Microplastics and associated contaminants in the aquatic environment: A review on their ecotoxicological effects, trophic transfer, and potential impacts to human health

Analysis of microplastic contamination and associated human health risks in Clarias gariepinus and Oreochromis niloticus from Kubanni Reservoir, Zaria Nigeria

Environmental safety has become a major concern in recent years due to the global increase in microplastic pollution. These ubiquitous, tiny, and potentially toxic plastic particles enter aquatic environments through weathering of larger plastics and the release of microbeads. Although numerous studies have focused on microplastic pollution in developed regions, information from developing countries remains limited. This study assessed the presence of MPs and associated oxidative stress responses in two commercial fish species, Clarias gariepinus (Catfish) and Oreochromis niloticus (Nile Tilapia), from Kubanni reservoir, Zaria, Nigeria, over six months spanning both the dry and rainy seasons. Fibers were identified as the most abundant MP particles, followed by fragments, films, and beads, in the order of fibers > fragments > films > beads. The highest fiber concentrations were recorded in the gills, with Clarias garipinus showing 11.5 MP items/individual and Oreochromis niloticus showing 22.5 MP items/individual. Black microplastics were predominant, and the most common ingested MP ranged from 1.0 to 2.0 mm. The primary polymers identified were polypropylene and polyethylene terephthalate. Evidence of oxidative stress and cellular damage was observed in the gills, liver, and dorsal muscles of both fish species, which correlated with MPs ingestion. According to recommendations from the European Food Safety Authority regarding fish consumption by children and adults, individuals consuming Clarias gariepinus and Oreochromis niloticus from the Kubanni reservoir may be exposed to between 70 and 700 MP items/organ. The risk associated with consuming MPs found in fish gills and guts was notably higher, posing significant concerns for human health. This study provides insights into microplastic contamination in commercially important fish from the Kubanni Reservoir and highlights the environmental and public health risks associated with consuming contaminated fish from this ecosystem.

Exploring micro(nano)plastics toxicity from an environmental management perspective: Zebrafish as a vital bridge for assessing potential human health risks

The pollution stemming from the unwarranted utilization and inadequate disposal of plastic products is undergoing rapid escalation. The problem of micro(nano)plastics (MNPs) pollution has recently garnered significant attention, and the issue of human exposure to MNPs cannot be disregarded. However, the present state of research concerning human exposure to MNPs remains in its early stages. The inherent uncertainty and variability associated with MNPs pose significant obstacles to conducting related studies. In order to enhance comprehension of the potential health risks associated with human exposure to MNPs, the utilization of zebrafish as an assessment tool was deemed appropriate. Zebrafish, as one of the most effective toxicological models, assume a significant role in both environmental monitoring and health modeling. This study provides a review of the effects of exposure to MNPs on zebrafish. The findings demonstrate that such exposure can elicit behavioral and physiological alterations in zebrafish, subsequently resulting in a range of toxic consequences. Simultaneously, this study conducts a comparative analysis of the effects of human and zebrafish exposure to MNPs in physiology, exposure environment, and toxicokinetic/toxicodynamic, leveraging the shared characteristics between zebrafish and humans to augment comprehension regarding human exposure to MNPs. Zebrafish model plays a key role in exploring gene expression in human homologous pathways caused by MNPs exposure, and strengthens the understanding of the risk of MNPs exposure. However, physiological, metabolic, and exposure circumstances limit its extrapolation to humans. Furthermore, the reference value and challenge associated with employing zebrafish as a model to discern human health hazards linked to MNPs are assessed, accompanied by suggestions for future research endeavors.

Quantitative tracking of the transformation of micro- and nanoplastics in simulated human body fluid

Micro- and nanoplastics (MNPs) are widespread in the environment and food, posing ingestion risks through various pathways. However, their transformation in human body fluids (SBFs), especially the formation of secondary nanoparticles (NPs), is not well understood due to inadequate quantification methods. This study proposed a robust method for quantifying eight common MNPs using pressurized liquid extraction (PLE) for pretreatment and pyrolysis gas chromatography-quadrupole time-of-flight mass spectrometry (Py-GC-QTOF-MS) for analysis. The method demonstrated high performance with recoveries over 90.9 % and a detection limit down to 0.01 mg/L. Most sample matrices did not interfere with MNP quantification, though poly(3-hydroxybutyrate) and polyethylene required background noise deduction. High recoveries in SBFs (>79.0 %) further confirmed the practicality of this method. Utilizing this method, it was found that only a few MPs were able to release secondary NPs within the simulated digestive system, with the maximum proportion of released NPs less than 2.1 %, suggesting a negligible health risk from secondary NPs. Besides, ester structure was found not to promote the formation of secondary NPs but did affect surface morphology and functional groups to a certain extent. We anticipate that this work will open opportunities for the health risk assessment of MNPs.

Polystyrene microplastics induce depression-like behavior in zebrafish via neuroinflammation and circadian rhythm disruption

Polystyrene microplastics (PS-MPs) are widespread pollutants in aquatic environments that accumulate in various organs, including the brain, raising concerns about their neurotoxic effects. This study exposed zebrafish to environmentally relevant concentrations (25 and 250 μg/L) of PS-MPs for 40 days to investigate their impact on neurobehavior and underlying mechanisms. Results revealed that PS-MPs induced depression-like behaviors in zebrafish, characterized by reduced exploration, decreased locomotor activity, and altered social interaction. Histological analyses of brain tissue demonstrated PS-MPs-induced neuropathological changes, including perinuclear vacuolation and reduced Nissl bodies. Additionally, PS-MPs triggered neuroinflammation, evidenced by upregulated pro-inflammatory cytokines (il-6, il-1β), and disrupted the circadian rhythm, leading to altered expression of key clock genes (per1b, per2, per3) and cryptochrome genes (cry1a, cry2). Furthermore, PS-MPs exposure significantly altered neurotransmitter levels, decreasing dopamine, serotonin, norepinephrine, acetylcholine, tyrosine, and tryptophan. In vitro experiments using HMC3 microglia cells confirmed that PS-MPs induced microglial activation, morphological changes, and dysregulated gene expression related to inflammation and circadian rhythm. These findings provide compelling evidence that PS-MPs induce depression-like behaviors in zebrafish through mechanisms involving neuroinflammation, circadian rhythm disruption, and neurotransmitter imbalances, highlighting the potential ecological risks of PS-MPs and contributing to our understanding of the neurotoxicity of microplastics.

Combined toxic effects of polystyrene microplastic and benzophenone-4 on the bioaccumulation, feeding, growth, and reproduction of Daphniamagna

The potential toxicity of microplastics (MPs) and UV filter Benzophenone-4 (BP4) to aquatic organisms has caused widespread concern among the public. However, the combined effects of MPs and BP4 on aquatic organisms are not well understood. This study sought to examine the combined impacts of 10 μg/L BP4, 1 mg/L Polystyrene (PS, 10 μm), and a mixture of both on the feeding, behavior, growth, and reproduction of Daphnia magna (D. magna) over a period of 21 days. The results showed that the combined exposure led to a reciprocal facilitation of bioaccumulation, along with a decrease in the second antenna beats frequency in D. magna. While the co-exposure did not change the body size or growth rate of D. magna, it did affect their feeding efficiency, leading to a decrease in Chlorella ingestion within a 24-h period. Furthermore, there was a high occurrence of malformations in two generations of D. magna exposed to BP4 and PS. The combined exposure also negatively affected reproductive parameters, such as the cumulative number of neonates and the days of first brood, suggesting a decline in overall reproductive success possibly due to feeding inhibition, with available energy potentially being redistributed between reproduction and growth in the daphnids. Co-exposure to BP4 and PS also led to elevated levels of Reactive Oxygen Species (ROS), Malonydialdehyde (MDA), and Glutathione (GSH) levels, as well as mRNA levels related to reproduction, growth, and detoxification in D. magna. Overall, this study delved into the consequences of BP4 and PS on bioaccumulation, feeding, behavior, growth, and reproduction, demonstrating that simultaneous exposure to BP4 and PS could pose a synergistic ecological hazard, potentially threatening aquatic organisms. These findings are critical and should be taken into account for accurate environmental risk assessments.

Microplastics in freshwater food chains: Priority list based on identification of oxidative stress response characteristic

Exogenous exposure to high concentrations of microplastics (MPs) cause oxidative damage to freshwater food chains (FFCs). Thus, the patterns and mechanisms of oxidative stress responses (OSRs) induced by MPs in FFC organisms were investigated using theoretical simulation methods. Results showed an increasing (reduced) OSR was found in lower trophic levels (higher trophic levels). Besides, polycarbonate (polyvinyl chloride) causes the most (least) significant OSRs in FFC organisms, respectively. The impacts of MP additives were also analyzed using the full factorial experimental design, revealing flame retardants significantly influence oxidative stress variability. A constructive solution of "restriction-control-focus" is proposed for different types of MPs by the coefficient of variation-corrected CRITIC and the nested mean classification method. The mechanism analysis revealed a positive correlation between protein secondary structure orderliness and OSRs. Proteins in organisms that contain a high proportion of hydrophobic non-polar amino acids are more likely to bind to MP and enhance OSRs. This is the first study assessing the OSR patterns and ecological risks of MPs and their additives in FFCs with a proposed priority list, providing theoretical support for risk assessments and management strategies in freshwater environments.

