Coryphaena hippurus (mahi-mahi) larvae, a widely consumed fish and significant marine predator, during the early life stage. Brachionus plicatilis (rotifers) were exposed to NPs, and subsequently fed to C. hippurus larvae, with exposure duration ranging from 24 to 96 h. Significant NP transfer was observed via the food chain, varying with exposure duration. A depuration study over 72 h, simulating intermittent NP exposure, revealed substantial NP excretion but also notable retention in the larvae. Biodistribution analysis indicated that most NPs accumulated in the gut, with a significant portion remaining post-depuration and some translocating to other body areas containing vital organs like the heart, liver, and gall bladder. Despite no significant effects on body length and eye diameter during this short study period, histopathological analysis revealed intestinal tissue damage in the larvae. Overall, this study provides valuable insight into the trophic transfer of NPs in marine food webs, emphasizing the need for further research on ecological impacts and highlighting the importance of addressing NP contamination to protect marine ecosystems and food safety.

Transgenerational response of germline histone acetyltransferases and deacetylases to nanoplastics at predicted environmental doses in Caenorhabditis elegans

Nanoplastics could cause toxic effects on organism and their offsprings; however, how this transgenerational toxicity is formed remains largely unclear. We here examined potential involvement of germline histone acetylation regulation in modulating transgenerational toxicity of polyetyrene nanoparticle (PS-NP) in Caenorhabditis elegans. At parental generation (P0-G), PS-NP (1-100 μg/L) decreased expressions of germline cbp-1 and taf-1 encoding histone acetyltransferases, as well as germline expressions of sir-2.1 and hda-3 encoding histone deacetylase. Decrease in these 4 germline genes were also observed in the offspring of PS-NP (1-100 μg/L) exposed nematodes. Germline RNAi of cbp-1, taf-1, sir-2.1 and hda-3 resulted in more severe transgenerational PS-NP toxicity on locomotion and brood size. Meanwhile, in PS-NP exposed nematodes, germline RNAi of cbp-1, taf-1, sir-2.1 and hda-3 increased expression of genes encoding insulin, FGF, Wnt, and/or Notch ligands and expressions of their receptor genes in the offspring. Susceptibility to transgenerational PS-NP toxicity in cbp-1(RNAi), taf-1(RNAi), sir-2.1(RNAi), and hda-3 (RNAi) was inhibited by RNAi of these germline ligands genes. Moreover, histone deacetylase inhibition served as molecular initiating event (MIE) leading to transgenerational toxicity in epigenetic adverse outcome pathway (AOP) for nanoplastics. Our data provided evidence that germline histone acetylation regulation functioned as an important mechanism for transgenerational toxicity of nanoplastics at predicted environmental doses (PEDs) by affecting secreted ligands in organisms.

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

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

New Horizons in Micro/Nanoplastic-Induced Oxidative Stress: Overlooked Free Radical Contributions and Microbial Metabolic Dysregulations in Anaerobic Digestion

Excessive production of reactive oxygen species (ROS) induced by micro/nanoplastics (MPs/NPs) is highly toxic to microbes. However, the mechanisms underlying ROS generation and metabolic regulation within anaerobic guilds remain poorly understood. In this study, we investigated the effects of environmentally relevant levels of polypropylene (PP)-MPs/NPs on oxidative stress and microbial ecology during anaerobic digestion (AD). Electron paramagnetic resonance spectroscopy revealed that PP-MPs/NPs elevated the concentrations of environmentally persistent free radicals (EPFRs) and derived hydroxyl radicals (•OH). EPFRs were identified as the primary contributors to •OH generation, as evidenced by a high Spearman correlation coefficient (r = 0.884, p < 0.001) and free radical-quenching studies. The formation of •OH enhanced ROS production by 86.2-100.9%, resulting in decreased cellular viability and methane production (by 37.5-50.5%) at 100 mg/g TS PP-MPs/NPs. Genome-centric metagenomic and metatranscriptomic analyses suggested that PP-MPs/NPs induced the reassembly of community structures, re-evolution of functional traits, and remodeling of interspecies interactions. Specifically, PP-MPs/NPs induced a shift in methanogen consortia from hydrogenotrophic Methanofollis sp. to acetoclastic and hydrogenotrophic Methanothrix soehngenii, primarily because of the latter's diverse ingestion patterns, electron bifurcation complexes, and ROS-scavenging abilities. Downregulation of genes associated with antioxidative defense systems (i.e., sodN, katA, and osmC) and ROS-driven redox signal transduction pathways (c-di-AMP and phosphorylation signaling pathways) provided insights into the mechanisms underlying ROS-induced microbial metabolic dysregulation. Our findings enhance the understanding of microbial ecological and metabolic traits under MPs/NPs stressors, facilitating the control of MPs/NPs toxicity and the stabilization of AD processes.

