Small plastic fragments: A bridge between large plastic debris and micro- & nano-plastics

Unveiling the deep-sea microplastic Odyssey: Characteristics, distribution, and ecological implications in Pacific Ocean sediments

Microplastics (MPs) in deep-sea environments are a growing concern due to their potential ecological risks and the deep sea's role in global biogeochemical cycles. This study investigated the characteristics and distribution of MPs in sediments from the Pacific Ocean at depths of 4900-7016 m across three regions: Western Pacific (WP), Central Pacific (CP), and Eastern Pacific (EP). MPs were detected at all sampling sites, with the highest abundance in WP (111.3 ± 75.1 items/kg dw) and the lowest in CP (49.4 ± 18.7 items/kg dw). Site S9 was recorded as the peak abundance (270.1 ± 107.4 items/kg dw) in WP. MPs were predominantly fibers (94.8 %) in black, gray, and blue hues, mainly composed of polyester and rayon. Statistical analysis showed significant regional variations, reflecting anthropogenic impacts and complex deposition mechanisms. Risk assessments indicated low to medium hazard levels (PLI <10, PRI ≤ III), but the potential ecological impacts remain concerning. This study highlights the significant variability in MP distribution across regions, emphasizing the importance of region-specific mitigation strategies. It calls for comprehensive, long-term research to better understand MP sources, deposition processes, and ecological impacts in deep-sea ecosystems.

Occurrence of microplastics in bottled water from Croatia: a Raman spectroscopy approach

The occurrence of microplastics (MPs) in bottled water is still largely unexplored in Croatia. This study fills this gap by analysing six water brands available on the Croatian market, all bottled in either virgin or recycled polyethylene terephthalate (PET). In order to analyse microplastics down to a size of 1 µm, the water from the purchased bottles was filtered with silicon filters with a pore size of 1 µm and then micro-Raman spectroscopy was performed. A significant reduction in analysis time was achieved by using a randomly selected filter area of 12.05 mm2 instead of the conventional 100 mm2. The results showed that polyethylene (PE), PET, and polyamide (PA) were found in all six brands and the blank. The highest detection frequency was found for PE (N = 19), followed by PET (N = 17) and PA (N = 14). Polyvinyl chloride (PVC) was found only in one brand, but in all three subsamples, packaged in recycled PET. By far the highest detection frequency of MPs occurred in the smallest fraction at a length < 5 µm. The highest number of MPs was for PET with 45% of the total amount, followed by PE (37%). Although MPs were identified in the blank water sample, the number was 12% of the total. Interestingly, the bottled water in virgin PET containers had more MPs than that in recycled PET. It should be noted that the purification system used to produce ultrapure water produced MPs, which poses an additional analytical challenge. The results should be considered as a snapshot and further monitoring is necessary to assess the extent of MP contamination of drinking water and to characterise the types of polymers and sources of the MPs. The current findings raise concerns about the presence of MPs in bottled water and warrant a thorough risk assessment to evaluate potential long-term health effects on humans.

Mapping marine debris hotspots on Boa Vista Island, Cabo Verde

Coastal ecosystems are under increasing threat, with the accumulation of marine debris-particularly plastics-posing significant ecological risks. Oceanic islands are especially vulnerable due to ocean currents depositing marine debris on their exposed shores. This study presents the first assessment of marine debris accumulation on sandy beaches of Boa Vista Island, Cabo Verde. Using a combination of drone-based aerial imagery and sand sampling, we quantified micro-, meso-, and macro-debris densities across 29 beaches. North- and east-facing beaches of the island showed the highest accumulation of marine debris (>85 % plastics), driven by ocean currents. Mean drone-based densities varied between 5 and 2371 macro-debris items per 100 m of beach length, totalling 23,085 items. As for sand samples, mean densities ranged from 0 to 1639 items/m2, totalling 4272 large microplastics, 1221 mesoplastics and 350 macroplastics. The easternmost beach, Ponta de Roque, alone accounted for 31 % of the total debris recorded across all locations, with sand samples averaging 1639 items/m2 (1453 microplastics larger than 1 mm), and drone-based surveys averaging 68 macro-debris items/100 m2. Fishing-related items comprised ∼24 % of drone-surveyed debris, suggesting input from the Northwest African coast. Plastic fragments predominated, with significant correlations between drone-surveyed macro-plastics and sand-sampled large microplastic densities. Drone surveys effectively identified marine debris hotspots, aligning with ground-based data. This study provides important baseline data for long-term monitoring in the archipelago and offers a transferable methodology for assessing plastic pollution in other island systems.

