Microplastic in marine organism: Environmental and toxicological effects

Influence of paternal factors on plastic ingestion and brominated chemical exposure in East Tropical Atlantic Procellariid chicks

The presence of plastic debris and organo-brominated compounds in the marine environment poses a concern to wildlife. Plastic can absorb and release chemical compounds, making their ingestion potentially harmful, while chemical compounds have become omnipresent, with a tendency to bioaccumulate in the food web. Seabirds are often used as indicators of marine plastic pollution, yet studies on the exposure of tropical communities to plastic contamination are still scarce. In this study we monitored the amounts of plastics in faeces and organo-brominated compounds ingested/assimilated in feathers by adults and chicks of Cape Verde shearwaters and Bulwer's petrels from Cabo Verde. Anthropogenic pollutants, polybrominated diphenyl ethers (PBDEs), and naturally generated methoxylated-PBDEs (MeO-PBDEs) were among the probed compounds. The frequency of plastic debris ingestion was similar in both species' adults and chicks, although, the characteristics of the ingested plastic differed. Frequency and number of microplastics increased throughout the nestling season for chicks from both species. All species and age groups showed the presence of PBDEs and MeO-PBDEs. Among PBDEs, Bulwer's petrels exhibited higher concentrations than Cape Verde shearwaters, and chicks had higher concentration profiles than adults. Specifically, Bulwer's petrel chicks showed higher concentrations than Cape Verde shearwater chicks. On the contrary, Cape Verde shearwater adults exhibited higher occurrence and concentrations of MeO-PBDEs when compared to Cape Verde shearwater chicks. We found no effect of plastic loadings or loadings of organohalogen contaminants on body condition or size, although harmful effects may be hidden or reveal themselves in a medium- to long-term. Feather samples from both adults and chicks were shown to be useful for comparing intraspecific contamination levels and appear suitable for the long-term assessment of organohalogen contaminants in seabirds. Species-specific foraging and feeding strategies are likely the drivers of the observed variation in organochlorine contamination burdens among seabird species.

Microplastics in marine ecosystems: A comprehensive review of biological and ecological implications and its mitigation approach using nanotechnology for the sustainable environment

Microplastic contamination has rapidly become a serious environmental issue, threatening marine ecosystems and human health. This review aims to not only understand the distribution, impacts, and transfer mechanisms of microplastic contamination but also to explore potential solutions for mitigating its widespread impact. This review encompasses the categorisation, origins, and worldwide prevalence of microplastics and methodically navigates the complicated structure of microplastics. Understanding the sources of minute plastic particles infiltrating water bodies worldwide is critical for successful removal. The presence and accumulation of microplastics has far reaching negative impacts on various marine creatures, eventually extending its implications to human health. Microplastics are known to affect the metabolic activities and the survival of microbial communities, phytoplankton, zooplankton, and fauna present in marine environments. Moreover, these microplastics cause developmental abnormalities, endocrine disruption, and several metabolic disorders in humans. These microplastics accumulates in aquatic environments through trophic transfer mechanisms and biomagnification, thereby disrupting the delicate balance of these ecosystems. The review also addresses the tactics for minimising the widespread impact of microplastics by suggesting practical alternatives. These include increasing public awareness, fostering international cooperation, developing novel cleanup solutions, and encouraging the use of environment-friendly materials. In conclusion, this review examines the sources and prevalence of microplastic contamination in marine environment, its impacts on living organisms and ecosystems. It also proposes various sustainable strategies to mitigate the problem of microplastics pollution. Also, the current challenges associated with the mitigation of these pollutants have been discussed and addressing these challenges require immediate and collective action for restoring the balance in marine ecosystems.

Changes in characteristics and risk of freshwater microplastics under global warming

Microplastics present a significant threat to freshwater ecosystems. However, the impact of global warming on their characteristics and associated risks remains uncertain. This study collected 2793 sample sites from literature and datasets to create a new risk assessment and rank methodology, known as the Multi-characteristics Potential Ecological Risk Index (MPERI), which incorporates various microplastic characteristics, such as concentration, size distribution, color, shape, and polymer diversity. Using regression random forest models (RRF), this study predicted that a 10 °C increase would raise microplastic concentration from 12,465.34 ± 68,603.87 to 13,387.17 ± 60,692.96 particles/m3. The percentage of small-size microplastics initially decreased (from 69.10 % to 68.72 %) and then increased (from 68.72 % to 68.78 %), while the diversity of color, shape, and polymer decreased by 0.29 %, 3.24 %, and 0.17 %, respectively. Furthermore, global warming could increase the rank of microplastic risks from high (405.25 ± 528.9) to dangerous (535.37 ± 582.03) based on the MPERI method. Most countries would experience an increase in risk values, with Indonesia and Vietnam transitioning from low to medium risk, and China and Malaysia transitioning from high to dangerous risk. The feature importance assessment of the RRF model indicated that concentration was the most influential variable in determining the change in risk values. While other microplastic characteristics had a lesser impact compared to concentration, they still influenced the risk ranking. This study highlights the role of global warming in shaping microplastic risks.

Phthalates and fatty acid markers in free-ranging cetaceans from an insular oceanic region: Ecological niches as drivers of contamination

Plastic additives, such as phthalates, are ubiquitous contaminants that can have detrimental impacts on marine organisms and overall ecosystems' health. Valuable information about the status and resilience of marine ecosystems can be obtained through the monitoring of key indicator species, such as cetaceans. In this study, fatty acid profiles and phthalates were examined in blubber biopsies of free-ranging individuals from two delphinid species (short-finned pilot whale - Globicephala macrorhynchus, n = 45; common bottlenose dolphin - Tursiops truncatus, n = 39) off Madeira Island (NE Atlantic). This investigation aimed to explore the relations between trophic niches (epipelagic vs. mesopelagic), contamination levels, and the health status of individuals within different ecological and biological groups (defined by species, residency patterns and sex). Multivariate analysis of selected dietary fatty acids revealed a clear niche segregation between the two species. Di-n-butylphthalate (DBP), diethyl phthalate (DEP), and bis(2-ethylhexyl) phthalate (DEHP) were the most prevalent among the seven studied phthalates, with the highest concentration reached by DEHP in a bottlenose dolphin (4697.34 ± 113.45 ng/g). Phthalates esters (PAEs) concentration were higher in bottlenose dolphins (Mean ∑ PAEs: 947.56 ± 1558.34 ng/g) compared to pilot whales (Mean ∑ PAEs: 229.98 ± 158.86 ng/g). In bottlenose dolphins, DEHP was the predominant phthalate, whereas in pilot whales, DEP and DBP were more prevalent. Health markers suggested pilot whales might suffer from poorer physiological conditions than bottlenose dolphins, although high metabolic differences were seen between the two species. Phthalate levels showed no differences by ecological or biological groups, seasons, or years. This study is the first to assess the extent of plastic additive contamination in free-ranging cetaceans from a remote oceanic island system, underscoring the intricate relationship between ecological niches and contaminant exposure. Monitoring these chemicals and their potential impacts is vital to assess wild population health, inform conservation strategies, and protect critical species and habitats.

Spatial distribution of microplastics in the Gulf of Cadiz as a function of their density: A Lagrangian modelling approach

Microplastics (MPs) are distributed throughout the world oceans and represent one of the greatest environmental concerns of marine pollution. In the Gulf of Cadiz (GoC), MPs are found throughout the water column, on the seafloor, and accumulated within commercial marine species, primarily due to discharges from the main estuaries. The aim of this study was to analyse the transport pathways, spatial distribution, and accumulation regions of MPs in the GoC based on their density and source. For this, a Lagrangian transport model was coupled to a high-resolution hydrodynamic model and four particle sources were considered: Cape San Vicente, Guadiana Estuary, Guadalquivir Estuary, and Bay of Cadiz/Guadalete River. To account for the diversity of plastics detected in the GoC, particles with ten different densities were used, from low-density to high-density polymers. This study indicates that a significant proportion of low-density MPs accumulate near their sources and within the top few centimetres of the water column due to local surface currents. The Guadalquivir and Guadiana estuaries are the primary contributors to the high accumulation of low-density MPs on the GoC eastern shelf, consistent with previous field studies identifying these estuaries as the main sources of MPs into the region, including polyethylene and polypropylene. In contrast, the Bay of Cadiz/Guadalete River seems to be the primary source of low-density MPs in offshore waters within the uppermost meter of the water column, influenced by local mesoscale features. The Guadalquivir Estuary seems to be the main source of high-density MPs into the continental shelves, such as polystyrene, polyamide, and polyvinyl chloride, followed by the Bay of Cadiz/Guadalete River, and to a lesser extent, the Guadiana estuary. These MPs accumulate near their sources at depths of 3.5 to 50 m due to their high sinking rates, but can also be transported offshore by deep currents, either northwards along the Portuguese offshore waters or westwards off the GoC offshore region.

