Microplastics induce neurotoxicity in aquatic animals at environmentally realistic concentrations: A meta-analysis

In-situ detection of microplastics in the aquatic environment: A systematic literature review

Microplastics are ubiquitous in the aquatic environment and have emerged as a significant environmental issue due to their potential impacts on human health and the ecosystem. Current laboratory-based microplastic detection methods suffer from various drawbacks, including a lack of standardisation, limited spatial and temporal coverage, high costs, and time-consuming procedures. Consequently, there is a need for the development of in-situ techniques to detect and monitor microplastics to effectively identify and understand their sources, pathways, and behaviours. Herein, we adopt a systematic literature review method to assess the development and application of experimental and field technologies designed for the in-situ detection and monitoring of aquatic microplastics, without the need for sample preparation. Four scientific databases were searched in March 2023, resulting in a review of 62 relevant studies. These studies were classified into seven sensor categories and their working principles were discussed. The sensor classes include optical devices, digital holography, Raman spectroscopy, other spectroscopy, hyperspectral imaging, remote sensing, and other methods. We also looked at how data from these technologies are integrated with machine learning models to develop classifiers capable of accurately characterising the physical and chemical properties of microplastics and discriminating them from other particles. This review concluded that in-situ detection of microplastics in aquatic environments is feasible and can be achieved with high accuracy, even though the methods are still in the early stages of development. Nonetheless, further research is still needed to enhance the in-situ detection of microplastics. This includes exploring the possibility of combining various detection methods and developing robust machine-learning classifiers. Additionally, there is a recommendation for in-situ implementation of the reviewed methods to assess their effectiveness in detecting microplastics and identify their limitations.

Polystyrene nanoplastics cause reproductive toxicity in zebrafish: PPAR mediated lipid metabolism disorder

The ubiquitous presence of micro-and nanoplastics (MNPs) in the environment and everyday products has attracted attention due to their hazardous risks. However, the effects of MNPs on reproduction and the underlying mechanisms remain unclear. The present study investigated the impact of polystyrene (PS) nanoplastics of 80, 200 and 500 nm diameters on zebrafish reproduction at an environmentally relevant concentration of 0.5 mg/L. Exposure to PS delayed spermatogenesis and caused aberrant follicular growth, resulting in dysgenesis in F0 adults and impacting F1 embryo development. Notably, the reproductive toxicity exhibited size-dependency, with the 500 nm PS being the most detrimental. Combined analyses of transcriptomics and metabolomics in ovary tissue revealed that treatment with 500 nm PS affected the peroxisome proliferator-activated receptor (PPAR) signaling pathway, dysregulated lipid transport, binding and activity processes, and led to dysgenesis in zebrafish. Specifically, the ovulatory dysfunction induced by PS exposure resembled clinical manifestations of polycystic ovary syndrome (PCOS) and can be attributed to lipid metabolism disorder involving glycerophospholipid, sphingolipid, arachidonic acid, and alpha-linolenic acid. Collectively, our results provide new evidence revealing the molecular mechanisms of PS-induced reproductive toxicity, highlighting that MNPs may pose a risk to female reproductive health.

When antibiotics encounter microplastics in aquatic environments: Interaction, combined toxicity, and risk assessments

Antibiotics and microplastics (MPs), known as emerging pollutants, are bound to coexist in aquatic environments due to their widespread distribution and prolonged persistence. To date, few systematic summaries are available for the interaction between MPs and antibiotics in aquatic ecosystems, and a comprehensive reanalysis of their combined toxicity is also needed. Based on the collected published data, we have analyzed the source and distribution of MPs and antibiotics in global aquatic environments, finding their coexistence occurs in a lot of study sites. Accordingly, the presence of MPs can directly alter the environmental behavior of antibiotics. The main influencing factors of interaction between antibiotics and MPs have been summarized in terms of the characteristics of MPs and antibiotics, as well as the environmental factors. Then, we have conducted a meta-analysis to evaluate the combined toxicity of antibiotics and MPs on aquatic organisms and the related toxicity indicators, suggesting a significant adverse effect on algae, and inapparent on fish and daphnia. Finally, the environmental risk assessments for antibiotics and MPs were discussed, but unfortunately the standardized methodology for the risk assessment of MPs is still challenging, let alone assessment for their combined toxicity. This review provides insights into the interactions and environment risks of antibiotics and MPs in the aquatic environment, and suggests perspectives for future research.