Differentiating macroplastic and mesoplastic pollution on relatively clean beaches of central Philippines

Marine plastic litter exposed to different environmental conditions have the tendency to break and produce smaller plastic debris that threatens marine organism, tourism, livelihood, and health. However, our understanding on the distribution of different sizes of marine plastic litter in marine environments is still limited. This study assessed macroplastic and mesoplastic pollution in eleven residential and five non-residential beaches in Isabel and Merida, Leyte, Philippines. Macroplastics were collected within four quadrats in a delineated 100-m transect line parallel to the shoreline. Sampled litter was then counted, weighed, and sorted into categories. Subsequently, mesoplastic particles were collected from the same quadrats where macroplastic were collected. A total of 562 macroplastic litter and 38 mesoplastics were obtained. Residential sites recorded higher macroplastic and mesoplastic density compared to non-residential sites; however, this is not statistically significant. Dominant macroplastics were sando bags (26.69 %), while mesoplastics are fragmented (50 %), white and green (58 %), and mainly composed of polypropylene (PP) (34 %) as confirmed by FTIR-ATR. The brand audit revealed that Rebisco and PT Mayora Indah TBK were the largest food packaging plastic contributors on the site. Clean-Coast Index classified 75 % of the study sites as clean to moderately clean. Contamination Factors also classified sites having considerable to moderate contamination of mesoplastics. Macroplastic and mesoplastic are not correlated in the area. The result of this study signifies the need to create strategies and strengthen policies to combat plastic pollution. Furthermore, there is a need for industry intervention to produce less packaging and collective effort to achieve plastic net zero.

Cellulose-based multifunctional materials with robust hydrophobic, antibacterial, and antioxidant properties through dynamic cross-linked network structures

Environmental pollution and health problems caused by traditional non-degradable fossil-based plastics are significant concerns, rendering green and renewable bio-based materials, such as cellulose and C36-Priamine (1074), as attractive substitutes. In particular, the low plasticity of cellulose can be optimized using soft alkyl chains. Herein, multifunctional cellulose-based materials were constructed via covalent adaptable networks using the Schiff base reaction of oxidized microcrystalline cellulose with varying aldehyde (dialdehyde cellulose (DAC)) contents and C36-Priamine (1074). Subsequently, a series of DAC/1074 bio-based films were formed via a simple heat-pressing process (T = 90 °C). The resulting films exhibited excellent properties, including high stresses (16.8-28.6 MPa), high strains (4.94-25.38 %), good transparency (>80 %), excellent toughness (118.24-267.61 J/m3), and enhanced water resistance (92.9-94.5 %) and hydrophobicity (water contact angle of 120.6°-132.83°). Owing to their excellent antioxidant and antimicrobial properties, our prepared DAC/1074 films have diversified applications in food packaging, medical materials, and cosmetics.

Combined toxicity of microplastic fibers and dibutyl phthalate on algae: Synergistic or antagonistic?

