Effects of plastic particles on aquatic invertebrates and fish - A review

Environmental toxicology of microplastic particles on fish: A review

The increase in plastic debris and its environmental impact has been a major concern for scientists. Physical destruction, chemical reactions, and microbial activity can degrade plastic waste into particles smaller than 5 mm, known as microplastics (MPs). MPs may eventually enter aquatic ecosystems through surface runoff. The accumulation of MPs in aquatic environments poses a potential threat to finfish, shellfish, and the ecological balance. This study investigated the effect of MP exposure on freshwater and marine fish. MPs could cause significant harm to fish, including physical damage, death, inflammation, oxidative stress, disruption of cell signalling and cellular biochemical processes, immune system suppression, genetic damage, and reduction in fish growth and reproduction rates. The activation of the detoxification system of fish exposed to MPs may be associated with the toxicity of MPs and chemical additives to plastic polymers. Furthermore, MPs can enhance the bioavailability of other xenobiotics, allowing these harmful substances to more easily enter and accumulate in fish. Accumulation of MPs and associated chemicals in fish can have adverse effects on the fish and humans who consume them, with these toxic substances magnifying as they move up the food chain. Changes in migration and reproduction patterns and disruptions in predator-prey relationships in fish exposed to MPs can significantly affect ecological dynamics. These interconnected changes can lead to cascading effects throughout aquatic ecosystems. Thus, implementing solutions like reducing plastic production, enhancing recycling efforts, using biodegradable materials, and improving waste management is essential to minimize plastic waste and its environmental impact.

Unlocking the combined impact of microplastics and emerging contaminants on fish: A review and meta-analysis

Microplastics (MPs) possess unique adsorptive properties that render their surfaces prone to absorbing other contaminants. When interacting with these emerging contaminants, MPs may have unpredictable negative impacts on fish. Prior studies have primarily concentrated on the impact of single contaminants, while investigations into combined pollution have not received adequate attention. Therefore, research on combined pollution holds greater practical significance. The physiological indicators of fish affected by emerging contaminants and the mechanisms behind these effects are not yet fully clear. To address this issue, a meta-analysis was performed to evaluate the impact of combined pollution of MPs-containing emerging contaminants on various aspects of fish health, encompassing behavior, consumption, development, and reproduction, along with the assessment of oxidative stress and neurotoxicity of fish. The results of the meta-analysis indicated that combined pollution adversely impacted fish reproduction, development, oxidative stress, and neurotoxicity. Importantly, significant differences were observed between fish species regarding their susceptibility to function and oxidative stress. Further investigation into the mechanisms of the impact of combined pollution on fish revealed that the magnitude of this impact is closely associated with the characteristics of the MPs themselves. MPs with higher adsorption capacities tend to lead to more severe consequences, while the impact of MPs with lower adsorption capacities relies more on their toxicity. Nevertheless, a close correlation between the duration of exposure to combined pollution and the level of oxidative stress in fish was not identified. Through a systematic analysis of existing studies, this review not only explored the cumulative effects of combined pollution on fish but also highlighted the intricate nature of such pollution within aquatic ecosystems. It contributes to the growing body of knowledge on the subject and emphasizes the need for further research to unravel the complexities associated with the combined impact of MPs-containing emerging contaminants on aquatic life.

Health check-up of a freshwater bivalve exposed to lithium

Lithium (Li) has become essential for energy and digital transitions, especially as a component of rechargeable batteries. Its growing uses worldwide lead to increasing anthropogenic releases of Li into the environment, which is making Li as an emerging contaminant. It is thus critical to evaluate the ecotoxicological impact of Li, which has been poorly studied unlike its human toxicology. The objectives of this work were to assess the potential adverse effects of Li on aquatic ecosystems. Bioaccumulation and potential sublethal effects (at individual and cellular levels) of Li have been investigated in the widespread and ecologically relevant freshwater bivalve Dreissena polymorpha. To tackle these issues, mussels were exposed to several spiking of 40, 100 and 250 μg Li L-1 for 28 days to reproduce anthropogenic contamination scenario. Results demonstrated that bivalves significantly accumulated Li in a dose-dependent manner, from 2 to 10 μg g-1 dry weight (bioaccumulation factor, BAF ≈ 19 L kg-1). Bioaccumulation of Li reached a steady-state from seven days of exposure and BAF values were constant regardless the exposure concentration indicating a tight regulation of Li body burden. Lithium exposure leads to increased energy demand associated with a higher lactate dehydrogenase activity and the decrease of protein concentrations. The observed weight gain, increased cellular metabolism, decreased apoptosis, induction of antioxidant defenses and cation content modification in D. polymorpha were also reported in previous studies on humans. The observed effects intensified with exposure concentration and duration, which implies an increased risk for aquatic organisms exposed to Li chronic contamination. Overall, the present study provides new knowledge concerning the impact of Li on non-targeted species, which have implications for the environmental risk assessment of Li in freshwater ecosystems. It also open new perspectives for the understanding of Li toxicokinetics and toxicodynamics on freshwater organisms.

First evidence of microplastic ingestion by the European grayling, Thymallus thymallus, in sub-Arctic regions: Insights on plastic pollution and preliminary risk assessment in the Teno River (Finland)

Marine litter pollution affects even remote environments such as the Arctic regions and their biodiversity. However, due to the inaccessibility and difficulty of regular observations in these environments, further studies are needed to fill the knowledge gaps. In this regard, the present investigation provides new insights on microplastic contamination levels in Arctic riverfish by analyzing, for the first time, plastic ingestion by the European grayling Thymallus thymallus from the Teno River (northern Finland), an important fishery resource and vulnerable species; and performing a preliminary ecological risk assessment of microplastics in the Finnish river using the European grayling. Plastic abundance and characterization were explored, and microplastic concentrations and polymer hazardous were also used to assess human and environmental risk. The higher frequency of occurrence (%O = 50) observed in the riverfish and the characterization of the extracted plastic confirm that riverine environment is one of the main pathways for microplastic pollution in Arctic regions and suggest the influence of the surrounding environment and human activities, mainly recreational fishing. Finally, the preliminary risk assessment highlights an ecological threat to the Teno River. This research represents a first step for the study of a commercially important Arctic freshwater species as well as in remote Arctic rivers and support identification of priorities, the application of management strategies and further environmental and human-health risk assessments according to the recommendation of Arctic Monitoring Plan and Monitoring Guidelines.

Gut microbiota perturbation and subsequent oxidative stress in gut and kidney tissues of zebrafish after individual and combined exposure to inorganic arsenic and fluoride

Chronic exposure to inorganic arsenic (iAs) and fluoride (F) affect gut health and potentially damage organs. The present study investigates the interplay between gut bacteria and oxidative stress (measured by MDA level, GSH level, catalase activity, Nrf2 translocation and expression) in zebrafish exposed to F (NaF 15 ppm) and As (As2O3 50 ppb) alone or in combination. Combined exposure to As and F reduced gut bacterial alteration and imposed less oxidative stress compared to F- exposure alone. V3-V4 metagenomic sequencing revealed Pseudomonas, Aeromonas and Plesiomonas genera dominated in As or F treated groups while As+F treated group was enriched in beneficial Lactococcus and Streptococcus genera. Functional KEGG analysis demonstrated treatment-specific changes in bacterial metabolism, host organismal systems, human diseases, as well as cellular processes of microbial community were significantly affected. When Aeromonas sp. isolated from F-treated fish gut, tagged with GFP-vector and fed (~3.2 × 106 CFU/mL) to untreated fish, induced oxidative stress in gut and kidney. Gut bacteria were found to both increase and mitigate iAs or F-toxicity, whereas As+F treatment promoted a protective response. Correlation analysis between gut microbial community at genus level and oxidative stress parameters of gut and kidney, showed Aeromonas and Plesiomonas genera are strongly correlated with oxidative stress (r = 0.5-0.9, p˂0.05). This study identifies microbiome biomarkers of iAs and F toxicity on gut-kidney axis.