Ingestion of chitosan-starch blends: Effect on the survival of supralittoral amphipods

Sandy beach ecosystems are particularly affected by plastic pollution. Supralittoral amphipods are important components of the food web in sandy beaches and their ability to ingest microplastics and bioplastics has been assessed. Chitosan, a polysaccharide obtained by deacetylation of chitin, the second most abundant polymer in the world, represents an interesting component to produce novel bioplastics in combination with other biopolymers like starch. Here, the possibility of ingesting chitosan-starch blends and the possible effects on the amphipod Talitrus saltator were investigated. Groups of adult individuals were fed with sheets containing mixtures of chitosan and starch in different percentages for 7 and 14 days. The results showed that chitosan ingestion is dependent on the percentage of starch present in the mixture. Moreover, FTIR analyses of both sheets and faecal pellets after consumption show that chitosan is not digested. Furthermore, the survival rate of amphipods fed with a mixture of chitosan and starch decreases after one week compared to the control groups (100 % starch and paper), and drops drastically to 0 % after two weeks the experiment began. In addition, consumption of 100 % chitosan is negligible. Therefore, the results of the experimental observations evidenced that chitosan is avoided as food resource and its consumption significantly affects the survival capacity of T. saltator. It is emphasized that the release of mixtures of chitosan and starch into the marine environment appears to be dangerous for littoral amphipods.

The role of algae in regulating the fate of microplastics: A review for processes, mechanisms, and influencing factors

As an important emerging pollutant, the fate of microplastics (MPs) in ecosystems is of growing global concern. In addition to hydrodynamics and animals, algae can also affect the transport of MPs in aquatic environments, which could potentially remove MPs from the water column. Although researchers have conducted many studies on the sink of MPs regulated by algae in both marine and freshwater environments, there is still a lack of comprehensive understanding coupled with the increasingly scattered study contents and findings. This review aims to provide a systematic discussion of the processes, mechanisms, and influencing factors, which are coupled with the sink of MPs changes by algae. The main processes identified include retention, flocculation, deposition, and degradation. The retention of MPs is achieved by adhesion of MPs to algae or embedment/encrustation of MPs within the epibiont matrix of algae, thereby preventing MPs from migrating with water currents. The extracellular polymeric substances (EPS) and enzymes produced by algal metabolic activities can lead not only to the formation of aggregates containing MPs but also to the biodegradation of MPs. The processes that algae alter the fate of MPs in aquatic environments are very complex and can be influenced by various factors such as algal attributes, microplastic characteristics and environmental conditions. This review provides insights into recent advances in the fate of aquatic MPs and highlights the need for further research on MPs-algae interactions, potentially shortening the knowledge gap in the sink of MPs in aquatic ecosystems.

The impact of co-exposure to polystyrene microplastics and norethindrone on gill histology, antioxidant capacity, reproductive system, and gut microbiota in zebrafish (Danio rerio)

In recent years, studies have focused on the combined ecological risks posed by microplastics and other organic pollutants. Although both microplastics and progestin residues are frequently detected in the aquatic environments, their ecological implications remain unknown. Adult zebrafish were exposed to polystyrene microplastics (PS, 200 nm, 200 μg/L), norethindrone (NET, 69.6 ng/L), and their mixture (200 μg/L PS + 63.1 ng/L NET) for 30 days. The results demonstrated that exposure to PS and NET resulted in gill damage. Notably, the PS and PS+NET exhibited a significant decrease in glutathione (GSH) and oxidized glutathione (GSSG) content, as well as reduced antioxidase activity in the gills. The oxidative stress in PS+NET primarily originated from PS. The PS, NET, or their mixture resulted in a decrease in testosterone (T) and estradiol (E2) levels in female. Furthermore, compared to NET, the PS+NET showed a significant reduction in E2 levels, thereby augmenting the inhibitory effect on reproductive ability mediated by NET. However, males showed an increase in 11-ketodihydrotestosterone (11-KT) content, accompanied by a significant decrease in spermatogonia (Sg) and increase in spermatocytes (Sc). Consequently, it can be inferred that PS enhances the androgenic effect of NET. In female fish brain, NET alone resulted in transcriptional down-regulation of partial hormone receptors; however, co-administration of PS effectively mitigated the interference effects. Furthermore, transcriptional downregulation of 17-alpha-hydroxylase (cyp17), hydroxysteroid 3-beta dehydrogenase (hsd3b), estrogen receptor 1 (esr1), and estrogen receptor 2a (esr2b) genes in the ovary was found to be associated with the androgenic activity induced by NET. Moreover, in comparison to PS or NET alone, PS+NET resulted in a notable decrease in Cetobacterium abundance and an increase in Aeromonas population, suggesting that the co-exposure of PS+NET may exacerbate intestinal burden. The findings highlight the importance of studying the combined toxicity of PS and NET.

Research priorities on microplastics in marine and coastal environments: An Australian perspective to advance global action

Plastic and microplastic contamination in the environment receive global attention, with calls for the synthesis of scientific evidence to inform actionable strategies and policy-relevant practices. We provide a systematic literature review on microplastic research across Australian coastal environments in water, sediment and biota, highlighting the main research foci and gaps in information. At the same time, we conducted surveys and workshops to gather expert opinions from multiple stakeholders (including researchers, industry, and government) to identify critical research directions to meet stakeholder needs across sectors. Through this consultation and engagement process, we created a platform for knowledge exchange and identified three major priorities to support evidence-based policy, regulation, and management. These include a need for (i) method harmonisation in microplastic assessments, (ii) information on the presence, sources, and pathways of plastic pollution, and (iii) advancing our understanding of the risk of harm to individuals and ecosystems.

A systematic review on the impact of micro-nanoplastics on human health: Potential modulation of epigenetic mechanisms and identification of biomarkers

Epigenetic-mediated modifications, induced by adverse environmental conditions, significantly alter an organism's physiological mechanisms. Even after elimination of the stimulus, these epigenetic modifications can be inherited through mitosis, thereby triggering transgenerational epigenetics. Plastics, with their versatile properties, are indispensable in various aspects of daily life. However, due to mismanagement, plastics have become so ubiquitous in the environment that no ecosystem on Earth is free from micro-nanoplastics (MNPs). This situation has raised profound concerns regarding their potential impact on human health. Recently, both in vivo animal and in vitro human cellular models have shown the potential to identify the harmful effects of MNPs at the genome level. The emerging epigenetic impact of MNP exposure is characterized by short-term alterations in chromatin remodelling and miRNA modulation. However, to understand long-term epigenetic changes and potential transgenerational effects, substantial and more environmentally realistic exposure studies are needed. In the current review, the intricate epigenetic responses, including the NHL-2-EKL-1, NDK-1-KSR1/2, and WRT-3-ASP-2 cascades, wnt-signalling, and TGF- β signalling, established in model organisms such as C. elegans, mice, and human cell lines upon exposure to MNPs, were systematically examined. This comprehensive analysis aimed to predict human pathways by identifying human homologs using databases and algorithms. We are confident that various parallel miRNA pathways, specifically the KSR-ERK-MAPK pathway, FOXO-Insulin cascade, and GPX3-HIF-α in humans, may be influenced by MNP exposure. This influence may lead to disruptions in key metabolic and immune pathways, including glucose balance, apoptosis, cell proliferation, and angiogenesis. Therefore, we believe that these genes and pathways could serve as potential biomarkers for future studies. Additionally, this review emphasizes the origin, dispersion, and distribution of plastics, providing valuable insights into the complex relationship between plastics and human health while elaborating on the epigenetic impacts.

Occurrence of microplastics in the Haima cold seep area of the South China Sea

The pollution of deep-sea microplastics has received increasing attention. As a special ecosystem in the deep sea, the cold seep area is of great significance for studying the distribution of microplastics in the deep sea. In this work, the distribution and characteristics of microplastics in seawater, sediments, and shellfish in the Haima cold seep area and the correlation between the characteristics of microplastics in different media and the type of media were studied. Microplastics were found in all three media. The abundance of microplastics in different samples from the Haima cold seep area ranged 1.8-3.8 items/L for the seawater, 11.47-96.8 items/kg (d.w.) for the surface sediments, and 0-5 items/individual (0-0.714 items/g) for the shellfish. The amount of microplastics ingested by shellfish varied among different species. The microplastics in these three media were mainly fibrous, dark-colored, small-sized rayon, polyethylene terephthalate (PET), and polyethylene (PE). In the correlation analysis of microplastic characteristics among the three media, it was found that the characteristics of microplastics in different media in the same area were closely related, and each pair of variables showed a significant positive correlation (P ≤ 0.05). The distinctive geographical conditions would accelerate the interchange of microplastics among various media. Principal component analysis showed that habitat contribute to microplastic feature differences in shellfish. Differences in correlation were observed between the characteristics of shellfish microplastics in different regions and the characteristics of microplastics in surrounding seawater and sediments.

Effects of microplastics on typical macrobenthos in sargassum ecosystems

Recently, microplastics (MPs) have attracted extensive attention to their wide distribution and potential toxicity in ecosystems. However, there was a lack of research focused on MPs in seaweed bed ecosystems. This study investigated the distribution and toxicity of MPs in macrobenthos in Sargassum ecosystem. According to the in-situ investigation results, the abundance of MPs in the sediment was 0.9-2.3 items/g, the indoor microcosmic experiment was constructed. After exposure to MPs (0, 2, and 20 items/g) for 30 days, the abundance of MPs in macrobenthos exhibits a concentration-dependent increase. However, there was no significant bioaccumulation of MPs at the trophic level. The indoor toxicity test revealed that MPs induced oxidative stress and altered intestinal microflora composition in macrobenthos, even at actual environmental concentrations (2 items/g). It may result in a perturbation of the organism's homeostatic equilibrium. High-concentration (20 items/g) MPs had a greater impact on alkaline phosphatase (AKP) in Mollusks. The increase in AKP activity could be indicative of an adaptive mechanism in some macrobenthos while the decline in AKP activity might signal a decrease in their survival. These results elucidated the fate of MPs in ecosystem and the ecological risks of MPs to large benthic animals on model environmental conditions.