Toxic effects of microplastic and nanoplastic on the reproduction of teleost fish in aquatic environments

Microplastics and nanoplastics are widely present in aquatic environments and attract significant scholarly attention due to their toxicity, persistence, and ability to cross biological barriers, which pose substantial risks to various fish species. Microplastics and nanoplastics can enter fish through their digestive tract, gills and skin, causing oxidative damage to the body and adversely affecting their reproductive system. Given that fish constitute a crucial source of high-quality protein for humans, it is necessary to study the impact of microplastics on fish reproduction in order to assess the impact of pollutants on ecology, biodiversity conservation, environmental sustainability, and endocrine disruption. This review explores the reproductive consequences of microplastics and nanoplastics in fish, examining aspects such as fecundity, abnormal offspring, circadian rhythm, gonad index, spermatocyte development, oocyte development, sperm quality, ovarian development, and changes at the molecular and cellular level. These investigations hold significant importance in environmental toxicology.

Dose-dependent effects of polystyrene nanoplastics on growth, photosynthesis, and astaxanthin synthesis in Haematococcus pluvialis

Microalgae play an important role in aquatic ecosystems, but the widespread presence of micro- and nano-plastics (MNPs) poses significant threats to them. Haematococcus pluvialis is well-known for its ability to produce the antioxidant astaxanthin when it experiences stress from environmental conditions. Here we examined the effects of polystyrene nanoplastics (PS-NPs) at concentrations of 0.1, 1, and 10 mg/L on H. pluvialis over an 18-day period. Our results show that PS-NPs caused a significant, dose-dependent inhibition of H. pluvialis growth and a reduction in photosynthesis. Furthermore, PS-NPs severely damaged the morphology of H. pluvialis, leading to cell shrinkage, collapse, content release, and aggregation. Additionally, PS-NPs induced a dose-dependent increase in soluble protein content and a decrease in the production of extracellular polymeric substances. These findings indicate that PS-NPs has the potential to adversely affect both the physiology and morphology of H. pluvialis. An increase in reactive oxygen species and antioxidant enzyme activities was also observed, suggesting an oxidative stress response to PS-NPs exposure. Notably, the synthesis of astaxanthin, which is crucial for H. pluvialis's survival under stress, was significantly inhibited in a dose-dependent manner under strong light conditions, along with the down-regulation of genes involved in the astaxanthin biosynthesis pathway. This suggests that PS-NPs exposure reduces H. pluvialis's ability to survive under adverse conditions. This study enhances our understanding of the toxic effects of PS-NPs on microalgae and underscores the urgent need for measures to mitigate MNP pollution to protect aquatic ecosystems.

In vivo visualization of environmentally relevant microplastics and evaluation of gut barrier damages in Artemia franciscana

Although irregularly-shaped label-free microplastics (MPs) are predominantly distributed in the environment, non-destructive analysis of environmentally relevant MPs in organisms is still challenging. The purpose of the study is to suggest in vivo visual evidence of the uptake and effect of environmentally relevant MPs in organism. Transparent irregularly-shaped high-density polyethylene was selected as an environmentally relevant model MP and exposed to brine shrimp (Artemia franciscana). As a result, we suggest the application of SEM/EDX and coherent anti-Stokes Raman scattering (CARS) microspectroscopy as complementary tools to secure in vivo visual evidence of irregularly-shaped unlabeled MPs in living organisms without chemical digestion for biodistribution observations. Biological transmission electron microscopy also provides how ingested MPs physically affects the digestive tract in the brine shrimp which is rarely reported. In terms of environmental implications, this study would advance ecotoxicological research on microplastic pollution by providing a cutting-edge tool for investigating the bioavailability and ecotoxicity of environmentally relevant MPs in ecosystems.

Screening of optimal cleaning methods to reduce microplastic residues on strawberry surfaces: Characterization of microplastics in strawberry wash water

Microplastics are widespread in facility strawberry greenhouses and can be deposited on the surface of strawberries through air currents. Investigating effective cleaning methods represents a viable strategy to reduce human ingestion of MPs. Therefore, different cleaning methods were compared: ultrasonic cleaning for 30 min, deionized water rinsing once, deionized water immersion for 30 min, and fruit immersion in washing salt for 30 min. The MPs in strawberry washing water were analyzed and compared using laser direct infrared imaging to investigate their characteristics and the optimal reduction of MPs on the surface of strawberries. The quality of the cleaning results was in the following order: water immersion > washing salt immersion > water rinsing > ultrasound. Water immersion was 1.3-2 times more effective in removing microplastics than other treatments. Furthermore, 21 polymer types were detected in the samples. Most MPs were less than 50 µm in size. The main polymers in this size range were polyamide, chlorinated polyethylene, and polyethylene terephthalate, and they mainly existed as fragments, fibers, and beads. This study provides a valuable reference for reducing human intake of microplastics through fresh fruits and vegetables.

