Single and repetitive microplastics exposures induce immune system modulation and homeostasis alteration in the edible mussel Mytilus galloprovincialis

Plastic pollution and marine mussels: Unravelling disparities in research efforts, biological effects and influences of global warming

The ever-growing contamination of the environment by plastics is a major scientific and societal concern. Specifically, the study of microplastics (1 μm to 5 mm), nanoplastics (< 1 μm), and their leachates is a critical research area as they have the potential to cause detrimental effects, especially when they impact key ecological species. Marine mussels, as ecosystem engineers and filter feeders, are particularly vulnerable to this type of pollution. In this study, we reviewed the 106 articles that focus on the impacts of plastic pollution on marine mussels. First, we examined the research efforts in terms of plastic characteristics (size, polymer, shape, and leachates) and exposure conditions (concentration, duration, species, life stages, and internal factors), their disparities, and their environmental relevance. Then, we provided an overview of the effects of plastics on mussels at each organisational levels, from the smaller scales (molecular, cellular, tissue and organ impacts) to the organism level (functional, physiological, and behavioural impacts) as well as larger-scale implications (associated community impacts). We finally discussed the limited research available on multi-stressor studies involving plastics, particularly in relation to temperature stress. We identified temperature as an underestimated factor that could shape the impacts of plastics, and proposed a roadmap for future research to address their combined effects. This review also highlights the impact of plastic pollution on mussels at multiple levels and emphasises the strong disparities in research effort and the need for more holistic research, notably through the consideration of multiple stressors, with a specific focus on temperature which is likely to become an increasingly relevant forcing factor in an era of global warming. By identifying critical gaps in current knowledge, we advocate for more coordinated interdisciplinary and international collaborations and raise awareness of the need for environmental coherence in the choice and implementation of experimental protocols.

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.

Omics insights in responses of bivalves exposed to plastic pollution

Plastic pollution, particularly microplastics and nanoplastics, poses a significant threat to marine ecosystems. Bivalves, vital filter feeders that accumulate plastic particles, underscore the necessity for advanced omics technologies to grasp their molecular reactions to plastic exposure. This review delves into the impact of microplastics and nanoplastics on bivalves utilizing advanced omics technologies. Through an examination of omics data, this review sheds light on how bivalves react to plastic pollution, informing strategies for conservation and food safety. Furthermore, theoretical pathways have been formulated to decipher how bivalves respond to environmental stressors from microplastics or nanoplastics through the integration of diverse biological fields. In this review, we report that microplastics and nanoplastics in marine ecosystems primarily stem from human activities on land and in marine domains. Bivalves are negatively influenced by plastic contamination, impacting their health and economic worth. Exposure to plastic particles disrupts bivalve behavior, metabolism, and reproduction, precipitating health concerns. Integration of omics data is instrumental in unraveling molecular interactions and devising biomarkers for monitoring purposes. Ingestion of plastics by bivalves poses risks to human health. Additionally, mitigation tactics involve bans, levies, and advocating for biodegradable alternatives to curtail plastic pollution. The amalgamation of omics findings aids in the comprehension of bivalve responses and effectively addressing plastic pollution. Moreover, addressing plastic pollution necessitates a multidisciplinary approach encompassing scientific inquiry, regulatory frameworks, and collaboration with stakeholders. These strategies are paramount in safeguarding bivalves, marine ecosystems, food safety, and human health.

Biotransport and toxic effects of micro- and nanoplastics in fish model and their potential risk to humans: A review

The growing body of scientific evidence suggests that micro- and nanoplastics (MPs/NPs) pose a significant threat to aquatic ecosystems and human health. These particles can enter organisms through ingestion, inhalation, dermal contact, and trophic transfer. Exposure can directly affect multiple organs and systems (respiratory, digestive, neurological, reproductive, urinary, cardiovascular) and activate extensive intracellular signaling, inducing cytotoxicity involving mechanisms such as membrane disruption, extracellular polymer degradation, reactive oxygen species (ROS) production, DNA damage, cellular pore blockage, lysosomal instability, and mitochondrial depolarization. This review focuses on current research examining the in vivo and in vitro toxic effects of MPs/NPs on aquatic organisms, particularly fish, in relation to particulate toxicity aspects (such as particle transport mechanisms and structural modifications). Meanwhile, from the perspectives of the food chain and environmental factors, it emphasizes the comprehensive threats of MPs/NPs to human health in terms of both direct and indirect toxicity. Additionally, future research needs and strategies are discussed to aid in mitigating the potential risks of particulate plastics as carriers of toxic trace elements to human health.

Effects of tire particles and associated-chemicals on the Pacific oyster (Magallana gigas) physiology, reproduction and next-generation

By 2040, tire particles (TP) are expected to dominate marine plastic contamination, raising concerns about their effects on marine animals. This study employed a multidisciplinary and multigenerational approach on the Pacific oyster Magallana gigas to investigate the effects of TP and their leachates (LEA). Effects were analyzed at the individual scale, from cellular, molecular, and microbiota changes to reproductive outputs and offspring performance. Microbiota characterization revealed potential dysbiosis in oysters treated with high concentration of both TP and LEA. RNA-seq analyses highlighted the activation of energy metabolism and stress responses in the LEA treatment. Additionally, transcriptional changes in oocytes and the reduction of motile spermatozoa suggested potential effects on gamete quality. Notably, possible oyster resilience was pointed out by the lack of significant ecophysiological modifications in adults and impacts on the growth and reproductive outputs of the offspring. Overall, the implications of the observed oyster resilience under our experimental setting are discussed in relation to available toxicity data and within a comprehensive view of coastal ecosystems, where a higher diversity of plastic/rubber materials and harsher environmental conditions occur.

Microplastic pollution in commercially important edible marine bivalves: A comprehensive review

Microplastics have become major pollutants in the marine environment and can accumulate in high concentrations, especially in the gut of marine organisms. Unlike other seafood, bivalves are consumed whole, along with their digestive systems, resulting in the transfer of microplastics to humans. Therefore, there is an urgent need to review the status of microplastic pollution in marine bivalves. In this context, this article provides a comprehensive review of the status of microplastic pollution in marine bivalves and the impact of microplastics on the physiology and immunology of marine bivalves. In general, marine bivalves can accumulate high levels of microplastics in a tissue-specific manner. Although microplastic pollution does not cause mortality in bivalves, it can adversely affects bivalves' immunity, byssus production, and reproduction, potentially affecting bivalve populations. This article provides important information that will aid establishing management measures and determining the direction of future research.

Natural sea water and artificial sea water are not equivalent in plastic leachate contamination studies

Background

Plastic contamination is one of the concerns of our age. With more than 150 million tons of plastic floating in the oceans, and a further 8 million tons arriving to the water each year, in recent times the scientific community has been studying the effects these plastics have on sea life both in the field and with experimental approaches. Laboratory based studies have been using both natural sea water and artificial sea water for testing various aspects of plastic contamination, including the study of chemicals leached from the plastic particles to the water. We set out to test this equivalence, looking at the leaching of heavy metals form plastic particles.

Methods

We obtained leachates of polyvinyl chloride plastic pre-production nurdles both in natural and artificial sea water and determined the elements in excess from untreated water by Inductively coupled plasma - optical emission spectrometry. We then used these different leachates to assess developmental success in the tunicate Ciona intestinalis by treating fertilised eggs through their development to hatched larvae.

Results

Here we report that chemical analysis of polyvinyl chloride plastic pre-production pellet leachates shows a different composition in natural and artificial sea water. We find that the zinc leaching from the plastic particles is up to five times higher in natural seawater than in artificial seawater, and this can have an effect in the toxicological studies derived. Indeed, we observe different effects in the development of C. intestinalis when using leachates in natural or artificial sea water. We also observe that not all artificial sea waters are suitable for studying the development of the tunicate C. intestinalis.

Conclusions

Our results show that, at least in this case, both types of water are not equivalent to produce plastic leachaetes and suggest that precaution should be taken when conclusions are derived from results obtained in artificial sea water.

