Microplastics in the marine environment

A critical review on the migration, transformation, sampling, analysis and environmental effects of microplastics in the environment

As emerging pollutants, microplastics have recently received considerable attention owing to detection in various organisms and environments. Mass production and widespread use of plastic products increase their potential risks to humans owing to their persistent, mobile, and toxic properties. Numerous methods have been used to identify and quantify the various forms of microplastics, however, unified standards do not exist. In this review, we systematically summarize the sources, migration, transformation, and analytical methods for microplastics in diverse ecosystems, particularly the most recent sampling and identification techniques. Additionally, the environmental effects and health hazards of microplastics on aquatic and terrestrial systems, as well as human beings are discussed. We also present management strategies for reducing microplastics in a broader social and policy context. This review aims to provide an overview of the migration, transformation, sampling, analysis, and environmental effects of microplastics, which addresses knowledge gaps in microplastic pollution and provides proposals for key research gaps.

Marine micro(nano)plastics toxicology: Knowledge gaps and perspectives

Micro(nano)plastics (MNPs) have emerged as pervasive contaminants widely documented across diverse environmental systems. Concerns regarding their environmental and human health impacts have escalated. Numerous studies have explored various aspects of the environmental toxicology of MNPs, particularly their effects on marine biota. However, significant knowledge gaps persist, hindering the ability to conduct effective environmental risk assessments for these plastic particles. This perspective highlights the critical aspects of MNPs' environmental toxicology that require advanced technological approaches to track and quantitatively reveal their subtle yet profound impacts. These aspects include ecological contexts extending beyond traditional toxicology, MNPs kinetics (uptake, transformation, and accumulation), modeling for simulating these processes under various scenarios, and identification of specific biomarkers associated with MNPs exposure. The establishment of environmental quality criteria for MNPs, if deemed necessary, will depend heavily on a comprehensive understanding of their behavior, toxicity, and ecological consequences. Ultimately, a deeper understanding of MNPs' environmental toxicology is essential for safeguarding both ecological integrity and human health in the face of this growing global challenge.

Estuarine plastic dynamics: Analyzing export patterns from a typical semi-enclosed bay in Asia

Semi-enclosed estuarine systems are recognized as hotspots for microplastic (MP) pollution, yet their export dynamics remain poorly understood. This study investigates the distribution of microplastics (<5 mm) and macroplastics (>5 mm) in Sanya Bay, a typical semi-enclosed bay in southern China. Based on 45 surface water samples, MP concentrations ranged from 0.298 to 4.010 items/m³ (mean: 1.628 ± 1.055), significantly higher than macroplastics (mean: 0.109 ± 0.338 items/m³). Most particles were fragments smaller than 5 mm, dominated by white, green, and transparent colors. The main polymers identified were polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET). A "dual-center" pattern was observed: low-density plastics (e.g., PP, PE) accumulated near river mouths and offshore islands, while high-density plastics (e.g., PET, PVC) settled in estuarine zones. Principal Coordinate Analysis (PCoA) revealed spatial clustering across estuarine, coastal, and offshore areas, influenced by land-based inputs, human activity, and hydrodynamic transport. This study provides new insights into plastic transport mechanisms in semi-enclosed bays and highlights the importance of integrating plastic properties with environmental forces. The findings support targeted pollution management in similar coastal environments.

Promoting LDPE microplastic biodegradability: The combined effects of solar and gamma irradiation on photodegradation

Low-Density Polyethylene (LDPE) is non-biodegradable and breaks down into microplastics (MP) when exposed to sunlight and weathering. This poses a threat to ecosystems, contributing to the micropollutants found in urban treated wastewater. Our study aimed to investigate the effects of solar and gamma irradiation on the biodegradability of LDPE MP. We pretreated them with simulated solar irradiation without (photolysis) and with (photocatalysis) TiO2 nanoparticles followed by gamma irradiation, leading to the appearance of cracks and roughness on the surface. Simultaneously, thermal stability decreased, and the carbonyl index and crystallinity increased, indicating oxidation and chain scission. Aerobic biodegradability was measured in a static respirometer at 58ºC, using green compost as inoculum, and proved to be effective for screening biodegradability of the pretreated LDPE. The combination of photocatalysis and gamma irradiation produced a synergistic effect on photodegradation, making it the most effective method for promoting biodegradation, revealed by the increased specific oxygen uptake rate (SOUR), which is expressed as millimoles O2 per mol of carbon per hour, and the greatest biodegradation kinetics constant (kO2=0.0178 h-1). The primary mechanism driving biodegradation involved the formation of carbonyl groups, which initiated biological activity.