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.

Combined toxicity of perfluoroalkyl substances and microplastics on the sentinel species Daphnia magna: Implications for freshwater ecosystems

Persistent chemicals from industrial processes, particularly perfluoroalkyl substances (PFAS), have become pervasive in the environment due to their persistence, long half-lives, and bioaccumulative properties. Used globally for their thermal resistance and repellence to water and oil, PFAS have led to widespread environmental contamination. These compounds pose significant health risks with exposure through food, water, and dermal contact. Aquatic wildlife is particularly vulnerable as water bodies act as major transport and transformation mediums for PFAS. Their co-occurrence with microplastics may intensify the impact on aquatic species by influencing PFAS sorption and transport. Despite progress in understanding the occurrence and fate of PFAS and microplastics in aquatic ecosystems, the toxicity of PFAS mixtures and their co-occurrence with other high-concern compounds remains poorly understood, especially over organisms' life cycles. Our study investigates the chronic toxicity of PFAS and microplastics on the sentinel species Daphnia, a species central to aquatic foodwebs and an ecotoxicology model. We examined the effects of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and polyethylene terephthalate microplastics (PET) both individually and in mixtures on Daphnia ecological endpoints. Unlike conventional studies, we used two Daphnia genotypes with distinct histories of chemical exposure. This approach revealed that PFAS and microplastics cause developmental failures, delayed sexual maturity and reduced somatic growth, with historical exposure to environmental pollution reducing tolerance to these persistent chemicals due to cumulative fitness costs. We also observed that the combined effect of the persistent chemicals analysed was 59% additive and 41% synergistic, whereas no antagonistic interactions were observed. The genotype-specific responses observed highlight the complex interplay between genetic background and pollutant exposure, emphasizing the importance of incorporating multiple genotypes in environmental risk assessments to more accurately predict the ecological impact of chemical pollutants.

Characterization and risk assessment of microplastics pollution in Mohamaya Lake, Bangladesh

Microplastics (MPs) have recently gained attention as emerging environmental contaminants, yet knowledge of their distribution, sources, and risks in freshwater lakes remains limited. This study examined the occurrence and risk of MPs in water and sediment samples from eight locations in Mohamaya Lake (Bangladesh) collected in April and May 2023. MPs were identified using stereomicroscopy and FTIR, revealing concentrations of 20-95 particles/L in water and 550-1900 particles/kg (d.w.) in sediment, with mean values of 50.62 ± 9.95 particles/L and 1068.75 ± 521.49 particles/kg (d.w.). Dominant MPs were blue fibers, 0-0.5 mm in size, with HDPE, PET and LDPE as the most common polymers. This study used four indices (nemerow pollution index-NPI, contamination factor-CF, pollution load index-PLI, and polymer hazard index-PHI) to assess MP pollution, revealing light to high contamination levels. While NPI indicated light pollution, CF, PLI, and PHI highlighted areas of moderate to high risk, with certain polymers showing high to extreme toxicity. This study deepens understanding of MP contamination in Bangladesh's freshwater lakes, underscoring the need for research on ecotoxicology, regulation, and associated challenges.

Evaluating the impact of the combined acute toxicity of iron (Fe) and microplastics on Namalycastis jaya

The rising concern over heavy metals (HMs) and microplastics (MPs) pollution in marine ecosystems, primarily driven by anthropogenic activities, poses significant threats to ecological health. Understanding the combined exposure of HMs and MPs aids in toxicity assessment. In this study, we examined the combined effects of polystyrene microplastics (MPs) and iron (Fe) on oxidative stress, bioaccumulation, histopathology, and genotoxicity in Namalycastis jaya. Oxidative stress was assessed by analyzing the levels of Superoxide dismutase (SOD), Catalase (CAT), Peroxidase (POD), Malondialdehyde (MDA), and Bicinchoninic acid (BCA), while genotoxicity was evaluated using the comet assay. Bioaccumulation analysis, conducted via Inductively coupled plasma-optical emission spectrometry (ICP-OES), indicated that the highest values (4.790 µg/ml) were observed in combined exposure, emphasizing the significant increase in iron (Fe) accumulation in polychaetes facilitated by MPs. Biochemical analysis revealed that oxidative damage in polychaetes became evident within 48 h of exposure to individual contaminants. However, in the case of combined exposures, elevated stress levels were observed within just 24 h. The genotoxic assay further demonstrated a higher degree of DNA damage in the combined exposure compared to individual exposures. Similarly, histopathology revealed mild alterations in the gut epithelium in combined exposures. It is evident that MPs intensify both oxidative and DNA damage induced by Fe in polychaetes. The insights gained from this study provide valuable information for the risk assessment of Fe and MPs in environmental safety, contributing to our understanding of the complex interactions between these pollutants in marine ecosystems.

Pulse exposure to microplastics depolarizes the goldfish gill: Interactive effects of DOC and differential degradation

Microplastics (MPs) are constantly degrading while moving through aquatic systems as a result of mechanical abrasion, thermal fluctuations, UV light, and chemical exposure. As such, fish may experience pulse exposures to differentially degraded plastics. This study addresses how pulse exposures, over the course of minutes, to differentially degraded microplastics alters a key ionoregulatory property of the goldfish gill. We used transepithelial potential (TEP) across the gills, a diffusion potential resulting from the differential permeability of cations versus anions, as a sensitive indicator of potential ionoregulatory effects. Virgin (non-degraded) MPs along with mechanically, UV, and thermally degraded plastics immediately depolarized the gills (less negative TEP), whereas chemically degraded MPs resulted in no change to TEP. To further explore the physicochemical interaction between the surface of the gill and MPs, combinations of MPs and a single source of dissolved organic carbon (DOC) were tested and revealed that the presence of DOC negated the effects of MPs at the gill regardless of whether DOC or MPs were introduced first. This study suggests that while MPs have the ability to cause ionoregulatory effects at the gill, the effects of ambient water quality, specifically the presence of DOC, are of greater influence.