Navigating a Microplastic Sea: How the Pacific Cupped Oyster (Magallana gigas) Respond to Microplastic Pollution in Lagoons

Microplastic pollution poses an escalating concern, particularly in coastal lagoons rich in biodiversity. This study delved into the occurrence of microplastics (MPs) in Magallana gigas (formerly Crassostrea gigas) from the Orbetello and Varano coastal lagoons (Italy), also investigating the response of these filter-feeding organisms to various colors (P = pink; B = blue; W = white) of high-density polyethylene (HDPE) MP fragments. Oysters were exposed for 7 days under controlled conditions. Subsequently, the oysters underwent analysis for both MP presence and biochemical markers of oxidative stress. Diverse ingestion rates of HDPE were noted among oysters from the two lagoons, eliciting antioxidant responses and modifying baseline activity. The two-way ANOVA revealed the significant effects of treatment (control; HDPE_B; HDPE_P; HDPE_W), site, and the interaction between treatment and site on all biomarkers. Non-metric multidimensional scaling showed a divergent effect of HDPE color on biomarkers. Further investigation is warranted to elucidate the mechanisms underlying the influence of MP color, dose-dependent effects, and the long-term impacts of exposure. Comprehending these intricacies is imperative for devising effective strategies to mitigate plastic pollution and safeguard marine health.

Stability and release mechanism of double emulsification (W1/O/W2) for biodegradable pH-responsive polyhydroxybutyrate/cellulose acetate phthalate microbeads loaded with the water-soluble bioactive compound niacinamide

Microbeads of biodegradable polyhydroxybutyrate (PHB) offer environmental benefits and economic competitiveness. The aim of this study was to encapsulate a water-soluble bioactive compound, niacinamide (NIA), in a pH-responsive natural matrix composed of PHB and cellulose acetate phthalate (CAP) by double emulsification (W1/O/W2) to improve the encapsulation efficiency (%EE) and loading capacity (%LC). PHB was produced in-house by Escherichia coli JM109 pUC19-23119phaCABA-04 without the inducing agent isopropyl β-D-1-thiogalactopyranoside (IPTG). The influences of PHB and polyvinyl alcohol (PVA) concentrations, stirring rate, PHB/CAP ratio and initial NIA concentration on the properties of NIA-loaded pH-responsive microbeads were studied. The NIA-loaded pH-responsive PHB/CAP microbeads exhibited a spherical core-shell structure. The average size of the NIA-loaded pH-responsive microbeads was 1243.3 ± 11.5 μm. The EE and LC were 33.3 ± 0.5 % and 28.5 ± 0.4 %, respectively. The release profiles of NIA showed pH-responsive properties, as 94.2 ± 3.5 % of NIA was released at pH 5.5, whereas 99.3 ± 2.4 % of NIA was released at pH 7.0. The NIA-loaded pH-responsive PHB/CAP microbeads were stable for >90 days at 4 °C under darkness, with NIA remaining at 73.65 ± 1.86 %. A cytotoxicity assay in PSVK1 cells confirmed that the NIA-loaded pH-responsive PHB/CAP microbeads were nontoxic at concentrations lower than 31.3 μg/mL, in accordance with ISO 10993-5.

Developmental toxicity and potential mechanisms exposed to polystyrene microplastics and polybrominated diphenyl ethers during early life stages of fat greenling (Hexagrammos otakii)

The occurrence of microplastics (MPs) in aquatic ecosystems and their ability to absorb hydrophobic pollutants, such as persistent organic pollutants (POPs), is currently a significant concern. MPs, which are the main breakdown product of plastics, have been frequently detected in the environment, posing serious threats to organisms' health. One particular pollutant, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), is a dominant congener of PBDEs and is highly toxic to organisms. However, there is limited knowledge regarding the exposure of marine fishes to PBDEs through MPs and their combined toxic effects. In this study, the embryo toxicity of Hexagrammos otakii was conducted to investigate the combined effects of MPs and BDE-47. The results showed that MPs and BDE-47 co-exposure had detrimental effects on embryonic development, such as reduced hatchability, increased mortality, decreased heart rate, and body malformation. Moreover, the combined toxicity of these substances appeared more pronounced harmful effects compared to exposure to BDE-47 alone. Histopathological examination revealed that co-exposure can cause greater damage to hatching glands and yolk. The enrichment of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways included phagosome, metabolism of xenobiotics by cytochrome P450, TCA cycle, and Wnt signaling pathway, which are closely related to embryonic growth. BDE-47 and MPs may activate the Wnt signaling pathway to affect the normal development of embryos. Our results suggest that MPs and BDE-47 exposure may cause growth disorders in the early life stages of H.otakii, leading to abnormal embryonic development. All these results will contribute to the further study of the ecological risk assessment and toxicity of MPs and organic pollutant mixtures in marine fish.

A Quantitative Analysis of Microplastics in the Gastrointestinal Tracts of Odontocetes in the Southeast Region of the United States

Microplastics (<5 mm in diameter) are ubiquitous in the oceanic environment, yet microplastic accumulation in marine mammals is vastly understudied. In recent years, efforts have been made to document microplastic profiles in odontocetes. The objective of the present study was to describe and quantify microplastics in the gastrointestinal (GI) tracts of deceased odontocetes that stranded in the southeastern United States. Our study included 24 bottlenose dolphins (Tursiops truncatus), two pygmy sperm whales (Kogia breviceps), one pantropical spotted dolphin (Stenella attenuata), one short-snouted spinner dolphin (Stenella clymene), one Risso's dolphin (Grampus griseus), and one dwarf sperm whale (Kogia sima) obtained from stranding networks in Texas, Alabama, Florida, and Puerto Rico. Contents found in the GI tracts, namely, the stomach and portions of the intestinal tract, were subjected to a laboratory procedure to isolate microplastics. The physical characteristics of microparticles were analyzed with a stereomicroscope, and microplastics were classified by polymer type via Fourier-transform infrared spectroscopy. There was an average of 47.6 ± 41.4 microparticles, ranging from 1 to 193 items per stomach. More specifically, there was an average of 5.6 ± 4.7 microplastics per stomach. The predominant morphologies, colors, and polymer types were fibers, white-colored items, and polyester, respectively. This research contributes to the current knowledge of microplastic exposure in top marine mammal predators and sets the stage for further exploration into the associated risks of microplastics in odontocetes within the United States and worldwide. Environ Toxicol Chem 2024;43:1260-1273. © 2024 SETAC.

Development of a New Aggregation Method to Remove Nanoplastics from the Ocean: Proof of Concept Using Mussel Exposure Tests

The overproduction and mismanagement of plastics has led to the accumulation of these materials in the environment, particularly in the marine ecosystem. Once in the environment, plastics break down and can acquire microscopic or even nanoscopic sizes. Given their sizes, microplastics (MPs) and nanoplastics (NPs) are hard to detect and remove from the aquatic environment, eventually interacting with marine organisms. This research mainly aimed to achieve the aggregation of micro- and nanoplastics (MNPs) to ease their removal from the marine environment. To this end, the size and stability of polystyrene (PS) MNPs were measured in synthetic seawater with the different components of the technology (ionic liquid and chitosan). The MPs were purchased in their plain form, while the NPs displayed amines on their surface (PS NP-NH2). The results showed that this technology promoted a significant aggregation of the PS NP-NH2, whereas, for the PS MPs, no conclusive results were found, indicating that the surface charge plays an essential role in the MNP aggregation process. Moreover, to investigate the toxicological potential of MNPs, a mussel species (M. galloprovincialis) was exposed to different concentrations of MPs and NPs, separately, with and without the technology. In this context, mussels were sampled after 7, 14, and 21 days of exposure, and the gills and digestive glands were collected for analysis of oxidative stress biomarkers and histological observations. In general, the results indicate that MNPs trigger the production of reactive oxygen species (ROS) in mussels and induce oxidative stress, making gills the most affected organ. Yet, when the technology was applied in moderate concentrations, NPs showed adverse effects in mussels. The histological analysis showed no evidence of MNPs in the gill's tissues.

Microbiota in different digestive tract of paddlefish (Polyodon spathula) are related to their functions

Paddlefish has high economic and ecological value. In this study, microbial diversity and community structure in intestine, stomach, and mouth of paddlefish were detected using high-throughput sequencing. The results showed that the diversity and richness indices decreased along the digestive tract, and significantly lower proportion of those were observed in intestine. Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla. In top 10 phyla, there was no significant difference in mouth and stomach. But compared with intestine, there were significant differences in 8 of the 10 phyla, and Firmicutes and Bacteroidetes increased significantly, while Proteobacteria decreased significantly. There was no dominant genus in mouth and stomach, but Clostridium_sensu_stricto_1 and uncultured_bacterium_o_Bacteroidales was predominant in intestine. In conclusion, the species and abundance of microbiota in the mouth and stomach of paddlefish were mostly the same, but significantly different from those in intestine. Moreover, there was enrichment of the dominant bacteria in intestine.