Colonization time of plastisphere drives the dynamics of organic carbon stability and microbial communities in seagrass bed sediments

Microplastic (MP) pollution in seagrass bed ecosystems has emerged as a significant global concern. However, the effects of plastisphere formation on organic carbon pools and microbial communities in these ecosystems remain unknown. We conducted a 56-day microcosm incubation experiment to study the dynamic changes in physicochemical characteristics, organic carbon fractions and stability, and bacterial community structure in seagrass bed sediments during the plastisphere formation process for polystyrene (PS) and polylactic acid (PLA). The results revealed significant weathering and biofilm formation on both PS and PLA. MPs altered the microbial community structure in seagrass bed sediments, leading to species turnover. Colonization time emerged as the key factor driving microbial community assembly, with ecological processes shifting from dispersal limitation to ecological drift in the plastisphere, while sediments maintained dispersal limitation as the dominant process. The formation of the plastisphere significantly influenced seagrass bed sediment microbial carbon (MBC) and organic carbon pool stability. MPs weathering negatively correlated with sediment properties but positively correlated with microbial communities, jointly modulating carbon pool stability. This study provided a new insight into the potential risks posed by MPs to carbon cycling and the ecological functioning of seagrass bed ecosystems.

Characterisation of plastic debris (macro-, meso-, and microplastics) from stranded alcids in southern Spain

Plastic pollution has become a major issue for marine ecosystems. Seabirds are particularly vulnerable to this pollution and are very good indicators of the ecological state of marine ecosystems. This study aims to analyse the presence of plastics in the digestive tracts of two seabird species: the Atlantic puffin (Fratercula arctica) and the razorbill (Alca torda), collected along the Andalusia coast in Southern Spain. A total of 123 carcasses were collected during the autumn and winter seasons of 2022-2024. The results showed a significantly higher presence of plastics in Atlantic puffin (65.0 %) compared to razorbill (18.4 %). The mean number of plastics per puffin was 2.50 ± 2.75, while per razorbill was 0.31 ± 0.94. The predominant type of ingested plastic was fibres in both Atlantic puffin (38.0 %, n = 19) and razorbill (40.6 %, n = 13), with an average size of 1.58 ± 0.74 mm and 2.13 ± 1.98 mm, respectively. The predominant colour was black in both species (22.0 % in puffin and 46.9 % in razorbill), and polyethylene (39.5 %) was the most common plastic polymer, consisting of highly fragmented particles with low levels of adhering heavy metals. This study supports the growing concern about plastic pollution in marine environment, showing that alcid populations are ingesting plastics, potentially threatening these vulnerable species.

Deciphering the source contribution of microplastics in the glaciers of the North-Western Himalayas

Microplastics (MPs) and nanoplastics (NPs) have been largely studied in marine environments, but there lies a significant gap in assessing their occurrence and impacts in glacier environments. This study investigates the occurrence and pollution risks of MPs and NPs in glaciers, suspended air, and dry deposition across the northwestern Himalayas. MPs concentration ranged from 1000 particles m-3 in Kolahai glacier to 151000 particles m-3 in Thajwas glacier. In suspended air, MPs occurred at 5 particles m-3, while dry deposition samples showed a concentration ranging from 1 to 13 particles m-2 d-1. Dynamic light scattering (DLS) confirmed the presence of NPs in all glaciers, with sizes varying between 31 and 689 nm in Thajwas glacier and 360-953 nm in Harmukh glacier. HYSPLIT modelling revealed that air masses reaching Himalayan glaciers predominantly originate from global sources (75 %). The pollution load index (PLI) ranged from 3.9 (hazard category I) to 40 (hazard category IV), indicating moderate to excessive pollution of glaciers. While as polymer hazard index (PHI) ranged from 10 (hazard category II) to 1987 (hazard category V), indicating medium to extreme danger due to presence of polyvinyl chloride (PVC) and polyacrylonitrile (PAN). The presence of MPs and NPs accelerate glacier melting due to their light absorbing properties highlighting need for further studies.