Polyamide microplastics can mitigate the effects of pathogenic bacterium on the health of marine mussels

Vibrio parahaemolyticus and microplastics are prevalent in the ocean. Bacteria attach onto plastic particles, forming harmful biofilms that collectively threaten bivalve health. This study investigates the interaction between polyamide microplastics (PA: particle size 38 ± 12 µm) and V. parahaemolyticus, as well as their combined impact on thick-shelled mussels (Mytilus coruscus). We introduced 1011 CFU/L of V. parahaemolyticus into varying PA concentrations (0, 5, 50, and 500 particles/L) to observe growth over 14 h and biofilm formation after 48 h. Our findings indicate that microplastics suppress biofilm formation and virulence gene expression. Four treatments were established to monitor mussel responses: a control group without PA or V. parahaemolyticus; a group with 50 particles/L PA; a group with 1011 CFU/L V. parahaemolyticus; and a co-exposure group with both 50 particles/L PA and 1011 CFU/L V. parahaemolyticus, over a 14-day experiment. However, combined stress from microplastics and Vibrio led to immune dysregulation in mussels, resulting in intestinal damage and microbiome disruption. Notably, V. parahaemolyticus had a more severe impact on mussels than microplastics alone, yet their coexistence reduced some harmful effects. This study is the first to explore the interaction between microplastics and V. parahaemolyticus, providing important insights for ecological risk assessments.

Perspectives on the Toxic Effects of Micro- and Nanoplastics on the Environment: A Bibliometric Analysis of the 2014 to 2023 Period

Over the past decade, micro- and nanoplastics (MNPs) have garnered significant attention due to their frequent detection in and potential toxic effects on the environment and organisms, making them a serious threat to human health. To comprehensively understand the research on MNPs' toxicity, we employed the R language-based Bibliometrix toolkit (version 4.3.0), VOSviewer (version 1.6.11) and CiteSpace (version 6.3.R1) to perform statistical and visual analyses of 3541 articles pertaining to MNPs' toxicity between 2014 and 2023, which were retrieved from the Web of Science Core Collection (WOSCC) database. The analysis revealed that research related to MNPs' toxicity has experienced a rapid increase in recent years. China's particularly prominent influence in the field of MNPs' toxicity is evidenced by its academic exchanges and the establishment of a mature cooperation system with other countries (regions), such as the USA and Germany. Studies related to MNPs' toxicity are primarily published in leading journals, including the Science of the Total Environment, Environmental Pollution, and the Journal of Hazardous Materials. The Chinese Academy of Sciences was identified as the leading institution in terms of research on MNPs' toxicity, contributing 203 papers to the total number of studies published. Keyword co-occurrence and burst analyses indicated that the current research on MNPs' toxicity mainly focuses on the toxic effects of MNPs on aquatic organisms, the combined toxicity of MNPs and other contaminants, and the toxic effects and mechanisms of MNPs. Future research should integrate computational toxicology and toxicomics to enhance our understanding of MNPs' toxicity mechanisms and assess the potential health risks posed by atmospheric MNPs.

Understanding and addressing microplastic pollution: Impacts, mitigation, and future perspectives

Improper disposal of household and industrial waste into water bodies has transformed them into de facto dumping grounds. Plastic debris, weathered on beaches degrades into micro-particles and releases chemical additives that enter the water. Microplastic contamination is documented globally in both marine and freshwater environments, posing a significant threat to aquatic ecosystems. The small size of these particles makes them susceptible to ingestion by low trophic fauna, a trend expected to escalate. Ingestion leads to adverse effects like intestinal blockages, alterations in lipid metabolism, histopathological changes in the intestine, contributing to the extinction of vulnerable species and disrupting ecosystem balance. Notably, microplastics (MPs) can act as carriers for pathogens, potentially causing impaired reproductive activity, decreased immunity, and cancer in various organisms. Studies have identified seven principal sources of MPs, including synthetic textiles (35%) and tire abrasion (28%), highlighting the significant human contribution to this pollution. This review covers various aspects of microplastic pollution, including sources, extraction methods, and its profound impact on ecosystems. Additionally, it explores preventive measures, aiming to guide researchers in selecting techniques and inspiring further investigation into the far-reaching impacts of microplastic pollution, fostering effective solutions for this environmental challenge.

Plastic particle impacts on the cardiovascular system and angiogenesis potential

The extensive application of plastics in different sectors such as packaging, building, textiles, consumer products, and several industries has increased in recent years. Emerging data have confirmed that plastic wastes and segregates are problematic issues in aquatic and terrestrial ecosystems. The decomposition of plastic particles (PPs) leads to the release of microplastics (MPs) and nanoplastics (NPs) into the surrounding environment and entry of these particles will be problematic in unicellular and multicellular creatures. It was suggested that PPs can easily cross all biological barriers and reach different organs, especially the cardiovascular system, with the potential to modulate several molecular pathways. It is postulated that the direct interaction of PPs with cellular and subcellular components induces genotoxicity and cytotoxicity within the cardiovascular system. Meanwhile, being inert carriers, PPs can intensify the toxicity of other contaminants inside the cardiovascular system. Here, in this review article, several underlying mechanisms related to PP toxicity in the cardiovascular system were discussed in detail.

Effect of emerging pollutants on the gut microbiota of freshwater animals: Focusing on microplastics and pesticides

In recent years, emerging environmental pollutants have increasingly endangered the health of freshwater organisms. The gut microbiota exhibits sensitivity to medications, dietary factors and environmental pollutants, rendering it a novel target for toxicological studies. The gut microbiota can be a potential exposure route affecting the host's health. Herein, we review the current knowledge on two different but concurrent pollutants, microplastics and pesticides, regarding their impact on the gut microbiota, which includes alterations in microbial composition, gene expression, function, and health effects in the hosts. Moreover, synergetic interactions between microplastics and pesticides can exacerbate dysbiosis and health risks. We discuss health-related implications of gut microbial changes based on the consequences in metabolism, immunity, and physiology function. Further research is needed to discover the mechanisms underlying these effects and develop strategies for mitigating their harmful impacts on freshwater animals.

Neurotoxicity of Some Environmental Pollutants to Zebrafish

The aquatic environment encompasses a wide variety of pollutants, from plastics to drug residues, pesticides, food compounds, and other food by-products, and improper disposal of waste is the main cause of the accumulation of toxic substances in water. Monitoring, assessing, and attempting to control the effects of contaminants in the aquatic environment are necessary and essential to protect the environment and thus human and animal health, and the study of aquatic ecotoxicology has become topical. In this respect, zebrafish are used as model organisms to study the bioaccumulation, toxicity, and influence of environmental pollutants due to their structural, functional, and material advantages. There are many similarities between the metabolism and physiological structures of zebrafish and humans, and the nervous system structure, blood-brain barrier function, and social behavior of zebrafish are characteristics that make them an ideal animal model for studying neurotoxicity. The aim of the study was to highlight the neurotoxicity of nanoplastics, microplastics, fipronil, deltamethrin, and rotenone and to highlight the main behavioral, histological, and oxidative status changes produced in zebrafish exposed to them.