Plastics, combined with plasticizers, have been widely utilized worldwide. Microplastic fibers (MPFs) and dibutyl phthalate (DBP) account for the most predominant microplastics and plasticizers detected in freshwater ecosystem, with their joint toxicity being limited studied. In this study, we employed freshwater algae (Chlorella vulgaris) as toxicity test model organism to assess their growth, photosynthesis, metabolism, and oxidative response when exposing to different concentrations of polypropylene MPFs and the co-exposure of DBP. In addition, the toxic interaction between MPFs and DBP was assessed by combining the integrated toxicity value (Integrated Biomarker Response version 2, IBRv2) and the mixture toxicity index (Effect Addition Index, EAI). Our results demonstrated significant toxic effects of MPFs and DBP on C. vulgaris, and highlighted their dynamic interactions with C. vulgaris. Specifically, when combining with DBP, MPFs with high concentrations exhibited significantly increase in algae growth inhibition, photosynthetic pigment contents (Chl-a, Chl-b, and carotenoids), protein contents, and oxidative enzymes (SOD, CAT, and MDA). In terms of integrated toxicity values, higher IBRv2 values were recorded by the combined exposure of MPFs and DBP in contrast with the sole exposure groups, indicating that the combined exposure caused more severe damage to photosynthesis, oxidation and metabolism. In addition, our study recorded synergistic combined toxicity when MPFs were in high concentrations, whereas antagonistic combined toxicity when MPFs were in low concentrations. Our study highlights the MPFs concentration-dependent combined toxicity (synergistic or antagonistic) when exposing to microplastics and plasticizers in freshwater ecosystems.

Spatial mapping and risk assessment of microplastic contamination in drinking water catchments from north of the Persian Gulf

Microplastics (MPs) are emerging contaminants in drinking water that raise global concerns due to their health risks and long-term environmental persistence. These tiny plastic particles can accumulate within human bodies and ecosystems, making it essential to understand their presence and behavior in water sources, especially in drinking water. In Khuzestan Province, which is of strategic importance in the Gulf region. This study assesses the concentration and types of MPs entering and leaving these 11 treatment plants. In untreated water, particle size analysis revealed that 50% of MPs were measured under 101 µm, with fibers being the most common type (47%), followed by fragments and pellets. Although treatment processes reduced overall MP concentrations, fibers remained the dominant residual type, making up 71% of the MPs in treated water. The main polymers identified were polyethylene (PE) and polypropylene (PP), with PE accounting for up to 75% of MPs in some areas. In terms of color, black/gray MPs were most prevalent (45%), followed by blue, red/pink, yellow/orange, and white/clear particles. While most treatment plants achieved significant reductions in MP levels, some were less effective, likely due to differences in treatment technologies. Notably, the S10 plant in Bandar Mahshahr had especially high inlet MP levels, possibly due to the region's high industrial and human activities. Estimated daily intake (EDI) for adults was approximately 0.00482 MPs per kg of body weight per day, with children having a higher intake of around 0.01866 MPs per kg per day. These findings highlight the need to enhance treatment technologies, control upstream MP sources, and establish routine monitoring to protect water quality in Khuzestan and the wider Gulf region.

Mesoplastics: A Review of Contamination Status, Analytical Methods, Pollution Sources, Potential Risks, and Future Perspectives of an Emerging Global Environmental Pollutant

Mesoplastics are emerging environmental pollutants that can pose a threat to the environment. Researching mesoplastics is crucial as they bridge the gap between macroplastics and microplastics by determining their role in plastic fragmentation and pathways, as well as their ecological impact. Investigating mesoplastic sources will help develop targeted policies and mitigation strategies to address plastic pollution. These pollutants are found across aquatic, terrestrial, and agricultural ecosystems. Unlike microplastics, mesoplastics are reviewed in the scientific literature. This paper focuses on existing published research on mesoplastics, determining the trends and synthesizing key findings related to mesoplastic pollution. Research primarily focused on marine and freshwater ecosystems, with surface water and beach sediments being the most studied compartments. Mesoplastics research often offers baseline data, with increased publications from 2014 to 2024, particularly in East Asia. However, certain ecosystems and regions remain underrepresented. Also, mesoplastics can disrupt ecosystems by degrading biodiversity, contaminating soils and waters, and affecting food chains. Mesoplastics can also become vectors for additives and pathogenic microorganisms, highlighting their environmental risks. Various factors influence mesoplastics' prevalence, including anthropogenic and non-anthropogenic activities. With this, future research should expand into less-studied ecosystems and regions, explore mesoplastic interactions with pollutants and organisms, and promote public awareness, education, and policy measures to reduce plastic use and mitigate pollution globally.