Insights into soil microbial assemblages and nitrogen cycling function responses to conventional and biodegradable microplastics

Biodegradable microplastics (MPs) are proposed as sustainable alternatives to conventional MPs, yet their distinct effects on soil microbial communities and ecological functions remain insufficiently understood. This study compares the impacts of biodegradable polylactic acid (PLA) and conventional polyvinyl chloride (PVC) MPs on soil microbial assemblages and nitrogen cycling. Fluorescein diacetate hydrolase (FDAse) activity was temporarily stimulated by 2 % (w/w) PLA and PVC MPs, while 7 % (w/w) PVC MPs initially inhibited FDAse activity before promoting it. PLA MPs (2 % and 7 %, w/w) dramatically reduced bacterial diversity and altered community structure, enriching genera such as Nocardioides, Arthrobacter, Agromyces, Amycolatopsis, Saccharothrix, and Ramlibacter, known for degrading complex compounds. Conversely, PVC MPs (2 % and 7 %, w/w) showed minimal influence on bacterial diversity, with only temporary structural shifts at high concentrations (7 % w/w). Network analysis revealed greater microbial complexity with PLA MPs, where MPs-degrading taxa emerged as keystone species. PLA MPs at both concentrations notably increased the abundance of nitrogenase iron protein subunit H gene (nifH) and nitrogen-fixing bacteria, such as Bradyrhizobium, while also sustaining ammonia monooxygenase subunit A gene (AOB amoA) effects up to day 90. At higher doses (7 % w/w), PLA MPs enriched copper-containing nitrite reductase gene (nirK) and cytochrome cd1 nitrite reductase gene (nirS) abundance, boosting denitrifiers like Cupriavidus, Pseudarthrobacter, and Ensifer. In contrast, PVC MPs showed short-term effects on nitrogen cycling function. These findings have important implications for promoting sustainable agriculture and managing the environmental risks posed by MPs in soil ecosystems.

Distribution characteristics and transport processes of biodegradable microplastics in the Seto Inland Sea, Japan

Microplastics (MPs) pollution is a prevalent environmental problem that affects ecosystems globally. Despite the growing research on the environmental effects of MPs, a significant research gap remains in understanding the differences of environmental behavior and distribution patterns between biodegradable MPs and traditional MPs. Using a three-dimensional hydrodynamic model and treating MPs as tracers with vertical velocity, this study simulated the transport of positively, neutrally, and negatively buoyant biodegradable MPs from rivers. The results show that positively buoyant MPs have significant seasonal variations and are mainly distributed in the surface layer. Neutrally buoyant MPs are distributed in all water depths, with a high (low) concentration in the eastern (western) Seto Inland Sea (SIS), characterized by winter mixing and summer stratification. Negatively buoyant MPs accumulate in the sediments and exhibit lower concentrations in seawater. Positively and neutrally buoyant MPs mainly outflow from the SIS into the Pacific Ocean, whereas negatively buoyant MPs hardly leave the SIS and are primarily deposited and degraded near river mouths. A settling velocity of -10-6 to -5×10-5 m s-1 (downward) greatly affects the concentration of MPs in seawater. However, large upward and downward velocities outside this range do not result in pronounced changes. Compared with traditional MPs, biodegradable MPs are less environmentally persistent by not accumulating in sediments and keeping a low concentration there, which contributes to the reduction of transport flux of MPs to the Pacific Ocean.

Characterization and risk assessment of microplastics accumulated in sediments and benthic molluscs in the mangrove wetlands along the south-west coast of India