UV-B radiation aging changed the environmental behavior of polystyrene micro-/nanoplastics-adsorption kinetics of BDE-47, plankton toxicities and joint toxicities with BDE-47

UV-B radiation acts as an important environmental factor for aging micro-/nanoplastics (MNPs) in the marine environments, while the effect of aged MNPs on plankton is lacking specific research. Referencing to the UV-B radiation intensity in natural environments (2.29 W·m-2), we chose the floating polystyrene (PS) MNPs (50 nm, 1 µm) as the research target in this study. The results indicated that UV-B radiation aging for 30 days led to a rougher surface, increased SBET, increased hydrophobicity, and decreased negative charges of PS MNPs. Correspondingly, aged MNPs increased their adsorption abilities for 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), especially for the initial stage. After UV-B radiation aging processes, the individual toxicities of the two sized MNPs on Thalassiosira pseudonana and Brachionus plicatilis both increased, while their joint toxicities with BDE-47 decreased on T. pseudonana but increased on B. plicatilis. The changes in toxicity were more pronounced in 1 µm PS MNPs under air-aged conditions. This study provided the data basis for evaluating the changes of MNPs environmental behaviors under UV-B radiation in the marine environments, with important ecological significance.

Pollution characterization and multi-index ecological risk assessment of microplastics in urban rivers from a Chinese megacity

Currently, a comprehensive understanding of the pollution risks of microplastics (MPs) in urban river ecosystems is still lacking. This study investigated the spatial distribution and morphological characteristics of MPs in surface waters of major rivers in Shenzhen, a megacity in China, using laser direct infrared (LDIR) imaging. A promisingly comprehensive risk assessment method, MultiMP, was first proposed in this study, taking into account the multidimensional characteristics of MPs including abundance, size, shapes, and polymer types. The results showed that MPs were widespread and highly heterogeneous, and the abundance of MPs ranged from 38 to 18380 particles/L, with an average of 2305 particles/L. Morphologically, polyamide (PA) (average 53.7 %), 30-50 µm (73.8 %), and pellet (65.7 %) were the predominant MPs types. Driving factors analyses revealed geographical distance, salinity, water temperature, and total nitrogen had relatively higher impacts on the abundance and morphology of MPs. The MultiMP results indicated that most of the river sampling sites and five major basins in Shenzhen were at moderate to high-risk levels. Polymer type and abundance had a relatively high impact on the environmental risk of MPs in the region. These findings contribute to improving the insights and management of the MPs pollution risks in megacity water bodies.

Deep learning-powered efficient characterization and quantification of microplastics

Characterizing and quantifying microplastics (MPs) are time-consuming and labor-intensive tasks traditionally. This paper presents an artificial intelligence (AI) framework aiming to automate these tasks by integrating computer vision and deep learning techniques. The approach leverages Fourier Transform Infrared (FTIR) spectra and visual images. Primary novelties of this research involve the development of: (1) an AI framework integrating efforts of data processing, analytics, visualization, and human-computer interaction; (2) a method for transforming FTIR data into contour images; (3) data augmentation strategies for resolving data scarcity and imbalance issues; (4) deep learning models for identifying MPs; (5) computer vision algorithms for quantifying MPs; and (6) an engineer-friendly graphic user interface (GUI) for enhancing data accessibility. The AI framework has been applied to polyethylene, polypropylene, polystyrene, polyamide, ethylene-vinyl acetate, and cellulose acetate. Results confirmed the efficacy of the framework, exhibiting high accuracy scores in classification (98 %), segmentation (99 %), and quantification (96 %) tasks. This research advances the capability of automatic assessment of MPs.

Addressing data gaps in deriving aquatic life ambient water quality criteria for contaminants of emerging concern: Challenges and the potential of in silico methods

The international community is becoming increasingly aware of the threats posed by contaminants of emerging concern (CECs) for ecological security. Aquatic life ambient water quality criteria (WQC) are essential for the formulation of risk prevention and control strategies for pollutants by regulatory agencies. Accordingly, we systematically evaluated the current status of WQC development for typical CECs through literature review. The results revealed substantial disparities in the WQC for the same chemical, with the coefficients of variation for all CECs exceeding 0.3. The reliance on low-quality data, high-uncertainty derivation methods, and limited species diversity highlights a substantial data gap. Newly developed in silico methods, with potential to predict the toxicity of untested chemicals, species, and conditions, were classified and integrated into a traditional WQC derivation framework to address the data gap for CECs. However, several challenges remain before such methods can achieve widespread acceptance. These include unstable model performance, the inability to predict chronic toxicity, undefined model applicability, difficulties in specifying toxicity effects and predicting toxicity for certain key species. Future research should prioritize: 1) improving model accuracy by developing specialized models trained with relevant, chemical-specific data or integrating chemical-related features into interspecies models; 2) enhancing species generalizability by developing multispecies models; 3) facilitating the derivation of environmentally relevant WQC by incorporating condition-related features into models; and 4) improving the regulatory acceptability of in silico methods by evaluating the reliability of "black-box" models.

Distribution and co-occurrence of microplastics and co-existing pollutants in bottom water and sediment of the East China Sea

Microplastics (MPs) contamination in marine environment has been an emerging issue worldwide, notably due to the potential ecological risks of MPs with co-existing environmental contaminants and released toxic plastic additives. To verify the co-occurrence characteristics of MPs and co-existing pollutants in the benthic boundary layer (BBL), the distribution characteristics of MPs, and selected heavy metals (HMs) and halogenated flame retardants (Polybrominated diphenyl ethers, PBDEs, and Dechlorane Plus) in the bottom water and sediment were comprehensively investigated in the East China Sea (ECS). The sampling sites were selected along the coast of ECS, where might be significantly affected by terrigenous inputs and anthropogenic sources. MPs were abundant in the bottom water (62.8-480.2 items/L) and sediment (80.1-1346.7 items/kg d.w.) with polyester, polyethylene, and polypropylene being as the most abundant types and characterized as fiber/line, particle size 200-500 μm, and transparent/white. The abundance and characteristics of MPs demonstrated strong correlations within the bottom water and sediment, which might be due to the frequent exchange of materials. In addition, the abundance of MPs was significantly positively correlated with HMs (Cd, Cr, Pb) in the bottom water and PBDEs in sediment, respectively. According to the scanning electron microscopy/energy dispersive X-ray spectrometry analysis, MPs might act as carriers to transport and co-sediment the co-existing pollutants in water, and physically adsorb or chemically bind with pollutants in sediment. These results could help to elucidate the sources, migration, and fate, and verify the occurrence and potential risks of MPs and their co-existing pollutants in BBL, thus realize the management and control of MPs contamination in marine.

Uptake, removal and trophic transfer of fluorescent polyethylene microplastics by freshwater model organisms: the impact of particle size and food availability

As an emerging contaminant, microplastics (MPs) are widely distributed in freshwater ecosystems and pose potential threats to aquatic organisms, attracting significant attention from both the scientific community and the general public. However, there is still uncertainty regarding the mechanisms of MPs transfer within aquatic biota and how particle size and food availability influence their transport patterns. In this study, zebrafish (Danio rerio) were selected as a model organism to investigate the uptake and elimination of fluorescent polyethylene (PE) MPs under different exposure scenarios (waterborne or trophic transfer, with or without food) and varying particle sizes (ranging from 10-300 μm at concentrations of 0.1, 2, and 300 mg/L). Additionally, water fleas (Daphnia magna) were provided as prey for the fish. The dynamic accumulation of PE-MPs sized between 10-20 μm at a concentration of 25 mg/L by daphnia was also determined along with its impact on animal feeding behavior. The results demonstrated that both organisms were capable of ingesting PE-MPs during exposures lasting up to 24 hours for daphnia and up to 72 hours for zebrafish. Furthermore, rapid elimination rates were observed within just 30 minutes for daphnia and between 6-12 hours for zebrafish. The presence of food reduced MPs uptake and removal by daphnia but significantly increased MP elimination by fish. Zebrafish showed a preference for ingesting larger-sized MPs that they could easily recognize; however, trophic transfer from daphnia to fish was found to be the primary route of ingestion specifically for PE-MPs sized between 10-20 μm. The findings suggest that while fish directly ingest fewer invisible MPs from the water column, they still accumulate these particles through predation on contaminated prey organisms. Therefore, it is imperative to prioritize the ecological risks associated with the transfer of MPs from zooplankton to fish.