Two sides of the same coin: Weathering differences of plastic fragments in coastal environments around the globe

Plastic debris in coastal environments usually undergoes weathering due to various environmental conditions. However, the weathering effects on exposed and shaded sides of the same plastics are underexplored. In this study, 1573 plastic fragments were collected from 15 coastal sites worldwide between December 2021 and December 2022, and weathering experiments were conducted outdoors. The field investigation showed significant two-sided weathering differences of plastic fragments. The weathering morphology included biota, cracks, delamination, discoloration, etc. The weathering degree was assessed with three metrics, i.e., line density (0-58 mm/mm2), surface loss (0-92 %), and texture index (0-2). The 3D magnitudes of these three metrics revealed the two-sided weathering differences of plastic fragments. Specifically, 43 % of the samples had magnitudes > 5, indicating significant differences. Outdoor simulations suggested that sun-exposed sides developed more cracks, pores, and bubbles, while shaded sides remained smoother. After 12 months, the line density increased from 2.85 to 9.23 mm/mm² for polyethylene (PE) and 4.16-8.47 mm/mm² for polypropylene (PP) (p < 0.05). The carbonyl index increased from 0.50 to 1.70 (PE), from 0.18 to 1.10 (PP), and from 0.45 to 1.57 (polyvinyl chloride). This increase indicated oxidative degradation on sun-exposed sides. Our results highlighted the uneven degree of weathering on both sides of the same plastic fragment due to different environmental factors. The study provided critical insights for creating more accurate models to predict plastic degradation, which will help inform global strategies to reduce plastic pollution.

Enhanced competitiveness of Spirodela polyrhiza in co-culture with Salvinia natans under combined exposure to polystyrene nanoplastics and polychlorinated biphenyls

Micro- and nanoplastics (MNPs) and polychlorinated biphenyls (PCBs) are prevalent in the environment and pose potential threats to ecosystems. However, studies on the phytotoxicity of MNPs and PCBs on primary producers are limited. This study investigated the effects of polystyrene nanoplastics (PS-NPs, 10 mg/L) and 2,2',5,5'-tetrachlorobiphenyl (PCB-52, 0.1 mg/L), on the growth of Spirodela polyrhiza and Salvinia natans, and their impact on plant competitive ability under co-culture conditions. Laser confocal microscopy images revealed that PS-NPs accumulated on the leaf and root surfaces of both species. Combined exposure to PS-NPs and PCB-52 significantly inhibited the average specific and relative growth rates (RGR) of both species, reduced chlorophyll a and b levels, and slightly increased carotenoid content, disrupting the photosynthetic system. PCB-52 exacerbated PS-NPs accumulation on plants, leading to increased hydrogen peroxide (H2O2) and superoxide anion (O2-) production in both roots and leaves. This affects the activity of superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), and the soluble protein content. The combined treatment with PS-NPs and PCB-52 induced greater ecological stress in both species than the treatment with PS-NPs alone. In addition, the combined treatment with PS-NPs and PCB-52 significantly improved the relative yield and competition balance index of S. polyrhiza, indicating that PS-NPs + PCB-52 enhanced the competitive ability of S. polyrhiza when co-cultured with S. natans. This study confirmed the effects of co-exposure to PS-NPs and PCB-52 on aquatic plant growth and species competition, contributing to better insight into the ecological impacts of MNPs and organic pollutants.

Characterization, surface deformation analysis and sources of small plastic fragments collected in diverse environments of Egypt

This study investigates the sources and morphological characteristics of plastic waste across diverse Egyptian environments-marine (Mediterranean and Red Seas), freshwater (River Nile), and terrestrial (urban streets). Predominant plastics found in various marine areas include polyethylene and polypropylene, originating from both maritime and urban sources. In the Mediterranean, these plastics show higher levels of UV-induced degradation, resulting in fragments measuring 18-22 mm in size and 1-1.2 mm in thickness. The River Nile exhibits polystyrene fragments, with average sizes of 20-26 mm and thicknesses of 0.7-0.9 mm influenced by urban and agricultural runoff. Urban streets display a mix (polypropylene, polyethylene, and polystyrene), with thicker fragments (averaging 1.8 mm) due to mechanical wear and pollution. Analysis shows varying surface loss: Mediterranean (29 %), Red Sea (20-23 %), freshwater (18 %), and urban streets (up to 30 %), indicate differential degradation influenced by environmental conditions and human activities. These findings underscore the need for targeted policies to mitigate plastic pollution across Egypt's landscapes, crucial for global conservation efforts.