The odd couple: Caffeine and microplastics. Morphological and physiological changes in Mytilus galloprovincialis

In recent years, the presence of pharmaceuticals and microplastics (MPs) in aquatic ecosystems has raised concerns about their environmental impact. This study explores the combined effects of caffeine, a common pharmaceutical pollutant, and MPs on the marine mussel Mytilus galloprovincialis. Caffeine, at concentrations of 20.0 μg L-1, and MPs (1 mg L-1, 35-50 μm size range), was used to mimic real-world exposure scenarios. Two hundred M. galloprovincialis specimens were divided into four groups: caffeine, MPs, Mix (caffeine + MPs), and Control. After a two-week acclimation period, the mollusks were subjected to these pollutants in oxygen-aerated aquariums under controlled conditions for 14 days. Histopathological assessments were performed to evaluate gill morphology. Cellular volume regulation and digestive gland cell viability were also analyzed. Exposure to caffeine and MPs induced significant morphological changes in M. galloprovincialis gills, including cilia loss, ciliary disk damage, and cellular alterations. The chitinous rod supporting filaments also suffered damage, potentially due to MP interactions, leading to hemocyte infiltration and filament integrity compromise. Hemocytic aggregation suggested an inflammatory response to caffeine. In addition, viability assessments of digestive gland cells revealed potential damage to cell membranes and function, with impaired cell volume regulation, particularly in the Mix group, raising concerns about nutrient metabolism disruption and organ function compromise. These findings underscore the vulnerability of M. galloprovincialis to environmental pollutants and emphasize the need for monitoring and mitigation efforts. RESEARCH HIGHLIGHTS: The synergy of caffeine and microplastics (MPs) in aquatic ecosystems warrants investigation. MPs and caffeine could affect gill morphology of Mytilus galloprovincialis. Caffeine-exposed cells had lower viability than the control group in the NR retention test. MPs and mix-exposed cells struggled to recover their volume.

Screening of organic chemicals associated to virgin low-density polyethylene microplastic pellets exposed to the Mediterranean Sea environment by combining gas chromatography and liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry

In this work, organic chemicals associated with microplastics (MPs) exposed to a coastal anthropogenized environment for up to eight weeks have been screened for, in order to discern the (de)sorption dynamics of chemicals in the marine ecosystem. Low-density polyethylene (LDPE) pellets were studied since they represent primary MPs used by the plastic industry and a relevant input of MPs into the oceans. To maximize the coverage of chemicals that could be detected, both liquid and gas chromatography coupled to quadrupole-time-of-flight (GC-QTOF and LC-QTOF, respectively) were used. In the case of LC-QTOF, an electrospray ionization source was employed, and the compounds were investigated by combining suspect and non-target screening workflows. The GC-QTOF was equipped with an electron ionization source and compounds were screened in raw and derivatized (silylated) extracts by deconvolution and contrast to high- and low-resolution libraries. A total of 50 compounds of multifarious classes were tentatively identified. Among them, melamine and 2-ethylhexyl salicylate (EHS) were detected in the original MPs but were rapidly desorbed. Melamine was completely released into the marine environment, while EHS was partly released but a portion remained bound to the MPs. On the other hand, many other chemicals of both anthropogenic (e.g. phenanthrene or benzophenone) and natural origin (e.g. betaine and several fatty acids) accumulated onto MPs over time. Quantification of 12 unequivocally identified chemicals resulted into a total concentration of 810 μg/kg after MPs exposure for 8 weeks.

Microplastics as an emerging threat to amphibians: Current status and future perspectives

Given their pervasiveness in the environment, particularly in aquatic ecosystems, plastics are posing a growing concern worldwide. Many vertebrates and invertebrates in marine, freshwater, and terrestrial ecosystems exhibit microplastic (MP) uptake and accumulation. Some studies have indicated the fatal impacts of MPs on animals and their possible transfer through food chains. Thus, it is crucial to study MP pollution and its impacts on environment-sensitive and globally threatened animal groups, such as amphibians, which also play an important role in the energy transfer between ecosystems. Unfortunately, research in this field is lacking and sources of organized information are also scarce. Hence, we systematically reviewed published literature on MPs in amphibians to fill the existing knowledge gap. Our review revealed that most of the previous studies have focused on MP bioaccumulation in amphibians, whereas, only a few research highlighted its impacts. We found that more than 80% of the studied species exhibited MP accumulation. MPs were reported to persist in different organs for a long time and get transferred to other trophic levels. They can also exhibit cytotoxic and mutagenic effects and may have fatal impacts. Moreover, they can increase the disease susceptibility of amphibians. Our study concludes the MPs as a potential threat to amphibians and urges increasing the scope and frequency of research on MP pollution and its impacts on this vulnerable animal group. We also provide a generalized method for studying MPs in amphibians with future perspectives and research directions. Our study is significant for extending the knowledge of MPs and their impacts on amphibians and guiding prospective research.

What do we know about plastic pollution in Brazilian aquatic ecosystems?

Due to the increasing use and inadequate disposal of plastic by humans, aquatic environments have become receptacles for pollutants such as plastic. This study aimed to perform an analysis of plastic particles pollution in Brazilian aquatic ecosystems with special attention to inland aquatic environments and fish in order to identify information gaps in this field. Manuscripts published in the last 21 years and indexed in the Web of Science database were consulted. A total of 185 met the proposed inclusion criteria, such as having empirical data, being conducted in Brazil, and dealing with plastic pollution. In general, the number of studies increases over the years, and this increasing number of publications is accompanied by declared financial support; the Southeast and Northeast regions are the regions that publish the most on the topic, with São Paulo, Rio de Janeiro, and Pernambuco being the main states; the main focus of the studies is the detection of plastic particles mainly in biota (51%) and sediment (34%), and the most frequent ecosystem is the marine (89%); regarding the taxa, the majority is about plastic detection in fish (75%). Only 18% of the papers studying fishes consider their bio-ecological data, and only 17% of the manuscripts carried out the chemical characterization of the particles. However, 99% of the papers considered the shape of the plastic particle. We emphasize the need for more research and grants for studies with Brazilian inland aquatic ecosystems on the effects of plastic particle pollution on freshwater fish. Regional and national research funding agencies are very important to encourage an increase in the number of grants and specific calls for studies on plastic pollution and its impact on freshwater biota, considering the different macro-regions in Brazil, especially in the northern region.

Assessing microplastics contamination in unviable loggerhead sea turtle eggs

Sea turtles, in comparison with marine mammals, sea birds, and fishes, are the most affected by microplastics in terms of number of individuals impacted and concentration within each organism. The ubiquitous nature and persistence of microplastics in the environment further compromises sea turtles as many species are currently vulnerable, endangered, or critically endangered. The objective of this study was to quantify microplastic contamination in unviable loggerhead sea turtle eggs (Caretta caretta). Eggs were collected from seven locations along the northwest coast of Florida. A total of 70 nests and 350 eggs were examined. Microplastics (n = 510) were found in undeveloped loggerhead sea turtle eggs across all seven sites, suggesting that maternal transference and/or exchange between the internal and external environment were possible. The frequency found was 7.29 ± 1.83 microplastic pieces per nest and 1.46 ± 0.01 per egg. Microplastics were categorized based on color, shape, size, and type of polymer. The predominant color of microplastics were blue/green (n = 236), shape was fibers (n = 369), and length was 10-300 μm (n = 191). Identified fragments, films, beads and one foam (n = 187) had the most common area of 1-10 μm2 (n = 45). Micro-Fourier Transform Infrared (μ-FTIR) spectroscopy analysis demonstrated that polyethylene (11 %) and polystyrene (7 %) were the main polymer types. For the first time microplastics were found in unviable, undeveloped loggerhead sea turtle eggs collected in northwest Florida. This work provides insight into the distribution patterns of microplastic pollutants in loggerhead sea turtle eggs and may extend to other species worldwide.

Various additive release from microplastics and their toxicity in aquatic environments

Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.