Characterization and ecological risks of microplastics in urban road runoff

Microplastics (MPs) deposited on urban roads are often flushed into water bodies via drainage systems without treatment, and MP concentrations in the initial road runoff may be particularly high. Yet, there is only a limited understanding of the characteristics, dynamics, and impacts of MPs in urban road runoff. In this study, stormwater and rainwater samples were collected from seven different locations in Hong Kong across 11 rainfall events between February 2021 and September 2022. Characteristics of MPs in the collected samples were analyzed in detail, along with the dynamics of MP concentration in rainfall events, possible influencing factors, and ecological risks. The results show that MP concentration in the initial road runoff is particularly high during a rainfall episode. Overall, the median MP abundance in the collected runoff samples (185 particles/L) was 4.6 times higher than that in rainwater (40 particles/L). The most common polymers identified were polyethylene, polypropylene, and polystyrene, with fragments being the dominant shape. Over 60 % of MP sizes were smaller than 300 μm in the runoff samples. Additionally, risk assessments based on the Polymer Risk Index (PRI) classified most road sites in pollution classes II to III (PRI = 13.3-138.0), indicating moderate to high ecological risks. It appears that MP abundance in the initial runoff was significantly influenced by seasonal changes. These findings highlight urban roads as a major source of MP pollution in stormwater runoff and emphasize the importance of addressing the initial runoff in pollution control.

Global patterns of lake microplastic pollution: Insights from regional human development levels

Microplastics have emerged as a pervasive pollutant across various environmental media. Nevertheless, our understanding of their occurrence, sources, and drivers in global lakes still needs to be completed due to limited data. This study compiled data from 117 studies (2016-May 2024) on microplastic contamination in lake surface water and sediment, encompassing surface water samples in 351 lakes and lake sediment samples in 200 lakes across 43 countries. Using meta-analysis and statistical methods, the study reveals significant regional variability in microplastic pollution, with concentrations ranging from 0.09 to 130,000 items/m3 in surface water and from 5.41 to 18,100 items/kg in sediment. Most microplastics were under 1 mm in particle size, accounting for approximately 79 % of lake surface water and 76 % of sediment. Transparent and blue microplastics were the most common, constituting 34 % and 21 % of lake surface water and 28 % and 18 % of sediment, respectively. Fibers were the dominant shape, representing 47 % of lake surface water and 48 % of sediment. The primary identified polymer types were polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Countries like India, Pakistan, and China had higher contamination levels. Positive correlations were found between microplastic abundance in surface water and factors like human footprint index (r = 0.29, p < 0.01), precipitation (r = 0.21, p < 0.05), and net surface solar radiation (r = 0.43, p < 0.001). In contrast, negative correlations were observed with the human development index (r = -0.61, p < 0.01) and wind speed (r = -0.42, p < 0.001). In sediment, microplastics abundance correlated positively with the human footprint index (r = 0.45, p < 0.001). This study underscores the variability in microplastic pollution in global lakes and the role of human activities and environmental factors, offering a valuable reference for future research.

Species-specific accumulation of microplastics in different bird species from South China: A comprehensive analysis

Microplastics are widespread in many bird species, but the inter-specific variations of microplastic contamination are still unclear. The present study measured microplastics in 24 bird species from South China and investigated the impacts of bird physiological and ecological traits on microplastic contamination. The median abundances of microplastics ranged between 5-167 particles per individual or 0.023-3.58 particles per g body weight. Approximately 60 % of microplastics were within the size range 20-50 µm, with the primary polymer types of polypropylene (PP) and polyethylene terephthalate (PET). There was no significant correlation between microplastic abundances and bird body weights and trophic levels (δ15N) in different bird species. Insectivorous birds had significantly higher abundances of microplastics smaller than 0.1 mm than granivorous, piscivorous, and carnivorous birds (p < 0.01), which was further supported by the meta-analysis of microplastic contamination in birds. On contrary, meta-analysis results indicate that piscivorous birds tend to accumulate larger microplastics (> 1 mm) than other bird species. Microplastic contamination in different bird species was more influenced by diet source rather than trophic level and body weight. Potential ecotoxicological risks were observed for most insectivorous species in the preliminary risk assessment. Particular concern should be paid on insectivorous birds, which have been scarcely studied for microplastics but were at high exposure risks of microplastics among bird species.

Microplastics occurrence in sea cucumbers and impacts on sea cucumbers & human health: A systematic review

Microplastics (MPs) are a developing concern in marine environments, with scientists concentrating more on their effects on various creatures. Sea cucumbers (SCs), as suspension and deposit feeders, are expected to be exposed to and consume MPs in their habitat. The purpose of this methodical review is to gather and integrate accessible research on the presence and effects of MPs on SCs. A systematic search of relevant databases yielded relevant papers exploring the occurrence of MPs in SC habitats as well as the possible effects of MP intake on SCs. Bibliometric analysis was also conducted to collect and analyze a large volume of data. Then the papers were sorted (a total of 249) related to the occurrence and effects of MPs in SCs. Finally, targeted data were collected from the articles for the study. The review emphasizes the ubiquity of MPs in SC ecosystems, citing studies that found high quantities in coastal areas and sediment. MPs have a variety of effects on SCs, with some studies indicating that they lower eating efficiency, affect behavior, and cause tissue damage. However, there is still no unanimity on the overall effects of MP exposure on SCs. This review gives a complete summary of the present state of information about the incidence and impact of MPs on SCs, highlighting the need for additional study in this area. Understanding the possible dangers of MPs on SCs is critical for the survival of these ecologically significant creatures.

Enrichment characteristics of microplastics in Antarctic benthic and pelagic fish and krill near the Antarctic Peninsula

Global microplastic pollution has garnered widespread attention from researchers both domestically and internationally. However, compared to other regions worldwide, little is known about microplastic pollution in the marine ecosystems of the Antarctic region. This study investigated the abundance and characteristics of microplastics (MPs) in the gills and intestines of 15 species of Antarctic fish and Antarctic krill (Euphausia superba). The results indicate that the abundance of MPs in Antarctic fish and E. superba ranged from 0.625 to 2.0 items/individual and 0.17 to 0.27 items/individual, with mean abundances of 0.93 ± 0.96 items/individual and 0.23 ± 0.44 items/individual, respectively. Antarctic fish ingested significantly more MPs than E. superba. There was no significant difference in the abundance of MPs between the gills and intestines of Antarctic fish. However, the quantity of pellet-shaped MPs in the gills was significantly higher than in the intestines. The depth of fish habitat influenced the quantity and size of MPs in their bodies, with benthic fish ingesting significantly fewer MPs than pelagic fish. Pelagic fish ingested significantly more MPs sized 1-5 mm than benthic fish. Additionally, analysis of the characteristics of MPs revealed that fiber-shaped MPs were predominant in shape, with sizes generally smaller than 0.25 mm and 0.25-0.5 mm. The predominant colors of MPs were transparent, red, and black, while the main materials were polypropylene (PP), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC). Compared to organisms from other regions, the levels of MPs in Antarctic fish and E. superba were relatively low. This study contributes to a better understanding of the extent of MP pollution in Antarctic fish and E. superba, aiding human efforts to mitigate its impact on the environment.

Microplastics and nanoplastics in soil: Sources, impacts, and solutions for soil health and environmental sustainability

The present review discusses the growing concern of microplastics (MPs) and nanoplastics (NPs) in soil, together with their sources, concentration, distribution, and impact on soil microorganisms, human health, and ecosystems. MPs and NPs can enter the soil through various pathways, such as agricultural activities, sewage sludge application, and atmospheric deposition. Once in the soil, they can accumulate in the upper layers and affect soil structure, water retention, and nutrient availability. The presence of MPs and NPs in soil can also have ecological consequences, acting as carriers for pollutants and contaminants, such as heavy metals and persistent organic pollutants. Additionally, the leaching of chemicals and additives from MPs and NPs can pose public health risks through the food web and groundwater contamination. The detection and analyses of MPs and NPs in soil can be challenging, and methods involve spectroscopic and microscopy techniques, such as Fourier-transform infrared spectroscopy and scanning electron microscopy. To mitigate the presence and effects of MPs and NPs in soil, it is essential to reduce plastic waste production, improve waste management practices, and adopt sustainable agricultural practices. Effective mitigation measures include implementing stricter regulations on plastic use, promoting biodegradable alternatives, and enhancing recycling infrastructure. Additionally, soil amendments, such as biochar and compost, can help immobilize MPs and NPs, reducing their mobility and bioavailability. This review article aims to provide a comprehensive understanding of these emerging environmental issues and identify potential solutions to alleviate their impact on soil health, ecosystem functioning, and community health.

