Nanoplastics impact on marine biota: A review

Melatonin prevents the transgenerational toxicity of nanoplastics in zebrafish (Danio rerio)

As a novel pollutant, microplastic pollution has become a global environmental concern. Melatonin (MT) has a protective effect on the damage caused by pollutants. However, there is still a lack of research on the transgenerational toxicity of microplastics and the alleviation of microplastics toxicity by MT. In this study, the adult zebrafish was exposed to (0, 0.1 and 1 mg/L) polystyrene nanoplastics (PSNP) with or without (1 μM) MT for 14 days, and embryos (F1) were used for experiments. Our study found that long-term exposure of parents to 1 mg/L PSNP reduced fertilization rate and survival rate of offspring, increased the deformity rate and induced embryos to hatch in advance. The growth inhibition of offspring was related to the gene transcription of the growth hormone/insulin-like growth factor axis. Moreover, PSNP caused oxidative stress in offspring, damaged immune system, reduced antioxidant capacity and induced apoptosis. MT supplementation could effectively alleviate the developmental toxicity and oxidative damage of offspring, but the negative effects brought by PSNP could not be completely eliminated. Our research provided a new reference for the protective effect of MT on transgenerational toxicity induced by PSNP.

Polyethylene Micro/Nanoplastics Exposure Induces Epithelial-Mesenchymal Transition in Human Bronchial and Alveolar Epithelial Cells

Micro/nanoplastics (MNPs), which are widely spread in the environment, have gained attention because of their ability to enter the human body mainly through ingestion, inhalation, and skin contact, thus representing a serious health threat. Several studies have reported the presence of MNPs in lung tissue and the potential role of MNP inhalation in triggering lung fibrosis and tumorigenesis. However, there is a paucity of knowledge regarding the cellular response to MNPs composed of polyethylene (PE), one of the most common plastic pollutants in the biosphere. In this study, we investigated the effects of low/high concentrations of PE MNPs on respiratory epithelial cell viability and migration/invasion abilities, using MTT, scratch, and transwell assays. Morphological and molecular changes were assessed via immunofluorescence, Western blot, and qRT-PCR. We demonstrated that acute exposure to PE MNPs does not induce cellular toxicity. Instead, cells displayed visible morphological changes also involving actin cytoskeleton reorganization. Our data underlined the role of epithelial-mesenchymal transition (EMT) in triggering this process. Moreover, a remarkable increase in migration potential was noticed, in absence of a significant alteration of the cell's invasive capacity. The present study highlights the potential impact of PE MNPs inhalation on the human respiratory epithelium, suggesting a possible role in carcinogenesis.

Identification of Pristine and Protein Corona Coated Micro- and Nanoplastic Particles with a Colorimetric Sensor Array

A colorimetric sensor array has been developed to differentiate various micro- and nanoplastic particles (MNPs), both pristine and those coated with a protein corona, in buffered water. This array utilizes five distinct cross-reactive chemo-responsive dyes, which exhibit changes in visible optical absorbance upon interaction with MNPs. Although no single dye responds exclusively to either pristine or protein-corona-coated MNPs, the collective shifts in color across all dyes create a unique molecular fingerprint for each type of MNP. This method demonstrates high sensitivity, capable of detecting MNPs of various sizes (50 nm, 100 nm, and 2 μm) and differentiating them from controls at concentrations as low as 10 ng/mL using standard chemometric techniques, ensuring accurate results without error. Additionally, the method can effectively distinguish between pristine and protein-corona-coated polystyrene MNPs. This colorimetric approach offers a rapid, cost-effective, and accurate method for monitoring MNP pollution and assessing their prior interactions with biological systems.

Are mixtures of micro/nanoplastics more toxic than individual micro or nanoplastic contamination in the clam Ruditapes decussatus?

The abundance of micro (MPs) and nano (NPs) sized plastic particles in the ocean is concerning due to their harmful effects on marine life. The interactions between MPs and NPs in the marine environment and their impact on marine biota remain not fully understood. This study contributes with new insights into the interaction between polystyrene NPs (PSNPs) and polyethylene MPs (PEMPs) on the clam Ruditapes decussatus. Results showed ingestion of MPs and NPs by clams, with PSNPs demonstrating higher toxicity in hemolymph. While no genotoxicity was observed, clams treated with MPs and the mixture showed increased acetylcolinesterase (AchE) activity over time. Additionally, the antioxidant defense system mitigated oxidative stress, suggesting effective neutralization of reactive oxygen species. Hazard assessment indicated the greatest impact on clam digestive glands after ten days of exposure, with an antagonistic interaction between MPs and NPs noted.

The size-dependent effects of nanoplastics in mouse primary hepatocytes from cells to molecules

Nanoplastics (NPs) are easily ingested by organisms and their major accumulation organ was determined to be liver. To date, the size-dependent cytotoxicity of NPs on mammalian hepatocytes remains unclear. This study utilized mouse primary hepatocytes and catalase (CAT) as specific receptors to investigate the toxicity of NPs from cells to molecules, focusing on size-dependent effects. Results showed that the larger the particle size of NP at low doses (≤50 mg/L), the most pronounced inhibitory effect on hepatocyte viability. 20 nm NPs significantly inhibit cell viability only at high doses (100 mg/L). Larger NP particles (500 nm and 1000 nm) resulted in a massive release of lactate dehydrogenase (LDH) from the cell (cell membrane damage). Reactive oxygen species (ROS), superoxide dismutase (SOD) and CAT tests suggest that NPs disturbed the cellular antioxidant system. 20 nm NPs show great strength in oxidizing lipids and disrupting mitochondrial function compared to NPs of other particle sizes. The degree of inhibition of CAT activity by different sized NPs was coherent at the cellular and molecular levels, and NP-500 had the most impact. This suggests that the structure and microenvironment of the polypeptide chain in the vicinity of the CAT active site is more susceptible to proximity and alteration by NP-500. In addition, the smaller NPs are capable of inducing relaxation of CAT backbone, disruption of H-bonding and reduction of α-helix content, whereas the larger NPs cause contraction of CAT backbone and increase in α-helix content. All NPs induce CAT fluorescence sensitization and make the chromophore microenvironment hydrophobic. This study provides new insights for NP risk assessment and applications.

Effects of polystyrene nanoplastic size on zebrafish embryo development

Polystyrene nanoplastics (PS) require a comprehensive evaluation of their toxicity and potential risks to humans and the environment. The zebrafish model, a well-established animal model increasingly utilized for nanotoxicity assessments, was employed in this study. Our research aimed to explore the toxic effects of PS with sizes of 30, 100, 200, and 450 nm on zebrafish embryos. Exposure experiments were conducted on embryos at 4 h post-fertilization (hpf) using various concentrations of nanoparticles (20, 40, 60, 80, and 100 mg/L) until 96 hpf. Notably, PS ranging from 100 to 450 nm did not adversely affect zebrafish embryo development. However, PS with a size of 30 nm at a concentration of 100 mg/L resulted in embryo mortality but not embryonic malformations. Furthermore, our investigation confirmed the uptake of these nanoparticles by zebrafish larvae following the opening of their mouths, with the particles being found predominantly in the digestive system of the larvae. Additionally, 30 nm PS were found to significantly modulate the expression levels of genes associated with oxidative stress and apoptosis. These findings highlight the developmental impacts of 30 nm PS on zebrafish embryos, raising concerns about potential similar consequences in humans. Considering our findings, it is essential to encourage further research into the management and regulation of PS to mitigate their potential environmental and health impacts.

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

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

Innovative application of Nile Red (NR)-based dye for direct detection of micro and nanoplastics (MNPs) in diverse aquatic environments

This paper presents the results of a research aimed at establishing a novel method for the detection of primary and secondary micro- and nanoplastics (MNPs), by using the fluorescence properties of the dye Nile Red-n-heptane (NR-H). The method has been applied to the detection of laboratory degraded polymers (Polystyrene, PS and Polyethylene Terephthalate, PET) as well as traceable latex microspheres in aqueous environments, showing a remarkable detection capacity and avoiding the prior extraction or processing of MNPs in natural samples, with significant time savings compared to conventional methods. The study has been carried out on various types of water, including samples from wastewater treatment plants, boreholes, seawater and synthesized seawater. The effectiveness of the staining process was evaluated by scanning electron microscopy (SEM), dynamic light scattering (DLS) and optical microscopy. As a result, a novel standardizable protocol for the rapid detection of MNPs has been established, with the potential to improve environmental protection through fast in-situ detection and identification of plastic contaminants. The limitations of the protocol in the quantification of MNPs have also been identified and further studies are proposed to overcome these limitations.