Polyethylene microplastics alter root functionality and affect strawberry plant physiology and fruit quality traits

Strawberry, a globally popular crop whose fruit are known for their taste and health benefits, were used to evaluate the effects of polyethylene microplastics (PE-MPs) on plant physiology and fruit quality. Plants were grown in 2-L pots with natural soil mixed with PE-MPs at two concentrations (0.2% and 0.02%; w/w) and sizes (⌀ 35 and 125 µm). Plant physiological responses, root histochemical and anatomical analyses as well as fruit biometric and quality features were conducted. Plants subjected to ⌀ 35 µm/0.2% PE-MPs exhibited the most severe effects in terms of CO2 assimilation due to stomatal limitations, along with the highest level of oxidative stress in roots. Though no differences were observed in plant biomass, the impact on fruit quality traits was severe in ⌀ 35 µm/0.2% MPs treatment resulting in a drop in fruit weight (-42%), soluble solid (-10%) and anthocyanin contents (-25%). The smallest sized PE-MPs, adsorbed on the root surface, impaired plant water status by damaging the radical apparatus, which finally resulted in alteration of plant physiology and fruit quality. Further research is required to determine if these alterations also occur with other MPs and to understand more deeply the MPs influence on fruit physio-chemistry.

Transcriptomic and metabolomic analysis unveils nanoplastic-induced gut barrier dysfunction via STAT1/6 and ERK pathways

The widespread prevalence of micro and nanoplastics in the environment raises concerns about their potential impact on human health. Recent evidence demonstrates the presence of nanoplastics in human blood and tissues following ingestion and inhalation, yet the specific risks and mechanisms of nanoplastic toxicity remain inadequately understood. In this study, we aimed to explore the molecular mechanisms underlying the toxicity of nanoplastics at both systemic and molecular levels by analyzing the transcriptomic/metabolomic responses and signaling pathways in the intestines of mice after oral administration of nanoplastics. Transcriptome analysis in nanoplastic-administered mice revealed a notable upregulation of genes involved in pro-inflammatory immune responses. In addition, nanoplastics substantially reduced the expression of tight junction proteins, including occludin, zonula occluden-1, and tricellulin, which are crucial for maintaining gut barrier integrity and function. Importantly, nanoplastic administration increased gut permeability and exacerbated dextran sulfate sodium-induced colitis. Further investigation into the underlying molecular mechanisms highlighted significant activation of signaling transsducer and activator of transcription (STAT)1 and STAT6 by nanoplastic administration, which was in line with the elevation of interferon and JAK-STAT pathway signatures identified through transcriptome enrichment analysis. Additionally, the consumption of nanoplastics specifically induced nuclear factor kappa-B (NF-κB) and extracellular signal-regulated kinase (ERK)1/2 signaling pathways in the intestines. Collectively, this study identifies molecular mechanisms contributing to adverse effects mediated by nanoplastics in the intestine, providing novel insights into the pathophysiological consequences of nanoplastic exposure.

The power of Posidonia oceanica meadows to retain microplastics and the consequences on associated macrofaunal benthic communities

In the coastal environment, a large amount of microplastics (MPs) can accumulate in the sediments of seagrass beds. However, the potential impact these pollutants have on seagrasses and associated organisms is currently unknown. In this study, we investigated the differences in MPs abundance and composition (i.e., shape, colour and polymer type) in marine sediments collected at different depths (-5 m, -15 m, -20 m) at two sites characterized by the presence of Posidonia oceanica meadows and at one unvegetated site. In the vegetated sites, sediment samples were collected respectively above and below the upper and lower limits of the meadow (-5 m and -20 m), out of the P. oceanica meadow, and in the central portion of the meadow (-15 m). By focusing on the central part of the meadow, we investigated if the structural features (i.e. shoots density and leaf surface) can affect the amount of MPs retained within the underlying sediment and if these, in turn, can affect the associated benthic communities. Results showed that the number of MPs retained by P. oceanica meadows was higher than that found at the unvegetated site, showing also a different composition. In particular, at vegetated sites, we observed that MPs particles were more abundant within the meadow (at - 15 m), compared to the other depths, on unvegetated sediment, with a dominance of transparent fragments of polypropylene (PP). We observed that MPs entrapment by P. oceanica was accentuated by the higher shoots density, while the seagrass leaf surface did not appear to have any effect. Both the abundance and richness of macrofauna associated with P. oceanica rhizomes appear to be negatively influenced by the MPs abundance in the sediment. Overall, this study increases knowledge of the potential risks of MPs accumulation in important coastal habitats such as the Posidonia oceanica meadows.

Graphene-based nanomaterials for the removal of emerging contaminants of concern from water and their potential adaptation for point-of-use applications

Considering the plethora of work on the exceptional environmental performance of 2D nanomaterials, there is still a missing link in addressing their practical application in point-of-use (POU) water treatment. By reviewing the exceptional environmental performance of 2D nanomaterials with specific emphasis on graphene and its derivatives, this review aims at inspiring further discussions and research in graphene-based POU water treatment with particular focus on the removal of emerging contaminants of concern (ECCs), which is largely missing in the literature. We outlined the prevalence of ECCs in the environment, their health effects both on humans and marine life, and the potential of efficiently removing them from water using three-dimensional graphene-based macrostructures to ensure ease of adsorbent recovery and reuse compared to nanostructures. Given various successful studies showing superior adsorption capacity of graphene nanosheets, we give an account of the recent developments in graphene-based adsorbents. Moreover, several cost-effective materials which can be easily self-assembled with nanosheets to improve their environmental performance and safety for POU water treatment purposes were highlighted. We highlighted the strategy to overcome challenges of adsorbent regeneration and contaminant degradation; and concluded by noting the need for policy makers to act decisively considering the conservative nature of the water treatment industry, and the potential health risks from ingesting ECCs through drinking water. We further justified the need for the development of advanced POU water treatment devices in the face of the growing challenges regarding ECCs in surface water, and the rising cases of drinking water advisories across the world.

Are we eating plastic? Science mapping of microplastic pollution in the aquatic food chain

This study evaluates the knowledge structure of microplastic pollution and its effects on the aquatic food chain. The presence of microplastics has seriously harmed the ecosystem. Through bibliometric analysis, 216 journal publications were retrieved from the Web of Science (WoS) from 2008 to 2023 (April), with no restriction in the time frame. Applying bibliographic coupling and co-word analysis, the emerging, current, and future themes of microplastic pollution are presented. Three research streams are derived from bibliographic coupling, centralized on the source of microplastic pollution and its impact. At the same time, research streams from co-word analysis are associated with overcoming the issue of microplastics in the ecosystem. This study's implications suggest three main principles to mitigate microplastic issues: (1) educating the public on the impact of microplastic pollution, (2) implementing holistic regulations and policies, and (3) developing treatment strategies through conventional, innovative, and hybrid approaches. Microplastic pollution is a global concern, requiring a holistic and comprehensive approach to overcome it. This review is the first to present a scientific mapping of the microplastics literature, which is a fundamental basis for future research on microplastic pollution and its impact on the ecosystem. Integr Environ Assess Manag 2024;00:1-12. © 2024 SETAC.

Microplastics are detected in human gallstones and have the ability to form large cholesterol-microplastic heteroaggregates

Ubiquitous pollution due to microplastics through the food chain is a major cause of various deleterious effects on the human health. The aim of this study was to determine the existence of microplastics and the internal mechanism of microplastics as accelerators of cholelithiasis. Gallstones were collected from 16 patients after cholecystectomy, and microplastics in the gallstones were detected through laser direct infrared and pyrolysis gas chromatographymass spectrometry examinations. Mice model of gallstone were constructed with or without different diameters of microplastic (0.5, 5 and 50 µm). The affinity between microplastic and cholesterol or bilirubin was tested by co-culturing and qualified using molecular dynamics simulations. Finally, altered gut microbiota among the groups were identified using 16 s rRNA sequencing. The presence of microplastics in the gallstones of all the patients were confirmed. Microplastic content was significantly higher in younger chololithiasis patients (age<50 years). Mice fed a high-cholesterol diet with microplastic drinks showed more severe chololithiasis. In terms of the mechanism, microplastics showed a higher affinity for cholesterol than for bilirubin. Significant alterations in the gut microbiota have also been identified after microplastic intake in mice. Our study revealed the presence of microplastics in human gallstones, showcasing their potential to aggravate chololithiasis by forming large cholesterol-microplastic heteroaggregates and altering the gut microbiota.