Unveiling the ecotoxicological impact of microplastics on organisms - the persistent organic pollutant (POP): A comprehensive review

Microplastics have been ubiquitous in our environment for decades, and numerous studies have revealed their extensive dispersion, reaching far beyond the surface of the land, soil, aquatic ecosystems. They have infiltrated the food-chain, the food web, even the air we breathe, as well as the water we drink. Microplastics have been detected in the food we consume, acting as vectors for hazardous chemicals that adhere to their hydrophobic surfaces. This can result in the transfer of these chemicals to the aquatic life, posing a threat to their well-being. The release of microplastics into different environmental settings can give rise to various eco-toxicological implications. The substantial body of literature has led scientists to the consensus that microplastic pollution is a global problem with the potential to impact virtually any type of ecosystem. This paper aims to discuss crucial information regarding the occurrence, accumulation, and ecological effects of microplastics on organisms. It also highlights the new and emerging disease named "Plasticosis" that is directly linked to microplastics and its toxicological effects like permanent scarring and long-term inflammation in the digestive system of the seabirds. By comprehending the behaviour of these microplastic pollutants in diverse habitats and evaluating their ecological consequences, it becomes possible to facilitate a better understanding of this toxicological issue.

Synthesis and characterization of micro-sized polyisobutylene and evaluation of its toxicological effects on the development and homeostasis of zebrafish (Danio rerio)

Rampant industrialization has led to widespread reliance on hydrocarbon polymers for various commercial applications. While these synthetic polymers, commonly known as plastics, degrade in slowly in the environments, the toxic effects of their micro-sized particles remain underexplored. In this study, we synthesized polyisobutylene (PIB) microparticles in the lab and evaluated their toxicity and accumulation in a zebrafish model. Pristine and fluorescent PIB-microplastics (MPs), with particle sizes ranging from 2 to 10 μm, were synthesized using the solvent evaporation method. Fourier-transform infrared spectroscopy (FTIR) confirmed the stability of the suspensions. Zebrafish larvae exposed to various concentrations of PIB-MPs exhibited numerous morphological and molecular changes, including delayed hatching, impaired swimming behavior, increased reactive oxygen species levels, altered mRNA levels of genes encoding antioxidant proteins, and reduced survival rates. Dissections revealed PIB-MP accumulation in the guts of larvae and adult fish within 7-21 days, causing damage to the intestinal mucosa. These findings provide insights into how contaminants like PIB can induce pathophysiological defects in aquatic fauna and pose potential health hazards to humans.

Microplastics contamination in the most popular brands of Iranian sausages and evaluation of its human exposure

Microplastics (MPs) pollution represents a nascent environmental contaminant that has recently infiltrated human life and the food chain. The primary objective of this study was to investigate the presence of MPs in different brands of Iranian sausages. Qualitative and quantitative analyses of MPs particles were conducted using stereo- and fluorescent microscopy, FT-IR (Fourier-transform infrared spectroscopy), and SEM-EDS (Scanning electron microscopy-energy dispersive X-ray spectroscopy) techniques. Samples were collected from the most commonly consumed sausage brands in Iranian markets. The findings showed that the various sausage brands contained an average abundance of 25.7 ± 21.68 (range 10-70) and 55.45 ± 45.5 (range 10-175) particles/kg based on optical and fluorescent microscopy analyses, respectively. Predominantly, MPs were identified in fiber form (77-89 %), with a smaller proportion present in fragmented form (11-23 %). Polymer analysis using FT-IR identified polyethylene (PE) and polystyrene (PS) as the primary constituents. Furthermore, the estimated annual intake (EAI) of MPs was calculated at 804 and 3517 particles/kg bw/year for adults and children, respectively, based on optical microscopy observations. In comparison, fluorescent microscopy indicated an intake of 1734 and 7589 particles/kg bw/year for the respective age groups. These results emphasize the potential of MPs contamination to penetrate into different food products including sausages through processing routes, which can threaten human health.

Decoding the molecular concerto: Toxicotranscriptomic evaluation of microplastic and nanoplastic impacts on aquatic organisms

The pervasive and steadily increasing presence of microplastics/nanoplastics (MPs/NPs) in aquatic environments has raised significant concerns regarding their potential adverse effects on aquatic organisms and their integration into trophic dynamics. This emerging issue has garnered the attention of (eco)toxicologists, promoting the utilization of toxicotranscriptomics to unravel the responses of aquatic organisms not only to MPs/NPs but also to a wide spectrum of environmental pollutants. This review aims to systematically explore the broad repertoire of predicted molecular responses by aquatic organisms, providing valuable intuitions into complex interactions between plastic pollutants and aquatic biota. By synthesizing the latest literature, present analysis sheds light on transcriptomic signatures like gene expression, interconnected pathways and overall molecular mechanisms influenced by various plasticizers. Harmful effects of these contaminants on key genes/protein transcripts associated with crucial pathways lead to abnormal immune response, metabolic response, neural response, apoptosis and DNA damage, growth, development, reproductive abnormalities, detoxification, and oxidative stress in aquatic organisms. However, unique challenge lies in enhancing the fingerprint of MPs/NPs, presenting complicated enigma that requires decoding their specific impact at molecular levels. The exploration endeavors, not only to consolidate existing knowledge, but also to identify critical gaps in understanding, push forward the frontiers of knowledge about transcriptomic signatures of plastic contaminants. Moreover, this appraisal emphasizes the imperative to monitor and mitigate the contamination of commercially important aquatic species by MPs/NPs, highlighting the pivotal role that regulatory frameworks must play in protecting all aquatic ecosystems. This commitment aligns with the broader goal of ensuring the sustainability of aquatic resources and the resilience of ecosystems facing the growing threat of plastic pollutants.

Potential threats of microplastics and pathogenic bacteria to the immune system of the mussels Mytilus galloprovincialis

As one of the main components of marine pollution, microplastics (MPs) inevitably enter the mussel aquaculture environment. At the same time, pathogenic bacteria, especially pathogens such as Vibrio, can cause illness outbreaks, leading to large-scale death of mussels. The potential harm of MPs and pathogenic bacteria to bivalve remains unclear. This study designed two experiments (1) mussels (Mytilus galloprovincialis) were exposed to 100 particles/L or 1,000 particles/L polymethyl methacrylate (PMMA, 17.01 ± 6.74 μm) MPs and 1 × 107 CFU/mL Vibrio parahaemolyticus at the same time (14 days), and (2) mussels were exposed to 100 particles/L or 1,000 particles/L MPs for a long time (30 days) and then exposed to 1 × 107 CFU/mL V. parahaemolyticus to explore the effects of these two stresses on the mussel immune system. The results showed that after the combined exposure of V. parahaemolyticus and MPs, the lysosomal membrane stability of hemocytes decreased, lysozyme activity was inhibited, and hemocytes were induced to produce more lectins and defensins to fight pathogenic invasion. Long-term exposure to MPs caused a large amount of energy consumption in mussels, inhibited most of the functions of humoral immunity, increased the risk of mussel infection with pathogenic bacteria, and negatively affected mussel condition factor, the number of hemocytes, and the number of byssuses. Mussels may allocate more energy to deal with MPs and pathogenic bacterial infections rather than for growth. Above all, MPs exposure can affect mussel immune function or reduce its stress resistance, which in turn has an impact on mollusk farming.