Polystyrene nanoplastics as an ecotoxicological hazard: cellular and transcriptomic evidences on marine and freshwater in vitro teleost models

The contamination of marine and freshwater environments by nanoplastics is considered a global threat for aquatic biota. Taking into account the most recent concentration range estimates reported globally and recognizing a knowledge gap in polystyrene nanoplastics (PS-NPs) ecotoxicology, the present work investigated the harmful effects of 20 nm and 80 nm PS-NPs, at increasing biological complexity, on the rainbow trout Oncorhynchus mykiss RTG-2 and gilthead seabream Sparus aurata SAF-1 cell lines. Twenty nm PS-NPs exerted a greater cytotoxicity than 80 nm ones and SAF-1 were approximately 4-fold more vulnerable to PS-NPs than RTG-2. The engagement of PS-NPs with plasma membranes was accompanied by discernible uptake patterns and morphological alterations along with a nuclear translocation already within a 30-min exposure. Cells were structurally damaged only by the 20 nm PS-NPs in a time-dependent manner as indicated by distinctive features of the execution phase of the apoptotic cell death mechanism such as cell shrinkage, plasma membrane blebbing, translocation of phosphatidylserine to the outer leaflet of the cell membrane and DNA fragmentation. At last, functional analyses unveiled marked transcriptional impairment at both sublethal and lethal doses of 20 nm PS-NPs, with the latter impacting the "Steroid biosynthesis", "TGF-beta signaling pathway", "ECM-receptor interaction", "Focal adhesion", "Regulation of actin cytoskeleton" and "Protein processing in endoplasmic reticulum" pathways. Overall, a distinct ecotoxicological hazard of PS-NPs at environmentally relevant concentrations was thoroughly characterized on two piscine cell lines. The effects were demonstrated to depend on size, exposure time and model, emphasizing the need for a comparative evaluation of endpoints between freshwater and marine ecosystems.

From tissue lesions to neurotoxicity: The devastating effects of small-sized nanoplastics on red drum Sciaenops ocellatus

Nanoplastic pollution typically exhibits more biotoxicity to marine organisms than microplastic pollution. Limited research exists on the toxic effects of small-sized nanoplastics on marine fish, especially regarding their post-exposure resilience. In this study, red drum (Sciaenops ocellatus) were exposed to small-sized polystyrene nanoplastics (30 nm, PS-NPs) for 7 days for the exposure experiments, followed by 14 days of recovery experiments. Histologically, hepatic lipid droplets and branchial epithelial liftings were the primary lesions induced by PS-NPs during both exposure and recovery periods. The inhibition of total superoxide dismutase activity and the accumulation of malondialdehyde content throughout the exposure and recovery periods. Transcriptional and metabolic regulation revealed that PS-NPs induced lipid metabolism disorders and DNA damage during the initial 1-2 days of exposure periods, followed by immune responses and neurotoxicity in the later stages (4-7 days). During the early recovery stages (2-7 days), lipid metabolism and cell cycle were activated, while in the later recovery stage (14 days), the emphasis shifted to lipid metabolism and energy metabolism. Persistent histological lesions, changes in antioxidant capacity, and fluctuations in gene and metabolite expression were observed even after 14 days of recovery periods, highlighting the severe biotoxicity of small-sized PS-NPs to marine fish. In summary, small-sized PS-NPs have severe biotoxicity, causing tissue lesions, oxidative damage, lipid metabolism disorders, DNA damage, immune responses, and neurotoxicity in red drum. This study offers valuable insights into the toxic effects and resilience of small-sized nanoplastics on marine fish.

Ecological risk assessment of microplastics and mesoplastics in six common fishes from the Bay of Bengal Coast

Plastic particles have emerged as a growing threat to both ecosystems and human well-being, as they are being ingested and accumulate at different trophic levels. However, microplastic and mesoplastic contamination and its risk to coastal and marine water fish have not been well studied, particularly in the northern Bay of Bengal. In this study, the presence of small-scale plastic particles (micro- and meso-sized) in the gastrointestinal tract (GIT) and muscles of six edible fish species from the northern Bay of Bengal Coast were identified and analyzed. The overall range of microplastics was 1.74 ± 0.23-3.79 ± 2.03items/g in muscle and 0.54 ± 0.22-5.96 ± 3.16 items/g in the GIT, with 16.38 ± 8.08-31.88 ± 12.09 items/individual. No mesoplastics were found in muscle tissue, but they were present in the GIT at concentrations ranging from 0.33 ± 0.27 to 0.03 ± 0.02 items/g and from 0.51 ± 0.05to 1.38 ± 1.01 items/individual. Lepturacanthus savala accumulated the most microplastics in muscle, and Harpadon nehereus had the least. In addition, the highest levels of mesoplastics were detected in the GIT of Polynemus paradiseus and the lowest was detected in the GIT of Lutjenus sanguineus. Omnivorous fish showed higher plastic concentrations than carnivorous fish, which was linked to dietary habits, feeding strategies and digestive processes. Plastic material predominantly accumulated in the GIT rather than in the muscle. The majority of ingested plastic particles were fibres (95.18 %), were violet in color (34 %), and were < 0.5 mm in size (87 %). The dominant microplastic polymers included 38 % PE, 15 % PP, 33 % PU, and 14 % CES. In contrast, the prevalent mesoplastic polymers comprised 45 % PE, 19 % PP, 13 % PS, 16 % PA, and 7 % PET. Subsequently, a hazard analysis using the polymer hazard index (PHI) revealed that plastic contamination was of distinct hazard categories for different polymer types, ranging from grade I (<1) to grade IV (100-1000). The assessment of the contamination factor (1 < CF < 3) and pollution load index (PLI > 1) indicated moderate contamination of fish by the ingestion of plastic debris. This study provides the foremost evidence for the presence of mesoplastics and microplastics in coastal and marine fish in the study region, paving the way for future investigations and policy implementation.

Impact of aging of primary and secondary polystyrene nanoplastics on the transmission of antibiotic resistance genes in anaerobic digestion

Sewage sludge is a significant reservoir of nano/microplastics (NPs/MPs) and antibiotic resistance genes (ARGs). Research has revealed that NPs/MPs may exert an inhibitory effect on anaerobic digestion (AD) of sludge. Moreover, NPs/MPs can influence microbial community diversity and composition, potentially increasing ARGs dissemination. The morphological changes to NPs/MPs surface due to aging contribute to modifying hydrophobic properties. To date, there is limited comprehension regarding how various surface properties of NPs influence ARGs dissemination during AD. This study investigated the impact of primary aged/non-aged and secondary aged/non-aged polystyrene nanoplastics (PSNPs) on ARGs and mobile genetic elements (MGEs) propagation during AD. The findings indicated that the UV-aging process resulted in surface oxidation and distinct morphological characteristics in both primary and secondary PSNPs, while the surface oxidation effect was more pronounced in the secondary aged PSNPs. High concentrations (150 μg/L) of primary and secondary PSNPs inhibited methane production, with secondary PSNPs causing greater inhibition by 16 to 20 % compared to control. In contrast, low concentration (25 μg/L) had negligible or slightly positive effects on methane production. PSNPs at 150 μg/L reduced total VFA concentration, indicating an inhibitory effect on the fermentation step in the AD process. Primary and secondary PSNPs exhibited changes in EPS characteristics. ARGs abundance was enriched in reactors amended with PSNPs, with the highest abundance of 8.54 × 105 copies/g sludge observed in the secondary aged PSNPs (150 μg/L) reactor. Reactors exposed to aged PSNPs exhibited a relatively higher abundance of ARGs compared to reactors exposed to non-aged PSNPs. Exposure to PSNPs increased the microbial community diversity within the digesters and triggered the enrichment of Comamonadaceae and Syntrophaceae, belonging to Proteobacteria phylum. On the other hand, archaeal communities tended to shift towards hydrogenotrophic methanogens in PSNPs reactors. The correlation analysis showed that Comamonadaceae were positively correlated with the majority of ARGs and intl1. A positive correlation was observed between MGEs and most ARGs, suggesting that the increased proliferation of ARGs under PSNPs exposure may be linked to the abundance of MGEs, which in turn promotes the growth of hosts carrying ARGs. These findings suggest that aged and non-aged NPs could substantially impact the spread of ARGs and MGEs, which also led to notable alterations in the composition of the microbial community. Overall, this study provides valuable insights into the multifaceted impacts of PSNPs with various characteristics on AD processes, microbial communities, and ARGs proliferation, highlighting the urgent need for comprehensive assessments of NPs pollutants in the environment.