At-sea solid waste production by a small-scale fishery in Peru

Marine litter is a growing environmental problem for which fisheries-sourced waste remains poorly understood. In Peru, there is an ongoing challenge of waste management from the small-scale fisheries fleet given the lack of facilities to receive the variety of debris produced by fishers, which includes hazardous wastes such as batteries. In this study, onboard solid waste production was monitored daily by land-based observers upon landing at the port of Salaverry, Peru, from March to September 2017. The analysed small-scale gillnet and longline fishing fleets produced annually an estimated 11,260 kg of solid waste. Of particular concern is the production of single use plastics (3427 kg) and batteries (861 kg) due to their potential long-lasting impacts on the environment and challenges related to their proper disposal. A management plan for solid waste has been developed for Salaverry; therefore, a subsequent assessment was conducted in 2021-2022 of the behaviours and perceptions of fishers regarding the implementation of this plan. Most fishers (96%) reported disposing of their waste on land, except organic waste which is disposed of at sea. While fishers in Salaverry have become more conscious of the issues surrounding at-sea waste disposal and have an interest in better segregating and managing their waste, there remains a need for improved waste management and recycling protocols and procedures at the port to make this possible.

Occurrence of microplastics in fish gastrointestinal tracts belongs to different feeding habits from the Bangladesh coast of the Bay of Bengal

The Bay of Bengal (BoB) is home to a range of commercially important species with different food habits and feeding features. Microplastic (MP) contamination in the fish of BoB, like in many other marine environments, is a significant environmental concern. The study aimed to investigate the presence of microplastics (MPs) in the gastrointestinal tracts (GITs) of selected commercial marine fishes from the Bangladesh coast of the BoB. Six fish species (Escualosa thoracata, Tenualosa ilisha, Johnius belangerii, Trichiurus lepturus, Planiliza parsia, and Mystus gulio) were investigated (n = 120) following hydrogen peroxide digestion, and floatation (saline solution) protocols. After analyses, a total number of 696 MPs (dimension 0.3 to 5 mm) were identified. Moreover, the highest occurrence of MPs in fish GITs was found in planktivorous fish (average of 7.7 items/individual), followed by omnivorous (average of 5.2 items/individual), and carnivorous fish (average of 4.6 items/individual) (p < 0.001). However, planktivorous E. thoracata showed the highest number of MPs per g of GIT (average of 30.99 items/g GIT), whereas T. ilisha showed the lowest count (average of 0.77 items/g GIT). Different types of MPs (fibers (19 to 76%), fragments (6 to 61%), films (8 to 35%), microbeads (0 to 5%), and foams (0 to 2%)) were also observed. In terms of the color of MPs, the transparent, black, green, and blue types were the most common. Polymers were found as polyethylene (35 to 43%), polyethylene terephthalate (28 to 35%), polyamide (20 to 31%), and polystyrene (0 to 7%). The study provides a significant incidence of MPs in fish from the Bangladesh part of the BoB, which is very concerning. Therefore, long-term research is indispensable to ascertain the variables affecting the presence of MPs in fish, their origins, and their potential effects on the BoB fisheries. Stringent policies on plastic use and disposal should be strongly urged in this coastal region.

Polyethylene nanoparticles at environmentally relevant concentrations enhances neurotoxicity and accumulation of 6-PPD quinone in Caenorhabditis elegans

The exposure risk of 6-PPD quinone (6-PPDQ) has aroused increasing concern. In the natural environment, 6-PPDQ could interact with other pollutants, posing more severe environmental problems and toxicity to organisms. We here examined the effect of polyethylene nanoplastic (PE-NP) on 6-PPDQ neurotoxicity and the underling mechanisms in Caenorhabditis elegans. In nematodes, PE-NP (1 and 10 μg/L) decreased locomotion behavior, but did not affect development of D-type neurons. Exposure to PE-NP (1 and 10 μg/L) strengthened neurotoxicity of 6-PPDQ (10 μg/L) on the aspect of locomotion and neurodegeneration induction of D-type motor neurons. Exposure to PE-NPs (10 μg/L) caused increase in expressions of mec-4, asp-3, and asp-4 governing neurodegeneration in 10 μg/L 6-PPDQ exposed nematodes. Moreover, exposure to PE-NP (10 μg/L) increased expression of some neuronal genes (daf-7, dbl-1, jnk-1, and mpk-1) in 6-PPDQ exposed nematodes, and RNAi of these genes resulted in susceptibility to neurotoxicity of PE-NP and 6-PPDQ. 6-PPDQ could be adsorbed by PE-NPs, and resuspension of PE-NP and 6-PPDQ after adsorption equilibrium exhibited similar neurotoxicity to co-exposure of PE-NP and 6-PPDQ. In addition, exposure to PE-NP (1 and 10 μg/L) increased 6-PPDQ accumulation in body of nematodes and increased defecation cycle length in 6-PPDQ exposed nematodes. Therefore, 6-PPDQ could be adsorbed on nanoplastics (such as PE-NPs) and enhance both neurotoxicity and accumulation of 6-PPDQ in organisms.

Accumulation of microplastics in predatory birds near a densely populated urban area

The pollution due to plastic and other anthropogenic particles has steadily increased over the last few decades, presenting a significant threat to the environment and organisms, including avian species. This research aimed to investigate the occurrence of anthropogenic pollutants in the digestive and respiratory systems of four birds of prey: Common Buzzard (Buteo buteo), Black Kite (Milvus migrans), Eurasian Sparrowhawk (Accipiter nisus), and Northern Goshawk (Accipiter gentilis). The results revealed widespread contamination in all species with microplastics (MPs) and cellulosic anthropogenic fibers (AFs), with an average of 7.9 MPs and 9.2 AFs per specimen. Every digestive system contained at least one MP, while 65 % of specimens exhibited MPs in their respiratory systems. This is the work reporting a high incidence of MPs in the respiratory system of birds, clearly indicating inhalation as a pathway for exposure to plastic pollution. The content of MPs and AFs varied significantly when comparing specimens collected from central Madrid with those recovered from other parts of the region, including rural environments, suburban areas, or less populated cities. This result aligns with the assumption that anthropogenic particles disperse from urban centers to surrounding areas. Additionally, the dominant particle shape consisted of small-sized fibers (> 98 %), primarily composed of polyester, polyethylene, acrylic materials, and cellulose fibers exhibiting indicators of industrial treatment. These findings emphasize the necessity for further research on the impact of plastic and other anthropogenic material contamination in avian species, calling for effective strategies to mitigate plastic pollution.

Trophic transfer and interfacial impacts of micro(nano)plastics and per-and polyfluoroalkyl substances in the environment

Both micro(nano)plastics (MNPs) and per-and polyfluoroalkyl substances (PFAS) possessed excellent properties and diverse applications, albeit gained worldwide attention due to their anthropogenic, ubiquitous, degradation resistant nature and a wide variety of ecological and human health impacts. MNPs and PFAS discharged from discrete sources and extensively bioaccumulated in the food chain through trophic transfer and their long-distance transport potential assist in their dispersal to pristine but vulnerable ecosystems such as Antarctica. They inevitably interacted with each other in the environment through polarized N-H bond, hydrogen bond, hydrophobic interaction, and weak bond energies such as Van der Waals, electrostatic, and intramolecular forces. During co-exposure, they significantly impact the uptake and bioaccumulation of each other in exposed organisms, which may increase or decrease their bioavailable concentration. Hence, this review compiles the studies on the co-occurrence and adsorption of PFAS and MNPs in the environment, their trophic transfer, combined in vivo and in vitro impacts, and factors influencing the MNP-PFAS interface. A significant proportion of studies were conducted in China, Europe, and the US, while studies are rare from other parts of the world. Freshwater and marine food chains were more prominently investigated for trophic transfers compared to terrestrial food chains. The most notable in vivo effects were growth and reproductive impairment, oxidative stress, neurotoxicity and apoptosis, DNA damage, genotoxicity and immunological responses, behavioral and gut microbiota modifications, and histopathological alterations. Cellular uptake of PFAS and MNPs can impact cell survival and proliferation, photosynthesis and membrane integrity, ROS generation and antioxidant responses, and extracellular polymeric substances (EPS) release in vitro. MNP characteristics, PFAS properties, tissue and species-dependent distribution, and environmental medium properties were the main factors influencing the PFAS and MNP nexus and associated impacts. Last but not least, gaps and future research directions were highlighted to better understand the interplay between these critical persistent chemicals.

Fabrication, characterization and release behavior of α-tocopherol acetate-loaded pH-responsive polyhydroxybutyrate/cellulose acetate phthalate microbeads

Microbeads are used in personal care and cosmetic products (PCCPs) but are produced from nondegradable materials. Biodegradable polyhydroxybutyrate (PHB) has been recognized as a promising alternative material for use in PCCPs; however, utilizing PHB to encapsulate PCCPs is challenging because PCCPs need to be protected from the environment but their release needs to be permitted under specific physiological conditions. The aim of this work was to develop and evaluate pH-responsive cellulose acetate phthalate (CAP) to formulate lipophilic α-tocopherol acetate (α-TA)-loaded pH-responsive PHB/CAP microbeads. The influences of the PHB/CAP ratio and initial α-TA loading on the microbead size, surface morphology, encapsulation efficiency (%EE), loading capacity (%LC), and α-TA release profile were studied. The microbeads exhibited a spherical shape with a size of 328.7 ± 2.9 μm. The EE and LC were 86.7 ± 2.6 % and 13.5 ± 0.4 %, respectively. The release profile exhibited pH-responsive characteristics. These α-TA-loaded pH-responsive microbeads were stable with >50 % of the α-TA remaining after 90 days at 4, 25 and 45 °C in the dark. The results from the cytotoxicity assay with PSVK1 cells demonstrated that the microbeads were nontoxic. Hence, our developed formulation has the potential to be used to encapsulate oil-based drugs to formulate lipophilic substance-loaded pH-responsive microbeads.