Navigating the nexus: climate dynamics and microplastics pollution in coastal ecosystems

Microplastics (MPs) pollution is an emerging environmental health concern, impacting soil, plants, animals, and humans through their entry into the food chain via bioaccumulation. Human activities such as improper solid waste dumping are significant sources that ultimately transport MPs into the water bodies of the coastal areas. Moreover, there is a complex interplay between the coastal climate dynamics, environmental factors, the burgeoning issue of MPs pollution and the complex web of coastal pollution. We embark on a comprehensive journey, synthesizing the latest research across multiple disciplines to provide a holistic understanding of how these inter-connected factors shape and reshape the coastal ecosystems. The comprehensive review also explores the impact of the current climatic patterns on coastal regions, the intricate pathways through which MPs can infiltrate marine environments, and the cascading effects of coastal pollution on ecosystems and human societies in terms of health and socio-economic impacts in coastal regions. The novelty of this review concludes the changes in climate patterns have crucial effects on coastal regions, proceeding MPs as more prevalent, deteriorating coastal ecosystems, and hastening the transfer of MPs. The continuous rising sea levels, ocean acidification, and strong storms result in habitat loss, decline in biodiversity, and economic repercussion. Feedback mechanisms intensify pollution effects, underlying the urgent demand for environmental conservation contribution. In addition, the complex interaction between human, industry, and biodiversity demanding cutting edge strategies, innovative approaches such as remote sensing with artificial intelligence for monitoring, biobased remediation techniques, global cooperation in governance, policies to lessen the negative socioeconomic and environmental effects of coastal pollution.

Characterization of the transcriptional effects of the plastic additive dibutyl phthalate alone and in combination with microplastic on the green-lipped mussel Perna canaliculus

The presence and persistence of microplastics (MPs) in diverse aquatic environments are of global concern. Microplastics can impact marine organisms via direct physical interaction and the release of potentially harmful chemical additives incorporated into the plastic. These chemicals are physically bound to the plastic matrix and can leach out. The hazards associated with chemical additives to exposed organisms is not well characterized. We investigated the hazards of plastic additives leaching from plastic. We used the common plasticizer dibutyl phthalate (DBP) as a chemical additive proxy and the New Zealand green-lipped mussel (Perna canaliculus) as a model. We used early-adult P. canaliculus exposed to combinations of virgin and DBP-spiked polyvinyl chloride (PVC), MPs, and DBP alone for 7 days. Whole transcriptome sequencing (RNA-seq) was conducted to assess whether leaching of DBP from MPs poses a hazard. The differences between groups were evaluated using pairwise permutational multivariate analysis of variance (PERMANOVA), and all treatments were significantly different from controls. In addition, a significant difference was seen between DBP and PVC MP treatment. Transcriptome analysis revealed that mussels exposed to DBP alone had the most differentially expressed genes (914), followed by PVC MP + DBP (448), and PVC MP (250). Gene ontology functional analysis revealed that the most enriched pathway types were in cellular metabolism, immune response, and endocrine disruption. Microplastic treatments enriched numerous pathways related to cellular metabolism and immune response. The combined exposure of PVC MP + DBP appears to cause combined effects, suggesting that DBP is bioavailable to the exposed mussels in the PVC MP + DBP treatment. Our results support the hypothesis that chemical additives are potentially an important driver of MP toxicity. Environ Toxicol Chem 2024;43:1604-1614. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The Plasticene era: Current uncertainties in estimates of the hazards posed by tiny plastic particles on soils and terrestrial invertebrates

Plastics are ubiquitous in our daily life. Large quantities of plastics leak in the environment where they weather and fragment into micro- and nanoparticles. This potentially releases additives, but rarely leads to a complete mineralization, thus constitutes an environmental hazard. Plastic pollution in agricultural soils currently represents a major challenge: quantitative data of nanoplastics in soils as well as their effects on biodiversity and ecosystem functions need more attention. Plastic accumulation interferes with soil functions, including water dynamics, aeration, microbial activities, and nutrient cycling processes, thus impairing agricultural crop yield. Plastic debris directly affects living organisms but also acts as contaminant vectors in the soils, increasing the effects and the threats on biodiversity. Finally, the effects of plastics on terrestrial invertebrates, representing major taxa in abundance and diversity in the soil compartment, need urgently more investigation from the infra-individual to the ecosystem scales.

Different recovery patterns of the surviving bivalve Mytilus galloprovincialis based on transcriptome profiling exposed to spherical or fibrous polyethylene microplastics

Microplastics (MPs) are pervasive pollutants exuded from anthropogenic activities and ingested by animals in different ecosystems. This transcriptomic profiling study aimed to explore the impact of polyethylene MPs on Mytilus galloprovincialis, an ecologically significant bivalve species. The toxicity of two MPs types was found to result in increased cellular stress when exposed up to 14 days. Moreover, recovery mechanisms were also observed in progress. Mussels exhibited different gene expression patterns and molecular regulation in response to cellular reactive oxygen species (ROS) stress. The transcriptome analysis demonstrated a notable hindrance in cilia movement as MPs ingested through gills. Subsequent entry resulted in a significant disruption in the cytoskeletal organization, cellular projection, and cilia beat frequency. On day 4 (D4), signal transduction and activation of apoptosis evidenced the signs of toxic consequences. Mussels exposed to spherical MPs shown significant recovery on day 14 (D14), characterized by the upregulation of anti-apoptotic genes and antioxidant genes. The expression of P53 and BCL2 genes was pivotal in controlling the apoptotic process and promoting cell survival. Mussels exposed to fibrous MPs displayed a delayed cell survival effect. However, the elevated physiological stress due to fibrous MPs resulted in energy transfer by compensatory regulation of metabolic processes to expedite cellular recovery. These observations highlighted the intricate and varied reaction of cell survival mechanisms in mussels to recover toxicity. This study provides critical evidence of the ecotoxicological impacts of two different MPs and emphasizes the environmental risks they pose to aquatic ecosystems. Our conclusion highlights the detrimental effects of MPs on M. galloprovincialis and the need for more stringent regulations to protect marine ecosystems.

Exposure to microplastics renders immunity of the thick-shell mussel more vulnerable to diarrhetic shellfish toxin-producing harmful algae

Despite both microplastics (MPs) and harmful algae blooms (HABs) may pose a severe threat to the immunity of marine bivalves, the toxification mechanism underlying is far from being fully understood. In addition, owing to the prevalence and sudden occurrence characteristics of MPs and HABs, respectively, bivalves with MP-exposure experience may face acute challenge of harmful algae under realistic scenarios. However, little is known about the impacts and underlying mechanisms of MP-exposure experience on the susceptibility of immunity to HABs in bivalve mollusks. Taking polystyrene MPs and diarrhetic shellfish toxin-producing Prorocentrum lima as representatives, the impacts of MP-exposure on immunity vulnerability to HABs were investigated in the thick-shell mussel, Mytilus coruscus. Our results revealed evident immunotoxicity of MPs and P. lima to the mussel, as evidenced by significantly impaired total count, phagocytic activity, and cell viability of haemocytes, which may result from the induction of oxidative stress, aggravation of haemocyte apoptosis, and shortage in cellular energy supply. Moreover, marked disruptions of immunity, antioxidant system, apoptosis regulation, and metabolism upon MPs and P. lima exposure were illustrated by gene expression and comparative metabolomic analyses. Furthermore, the mussels that experienced MP-exposure were shown to be more vulnerable to P. lima, indicated by greater degree of deleterious effects on abovementioned parameters detected. In general, our findings emphasize the threat of MPs and HABs to bivalve species, which deserves close attention and more investigation.

Microplastics dysregulate innate immunity in the SARS-CoV-2 infected lung

Introduction

Global microplastic (MP) pollution is now well recognized, with humans and animals consuming and inhaling MPs on a daily basis, with a growing body of concern surrounding the potential impacts on human health.

Methods

Using a mouse model of mild COVID-19, we describe herein the effects of azide-free 1 μm polystyrene MP beads, co-delivered into lungs with a SARS-CoV-2 omicron BA.5 inoculum. The effect of MPs on the host response to SARS-CoV-2 infection was analysed using histopathology and RNA-Seq at 2 and 6 days post-infection (dpi).

Results

Although infection reduced clearance of MPs from the lung, virus titres and viral RNA levels were not significantly affected by MPs, and overt MP-associated clinical or histopathological changes were not observed. However, RNA-Seq of infected lungs revealed that MP exposure suppressed innate immune responses at 2 dpi and increased pro-inflammatory signatures at 6 dpi. The cytokine profile at 6 dpi showed a significant correlation with the 'cytokine release syndrome' signature observed in some COVID-19 patients.

Discussion

The findings are consistent with the recent finding that MPs can inhibit phagocytosis of apoptotic cells via binding of Tim4. They also add to a growing body of literature suggesting that MPs can dysregulate inflammatory processes in specific disease settings.