Toxicological review of micro- and nano-plastics in aquatic environments: Risks to ecosystems, food web dynamics and human health

The increase of micro- and nano-plastics (MNPs) in aquatic environments has become a significant concern due to their potential toxicological effects on ecosystems, food web dynamics, and human health. These plastic particles emerge from a range of sources, such as the breakdown of larger plastic waste, consumer products, and industrial outputs. This review provides a detailed report of the transmission and dangers of MNPs in aquatic ecosystems, environmental behavior, and interactions within aquatic food webs, emphasizing their toxic impact on marine life. It explores the relationship between particle size and toxicity, their distribution in different tissues, and the process of trophic transfer through the food web. MNPs, once consumed, can be found in various organs, including the digestive system, gills, and liver. Their consumption by lower trophic level organisms facilitates their progression up the food chain, potentially leading to bioaccumulation and biomagnification, thereby posing substantial risks to the health, reproduction, and behavior of aquatic species. This work also explores how MNPs, through their persistence and bioaccumulation, pose risks to aquatic biodiversity and disrupt trophic relationships. The review also addresses the implications of MNPs for human health, particularly through the consumption of contaminated seafood, highlighting the direct and indirect pathways through which humans are exposed to these pollutants. Furthermore, the review highlights the recommendations for future research directions, emphasizing the integration of ecological, toxicological, and human health studies to inform risk assessments and develop mitigation strategies to address the global challenge of plastic pollution in aquatic environments.

Environmental and Sublethal Concentrations of Polystyrene Nanoplastics Induced Antioxidant System, Transcriptomic Responses, and Disturbed Gut Microbiota in Oyster Magallana Hongkongensis

Nanoplastics (NPs) are emerging contaminants having persistent nature, diverse ecological impacts, and potential food safety risks. Here, we examined the ecotoxicity of 80 nm polystyrene nanoplastics (PS-NPs) at environmentally relevant concentrations (ERCs, 10 and 100 μg/L), and sublethal concentrations (SLCs, 500 and 2500 μg/L) in Magallana hongkongensis. Results showed that SLCs significantly (p < 0.05) increased superoxide dismutase (SOD), catalase (CAT), and alkaline phosphatase (AKP) activities and altered tnfα, cat, gst, sod, and se-gpx genetic expressions. Further, PS-NP exposure at both levels reduced beneficial bacteria and increased potentially pathogenic bacteria in the gut. In transcriptomic analysis, 5118 and 4180 differentially expressed genes (DEGs) were identified at ERCs, while 5665 and 4817 DEGs were found at SLCs, respectively. Upregulated DEGs enriched lysosomes, ABC transporters, and apoptosis pathways, while downregulated DEGs enriched ribosomal pathways. Overall, ERCs significantly altered gut microbiota and transcriptomic responses, while SLCs, in addition, also impacted the antioxidant and immune systems.

Presence of humic acid in the environment holds promise as a potential mitigating factor for the joint toxicity of polystyrene nanoplastics and herbicide atrazine to Chlorella vulgaris: 96-H acute toxicity

Increasing amounts of amino-functionalized polystyrene nanoplastics (PS-NH2) are entering aquatic ecosystems, raising concerns. Hence, this study investigated 96-h acute toxicity of PS-NH2 and its combination with the pesticide atrazine (ATZ) in the absence/presence of humic acid (HA) on the microalgae Chlorella vulgaris (C. vulgaris). Results showed that both PS-NH2 and PS-NH2+ATZ reduced algal growth, photosynthetic pigments, protein content, and antioxidant capacity, while increasing enzymatic activities. Gene expression related to oxidative stress was altered in C. vulgaris exposed to these treatments. Morphological and intracellular changes were also observed. The combined toxicity of PS-NH2+ATZ demonstrated a synergistic effect, but the addition of environmentally relevant concentration of HA significantly alleviated its toxicity to C. vulgaris, indicating an antagonistic effect due to the emergence of an eco-corona, and entrapment and sedimentation of PS-NH2+ATZ particles by HA. This study firstly highlights the role of HA in mitigating the toxicity of PS-NH2 when combined with other harmful compounds, enhancing our understanding of HA's presence in the environment.

Investigation of the effects of nanoplastic polyethylene terephthalate on environmental toxicology using model Drosophila melanogaster

Plastic pollution has become a major environmental concern, and various plastic polymers are used daily. A study was conducted to examine the toxic effects of polyethylene terephthalate (PET) nanoplastics (NPLs) on Drosophila melanogaster. We have successfully synthesized PET NPLs and characterized using DLS, Zeta potential, TEM, HRTEM, SAED, XRD, FTIR, and Raman spectroscopy to gain crucial insights into the structure and properties. We fed PET NPLs to Drosophila to assess toxicity. ROS was quantified using DCFH-DA and NBT, and the nuclear degradation was checked by DAPI staining. Quantification of protein and activity of antioxidant enzymes like SOD, catalase depicted the adverse consequences of PET NPLs exposure. The dorsal side of the abdomens, eyes, and wings were also defective when phenotypically analyzed. These results substantiate the genotoxic and cytotoxic impact of nanoplastics. Notably, behavioral observations encompassing larval crawling and climbing of adults exhibit normal patterns, excluding the presence of neurotoxicity. Adult Drosophila showed decreased survivability, and fat accumulation enhanced body weight. These findings contribute to unraveling the intricate mechanisms underlying nanoplastic toxicity and emphasize its potential repercussions for organismal health and ecological equilibrium.

Microplastic contamination in Ashtamudi Lake, India: Insights from a Ramsar wetland

Estuaries function as temporary storage sites for plastic debris, influencing the distribution of microplastics (MPs) across ecosystems. This research delves into the presence of MPs in the water, sediment, fish, and shellfish of Ashtamudi Lake, a Ramsar wetland with brackish water located on the southwest coast of India. Given the lake's significance in supporting the livelihoods of numerous fishers and acting as a vital source of fishery resources for both local consumption and export, examining the contamination of the system by MPs becomes particularly pertinent. The highest percentage composition of MPs was found in macrofauna at 60.6% (with fish at 19.6% and shellfish at 40.9%), followed by sediment (22.8%) and water (16.7%). The primary types of MPs identified in all samples were fibers (35.6%), fragments (33.3%), and films (28%), with beads being the least represented at 3.03%. ATR-FTIR and Raman spectra analysis identified five polymers from shellfish (polypropylene, polyethylene, polystyrene, nylon, and polyvinyl chloride), five from fish guts (nylon, polypropylene, polyethylene, polyurethane, and polysiloxane), four in sediment (polypropylene, polyethylene, nylon, rayon), and four in water samples (polypropylene, polyethylene, nylon, and polystyrene). SEM-EDAX analysis of MPs obtained from the samples revealed degradation and the presence of inorganic elements such as Na, Mg, Al, Si, S, K, Cl, P, and Ca, as well as heavy metals like Pb, Mo, Rh, Pd, Ti, and Fe. The existence of these plastic polymers and heavy metals in microplastic samples poses a threat to vulnerable biota; people consume contaminated fish and shellfish, underscoring the importance of monitoring MPs in lake water. This investigation of MPs in Ashtamudi Lake highlights the system's susceptibility to plastic pollution and the bioavailability of smaller MPs to aquatic organisms. Identified sources of MPs in the lake include fishing and aquaculture activities, sewage pollution, improper solid waste management in lake watersheds, and unsustainable tourism. Upstream and downstream management interventions are recommended to address MP pollution in Ashtamudi Lake.

Toxicity mechanisms of plastic nanoparticles in three terrestrial species: antioxidant system imbalance and neurotoxicity

The detrimental impacts of plastic nanoparticles (PNPs) are a worldwide concern, although knowledge is still limited, in particular for soil mesofauna. This study investigates the biochemical impact of 44 nm polystyrene PNPs on three soil models-Enchytraeus crypticus (Oligochaeta), Folsomia candida (Collembola) and Porcellionides pruinosus (Isopoda). Exposure durations of 3, 7 and 14 days (d) were implemented at two concentrations (1.5 and 300 mg kg-1 PNPs). Results revealed PNPs impact on the activities of the glutathione-dependent antioxidative enzyme, glutathione S-transferase (GST) and on the neurotransmitter acetylcholinesterase (AChE) for all three species. Catalase (CAT) played a minor role, primarily evident in F. candida at 300 mg kg-1 PNPs (CAT and GST response after 14 d), with no lipid peroxidation (LPO) increase. Even with the antioxidant defence, P. pruinosus was the most sensitive species for lipid oxidative damage (LPO levels increased after 7 d exposure to 300 mg kg-1 PNPs). Significant AChE inhibitions were measured already after 3 d to both PNP concentrations in F. candida and E. crypticus, respectively. Significant AChE inhibitions were also found in P. pruinosus but later (7 d). Overall, the toxicity mechanisms of PNPs involved antioxidant imbalance, being (mostly) the glutathione-associated metabolism part of that defence system. Neurotoxicity, linked to AChE activities, was evident across all species. Sensitivity to PNPs varied: P. pruinosus > F. candida ≅ E. crypticus. This pioneering study on PNPs toxicity in soil invertebrates underscores its environmental relevance, shedding light on altered biochemical responses, that may compromise ecological roles and soil ecosystem fitness.