Behavioral toxicity and neurotoxic mechanisms of PLA-PBAT biodegradable microplastics in zebrafish

Escalation of ecological concern due to biodegradable plastics has attracted the attention of many contemporary researchers. This study searched to investigate the acute and sub-chronic toxicity of polylactic acid (PLA) and polybutyleneadipate-co-terephthalate (PLA-PBAT) bio-microplastics on 3-month-old zebrafish to elucidate their potential toxic mechanisms. Acute toxicity assessments revealed 96 h-LC50 value of 12.69 mg/L for PLA-PBAT. Sub-chronic exposure of over 21 days revealed deviations in critical behavioral patterns and physiological indicators. In treated groups, weight gain and specific growth rates were significantly lower than those obtained for the control group, such that high doses induced significant reductions in total organ coefficient (p < 0.05). A positive correlation was observed between zebrafish mortality and increased doses. Detailed behavioral evaluations revealed a dose-dependent decrease in the speed and range of swimming, along with modifications in shoaling behavior, anxiety-like responses, and avoidance behaviors. Brain tissues transcriptomic analyses revealed the molecular responses underlying sub-chronic exposure to PLA-PBAT. Totally 702 DEGs and 5 KEGG pathways were significantly identified in low-dose group, with the top 2 significant pathways being ribosome pathway and cytokine-cytokine receptor interaction pathway. Totally 650 DEGs and 5 KEGG pathways were significantly identified in medium-dose group, with the top 2 significant pathways being Herpes simplex virus 1 infection pathway and complement and coagulation cascades pathway. Totally 1778 DEGs and 16 KEGG pathways were significantly identified in high-dose group, with the top 2 significant pathways being metabolism of xenobiotics by cytochrome P450 and drug metabolism - cytochrome P450 pathway. Most significantly enriched pathways are associated with immune responses. The validation of key gene in cytokine-cytokine receptor interaction pathway also confirmed its high correlation with behavioral indicators. These results indicate that PLA-PBAT is likely to cause behavioral abnormalities in zebrafish by triggering immune dysregulation in the brain.

Nanoplastics and Neurodegeneration in ALS

Plastic production, which exceeds one million tons per year, is of global concern. The constituent low-density polymers enable spread over large distances and micro/nano particles (MNPLs) induce organ toxicity via digestion, inhalation, and skin contact. Particles have been documented in all human tissues including breast milk. MNPLs, especially weathered particles, can breach the blood-brain barrier, inducing neurotoxicity. This has been documented in non-human species, and in human-induced pluripotent stem cell lines. Within the brain, MNPLs initiate an inflammatory response with pro-inflammatory cytokine production, oxidative stress with generation of reactive oxygen species, and mitochondrial dysfunction. Glutamate and GABA neurotransmitter dysfunction also ensues with alteration of excitatory/inhibitory balance in favor of reduced inhibition and resultant neuro-excitation. Inflammation and cortical hyperexcitability are key abnormalities involved in the pathogenic cascade of amyotrophic lateral sclerosis (ALS) and are intricately related to the mislocalization and aggregation of TDP-43, a hallmark of ALS. Water and many foods contain MNPLs and in humans, ingestion is the main form of exposure. Digestion of plastics within the gut can alter their properties, rendering them more toxic, and they cause gut microbiome dysbiosis and a dysfunctional gut-brain axis. This is recognized as a trigger and/or aggravating factor for ALS. ALS is associated with a long (years or decades) preclinical period and neonates and infants are exposed to MNPLs through breast milk, milk substitutes, and toys. This endangers a time of intense neurogenesis and establishment of neuronal circuitry, setting the stage for development of neurodegeneration in later life. MNPL neurotoxicity should be considered as a yet unrecognized risk factor for ALS and related diseases.

Microplastic contamination in wastewater: Sources, distribution, detection and remediation through physical and chemical-biological methods

Microplastics are tiny plastic particles smaller than 5 mm. that have been widely detected in the environment, including in wastewater. They originate from various sources including breakdown of larger plastic debris, release of plastic fibres from textiles, and microbeads commonly used in personal care products. In wastewater, microplastics can pass through the treatment process and enter the environment, causing harm to biodiversity by potentially entering the food chain. Additionally, microplastics can act as a vector for harmful pollutants, increasing their transport and distribution in the environment. To address this issue, there is a growing need for effective wastewater treatment methods that can effectively remove microplastics. Currently, several physical and chemical methods are available, including filtration, sedimentation, and chemical degradation. However, these methods are costly, low efficiency and generate secondary pollutants. Furthermore, lack of standardization in the measurement and reporting of microplastics in wastewater, makes it difficult to accurately assess microplastic impact on the environment. In order to effectively manage these issues, further research and development of effective and efficient methods for removing microplastics from wastewater, as well as standardization in measurement and reporting, are necessary to effectively manage these detrimental contaminants.