The physiological effect of polystyrene nanoplastic particles on fish and human fibroblasts

Numerous studies have identified the detrimental effects for the biosphere of large plastic debris, the effect of microplastics (MPs) and nanoplastics (NPs) is less clear. The skin is the first point of contact with NPs, and skin fibroblasts have a vital role in maintaining skin structure and function. Here, a comparative approach is taken using three fibroblast cell lines from the zebrafish (SJD.1), human male newborn (BJ-5ta) and female adult (HDF/TERT164) and their response to polystyrene NP (PS-NPs) exposure is characterized. Cells were exposed to environmentally relevant PS-NP sizes (50, 500 and 1000 nm) and concentrations (0.001 to 10 μg/ml) and their uptake (1000 nm), and effect on cell viability, proliferation, migration, reactive oxygen species (ROS) production, apoptosis, alkaline phosphatase (ALP) and acid phosphatase (AP) determined. All fibroblasts took up PS-NPs, and a relationship between PS-NP particle size and concentration and the inhibition of proliferation and cell migration was identified. The inhibitory effect of PS-NPs on proliferation was more pronounced for human skin fibroblasts. The presence of PS-NPs negatively affected fibroblast migration in a time-, size- and concentration-dependent manner with larger PS-NPs at higher concentrations causing a more significant inhibition of cell migration, with human fibroblasts being the most affected. No major changes were detected in ROS production or apoptosis in NP challenged fibroblasts. While the ALP activity was increased in all fibroblast cell lines, only fish fibroblasts showed a significant increase in AP activity. The heterogeneous response of fibroblasts induced by PS-NPs was clearly revealed by the segregation of HDF, BJ.5ta and SJD.1 fibroblasts in principal component analysis. Our results demonstrate that PS-NP exposure adversely affected cellular processes in a cell-type and dose-specific manner in distinct fibroblast cell lines, emphasizing the need for further exploration of NP interactions with different cell types to better understand potential implications for human health.

Potential Effects of Orally Ingesting Polyethylene Terephthalate Microplastics on the Mouse Heart

Polyethylene terephthalate microplastics (PET MPs) are widespread in natural environment, and can enter organisms and accumulate in the body, but its toxicity has not been well studied. Therefore, in order to investigate the toxic effects of PET microplastics on mammals, this study investigated the toxic effects of PET MPs on ICR mice and H9C2 cells by different treatment groups. The results indicated the cardiac tissue of mice in the PET-H (50 µg/mL) group showed significant capillary congestion, myocardial fiber breakage, and even significant fibrosis compared to the PET-C (control) group (P < 0.01). Results of the TUNEL assay demonstrated significant apoptosis in myocardial tissue in the PET-H and PET-M (5 µg/mL) groups (P < 0.01). Meanwhile, Western blotting showed increased expression of the apoptosis-related protein Bax and decreased expression of PARP, caspase-3, and Bcl-2 proteins in both myocardial tissues and H9C2 cells. In addition, flow cytometry confirmed that PET MPs decreased the mitochondrial membrane potential and apoptosis in H9C2 cells; however, this trend was reversed by N-acetylcysteamine application. Moreover, PET MP treatment induced the accumulation of reactive oxygen species (ROS) in H9C2 cells, while the MDA level in the myocardial tissue was elevated, and the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were decreased (P < 0.01), indicating a change in the redox environment. In conclusion, PET MPs promoted cardiomyocyte apoptosis by inducing oxidative stress and activating mitochondria-mediated apoptotic processes, ultimately leading to myocardial fibrosis. This study provides ideas for the prevention of PET MP toxicity and promotes thinking about enhancing plastic pollution control.

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.

Long-term investigation of microplastic abundance in Squalius species in Turkish inland waters

Examining the enduring alterations in microplastic (MP) concentrations within fish in inland waters is of utmost importance in understanding the historical trajectory of plastic waste and formulating consequential predictions regarding upcoming pollution levels. This study includes the collection of fish samples from 22 different river basins in Türkiye and all Squalius species distributed in Türkiye, covering the years 2004-2018, and examined the presence of MP in museum specimens' gastrointestinal tracts (GITs). 331 specimens were examined, and microplastic was observed in 20.8% (69). A mean value of 0.27 ± 0.19 MP per individual was observed, resulting in a cumulative score of 91 MP. Most observed MPs were composed of fiber, representing 79.1% of the total. The polymer types identified were mostly polyethylene (PE) at 38.5% and polyethylene terephthalate (PET) at 29.7%. The black color was prominent among MPs, and MP length ranged between 101 and 4963 μm. The analysis revealed no statistically significant difference in the mean MP values across different years and basins. There is no substantial correlation between the abundance of MP and the sizes of fish, population density, or quantities of plastic production. The data indicate that MP has persistently acted as a contaminant in freshwater ecosystems over an extended period. It is projected that the laundering of synthetic textiles serves as the primary contributor to MP contamination in freshwater bodies. Our results offer significant baseline data on the pervasive issue of MP pollution in the freshwater environment. These findings enable us to gain profound insights into the current state of MP contamination in fish residing in lotic systems while empowering us to make accurate predictions about its future trajectory.

Preparation and characterization of astaxanthin-loaded biodegradable polyhydroxybutyrate (PHB) microbeads for personal care and cosmetic applications

Due to its biodegradability and biocompatibility, polyhydroxybutyrate (PHB) has received attention as an alternative material for microbeads in personal care and cosmetic products (PCCPs). Here, PHB was produced from crude glycerol by an Escherichia coli JM109 strain harboring pUC19-23,119-phaCABA-04 without isopropyl β-D-1-thiogalactopyranoside (IPTG), an inducing agent. Astaxanthin-loaded PHB microbeads were prepared through emulsification-solvent evaporation. Studies were performed to determine how the concentration of PHB and stirring rate influence the size, surface morphology, encapsulation efficiency (EE), and astaxanthin release profile. The astaxanthin-loaded PHB microbeads exhibited a rough surface, 98.1 ± 0.7 % EE, spherical shape and 179 ± 44 μm size. In addition, <50 % astaxanthin release was observed within 240 min. Stability studies revealed that astaxanthin-loaded microbeads retained over 85.3 ± 4.2 % of astaxanthin after 90 days at 4 °C and showed a 2-fold reduction in astaxanthin degradation compared to their unencapsulated counterparts; thus, astaxanthin-loaded microbeads show promise for PCCPs applications. A cytotoxicity assay revealed that astaxanthin-loaded PHB microbeads were nontoxic to the human epidermal keratinocyte cell line, PSVK1, and EpiSkin® cells. Skin irritation and sensitization were not observed during a human repeated insult patch test (HRIPT), according to clinical practice guidelines of the Japanese dermatological association.

A study on transboundary governance of marine plastic debris-the case of an adjacent waters between China and Taiwan

This study aimed to construct a transboundary marine governance mechanism in the Kinmen-Xiamen waters through literature review, field survey, in-depth interview, and expert opinion survey. The study finds that monsoons, ocean currents, and tides are the main factors affecting the drift of marine debris in the Xiamen Sea area to the beaches of Kinmen. The marine debris mainly included marine plastic debris (MPD), bamboo, and wood in Kinmen and was documented impacting a variety of species, including the horseshoe crab to marine mammals the IndoPacific dolphin. In addition, the problem of marine micro-plastic pollution is becoming increasingly worrisome and hazardous to rare creatures in the Xiamen Sea area. The pollution sources of MPD in Xiamen Bay included coastal tourism activities, micro-plastic discharged from sewage treatment plants, plastic waste produced by lost and discarded marine aquaculture, and plastic drifting terrestrial waste transported from the Jiulong River Basin. Our results show that microplastic pollution in the Kinmen-Xiamen waters may have a greater impact on marine ecology and the surrounding environment. The relevant transboundary marine governance mechanisms are discussed in this study.

Water striders are impervious to raindrop collision forces and submerged by collapsing craters

Water striders are abundant in areas with high humidity and rainfall. Raindrops can weigh more than 40 times the adult water strider and some pelagic species spend their entire lives at sea, never contacting ground. Until now, researchers have not systematically investigated the survival of water striders when impacted by raindrops. In this experimental study, we use high-speed videography to film drop impacts on water striders. Drops force the insects subsurface upon direct contact. As the ensuing crater rebounds upward, the water strider is propelled airborne by a Worthington jet, herein called the first jet. We show the water strider's locomotive responses, low density, resistance to wetting when briefly submerged, and ability to regain a super-surface rest state, rendering it impervious to the initial impact. When pulled subsurface during a second crater formation caused by the collapsing first jet, water striders face the possibility of ejection above the surface or submersion below the surface, a fate determined by their position in the second crater. We identify a critical crater collapse acceleration threshold ∼ 5.7 gravities for the collapsing second crater which determines the ejection and submersion of passive water striders. Entrapment by submersion makes the water strider poised to penetrate the air-water interface from below, which appears impossible without the aid of a plastron and proper locomotive techniques. Our study is likely the first to consider second crater dynamics and our results translate to the submersion dynamics of other passively floating particles such as millimetric microplastics atop the world's oceans.