Micro(nano)-plastics exposure induced programmed cell death and corresponding influence factors

Plastic products have played an indispensable role in our daily lives for several decades, primarily due to their cost-effectiveness and unmatched convenience. Nevertheless, recent developments in nanotechnology have propelled our attention toward a distinct category of plastic fine particulates known as micro(nano)-plastics (MPs/NPs). The investigation of the cytotoxic effects of MPs/NPs has emerged as a central and burgeoning area of research in environmental toxicology and cell biology. In the scope of this comprehensive review, we have meticulously synthesized recent scientific inquiries to delve into the intricate interplay between MPs/NPs and programmed cell death mechanisms, which encompass a range of highly regulated processes. First, the signaling pathways and molecular mechanisms of different programmed death modalities induced by MPs/NPs were elaborated, including apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. The causes of different programmed deaths induced by MPs/NPs, such as size, surface potential, functional group modification, aging, biological crown, and co-exposure of MPs/NPs are further analyzed. In contrast, the various cellular programmed death modes induced by MPs/NPs are not alone most of the time, and lastly, the connections between different cellular programmed death modes induced by MPs/NPs, such as interconversion, mutual promotion, and mutual inhibition, are explained. Our primary objective is to unveil the multifaceted toxicological implications of MPs/NPs on the intricate web of cellular fate and biological homeostasis. This endeavor not only broadens our understanding of the potential risks associated with MPs/NPs exposure but also underscores the urgent need for comprehensive risk assessments and regulatory measures in the context of environmental health.

An overview on dispersion procedures and testing methods for the ecotoxicity testing of nanomaterials in the marine environment

Considerable efforts have been devoted to develop or adapt existing guidelines and protocols, to obtain robust and reproducible results from (eco)toxicological assays on engineered nanomaterials (NMs). However, while many studies investigated adverse effects of NMs on freshwater species, less attention was posed to the marine environment, a major sink for these contaminants. This review discusses the procedures used to assess the ecotoxicity of NMs in the marine environment, focusing on the use of protocols and methods for preparing NMs dispersions and on the NMs physicochemical characterization in exposure media. To this purpose, a critical analysis of the literature since 2010 was carried out, based on the publication of the first NMs dispersion protocols. Among the 89 selected studies, only <5 % followed a standardized dispersion protocol combined with NMs characterization in ecotoxicological media, while more than half used a non-standardized dispersion method but performed NMs characterization. In the remaining studies, only partial or no information on dispersion procedures or on physicochemical characterization was provided. This literature review also highlighted that metal oxides NMs were the most studied (42 %), but with an increasing interest in last years towards nanoplastics (14 %) and multicomponent nanomaterials (MCNMs, 7 %), in line with the growing attention on these emerging contaminants. For all these NMs, primary producers as algae and bacteria were the most studied groups of marine species, in addition to mollusca, while organisms at higher trophic levels were less represented, likely due to challenges in evaluating adverse effects on more complex organisms. Thus, despite the wide use of NMs in different applications, standard dispersion protocols are not often used for ecotoxicity testing with marine species. However, the efforts to characterize NMs in ecotoxicological media recognize the importance of following conditions that are as standardized as possible to support the ecological hazard assessment of NMs.

The possible impacts of nano and microplastics on human health: lessons from experimental models across multiple organs

The widespread production and use of plastics have resulted in accumulation of plastic debris in the environment, gradually breaking down into smaller particles over time. Nano-plastics (NPs) and microplastics (MPs), defined as particles smaller than 100 nanometers and 5 millimeters, respectively, raise concerns due to their ability to enter the human body through various pathways including ingestion, inhalation, and skin contact. Various investigators demonstrated that these particles may produce physical and chemical damage to human cells, tissues, and organs, disrupting cellular processes, triggering inflammation and oxidative stress, and impacting hormone and neurotransmitter balance. In addition, micro- and nano-plastics (MNPLs) may carry toxic chemicals and pathogens, exacerbating adverse effects on human health. The magnitude and nature of these effects are not yet fully understood, requiring further research for a comprehensive risk assessment. Nevertheless, evidence available suggests that accumulation of these particles in the environment and potential human uptake are causes for concern. Urgent measures to reduce plastic pollution and limit human exposure to MNPLs are necessary to safeguard human health and the environment. In this review, current knowledge regarding the influence of MNPLs on human health is summarized, including toxicity mechanisms, exposure pathways, and health outcomes across multiple organs. The critical need for additional research is also emphasized to comprehensively assess potential risks posed by degradation of MNPLs on human health and inform strategies for addressing this emerging environmental health challenge. Finally, new research directions are proposed including evaluation of gene regulation associated with MNPLs exposure.

Tracking the micro- and nanoplastics in the terrestrial-freshwater food webs. Bivalves as sentinel species

Micro- (MPs) and nanoplastics (NPs) are currently ubiquitous in the ecosystems, and freshwater biota is still insufficiently studied to understand the global fate, transport paths, and consequences of their presence. Thus, in this study, we investigated the role of bivalves and a trophic transfer of MPs and NPs in an experimental food chain. The food chain consisted of terrestrial non-selective detritivore Dendrobaena (Eisenia) sp., freshwater benthic filter feeder Unio tumidus, and freshwater benthic detritivore-collectors Asellus aquaticus or Gammarus sp. Animals were exposed to different fluorescently labeled micro- and nanoplastics (PMMA 20 μm, nanoPS 15-18 nm, and 100 nm, PS 1 μm and 20 μm, PE from cosmetics) as well as to the faeces of animals exposed to plastics to assess their influence on the environmental transportation, availability to biota, and bioaccumulation of supplied particles. Damaged and intact fluorescent particles were observed in the faeces of terrestrial detritivores and in the droppings of aquatic filter feeders, respectively. They were also present in the guts of bivalves and of crustaceans which were fed with bivalve droppings. Bivalves (Unio tumidus, and additionally Unio pictorum, and Sphaerium corneum) produced droppings containing micro- and nanoparticles filtered from suspension and deposited them onto the tank bottom, making them available for broader feeding guilds of animals (e.g. collectors, like crustaceans). Finally, the natural ageing of PS and its morphological changes, leakage of the fluorescent labelling, and agglomeration of particles were demonstrated. That supports our hypothesis of the crucial role of the characterization of physical and chemical materials in adequately understanding the mechanisms of their interaction with biota. Microscopical methods (confocal, fluorescent, scanning electron) and Raman and FT-IR spectroscopy were used to track the particles' passage in a food web and monitor structural changes of the MPs' and NPs' surface.

Co-exposure to polystyrene nanoplastics and triclosan induces synergistic cytotoxicity in human KGN granulosa cells by promoting reactive oxygen species accumulation

In recent years, nanoplastics (NPs) and triclosan (TCS, a pharmaceutical and personal care product) have emerged as environmental pollution issues, and their combined presence has raised widespread concern regarding potential risks to organisms. However, the combined toxicity and mechanisms of NPs and TCS remain unclear. In this study, we investigated the toxic effects of polystyrene NPs and TCS and their mechanisms on KGN cells, a human ovarian granulosa cell line. We exposed KGN cells to NPs (150 μg/mL) and TCS (15 μM) alone or together for 24 hours. Co-exposure significantly reduced cell viability. Compared with exposure to NPs or TCS alone, co-exposure increased reactive oxygen species (ROS) production. Interestingly, co-exposure to NPs and TCS produced synergistic effects. We examined the activity of superoxide dismutase (SOD) and catalase (CAT), two antioxidant enzymes; it was significantly decreased after co-exposure. We also noted an increase in the lipid oxidation product malondialdehyde (MDA) after co-exposure. Furthermore, co-exposure to NPs and TCS had a more detrimental effect on mitochondrial function than the individual treatments. Co-exposure activated the NRF2-KEAP1-HO-1 antioxidant stress pathway. Surprisingly, the expression of SESTRIN2, an antioxidant protein, was inhibited by co-exposure treatments. Co-exposure to NPs and TCS significantly increased the autophagy-related proteins LC3B-II and LC3B-Ⅰ and decreased P62. Moreover, co-exposure enhanced CASPASE-3 expression and inhibited the BCL-2/BAX ratio. In summary, our study revealed the synergistic toxic effects of NPs and TCS in vitro exposure. Our findings provide insight into the toxic mechanisms associated with co-exposure to NPs and TCS to KGN cells by inducing oxidative stress, activations of the NRF2-KEAP1-HO-1 pathway, autophagy, and apoptosis.