Context-dependent antioxidant defense system (ADS)-based stress memory in response to recurrent environmental challenges in congeneric invasive species

Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities, imposing pressures on marine species. To withstand recurring environmental challenges, marine organisms, especially benthic species lacking behavioral choices to select optimal habitats, have to utilize well-established strategies such as the antioxidant defense system (ADS) to ensure their survival. Therefore, understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges. Here we conducted a comparative analysis of the physiological and transcriptional responses based on the ADS during two rounds of 'hypersalinity-recovery' challenges in two model congeneric invasive ascidians, Ciona robusta and C. savignyi. Our results demonstrated that C. savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level, while C. robusta demonstrated heightened responses at the transcriptional level. We observed distinct transcriptional responses, particularly in the utilization of two superoxide dismutase (SOD) isoforms. Both Ciona species developed physiological stress memory with elevated total SOD (T-SOD) and glutathione (GSH) responses, while only C. robusta demonstrated transcriptional stress memory. The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species. These findings support the 'context-dependent stress memory hypothesis', emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges. Our results enhance our understanding of the mechanisms of environmental challenge management in marine species, particularly those related to the ADS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-024-00228-y.

Toxic effects of microplastics and nitrite exposure on intestinal histology, digestion, immunity, and microbial community of shrimp Litopenaeus vannamei

Nitrite and microplastics (MPs) are environmental pollutants that threaten intestinal integrity and affect immune function of shrimp. In this study, the shrimp Litopenaeus vannamei were exposed to the individual and combined stress of nitrite and microplastics for 14 days, and the changes of intestinal histology and physiological functions were investigated. After single and combined stress, affectations occurred in intestinal tissue; the antioxidant enzyme activities (MDA, H2O2, CAT increased) and gene expression levels (CAT, SOD, GPx, HSP70 up-regulated) changed. The expression levels of detoxification genes (CYP450, UGT down-regulated, GST up-regulated), apoptosis genes (CASP-3 up-regulated) and endoplasmic reticulum stress genes (Bip, GRP94 down-regulated) changed. Furthermore, the stress also increased intestinal microbial diversity, causing bacterial composition variation, especially beneficial bacteria and pathogenic bacteria. These results suggested that nitrite and microplastics stress had adverse effects on the intestinal health of L. vannamei by affecting intestinal tissue morphology, immune response and microbial community.

Immunotoxicity of microplastics and polychlorinated biphenyls alone or in combination to Crassostrea gigas

Microplastics (MPs) and polychlorinated biphenyls (PCBs) are pervasive pollutants in the marine environment, exerting adverse effects on marine organisms. While it is suggested that their exposure may compromise the immune responses of marine organisms, the cumulative immunotoxic effects remain uncertain. Additionally, the intricate mechanisms underlying the immunotoxicity of PCBs and MPs in marine organisms are not yet fully comprehended. To illuminate their combined biological impacts, Crassostrea gigas were exposed to 50 μg/L MPs (30-μm porous) alone, as well as 10 or 100 ng/L PCBs individually or in combination with 50 μg/L of MPs for 28 days. Our data demonstrated that oysters treated with the pollutants examined led to decreased total haemocyte count, inhibited phagocytosis of haemocytes, enhanced the intracellular contents of reactive oxygen species, lipid peroxidation and DNA damage, reduced lysozyme concentration and activity, gave rise to superoxide dismutase. Catalaseand glutathione S-transferaseactivity. The expression of three immune-related genes (NF-κB, TNF-α, TLR-6) was drastically suppressed by the PCBs and MPs treatment, while the apoptosis pathway-related genes (BAX and Caspase-3) showed a significant increase. In addition, compared to oysters treated with a single type of pollutant, coexposure to MPs and PCBs exerted more severe adverse impacts on all the parameters investigated, indicating a significant synergistic effect. Therefore, the risk of MPs and PCBs chemicals on marine organisms should be paid more attention.

Occurrence, transport, and toxicity of microplastics in tropical food chains: perspectives view and way forward

Microplastics, which have a diameter of less than 5 mm, are becoming an increasingly prevalent contaminant in terrestrial and aquatic ecosystems due to the dramatic increase in plastic production to 390.7 million tonnes in 2021. Among all the plastics produced since 1950, nearly 80% ended up in the environment or landfills and eventually reached the oceans. Currently, 82-358 trillion plastic particles, equivalent to 1.1-4.9 million tonnes by weight, are floating on the ocean's surface. The interactions between microorganisms and microplastics have led to the transportation of other associated pollutants to higher trophic levels of the food chain, where microplastics eventually reach plants, animals, and top predators. This review paper focuses on the interactions and origins of microplastics in diverse environmental compartments that involve terrestrial and aquatic food chains. The present review study also critically discusses the toxicity potential of microplastics in the food chain. This systematic review critically identified 206 publications from 2010 to 2022, specifically reported on microplastic transport and ecotoxicological impact in aquatic and terrestrial food chains. Based on the ScienceDirect database, the total number of studies with "microplastic" as the keyword in their title increased from 75 to 4813 between 2010 and 2022. Furthermore, various contaminants are discussed, including how microplastics act as a vector to reach organisms after ingestion. This review paper would provide useful perspectives in comprehending the possible effects of microplastics and associated contaminants from primary producers to the highest trophic level (i.e. human health).

Physiological and histopathological effects of polystyrene nanoparticles on the filter-feeding fish Hypophthalmichthys molitrix

Excessive use of plastics in daily life is causing plastic pollution in aquatic environment and threatening the aquatic life. Therefore, research on the plastic pollution in aquatic environment is crucial to understand its impact and develop effective solution for safeguarding aquatic life and ecosystem. The current study investigated the effects of water borne polystyrene nanoparticles (PS-NPs) on hemato-immunological indices, serum metabolic enzymes, gills, and liver antioxidant parameters, plasma cortisol level and histopathological changes in liver and gill tissues of the widely distributed fish Hypophthalmichthys molitrix. The fingerlings of H. molitrix were exposed to different concentrations (T1-0.5, T2-1.0, and T3-2.0 mg/L) of PS-NPs respectively for 15 days consecutively. Our results indicated the dose dependent negative effects of PS-NPs on the physiology and histopathology of H. molitrix. Immuno-hematological indices showed significant increase in WBCs count, phagocytic activity, and lysozyme activity, while decreased RBC count, Hct%, Hb level, total proteins, IgM, and respiratory burst activity were observed. The levels of antioxidant enzymes like SOD, CAT and POD showed the decreasing trends while metabolic enzymes (AST, ALT, ALP and LDH), LPO, ROS activities and relative expressions of SOD1, CAT, HIF1-α and HSP-70 genes increased with increased concentrations of PS-NPs. Moreover, blood glucose and cortisol levels also showed significant increasing trends with dose dependent manner. Histopathological examination indicated moderate to severe changes in the gills and liver tissues of the group treated with 2.0 mg/L of PS-NPs. Overall, the results showed the deleterious effects of PS-NPs on physiology, immunity, metabolism, and gene expressions of H. molitrix. It is concluded that particulate plastic pollution has deleterious effects on filter feeding fish, which might affect human health through food chain and particulate chemical toxicity.

Responses of Mytilus galloprovincialis in a Multi-Stressor Scenario: Effects of an Invasive Seaweed Exudate and Microplastic Pollution under Ocean Warming

Microplastic pollution, global warming, and invasive species are known threats to marine biota, but the impact of their simultaneous exposure is still not well understood. This study investigated whether the toxic effects posed by the invasive red seaweed Asparagopsis armata exudate (2%) to the mussel Mytilus galloprovincialis are amplified by a 96 h exposure to increased temperature (24 °C) and polyethylene microplastics (PE-MPs, 1 mg/L). Biochemical (neurotoxicity, energy metabolism, oxidative stress, and damage) and physiological (byssal thread production) responses were evaluated. The number of produced byssus greatly decreased under concomitant exposure to all stressors. The antioxidant defences were depleted in the gills of mussels exposed to temperature rises and PE-MPs, regardless of exudate exposure, preventing oxidative damage. Moreover, the heat shock protein content tended to decrease in all treatments relative to the control. The increased total glutathione in the mussels' digestive gland exposed to 24 °C, exudate, and PE-MPs avoided oxidative damage. Neurotoxicity was observed in the same treatment. In contrast, the energy metabolism remained unaltered. In conclusion, depending on the endpoint, simultaneous exposure to A. armata exudate, PE-MPs, and warming does not necessarily mean an amplification of their single effects. Studies focusing on the impact of multiple stressors are imperative to better understand the underlying mechanisms of this chronic exposure.