Aging of plastics in aquatic environments: Pathways, environmental behavior, ecological impacts, analyses and quantifications

The ubiquity of plastics in our environment has brought about pressing concerns, with their aging processes, photo-oxidation, mechanical abrasion, and biodegradation, being at the forefront. Microplastics (MPs), whether originating from plastic degradation or direct anthropogenic sources, further complicate this landscape. This review delves into the intricate aging dynamics of plastics in aquatic environments under various influential factors. We discuss the physicochemical changes that occur in aged plastics and the release of oxidation products during their degradation. Particular attention is given to their evolving environmental interactions and the resulting ecotoxicological implications. A rigorous evaluation is also conducted for methodologies in the analysis and quantification of plastics aging, identifying their merits and limitations and suggesting potential avenues for future research. This comprehensive review is able to illuminate the complexities of plastics aging, charting a path for future research and aiding in the formulation of informed policy decisions.

Toxic effects of nanopolystyrene and cadmium on the intestinal tract of the Chinese mitten crab (Eriocheir sinensis)

Nanopolystyrene (NP) and cadmium (Cd) are ubiquitous contaminants in aquatic systems. The present study aimed to investigate the toxic effects of exposure to ambient concentrations of NP and/or Cd on the intestinal tract of the Chinese mitten crab (Eriocheir sinensis). Exposure to NP and/or Cd induced oxidative stress, as evidenced by a significant increase in lipid peroxide content (LPO), total antioxidant capacity (T-AOC), and peroxidase activity (POD), and significant decreases in superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities in E. sinensis. In addition, exposure to NP and/or Cd imbalanced the homeostasis of the intestinal microbiota, as demonstrated by the significantly increased abundance of Spiroplasma. Transcriptomic and metabolomic analyses were performed to investigate the mechanisms underlying intestinal toxicity. Our results showed that ferroptosis, ABC transporters, phosphotransferase system, apoptosis, and leukocyte transendothelial migration were disturbed after exposure to NP and/or Cd. In particular, Cd exposure affected mucin type O-glycan biosynthesis, purine metabolism, and neuroactive ligand-receptor interaction. Intriguingly, co-exposure to NP and Cd might mitigate intestinal toxicity by decreasing oxidative stress and affecting these pathways. Taken together, our study clearly demonstrates that exposure to NP and/or Cd at environmentally relevant concentrations causes intestinal toxicity in E. sinensis.

Characterization and risk assessment of microplastics in laver from the Yueqing Bay

Microplastics (MPs) pollution is regarded as a global challenge for ocean. As an important food source of human, macroalgae could suffer MP pollution and transmit MPs into human via food web. However, few studies have revealed the relationship of MP pollution between macroalgae and its habitat. In order to evaluate the trapping and accumulation of MPs in macroalgae and surface water, the present study investigated MP pollution in a typical aquaculture macroalgae species, laver (Porphyra haitanensis) in the Yueqing Bay. The results indicated MP abundance in laver (1.45 ± 0.26 items/g) was at a medium level while MP abundance in surface water (0.21 ± 0.15 item/m3) was at a relatively low level worldwide. Distribution trend and characteristics of MPs in laver and surface water showed highly similarity. Besides, heavy metal elements (Fe and Zr) were detected on the surface of MPs trapped by laver. Pollution load index (PLI) in surface water of the whole bay was low, indicating MP pollution was not serious in the Yueqing Bay. Due to the discharging of domestic sewage in recent years, fiber-shaped, textile MPs accounted for most in laver and surface water of the Yueqing Bay. These results indicated that MPs in surface water could be trapped by P. haitanensis, thus macroalgae cultivation might be a potential way to alleviate seawater MP pollution in the nearshore areas.

Plastic ingestion by three species of Scylla (Brachyura) from the coastal areas of Thailand

This study marked the first investigation into the presence of plastic particles in the stomachs of three mud crab species (Scylla olivacea, S. paramamosain and S. tranquebarica) collected across the Andaman Sea and the Gulf of Thailand. The highest number of plastic particles in the stomach of crab samples was polyethylene (PE) that contributed 88.5 %; while green was the predominant colour (60.3 %). Ingested particles recovered from the stomachs of crabs differed significantly between species and sites (p < 0.001). The average number of plastic particles per individual was 2.3 ± 8.6 in Scylla olivacea, 7.2 ± 16.9 in S. paramamosain, and 13.5 ± 48.9 in S. tranquebarica. Satun, revealed the highest number of plastic particles recovered from mud crabs, while the lowest number of plastic particles were from Pattani. To conclude, species of crab and site of collection plays a crucial factor in the propensity of plastic particles ingested by the genus Scylla mud crabs.

A comprehensive review of micro- and nano-plastics in the atmosphere: Occurrence, fate, toxicity, and strategies for risk reduction

Micro- and nano-plastics (MNPs) have received considerable attention over the past 10 years due to their environmental prevalence and potential toxic effects. With the increase in global plastic production and disposal, MNP pollution has become a topic of emerging concern. In this review, we describe MNPs in the atmospheric environment, and potential toxicological effects of exposure to MNPs. Studies have reported the occurrence of MNPs in outdoor and indoor air at concentrations ranging from 0.0065 items m-3 to 1583 items m-3. Findings have identified plastic fragments, fibers, and films in sizes predominantly <1000 μm with polyamide (PA), polyester (PES), polyethylene terephthalate (PET), polypropylene (PP), rayon, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyacrylonitrile (PAN), and ethyl vinyl acetate (EVA) as the major compounds. Exposure through indoor air and dust is an important pathway for humans. Airborne MNPs pose health risks to plants, animals, and humans. Atmospheric MNPs can enter organism bodies via inhalation and subsequent deposition in the lungs, which triggers inflammation and other adverse health effects. MNPs could be eliminated through source reduction, policy/regulation, environmental awareness and education, biodegradable materials, bioremediation, and efficient air-filtration systems. To achieve a sustainable society, it is crucial to implement effective strategies for reducing the usage of single-use plastics (SUPs). Further, governments play a pivotal role in addressing the pressing issue of MNPs pollution and must establish viable solutions to tackle this significant challenge.

Do microbial decomposers find micro- and nanoplastics to be harmful stressors in the aquatic environment? A systematic review of in vitro toxicological research

Microbial decomposers (bacteria and fungi) are likely to interact with plastic particles introduced into natural systems, particularly micro- and nanoplastics (MNPs), exposing them to a variety of risks. In vitro testing has proven to be an accessible and viable method for gaining insights into how microbial decomposers behave individually and systemically toward MNPs. Recent advances have enhanced our understanding of MNP interactions with organisms, revealing the molecular foundations of adaptive responses as well as the biological impact and potential risks to MNPs. Despite widespread attention, this topic has not yet been reviewed. Here, we conducted a systematic review of the available research to critically assess and highlight the most recent advances in two major areas: (1) methods for in vitro evaluation of environmentally relevant microbial decomposers to MNPs; and (2) current understanding of the underlying toxicity mechanisms gained from in vitro assessments. We also addressed the key considerations throughout and proposed available opportunities in the field. Our analysis revealed that MNPs' toxicity has been studied in vitro either alone or in combination with other contaminants (e.g., antibiotics and metallic nanoparticles), with Escherichia coli and polystyrene particles receiving the most attention. Moreover, there were methodological differences in terms of MNP size, shape, polymer, surface characteristics, exposure period, and concentrations. A combination of methods, including growth-viability tests, biochemical assays, and omics profiling (metabolomics and transcriptomics), were employed to detect the effects of MNP exposure and explain its toxicity mechanism. The current literature suggests that the impacts of MNPs on microbial decomposers include alterations in the antioxidative system, gene expression levels and cell-membrane permeability and oxidative damage, all of which can be further influenced by MNPs interaction with other contaminants. This review will thus provide critical insights and up-to-date knowledge to assist novices and experts in promoting advancements and research.

Microplastics in the seagrass ecosystems: A critical review

Marine microplastic (MP) pollution represents a global environmental issue that has ignited considerable apprehension within the international community. Seagrass beds, which serve as nearshore marine ecosystems, have emerged as focal points of plastic and MP contamination due to the pronounced density of anthropogenic activities and the hydrological mitigating effects of submerged vegetation. Nevertheless, our comprehension of MPs within seagrass ecosystems remains constrained. In this study, we employed bibliometric analyses and comprehensive data exploration to summarize the historical progression of the development, pivotal areas of interest, and research deficiencies, followed by proposing future research directions for MP pollution in seagrass beds. The 37 selected papers were sourced from the Web of Science Core Collection scientific database as of December 31st, 2022. Based on the current evaluation, MPs are ubiquitously discovered within seagrass canopies, sediments, and marine organisms, while less than 15 % of seagrass species worldwide have been investigated. Moreover, methodological inconsistencies in sampling, processing and visualization between studies hindered the fusion and comparison of data. MPs in upper sediments and seagrass blades were the most widely investigated, with an average abundance of 263.4 ± 309.2 n/kg and 0.09 ± 0.03 n/blade. In all environmental compartments, the prevalent forms of MPs comprise fibrous and fragmented particles, encompassing the dominant polymers such as polypropylene, polyethylene and polyethylene terephthalate. However, the source of MPs in seagrass beds based on MP characteristics and local hydrodynamics has not been comprehensively analyzed in previous studies. The evidence for MPs acting as pollutants and contaminant carries impacting the growth and decline of seagrass is also weak. Currently, the precise implications of MPs on submerged vegetation, organisms, and the broader seagrass ecosystem remain inconclusive. However, considering the persistent accumulation of MPs, it is imperative to explore the ecological hazards they may pose within the foreseeable future.