Effect of polypropylene microplastics on virus resistance in spotted sea bass (Lateolabrax maculatus)

Microplastics (MPs) pollution is a hot issue of global concern. Polypropylene microplastics (PP-MPs) age quickly in the marine environment and break down into smaller particles because of their relatively low temperature resistance, poor ultraviolet resistance, and poor antioxidant capacity, making them one of the major pollutants in the ocean. We assessed whether long-term exposure to micron-sized PP-MPs influences fish susceptibility to viral diseases. We found that exposure to PP-MPs (1-6 μm and 10-30 μm) at concentrations of 500 and 5000 μg/L resulted in uptake into spleen and kidney tissues of Lateolabrax maculatus. Increased activation of melanomacrophage centers was visible in histopathological sections of spleen from fish exposed to PP-MPs, and greater deterioration was observed in the spleen of fish infected by largemouth bass ulcerative syndrome virus after PP-MPs exposure. Additionally, exposure to PP-MPs led to significant cytotoxicity and a negative impact on the antiviral ability of cells. PP-MPs exposure had inhibitory or toxic effects on the immune system in spotted sea bass, which accelerated virus replication in vivo and decreased the expression of the innate immune- and acquired immune related genes in spleen and kidney tissues, thus increasing fish susceptibility to viral diseases. These results indicate that the long-term presence of micron-sized PP-MPs might impact fish resistance to disease, thereby posing a far-reaching problem for marine organisms.

Emergence of nanoplastics in the aquatic environment and possible impacts on aquatic organisms

Plastic production on a global scale is instrumental in advancing modern society. However, plastic can be broken down by mechanical and chemical forces of humans and nature, and knowledge of the fate and effects of plastic, especially nanoplastics, in the aquatic environment remains poor. We provide an overview of current knowledge on the environmental occurrence and toxicity of nanoplastics, and suggestions for future research. There are nanoplastics present in seas, rivers, and nature reserves from Asia, Europe, Antarctica, and the Arctic Ocean at levels of 0.3-488 microgram per liter. Once in the aquatic environment, nanoplastics accumulate in plankton, nekton, benthos through ingestion and adherence, with multiple toxic results including inhibited growth, reproductive abnormalities, oxidative stress, and immune system dysfunction. Further investigations should focus on chemical analysis methods for nanoplastics, effect and mechanism of nanoplastics at environmental relevant concentrations in aquatic organisms, as well as the mechanism of the Trojan horse effect of nanoplastics.

Are fishes selecting the trash they eat? Influence of feeding mode and habitat on microplastic uptake in an artificial reef complex (ARC)

Every year, coastal countries generate ∼275 million tons of plastic, and the oceans receive from 4.8 to 12.7 million tons3. Pollution by synthetic polymers is even more problematic for the environment when this material is fragmented into small portions, forming microplastics (MPs). In the present study, we analyze the selection of MPs by the ichthyofauna based on the availability of the morphotypes and polymeric composition of microplastic in the environment and compare the amount of MP in surface water, water column, sediments and fish in different organs, trophic categories, habitats and areas with and without artificial reefs. In order to achieve this goal, the shape, color, abundance and chemical composition of MPs in the digestive tract and gills of 18 fish species in artificial reefs area and control area, were evaluated. A total of 216 fish were analyzed, and 149 (60 %) had MPs in at least one organ and showed a mean concentration of 1.55 ± 3.31 MPs/g. Of the 18 fish species collected in the reef complex area, 17 (94 %) included individuals with at least one MP in digestive tract or gills. Four species showed the higher selectivity of MP types, colors, and polymers. More MPs were found in the fish, surface water, water column and sediment in the artificial reef area compared to the control areas. This is the first evidence of MP selection by commercially important fish species in artificial marine structures worldwide. These results provide useful information on MP pollution in RAs and highlight yet another issue that must be considered in the management of fisheries resources in the region and in other reef complexes around the world.

Medicine designed to combat diseases of affluence affects the early development of fish. How do plastic microparticles contribute?

The incidence of diseases of affluence, such as diabetes mellitus, cardiovascular diseases, high blood pressure, and high cholesterol has been reported to rise. Consequently, the concentrations of residues of drugs designed to treat these diseases have been rising in water bodies. Moreover, the toxicity of these pharmaceuticals towards fish and other non-target organisms can be even enhanced by microplastic particles that are reportedly present in surface water. Therefore, the aim of this study was to describe the effects of three highly prescribed drugs, in particular metoprolol, enalapril, and metformin on fish early-life stages. Also, it was hypothesized that polystyrene microparticles will increase the toxicity of metoprolol to fish early-life stages. Embryonal acute toxicity tests on Danio rerio and Cyprinus carpio were carried out in order to describe the possible toxic effects of metoprolol, enalapril, and metformin. Also, the acute toxicity of polystyrene microparticles and the combination of metoprolol with polystyrene microparticles were tested on D. rerio embryos. Additionally, a 31-day long embryo-larval subchronic toxicity test was carried out with C. carpio in order to describe the long-term effects of low concentrations of metoprolol. The results of the study show that both metoprolol and enalapril have the potential to disrupt the early development of the heart in the embryonal stages of fish. Also, enalapril and metformin together with polystyrene microparticles seem to possibly disrupt the reproduction cycle and act as endocrine disruptors. Both pure polystyrene microparticles and the combination of them with metoprolol affect inflammatory processes in organisms. Additionally, metformin alters several metabolism pathways in fish early-life stages. The results of the study bring new evidence that even low, environmentally-relevant concentrations of pharmaceuticals have the potential to disrupt the early development of fish, particularly on a molecular level.

Ecotoxicological insights: Effects of pesticides on ionic metabolism regulation in freshwater catfish, Mystus keletius

Fish maintain their body fluid ionic and osmotic homeostasis using sophisticated iono-/osmoregulation mechanisms through gills ionocytes. Pesticide-induced ionic imbalance in fish has been recognized as a valuable tool to determine its toxic effects. Acute exposure to synthetic and organo-chemical pesticides on the regulation of ionic (Na+, Ca2+, P) metabolism in freshwater catfish Mystus keletius was evaluated. Fish were exposed to sub-lethal concentrations (mg/l) of selected pesticide for a period of 7, 14, 21 and 28 days. Results indicated that chemical pesticides - Impala and Ekalux - evoked adverse toxic effects on selected tissues compared to organo-chemical pesticide tested. Statistical analysis of the summative data using two-way ANOVA was significant (p-value<0.001). Variations in the cellular parameters analysed were attributed to the physiological acclimatization of fish to the pesticide exposed. Based on the results it is concluded that organic pesticides may be preferred for rice field application considering safety aspects.