Beneath the water column: Uncovering microplastic pollution in the sublittoral coastal sediments of the Canary Islands, Spain

Marine ecosystems pollution by microplastics (MPs) is a global problem of special concern. The present study examines the prevalence and distribution of MPs and cellulosic particles in sublittoral coastal sediments of the Canary Islands archipelago (Spain). At twenty-six different locations alongside seven islands, three samples were taken parallel to the shoreline between 1 and 10 m depth (n = 78). Sediment samples were primarily digested with a H2O2 solution followed by four flotations in a saturated NaCl solution. The mean concentration obtained was 3.9 ± 1.6 items/g of dry weight. A similar distribution pattern was observed across all islands concerning particles morphology, color, size and composition: mainly colorless/translucent and blue fibers (60.0%). Additionally, fragments were also found, and to a much lesser extent microbeads, films and tangled messes. MicroFourier Transform Infrared spectroscopy analysis of 12.5% of the fibers, showed that they were mainly cellulosic (54.5%) -either natural or semisynthetic- followed by polyester (22.7%) and acrylic (4.5%). The potential correlation between particle distribution in nearshore sediments and wave intensity was also explored. This work provides the first comprehensive report on the current MPs content of the seabed of the region.

The size-dependence and reversibility of polystyrene nanoplastics-induced lipid accumulation in mice: Possible roles of lysosomes

Nanoplastics (NPs) continue to accumulate in global aquatic and terrestrial systems, posing a potential threat to human health through the food chain and/or other pathways. Both in vivo and in vitro studies have confirmed that the liver is one of the main organs targeted for the accumulation of NPs in living organisms. However, whether exposure to NPs induces size-dependent disorders of liver lipid metabolism remains controversial, and the reversibility of NPs-induced hepatotoxicity is largely unknown. In this study, the effects of long-term exposure to environmentally relevant doses of polystyrene nanoplastics (PS-NPs) on lipid accumulation were investigated in terms of autophagy and lysosomal mechanisms. The findings indicated that hepatic lipid accumulation was more pronounced in mice exposed to 100 nm PS-NPs compared to 500 nm PS-NPs. This effect was effectively alleviated after 50 days of self-recovery for 100 nm and 500 nm PS-NPs exposure. Mechanistically, although PS-NPs exposure activated autophagosome formation through ERK (mitogen-activated protein kinase 1)/mTOR (mechanistic target of rapamycin kinase) signaling pathway, the inhibition of Rab7 (RAB7, member RAS oncogene family), CTSB (cathepsin B), and CTSD (cathepsin D) expression impaired lysosomal function, thereby blocking autophagic flux and contributing to hepatic lipid accumulation. After termination of PS-NPs exposure, lysosomal exocytosis was responsible for the clearance of PS-NPs accumulated in lysosomes. Furthermore, impaired lysosomal function and autophagic flux inhibition were effectively alleviated. This might be the main reason for the alleviation of PS-NPs-induced lipid accumulation after recovery. Collectively, we demonstrate for the first time that lysosomes play a dual role in the persistence and reversibility of hepatotoxicity induced by environmental relevant doses of NPs, which provide novel evidence for the prevention and intervention of liver injury associated with nanoplastics exposure.

Exposure to polystyrene nanoplastics induced physiological and behavioral effects on the brittle star Ophiactis virens

Nanoplastic contamination has become an issue of environmental concern but the information on the potential adverse effects of nanoplastics on marine ecosystems is still limited. Therefore, the aim of this work was to investigate the effects of the exposure to polystyrene nanoplastics (PS-NPs; 0.05, 0.5 and 5 μg/mL) on the brittles star Ophiactis virens. Diverse endpoints at different levels of biological organization were considered, including behavior, arm regeneration capacity and oxidative stress. PS-NPs were observed on the brittle star body surface but not in inner tissues. Accumulation of PS-NPs was observed in the pre-buccal cavity of animals exposed to 5 μg/mL PS-NPs which also displayed delayed righting activity and an oxidative stress condition. Nevertheless, no effect was observed on arm regeneration efficiency at any tested PS-NPs concentration. Overall, our results highlighted that prolonged exposure to high amounts of PS-NPs could interfere at least partially with the physiology of O. virens.

Emerging isolation and degradation technology of microplastics and nanoplastics in the environment

Microplastics (MPs, less than 5 mm in size) are widely distributed in surroundings in various forms and ways, and threaten ecosystems security and human health. Its environmental behavior as pollutants carrier and the after-effects exposed to MPs has been extensively exploited; whereas, current knowledge on technologies for the separation and degradation of MPs is relatively limited. It is essential to isolate MPs from surroundings and/or degrade to safe levels. This in-depth review details the origin and distribution of MPs. Provides a comprehensive summary of currently available MPs separation and degradation technologies, and discusses the mechanisms, challenges, and application prospects of these technologies. Comparison of the contribution of various separation methods to the separation of NPs and MPs. Furthermore, the latest research trends and direction in bio-degradation technology are outlooked.

Can "Risk-Sharing" Mechanisms Help Clonal Aquatic Plants Mitigate the Stress of Nanoplastics?

Most aquatic plants applied to ecological restoration have demonstrated a clonal growth pattern. The risk-spreading strategy plays a crucial role in facilitating clonal plant growth under external environmental stresses via clonal integration. However, the effects of different concentrations of nanoplastics (NPs) on the growth traits of clonal aquatic plants are not well understood. Therefore, this study aimed to investigate the impact of NPs exposure on seedlings of parent plants and connected offspring ramets. A dose response experiment (0.1, 1, and 10 mg L-1) showed that the growth of Eichhornia crassipes (water hyacinth) was affected by 100 nm polystyrene nanoplastics after 28 days of exposure. Tracer analysis revealed that NPs are accumulated by parent plants and transferred to offspring ramets through stolon. Quantification analysis showed that when the parent plant was exposed to 10 mg L-1 NPs alone for 28 days, the offspring ramets contained approximately 13 ± 2 μg/g NPs. In the case of connected offspring ramets, leaf and root biomass decreased by 24%-51% and 32%-51%, respectively, when exposed to NP concentrations ranging from 0.1 to 10 mg L-1. Excessive enrichment of NPs had a detrimental effect on the photosynthetic system, decreasing the chlorophyll content and nonphotochemical quenching. An imbalance in the antioxidant defense systems, which were unable to cope with the oxidative stress caused by NP concentrations, further damaged various organs. The root system can take up NPs and then transfer them to the offspring through the stolon. Interference effects of NPs were observed in terms of root activity, metabolism, biofilm composition, and the plant's ability to purify water. However, the risk-spreading strategy employed by parent plants (interconnected offspring ramets) offered some relief from NP-induced stress, as it increased their relative growth rate by 1 to 1.38 times compared to individual plants. These findings provide substantial evidence of the high NP enrichment capacity of E. crassipes for ecological remediation. Nevertheless, we must also remain aware of the environmental risk associated with the spread of NPs within the clonal system of E. crassipes, and contaminated cloned individuals need to be precisely removed in a timely manner to maintain normal functions.

Characterizing the Microplastic Content of Biosolids in Southern Ontario, Canada

The application of biosolids to agricultural land has been identified as a major pathway of microplastic (MP) pollution to the environment. Very little research, however, has been done on the MP content of biosolids within Canada. Fifteen biosolid samples from different treatment processes (liquid, dewatered, pelletized, and alkali-stabilized) were collected from 11 sources across southern Ontario to quantify and characterize the MP load within them. All samples exhibited MP concentrations ranging from 188 200 (±24 161) to 512 000 (±28 571) MPs/kg dry weight and from 4122 (±231) to 453 746 (±38 194) MPs/kg wet weight. Field amendment of these biosolids can introduce up to 3.73 × 106 to 4.12 × 108 MP/ha of agricultural soil. There was no significant difference in the MP concentrations of liquid, dewatered, and pelletized samples; but a reduction in MP content was observed in alkali-stabilized biosolids. Fragments composed 57.6% of the MPs identified, while 36.7% were fibers. In addition, MPs showed an exponential increase in abundance with decreasing size. Characterization of MPs confirmed that polyester was the most abundant, while polyethylene, polypropylene, polyamide, polyacrylamide, and polyurethane were present across the majority of biosolid samples. The results of the present study provide an estimate of the potential extent of MP contamination to agricultural fields through the amendment of biosolids. Environ Toxicol Chem 2024;00:1-14. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Micro and Nanoplastic Contamination and Its Effects on Freshwater Mussels Caged in an Urban Area

Plastic-based contamination has become a major cause of concern as it pervades many environments such as air, water, sediments, and soils. This study sought to examine the presence of microplastics (MPs) and nanoplastics (NPs) in freshwater mussels placed at rainfall/street runoff overflows, downstream (15 km) of the city centre of Montréal, and 8 km downstream of a municipal effluent dispersion plume. MPs and NPs were determined using flow cytometry and size exclusion chromatography using fluorescence detection. Following 3 months of exposure during the summer season, mussels contained elevated amounts of both MPs and NPs. The rainfall overflow and downstream of the city centre were the most contaminated sites. Lipid peroxidation, metallothioneins, and protein aggregates (amyloids) were significantly increased at the most contaminated sites and were significantly correlated with NPs in tissues. Based on the levels of MPs and NPs in mussels exposed to municipal effluent, wastewater treatment plants appear to mitigate plastic contamination albeit not completely. In conclusion, the data support the hypothesis that mussels placed in urbanized areas are more contaminated by plastics, which are associated with oxidative damage. The highest responses observed at the overflow site suggest that tire wear and/or asphalt (road) erosion MPs/NPs represent important sources of contamination for the aquatic biota.