Segmentation of beach plastic fragments' contours based on self-organizing map and multi-shape descriptors: A rapid indication of fragmentation and wearing types

Environmental plastic fragments have been verified as byproducts of large plastic and its secondary pollutants including micro and nanoplastics. There are few quantitative studies available, but their contours have values for the weathering mechanisms. We used geometric descriptors, fractal dimensions, and Fourier descriptors to characterize field and artificial polyethylene and polypropylene samples as a means of investigating the contour characteristics. It provides a methodological framework for contour classification. Unsupervised classification was performed using self-organizing neural networks with size-invariance parameters. We revealed the isometric phenomenon of plastic fragments during fragmentation, i.e., that the degree of contour rounding and complexity increase and decrease, respectively, with decreasing fragment size. With an average error rate of 8.9 %, we can distinguish artificial samples from field samples. It was also validated by the difference in Carbonyl Index between groups. We propose a two-stage process for plastic fragmentation and give three types of contour features which were key in the description of fragmented contours, i.e., size, complexity, and rounding. Our work will improve the accuracy of characterizations regarding the weathering and fragmentation processes of certain kinds of plastic fragments. The contour parameters also have the potential to be applied in more realistic scenarios and varied polymers.

Size, shape, and elemental composition as predictors of microplastic surface erosion

The degradation of surfaces and its possible dependence on shape, size, and elemental composition of plastic particles were subjected. The surfaces of 146 microplastics were classified from smooth to fully eroded (%) by SEM/EDS. Structural elements and various additives were found on microplastics depending on their shapes. The surface of plastic items > 100 µm in length showed a relatively more eroded area than smaller ones, regardless of their shapes. Depending on shape, the percentage of surface erosion of irregularly shaped fragments < 100 µm was significantly enhanced compared to microbeads of the same size. These results may provide insights into assessing potential risks posed by microplastics and improve our understanding of the role of these parameters concerning possible adverse health effects on the environment.

Floating microplastic pollution in the vicinity of a marine protected area and semi-enclosed bay of Peru

A baseline survey for floating microplastics (MPs) in the vicinity of a marine protected area and semi-enclosed bay of northern Peru was carried out. An average concentration of 0.22 MPs/L was estimated, primarily dominated by blue polyethylene terephthalate fibers. The distribution of floating MPs suggests that they tend to accumulate within the semi-enclosed Sechura Bay regardless of the sampling season. This behavior may be explained by local surface currents in the bay, which flow inwards and exhibit vorticities that could entrap MPs. Future studies are suggested to investigate the trajectory and fate of floating MPs within semi-enclosed areas. On the other hand, the impact of floating MPs on the trophic chain of coastal marine protected areas requires further research.

Nanoplastic-Induced Liver Damage Was Alleviated by Maltol via Enhancing Autophagic Flow: An In Vivo and In Vitro Study

In recent years, there has been a growing concern regarding health issues arising from exposure to nanoplastics (Nps) in the natural environment. The Nps bioaccumulate within the body via the circulatory system and accumulate in the liver, resulting in damage. Previous studies have demonstrated that maltol, derived from red ginseng (Panax ginseng C.A. Meyer) as a Maillard product, exhibits hepatoprotective effects by alleviating liver damage caused by carbon tetrachloride or cisplatin. In order to explore the specific mechanism of maltol in improving hepatotoxicity induced by Nps, mice exposed to 100 mg/kg Nps were given maltol at doses of 50 and 100 mg/kg, respectively. The results showed that Nps induced an increase in the levels of liver apoptotic factors BAX and cytochrome c, a decrease in the levels of the autophagy key gene LC3 II/I, and an increase in P62. It also caused oxidative stress by affecting the Nrf2/HO-1 pathway, and a decrease in GPX4 protein expression suggested the occurrence of ferroptosis. However, treatment with maltol significantly improved these changes. In addition, maltol (2, 4, and 8 μM) also protected human normal liver L02 cells from Np (400 μg/mL)-induced damage. Our data suggest that maltol could ameliorate Np-induced L02 cytotoxicity by reducing autophagy-dependent oxidative stress, exhibiting similar protective effects in vitro as in vivo. This study helps shed light on the specific molecular mechanism of Np-induced hepatotoxicity. For the first time, we studied the protective effect of maltol on Np-induced liver injury from multiple perspectives, expanding the possibility of treatment for diseases caused by environmental pollutants.