Appraisal of microplastic pollution and its related risks for urban indoor environment in Bangladesh using machine learning and diverse risk evolution indices

The widespread presence of Microplastics (MPs) is increasing in the indoor environment due to increasing annual plastic usage, which is becoming a global threat to human health. Therefore, this is the first research in Bangladesh to identify, and characterize, MP pollution and its allied threats to human health in the indoor urban environment, where 80 household dust samples were collected from the whole study area. The presence of MPs in household dust of the urban indoor environment was 25.8 ± 6.43 particles/g with a significant variety, whereas the fiber shape (73%), 0.5-1.00 mm ranged MPs size (58%), blue color (21%), and polystyrene polymer (34%) was the most ubiquitous MPs category. The pollution load index (1.61-2.96) indicated significant pollution due to the high abundance of MPs. Besides, other risks evaluating indices including contamination factor (1.00-3.51), and Nemerow pollution index (1.60-3.51) represent moderate to high MP-induced pollution. The polymer hazard index (119.54 ± 70.34) indicated significant risks for the selected polymers to the indoor environment living inhabitants. Machine learning approaches, especially random forest and support random vector machine were effective in predicting the number of MPs, where EC, salinity, pH, OC, and texture classes acted as controlling factors. Children and adults might be ingesting 4.12 ± 1.01 and 2.27 ± 0.57 particles/day through the ingestion exposure route, which has significant health effects. Polymer-associated lifetime cancer risk assessment results show that there are moderate risks for both adults and children, but children tend to be more susceptible to MP risks. The overall study found that Dhaka was the most severely MPs induced risky division among the others. This study reveals that high quantities of MPs in indoor environments could pose a serious health hazard' to different exposure groups.

Microplastics exacerbate tissue damage and promote carcinogenesis following liver infection in mice

Cancer is a leading cause of death worldwide, posing a substantial threat to human well-being. Microplastics (MPs) exposure can harm human health and the carcinogenicity of MP remains uncertain. In this study, we investigated carcinogenesis by MPs exposure. We observed MP significantly exacerbated hepatic injury in infectious conditions. In addition, cancer-related p53 and p21 signals are activated by MPs. Analysis of the liver transcriptomic landscape uncovered a noteworthy intensification of the carcinogenesis pathway by MPs compared with pre-infection. The transcription factor SALL2 could act as an oncogenic promoter in the promotion of cancer regulated by MPs. Further, big data analysis presents the correlation between MPs pollution and human hepatocellular carcinoma. This work revealed a toxic amplification effect of the non-bioactive MPs on the bioactive pathogens. This finding provides new insight into understanding the potential toxicity of the MPs.

Sight of Aged Microplastics Adsorbing Heavy Metal Exacerbated Intestinal Injury: A Mechanistic Study of Autophagy-Mediated Toxicity Response

Contaminant-bearing polystyrene microplastics (PSMPs) may exert significantly different toxicity profiles from their contaminant-free counterparts, with the role of PSMPs in promoting contaminant uptake being recognized. However, studies investigating the environmentally relevant exposure and toxic mechanisms of aged PSMPs binding to Cr are limited. Here, we show that loading of chromium (Cr) markedly alters the physicochemical properties and toxicological profiles of aged PSMPs. Specifically, Cr-bearing aged PSMPs induced severe body weight loss, oxidative stress (OS), autophagy, intestinal barrier injury, inflammation-pyroptosis response, and enteropathogen invasion in mice. Mechanistic investigations revealed that PSMPs@Cr exacerbated the OS, resulting in intestinal barrier damage and inflammation-pyroptosis response via overactivated Notch signaling and autophagy/cathepsin B/IL-1β pathway, respectively, which ultimately elevated mortality related to bacterial pathogen infection. In vitro experiments confirmed that autophagy-mediated reactive oxygen species (ROS) overproduction resulted in severe pyroptosis and impaired intestinal stem cells differentiation alongside the overactivation of Notch signaling in PSMPs@Cr-exposed organoids. Overall, our findings provide an insight into autophagy-modulated ROS overproduction within the acidic environment of autophagosomes, accelerating the release of free Cr from PSMPs@Cr and inducing secondary OS, revealing that PSMPs@Cr is a stable hazard material that induces intestinal injury. These findings provided a potential therapeutic target for environmental MPs pollution caused intestinal disease in patients.

Microplastic contamination in the agri-food chain: The case of honeybees and beehive products

Microplastics, MPs, plastic fragments with a dimension lower than 5 mm, and microfibers, MFs, synthetic and natural/artificial fibrous fragments with a diameter lower than 50 μm, are ubiquitous pollutants identified in different environmental compartments. In this work the occurrence of MPs and MFs on honeybees, Apis mellifera, and beehive products was evaluated, using Fourier transform infrared microspectroscopy, confirming that MPs and MFs are widely present as air contaminants in all the apiary's areas (high and low urbanized areas) in Southern Italy. Results indicated that independently from the site, both honeybees and honey samples, are contaminated by MFs with non-natural color. The majority of MFs were of natural origin followed by artificial MFs and synthetic MFs. Moreover, the chemical composition of MFs isolated from honeybees reflect that used in synthetic fabrics, leading to the hypothesis that they are released from textile to air where are captured by bees. Results highlight that MFs represent a class of ubiquitous airborne anthropogenic pollutants. The identification of polytetrafluoroethylene, PTFE, MPs in honeybees confirm the recent findings that PTFE MPs are diffuse soil and air contaminants while the identification of polyethylene, PE, based MPs in honey samples, from low density urban sites, could be correlated to the large use of PE in agriculture. In the honey samples, also polycaprolactone, PCL, MPs were identified, mainly in high density urban sites, confirming that biodegradable materials could be further pollutants in the environments. The results indicate that honeybees are contaminated by MPs and MFs during their flights or picking up from the hive components, flowers, from other nest mates, from the clothes of the beekeeper, among others and some of them could be transferred to honey samples that could be also affected by soil contamination.

A comprehensive review of urban microplastic pollution sources, environment and human health impacts, and regulatory efforts

Microplastic (MP) pollution in urban environments is a pervasive and complex problem with significant environmental and human health implications. Although studies have been conducted on MP pollution in urban environments, there are still research gaps in understanding the exact sources, regulation, and impact of urban MP on the environment and public health. Therefore, the goal of this study is to provide a comprehensive overview of the complex pathways, harmful effects, and regulatory efforts of urban MP pollution. It discusses the research challenges and suggests future directions for addressing MPs related to environmental issues in urban settings. In this study, original research papers published from 2010 to 2024 across ten database categories, including PubMed, Google Scholar, Scopus, and Web of Science, were selected and reviewed to improve our understanding of urban MP pollution. The analysis revealed multifaceted sources of MPs, including surface runoff, wastewater discharge, atmospheric deposition, and biological interactions, which contribute to the contamination of aquatic and terrestrial ecosystems. MPs pose a threat to marine and terrestrial life, freshwater organisms, soil health, plant communities, and human health through ingestion, inhalation, and dermal exposure. Current regulatory measures for MP pollution include improved waste management, upgraded wastewater treatment, stormwater management, product innovation, public awareness campaigns, and community engagement. Despite these regulatory measures, several challenges such as; the absence of standardized MPs testing methods, MPs enter into the environment through a multitude of sources and pathways, countries struggle in balancing trade interests with environmental concerns have hindered effective policy implementation and enforcement. Addressing MP pollution in urban environments is essential for preserving ecosystems, safeguarding public health, and advancing sustainable development. Interdisciplinary collaboration, innovative research, stringent regulations, and public participation are vital for mitigating this critical issue and ensuring a cleaner and healthier future for urban environments and the planet.

In Vitro and In Vivo Genotoxicity of Polystyrene Microplastics: Evaluation of a Possible Synergistic Action with Bisphenol A

The ubiquitous presence of plastics represents a global threat for all ecosystems and human health. In this study, we evaluated, in vitro and in vivo, the genotoxic potential of different concentrations of polystyrene microplastics (PS-MPs) and their possible synergistic interactions with bisphenol-A (BPA). For the in vitro and the in vivo assays, we used human lymphocytes and hemocytes from Lymnaea stagnalis, respectively. The genomic damage was evaluated by the micronucleus assay, and differences in eggs laid and growth of L. stagnalis were also evaluated. In human lymphocytes, PS-MPs alone at the concentration of 200 μg/mL and in association with BPA 0.100 µg/mL significantly increased the frequencies of micronuclei and nuclear buds, indicating a possible in vitro genotoxic additive action of these two compounds. Vice versa, PS-MPs did not result in genotoxicity in hemocytes. Our results indicated that PS-MPs have genotoxic properties only in vitro and at a concentration of 200 µg/mL; moreover, this compound could intensify the genomic damage when tested with BPA, indicating possible cumulative effects. Finally, PS significantly reduced the growth and the number of laid eggs in L. stagnalis.

Visual observation of polystyrene nano-plastics in grape seedlings of Thompson Seedless and assessing their effects via transcriptomics and metabolomics

Micro/nano-plastics (MNPs) are emerging non-point source pollutants that have garnered increasing attention owing to their threat to ecosystems. Studies on the effects of MNPs on horticultural crops are scarce. Specifically, whether MNPs can be absorbed and transported by grapevines have not been reported. To fill this gap, we added polystyrene nanoplastics (PS-NPs, 100 nm) to a hydroponic environment and observed their distribution in grape seedlings of Thompson Seedless (TS, Vitis vinifera L.). After 15 d of exposure, plastic nanospheres were detected on the cell walls of the roots, stems, and leaves using confocal microscopy and scanning electron microscopy. This indicated that PS-NPs can also be absorbed by the root system through the epidermis-cortex interface in grapevines and transported upward along the xylem conduit. Furthermore, we analyzed the molecular response mechanisms of TS grapes to the PS-NPs. Through the measurement of relevant indicators and combined omics analysis, we found that plant hormone signal transduction, flavonoid and flavonol biosynthesis, phenylpropanoid biosynthesis, and MAPK signaling pathway biosynthesis played crucial roles in its response to PS-NPs. The results not only revealed the potential risk of MNPs being absorbed by grapevines and eventually entering the food chain but also provided valuable scientific evidence and data for the assessment of plant health and ecological risk.