Plastic pollution in terrestrial ecosystems: Current knowledge on impacts of micro and nano fragments on invertebrates

The increasing accumulation of small plastic particles, in particular microplastics (>1 µm to 5 mm) and nanoplastics (< 1 µm), in the environment is a hot topic in our rapidly changing world. Recently, studies were initiated to better understand the behavior of micro- and nanoplastics (MNP) within complex matrices like soil, as well as their characterization, incorporation and potential toxicity to terrestrial biota. However, there remains significant knowledge gaps in our understanding of the wide-extent impacts of MNP on terrestrial invertebrates. We first summarized facts on global plastic pollution and the generation of MNP. Then, we focused on compiling the existing literature examining the consequences of MNP exposure in terrestrial invertebrates. The diversity of investigated biological endpoints (from molecular to individual levels) were compiled to get a better comprehension of the effects of MNP according to different factors such as the shape, the polymer type, the organism, the concentration and the exposure duration. The sublethal effects of MNP are acknowledged in the literature, yet no general conclusion was drawn as their impacts are highly dependent on their characteristic and experimental design. Finally, the synthesis highlighted some research gaps and remediation strategies, as well as a protocol to standardize ecotoxicological studies.

Beyond microbeads: Examining the role of cosmetics in microplastic pollution and spotlighting unanswered questions

The presence of microplastics in cosmetics and personal care products (C&PCPs) has been increasingly in the public eye since the early 2010s. Despite increasing research into the potential environmental and health effects of microplastics, most research to date on microplastics in C&PCPs has investigated "rinse-off" products, while the potential impacts of "leave-on" C&PCPs have been largely neglected, despite these products being purchased in greater volumes and often having two or more microplastic ingredients in their formulations(CosmeticsEurope, 2018b). This review aims to synthesize the current knowledge of microplastic in C&PCPs, assessing the potential environmental and human health impacts of C&PCPs and discussing the regulatory implications. The lack of studies on leave-on C&PCPs is significant, suggesting a severe knowledge gap regarding microplastic presence in, and emissions from, C&PCPs. There is a noticeable lack of studies on the (eco)toxicological consequences of microplastic exposure from C&PCPs. As a result, significant aspects of microplastic contamination may be overlooked in the microplastic legislations emerging globally (including from the European Commission), which intend to restrict microplastic use in C&PCPs but focus on rinse-off C&PCPs only. This review highlights the potential consequences of microplastics in leave-on C&PCPs for regulatory decision-making, particularly as alternatives to microplastics are considered during the phase-out periods and spotlights the need for sufficient monitoring and research on these alternatives, to avoid unforeseen consequences.

Combined toxicity of pristine or artificially aged tire wear particles and bisphenols to Tigriopus japonicus

Tire wear particles (TWPs) are considered an important component of microplastic pollution in the marine environment and occur together with a variety of aquatic pollutants, including frequently detected bisphenols. The adverse effects of TWPs or bisphenols on aquatic organisms have been widely reported. However, the combined toxicity of TWPs and bisphenols is still unknown. In this study, the combined toxicity of both pristine (p-) and aged TWPs (a-TWPs) and four bisphenols ((bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS), and bisphenol AF (BPAF)) to Tigriopus japonicus was evaluated. TWPs increased the toxicity of BPA and BPF but decreased the toxicity of BPAF. For BPS, there was synergistic toxic effect in the presence of p-TWPs, but slightly antagonistic effect was observed in the presence of a-TWPs. This adsorption of BPAF by TWPs resulted in a reduction of its toxicity to the copepod. A-TWPs could release more Zn than p-TWPs, and the released Zn contributed to the synergistic effect of TWPs and BPA or BPF. The aggregation formed by TWPs in certain sizes (e.g., 90-110 μm) could cause intestinal damage and lipid peroxidation in T. japonicus. The synergistic effect of p-TWPs and BPS might be due to the aggregation size of the binary mixture. The results of the current study will be important to understand the combined toxic effect of TWPs and bisphenols and the potential toxic mechanisms of the binary mixture.