Polystyrene Nano- and Microplastic Particles Induce an Inflammatory Gene Expression Profile in Rat Neural Stem Cell-Derived Astrocytes In Vitro

Microplastics are considered an emerging environmental pollutant due to their ubiquitous presence in the environment. However, the potential impact of microplastics on human health warrants further research. Recent studies have reported neurobehavioral and neurotoxic effects in marine and rodent models; however, their impact on the underlying cellular physiology in mammals remains unclear. Herein, we exposed neural stem cells and neural stem cell-derived astrocytes, oligodendrocytes, and neurons to various sizes and concentrations of polystyrene nano- and microplastics. We investigated their cellular uptake, impact on cytotoxicity, and alteration of gene expression through transcriptome profiling. The cell type most affected by decreased viability were astrocytes after 7 days of repeated exposure. Transcriptional analysis showed that 1274 genes were differentially expressed in astrocytes exposed to 500 nm microplastics, but only 531 genes were altered in astrocytes exposed to 50 nm nanoplastics. Both canonical pathway and Kyoto Encyclopedia of Genes and Genomes analysis showed that upregulated pathways were involved in neuroinflammation, innate and adaptive immunity, cell migration, proliferation, extracellular matrix remodeling, and cytoskeleton structures. The downregulated pathways were involved in lipid metabolism, specifically fatty acid oxidation and cholesterol metabolism. Our results show that neural stem cell-derived astrocytes repeatedly exposed to nano- and microplastics for 7 days undergo changes that are hallmarks of astrogliosis.

Polystyrene nanoplastics induced size-dependent developmental and neurobehavioral toxicities in embryonic and juvenile zebrafish

Because of widespread environmental contamination, there is growing concern that nanoplastics may pose a risk to humans and the environment. Due to their small particle size, nanoplastics may cross the blood-nerve barrier and distribute within the nervous system. The present study systematically investigated the uptake/distribution and developmental/neurobehavioral toxicities of different sizes (80, 200, and 500 nm) of polystyrene nanoplastics (PS) in embryonic and juvenile zebrafish. The results indicate that all three sizes of PS could cross the chorion, adsorb by the yolk, and distribute into the intestinal tract, eye, brain, and dorsal trunk of zebrafish, but with different patterns. The organ distribution and observed developmental and neurobehavioral effects varied as a function of PS size. Although all PS exposures induced cell death and inflammation at the cellular level, only exposures to the larger PS resulted in oxidative stress. Meanwhile, exposure to the 80 nm PS increased the expression of neural and optical-specific mRNAs. Collectively, these studies indicate that early life-stage exposures to PS adversely affect zebrafish neurodevelopment and that the observed toxicities are influenced by particle size.

Microplastics cause hepatotoxicity in diabetic mice by disrupting glucolipid metabolism via PP2A/AMPK/HNF4A and promoting fibrosis via the Wnt/β-catenin pathway

In recent years, microplastics (MPs) have gained significant attention as a persistent environmental pollutant resulting from the decomposition of plastics, leading to their accumulation in the human body. The liver, particularly of individuals with type 2 diabetes mellitus (T2DM), is known to be more susceptible to the adverse effects of environmental pollutants. Therefore, to investigate the potential impact of MPs on the liver of diabetic mice and elucidate the underlying toxicological mechanisms, we exposed db/db mice to 0.5 μm MPs for 3 months. Our results revealed that MPs exposure resulted in several harmful effects, including decreased body weight, disruption of liver structure and function, elevated blood glucose levels, impaired glucose tolerance, and increased glycogen accumulation in the hepatic tissue of the mice. Furthermore, MPs exposure was found to promote hepatic gluconeogenesis by perturbing the PP2A/AMPK/HNF4A signaling pathway. In addition, MPs disrupt redox balance, leading to oxidative damage in the liver. This exposure also disrupted hepatic lipid metabolism, stimulating lipid synthesis while inhibiting catabolism, ultimately resulting in the development of fatty liver. Moreover, MPs were found to induce liver fibrosis by activating the Wnt/β-catenin signaling pathway. Furthermore, MPs influenced adaptive thermogenesis in brown fat by modulating the expression of uncoupling protein 1 (UCP1) and genes associated with mitochondrial oxidative respiration thermogenesis in brown fat. In conclusion, our study demonstrates that MPs induce oxidative damage in the liver, disturb glucose and lipid metabolism, promote hepatic fibrosis, and influence adaptive thermogenesis in brown fat in diabetic mice. These findings underscore the potential adverse effects of MPs on liver health in individuals with T2DM and highlight the importance of further research in this area.