Effect of Polystyrene Microplastics on the Antioxidant System and Immune Response in GIFT (Oreochromis niloticus)

Recent studies have revealed a significant presence of microplastics (MPs) in freshwater ecosystems, raising concerns about their potential negative impacts on the growth and development of freshwater organisms. The present study was conducted to examine the effects of chronic sub-lethal doses of polystyrene microsphere MPs on the oxidative status (ROS, SOD) and the immune response (IL-1ß, TNF-α) of genetically improved farmed tilapia (a kind of tilapia hereafter referred to as GIFT). GIFT juveniles (5.1 ± 0.2 g) were exposed to different concentrations of substances. The experimental groups were as follows: group A (control, no exposure), group B (exposed to a concentration of 75 nm), group C (exposed to a concentration of 7.5 μm), group D (exposed to a concentration of 750 μm), group E (exposed to a combination of 75 nm, 7.5 μm, and 750 μm), and group F (exposed to a combination of 75 nm and Chlorella). The ROS contents in the brain and gills were significantly decreased in group F, while a significant increase was observed in group D following a 14-day exposure. SOD activities in the intestine showed an elevation in group F, as did those in the brain and gills in group D, while the SOD levels in the gills generally decreased over time in groups B and F. Notably, the highest ROS and SOD were observed in the brain of group D, whereas the lowest were in the intestines at the same concentration. The activity of IL-1β in the liver was significantly up-regulated in all of the exposure groups. IL-1β was significantly up-regulated in the brain of group B and in the gills of group D. Similarly, TNF-α was significantly up-regulated in the brain of groups B/D/E, in the liver of groups B/C/D, in the intestine of group B, and in the gills of group D. Notably, the highest levels of IL-1β and TNF-α activities were recorded in the brain, while the lowest were recorded in the intestine of group D. Overall, this study revealed that GIFT's immune response and antioxidant system can be affected by MPs.

The effect of interspecific and intraspecific diversity on microplastic ingestion in two co-occurring mussel species in South Africa

Interspecific and intraspecific diversity are essential components of biodiversity with far-reaching implications for ecosystem function and service provision. Importantly, genotypic and phenotypic variation within a species can affect responses to anthropogenic pressures more than interspecific diversity. We investigated the effects of interspecific and intraspecific diversity on microplastic ingestion by two coexisting mussel species in South Africa, Mytilus galloprovincialis and Perna perna, the latter occurring as two genetic lineages. We found significantly higher microplastic abundance in M. galloprovincialis (0.54 ± 0.56 MP items g-1WW) than P. perna (0.16 ± 0.21 MP items g-1WW), but no difference between P. perna lineages. Microbeads were the predominant microplastic (76 % in P. perna, 99 % in M. galloprovincialis) and polyethylene the prevalent polymer. Interspecific differences in microplastic abundance varied across locations, suggesting diverse sources of contamination. We suggest that microplastic ingestion can be species-specific even in organisms that coexist and play similar functional roles within ecosystems.

Adverse Effects of Micro- and Nanoplastics on Humans and the Environment

The pervasive pollution caused by nano- and microplastics (N/MPLs) is a pressing concern, and was exacerbated during the COVID-19 pandemic due to the substantial release of disposable Personal Protective Equipment (PPE) into the environment [...].

Atmospheric Microplastics: Perspectives on Origin, Abundances, Ecological and Health Risks

Microplastic (MP) pollution has aroused a tremendous amount of public and scientific interest worldwide. MPs are found widely ranging from terrestrial to aquatic ecosystems primarily due to the over-exploitation of plastic products and unscientific disposal of plastic waste. There is a large availability of scientific literature on MP pollution in the terrestrial and aquatic ecosystems, especially the marine environments; however, only recently has greater scientific attention been focused on the presence of MPs in the air and its retrospective health implications. Besides, atmospheric transport has been reported to be an important pathway of transport of MPs to the pristine regions of the world. From a health perspective, existing studies suggest that airborne MPs are priority pollutant vectors, that may penetrate deep into the body through inhalation leading to adverse health impacts such as neurotoxicity, cancer, respiratory problems, cytotoxicity, and many more. However, their effects on indoor and outdoor air quality, and on human health are not yet clearly understood due to the lack of enough research studies on that and the non-availability of established scientific protocols for their characterization. This scientific review entails important information concerning the abundance of atmospheric MPs worldwide within the existing literature. A thorough comparison of existing sampling and analytical protocols has been presented. Besides, this review has unveiled the areas of scientific concern especially air quality monitoring which requires immediate attention, with the information gaps to be filled have been addressed.

The impact of microplastics on bivalve mollusks: A bibliometric and scientific review

Bivalves are important members of the ecosystem and their populations are declining globally, making them a concern for their role in ecosystem services and the fishing industry. Bivalves are excellent bioindicators of MPs pollution due to their widespread distribution, filtering capabilities, and close association with human health. Microplastics (MPs) have direct and indirect impacts on bivalves, affecting their physiology, habitat structure, food sources, and persistence of organic pollutants. This review provides an extensive overview of the impact of MPs on bivalves, covering various aspects such as their economic significance, ecological roles, and importance in biomonitoring environmental quality. The article presents the current state of knowledge on the sources and pathways of MPs in aquatic environments and their effects on bivalves. The mechanisms underlying the effects of MPs on bivalves, including ingestion, filtration activity, feeding inhibition, accumulation, bioaccumulation, and reproduction, are also discussed. Additionally, a bibliometric analysis of research on MPs in bivalves is presented, highlighting the number of papers, geographical distribution, and keyword clusters relating to MPs. Finally, the review emphasizes the importance of ongoing research and the development of mitigation strategies to reduce the negative effects of MPs pollution on bivalves and their habitats in oceans and coastal waters.

Toxic effects of sub-acute microplastic (polyamide) exposure on the accumulation, hematological, and antioxidant responses in crucian carp, Carassius carassius

The purpose of this study is to investigate the impact of microplastics (MPs) on fish and to confirm the toxic effects of MPs on fish, as well as to clarify the standard indicators. MPs are present in a large amount in the aquatic environment and can have various adverse effects on aquatic animals. Crucian carp, Carassius carassius (mean weight, 23.7 ± 1.6 g; mean length, 13.9 ± 1.4 cm), were exposed to PA (Polyamide) concentrations of 0, 4, 8, 16, 32 and 64 mg/L for 2 weeks. The PA accumulation profile in C. carassius decreased from the intestine to the gill to the liver. Hematological parameters such as red blood cell (RBC) counts, hemoglobin (Hb), and hematocrit (Ht) notably decreased at high levels of PA exposure. Plasma components such as calcium, magnesium, glucose, cholesterol, total protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) were significantly altered by PA exposure. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and glutathione (GSH) of liver, gill and intestine significantly increased following PA exposure. The results of this study suggest that MP exposure affects the hematological physiology and antioxidant responses in C. carassius as well as accumulation in specific tissues.