Teratogenic effects of environmental concentration of plastic particles on freshwater organisms

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

Adaptive response of triploid Fujian oyster (Crassostrea angulata) to nanoplastic stress: Insights from physiological, metabolomic, and microbial community analyses

Triploid Fujian oyster (Crassostrea angulata) is crucial to aquaculture and coastal ecosystems because of its accelerated growth and heightened resilience against environmental stressors. In light of the increasing prevalence of nanoplastic pollution in the ocean, understanding its potential impact on this organism, particularly its adaptive responses, is of paramount importance. Despite this, the effects of nanoplastic pollution on the physiology of C. angulata remain largely unexplored. In this study, we explored the responses of triploid Fujian oysters to nanoplastic stress during a 14-day exposure period, employing an integrative methodology that included physiological, metabolomic, and 16S rRNA sequencing analyses. Our results demonstrate that the oysters exhibit a strong adaptive response to nanoplastic exposure, characterized by alterations in enzyme activity, metabolic pathways, and microbial community composition, indicative of an adaptive recovery state as opposed to a disordered state. Oysters subjected to elevated nanoplastic levels exhibited adaptive responses primarily by boosting the activity of the antioxidant enzyme catalase and elevating the levels of antioxidants such as adenosine, 3-(4-hydroxyphenyl)pyruvate, D-sorbitol, d-mannose, and unsaturated fatty acids, as well as the functional amino acids l-proline and l-lysine. Nanoplastic treatment also resulted in increased activity of succinate dehydrogenase, a key component of energy metabolism, and increased contents of intermediate metabolites or products of energy metabolism, such as adenosine monophosphate, adenosine, guanosine, creatine, and thiamine. Nanoplastic treatment led to an increase in the abundance of certain advantageous genera of gut bacteria, specifically Phaeobacter and Nautella. The observed adaptive response of triploid Fujian oysters to nanoplastic stress provides valuable insights into the mechanisms underpinning resilience in marine bivalves.

Chemical characterization of microplastic particles formed in airborne waste discharged from sewer pipe repairs

Microplastic particles are of increasing environmental concern due to the widespread uncontrolled degradation of various commercial products made of plastic and their associated waste disposal. Recently, common technology used to repair sewer pipes was reported as one of the emission sources of airborne microplastics in urban areas. This research presents results of the multi-modal comprehensive chemical characterization of the microplastic particles related to waste discharged in the pipe repair process and compares particle composition with the components of uncured resin and cured plastic composite used in the process. Analysis of these materials employs complementary use of surface-enhanced Raman spectroscopy, scanning transmission X-ray spectro-microscopy, single particle mass spectrometry, and direct analysis in real-time high-resolution mass spectrometry. It is shown that the composition of the relatively large (100 μm) microplastic particles resembles components of plastic material used in the process. In contrast, the composition of the smaller (micrometer and sub-micrometer) particles is significantly different, suggesting their formation from unintended polymerization of water-soluble components occurring in drying droplets of the air-discharged waste. In addition, resin material type influences the composition of released microplastic particles. Results are further discussed to guide the detection and advanced characterization of airborne microplastics in future field and laboratory studies pertaining to sewer pipe repair technology.

Surface modification significantly changed the effects of nano-polystyrene on sediment microbial communities and nitrogen metabolism

Nanoplastics are ubiquitous in the natural environment, and their ecological risks have received considerable attention. Surface modification is common for nanoplastics and an essential factor affecting their toxicity. However, studies on the potential effects of nanoplastics and their surface-modified forms on functional communities in aquatic systems are still scarce. This study investigated the effects of nano-polystyrene (nPS), amino-modified nPS (nPS-NH2), and carboxylated nPS (nPS-COOH) particles on sediment bacterial and fungal communities and their functions over a 60-day incubation period. The results showed that the fungal community was significantly inhibited by nPS-NH2 exposure, while the bacterial community diversity remained relatively stable in all nPS treatments. Proteobacteria and Ascomycota were the dominant phyla for the bacterial and fungal communities, respectively. Nitrification was inhibited in all nPS treatments, while denitrification was enhanced for nPS-NH2 and nPS-COOH treatments. The activity of four key denitrification enzymes (NAR, NIR, NOR, and NOS) was also significantly improved by nPS, resulting in increased nitrogen and nitrous oxide gas production, and decreased nitrate concentrations in the overlying water. This showed the total increased effect of nPS on the activity of denitrifiers. Our results suggest that surface modification significantly affects the effects of nPS on microbial communities and functions. The potential impacts of nPS on ecological functions should be elucidated with more attention.

The co-presence of polystyrene nanoplastics and ofloxacin demonstrates combined effects on the structure, assembly, and metabolic activities of marine microbial community

Nanoplastic is increasing in environments and can address toxic effects on various organisms. Particle size, concentration, and surface functionalization most influence nanoplastic toxicity. Besides, nanoplastic can adsorb other contaminants (e.g., antibiotics) to aggravate its adverse effects. The combined effects of nanoplastics and antibiotics on planktonic/benthic microbial communities, however, are still largely unknown. In this study, the combined effects of polystyrene nanoplastic and ofloxacin on the structure, assembly, and metabolic activities of marine microbial communities were investigated based on amplicon sequencing data. The results mainly demonstrate that: (1) nanoplastic and ofloxacin have greater impacts on prokaryotic communities than eukaryotic ones; (2) niche breadths of planktonic prokaryotes and benthic eukaryotes were shrank with both high nanoplastic and ofloxacin concentrations; (3) increased ofloxacin mainly reduces nodes/edges of co-occurrence networks, while nanoplastic centralizes network modularity; (4) increased nanoplastic under high ofloxacin concentration induces more differential prokaryotic pathways in planktonic communities, while benthic communities are less influenced. The present work indicates that co-presence of nanoplastics and ofloxacin has synergistic combined effects on community structure shifts, niche breadth shrinking, network simplifying, and differential prokaryotic pathways inducing in marine microbial communities, suggesting nanoplastics and its combined impacts with other pollutions should be paid with more concerns.

Cation-π mechanism promotes the adsorption of humic acid on polystyrene nanoplastics to differently affect their aggregation: Evidence from experimental characterization and DFT calculation

Multiple water-chemistry factors determine nanoplastics aggregation and thus change their bioavailability and ecological risks in natural aquatic environments. However, the dominant factors and their interactive mechanisms remain elusive. In this study, polystyrene nanoplastics (PSNPs) showed greater colloidal stability in Li Lake water compared to ultrapure water. The RDA and PARAFAC results suggested that dissolved organic carbon, humic acid (HA) in particular, Ca2+, and pH are critical factors influencing PSNPs aggregation. Batch experiments showed that the critical coagulation concentration (CCC) of PSNPs was increased with pH increase; HA increased the CCC of PSNPs in NaCl by 2.6-fold but decreased that in CaCl2 by 1.8-fold. Moreover, cations increased the adsorption of HA on PSNPs. The DFT results suggested that HA-cations complexes (EAE = -1.10 eV and -0.51 eV for HA-Ca2+ and HA-Na+, respectively) but not HA alone (EAE = -0.33 eV) are the main scenarios for their adsorption on PSNPs, and a cation-π mechanism between PSNPs and HA-cations complexes dominates PSNPs aggregation in this scenario. The findings are significant for better understanding the environmental process and fate of nanoplastics in aquatic environments. ENVIRONMENTAL IMPLICATION: Nanoplastics are kinds of emerging contaminants. Nanoplastic aggregation determines their bioavailability and toxic risks to ecological health. Herein, the hydrodynamic sizes of PSNPs in local Li Lake water was tested and a redundancy analysis was performed to examine the key water-chemistry factors driving PSNPs aggregation. Moreover, the mechanisms in PSNPs aggregation driven by multiple dominant water-chemistry factors including cations, pH, and DOC were firstly unveiled by combining experimental characterization and theoretical computations. This work improves our understanding of the environmental fate of nanoplastics and provides a theoretical basis for the risk assessment and control of nanoplastics in real aquatic environments.