The comparative effects of visible light and UV-A radiation on the combined toxicity of P25 TiO2 nanoparticles and polystyrene microplastics on Chlorella sp

The ubiquitous presence of TiO2 nanoparticles (nTiO2) and microplastics (MPs) in marine ecosystems has raised serious concerns about their combined impact on marine biota. This study investigated the combined toxic effect of nTiO2 (1 mg/L) and NH2 and COOH surface functionalized polystyrene MPs (PSMPs) (2.5 and 10 mg/L) on Chlorella sp. All the experiments were carried out under both visible light and UV-A radiation conditions to elucidate the impact of light on the combined toxicity of these pollutants. Growth inhibition results indicated that pristine nTiO2 exhibited a more toxic effect (38%) under UV-A radiation when compared to visible light conditions (27%). However, no significant change in the growth inhibitory effects of pristine PSMPs was observed between visible light and UVA radiation conditions. The combined pollutants (nTiO2 + 10 mg/L PSMPs) under UV-A radiation exhibited more growth inhibition (nTiO2 + NH2 PSMPs 66%; nTiO2 + COOH PSMPs 50%) than under visible light conditions (nTiO2 + NH2 PSMPs 55%; TiO2 + COOH PSMPs 44%). Independent action modeling indicated that the mixture of nTiO2 with PSMPs (10 mg/L) exhibited an additive effect on the algal growth inhibition under both the light conditions. The photoactive nTiO2 promoted increased production of reactive oxygen species under UV-A exposure, resulting in cellular damage, lipid peroxidation, and impaired photosynthesis. The effects were more pronounced in case of the mixtures where PSMPs added to the oxidative stress. The toxic effects of the binary mixtures of nTiO2 and PSMPs were further confirmed through the field emission electron microscopy, revealing specific morphological abnormalities. This study provides valuable insights into the potential risks associated with the combination of nTiO2 and MPs in marine environments, considering the influence of environmentally relevant light conditions and the test medium.

Single and combined effects of CuSO4 and polyethylene microplastics on biochemical endpoints and physiological impacts on the narrow-clawed crayfish Pontastacusleptodactylus

This study investigated the toxicity of polyethylene microplastics (MPs; <0.02 mm) and CuSO4, alone and in combination, on the freshwater crayfish Pontastacus leptodactylus. In this study, the crayfish were exposed to PE-MPs (0.0, 0.5, and 1 mg L-1) and CuSO4·5H2O (0.0, 0.5, and 1 mg L-1) for a period of 28 days. Next, multi-biomarkers, including biochemical, immunological, and oxidative stress indicators were analyzed. Results showed that co-exposure to PE-MPs and CuSO4 resulted in increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and decreased alkaline phosphatase (ALP), butyrylcholinesterase (BChE), and gamma-glutamyl-transferase (GGT). Triglycerides, cholesterol, glucose, and albumin content also increased. Although no significant change was observed in lysozyme and phenoloxidase activities in crayfish co-exposed to 0.5 mg L-1 MPs and 0.5 mg L-1 CuSO4, their activities were significantly decreased in other experimental groups. Oxidative stress parameters in hepatopancreas indicated increased superoxide dismutase (SOD), glutathione peroxidase (GPx), and in malondialdehyde (MDA) levels, but decreased catalase (CAT), glucose 6-phosphate dehydrogenase (G6PDH), and cellular total antioxidant (TAC). Results showed that the sub-chronic toxicity of CuSO4 was confirmed. The study confirmed the toxicity of CuSO4 and found that higher concentrations led to more severe effects. Co-exposure to PE-MPs and CuSO4 primarily compromised the endpoints, showing increased toxicity when both pollutants were present in higher concentrations. The activities of POX, LYZ, ALP, GGT, LDH, and CAT were suppressed by both CuSO4 and MPs. However, a synergistic increase was observed in other measured biomarkers in crayfish co-exposed to CuSO4 and MPs.

Repair mechanism of Yishen Tongluo formula on mouse sperm DNA fragmentation caused by polystyrene microplastics

CONTEXT

Plastics can break down into millions of microplastic (MPs, < 5 mm) particles in the soil and ocean. These MPs can then affect the function of the reproductive system. There is currently no effective solution to this problem aside from traditional Chinese medicine. We have previously used Yishen Tongluo formula (YSTL) to treat sperm DNA damage caused by some toxic substances.

OBJECTIVE

To investigate the mechanism underlying the repair of mouse sperm DNA fragmentation caused by polystyrene microplastics by YSTL.

MATERIALS AND METHODS

An animal model of polystyrene microplastic (PS-MP)-induced sperm DNA damage was replicated by gavage of SPF ICR (CD1) mice PS-MPs at 1 mg/d and treated with YSTL at 11.89, 23.78 and 47.56 g/kg, respectively, for 60 days. The Sperm DNA fragmentation index (DFI) of each group was detected and compared. The target genes of YSTL identified by transcriptomic and proteomic analyses were validated by qRT-PCR and western blotting.

RESULTS

The DFI of the PS group (20.66%) was significantly higher than that of the control group (4.23%). The medium and high doses of the YSTL group (12.8% and 11.31%) exhibited a significant repairing effect. The most enriched pathway was PI3K/Akt. TBL1X, SPARC, hnRNP0, Map7D1, Eps8 and Mrpl27 were screened and SPARC was validated.

DISCUSSION AND CONCLUSIONS

The precise mechanism by which YSTL inhibits PD-MPs DNA damage may be associated with the PI3K/Akt pathway and SPARC. It provides a new direction for using traditional Chinese medicine to prevent and repair reproductive system injury caused by MPs.

Microplastics in marine invertebrates from the Red Sea Coast of Egypt: Abundance, composition, and risks

This study marked the first exploration of microplastics in marine invertebrates in the Red Sea Coast of Egypt. 110 individuals from 11 different species, including Bivalvia, Gastropoda, Echinoidea, and Holothuroidrea, were collected near a popular tourist destination. The average concentrations of microplastics varied among species, ranging from 8.2 to 136.5 items per individual or 0.2 to 18.1 items per gram of tissue wet weight, with 100 % occurrence. Bivalves had higher concentrations per gram of tissue compared to sediment dwellers and grazers, with Brachidontes pharaonis showing the highest levels. Actinopyga crassa, a sea cucumber, displayed the highest abundance per individual due to its large size and behavior. The identified plastic polymers suggested sources associated with tourism and maritime activities. The estimated human exposure to microplastics through bivalve consumption was minimal. Further research is needed to examine microplastics contamination in the Red Sea and its potential impacts on ecosystems and human well-being.

A standard analytical approach and establishing criteria for microplastic concentrations in wastewater, drinking water and tap water

The ubiquitous presence of microplastics (MPs) in natural water bodies reflects the global issue regarding these micropollutants. The main problem of MPs lies on the difficulty of removing these particles from water during wastewater and drinking water treatments. The release of MPs to the environment in treated wastewater contributed to the dispersion of these micropollutants, which enhances the harmful effect of MPs on fauna and flora. In addition, their presence in tap water entails a potential risk to human health since MPs can be directly consumed. The first step is being able to quantify and characterise these microparticles accurately. In this work, a comprehensive analysis on the presence of MPs in wastewater, drinking water and tap water has been conducted with emphasis on sampling methods, pre-treatment, MP size and analytical methods. Based on literature data, a standard experimental procedure has been proposed with the objective of recommending a methodology that allows the homogenisation of MP analysis in water samples. Finally, reported MP concentrations for influents and effluents of drinking and wastewater treatment plants and tap water have been analysed, in terms of abundance, ranges and average values, and a tentative classification of different waters based on their MP concentrations is proposed.

Polyethylene Microplastics Affected Survival Rate, Food Intake and Altered Oxidative Stress Parameters in Freshwater Snail Indoplanorbis exustus

Microplastics have a negative impact on aquatic ecosystems. Gastropod mollusks serve as bioindicators and are good model systems for ecotoxicological studies. To assess oxidative damage, we exposed the ram's horn snail, Indoplanorbis exustus, to various concentrations of low-density polyethylene microplastics (size range 8-100 µm). The main objectives were microplastics preparation, characterization, and examination of their effect on the essential organs of I. exustus. Scanning electron microscopy, fourier transform infrared spectroscopy and x-ray diffraction techniques confirmed the polymer type of laboratory prepared polyethylene microplastics. The LC50 value of microplastics for snails was calculated to be 872 mg/L after 96 h of exposure. We observed a significant elevation in superoxide dismutase, catalase and lipid peroxidation levels with increasing concentrations of microplastics. Microplastics exposure also affected protein content, total food intake and total weights. Moreover, snails failed to recover post-treatment. Snails collected from contaminated source of microplastics served as positive control for the study. Hence, we can conclude that microplastics cause overall impairment in the physiological parameters and show adverse effects on the freshwater snail, I. exustus.