Nanoplastic at environmentally relevant concentrations induces toxicity across multiple generations associated with inhibition in germline G protein-coupled receptor CED-1 in Caenorhabditis elegans

Nanoplastics at environmentally relevant concentrations (ERCs) could cause transgenerational toxicity on organisms. Caenorhabditis elegans is an important model for the study of transgenerational toxicology of pollutants. Nevertheless, the underlying mechanisms for the control of transgenerational nanoplastic toxicity by germline signals remain largely unclear. In C. elegans, exposure to 1-100 μg/L polystyrene nanoparticle (PS-NP) decreased expression of germline ced-1 encoding a G protein-coupled receptor at parental generation (P0-G). After PS-NP exposure at P0-G, transgenerational decrease in germline ced-1 expression could be detected. Meanwhile, the susceptibility to transgenerational PS-NP toxicity was observed in ced-1(RNAi) animals. After PS-NP exposure at P0-G, germline RNAi of ced-1 increased expressions of met-2 and set-6 encoding histone methylation transferases. The susceptibility of ced-1(RNAi) to transgenerational PS-NP toxicity could be inhibited by RNAi of met-2 and set-6. Moreover, in PS-NP exposed met-2(RNAi) and set-6(RNAi) nematodes, expressions of ins-39, wrt-3, and/or efn-3 encoding secreted ligands were decreased. Therefore, our results demonstrated that inhibition in germline CED-1 mediated the toxicity induction of nanoplastics at ERCs across multiple generations in nematodes.

Size- and shape-dependent ingestion and acute toxicity of fragmented and spherical microplastics in the absence and presence of prey on two marine zooplankton

As microplastics (MPs) are particulate pollutants, their size and shape, and the presence of prey in the media can affect their toxicity. However, the size- and shape-dependent toxicities of MPs and their prey-dependent ingestion patterns in marine zooplankton are not well understood. Thus, we investigated the ingestion and egestion patterns, and toxicity of different shapes and sizes of MPs on two marine zooplankton, Brachionus koreanus and Diaphanosoma celebensis, under different prey conditions. The ingestion assay showed that smaller MPs were ingested more frequently, regardless of their shape. However, fragmented MPs showed higher toxicity than spherical MPs of comparable size. Prey in the media reduced the uptake and toxicity of MPs in both species depending on the taxa's feeding strategy. Our findings demonstrate that the size and shape of MPs are important factors in determining toxicity and that the presence of prey should also be considered when assessing MP toxicity.

Size-dependent effects of microplastics on intestinal microbiome for Perna viridis

Microplastics pollution threatens to marine organisms, particularly bivalves that actively ingest and accumulate microplastics of certain sizes, potentially disrupting intestinal homeostasis. This study investigated the microplastic abundance in wild and farmed mussels around Singapore, and examined the size-dependent effects of nano- to micro-scale polystyrene (0.5 µm/5 µm/50 µm) on the mussel intestinal microbiome in the laboratory. The field investigation revealed higher microplastic abundance in farmed mussels compared to wild ones. Experimentally, mussels exposed to 0.6 mg/L of microplastics for 7 days, followed by a 7-day depuration period, showed substantial impacts on Spirochaetes and Proteobacteria, facilitating the proliferation of pathogenic species and differentially affecting their pathogenic contributions. Metagenomics analysis revealed that microplastic exposure reduced Spirochaeta's contribution to virulence and pathogenicity loss, did not affect Vibrio and Oceanispirochaeta's pathogenicity, and increased Treponema and Oceanispirochaeta's contributions to pathogenicity loss. Moreover, microplastics increased transmembrane transporters and impacted oxidative phosphorylation enzymes, impairing energy metabolism. These effects persisted after depuration, indicating lack of resilience in the microbiome. Nano- and micro-scale plastics perturbed the mussel microbiome composition and functions in a size-dependent manner, with nano-plastics being the most disruptive. The increasing use and sale of aquaculture equipment of plastic may exacerbate the intestinal dysbiosis in bivalves, which threatens consumers' health.