In the present study, occurrence and characteristics of microplastics in mangrove sediments and benthic molluscs viz., black clam (Villorita cyprinoides), yellow clam (Meretrix casta), mangrove horn snail (Telescopium telescopium) and brackish water snail (Neripteron violaceum) were studied from mangrove habitats of Vembanad Lake, the largest estuary and a Ramsar site on the south-west coast of India. The average microplastic abundance in mangrove sediments varied between 235 ± 49.5 and 1414 ± 182 items/kg dry weight, with an average concentration of 673.45 ± 365.05 items/kg dry weight, which was at a relatively higher level compared to other mangrove regions of India. The highest abundance was recorded for gastropod T. telescopium (38.5 ± 11.48 items/individual). The predominant shape, colour and size of microplastic in mangrove sediment and molluscs were fragments, black and < 500 μm, respectively. The major polymers identified were polyethylene and polypropylene in sediments and molluscs. Higher values of ecological risk indices (Microplastic index and Microplastics diversity integrated index) indicated a severe microplastic pollution risk for the molluscs in the mangroves. The high bio-accumulation factor also highlights the possibility of using these species as bioindicators of plastic pollution in mangrove habitats. The results of the present study could be useful to prepare effective management strategy to minimize plastic pollution load in mangrove habitats.

Baseline assessment of microplastics pollution in beach sediments along tropical coastline (Kuala Langat, Malaysia)

This study examines the occurrence, physical characteristics (size, colour, and shape), and polymer compositions of microplastics (MPs) in beach sediments along the Kuala Langat coastline impacted by tourism and fishing activities. Microplastics particle were isolated using density separation, characterized using microscopy and Spectroscopy technique. Microplastic concentrations ranged from 0.01 to 0.21 particles/g in tourist sites and 0.01 to 0.03 particles/g in non-tourist sites, indicating significantly higher MP pollution in tourism-affected areas. The longest MP particle (4951.5 μm) was found in a non-tourist area, while the shortest (84.7 μm) was detected on a tourist beach. Fragment-shaped MPs (82.40 %) were the most dominant, exhibiting a variety of colors and diverse plastic sources. Polypropylene, polyethylene, and polystyrene comprised 80 % of the detected polymers, suggesting that single-use plastics contribute substantially to MP pollution in both sampling sites. These findings provide critical insights for targeted strategies for plastic waste management in tropical coastal areas.

Microplastic occurrence in 21 coastal marine fish species from fishing communities on Viti Levu, Fiji

Microplastic contamination in fish is a growing concern in Fiji's marine ecosystems, yet comprehensive data across diverse species and fishing grounds remain scarce. This study analyses microplastic ingestion in 184 fish from 21 species across three Viti Levu communities (Galoa, Silana, Yadua). Microplastics were found in 74 % of fish, with 399 particles identified: fibers (66 %), fragments (20 %), and films (14 %). Dominant polymers included polyethylene (20 %), polypropylene (19 %), polyethylene terephthalate (18 %), nylon (16 %), and nitrile (8 %). The average concentration (2.17 ± 0.16 particles/individual (mean ± standard error)) was lower than in urbanized Fijian regions, but occurrence frequency was higher. Species-level variations in microplastic presence and particle characteristics highlight contamination risks in coastal fishing grounds. This dataset, the largest of its kind for Fiji, establishes a critical baseline for monitoring plastic pollution, supporting sustainable fisheries management and regional mitigation strategies.

Concentration-dependent effects of polystyrene microplastics on methanogenic activity and microbial community shifts in sewer sediment

Microplastics (MPs) are emerging environmental contaminants that interfere with microbial processes, yet their effects on methanogenesis in anaerobic systems remain insufficiently understood. This study investigates the impact of polystyrene microplastics (PS-MPs) on methanogenesis, microbial community structure, and metabolic pathways in simulated sewer sediment systems, with exposure concentrations of 5, 50, and 250 mg·L-1. The results revealed a concentration-dependent effect of PS-MPs on methanogenesis: a 222.2 % increase at 5 mg·L-1, and 72.2 % and 88.9 % increases at 50 mg·L-1 and 250 mg·L-1, respectively, indicating a non-linear response. PS-MPs exposure enhanced coenzyme F420 (F420) activity, a key indicator of methanogenic activity, but also inhibited methyl coenzyme M reductase (Mcr), disrupting critical methanogenic pathways. At lower concentrations, PS-MPs promoted the abundance of hydrogenotrophic methanogens, whereas higher concentrations suppressed overall methanogenic activity. Furthermore, PS-MPs had a dose-dependent effect on CH4 oxidation, influencing the structure of methanotrophic communities. These findings establish a clear dose-response relationship between PS-MPs concentration and CH4 dynamics in anaerobic systems, highlighting the complex role of microplastics in methanogenesis and microbial interactions. This research provides valuable insights into the environmental implications of microplastics in wastewater systems and their potential impacts on biogas production and CH4 mitigation, aligning with the objectives of environmental bioengineering and sustainable waste management.