Study of the ageing and the sorption of polyaromatic hydrocarbons as influencing factors on the effects of microplastics on blue mussel

The mussels are species with high socio-economic weights and are often used as bioindicators of biological and chemical contamination. In the field and aquaculture, they can intake microplastics during filter-feeding, and the microplastics can have a negative impact on their health, even at low concentrations. The effects of microplastics have yet to be fully examined on the blue mussel (Mytilus edulis), considering the factors of ageing and sorption of some polyaromatic hydrocarbons (PAHs), ubiquitous environmental contaminants. In this work, 5 different exposure conditions were studied: pristine microplastics, microplastics aged for 1000 days under UV radiation, microplastics sorbing PAHs, as well as microplastics both aged and sorbing PAHs, in parallel to controls. The microplastic changes after ageing were studied with spectroscopic and chromatographic methods. Then, 8-day laboratory exposures of mussels at 10 µg/L of microplastics were performed. The oxidative stress, as well as neurotoxic and immunological responses of M. edulis, were measured using a battery of biomarkers (catalase/CAT, superoxide dismutase/SOD, glutathione S-transferases/GST, acetylcholinesterase/AChE) in 3 different organs (digestive gland, gills and mantle), and acid phosphatase in hemolymph. Then, a study of lipid impairments on the digestive gland was performed through the use of lipidomic tools. No significant difference of oxidative stress activity was observed for all the tissues of mussels exposed to pristine microplastics at 10 µg/L, compared to controls. The ageing and the PAH soption onto microplastics were influencing factors of the oxydative stress in mussels with increased CAT activities in the digestive glands and decreased SOD activities in the mantles. The neurotoxicity was highlighted by higher AChE activities measured in the mantle of mussels exposed to all the microplastic treatments, compared to controls. Concerning lipidomics, no compound was determined as a biomarker of microplastic exposure. The study demonstrated a low toxicity of microplastics at environmental relevant concentration with a 8-day exposure and using the chosen biomarkers. However, some microplastic changes seemed to lead to specific effects on mussels.

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.

Impact of polyethylene microplastics on the clam Ruditapes decussatus (Mollusca: Bivalvia): examination of filtration rate, growth, and immunomodulation

The present study was conducted to assess, for the first time, the effects of a 14 days experimental exposure to polyethylene (PE) based MPs (40-48 µm) on the clam Ruditapes decussatus. Clams were exposed to three different concentrations of MPs in controlled laboratory conditions: 10 µg/L (low), 100 µg/L (medium), and 1000 µg/L (high). The effects of MPs were assessed using a multi-marker approach, including the filtration rate, growth, and the integrity of immune cells (such as haemocyte numbers, viability, and lysosomal membrane destabilization). The results revealed that as the concentration of PE-MPs increased, the filtration rate decreased, indicating that PE-MPs hindered the clams' ability to filter water. Furthermore, there was a noticeable decrease in the overall weight of the clams, particularly in the group exposed to 1000 µg/L. This decrease could be attributed to the impairment of their nutrient filtration function. In terms of immune system biomarkers, exposure to PE-MPs led to immune system disruption, characterized by a significant increase in the number of haemocytic cells, especially in the group exposed to the high concentration. Additionally, there was a notable reduction in the viability of haemocytes, resulting in the destabilization of their lysosomal membranes, particularly in the groups exposed to medium and high PE-MPs concentrations. The findings of this study indicate that the sensitivity of hemolymph parameter changes and filtration rate in R. decussatus exposed to PE-MPs (100 and 1000 µg/L), surpasses that of growth performance and can serve as reliable indicators to assess habitat conditions and contaminant levels.

The combined effects of polyethylene microplastics and benzoanthracene on Manila clam Ruditapes philippinarum

Microplastic (MP) toxicity has recently been explored in various marine species. Along with the toxicity of plastics polymer itself, additional substances or pollutants that are absorbed onto it may also be harmful. In the present study, we investigated the combined impacts of polyethylene microplastics (PE MPs) and an organic pollutant (Benzo(a)anthracene, BaA) on Manila clam Ruditapes philippinarum during a one-week exposure. Two PE MPs concentrations (26 μg L^-1 and 260 μg L^-1) and one BaA concentration (3 μg L^-1) were tested. The clams were exposed to BaA and PE MPs either alone or in combination. BaA and PE MPs were incubated before the combined exposure. The biological effects of PE MPs and BaA on the clams were evaluated by considering several assays such as feeding rate, anti-oxidant enzyme activities, and the expression levels of stress-related genes. The feeding rate significantly decreased in individual PE MPs and individual BaA groups while it remained unchanged in combined groups. Superoxide dismutase (SOD) was the most affected among the biochemical parameters. Malondialdehyde (MDA), and glutathione peroxidase (GPx) activities were slightly affected, whereas no changes were observed in glutathione s-transferase (GST) activities. CYP1A1, CYP3A4, and HSP70 gene expressions displayed slightly significant changes. Considering all stressor groups, high PE MPs exposure (260 μg L^-1 PE MPs) more effectively altered the biological parameters in the clams compared to individual low PE MPs and BaA exposure, and their combination. The results also indicated the negligible vector role of PE MPs to transport BaA into the clam tissues.

Functional Trait-Based Evidence of Microplastic Effects on Aquatic Species

Microplastics represent an ever-increasing threat to aquatic organisms. We merged data from two global scale meta-analyses investigating the effect of microplastics on benthic organisms' and fishes' functional traits. Results were compared, allowing differences related to vertebrate and invertebrate habitat, life stage, trophic level, and experimental design to be explored. Functional traits of aquatic organisms were negatively affected. Metabolism, growth, and reproduction of benthic organisms were impacted, and fish behaviour was significantly affected. Responses differed by trophic level, suggesting negative effects on trophic interactions and energy transfer through the trophic web. The experimental design was found to have the most significant impact on results. As microplastics impact an organism's performance, this causes indirect repercussions further up the ecological hierarchy on the ecosystem's stability and functioning, and its associated goods and services are at risk. Standardized methods to generate salient targets and indicators are urgently needed to better inform policy makers and guide mitigation plans.

Microplastics in coastal and oceanic surface waters and their role as carriers of pollutants of emerging concern in marine organisms

Microplastics (Mps) pose a significant environmental challenge with global implications. To examine the effect of Mps on coastal and oceanic surface waters, as well as in marine organisms, 167 original research papers published between January 2013 and September 2022 were analyzed. The study revealed an unequal distribution of research efforts across the world. Fragments and fibers were the most frequently detected particles in ocean surface waters and marine biota, which mainly consisted of colored and transparent microparticles. Sampling of Mps was primarily done using collecting nets with a mesh size of 330 μm. Most articles used a stereomicroscope and Fourier-Transform Infrared spectroscopy for identification and composition determination, respectively. Polyethylene and polypropylene were the most frequent polymers found, both in coastal waters and in marine organisms. The major impact observed on marine organisms was a reduction in growth rate, an increase in mortality, and reduced food consumption. The hydrophobic nature of plastics encourages the formation of biofilms called the "plastisphere," which can carry pollutants that are often toxic and can enter the food chain. To better define management measures, it is necessary to standardize investigations that assess Mp pollution, considering not only the geomorphological and oceanographic features of each region but also the urban and industrial occupation of the studied marine environments.

Dietary Exposure to Particles of Polytetrafluoroethylene (PTFE) and Polymethylmethacrylate (PMMA) Induces Different Responses in Periwinkles Littorina brevicula

The marine and ocean water pollution with different-sized plastic waste poses a real threat to the lives of the next generations. Plastic, including microplastics, is found in all types of water bodies and in the organisms that live in them. However, given the chemical diversity of plastic particles, data on their toxicity are currently incomplete. Moreover, it is clear that different organisms, depending on their habitat and feeding habits, are at different risks from plastic particles. Therefore, we performed a series of experiments on feeding the gastropod scraping mollusk Littorina brevicula with two types of polymeric particles-polymethylmethacrylate (PMMA) and polytetrafluoroethylene (PTFE)-using a special feeding design. In the PMMA-exposed group, changes in gastrointestinal biochemical parameters such as increases in malondialdehyde (MDA) and protein carbonyls (PC) were detected, indicating the initiation of oxidative stress. Similarly, a comet assay showed an almost twofold increase in DNA damage in digestive gland cells compared to the control group. In mollusks fed with PTFE-containing food, no similar changes were recorded.