Aged polystyrene microplastics cause reproductive impairment via DNA-damage induced apoptosis in Caenorhabditis elegans

Although polystyrene microplastics (PS-MPs) could induce toxic effects on environmental organisms, the toxicity of aged PS-MPs with H2O2 on soil organisms remains unclear. Our study utilized Caenorhabditis elegans as model organism to examine the reproductive toxicity of pristine PS-MPs (pPS-MPs) and aged PS-MPs (aPS-MPs) at environmentally relevant concentrations (0.1-100 μg/L). Acute exposure to aPS-MPs could induce greater reproductive impairment compared to pPS-MPs, as evidenced by changes in brood size and egg release. Assessment of gonad development using the number of mitotic cells, length of gonad arm, and relative area of gonad arm as parameters revealed a high reproductive toxicity caused by aPS-MPs exposure. Furthermore, aPS-MPs exposure promoted substantial germline apoptosis. Additionally, exposure to aPS-MPs (100 μg/L) markedly altered the expression of DNA damage-induced apoptosis-related genes (e.g., egl-1, cep-1, clk-2, ced-3, -4, and -9). Alterations in germline apoptosis caused by aPS-MPs were observed in mutants of cep-1, hus-1, egl-1, ced-3, -4, and -9. Consequently, the augmentation of reproductive toxicity resulting from aPS-MPs exposure was attributed to DNA damage-triggered cellular apoptosis. Additionally, the EGL-1-CEP-1-HUS-1-CED-3-CED-4-CED-9 signaling pathway was identified as a key regulator of germline apoptosis in nematodes. Our study provides insights into potential environmental risk of aPS-MPs with H2O2 on environmental organisms.

Effects of polystyrene microspheres on the swimming behavior and metabolism of grass carp (Ctenopharyngodon idella)

Microplastics (MPs) are a heterogeneous class of pollutants fouling aquatic environments and they are hazardous to aquatic organisms. This study investigated the size-dependent effects of polystyrene microspheres (PSMPs) on the swimming ability, metabolism, and oxidative stress of juvenile grass carp (Ctenopharyngodon idella). Test fish were exposed to four sizes of PSMPs (0.07, 0.5, 5, and 20-μm), and swimming ability was tested after different exposure times (2, 7, and 15 days). To measure the effect on swimming ability, critical swimming speed (Ucrit) was determined, and to assess metabolic effects, oxygen consumption (MO2), routine metabolic rate (RMR), maximum oxygen consumption (MMR), and excess post-exercise oxygen consumption (EPOC) were determined. To assess the effects on oxidative stress, the activities of two antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were determined in the liver and gills of test fish. After exposure to 20 μm PSMPs, there was a significant drop in Ucrit compared to the control group (P<0.05), with decreases of 22 % on Day 2 and Day 7, and 21 % on Day 15. The RMR and MMR increased significantly (P<0.05), the RMR by 23.9 % on Day 2 and the MMR by 17.2 % on Day 2 and on Day 15, 44.7 % and 20.0 % respectively. The EPOC decreased with exposure time, by 31 % (0.07-μm), 45 %-(0.5-μm), 49 % (5-μm), and 57 % (20-μm) after 15 days. Exposure to the larger PSMPs increased CAT and SOD activity more than the smaller PSMPs and the increases began with SOD activity in the gills. The larger PSMPs were consistently more harmful to juvenile grass carp than the smaller PSMPs. Our results clearly show that PSMPs have detrimental effects on juvenile grass carp and provide additional scientific evidence that environmental monitoring and regulation of microplastic pollution is necessary.

Micro and nanoplastics pollution: Sources, distribution, uptake in plants, toxicological effects, and innovative remediation strategies for environmental sustainability

Microplastics and nanoplastics (MNPs), are minute particles resulting from plastic fragmentation, have raised concerns due to their widespread presence in the environment. This study investigates sources and distribution of MNPs and their impact on plants, elucidating the intricate mechanisms of toxicity. Through a comprehensive analysis, it reveals that these tiny plastic particles infiltrate plant tissues, disrupting vital physiological processes. Micro and nanoplastics impair root development, hinder water and nutrient uptake, photosynthesis, and induce oxidative stress and cyto-genotoxicity leading to stunted growth and diminished crop yields. Moreover, they interfere with plant-microbe interactions essential for nutrient cycling and soil health. The research also explores the translocation of these particles within plants, raising concerns about their potential entry into the food chain and subsequent human health risks. The study underscores the urgency of understanding MNPs toxicity on plants, emphasizing the need for innovative remediation strategies such as bioremediation by algae, fungi, bacteria, and plants and eco-friendly plastic alternatives. Addressing this issue is pivotal not only for environmental conservation but also for ensuring sustainable agriculture and global food security in the face of escalating plastic pollution.

Floating microplastic pollution in the vicinity of a marine protected area and semi-enclosed bay of Peru

A baseline survey for floating microplastics (MPs) in the vicinity of a marine protected area and semi-enclosed bay of northern Peru was carried out. An average concentration of 0.22 MPs/L was estimated, primarily dominated by blue polyethylene terephthalate fibers. The distribution of floating MPs suggests that they tend to accumulate within the semi-enclosed Sechura Bay regardless of the sampling season. This behavior may be explained by local surface currents in the bay, which flow inwards and exhibit vorticities that could entrap MPs. Future studies are suggested to investigate the trajectory and fate of floating MPs within semi-enclosed areas. On the other hand, the impact of floating MPs on the trophic chain of coastal marine protected areas requires further research.