Quantification of microplastics in agricultural soils by total organic carbon -solid sample combustion analysis

Accurate quantification of microplastics (MPs) in soils is a significant challenge due to the complex nature of the organo-mineral matrix. Fine mineral particles and organic matter often interfere with the efficiency of extraction, identification and quantification of MPs from soils. Here, an optimized MP extraction and quantification method is proposed, using total organic carbon analyser-solid sample combustion unit (TOC-SSM) analysis. The approach entails a field survey, digestion of organic matter by Piranha solution, density separation, and quantification. This method achieves a high total recovery rate of 97.39 ± 14.25 (SE) % for particles sized between 300 and 600 µm, and 94.80 ± 13.48 (SE) % for particles less than 300 µm with spiked soil as samples. The optimised method is then applied to strawberry farm soils that use plastic mulch films to quantify MP contamination levels. Our results indicate MP concentrations of 12.24 ± 3.65 (SE) mg kg-1 (for particles of 300-2000 µm in size) and 2.62 ± 0.66 (SE) mg kg-1 (for particles smaller than 300 µm). With improved simplicity and the ability to provide the actual weight of plastics for the extraction and quantification of MPs, this work offers a potential approach for assessing low-density plastics in the northeastern Australian agricultural soils with a dominant MP contamination, specifically polyethylene (PE).

Microplastics under siege: Biofilm-forming marine bacteria from the microplastisphere and their role in plastic degradation

Microplastics, a complex category of pollutants containing microorganisms and toxins, pose a significant threat to ecosystems, affecting both biotic and abiotic elements. The plastisphere's bacterial community differs significantly from nearby habitats, suggesting they may significantly contribute to the degradation of plastic waste in the ocean. This study evaluated the diversity of culturable bacterial populations attached to the microplastics in the coastal zones of the A&N Islands and their potential for plastic degradation. Three A&N Islands beaches were surveyed for microplastics. Low-density polyethylene (LDPE) was the most abundant polymer found, followed by Acryl fibre, polyisoprene etc. A total of 24 bacterial isolates were chosen based on their morphological traits and underwent the initial screening processes. With the highest degrading activity (10.79 %), NIOT-MP-52 produced noteworthy results. NIOT-MP-25 (5.07 %), NIOT-MP-43 (3.78 %), NIOT-MP-61 (3.51 %), and NIOT-MP-82 (3.36 %) were the next most active strains. Strain NIOT-MP-52, selected for its superior degradation efficiency, underwent further screening and analysis using FT-IR, SEM, AFM, and DSC. Variations in infrared spectra indicated the breakdown of LDPE while SEM and AFM analyses showed bacterial attachment, roughness, grooves, holes, and pits on the LDPE surface. DSC provided thermal analysis based on the biodegradation potential of the bacterial strain targeting LDPE sheets. These findings highlight the ability of marine bacteria to efficiently degrade microplastics and utilize plastics as an energy source, emphasizing their importance in future plastic waste management.

Trophic-transferred hierarchical fragmentation of microplastics inducing distinct bio-adaptations via a microalgae-mussel-crab food chain

Microplastics (MPs) are alarming social issues owing to their detrimental influences on both ecology and human health. Although MPs retained in low-trophic organisms are assumed to be transferred to high-trophic organisms via the food chain, concrete knowledge about the physical-chemical alterations of MPs via trophic transfer and the impact of trophic-transferred MPs on organisms remains scarce. Here, we established a three-tiered (microalgae-mussel-crab) trophic-transfer model to systematically investigate the bio-accumulation and distribution of polyethylene MPs (PE-MPs, 10-45 μm), and subsequent induction of antioxidant defenses in marine organisms with pivotal ecological and economic status at each trophic level. Results demonstrated that microalgae's growth and quality as feeds were hampered due to attachment to PE-MPs, whose physical-chemical properties were hence altered. This affected the intake and occurrence of PE-MPs in mussels, where PE-MPs were initially fragmentized. Following mussel-crab transfer, further fragmented PE-MPs in crabs resulted in stronger internalization and active internal transport among tissues. Despite successful antioxidation observed in both consumers, severer stress was posed on tissues in charge of metabolism and detoxification, leading to serious DNA damage. Overall, hierarchical fragmentation can increase internalization and bio-transportation of MPs via trophic transfer leading to longer retention and stronger capacity across biological barriers, which is speculated to pose further risks to higher-trophic organisms (e.g., humans).