Macrolitter and microplastics along the East Pacific coasts - A homemade problem needing local solutions

The East Pacific (EP) region, especially the central and southern EP, has been fairly less studied than other world's regions with respect to marine litter pollution. This comprehensive literature review (257 peer-reviewed publications) showed that both macrolitter (mostly plastics) and microplastics tend to accumulate on EP shorelines. Moreover, they were also reported in all the other compartments investigated: sea surface, water column, seafloor and 'others'. Mostly local, land-based sources (e.g., tourism, poor waste management) were identified across the region, especially at continental sites from low and mid latitudes. Some sea-based sources (e.g., fisheries, long-distance drifting) were also identified at high latitudes and on oceanic islands, likely enhanced by the oceanographic dynamics of the EP that affect transport of floating litter. Our results suggest that effective solutions to the problem require local and preventive strategies to significantly reduce the levels of litter along the EP coasts.

Fragmented marine plastics as the prevalent litter type on a small island beach in the Adriatic

The issue of plastic pollution has dramatically intensified in the recent years. Our study investigates extensive plastic contamination of a sandy beach on a small Adriatic island. The beach was sampled on three occasions, in 2013, 2020 and 2022, using 1 m2 quadrats placed along the lower and upper strandlines, resulting in average litter concentrations of 385 ± 106, 1095 ± 522 and 129 ± 37 item m-2, respectively. The lower size limit of collected litter was 1 mm, thus including large microplastics. Plastic fragments (49-74 %) and plastic pellets (15 %-37 %) were predominant litter categories. The proportion of fragments is significantly higher during the tourist season with a more intensive cleaning regime (April-October), as opposed to the off-season (November-March). Fisheries and aquaculture litter was identified as a relevant source of pollution. More research is needed in the future into the microplastics smaller than 1 mm.

Dynamic Stomach Model-Capillary Electrophoresis-ICPMS for Evaluation of Release and Transformation Behaviors of Arsenic Species from Microplastics during Digestion

Microplastics (MPs) can act as carriers of environmental arsenic species into the stomach with food and release arsenic species during digestion, which threatens human health. Herein, an integrated dynamic stomach model (DSM)-capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICPMS) is developed for online monitoring of the release and transformation behaviors of arsenic species loaded on MPs (As-MPs) in the simulated human stomach. The 3D-printed DSM with a soft stomach chamber enables the behaviors of gastric peristalsis, gastric and salivary fluid addition, pH adjustment, and gastric emptying (GE) to be controlled by a self-written program after oral ingestion of food with As-MPs. The gastric extract during digestion is introduced into the spiral channel to remove the large particulate impurity and online filtered to obtain the clarified arsenic-containing solution for subsequent speciation analysis of arsenic by CE-ICPMS. The digestion conditions and pretreatment processes of DSM are tracked and validated, and the release rates of As-MPs digested by DSM are compared with those digested by the static stomach model and DSM without GE. The release rate of inorganic arsenic on MPs is higher than that of organic arsenic throughout the gastric digestion process, and 8% of As(V) is reduced to As(III). The detection limits for As(III), DMA, MMA, and As(V) are 0.5-0.9 μg L-1 using DSM-CE-ICPMS, along with precisions of ≤8%. This present method provides an integrated and convenient tool for evaluating the release and transformation of As-MPs during human gastric digestion and provides a reference for exploring the interactions between MPs and metals/metalloids in the human body.