Comparison of Transgenerational Neurotoxicity between Pristine and Amino-Modified Nanoplastics in C. elegans

Increasing evidence has suggested that nanoplastic pollution has become a global concern. More importantly, transgenerational toxicity can be induced by nanoplastics at predicted environmentally relevant doses (ERDs). Considering that amino modification could increase nanoplastic toxicity, we compared transgenerational neurotoxicity between pristine polystyrene nanoparticle (PS-NP) and amino-modified PS-NP (NH2-PS-NP) in Caenorhabditis elegans. At 0.1-10 μg/L, NH2-PS-NP caused more severe transgenerational toxicity on locomotion and neuronal development. Accompanied with a difference in transgenerational neuronal damage, compared to PS-NP (10 μg/L), NH2-PS-NP (10 μg/L) induced more severe transgenerational activation of mec-4, crt-1, itr-1, and tra-3, which are required for the induction of neurodegeneration. Moreover, NH2-PS-NP (10 μg/L) caused more severe transgenerational inhibition in expressions of mpk-1, jnk-1, dbl-1, and daf-7 than PS-NP (10 μg/L), and RNA interference (RNAi) of these genes conferred susceptibility to the toxicity of PS-NP and NH2-PS-NP on locomotion and neuronal development. NH2-PS-NP (10 μg/L) further caused more severe transgenerational activation of germline ligand genes (ins-3, ins-39, daf-28, lin-44, egl-17, efn-3, and lag-2) than PS-NP (10 μg/L), and RNAi of these ligand genes caused resistance to the toxicity of PS-NP and NH2-PS-NP on locomotion and neuronal development. Our results highlighted more severe exposure risk of amino-modified nanoplastics at ERDs in causing transgenerational neurotoxicity in organisms.

Behavioral impairments and disrupted mitochondrial energy metabolism induced by polypropylene microplastics in zebrafish larvae

Polypropylene microplastics (PP-MPs) are emerging pollutant commonly detected in various environmental matrices and organisms, while their adverse effects and mechanisms are not well known. Here, zebrafish embryos were exposed to environmentally relevant concentrations of PP-MPs (0.08-50 mg/L) from 2 h post-fertilization (hpf) until 120 hpf. The results showed that the body weight was increased at 2 mg/L, heart rate was reduced at 0.08 and 10 mg/L, and behaviors were impaired at 0.4, 10 or 50 mg/L. Subsequently, transcriptomic analysis in the 0.4 and 50 mg/L PP-MPs treatment groups indicated potential inhibition on the glycolysis/gluconeogenesis and oxidative phosphorylation pathways. These findings were validated through alterations in multiple biomarkers related to glucose metabolism. Moreover, abnormal mitochondrial ultrastructures were observed in the intestine and liver in 0.4 and 50 mg/L PP-MPs treatment groups, accompanied by significant decreases in the activities of four mitochondrial electron transport chain complexes and ATP contents. Oxidative stress was also induced, as indicated by significantly increased ROS levels and significant reduced activities of CAT and SOD and GSH contents. All the results suggested that environmentally relevant concentrations of PP-MPs could induce disrupted mitochondrial energy metabolism in zebrafish, which may be associated with the observed behavioral impairments. This study will provide novel insights into PP-MPs-induced adverse effects and highlight need for further research.

Toxic effects of fragmented polyethylene terephthalate particles on the marine rotifer Brachionus koreanus: Based on ingestion and egestion assay, in vivo toxicity test, and multi-omics analysis

Microplastics (MPs) are a major concern in marine ecosystem because MPs are persistent and ubiquitous in oceans and are easily consumed by marine biota. Although many studies have reported the toxicity of MPs to marine biota, the toxicity of environmentally relevant types of MPs is little understood. We investigated the toxic effects of fragmented polyethylene terephthalate (PET) MP, one of the most abundant MPs in the ocean, on the marine rotifer Brachionus koreanus at the individual and molecular level. No significant rotifer mortality was observed after exposure to PET MPs for 24 and 48 h. The ingestion and egestion assays showed that rotifers readily ingested PET MPs in the absence of food but not when food was supplied; thus, there were also no chronic effects of PET MPs. In contrast, intracellular reactive oxygen species levels and glutathione S-transferase activity in rotifers were significantly increased by PET MPs. Transcriptomic and metabolomic analyses revealed that genes and metabolites related to energy metabolism and immune processes were significantly affected by PET MPs in a concentration-dependent manner. Although acute toxicity of PET MPs was not observed, PET MPs are potentially toxic to the antioxidant system, immune system, and energy metabolism in rotifers.