Distribution and diversity of microplastics along the aquatic food web in the largest mangrove reserve of China

Knowledge of microplastics (MPs) in consumers at different trophic levels and with different feeding strategies in mangroves is essential to evaluate pathways and ecological effects from exposure to MPs. We conducted a comprehensive study on the distribution of MPs along the food web in the largest natural mangrove reserve in China, and applied diversity index of MPs, D'(MP), in terms of color, size, shape and type, to investigate complexity of MPs through the trophic cascades. The highest abundance of total MPs occurred at 5.7 ± 2.6 items/individual in fish, followed by 4.8 ± 1.9, 3.2 ± 0.5, 2.2 ± 0.9 items/individual in crabs, bivalves and shrimps, respectively. There was a correlation between the abundance of MPs in the gastrointestinal tracts (GITs) or soft tissues of organisms and trophic levels (r = 0.47, p < 0.01), while microplastic abundance were also correlated with body wet weights. The abundance and diversity of MPs in mangrove organisms were influenced by their feeding behaviors and living habitats, as consumers through indirect ingestion had significantly higher abundance of MPs than discriminate feeders. For MPs in their GITs, crabs had the highest shape D'(MP), but the lowest size D'(MP) and color D'(MP), while fish had highest color D'(MP), but significantly lower shape D'(MP). Our application of diversity index of MPs to mangrove ecosystem for the first time reveals a rather complicated distribution of MPs along the aquatic food web, demonstrating an urgent need for measures to reduce the discharge of MPs into mangrove and develop a remediation strategy.

Microplastics and nanoplastics detection using flow cytometry: Challenges and methodological advances with fluorescent dye application

Flow cytometry (FC) enables the precise quantification of specific types of microparticles and larger nanoparticles (>200 nm) in liquid media. Initially developed for biological applications, this technique has recently been adapted to the environmental field for the measurement of microplastics and nanoplastics (MNPs). Nile Red, a fluorochrome extensively used in MNP analysis due to its effectiveness and accessibility, has been applied to significantly enhance the sensitivity and specificity of MNP detection of this technique. Additionally, flow cytometry offers the advantage of automated detection, allowing the quantification of smaller particles, including those under 1 µm, which are often missed by traditional spectroscopic methods. However, despite its promise, the presence of undissolved dye in aqueous media presents a significant challenge for accurate quantification. In recent years, various methodologies have been developed to overcome these limitations, including the use of co-solvents, surfactants, and pre-filtration or pre-sonication techniques to enhance quantification accuracy. This review examines recent literature on MNPs detection via FC, with a focus on technical improvements made and the remaining metrological challenges, offering insights into how this method can be further refined for future investigations.

The density of virgin, consumer and environmental plastics: An investigation using gas displacement pycnometry

Density is a fundamental property of plastics and is particularly significant in determining the transport and fate of waste plastics that enter aquatic systems. However, densities are rarely determined in the environmental literature and values employed for modelling or impacts are often unsourced or derived from secondary databases. In this study, we employ helium displacement pycnometry to determine the skeletal densities of non-porous plastics whose polymer composition had been established from manufacturer's data, resin codes or Fourier transform infrared spectrometry. Two independent, collaborative laboratories, providing measurements within 3.5 % of each other and with precisions of <1 % (as relative standard deviation), analysed a total of 42 virgin, consumer and environmental plastics consisting of ten common polymer types. Measured densities of plastics in all categories, and most notably for polybutylene terephthalate, polyethylene terephthalate, polypropylene and polyvinyl chloride, were often outside the ranges reported by a comprehensive online resource. Possible reasons for discrepancies include the occurrence of dense additives (evaluated by X-ray fluorescence analysis), the presence of inaccessible microscopic pores below a laminated surface, contamination of the main polymer by a secondary one, and structural changes on weathering. Regardless of precise causes, most results suggest that individual polymers have a broader range of densities than is generally published or considered in the literature. Accordingly, and in particular where buoyancy is critical, more precise, sample-specific measurements are recommended.