Plastics in an endemic fish species (Alburnus sellal) and its parasite (Ligula intestinalis) in the Upper Tigris River, Türkiye

Occurrence of micro-, meso- and macroplastics in Alburnus sellal and its parasite Ligula intestinalis is reported for the first time in the Tigris River, one of the two large rivers that defines Mesopotamia. Plastic occurrence was assessed from museum fish materials collected in the upper Tigris River between 2007 and 2021. Plastics were found in 57 % of A. sellal specimens (536 individuals) and in 74 % of L. intestinalis specimens (57 individuals). Mean plastic ingestion was 1.27 ± 1.30 items. fish-1 and 1.77 ± 1.79 items. parasite-1 considering all the fish and parasites analysed. Fibres were the most common types of plastics, comprising 96.2 % and 81 % of plastics in A. sellal and L. intestinalis, respectively. Black was the most common colour of plastics found in both fish (37 %) and parasite specimens (58 %). Microplastics comprised 95.5 % and 100 % of plastics found in A. sellal and L. intestinalis, respectively. In both specimens acrylic (PAN) was the most common polymer as confirmed by FTIR spectroscopy. Differences in plastic ingestion were not significantly over time and among regions. No significant correlation was found between plastics ingestion by fish and by parasites. The present assessment shows that native fish species of the Tigris River have been contaminated by plastics by more than a decade. Our results contribute to a better understanding of the status of plastic pollution in fish and parasites, provide plastic pollution baseline data for the Tigris River and highlight the urgent need to elucidate on the distribution and fate of plastics in freshwater environments and their effects on the ecosystem and humans.

Aggregation in experimental studies with microparticles: Experimental settings change particle size distribution during exposure

The ubiquitous occurrence of microplastics is raising broad concerns and motivating effect studies. In these studies, however, particle behaviour in the water and aggregation are rarely considered leading to contradictory results reported by different studies. Using an environmentally relevant experimental setup with Daphnia magna as a test organism, we investigated how experimental conditions affect particle aggregation and the aggregate heterogeneity in terms of the particle size distribution. The experimental factors considered were (1) exposure duration (48 h vs 120 h), (2) the total mass of suspended solids (0-10 mg/l) composed of natural mineral particles (kaolin) and microplastics, (3) the proportion of the microplastics in the particle suspension (0-10% by mass), (4) dissolved organic matter (DOM; 0 vs 20 mg agarose/l), and (5) presence of the test organism (0 and 5 daphnids/vial). We found that particle aggregation occurs within the first 48 h of incubation in all treatments, no substantial change in the aggregate heterogeneity is observed afterwards. The median aggregate size was ∼2-fold higher than the nominal average particle size of clay and microplastics in the stock suspensions used to prepare the experimental mixtures. The strongest positive driver of the aggregate size and heterogeneity was DOM, followed by the presence of daphnids and the concentration of the suspended solids in the system. Also, microplastics were found to facilitate aggregation, albeit they were the weakest contributor. Moreover, besides directly increasing the aggregation, DOM relaxed the effects of the total solids and daphnids on the aggregate size. Thus, the particle size distribution was established early during the exposure and shaped by all experimental factors and their interactions. These findings improve our understanding of the processes occurring in the exposure systems when conducting effect studies with microplastics and other particulates and demonstrate the necessity to access the particle size distribution to characterise the exposure. Aslo, relevant experimental designs with microplastics must include relevant natural particulates and DOM to ensure environmentally realistic particle behaviour and adequate particle-biota interactions.

Exploring the combined interplays: Effects of cypermethrin and microplastic exposure on the survival and antioxidant physiology of Astacus leptodactylus

Plastic waste and micro/nanoplastic particles pose a significant global environmental challenge, along with concerns surrounding certain pesticides' impact on aquatic organisms. This study investigated the effects of microplastic particles (MPPs) and cypermethrin (CYP) on crayfish, focusing on biochemical indices, lipid peroxidation, oxidative stress, hematological changes, and histopathological damage. After determining the LC50-96 h value (4.162 μg/L), crayfish were exposed to sub-lethal concentrations of CYP (1.00 ppb (20%) and 2.00 ppb (50%)) and fed a diet containing 100 mg/kg MPPs for 60 days. Hemolymph transfusion and histopathological examinations of the hepatopancreas were conducted. The results showed significant alterations in crayfish. Total protein levels decreased, indicating protein breakdown to counteract contaminants, while total cholesterol and triglyceride levels declined, suggesting impaired metabolism. Glucose levels increased in response to chemical stress. The decline in total antioxidant capacity highlighted the impact of prolonged xenobiotic exposure and oxidative stress, while increased CAT, SOD, and MDA activities helped mitigate oxidative stress and maintain cellular homeostasis. The elevated total hemocyte count, particularly in semi-granular cells, suggests their active involvement in the detoxification process. Further research is needed to fully understand the implications of these effects.

Microplastic ingestion and its effects οn sea urchin Paracentrotus lividus: A field study in a coastal East Mediterranean environment

Microplastics (MPs) are recognized as an increasing threat to the marine environment, but little is known about their effects on benthic organisms, including sea urchins, when ingested. For this purpose, wild sea urchins (P. lividus) and seafloor sediment samples were investigated across three coastal areas of Zakynthos Island (Ionian Sea), each exposed to different anthropogenic pressures, revealing a consistent pattern in MP abundance, shape, and color. Biomarkers related to oxidative stress, neurotoxicity, and genotoxicity showed no significant effects of MP ingestion in the sea urchins, except for a positive correlation between GST activity and ingested MPs, suggesting a possible activation of their detoxification system in response to MP ingestion. While MP concentrations in sea urchins and sediments were within the low range reported in the global literature, it remains crucial to conduct further investigations in areas with MP pollution approaching predicted levels to fully comprehend the potential effects of MP pollution on marine organisms.

Journey of micronanoplastics with blood components

The entry of micro- and nanoplastics (MNPs) into the human body is inevitable. They enter blood circulation through ingestion, inhalation, and dermal contact by crossing the gut-lung-skin barrier (the epithelium of the digestive tract, the respiratory tract, and the cutaneous layer). There are many reports on their toxicities to organs and tissues. This paper presents the first thorough assessment of MNP-driven bloodstream toxicity and the mechanism of toxicity from the viewpoint of both MNP and environmental co-pollutant complexes. Toxic impacts include plasma protein denaturation, hemolysis, reduced immunity, thrombosis, blood coagulation, and vascular endothelial damage, among others, which can lead to life-threatening diseases. Protein corona formation, oxidative stress, cytokine alterations, inflammation, and cyto- and genotoxicity are the key mechanisms involved in toxicity. MNPs change the secondary structure of plasma proteins, thereby preventing their transport functions (for nutrients, drugs, oxygen, etc.). MNPs inhibit erythropoiesis by influencing hematopoietic stem cell proliferation and differentiation. They cause red blood cell and platelet aggregation, as well as increased adherence to endothelial cells, which can lead to thrombosis and cardiovascular disease. White blood cells and immune cells phagocytose MNPs, provoking inflammation. However, research gaps still exist, including gaps regarding the combined toxicity of MNPs and co-pollutants, toxicological studies in human models, advanced methodologies for toxicity analysis, bioaccumulation studies, inflammation and immunological responses, dose-response relationships of MNPs, and the effect of different physiochemical characteristics of MNPs. Furthermore, most studies have analyzed toxicity using prepared MNPs; hence, studies must be undertaken using true-to-life MNPs to determine the real-world scenario. Additionally, nanoplastics may further degrade into monomers, whose toxic effects have not yet been explored. The research gaps highlighted in this review will inspire future studies on the toxicity of MNPs in the vascular/circulatory systems utilizing in vivo models to enable more reliable health risk assessment.