Exposure to polystyrene nanoplastics and PCB77 induced oxidative stress, histopathological damage and intestinal microbiota disruption in white hard clam Meretrix lyrata

The toxic effects of organic pollutants and nanoplastics on fish have been extensively studied, but there is limited research available on their combined toxicity to bivalves. This research aimed to investigate the accumulation and ecotoxicological impacts such as antioxidant capacity, histopathology and intestinal microbiota in white hard clam Meretrix lyrata, resulting from 7 days of single and mixture exposure to 3,3',4,4'-tetrachlorobiphenyl (PCB77, 0.1 mg/L) and polystyrene nanoplastics (PS-NPs, 80 nm, 1 mg/L). Our findings revealed that PS-NPs accumulated in various tissues such as the intestine, gill, mantle, foot, and siphon. And when compared to the PCB-PSNPs (PP) co-exposure group, the intestinal fluorescence intensity mediated by plastic particles in the PS-NPs (PS group) was significantly higher. The gill, digestive gland, and intestine were all damaged to varying extent by single exposure to PS-NPs or PCB77, according to histopathological analysis, which was aggravated by PP group. Moreover, the co-exposure induced a higher level of oxidative stress, which reflected by increase of activities of superoxide dismutase, catalase, glutamate oxaloacetate transaminase and glutamic-pyruvic transaminase and malondialdehyde content. In addition, the intestine microbial composition was dramatically altered by the combined exposure, reducing the abundance of probiotics such as Firmicutes, thereby posing a great threat to the health and metabolism of M. lyrata. In conclusion, our findings showed that PS-NPs and PCB77 co-exposure induced a higher toxicity to M. lyrata, including histopathological changes, altered antioxidant capacity and intestinal microbiota disruption. This study provides novel insights into PCB77 and PS-NPs' combined toxicity to marine organisms and its underlying molecular mechanisms of ecotoxicological effects.

Size- and surface charge-dependent hormetic effects of microplastics on bacterial resistance and their interactive effects with quinolone antibiotic

The facilitation of microplastics (MPs) on bacterial resistance has attracted wide concern, due to the widespread presence of MPs in environmental media and their ubiquitous contact with bacteria strains. Furthermore, MPs possibly co-exist with antibiotics to trigger combined stress on bacterial survival. Therefore, it is significant to reveal the dose-responses of MPs and MP-antibiotic mixtures on bacterial endogenous and exogenous resistance. In this study, 0.1 and 5 μm polystyrenes with no surface functionalization (PS-NF, no charge), surface functionalized with amino groups (PS-NH2, positive charge) and carboxyl groups (PS-COOH, negative charge) were selected as the test MPs, and norfloxacin (NOR) was set as the representative of antibiotics. It was found that six types of PS all inhibited the growth of Escherichia coli (E. coli) but induced hormetic dose-responses on the mutation frequency (MF) and conjugative transfer frequency (CTF) of RP4 plasmid in E. coli. Moreover, these hormetic effects exhibited size- and surface charge-dependent features, where 0.1 μm PS-NH2 (100 mg/L) triggered the maximum stimulatory rates on MF (363.63 %) and CTF (74.80 %). The hormetic phenomena of MF and CTF were also observed in the treatments of PS-NOR mixtures, which varied with the particle size and surface charge of PS. In addition, the interactive effects between PS and NOR indicated that the co-existence of PS and NOR might trigger greater resistance risk than the single pollutants. Mechanistic exploration demonstrated that the increase of cellular reactive oxygen species and the variation of cell membrane permeability participated in the hormetic effects of PS and PS-NOR mixtures on bacterial resistance. This study provides new insights into the individual effects of MPs and the combined effects of MP-antibiotic mixtures on bacterial resistance, which will promote the development of environmental risk assessment of MPs from the perspective of bacterial resistance.