Polystyrene nanoplastics alter intestinal toxicity of 2,4-DTBP in a sex-dependent manner in zebrafish (Danio rerio)

Nanoplastics (NPs) and 2,4-di-tert-butylphenol (2,4-DTBP) are ubiquitous emerging environmental contaminants detected in aquatic environment. While the intestinal toxicity of 2,4-DTBP alone has been studied, its combined effects with NPs remain unclear. Herein, adult zebrafish were exposed to 80 nm polystyrene nanoplastics (PS-NPs) or/ and 2,4-DTBP for 28 days. With co-exposure of PS-NPs, impact of 2,4-DTBP on feeding capacity and intestinal histopathology was enhanced in males while attenuated in females. Addition of PS-NPs significantly decreased the uptake of 2,4-DTBP in females, while the intestinal concentrations of 2,4-DTBP were not different between the sexes in co-exposure groups. Furthermore, lower intestinal pH and higher contents of digestive enzymes were detected in male fish, while bile acid was significantly increased in co-exposed females. In addition, co-exposure of PS-NPs stimulated female fish to remodel microbial composition to potentially enhance xenobiotics degradation, while negative Aeromonas aggravated inflammation in males. These results indicated that in the presence of PS-NPs, the gut microenvironment in females can facilitate the detoxification of 2,4-DTBP, while exaggerating toxiciy in males. Overall, this study demonstrates that toxicological outcomes of NPs-chemical mixtures may be modified by sex-specific physiology and microbiota composition, furthering understanding for environmental risk assessment and management of aquatic environments.

Polystyrene nanoparticles with different particle sizes cause autophagy by ROS/ERS/FOXO1 axis in the Cyprinus carpio kidney affecting immunological function

Microplastic pollution poses challenges for ecosystems worldwide, and nanoplastics (NPs, 1-1000 nm) have been identified as persistent pollutants. However, although some studies have described the hazards of NPs to aquatic organisms, the toxicological processes of NPs in the common carp kidney and the biotoxicity of differently sized NPs remain unclear. In this study, we used juvenile common carp as an in vivo model that were constantly exposed to freshwater at 1000 μg/L polystyrene nanoparticle (PSNP) concentrations (50, 100, and 400 nm) for 28 days. Simultaneously, we constructed an in vitro model utilizing grass fish kidney cells (CIK) to study the toxicological effects of PSNPs of various sizes. We performed RT-PCR and Western blot assays on the genes involved in FOXO1, HMGB1, HIF-1α, endoplasmic reticulum stress, autophagy, and immunoreaction. According to these results, exposure to PSNPs increased reactive oxygen species (ROS) levels, and the carp kidneys experienced endoplasmic reticulum stress. Additionally, PSNPs promoted renal autophagy by activating the ROS/ERS/FOXO1 (ERS: endoplasmic reticulum stress) pathway, and it affected immunological function by stimulating the ROS/HMGB1/HIF-1α signaling pathway. This study provides new insights into the contamination hazards of NPs in freshwater environments, as well as the harm they pose to the human living environments. The relationship between particle size and the degree of damage caused by PSNPs to organisms is a potential future research direction.

First Evidence of Microplastic Ingestion by Riverine Fish From the Freshwater of Northwest Peninsular Malaysia

In a baseline study, we investigated microplastic contamination in fish from the Pinang and Kerian Rivers in Northwest Peninsular Malaysia. In recognition of the growing concern over microplastic pollution in aquatic environments, we aimed to assess the abundance and characteristics of microplastics ingested by various fish species. Fish samples were collected from local fishermen, followed by a digestion process using 10% potassium hydroxide (KOH). Microplastics were isolated and analyzed through visual examination and attenuated total reflectance Fourier transform infrared spectroscopy. The results revealed a high prevalence of microplastics, with Johnius borneensis and Oreochromis sp. exhibiting the highest abundance, averaging 48.6 and 42.8 microplastics/g, respectively. The predominant shapes were fibers (55.6%) and fragments (25.9%), with colors primarily transparent (48.19%) and black (30.12%). Our results indicate significant contamination levels in freshwater fish, emphasizing the need for further research and effective mitigation strategies. These findings provide crucial baseline data on microplastics in Malaysian freshwater ecosystems. Environ Toxicol Chem 2024;43:2189-2198. © 2024 SETAC.

Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China

BACKGROUND

Microplastics are environmental pollutants detected in various human organs and tissues. These particles originate from multiple sources including the degradation of larger plastic items and the intentional inclusion in consumer goods. Potential risks for human health resulting from microplastics exposure have also been reported. However, the distribution in the male reproductive system and its effect remains largely unknown. This study aims to investigate the presence of multiple microplastics in human semen and urine and their association with sperm quality in a multi-site study across China.

METHODS

We conducted a cross-sectional study involving 113 male participants from three regions in China. Semen and urine samples were collected and analysed using Raman microscopy to detect eight types of microplastics: polystyrene (PS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). Semen quality parameters, including total sperm count, concentration, motility, and morphology, were assessed. Statistical analyses, including single and multi-variable models, were used to evaluate the relationship between microplastic exposure and semen quality, with a focus on PTFE, after adjusting confounding factors of age, body mass index (BMI), smoking, alcohol drinking, and sites.

FINDINGS

Microplastics were detected in all semen and urine samples, with participants typically exposed to 3-5 different types. The detection rates of PS, PP and PE were the highest. Notably, PTFE exposure was significantly associated with decreased semen quality. Participants exposed to PTFE showed reductions in total sperm count [188.90 ± 163.71 vs. 207.67 ± 132.36 million, p = 0.091], sperm concentration [52.13 ± 47.47 vs. 58.32 ± 37.26 million/mL, p = 0.041], and progressive motility [40.29% ± 19.06 vs. 34.11% ± 17.02, p = 0.083]. The multi-linear regression analysis indicated that each additional type of microplastic exposure was associated with a significant decrease in total sperm number [β = -15.4 (95% CI: -25.6, -5.2)], sperm concentration [β = -7.2 (95% CI: -12.4, -2.0)], and progressive motility [β = -8.3 (95% CI: -13.5, -3.1)]. Latent category analysis further refined these groups by types of microplastic exposure, highlighting specific types more strongly associated with decreased semen quality (OR = 3.5, 95% CI: 1.8, 6.9, p < 0.001). The nomogram can be used to assess the risk of sperm damage by combining the type of microplastic exposure in urine with age and BMI.

INTERPRETATION

Our findings highlight the potential reproductive health risks posed by microplastic contamination, particularly PTFE, a non-stick pan coating material, and raise concerns about the potential of urine testing as an indicator of male reproductive microplastic exposure. Future research is warranted to further elucidate the mechanisms underlying the adverse effects of microplastics on male fertility and cross-generational effects.

FUNDING

This study was funded by the Clinical Research Project of Shanghai Municipal Commission of Health and Family planning (20224Y0085), Open Fund Project of Guangdong Academy of Medical Sciences (YKY-KF202202), CAMS Innovation Fund for Medical Sciences (2019-I2M-5-064), Shanghai Clinical Research Center for Gynecological Diseases (22MC1940200), Shanghai Urogenital System Diseases Research Centre (2022ZZ01012), Key Discipline Construction Project (2023-2025) of Three-Year Initiative Plan for Strengthening Public Health System Construction in Shanghai (GWVI-11.1-35, GWVI-11.2-YQ29) and Shanghai Frontiers Science Research Base of Reproduction and Development.

Preparation of multi-barrier and multi-functional paper-based materials by chitosan, ethyl cellulose and green walnut husk biorefinery products for sustainable food packaging

The growing interest in paper-based materials for packaging is driven by their renewable and eco-friendly characteristics. However, their poor barrier performance against water, oil, and gas limits their application in the food packaging industry. In this study, we developed a simple dual-layer coating method to create water- and oil-repellent, gas barrier, antioxidant, and antibacterial paper-based materials using naturally-derived materials, including chitosan (CS), ethyl cellulose (EC), and cascade biorefinery products from green walnut husk (GWHE and CNC). The bottom CS/CNC oil-resistant coating and the top EC/GWHE water-resistant coating were applied to the paper surface. The synergistic effect of these coatings enhances the gas barrier and imparts functional properties to the paper. Compared to uncoated paper, the dual-layer-coated paper demonstrated a 239.1 % increase in tensile index, a higher kit rating value of 12/12, a lower Cobb 60 value of 3.21 mg/m2, a 44.0 % decrease in water vapor permeability (WVP), and a 90.7 % reduction in air permeability (AP). Additionally, this coated paper exhibited good antioxidant and antibacterial properties and favorable biodegradability. This study provides novel insights into the valorization of GWH waste and presents a sustainable strategy for producing high-performance paper-based materials for food packaging applications.