First record of microplastic in the Brazilian sea hare Aplysia brasiliana Rang, 1828 (Mollusca: Aplysiidae)

The presence of plastic debris in the marine environment has reached massive levels in the past decades. In marine environments, microplastics can exist for hundreds of years and the presence of microplastics in this environment has been reported since 1970 and since then has been considered ubiquitous. Mollusks are being used as microplastic pollution indicators, especially in coastal areas and bivalves are more often used in microplastic-monitoring studies. On the other hand, gastropods are poorly used as indicators for microplastic pollution, even though they are the most diverse group of mollusks. The sea hares of the genus Aplysia are herbivorous gastropods, important model organisms commonly used in neuroscience studies, isolating the compounds in their defensive ink. Until today, there is no previous record of the presence of MPs in Aplysia gastropods. Therefore, this study aims to investigate the presence of microplastics in tissues of A. brasiliana found in southeastern Brazil. We collected seven individuals of A. brasiliana from a beach in southeastern Brazil, dissected them to isolate the digestive tract and the gills, and digested the tissues with a solution of 10 % NaOH. In the end, 1021 microplastic particles were found, 940 in the digestive tissue, and 81 in the gills. These results represent the first record of the presence of microplastics in the Brazilian sea hare A. brasiliana.

Interaction of antidiabetic formulation with nanoplastics and its binary influence on plasma protein

Nanoplastics exposure to humans becomes inevitable due to its prevalence and permanence. Adsorption of emerging pollutant metformin hydrochloride (Met-HCl) -antidiabetic drug, on polystyrene nanoplastics (PSNPs) and influence on plasma protein binding was investigated. Fluorescence studies were carried out for human serum albumin (HSA) binding. Adsorption follows pseudo-second-order kinetics, intraparticle-diffusion, and Langmuir isotherm, undergoing both physisorption and chemisorption which was validated by FE-SEM, FTIR, and HRMS measurements. Complex, experiences static quenching mechanism by hydrogen bonding and VanderWaals force of attraction to HSA. FTIR confirms the secondary structural alteration of HSA. Since Met-HCl covers the NPs' surface, NPs' affinity for HSA is reduced and they might reach the target organs of Met-HCl, disrupt antidiabetic mechanisms and cause far-reaching implications. Results from molecular docking and simulation studies backed up these results as hydrophobic and hydrogen bonds dominate the binding process of the HSA-Met-HCl-PSNPs complex. This work will aid in understanding of the toxico-kinetics/dynamics of binary contaminants.

Phthalates and their effects on human health: Focus on erythrocytes and the reproductive system

Plastics, long-chain artificial polymers, are used worldwide with a global production of 350 million tonnes per year. Various degradation processes transform plastics into smaller fragments divided into micro, meso and macroplastics. In various industries, such as construction, certain plastic additives are used to improve flexibility and enhance performance. Plastic additives include phthalates (PAE), dibutyl phthalate (DPB) and diethyl phthalate (DEP). Due to the use of plastics and plastic additives, these small fragments of different shapes and colours are present in all environmental compartments. For their characteristics, PAEs can be introduced particularly by ingestion, inhalation and dermal absorption. They can accumulate in the human body, where they have already been identified in blood, amniotic fluid and urine. The purpose of this review is to gather the effects that these plastic additives have on various systems in the human body. Being endocrine disruptors, the effects they have on erythrocytes and how they can be considered targets for xenobiotics have been analysed. The influence on the reproductive system was also examined. Phthalates are therefore often overused. Due to their properties, they can reach human tissues and have a negative impact on health. The aim of this review is to give an overview of the presence of phthalates and their hazards. Therefore, the use of these plastic additives should be reduced, replaced and their disposal improved.

Assessment of the effects of non-phthalate plasticizer DEHT on the bivalve molluscs Mytilus galloprovincialis

Due to their uncontrolled use, plastics has become an environmental concern, not only for their varying dimension but also for the potential release of substances such as phthalates (PAEs) and non-phthalates (NPPs) into the water. Phthalates are the most common plasticizers of concern, but non-phthalate plasticizers such as di (2-ethylhexyl) terephthalate (DEHT) have also been lately found in the marine environment. Mytilus galloprovincialis is a well-known bioindicator of aquatic environments due to its ability to accumulate a wide variety of xenobiotics, including plasticizers. Hence, aim of this study was to evaluate the potential bioaccumulation and effects of the NPP DEHT on M. galloprovincialis. To this purpose, following exposure to DEHT at 1 mg/l (DEHT1) and 100 mg/l (DEHT100), its accumulation in tissues and its effects on total lipids and fatty acid (FA) composition, protein content, cell viability, ability to recover volume and changes in biomarkers of oxidative stress were assessed. Mussels were able to bioaccumulate DEHT in their tissues, with a statistically significant increase compared to the control organisms. Differences in FA composition were observed after exposure, since C16:0, C18:0, C20:5ω-3 and C22:6ω-3 were significantly decreased from control to exposed groups. As a result, total SFA, MUFA and PUFA were affected in DEHT-exposed groups. Also, total protein varied following DEHT exposure, and significantly decreased in the DEHT100-group. Considering the physiological responses, both DEHT-exposed groups lost their ability to return to the original volume of digestive gland (DG) cells. On the other hand, oxidative biomarkers in the gills and DG were not significantly affected by the DEHT exposure. Overall, this study showed for the first time that DEHT exposure differentially affect mussels, in their lipid and protein metabolism, as well as cellular parameters.

Exploring the Impact of Contaminants of Emerging Concern on Fish and Invertebrates Physiology in the Mediterranean Sea

In this historical context, the Mediterranean Sea faces an increasing threat from emerging pollutants such as pharmaceuticals, personal care products, heavy metals, pesticides and microplastics, which pose a serious risk to the environment and human health. In this regard, aquatic invertebrates and fish are particularly vulnerable to the toxic effects of these pollutants, and several species have been identified as bio-indicators for their detection. Among these, bivalve molluscs and elasmobranchs are now widely used as bio-indicators to accurately assess the effects of contaminants. The study focuses on the catshark Scyliorhinus canicular and on the Mediterranean mussel Mytilus galloprovincialis. The first one is a useful indicator of localised contamination levels due to its exposure to pollutants that accumulate on the seabed. Moreover, it has a high trophic position and plays an important role in the Mediterranean Sea ecosystem. The bivalve mollusc Mytilus galloprovincialis, on the other hand, being a filter-feeding organism, can acquire and bioaccumulate foreign particles present in its environment. Additionally, because it is also a species of commercial interest, it has a direct impact on human health. In conclusion, the increasing presence of emerging pollutants in the Mediterranean Sea is a serious issue that requires immediate attention. Bivalve molluscs and elasmobranchs are two examples of bio-indicators that must be used to precisely determine the effects of these pollutants on the marine ecosystem and human health.