Research Progress on Micro(nano)plastic-Induced Programmed Cell Death Associated with Disease Risks

Due to their robust migration capabilities, slow degradation, and propensity for adsorbing environmental pollutants, micro(nano)plastics (MNPs) are pervasive across diverse ecosystems. They infiltrate various organisms within different food chains through multiple pathways including inhalation and dermal contact, and pose a significant environmental challenge in the 21st century. Research indicates that MNPs pose health threats to a broad range of organisms, including humans. Currently, extensive detection data and studies using experimental animals and in vitro cell culture indicate that MNPs can trigger various forms of programmed cell death (PCD) and can induce various diseases. This review provides a comprehensive and systematic analysis of different MNP-induced PCD processes, including pyroptosis, ferroptosis, autophagy, necroptosis, and apoptosis, based on recent research findings and focuses on elucidating the links between PCD and diseases. Additionally, targeted therapeutic interventions for these diseases are described. This review provides original insights into the opportunities and challenges posed by current research findings. This review evaluates ways to mitigate various diseases resulting from cell death patterns. Moreover, this paper enhances the understanding of the biohazards associated with MNPs by providing a systematic reference for subsequent toxicological research and health risk mitigation efforts.

Fetus Exposure to Drugs and Chemicals: A Holistic Overview on the Assessment of Their Transport and Metabolism across the Human Placental Barrier

BACKGROUND

The placenta exerts a crucial role in fetus growth and development during gestation, protecting the fetus from maternal drugs and chemical exposure. However, diverse drugs and chemicals (xenobiotics) can penetrate the maternal placental barrier, leading to deleterious, adverse effects concerning fetus health. Moreover, placental enzymes can metabolize drugs and chemicals into more toxic compounds for the fetus. Thus, evaluating the molecular mechanisms through which drugs and chemicals transfer and undergo metabolism across the placental barrier is of vital importance. In this aspect, this comprehensive literature review aims to provide a holistic approach by critically summarizing and scrutinizing the potential molecular processes and mechanisms governing drugs and chemical transfer and metabolism across the placental barrier, which may lead to fetotoxicity effects, as well as analyzing the currently available experimental methodologies used to assess xenobiotics placental transfer and metabolism.

METHODS

A comprehensive and in-depth literature review was conducted in the most accurate scientific databases such as PubMed, Scopus, and Web of Science by using relevant and effective keywords related to xenobiotic placental transfer and metabolism, retrieving 8830 published articles until 5 February 2024. After applying several strict exclusion and inclusion criteria, a final number of 148 relevant published articles were included.

RESULTS

During pregnancy, several drugs and chemicals can be transferred from the mother to the fetus across the placental barrier by either passive diffusion or through placental transporters, resulting in fetus exposure and potential fetotoxicity effects. Some drugs and chemicals also appear to be metabolized across the placental barrier, leading to more toxic products for both the mother and the fetus. At present, there is increasing research development of diverse experimental methodologies to determine the potential molecular processes and mechanisms of drug and chemical placental transfer and metabolism. All the currently available methodologies have specific strengths and limitations, highlighting the strong demand to utilize an efficient combination of them to obtain reliable evidence concerning drug and chemical transfer and metabolism across the placental barrier. To derive the most consistent and safe evidence, in vitro studies, ex vivo perfusion methods, and in vivo animal and human studies can be applied together with the final aim to minimize potential fetotoxicity effects.

CONCLUSIONS

Research is being increasingly carried out to obtain an accurate and safe evaluation of drug and chemical transport and metabolism across the placental barrier, applying a combination of advanced techniques to avoid potential fetotoxic effects. The improvement of the currently available techniques and the development of novel experimental protocols and methodologies are of major importance to protect both the mother and the fetus from xenobiotic exposure, as well as to minimize potential fetotoxicity effects.