Combined effects of microplastics and pharmaceutical and personal care products on algae: A critical review

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are ubiquitous in aquatic environments. Algae play an important role in aquatic environments. Thus, it is important to study the response of algae to combined exposure of MPs and PPCPs. Here, we review the effects of MPs and PPCPs on algae. First, the individual effects of MPs and PPCPs on algae were summarized. Second, the combined effects of MPs and PPCPs on algae were systematically analyzed. (1) Antagonism: ① when the MPs are too large to enter the algal cells, the adsorption of PPCPs onto MPs results in decreased the contact of MPs and PPCPs with algae; ② PPCPs and MPs have opposing actions on the same biological target; ③ MPs increase the activity of metabolic enzymes in algae, thus promoting the PPCP degradation. (2) Synergy: ① when the MPs are small enough to enter algal cells, the adsorption of PPCPs on MPs promotes the entry of PPCPs; ② when MPs are negatively charged, the adsorption of positively charged PPCPs by MPs decreases the electrostatic repulsion, increasing the interaction between algae and MPs; ③ complementary modes of action between MPs and PPCPs show combined effects on the same biological target. Third, the relative importance of the factors that impact the combined effects are evaluated using the random forest model decreased in the following order: PPCP types > algal species > MP size > MP concentration > MP types > exposure time. Finally, future directions for the combined effects of MPs and PPCPs are proposed, which will facilitate a better understanding of the environmental fate and risks of both MPs and PPCPs.

Global microplastic fiber pollution from domestic laundry

The rapid expansion of fast fashion has significantly increased microplastic fiber (MPF) release during laundry practices, accounting for approximately one-third of primary microplastics entering the ocean. Currently, a significant gap exists in global-scale research on the release of MPFs from washing textiles. This study introduces an innovative empirical model to assess the spatial distribution of MPF emissions. The model estimates an annual global emission of 5.69 million tons of MPFs from laundry. Of this total, machine washing accounts for the majority (93.7 %), with hand washing contributing the remaining 6.3 %. As the primary source of MPF pollution, Asia's emissions reach 3.71 million tons, far exceeding those of North America (1.18 million tons) and Europe (0.45 million tons). The primary issue is that wastewater management efficiency varies significantly worldwide. In Asia, there is persistently high discharge of MPFs into natural waters, and the removal efficiency of wastewater treatment plants is still comparatively low. In contrast, the United States and many European countries exhibit better MPF retention. The global nature of this challenge mandates international collaboration for comprehensive environmental conservation. Our study provides the first high-resolution global distribution map of MPF emissions and discharge into natural waters, establishing a data foundation for global and regional management of microplastics originating from household laundry sources.

Kelp forest food webs as hot spots for the accumulation of microplastic and polybrominated diphenyl ether pollutants

Kelp forests (KFs) are one of the most significant marine ecosystems in the planet. They serve as a refuge for a wide variety of marine species of ecological and economic importance. Additionally, they aid with carbon sequestration, safeguard the coastline, and maintain water quality. Microplastic (MP) and polybrominated diphenyl ethers (PBDEs) concentrations were analyzed across trophic levels in KFs around Todos Santos Bay. Spatial variation patterns were compared at three sites in 2021 and temporal change at Todos Santos Island (TSI) in 2021 and 2022. We analyzed these MPs and PBDEs in water, primary producers (Macrocystis pyrifera), grazers (Strongylocentrotus purpuratus), predators (Semicossyphus pulcher), and kelp detritus. MPs were identified in all samples (11 synthetic and 1 semisynthetic polymer) and confirmed using Fourier-transform infrared microspectroscopy-attenuated total reflectance (μ-FTIR-ATR). The most abundant type of MP is polyester fibers. Statistically significant variations in MP concentration were found only in kelps, with the greatest average concentrations in medium-depth kelps from TSI in 2022 (0.73 ± 0.58 MP g-1 ww) and in the kelp detritus from TSI in 2021 (0.96 ± 0.64 MP g-1 ww). Similarly, PBDEs were found in all samples, with the largest concentration found in sea urchins from Punta San Miguel (0.93 ± 0.24 ng g-1 ww). The similarity of the polymers can indicate a trophic transfer of MPs. This study shows the extensive presence of MP and PBDE subtropical trophic web of a KF, but correlating these compounds in environmental samples is highly complex, influenced by numerous factors that could affect their presence and behavior. However, this suggests that there is a potential risk to the systems and the services that KFs offer.

Origin, types, and contribution of emerging pollutants to environmental degradation and their remediation by physical and chemical techniques

The growing presence of emerging pollutants (EPs) in aquatic environments, as well as their harmful impacts on the biosphere and humans, has become a global concern. Recent developments and advancements in pharmaceuticals, agricultural practices, industrial activities, and human personal care substances have paved the way for drastic changes in EP concentrations and impacts on the ecosystem. As a result, it is critical to mitigate EP's harmful effects before they jeopardize the ecological equilibrium of the overall ecosystem and the sustainable existence of life on Earth. This review comprehensively documented the types, origins, and remediation strategies of EPs, and underscored the significance of this study in the current context. We briefly stated the major classification of EPs based on their organic and inorganic nature. Furthermore, this review systematically evaluates the occurrence of EPs due to the fast-changing ecological scenarios and their impact on human health. Recent studies have critically discussed the emerging physical and chemical processes for EP removal, highlighting the limitations of conventional remediation technologies. We reviewed and presented the challenges associated with EP remediation and degradation using several methods, including physical and chemical methods, with the application of recent technologies. The EP types and various methods discussed in this review help the researchers understand the nature of present-day EPs and utilize an efficient method of choice for EP removal and management in the future for sustainable life and development activities on the planet.

Distribution and risk assessment of microplastics in water, sediment and brine shrimps in a remote salt lake on the Tibetan Plateau, China

Microplastics (MPs) are pervasive environmental contaminants that have infiltrated even the most remote ecosystems. Despite their widespread distribution, the transfer patterns and impacts of MPs in remote lakes remain poorly understood. This study aimed to address the knowledge gap regarding the pathways and consequences of MP pollution in these isolated environments. Focusing on Kyêbxang Co, a remote salt lake in Tibet, this study investigated the transfer patterns, sources and ecological impacts of MPs, providing insights into their mobility and fate in pristine ecosystems. Water, sediment and biota (brine shrimp) samples from Kyêbxang Co, collected during the summer of 2020, were analyzed using µ-Raman spectroscopy to determine MP abundances, polymer types and potential sources. Findings indicated significant MP contamination in all examined media, with concentrations highlighting the role of runoff in transporting MPs to remote locations. The majority of detected MPs were small fragments (<0.5 mm), constituting over 93 %, with polypropylene being the predominant polymer type. The presence of a halocline may slow the descent of MPs, potentially increasing the exposure and ingestion risk to brine shrimp. Despite the currently low ecological risk estimated for MPs, this study underscores the need for long-term monitoring and development of a comprehensive ecological risk assessment model for MPs.

Critical review on unveiling the toxic and recalcitrant effects of microplastics in aquatic ecosystems and their degradation by microbes

Production of synthetic plastic obtained from fossil fuels are considered as a constantly growing problem and lack in the management of plastic waste has led to severe microplastic pollution in the aquatic ecosystem. Plastic particles less than 5mm are termed as microplastics (MPs), these are pervasive in water and soil, it can also withstand longer period of time with high durability. It can be broken down into smaller particles and can be adsorbed by various life-forms. Most marine organisms tend to consume plastic debris that can be accumulated easily into the vertebrates, invertebrates and planktonic entities. Often these plastic particles surpass the food chain, resulting in the damage of various organs and inhibiting the uptake of food due to the accumulation of microplastics. In this review, the physical and chemical properties of microplastics, as well as their effects on the environment and toxicity of their chemical constituents are discussed. In addition, the paper also sheds light on the potential of microorganisms such as bacteria, fungi, and algae which play a pivotal role in the process of microplastics degradation. The mechanism of microbial degradation, the factors that affect degradation, and the current advancements in genetic and metabolic engineering of microbes to promote degradation are also summarized. The paper also provides information on the bacterial, algal and fungal degradation mechanism including the possible enzymes involved in microplastic degradation. It also investigates the difficulties, limitations, and potential developments that may occur in the field of microbial microplastic degradation.