Health Effects of Microplastic Exposures: Current Issues and Perspectives in South Korea

Microplastics are environmental pollutants that prevail in the oceans, remote islands, and polar regions. Exposure to microplastics presents a major emerging threat to the ecosystems due to their potential adverse effects. Herein, we reviewed the literature to provide an up-to-date synopsis of the current understanding of the sources, compositions, and adverse effects of microplastics in humans and the environment. Most studies on microplastics have focused on developing standardized methods for monitoring the occurrence, distribution, and movement of microplastics in the environment, as well as developing microplastic substitutes; however, although humans are exposed to microplastics via various routes, research on the adverse effects of microplastics in humans remains limited. Little is known about the impact of microplastics on human health and the toxic effects that may vary depending on the type, size, shape, and concentration of microplastics. Therefore, more research is needed to understand the cellular and molecular mechanisms of microplastic toxicity and related pathologies.

Microplastics as an emerging menace to environment: Insights into their uptake, prevalence, fate, and sustainable solutions

The inflated demand for plastic products has led to tremendous rise in plastic debris in different environmental matrices, thereby resulting in plastic pollution. This affects plants, animals, and even humans, as microplastics can enter the food chain and cause several health implications. Microplastics are the small plastic particles (size below 5 mm) that are largely debated nowadays owing to their environmental risk assessment. Their potential to interact with other toxic contaminants, their tendency to be ingested or taken up by living organisms and their longevity is a serious threat to our environment. However, despite wealth of recent information, still there is a gap, particularly in eco-toxicology studies, fate, prevalence and feasible solutions to cope up with the menace of microplastics pollution. This review unravels the environmental fate and behaviour of microplastics as well as their global distribution in the marine and terrestrial environment. Furthermore, we aim to contribute to the international debate on the microplastics global paradigm. We briefly suggest sustainable solutions and recommendations to achieve future research goals on microplastics. Our review reveals some of the newest biological (green algae and modified sponges) and physical (nano-particles and membrane treatment) remediation solutions to eradicate microplastics from different types of environment. This review presents a critical evaluation of the state of knowledge of micro-plastics and suggested some recommendations which can help in identifying some important key questions for future research.

Presence, variation, and potential ecological impact of microplastics in the largest shallow lake of Central Europe

The presence of microplastics (MPs) in the global ecosystem has generated a rapidly growing concern worldwide. Although their presence in the marine environment has been well-studied, much less data are available on their abundance in freshwaters. MPs alone and in combination with different chemicals has been shown to cause acute and chronic effects on algae and aquatic invertebrate and vertebrate species at different biological levels. However, the combined ecotoxicological effects of MPs with different chemicals on aquatic organisms are still understudied in many species and the reported data are often controversial. In the present study, we investigated, for the first time, the presence of MPs in Lake Balaton, which is the largest shallow lake of Central Europe and an important summer holiday destination. Moreover, we exposed neonates of the well-established ecotoxicological model organism Daphnia magna to different MPs (polystyrene [3 μm] or polyethylene [≤ 100 μm]) alone and in combination with three progestogen compounds (progesterone, drospirenone, levonorgestrel) at an environmentally relevant concentration (10 ng L^-1) for 21 days. The presence of 7 polymer types of MPs in the size range of 50-100 μm was detected in Lake Balaton. Similarly to the global trends, polypropylene and polyethylene MPs were the most common types of polymer. The calculated polymer-independent average particle number was 5.5 particles m^-3 (size range: 50 μm - 100 μm) which represents the values detected in other European lakes. Our ecotoxicological experiments confirmed that MPs and progestogens can affect D. magna at the behavioral (body size and reproduction) and biochemical (detoxification-related enzyme activity) levels. The joint effects were negligible. The presence of MPs may lead to reduced fitness in the aquatic biota in freshwaters such as Lake Balaton, however, the potential threat of MPs as vectors for progestogens may be limited.

Microplastic sink that cannot be ignored in chemosynthetic organisms

Marine microplastic (MP) pollution is a widespread concern; however, to date, MP pollution in chemoautotrophic ecosystems remains largely unknown. This study focuses on the cold seep in the South China Sea. Two dominant species, namely mussel (Gigantidas platifrons) and squat lobster (Shinkaia crosnieri), were collected for examining the MP pollution. MPs were present in both mussels and squat lobsters with abundances of 0.13 ± 0.04 and 0.17 ± 0.06 items/ind., respectively. MPs were mainly fibrous (62.5 %) and transparent (45.8 %). The main polymer type was polyester (54.2 %). About 86.5 MPs/m² were found inhabiting mussels and squat lobsters-a value comparable to those reported in benthos. This pilot report on MP pollution in cold-seep species provides key information for studies on MP pollution in chemoautotrophic ecosystems and evidence regarding a potential biological MP sink. The role of cold-seep organisms in MP retention and transport in the regional sea merits further attention.

Migration of microplastics from plastic packaging into foods and its potential threats on human health

Microplastics from food packaging material have risen in number and dispersion in the aquatic system, the terrestrial environment, and the atmosphere in recent decades. Microplastics are of particular concern due to their long-term durability in the environment, their great potential for releasing plastic monomers and additives/chemicals, and their vector-capacity for adsorbing or collecting other pollutants. Consumption of foods containing migrating monomers can lead to accumulation in the body and the build-up of monomers in the body can trigger cancer. The book chapter focuses the commercial plastic food packaging materials and describes their release mechanisms of microplastics from packaging into foods. To prevent the potential risk of microplastics migrated into food products, the factors influencing microplastic to the food products, e.g., high temperatures, ultraviolet and bacteria, have been discussed. Additionally, as many evidences shows that the microplastic components are toxic and carcinogenic, the potential threats and negative effects on human health have also been highlighted. Moreover, future trends is summarized to reduce the microplastic migration by enhancing public awareness as well as improving waste management.

Atmospheric microplastics: exposure, toxicity, and detrimental health effects

Microplastics (MPs) are micro-particulate pollutants present in all environments whose ubiquity leads humans to unavoidable exposure. Due to low density, MPs also accumulate in the atmosphere, where they are easily transported worldwide and come into direct contact with the human body by inhalation or ingestion, causing detrimental health effects. This literature review presents the sources of atmospheric MPs pollution, transport routes, physicochemical characteristics, and environmental interactions. The document also explains the implications for human health and analyzes the risk of exposure based on the potential toxicity and the concentration in the atmosphere. MPs' toxicity lies in their physical characteristics, chemical composition, environmental interactions, and degree of aging. The abundance and concentration of these microparticles are associated with nearby production sources and their displacement in the atmosphere. The above elements are presented in an integrated way to facilitate a better understanding of the associated risk. The investigation results encourage the development of future research that delves into the health implications of exposure to airborne MPs and raises awareness of the risks of current plastic pollution to promote the establishment of relevant mitigation policies and procedures.

A review of microplastic pollution in aquaculture: Sources, effects, removal strategies and prospects

As microplastic pollution has become an emerging environmental issue of global concern, microplastics in aquaculture have become a research hotspot. For environmental safety, economic efficiency and food safety considerations, a comprehensive understanding of microplastic pollution in aquaculture is necessary. This review outlines an overview of sources and effects of microplastics in aquaculture. External environmental inputs and aquaculture processes are sources of microplastics in aquaculture. Microplastics may release harmful additives and adsorb pollutants in aquaculture environment, cause deterioration of aquaculture environment, as well as cause toxicological effects, affect the behavior, growth and reproduction of aquaculture products, ultimately reducing the economic benefits of aquaculture. Microplastics entering the human body through aquaculture products also pose potential health risks at multiple levels. Microplastic pollution removal strategies used in aquaculture in various countries are also reviewed. Ecological interception and purification are considered to be effective methods. In addition, strengthening aquaculture management and improving fishing gear and packaging are also currently feasible solutions. As proactive measures, new portable microplastic monitoring system and remote sensing technology are considered to have broad application prospects. And it was encouraged to comprehensively strengthen the supervision of microplastic pollution in aquaculture through talent exchange and strengthening the construction of laws and regulations.