Combined effects of a high-fat diet and polyethylene microplastic exposure induce impaired lipid metabolism and locomotor behavior in larvae and adult zebrafish

Microplastics (MP), tiny plastic particles, can be ingested by fish through their habitat or contaminated food sources. When combined with a high-fat diet (HFD), MP exposure may lead to increased MP accumulation in fish and negative impacts on their health. However, the underlying mechanisms of how MP and HFD interact to promote fat accumulation in fish remain poorly understood. In this study, we aimed to evaluate the combined effect of HFD and polyethylene MP (PE-MP) in the zebrafish model (Danio rerio) and decipher its molecular mechanisms. Adult zebrafish exposed to the combined HFD and PE-MP showed elevated lipid accumulation, total cholesterol, triglycerides, and abnormal swimming behavior compared to HFD-fed fish. Histological and gene expression analysis revealed severe hepatic inflammation and injury, resembling nonalcoholic fatty liver disease (NAFLD) in the HFD + PE-MP exposed zebrafish. Moreover, HFD and PE-MP exposure upregulated genes related to lipogenesis (SREBP1, FAS, and C/EBPα) and inflammation (tnfα, il1β, and il-6) in the liver. These findings underscore the interactive effect of environmental pollutants and fish diet, emphasizing the importance of improving fish culture practices to safeguard fish health and human consumers from microplastic contamination through the food chain. This research sheds light on the complex interactions between microplastics and diet, providing valuable insights into the potential risks of microplastic pollution in aquatic ecosystems and the implications for human health. Understanding the underlying molecular mechanisms will contribute to international research efforts to mitigate the adverse effects of microplastics on both environmental and public health.

Prolonged exposure to environmental levels of microcystin-LR triggers ferroptosis in brain via the activation of Erk/MAPK signaling pathway

While existing research has illuminated the environmental dangers and neurotoxic effects of MC-LR exposure, the molecular underpinnings of brain damage from environmentally-relevant MC-LR exposure remain elusive. Employing a comprehensive approach involving RNA sequencing, histopathological examination, and biochemical analyses, we discovered genes differentially expressed and enriched in the ferroptosis pathway. This finding was associated with mitochondrial structural impairment and downregulation of Gpx4 and Slc7a11 in mice brains subjected to low-dose MC-LR over 180 days. Mirroring these findings, we noted reduced cell viability and GSH/GSSH ratio, along with an increased ROS level, in HT-22, BV-2, and bEnd.3 cells following MC-LR exposure. Intriguingly, MC-LR also amplified phospho-Erk levels in both in vivo and in vitro settings, and the effects were mitigated by treatment with PD98059, an Erk inhibitor. Taken together, our findings implicate the activation of the Erk/MAPK signaling pathway in MC-LR-induced ferroptosis, shedding valuable light on the neurotoxic mechanisms of MC-LR. These insights could guide future strategies to prevent MC-induced neurodegenerative diseases.

Teratogenic effects of environmental concentration of plastic particles on freshwater organisms

Given the widespread presence of plastics, especially in micro- and nanoscale sizes, in freshwater systems, it is crucial to identify a suitable model organism for assessing the potential toxic and teratogenic effects of exposure to plastic particles. Until now, the early life stage of freshwater organisms and the regeneration capacity in relation to plastic particles exposure is a still poorly investigated topic. In this study, we examine the teratogenic effect on diatom Cocconeis placentula and cnidarian Hydra vulgaris under controlled exposure conditions of poly(styrene-co-methyl methacrylate) (P(S-co-MMA)) particles. Significant effects were observed at the lowest concentrations (0.1 μg/L). A significant increase in the teratological frequency in C. placentula and a significant decrease in the regeneration rate in H. vulgaris were found at the lowest concentration. The delay in hydra regeneration impaired the feeding capacity and tentacles reactivity at 96 h of exposure. No effects on diatom growth were observed upon exposure to P(S-co-MMA) particles (0.1, 1, 100, 10,000 μg/L) for 28 days and these findings agree with other studies investigating algal growth. The application of the Teratogenic Risk Index, modified for diatoms, highlighted a moderate risk for the lowest concentration evaluating C. placentula and low risk at the lowest and the highest concentrations considering H. vulgaris. This study suggests the importance of testing organisms belonging to different trophic levels as diverse teratogenic effects can be found and the need to evaluate environmentally relevant concentrations of plastic particles.