Polystyrene nanoplastics in the marine mussel Mytilus galloprovincialis

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

Improvement of biodegradation of PET microplastics with whole-cell biocatalyst by interface activation reinforcement

Polyethylene terephthalate (PET) is an important basic polymer, which was used widely in variety of fields. Due to its high crystallinity, compact structure and strong surface hydrophobicity, PET has prominent resistance to biodegradation. In recent years, microplastics, especially polyethylene terephthalate (PET) microplastics, was considered as serious threaten to ecosystems. In this study, alkali-resistant bacteria were used as whole-cell catalysts to try to improve the biodegradation of PET microplastics by increasing the bio-interfacial activity of the polymer substrate. Surfactants were applicated to enhance interfacial activation of enzyme and PET interactions. And an integrated strategy was constructed based on alkali resistant bacteria to catalysis the hydrolysis of PET. The results showed that Tween 20 had the most obvious promoting effect among the four interfacial biocatalysts on biological-chemical combined hydrolysis of PET microplastics with whole-cell biocatalysts in alkaline environment. Obvious etching and fracture were observed on the PET fibre surface after biodegradation in presence of surfactant. The weight loss rate of PET substrate can reach 11.04% after 5 days of biodegradation. Thus, this research provides a promising method for efficient degradation of PET microplastics.

Combined toxic effects of nanoplastics and norfloxacin on mussel: Leveraging biochemical parameters and gut microbiota

Antibiotics and nanoplastics (NPs) are among the two most concerned and studied marine emerging contaminants in recent years. Given the large number of different types of antibiotics and NPs, there is a need to apply efficient tools to evaluate their combined toxic effects. Using the thick-shelled mussel (Mytilus coruscus) as a marine ecotoxicological model, we applied a battery of fast enzymatic activity assays and 16S rRNA sequencing to investigate the biochemical and gut microbial response of mussels exposed to antibiotic norfloxacin (NOR) and NPs (80 nm polystyrene beads) alone and in combination at environmentally relevant concentrations. After 15 days of exposure, NPs alone significantly inhibited superoxide dismutase (SOD) and amylase (AMS) activities, while catalase (CAT) was affected by both NOR and NPs. The changes in lysozyme (LZM) and lipase (LPS) were increased over time during the treatments. Co-exposure to NPs and NOR significantly affected glutathione (GSH) and trypsin (Typ), which might be explained by the increased bioavailable NOR carried by NPs. The richness and diversity of the gut microbiota of mussels were both decreased by exposures to NOR and NPs, and the top functions of gut microbiota that were affected by the exposures were predicted. The data fast generated by enzymatic test and 16S sequencing allowed further variance and correlation analysis to understand the plausible driving factors and toxicity mechanisms. Despite the toxic effects of only one type of antibiotics and NPs being evaluated, the validated assays on mussels are readily applicable to other antibiotics, NPs, and their mixture.

Silver nanoparticles and silver ions indistinguishably decrease sperm motility in Pacific oysters (Magallana gigas) after short-term direct exposure

The present study aimed to evaluate the reprotoxicity of environmental (0.25μg.L^-1) and supra-environmental (25μg.L^-1 and 250μg.L^-1) levels of silver nanoparticles (Ag NP) on the Pacific oyster (Magallana gigas), by determining sperm quality. For that, we evaluated sperm motility, mitochondrial function and oxidative stress. To determine whether the Ag toxicity was related to the NP or its dissociation into Ag ions (Ag⁺), we tested the same concentrations of Ag⁺. We observed no dose-dependent responses for Ag NP and Ag⁺, and both impaired sperm motility indistinctly without affecting mitochondrial function or inducing membrane damage. We hypothesize that the toxicity of Ag NP is mainly due to adhesion to the sperm membrane. Blockade of membrane ion channels may also be a mechanism by which Ag NP and Ag⁺ induce toxicity. The presence of Ag in the marine ecosystem is of environmental concern as it may affect reproduction in oysters.

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

Polymeric wastes are among the current major environmental problems due to potential pollution and contamination. Within the spectrum of polymeric waste, microplastics (MPs) and nanoplastics (NPs) have gained ground in recent research since these particles can affect the local biota, inducing toxic effects on several organisms. Different outcomes have been reported depending on particle sizes, shape, types, and exposed organisms and conditions, among other variables. This review aimed to compile and discuss the current knowledge and possible literature gaps regarding the MPs and NPs generation and their toxicological effects as stressors, considering polymer type (as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, or others), size (micro- or nano-scale), source (commercial, lab-synthesized, or environmental) and test organism group. In that sense, 615 publications were analyzed, among which 72 % discussed micro-sized plastics, while <28 % assayed the toxicity of NPs (<1 μm). For most polymers, MPs and NPs were commercially purchased and used without additional size reduction processes; except for polyethylene terephthalate studies that mostly used grinding and cutting methods to obtain MPs. Polystyrene (PS) was the main polymer studied, as both MPs and NPs. PS accounts for >90 % of NPs reports evaluated, reflecting a major literature gap if compared to its 35.3 % share on MPs studies. Among the main organisms, arthropods and fish combined accounted for nearly 40 % of toxicity testing. Overall, the different types of plastics showed a tendency to report toxic effects, except for the 'Survival/lethality' category, which might indicate that polymeric particles induce mostly sublethal toxic effects. Furthermore, despite differences in publication numbers, we observed greater toxicity reported for NPs than MPs with oxidative stress among the majorly investigated endpoints. This study allowed a hazard profile overview of micro/nanoplastics (MNPs) and the visualization of literature gaps, under a broad diversity of toxicological evidence.

The complexity of micro- and nanoplastic research in the genus Daphnia - A systematic review of study variability and a meta-analysis of immobilization rates

In recent years, the number of publications on nano- and microplastic particles (NMPs) effects on freshwater organisms has increased rapidly. Freshwater crustaceans of the genus Daphnia are widely used in ecotoxicological research as model organisms for assessing the impact of NMPs. However, the diversity of experimental designs in these studies makes conclusions about the general impact of NMPs on Daphnia challenging. To approach this, we systematically reviewed the literature on NMP effects on Daphnia and summarized the diversity of test organisms, experimental conditions, NMP properties and measured endpoints to identify gaps in our knowledge of NMP effects on Daphnia. We use a meta-analysis on mortality and immobilization rates extracted from the compiled literature to illustrate how NMP properties, study parameters and the biology of Daphnia can impact outcomes in toxicity bioassays. In addition, we investigate the extent to which the available data can be used to predict the toxicity of untested NMPs based on the extracted parameters. Based on our results, we argue that focusing on a more diverse set of NMP properties combined with a more detailed characterization of the particles in future studies will help to fill current research gaps, improve predictive models and allow the identification of NMP properties linked to toxicity.

Nanoplastic exposure inhibits feeding and delays regeneration in a freshwater planarian

The concentration of nanoplastics (NPs) is expected to increase in aquatic environments thus potentially threatening freshwater organisms through interactions with plastic particles that variously float, circulate in the water column or sink into the benthos. Studies into the mechanisms of any NP effects are still scarce, particularly with respect to the regenerative ability of biota for which there is no recognised model organism. The present study therefore aimed to investigate behavioural and regeneration responses of the freshwater planarian Girardia tigrina after 10 days exposed to along a gradient 0.01-10 mg/L of poly (styrene-co-methyl methacrylate) NPs (∼426 ± 175 nm). Exposure to NPs induced a significant reduction in planarian feeding rate even at low concentrations (LOEC of 0.01 mg/L), while head regeneration was delayed in a clear dose response way (LOEC of 0.1 mg/L for blastema length). Planaria locomotion assessed was not affected. Our results highlight the potential adverse effects of exposure to poly (styrene-co-methyl methacrylate) NPs and show that feeding behaviour and regeneration of a freshwater benthic organism can be indicators of the resulting toxicity. Planarians are becoming widely used model organisms in ecotoxicology and can help to address potential effects of plastic polymers on regeneration.

Assessing the potential for the introduction and spread of alien species with marine litter

The introduction and transport of marine invasive species into new environments are a great threat to biodiversity and ecosystem services with potential economic repercussions. There are several routes and mechanisms by which alien species are transported and dispersed in the marine environment (shipping, waterways, and aquaculture). Each year, millions of tons of plastic enter the ocean. The presence of floating marine litter in marine environments provides a substrate for marine organisms and may increase the potential for the transport of alien species. Research on the role of marine litter in the introduction of alien marine species has grown exponentially in recent years. In this study, studies examining the transport and dispersal of alien species by marine litter are reviewed. In this review, we identified 67 alien species associated with marine litter. The most recurrent alien phyla found on marine litter are Arthropoda (29 %), Mollusca (23 %), Bryozoa (19 %), Annelida (7 %) and Cnidaria (5 %). Plastic appears to be more efficient in transporting alien species than by natural means. Their characteristics (buoyancy and persistence) allow them to be widely dispersed throughout all ocean compartments. Thus, plastics may act as a primary vector, carrying organisms to remote areas but can also facilitate the secondary spread of alien species between points of invasion. Despite the growing number of studies on this subject, much work remains to be done to understand the roles of plastics in the introduction of alien species and to develop solutions to mitigate the issue.