Unveiling the toxicity of micro-nanoplastics: A systematic exploration of understanding environmental and health implications

The surge in plastic production has spurred a global crisis as plastic pollution intensifies, with microplastics and nanoplastics emerging as notable environmental threats. Due to their miniature size, these particles are ubiquitous across ecosystems and pose severe hazards as they are ingested and bioaccumulate within organisms. Although global plastic production has reached an alarming 400.3 MTs, recycling efforts remain limited, with only 18.5 MTs being recycled. Currently, out of the total plastic waste, 49.6 % is converted into energy, 27 % is recycled, and 23.5 % is recovered as material, indicating a need for better waste management practices to combat the escalating pollution levels. Research studies on micro-nanoplastics have primarily concentrated on their environmental presence and laboratory-based toxicity studies. This review critically examines the sources and detection methods for micro-nanoplastics, emphasising their toxicological effects and ecological impacts. Organisms like zebrafish and rats serve as key models for studying these particle's bioaccumulative potential, showcasing adverse effects that extend to DNA damage, oxidative stress, and cellular apoptosis. Studies reveal that micro-nanoplastics can permeate biological barriers, including the blood-brain barrier, neurological imbalance, cardiac, respiratory, and dermatological disorders. These health risks, particularly relevant for humans, underscore the urgency for broader, real-world studies beyond controlled laboratory conditions. Additionally, the review discusses innovative energy-harvesting technologies as sustainable alternatives for plastic waste utilisation, particularly valuable for energy-deficient regions. These strategies aim to simultaneously address energy demands and mitigate plastic waste. This approach aligns with global sustainability goals, providing a promising avenue for both pollution reduction and energy generation. The review calls for further research to enhance detection techniques, assess long-term environmental impacts, and explore sustainable solutions that integrate energy recovery with pollution mitigation, especially in regions most affected by both energy shortages and increased plastic waste.

Long-term changes in the incidence and characteristics of plastic ingested by White-chinned Petrels

Plastic floating at sea is difficult to measure due to its high spatial and temporal variation. White-chinned Petrels Procellaria aequinoctialis are surface-foraging seabirds found in the Southern Ocean that often ingest plastic. They are susceptible to being caught accidentally on long-line fishing gear, providing carcasses that can be used to monitor changes in the incidence and characteristics of plastic floating at sea. Of the 2486 White-chinned Petrels sampled off South Africa between 1979 and 2024, 57 % contained plastic. Data were grouped into time periods to determine temporal variation while accounting for unequal yearly sample sizes. The proportion of birds containing plastic has not changed since 1979. The number of plastic items ingested increased from an average of 2 items per bird in the early 1980s to 7 in 2017-24, mainly due to an increase in the last 5 years, but there has been no change in the total mass of ingested plastic. The proportion of pellets declined from 25 % to 17 %, with the average number of pellets per bird following a similar trend until two highly impacted birds were found in 2022 and 2023, possibly reflecting recent large pellet spills at sea off South Africa. White-chinned Petrels ingest more flexible plastics (threads and films) than other petrels, potentially linked to their behaviour of scavenging behind ships. Some birds contained fibrous gastroliths, up to 20 mm in diameter. Recording plastic loads in White-chinned Petrels offers a useful method to monitor long-term changes in floating plastic at sea.

Impact of seasonal variations on microplastic accumulation and characteristics in sandy beaches of Sichang Island, the inner Gulf of Thailand

Microplastics (MPs) are pervasive environmental pollutants whose fate, transport, and ecological impacts require clarification. This study examines the abundance and characteristics of MPs (16-5000 μm) in sandy beach sediments on Sichang Island, the inner Gulf of Thailand, during the dry season and after a four-month wet season. On the western beach, exposed to monsoon winds and currents, MP abundance increased from 2295.38 ± 1227.44 pieces/kg in the dry season to 2386.63 ± 121.45 pieces/kg post-wet season. Conversely, the leeward eastern beach showed a significant decrease, from 686.29 ± 243.90 to 238.63 ± 121.45 pieces/kg. Polypropylene was the dominant polymer, with reduced variation in MP color and shape following the wet season. The proportion of smaller MPs (16-100 μm) decreased from 59 to 62 % in the dry season to 27-42 % post-wet season, while larger debris became more prevalent. These findings highlight seasonal shifts in MP accumulation and dispersal on sandy beaches influenced by hydrodynamic conditions.