Microplastics in human food chains: Food becoming a threat to health safety

While versatile application of plastics has generated huge benefits in our life, the 'plastic end-of-life' comes with downsides of emerging concern is plastic particles within all parts of environments. Plastics are highly resistant to degradation and sustain in the environment for a prolonged period resulting in easy access of microplastics into human food chain. Microplastic exposure to humans is caused by foods of both animal and plant origin, food additives, drinks, and plastic food packaging. Living organisms can accumulate microplastics in cells and tissues which results in threats of chronic biological effects and potential health hazards for humans including body gastrointestinal disorders, immunity, respiratory problem, cancer, infertility, and alteration in chromosomes. Because of the threat of microplastics on human health, it is essential to ensure food safety as well as control plastic use with strict regulation of proper management. This study aims to enlighten future research into the core component of microplastics, their exposure to human food, prevention to human food chain, and biological reactions in human body. Finally, it is recommended to consider the presence of microplastics in different foods, as most of the existing research mainly focused on sea foods. And it is important to study the mechanism of toxicity with pathways in the human body based on the different types, shapes, and sizes of plastic particles.

Distinguish the toxic differentiations between acute exposure of micro- and nano-plastics on bivalves: An integrated study based on transcriptomic sequencing

Plastic pollution represents one of the most severe marine environmental issues today. In the present study, mussel Mytilus coruscus, was selected as the model organism to probe the toxic effects of acute exposure to different sizes of plastic particles using integrated transcriptomic techniques and histological and biochemical analysis. Nanoplastics (NPs) were efficiently ingested by mussels, thereby inducing a severe inflammatory response. Although no distinct aggregation of microplastics (MPs) was observed, a slight inflammatory response has still occurred. Biochemical analysis revealed a significant up-regulation of biomarkers after exposure to plastic particles. Further, NPs caused more ROS production and higher T-AOC level than MPs. Transcriptomic sequencing was performed, and these differentially expressed genes after MNPs exposure were mostly enriched in pathways involved in stress and immune response. Notably, a contrast expression, substantial upregulation in MPs treatment and downregulation in NPs treatment of specific genes include in these pathways were revealed. Collectively, these results indicated that acute exposure to NPs is more toxic than MPs. Additionally, MPs exposure perhaps caused the impairment of olfactory function and neurotoxicity to mussels. These data provided some new clues for the elucidating of ecotoxicological mechanisms underlying plastic particles exposure.

Tire microplastics exposure in soil induces changes in expression profile of immune-related genes in terrestrial crustacean Porcellio scaber

Tire particles pose a potential threat to terrestrial organisms because they are deposited in large quantities in the soil by tire wear abrasion, and moreover their chemical complexity poses an additional risk. Microplastics can affect several physiological processes in organisms, including those related to immunity. Therefore, we investigated the expression profile of selected immune-related genes (MnSod, Manganese Superoxide dismutase; Cat, Catalase; CypG, Cyclophilin G; Nos, Nitric oxide synthase; Ppae2a, Prophenoloxidase-activating enzyme 2a; Dscam, Down syndrome cell adhesion molecule; Myd88, Myeloid-differentiation factor 88; Toll4, Toll-like receptor 4; Mas-like, Masquerade-like protein) in haemocytes and the digestive gland hepatopancreas of terrestrial crustacean Porcellio scaber after two different time exposures (4 and 14 days) to tire particles in soil. Our results reveal for the first time the response of P. scaber after microplastic exposure at the transcriptome level. We observed time- and tissue-dependent changes in the expression of the analysed genes, with more pronounced alterations in haemocytes after 14 days of exposure. Some minor changes were also observed in hepatopancreas after 4 days. Changes in the expression profile of the analysed genes are a direct indication of a modulated immune status of the test organism, which, however, does not represent an adverse effect on the test organism under the given conditions. Nevertheless, the question remains whether the observed change in immune status affects the immunocompetence of the test organism.

Are Ingested or Inhaled Microplastics Involved in Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) has emerged as the predominant cause of chronic liver injury; however, the mechanisms underlying its progression have not been fully elucidated. Pathophysiological studies have stated that NAFLD is significantly influenced by dietary and environmental factors that could participate in the development of NAFLD through different mechanisms. Currently, "plastic pollution" is one of the most challenging environmental problems worldwide since several plastics have potential toxic or endocrine disputing properties. Specifically, the intake of microplastics (MPs) and nanoplastics (NPs) in water or diet and/or the inhalation from suspended particles is well established, and these particles have been found in human samples. Laboratory animals exposed to MPs develop inflammation, immunological responses, endocrine disruptions, and alterations in lipid and energy metabolism, among other disorders. MPs additives also demonstrated adverse reactions. There is evidence that MPs and their additives are potential "obesogens" and could participate in NAFLD pathogenesis by modifying gut microbiota composition or even worsen liver fibrosis. Although human exposure to MPs seems clear, their relationship with NAFLD requires further study, since its prevention could be a possible personalized therapeutic strategy. Adequate mitigation strategies worldwide, reducing environmental pollution and human exposure levels of MPs, could reduce the risk of NAFLD.

The legacy effect of microplastics on aquatic animals in the depuration phase: Kinetic characteristics and recovery potential

The prevalence of microplastics (MPs) in global aquatic environments has received considerable attention. Currently, concerns have been raised regarding reports that the adverse effect of MPs on aquatic animals in the exposure phase may not be (completely) reversed in the depuration phase. In order to provide insights into the legacy effect of MPs from the depuration phase, this study evaluated the kinetic characteristics and recovery potential of aquatic animals after the exposure to MPs. More specifically, a total of 68 depuration kinetic curves were highly fitted to estimate the retention time of MPs. It was shown that the retention time ranged from 1.26 to 3.01 days, corresponding to the egestion of 90 % to 99 % of ingested MPs. The retention time decreased with the increased retention rate. Furthermore, variables potentially affecting the retention time were ranked by the decision tree-based eXtreme Gradient Boosting (XGBoost) algorithm, suggesting that the particle size and tested species were of great importance for explaining the difference in retention time of MPs. Moreover, a biomarker profile was recompiled to determine the toxic changes. Results indicated that the MPs-induced toxicity significantly reduced in the depuration phase, evidenced by the recovery of energy reserves and metabolism, hepatotoxicity, immunotoxicity, hematological parameters, neurotoxicity and oxidative stress. However, the continuous detoxification and remarkable genotoxicity implied that the toxicity was not completely alleviated. In addition, the current knowledge gaps are also highlighted, with recommendations proposed for future research.

Evaluation of potential toxicity of polyethylene microplastics on human derived cell lines

Microplastics bare of major concern for environmental conservation and animal welfare in recent years as its use has increased tremendously. Polyethylene microplastics (PE-MPs) are the most common microplastics and could get exposed to humans via different routes with oral>inhalation>dermal. Internalization of MPs through epithelial tissue could expose MPs to various cells such as dendritic cells, macrophages/monocytes, and/or T cells. In this study, we aimed at identifying the effects of two different sized (30.5 ± 10.5 and 6.2 ± 2.0 μm) PE-MPs on different human cell lines representing different tissues or cells that get exposed to MPs directly or indirectly. Six cell lines were cultured with different concentrations of PE-MPs and cell viability, intracellular reactive oxygen species (ROS), nitric oxide (NO), and cytokines were measured. PE-MPs did not substantially lower the cell viability of cells however highest concentration (1000 μg/mL) of both sized MPs slightly reduced cell viability in intestinal epithelial Caco-2 and lung epithelial A549 cells. Both sized PE-MPs induced higher NO in all the cell lines and upregulation of ROS generation was demonstrated at THP-1, Jurkat, and U937 immune cell lines. A pro-inflammatory cytokine response was seen in HaCaT keratinocyte cells when cultured with PE-MPs whereas the opposite effect was observed in THP-1 and U937 cells except with THP-1 cells cultured with larger-sized MPs. We found that the PE-MPs do not have the same effects on all kinds of cells and tissues exposed and the immune modulation is not necessarily inflammatory. Thus, this study gives insight into why more detailed studies focused on exposure routes and organ-specific effects of different MPs need to be carried out.