A critical review of microplastics in aquatic ecosystems: Degradation mechanisms and removing strategies

Plastic waste discarded into aquatic environments gradually degrades into smaller fragments, known as microplastics (MPs), which range in size from 0.05 to 5 mm. The ubiquity of MPs poses a significant threat to aquatic ecosystems and, by extension, human health, as these particles are ingested by various marine organisms including zooplankton, crustaceans, and fish, eventually entering the human food chain. This contamination threatens the entire ecological balance, encompassing food safety and the health of aquatic systems. Consequently, developing effective MP removal technologies has emerged as a critical area of research. Here, we summarize the mechanisms and recently reported strategies for removing MPs from aquatic ecosystems. Strategies combining physical and chemical pretreatments with microbial degradation have shown promise in decomposing MPs. Microorganisms such as bacteria, fungi, algae, and specific enzymes are being leveraged in MP remediation efforts. Recent advancements have focused on innovative methods such as membrane bioreactors, synthetic biology, organosilane-based techniques, biofilm-mediated remediation, and nanomaterial-enabled strategies, with nano-enabled technologies demonstrating substantial potential to enhance MP removal efficiency. This review aims to stimulate further innovation in effective MP removal methods, promoting environmental and social well-being.

A review of the neurobehavioural, physiological, and reproductive toxicity of microplastics in fishes

Microplastics (MPs) have emerged as widespread environmental pollutants, causing significant threats to aquatic ecosystems and organisms. This review examines the toxic effects of MPs on fishes, with a focus on neurobehavioural, physiological, and reproductive impacts, as well as the underlying mechanisms of toxicity. Evidence indicates that MPs induce a range of neurobehavioural abnormalities in fishes, affecting social interactions and cognitive functions. Altered neurotransmitter levels are identified as a key mechanism driving behavioural alterations following MP exposure. Physiological abnormalities in fishes exposed to MPs are also reported, including neurotoxicity, immunotoxicity, and oxidative stress. These physiological disruptions can compromise the individual health of aquatic organisms. Furthermore, reproductive abnormalities linked to MP exposure are discussed, with a particular emphasis on disruptions in endocrine signaling pathways. These disruptions can impair reproductive success in fish species, impacting population numbers. Here we explore the critical role of endocrine disruptions in mediating reproductive effects after exposure to MPs, focusing primarily on the hypothalamic-pituitary-gonadal axis. Our review highlights the urgent need for interdisciplinary research efforts aimed at elucidating the full extent of MP toxicity and its implications for aquatic ecosystems. Lastly, we identify knowledge gaps for future research, including investigations into the transgenerational impacts, if any, of MP exposure and quantifying synergetic/antagonistic effects of MPs with other environmental pollutants. This expanded knowledge regarding the potential risks of MPs to aquatic wildlife is expected to aid policymakers in developing mitigation strategies to protect aquatic 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.

Overview of the environmental risks of microplastics and their controlled degradation from the perspective of free radicals

Owing to the significant environmental threat posed by microplastics (MPs) of varying properties, MPs research has garnered considerable attention in current academic discourse. Addressing MPs in river-lake water systems, existing studies have seldom systematically revealed the role of free radicals in the aging/degradation process of MPs. Hence, this review aims to first analyze the pollution distribution and environmental risks of MPs in river-lake water systems and to elaborate the crucial role of free radicals in them. After that, the study delves into the advancements in free radical-mediated degradation techniques for MPs, emphasizing the significance of both the generation and elimination of free radicals. Furthermore, a novel approach is proposed to precisely govern the controlled generation of free radicals for MPs' degradation by interfacial modification of the material structure. Hopefully, it will shed valuable insights for the effective control and reduction of MPs in river-lake water systems.

Superior sequence-controlled poly(L-lactide)-based bioplastic with tunable seawater biodegradation

Developing superior-performance marine-biodegradable plastics remains a critical challenge in mitigating marine plastic pollution. Commercially available biodegradable polymers, such as poly(L-lactide) (PLA), undergo slow degradation in complex marine environments. This study introduces an innovative bioplastic design that employs a facile ring-opening and coupling reaction to incorporate hydrophilic polyethylene glycol (PEG) into PLA, yielding PEG-PLA copolymers with either sequence-controlled alternating or random structures. These materials exhibit exceptional toughness in both wet and dry states, with an elongation at break of 1446.8% in the wet state. Specifically, PEG4kPLA2k copolymer biodegraded rapidly in proteinase K enzymatic solutions and had a significant weight loss of 71.5% after 28 d in seawater. The degradation primarily affects the PLA segments within the PEG-PLA copolymer, as evidenced by structural changes confirmed through comprehensive characterization techniques. The seawater biodegradability, in line with the Organization for Economic Cooperation and Development 306 Marine biodegradation test guideline, reached 72.63%, verified by quantitative biochemical oxygen demand analysis, demonstrating rapid chain scission in marine environments. The capacity of PEG-PLA bioplastic to withstand DI water and rapidly biodegrade in seawater makes it a promising candidate for preventing marine plastic pollution.

Combined exposure of PS-MPs with NaF induces Sertoli cell death and dysfunction via ferroptosis and apoptosis

The individual toxicity of sodium fluoride (NaF) and microplastics (MPs) has been extensively documented. Owing to their high specific surface area, widespread presence and durability, MPs can adsorb a broad spectrum of environmental contaminants into the organism. However, the combined toxicity of NaF and MPs has not been investigated. This study aimed to assess the effects of combined exposure to NaF and MPs on the function of testicular Sertoli cells (SCs) in male mice, and to investigate the underlying molecular mechanisms. The study revealed that combined exposure to NaF and MPs resulted in a decrease in the negative surface charge of MPs, along with an increase in the number of MPs entering the SCs. Through in vivo observation of the testicular pathological structure, spermatogenesis, and cell apoptosis in 180-day-old male mice, we discovered that combined exposure to NaF (80 mg/L) and MPs (10 mg/L) heightened reproductive toxicity compared to the individual exposure groups. This was evidenced by testicular structural defects, impaired spermatogenesis, and increased testicular cell apoptosis. Our in vitro studies showed that NaF (21 μg/mL) and MPs (100 μg/mL) synergistically induced SCs apoptosis and ferroptosis, leading to a reduction in SCs number and dysfunction. This ultimately resulted in structural and functional damage to the testes. Our findings demonstrate, for the first time, the synergistic effects of NaF and MPs on reproductive toxicity in mammals. These insights may provide valuable contributions to co-toxicity studies involving MPs and other environmental pollutants.

Multigenerational resilience of the marine rotifer Brachionus plicatilis to high temperature after additive exposure to high salinity and nanoplastics

To study multigenerational resilience to high temperature (HT) conditions, we exposed Brachionus plicatilis marine rotifers to HT, high salinity (HS), and nanoplastics (NPs), and measured reproductive and life-cycle endpoints. After exposure to HT, rotifer lifespans were reduced, but daily production of offspring increased. However, both combined HT/HS and HT/HS/NP exposure led to additional decreases in longevity and reproductive ability; the antioxidant defense mechanisms of the rotifers were also notably upregulated as measured by reactive oxygen species levels. Fatty-acid profiles were reduced in all conditions. In multigenerational experiments, the negative effects of HT dissipated rapidly; however, the effects of HT/HS and HT/HS/NPs required four generations to disappear completely. The findings indicated that B. plicatilis were able to recover from these environmental stressors. This study demonstrated the resilience of aquatic organisms in response to changing environmental conditions and provides insights into the complex interactions of different abiotic stressors.

Occurrence and abundance of microplastics in surface water of Songkhla Lagoon

Background

Microplastic (MP) pollution is now a global critical issue and has been the subject of considerable worry for multiple various types of habitats, notably in lagoons which are coastal areas connected to the ocean. MPs are of concern, particularly because floating MP in surface water can be ingested by a number of marine organisms. There are several lagoons along Southeast Asia's coastline, but Songkhla Lagoon is Thailand's only exit with a rich biodiversity. To date, there has been little research undertaken on MP in this lagoon, so there is a pressing need to learn more about the presence of MP in the lagoon's water.

Methods

We investigate MPs in the surface water of Songkhla Lagoon, Thailand. Sampling took place at ten stations in the lagoon during the wet season in December 2022 and the dry season in February 2023. Samples were digested with hydrogen peroxide to remove organic matter followed by density separation using saturated sodium chloride. MPs were visually examined under a stereo microscope to describe and determine the shape, size, and color. Polymer type was identified using a micro Fourier transform infrared (FTIR) spectrometer. Moreover, the in-situ of water quality of the surface water was measured using a multi-parameter probe. A Mann-Whitney U test was performed to investigate the variations in MP levels and water quality parameters between the wet and dry seasons. Correlation analysis (Spearman rho) was used to determine the significance of correlations between MP and water quality (p < 0.05).

Results

MPs were detected at all ten of the sites sampled. The most abundant MPs were small size class (<500 µm, primarily consisting of fibers). Five types of polymers were seen in surface water, including polyethylene terephthalate, rayon, polypropylene, polyester, and poly (ethylene:propylene). Rayon and polyester were the dominant polymers. Additionally, the most dominant color of MPs in the wet and dry season was black and blue, respectively. The mean contents of MPs in the wet and dry season were 0.43 ± 0.18 and 0.34 ± 0.08 items/L, respectively. The Mann-Whitney U test suggested a significant difference between water quality in the wet and dry seasons (p < 0.05). Correlation analysis (Spearman rho) indicated a negative significant difference relationship between the MPs and the values of total dissolved solid (TDS) in the wet season (r = -0.821, p = <0.05), revealing that the large amounts of MPs may possibly be dispersed within surface water bodies with low TDS concentrations. Based on the overall findings, MP pollution in the surface water of the lagoon is not found to be influenced by the seasonal context. Rivers flowing into the lagoon, especially the U-Taphao River, may be a principal pathway contributing to increased MP pollution loading in the lagoon. The results can be used as baseline data to undertake further research work relevant to sources, fates, distribution, and impacts of MPs in other coastal lagoons.