Effects of polypropylene nanofibers on soft corals

Current information regarding the effects of both micro- and nano-plastic debris on coral reefs is limited; especially the toxicity onto corals from nano-plastics originating from secondary sources such as fibers from synthetic fabrics. Within this study, we exposed the alcyonacean coral Pinnigorgia flava to different concentrations of polypropylene secondary nanofibers (0.001, 0.1, 1.0 and 10 mg/L) and then assayed mortality, mucus production, polyps retraction, coral tissue bleaching, and swelling. The assay materials were obtained by artificially weathering non-woven fabrics retrieved from commercially available personal protective equipment. Specifically, polypropylene (PP) nanofibers displaying a hydrodynamic size of 114.7 ± 8.1 nm and a polydispersity index (PDI) of 0.431 were obtained after 180 h exposition in a UV light aging chamber (340 nm at 0.76 Wˑm^-2ˑnm^-1). After 72 h of PP exposure no mortality was observed but there were evident stress responses from the corals tested. Specifically, the application of nanofibers at different concentrations caused significant differences in mucus production, polyps retraction and coral tissue swelling (ANOVA, p < 0.001, p = 0.015 and p = 0.015, respectively). NOEC (No Observed Effect Concentration) and LOEC (Lowest Observed Effect concentration) at 72 h resulted 0.1 mg/L and 1 mg/L, respectively. Overall, the study indicates that PP secondary nanofibers can cause adverse effects on corals and could potentially act as a stress factor in coral reefs. The generality of the method of producing and assaying the toxicity of secondary nanofibers from synthetic textiles is also discussed.

Destabilization of polystyrene nanoplastics with different surface charge and particle size by Fe electrocoagulation

Nanoplastics (NPs) discharged from wastewater could pose a major threat to organisms in aquatic environments. Effective removal of NPs by the current conventional coagulation-sedimentation process is not yet satisfactory. This study aimed to investigate the destabilization mechanism of polystyrene NPs (PS-NPs) with different surface properties and sizes (i.e., 90 nm, 200 nm, and 500 nm) by Fe electrocoagulation (EC). Two types of PS-NPs were prepared by a nanoprecipitation method using sodium dodecyl sulfate and cetrimonium bromide solutions to produce negatively-charged SDS-NPs and positively-charged CTAB-NPs. For both NPs, obvious floc aggregation from 7 μm to 14 μm was observed only at pH 7 with particulate Fe accounted for >90 %. At pH 7, Fe EC removed 85.3 %, 82.8 %, and 74.7 % of the negatively-charged SDS-NPs at small-, mid-, and large-sizes from 90 nm, 200 nm, to 500 nm, respectively. Small-size SDS-NPs_{(90 nm)} were destabilized through physical adsorption on the surface of Fe flocs, while the main removal mechanism of mid- and large-SDS-NPs_{(200 nm and 500 nm)} involved the enmeshment of large Fe flocs. Compared to SDS-NPs_{(200 nm and 500 nm)}, Fe EC performed similar destabilization behavior to two CTAB-NPs_{(200 nm and 500 nm)}, but it resulted in much lower removal rates of 54.8 % - 77.9 %. The Fe EC also exhibited no removal (<1 %) ability toward the small-size and positively-charged CTAB-NPs_{(90 nm)} due to insufficient formation of effective Fe flocs. Our results provide insight into the destabilization of PS in nano-scale with different sizes and surface properties, which clarifies the behavior of complex NPs in a Fe EC-system.

Nanoplastics potentiate mercury toxicity in a marine copepod under multigenerational exposure

The continuous fragmentation of plastics and release of synthetic nanoplastics from products have been aggravating nanoplastic pollution in the marine ecosystem. The carrier role of nanoplastics may increase the bioavailability and toxicity effects of toxic metals, e.g., mercury (Hg), which is of growing concern. Here, the copepod Tigriopus japonicus was exposed to polystyrene nanoplastics (PS NPs) and Hg (alone or combined) at environmental realistic concentrations for three generations (F0-F2). Then, Hg accumulation, physiological endpoints, and transcriptome were analyzed. The results showed that the copepod's reproduction was significantly inhibited under PS NPs or Hg exposure. The presence of PS NPs caused significantly higher Hg accumulation, lower survival, and lower offspring production in copepods relative to Hg exposure, suggesting an increased threat to the copepod's survivorship and health. From the molecular perspective, combined PS NPs and Hg caused a graver effect on the DNA replication, cell cycle, and reproduction pathways relative to Hg exposure, linking to lower levels of survivorship and reproduction. Taken together, this study provides an early warning of nanoplastic pollution for the marine ecosystem not only because of their adverse effect per se but also their carrier role for increasing Hg bioaccumulation and toxicity in copepods.

Acute effects of polystyrene nanoplastics on the immune response in Sepia esculenta larvae

With extensive use of plastic products, microplastics (MPs, < 5 mm) and nanoplastics (NPs, < 1 μm) have become major pollutants in ecosystem, especially in marine environment. In recent years, researches on the impact of NPs on organisms have gradually increased. However, studies on the influence of NPs on cephalopods are still limited. Golden cuttlefish (Sepia esculenta), an important economic cephalopod, is a shallow marine benthic organism. In this study, the effect of acute exposure (4 h) to 50-nm polystyrene nanoplastics (PS-NPs, 100 μg/L) on the immune response of S. esculenta larvae was analyzed via transcriptome data. A total of 1260 DEGs were obtained in the gene expression analysis. The analyses of GO, KEGG signaling pathway enrichment, and protein-protein interaction (PPI) network were then performed to explore the potential molecular mechanisms of the immune response. Finally, 16 key immune-related DEGs were obtained according to the number of KEGG signaling pathways involved and the PPI number. This study not only confirmed that NPs had an impact on cephalopod immune response, but also provided novel insights for further unmasking the toxicological mechanisms of NPs.

Nanoplastics affect the growth of sea urchins (Strongylocentrotus intermedius) and damage gut health

Nanoplastics (NPs) are abundant and widespread throughout the ocean, not only causing severe environmental pollution, but also worsening the aquatic organisms. To elucidate the mechanism of biological toxic effects underlying the responses of marine invertebrates to NPs, Strongylocentrotus intermedius was stressed with three different NPs concentrations (0 particles/L, 10² particles/L and 10⁴ particles/L). Specific growth rates, enzyme activity, gut tissue section observation and structural characteristics of the gut bacterial community were analyzed. After 28 days of exposure, the specific growth rate of S. intermedius decreased significantly with NPs groups. Further, both lysozyme, pepsin, lipase and amylase activities decreased, while the superoxide dismutase activity increased, indicating that NPs negatively affected digestive enzyme and immune enzyme activity. The analysis of gut tissue sections revealed that NPs caused atrophy and cytoplasmic reduction in the epithelial cells of the S. intermedius intestine. Moreover, the structural characterization of the gut bacterial community indicated significant changes in the abundances of members from Campylobacterota, Chlamydiae, and Firmicutes. Members from Arcobacteraceae, Christensenellaceae and Clostridia were endemic to the NPs treatment. The KEGG database analysis demonstrated that the metabolic pathways specific to the NPs treatment group were significantly associated with growth, energy metabolism, and immunity. In summary, NPs have negatively affected on physiological response and altered gut microecological environment.

Polystyrene nanoplastics differentially influence the outcome of infection by two microparasites of the host Daphnia magna

The accumulation of micro- and nanoplastic particles in freshwater bodies has given rise to much concern regarding their potential adverse effects on aquatic biota. Beyond their known effects on single species, recent experimental evidence suggests that host-parasite interactions can also be affected by environmental concentrations of micro- and nanoplastics. However, investigating the effects of contaminants in simplified infection settings (i.e. one host, one parasite) may understate their ecological relevance, considering that co-infections are common in nature. We exposed the cladoceran Daphnia magna to a fungal parasite of the haemolymph (Metschnikowia bicuspidata) and a gut microsporidium (Ordospora colligata), either in single or co-infection. In addition, Daphnia were raised individually in culture media containing 0, 5 or 50 mg l^-1 of polystyrene nanoplastic beads (100 nm). Only few infections were successful at the higher nanoplastic concentration, due to increased mortality of the host. While no significant effect of the low concentration was detected on the microsporidium, the proportion of hosts infected by the fungal parasite increased dramatically, leading to more frequent co-infections under nanoplastic exposure. These results indicate that nanoplastics can affect the performance of distinct pathogens in diverging ways, with the potential to favour parasite coexistence in a common zooplanktonic host. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.