A powerful method for In Situ and rapid detection of trace nanoplastics in water-Mie scattering

The pervasive presence of nanoplastics (NPs) in environmental media has raised significant concerns regarding their implications for environmental safety and human health. However, owing to their tiny size and low level in the environment, there is still a lack of effective methods for measuring the amount of NPs. Leveraging the principles of Mie scattering, a novel approach for rapid in situ quantitative detection of small NPs in low concentrations in water has been developed. A limit of detection of 4.2 μg/L for in situ quantitative detection of polystyrene microspheres as small as 25 nm was achieved, and satisfactory recoveries and relative standard deviations were obtained. The results of three self-ground NPs showed that the method can quantitatively detect the concentration of NPs in a mixture of different particle sizes. The satisfactory recoveries (82.4% to 110.3%) of the self-ground NPs verified the good anti-interference ability of the method. The total concentrations of the NPs in the five brands of commercial bottled water were 0.07 to 0.39 μg/L, which were directly detected by the method. The proposed method presents a potential approach for conducting in situ and real-time environmental risk assessments of NPs on human and ecosystem health in actual water environments.

Beyond the cradle - Amidst microplastics and the ongoing peril during pregnancy and neonatal stages: A holistic review

Advancements in research concerning the occurrence of microplastics (MPs) in human blood, sputum, urine, and breast milk samples have piqued the interest of the scientific community, prompting further investigation. MPs present in the placenta, amniotic fluid, and meconium raise concerns about interference with embryonic development, leading to preeclampsia, stillbirth, preterm birth, and spontaneous abortion. The challenges posed by MPs extend beyond pregnancy, affecting the digestive, reproductive, circulatory, immune, and central nervous systems. This has spurred scientists to examine the origins of MPs in distinct environmental layers, including air, water, and soil. These risks continue after birth, as neonates are continuously exposed to MPs through everyday items such as breast milk, cow milk and infant milk powder, as well as plastic-based products like feeding bottles and breast milk storage bags. It is the need of the hour to strike a balance amidst lifestyle changes, alternative choices to traditional plastic products, raising awareness about plastic-related health risks, and fostering collaboration between the scientific community and policymakers. This review aims to provide fresh insights into potential sources of MP pollution, with a specific focus on pregnancy and neonates. It is the first compilation of its kind so far that includes critical studies on recently reported discoveries.

Polyethylene terephthalate nanoplastics cause oxidative stress induced cell death in Saccharomyces cerevisiae

Polyethylene terephthalate (PET) is a common plastic widely used in food and beverage packaging that poses a serious risk to human health and the environment due to the continual rise in its production and usage. After being produced and used, PET accumulates in the environment and breaks down into nanoplastics (NPs), which are then consumed by humans through water and food sources. The threats to human health and the environment posed by PET-NPs are of great concern worldwide, yet little is known about their biological impacts. Herein, the smallest sized PET-NPs so far (56 nm) with an unperturbed PET structure were produced by a modified dilution-precipitation method and their potential cytotoxicity was evaluated in Saccharomyces cerevisiae. Exposure to PET-NPs decreased cell viability due to oxidative stress induction revealed by the increased expression levels of stress response related-genes as well as increased lipid peroxidation. Cell death induced by PET-NP exposure was mainly through apoptosis, while autophagy had a protective role.

Combined effects of norfloxacin and polystyrene nanoparticles on the oxidative stress and gut health of the juvenile horseshoe crab Tachypleus tridentatus

Pollution with anthropogenic contaminants including antibiotics and nanoplastics leads to gradual deterioration of the marine environment, which threatens endangered species such as the horseshoe crab Tachypleus tridentatus. We assessed the potential toxic mechanisms of an antibiotic (norfloxacin, 0, 0.5, 5 μg/L) and polystyrene nanoparticles (104 particles/L) in T. tridentatus using biomarkers of tissue redox status, molting, and gut microbiota. Exposure to single and combined pollutants led to disturbance of redox balance during short-term (7 days) exposure indicated by elevated level of a lipid peroxidation product, malondialdehyde (MDA). After prolonged (14-21 days) exposure, compensatory upregulation of antioxidants (catalase and glutathione but not superoxide dismutase) was observed, and MDA levels returned to the baseline in most experimental exposures. Transcript levels of molting-related genes (ecdysone receptor, retinoic acid X alpha receptor and calmodulin A) and a molecular chaperone (cognate heat shock protein 70) showed weak evidence of response to polystyrene nanoparticles and norfloxacin. The gut microbiota T. tridentatus was altered by exposures to norfloxacin and polystyrene nanoparticles shown by elevated relative abundance of Bacteroidetes. At the functional level, evidence of suppression by norfloxacin and polystyrene nanoparticles was found in multiple intestinal microbiome pathways related to the genetic information processing, metabolism, organismal systems, and environmental information processing. Future studies are needed to assess the physiological and health consequences of microbiome dysbiosis caused by norfloxacin and polystyrene nanoparticles and assist the environmental risk assessment of these pollutants in the wild populations of the horseshoe crabs.