The neurodevelopmental toxicity induced by combined exposure of nanoplastics and penicillin in embryonic zebrafish: The role of aging processes

As ubiquitous contaminants, nanoplastics and antibiotics are frequently co-presence and widely detected in the freshwater environment and biota, posing a high co-exposure risk to aquatic organisms and even humans. More importantly, how the aging process of nanoplastics affects the joint toxic potential of nanoplastics and antibiotics has not been explored. Here, we generated two aged polystyrene nanoplastics (PS) by UV radiation (UV-PS) and ozonation (O3-PS). Non-teratogenic concentrations of pristine PS (80 nm) and antibiotics penicillin (PNC) co-exposure synergistically suppressed the embryo heart beating and behaviors of spontaneous movement, touch response, and larval swimming behavioral response. Pristine PS and aged UV-PS, but not aged O3-PS, showed similar effects on zebrafish embryo/larval neurodevelopment. However, when co-exposure with PNC, both aged PS, but not pristine PS, showed antagonistic effects. In late-stage juvenile social behavior testing, we found that PS decreased the exploration in light/dark preference assay. The synergistic effect of aged PS with PNC was further explored, including cellular apoptosis, ROS formation, and neurotransmitter metabolite regulation. Mechanistically, aged UV-PS but not O3-PS significantly increased the adsorption rate of PNC compared to pristine PS, which may account for the toxicity difference between the two aged PS. In conclusion, our results confirmed that PS served as a carrier for PNC, and the environmental aging process changed their neurobehavioral toxicity pattern in vivo.

Sources, Degradation, Ingestion and Effects of Microplastics on Humans: A Review

Celluloid, the predecessor to plastic, was synthesized in 1869, and due to technological advancements, plastic products appear to be ubiquitous in daily life. The massive production, rampant usage, and inadequate disposal of plastic products have led to severe environmental pollution. Consequently, reducing the employment of plastic has emerged as a pressing concern for governments globally. This review explores microplastics, including their origins, absorption, and harmful effects on the environment and humans. Several methods exist for breaking down plastics, including thermal, mechanical, light, catalytic, and biological processes. Despite these methods, microplastics (MPs, between 1 and 5 mm in size) continue to be produced during degradation. Acknowledging the significant threat that MPs pose to the environment and human health is imperative. This form of pollution is pervasive in the air and food and infiltrates our bodies through ingestion, inhalation, or skin contact. It is essential to assess the potential hazards that MPs can introduce. There is evidence suggesting that MPs may have negative impacts on different areas of human health. These include the respiratory, gastrointestinal, immune, nervous, and reproductive systems, the liver and organs, the skin, and even the placenta and placental barrier. It is encouraging to see that most of the countries have taken steps to regulate plastic particles. These measures aim to reduce plastic usage, which is essential today. At the same time, this review summarizes the degradation mechanism of plastics, their impact on human health, and plastic reduction policies worldwide. It provides valuable information for future research on MPs and regulatory development.

Interactive effects of polystyrene nanoplastics and 6:2 chlorinated polyfluorinated ether sulfonates on the histomorphology, oxidative stress and gut microbiota in Hainan Medaka (Oryzias curvinotus)

Nanoplastics adsorb surrounding organic contaminants in the environment, which alters the physicochemical properties of contaminants and affects associated ecotoxicological effects on aquatic life. The current work aims to explore the individual and combined toxicological implications of polystyrene nanoplastics (80 nm) and 6:2 chlorinated polyfluorinated ether sulfonate (Cl-PFAES, trade name: F-53B) in an emerging freshwater fish model Hainan Medaka (Oryzias curvinotus). Therefore, O. curvinotus were exposed to 200 μg/L of PS-NPs or 500 μg/L of F-53B in the single or mixture exposure for 7 days to investigate the effects on fluorescence accumulation, tissue damage, antioxidant capacity and intestinal flora. The PS-NPs fluorescence intensity was significantly higher in the single exposure treatment than it in combined exposure treatment (p < 0.01). Histopathological results showed that exposure to PS-NPs or F-53B inflicted varying degree of damages to the gill, liver, and intestine, and these damage were also present in the corresponding tissues of the combined treatment group, illustrating a stronger extent of destruction of these tissues by the combined treatment. Compared to the control group, combined exposure group elevated the malondialdehyde (MDA) content, superoxide dismutase (SOD) and catalase (CAT) activities except in the gill. In addition, the adverse contribution of PS-NPs and F-53B on the enteric flora in the single and combined exposure groups was mainly characterised in the form of reductions in the number of probiotic bacteria (Firmicutes) and this reduction was aggravated by the combined exposure group. Collectively, our results indicated that the toxicological effects of PS-NPs and F-53B on pathology, antioxidant capacity and microbiomics of medaka may be modulated by the interaction of two contaminants with mutually interactive effects. And our work offers fresh information on the combined toxicity of PS-NPs and F-53B to aquatic creatures along with a molecular foundation for the environmental toxicological mechanism.