Cadmium induced bioaccumulation, histopathology, gene regulation in fish and its amelioration - A review

Different anthropogenic activities as well as natural sources contribute enormously towards various heavy metal contaminations in aquatic habitats. Cadmium (Cd) is one of most prevalent and toxic heavy metals with a long half life. Unlike terrestrial animals, exposure of Cd in fishes may happen not only through feeds but also from its habitat water. Bioaccumulation of Cd in fishes occurs in many tissues, but mainly in gill, liver, kidney, skin, and muscle. The concentrations of Cd in fish tissues depend upon the extent and duration of Cd exposure, species and age of fishes, dietary minerals and antioxidant concentrations, and habitat water quality. Specific histopathological observations in liver, kidney, and gill are useful to understand the effects of Cd, which could help to determine the ameliorating methods to be adopted. Exposure of Cd exerts several adverse effects on general growth and development, reproductive processes, osmoregulation, morphological and histological structures, stress tolerance, and endocrine system, mainly due to changes in biological functions induced by differential expressions of several genes related to oxidative stress, apoptosis, inflammation, immunosuppressions, genotoxicity, Cd chelation and carbohydrate metabolism. Chronic biomagnifications of Cd exceeding the permitted level may be harmful not only to the fishes itself but also to humans through food chains. Amelioration of such toxic heavy metal that has been categorized as a potent carcinogenic in humans is of utmost importance. Main modes of amelioration encompas reducing oxidative damages by promoting the antioxidative defenses, decreasing Cd absorption, increasing excretion through excretory system and improving the tolerance of fishes to Cd toxicity. Many amelioration measures such as use of minerals (for example, zinc, calcium, and iron), vitamins (vitamin C, A, and E), different herbs, probiotics and other agents (taurine, bentonite, chitosan, zeolite, and metallothionein) have been explored for their effective roles to reduce Cd bioaccumulation and toxicity symptoms in fishes. The present review discusses bioaccumulation of Cd, histopathological alterations, oxidative stress, synergism-antagonism, and gene regulation in different tissues, and its amelioration measures in fishes.

Impact of Particulate Pollution on Aquatic Invertebrates

A serious global problem, air pollution poses a risk to both human and environmental health. It contains hazardous material like heavy metals, nanoparticles, and others that can create an impact on both land and marine environments. Particulate pollutants, which can enter water systems through a variety of ways, including precipitation and industrial runoff, can have a particularly adverse influence on aquatic invertebrates. Once in the water, these particles can harm aquatic invertebrates physically, physiologically, and molecularly, resulting in developmental problems and multi-organ toxicity. Further research at the cellular and molecular levels in numerous locations of the world is necessary to completely understand the impacts of particle pollution on aquatic invertebrates. Understanding how particle pollution affects aquatic invertebrates is vital as the significance of ecotoxicological studies on particulate contaminants increases. This review gives a comprehensive overview of the current understanding of how particle pollution affects aquatic invertebrates.

Microplastic Presence in the Digestive Tract of Pearly Razorfish Xyrichtys novacula Causes Oxidative Stress in Liver Tissue

Plastic pollution in the oceans is a growing problem, with negative effects on exposed species and ecosystems. Xyrichtys novacula L. is a very important fish species both culturally and economically in the Balearic Islands. The aim of the present study was to detect and categorise the presence of microplastics (MPs) in the digestive tract of X. novacula, as well as the existence of oxidative stress in the liver. For this purpose, the fish were categorised into two groups based on the number of MPs observed in the digestive tracts: a group with no or low presence of MPs (0-3 items) and a group with a higher presence of MPs (4-28 items). MPs were found in 89% of the specimens analysed, with a dominance of fibre type and blue colour. Regarding the type of polymer, polycarbonate was the most abundant, followed by polypropylene and polyethylene. For the group with a greater presence of MPs, the activities of the antioxidant enzymes glutathione peroxidase and glutathione reductase, as well as the phase II detoxification enzyme glutathione s-transferase, were higher than the activities observed in fish with little to no presence of MPs. The activities of catalase and superoxide dismutase and the levels of malondialdehyde did not show significant differences between both groups. In conclusion, these results demonstrate the presence of MPs in the digestive tract of X. novacula and the existence of an antioxidant and detoxification response, mainly based on the glutathione-based enzymes.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

Effects of Single and Combined Ciprofloxacin and Lead Treatments on Zebrafish Behavior, Oxidative Stress, and Elements Content

Even though the toxic effects of antibiotics and heavy metals have been extensively studied in the last decades, their combined adverse impact on aquatic organisms is poorly understood. Therefore, the objective of this study was to assess the acute effects of a ciprofloxacin (Cipro) and lead (Pb) mixture on the 3D swimming behavior, acetylcholinesterase (AChE) activity, lipid peroxidation level (MDA-malondialdehyde), activity of some oxidative stress markers (SOD-superoxide dismutase and GPx-glutathione peroxidase), and the essential elements content (Cu-copper, Zn-zinc, Fe-iron, Ca-calcium, Mg-magnesium, Na-sodium and K-potassium) in the body of zebrafish (Danio rerio). For this purpose, zebrafish were exposed to environmentally relevant concentrations of Cipro, Pb, and a mixture for 96 h. The results revealed that acute exposure to Pb alone and in mixture with Cipro impaired zebrafish exploratory behavior by decreasing swimming activity and elevating freezing duration. Moreover, significant deficiencies of Ca, K, Mg, and Na contents, as well as an excess of Zn level, were observed in fish tissues after exposure to the binary mixture. Likewise, the combined treatment with Pb and Cipro inhibited the activity of AChE and increased the GPx activity and MDA level. The mixture produced more damage in all studied endpoints, while Cipro had no significant effect. The findings highlight that the simultaneous presence of antibiotics and heavy metals in the environment can pose a threat to the health of living organisms.

Dried fish more prone to microplastics contamination over fresh fish - Higher potential of trophic transfer to human body

Globally, microplastics (MPs) contamination in aquatic organisms is emerging as an alarming phenomenon. In the present study, we investigated MPs in three commercially important fishes (Bombay duck Harpadon nehereus, ribbon fish Trichiurus lepturus and hairfin anchovy Setipinna phasa) in fresh and dried conditions collected from two sites (Chattogram and Kuakata) of the Bay of Bengal. It was evident that fresh T. lepturus ingested highest amount of MPs through the gills (6.41 mps/g) from Chattogram followed by in the gastrointestinal tract, GIT (6.20 mps/g) and in the muscle (1.20 mps/g) from Kuakata. Among the fresh fishes, H. nehereus from Kuakata accumulated highest amount of MPs (0.21 mps/g), while S. phasa from Kuakata contained the least amount of MPs (0.06 mps/g). On the other hand, among the dried fishes, T. lepturus from Kuakata contained highest amount of MPs (46.00 mps/g), while S. phasa from Kuakata retained lowest amount of MPs (2.17 mps/g). Strangely, all the dried fishes showed significantly higher amount of MPs compared to fresh fishes from both the locations. Fiber was the most dominant type of shape of MPs which accounted 66 %, followed by fragment (27.38 %), microbeads (3.59 %), film (1.48 %), foam (1.31 %) and pellet (0.25 %). Size-wise, the major portion (39.66 %) of MPs was present to be in size range less than 0.5 mm followed by 37.67 % in the size range of 0.5-1.0 mm group and rest 22.67 % within 1.0-5.0 mm. Red (41.55 %) colored MPs was the most prominent, followed by brown (22.11 %), blue (16.32 %), pink (11.69 %), purple (5.10 %), and green (2.25 %). Among polymer types, low-density polyethylene (LDPE) was the most common (38 %), followed by polystyrene (PS-22 %), polyvinyl chloride (PVC-16 %), polyamide (PA-13 %) and ethylene-vinyl acetate (EVA-9 %). The present study confirms high occurrence of MPs in the dried fishes over the fresh fishes from the Bay of Bengal, with high potential of trophic transfer to the human body.