Microplastic contamination in filter-feeding oyster Saccostrea cuccullata: Novel insights in a marine ecosystem

Microplastic (MP) pollution has become a pressing global concern. Oysters are well-known filter feeders who ingest food by filtering microscopic particles suspended in the surrounding water. Along with organic matter, filter-feeding also causes accidental ingestion of MP by oysters. Hence, the aim of the current investigation is to understand the MP contamination in filter-feeding oysters. A total of 500 specimens of oyster Saccostrea cuccullata collected from the intertidal zone of five sampling locations on the Gujarat coast, India. Specimens underwent analysis following established protocols. Each specimen was found to exhibit MP contamination, showing an abundance of 2.72 ± 1.98 MPs/g. A negative relationship was found between shell length and MP abundance. Predominantly, fibers were documented across all study sites. Black, blue, and red-colored MPs with 1-2 mm sizes were most dominant. MP polymer composition was identified as polyethylene terephthalate and polypropylene. Findings provide baseline information on levels of MPs contamination, which can be used to monitor future effects of MP pollution.

Toxicological Research on Nano and Microplastics in Environmental Pollution: Current Advances and Future Directions

This review explains the sources of nanoplastics (NPs) and microplastics (MPs), their release, fate, and associated health risks in the aquatic environment. In the 21st century, scientists are grappling with a major challenge posed by MPs and NPs. The global production of plastic has skyrocketed from 1.5 million tons in the 1950s to an astonishing 390.7 million tons in 2021. This pervasive presence of these materials in our environment has spurred scientific inquiry into their potentially harmful effects on living organisms. Studies have revealed that while MPs, with their larger surface area, are capable of absorbing contaminants and pathogens from the surroundings, NPs can easily be transferred through the food chain. As a result, living organisms may ingest them and accumulate them within their bodies. Due to their minuscule size, NPs are particularly difficult to isolate and quantify. Furthermore, exposure to both NPs and MPs has been linked to various adverse health effects in aquatic species, including neurological impairments, disruption of lipid and energy metabolism, and increased susceptibility to cytotoxicity, oxidative stress, inflammation, and reactive oxygen species (ROS) production. It is alarming to note that MPs have even been detected in commercial fish, highlighting the severity of this issue. There are also challenges associated with elucidating the toxicological effects of NPs and MPs, which are discussed in detail in this review. In conclusion, plastic pollution is a pressing issue that governments should tackle by ensuring proper implementation of rules and regulations at national and provincial levels to reduce its health risks.

Microplastics abundance, distribution and composition in surface waters, sediments and fish species from Amir-Kalayeh Wetland, Northern Iran

Microplastics (MPs) pollution is considered as a globally pervasive threat to aquatic ecosystems and many studies reported this pollution in different aquatic ecosystems. However, studies on MPs pollution in wetlands are still scarce. Therefore, the aim of present study was to investigate the presence of MPs in the surface water, sediment and different fish species of Amir-Kalayeh wetland, Northern Ian. Surface water and sediment samples were collected from six stations during June to July 2022. Moreover, the gills and gastrointestinal tract (GIT) of 54 fish specimens belonging to four species including Cyprinus carpio, Tinca tinca, Esox lucius and Silurus glanis were analysed. MPs were detected in all samples with an average of 2.15 ± 1.98 items/m3 for surface water, 51.66 ± 32.20 items/kg dry weight for sediments, 0.17 ± 0.17 items/individual for fish GIT and 0.12 ± 0.12 items/individual for fish gills. There was no significant relationship between MPs abundance in surface waters and sediments as well as between MPs abundance in environmental matrices and fish (P > 0.0.5). In terms of feeding habit, no significant differences were observed between the number of MPs found in omnivorous and carnivorous fish species (P > 0.05). Moreover, no significant relationship was detected between the MPs abundance in fish tissues and body size (P > 0.05). MPs were mainly fibers, mostly transparent, and in a range size of 70-5000 µm. The dominant MPs type was nylon in all samples. This study will help increase our knowledge about MPs pollution in inland freshwater systems and suggests that management policies take essential steps to reduce this insidious problem in freshwater ecosystems.