Microplastics alter the microbiota-mediated phosphorus profiles at sediment-water interface: Distinct microbial effects between sediment and plastisphere

Microplastics (MPs) are ubiquitous in freshwater sediments, raising concern about their potential impacts on ecosystem services. However, the specific impacts of microbiota mediated by MPs in sediment and plastisphere compartments on P availability remain elusive. This investigation conducted a series of microcosm experiments utilizing eutrophic lake sediment amended with fuel-based polyethylene terephthalate (PET), bio-based polylactic acid (PLA) MPs, and a natural cobblestone substrate to unravel their effects. The findings highlighted that MPs induced alterations in bacterial communities in both sediment and plastisphere, consequently modifying P availabilities at the sediment-water interface (SWI). In comparison to non-biodegradable PET, biodegradable PLA MPs presented higher proportions of specific bacteria and functional genes associated with P profiles, such as Firmicutes, Ignavibacteriota, and P mineralizing genes in the sediment and plastisphere. This, in turn, elevated the levels of soluble reactive P in the porewater by 54.19 % (0-1 cm), 55.81 % (1-3 cm), and 18.24 % (3-5 cm), respectively. Additionally, PLA obviously altered P immobilization capacity and bioavailability, increasing the organic P fraction. Whereas, inert cobblestone exhibited negligible influence on P biogeochemical processes during the incubation. Moreover, the biofilm communities and those in the surrounding sediment specifically contributed to the changes in P profiles at the SWI. The functional genes associated with P profiles in the sediment mainly concentrate on P mineralization and P uptake/transport. In the plastisphere, P activation genes are obviously affected under MP exposure. This study fills the knowledge gap concerning the repercussions of MPs on ecosystem services.

Assessment and accumulation of microplastics in the Indian riverine systems: Risk assessment and implications of translocation across the water-to-fish continuum

Microplastic (MP) pollution has engulfed global aquatic systems, and the concerns about microplastic translocation and bioaccumulation in fish and other aquatic organisms are now an unpleasant truth. In the past few years, MP pollution in freshwater systems, particularly rivers and subsequently in freshwater organisms, especially in fish, has caught the attention of researchers. Rivers provide livelihood to approximately 40 % of the global population through food and potable water. Hence, assessment of emerging contaminants like microplastics in rivers and the associated fauna is crucial. This study assessed microplastics (MPs) in fish, sediment and freshwater samples across the third largest riverine system of peninsular India, the Mahanadi River. The number concentrations of MPs measured in water, sediment and fish ranged from 337.5 ± 54.4-1333.3 ± 557.2 MPs/m3, 14.7 ± 3.7-69.3 ± 10.1 MPs/kg. Dry weight and 0.4-3.2 MPs/Fish, respectively. Surprisingly, MPs were found in every second fish sample, with a higher MP number in the gut than in the gills. Black and blue coloured filaments with <0.5 mm size were the dominant MPs with polypropylene and polyethylene polymers in abundance. The Polymer Hazard Index (PHI) and the Potential Ecological Risk Index (PERI) studies revealed that the majority of the sampling sites fell in Risk category V (dangerous category). An irregular trend in the MP concentration was observed downstream of the river, though relatively elevated MP concentrations in water and fish samples were observed downstream of the river. t-Distributed Stochastic Neighbour Embedding (t-SNE) unveiled distinct patterns in MP distribution with a higher similarity exhibited in the MPs found in fish gill and gut samples, unlike water and sediment, which shared certain characteristics. The findings in the current study contribute to filling the knowledge gap of MP assessment and accumulation in global freshwater systems and highlight the microplastic contamination and accumulation in fish with its potential implications on human health.

Natural iron-containing minerals catalyze the degradation of polypropylene microplastics: a route to self-remediation learnt from the environment

Virgin and environmentally aged polypropylene (PP) micropowders (V-PP and E-PP, respectively) were used as reference microplastics (MPs) in comparative photo- and thermo-oxidative ageing experiments performed on their mixtures with a natural ferrous sand (NS) and with a metal-free silica sand (QS). The ferrous NS was found to catalyze the photo-oxidative degradation of V-PP after both UV and simulated solar light irradiation. The catalytic activity in the V-PP/NS mixture was highlighted by the comparatively higher fraction of photo-oxidized PP extracted in dichloromethane, and the higher carbonyl index of the bulk polymer extracted with boiling xylene, when compared with the V-PP/QS mixture. Similarly, NS showed a catalytic effect on the thermal degradation (at T = 60 °C) of E-PP. The results obtained indicate that, under suitable environmental conditions (in this case, an iron-containing sediment or soil matrix, combined with simulated solar irradiation), the degradation of some types of MPs could be much faster than anticipated. Given the widespread presence of iron minerals (including the magnetite and iron-rich serpentine found in NS) in both coastal and mainland soils and sediments, a higher than expected resilience of the environment to the contamination by this class of pollutants is anticipated, and possible routes to remediation of polluted natural environments by eco-compatible iron-based minerals are envisaged.

Plant Cadmium Toxicity and Biomarkers Are Differentially Modulated by Degradable and Nondegradable Microplastics in Soil

The impact of microplastics (MPs) as emerging pollutants on plant heavy metal toxicity has been extensively reported in vegetable-soil systems over recent years. However, little attention has been given to cultivar variations between degradable and non-degradable MPs. This study investigated the effects of degradable polylactic acid (PLA) and nondegradable polypropylene (PP) MPs on plant growth and biomarker (malonaldehyde (MDA) and antioxidant enzymes) performance in Cd-contaminated arable soil. The results show that both types of MPs significantly impacted plant biomass and biomarker contents across all three Cd levels. The degree of impact was significantly sensitive to both the type and dose of MPs, as they reduced the soil pH and cation exchange capacity (CEC) while increasing soil dissolved organic carbon (DOC), microbial biomass carbon, and nitrogen. PP exhibited greater root growth inhibition and phytotoxicity at higher doses of 1% and 5% compared to PLA. Specifically, the highest MDA contents were 1.44 and 2.20 mmol mg-1 protein for shoots and roots, respectively, in the 5% PLA treatment under a 10.1 mg kg-1 Cd level, which were 1.22 and 1.18 times higher than those in corresponding treatments of 5% PP. Overall, PLA had less significant effects on plant phytotoxicity, Cd availability, and soil properties compared to PP. Regression pathway analysis indicated that MPs increased shoot Cd uptake by altering both soil physical-chemical and microbial characteristics. Among the soil variables, pH, CEC, and Cd bioavailability were found to play vital roles. Yet, no single variable acts alone in the mechanism for plant Cd uptake. PLAs are suggested to replace conventional non-biodegradable plastics to control environmental MP pollution, particularly in agricultural systems with higher Cd contamination. However, the long-term effects of the by-products generated during the biodegradation process require further investigation.

Microplastics have additive effects on cadmium accumulation and toxicity in Rice flower carp (Procypris merus)

Procypris merus, a local fish species found in Guangxi, China is often exposed to both microplastics (MPs) and Cd. However, it remains unclear how these two pollutants affect P. merus. Therefore, we investigated the effects of MPs on Cd accumulation in P. merus. To this end, P. merus was separately exposed to Cd and MPs (500 μg/L) or their combination for 14 days. We found that MPs enhanced Cd accumulation in liver and gills of P. merus. Further, both the single-contaminant (MP and Cd) and combined treatments resulted in lesions in these two tissues, with more severe damage associated with the combined treatment. Even though the effect of MP on the antioxidant defense system of P. merus was limited, the Cd-only and combined treatments considerably affected the antioxidant parameters of P. merus, with the combined treatment showing a stronger effect. GO and KEGG analyses revealed that the differentially expressed genes (DEGs; TNF-related apoptosis-inducing ligand receptor, trail-r) in the Cd-only treatment group were enriched for immune-related GO terms and cell growth and death related pathways, indicating that Cd toxicity affected immune defense in P. merus. The MP-only treatment downregulated DEGs (acyl-CoA synthetase long chain family member 1a, acsl1a) related to lipid metabolism, possibly leading to lipid accumulation in the liver. The combined treatment also upregulated DEGs (aspartate aminotransferase 1, ast 1) associated with immune-related GO terms and amino acid metabolism pathways, suggesting that it affected immune function in P. merus, thereby negatively impacting its health. Results indicated that MPs have additive effects on Cd accumulation and toxicity in rice flower carp. Consequently, MPs ingested by P. merus can promote Cd accumulation, more adverse effects on the health may occur after combined exposure, which can eventually reach humans through the food chain and pose potential risks to human health.