A global assessment of microplastic abundance and characteristics on marine turtle nesting beaches

Sandy coastal beaches are an important nesting habitat for marine turtles and a known sink for plastic pollution. Existing methodologies for monitoring the spatiotemporal patterns of abundance and composition of plastic are, however, disparate. We engaged a global network of marine turtle scientists to implement a large-scale sampling effort to assess microplastic abundance in beach sediments on marine turtle nesting beaches. Sand samples were collected from 209 sites spanning six oceans, microplastics (1-5 mm) were extracted through stacked sieves, visually identified, and a sub-sample verified via Fourier-transform infrared spectroscopy. Microplastics were detected in 45 % (n = 94) of beaches and within five ocean basins. Microplastic presence and abundance was found to vary markedly within and among ocean basins, with the highest proportion of contaminated beaches found in the Mediterranean (80 %). We present all data in an accessible, open access format to facilitate the extension of monitoring efforts and empower novel analytical approaches.

Correcting microplastic pollution and risk assessment in Chinese watersheds

Microplastics (MPs) are emerging pollutants that are attracting attention because of their potential threats posed and their widespread presence in the environment. MP pollution in Chinese watersheds requires assessment; however, existing risk models face data-scale biases. By compiling 2,474 samples from 165 articles, we constructed a national dataset on MPs and propose a novel framework that integrates rescaled MP concentrations with MP characteristics to recalibrate MP pollution and ecological risks. The results showed that MP concentrations show substantial variability across seven orders of magnitude, and corrected data offered a more accurate representation of environmental concentrations. MP shapes, polymers, and colors differed among river basins, and population density and precipitation were important drivers of variations in MP concentrations. MP shapes, colors, and sizes that were not previously considered are now included in the risk assessment of MPs. Furthermore, 50 % of the sampling sites were in the dangerous and extremely dangerous ecological risk classes. The concentrations measured at 16.98 % of the sampling sites exceeded the risk threshold, therefore posing ecological and toxicological risks. The assessment framework may provide overall insights into the differences in MP pollution in river basins.

Chemical emissions from offshore wind farms: From identification to challenges in impact assessment and regulation

Offshore wind energy may offer many advantages: next to the aim of renewable energy production, offshore wind farms (OWFs) enable multi-purpose opportunities with nature conservation and aquaculture. OWFs may also affect the marine ecosystem. The environmental impact of OWFs is starting to be investigated regarding the effect of novel habitat introduction, underwater noise, electromagnetic fields, or exclusion of fisheries. However, the impact of chemical emissions from OWFs remains largely unknown. It is essential to account for these emissions at an early stage, to comprehensively assess the environmental impact with the objective of developing a future fit-for-purpose regulatory framework to protect the marine environment. This review compiled a literature-based list of potential OWF-related chemical emissions containing >200 organic and inorganic contaminants, including polymers. Compounds are categorised according to data source and emission type. Major gaps in assessing the impact of the compounds are identified, including challenges in environmental monitoring, numerical modelling and assessing the toxicity of individual and mixtures of chemical contaminants on marine organisms and humans consuming potential OWF aquaculture products. A risk-based prioritisation is essential to target the compounds of higher concern and overcome costs linked to assessing a wide variety of chemical contaminants. Although some countries have regulations to reduce OWF chemical emissions, standardized impact assessments or monitoring requirements for OWF-based chemical contaminants have not been established. This stresses the importance of providing more detailed information on occurrence, distribution and impact of OWF chemical emissions as an essential step towards sound ecosystem-based management of OWF installations.

Effect of microplastic binding capacity on antioxidant and immune responses of Korean rockfish Sebastes schlegeli in a co-exposure environment with microplastics and Streptococcusiniae

Korean rockfish (Sebastes schlegeli) aquaculture, which predominantly occurs in coastal regions, encounters challenges such as reduced productivity owing to microplastics and bacterial contamination. Microplastic adsorb bacteria and accumulates in fish, inducing alterations in antioxidant and immune responses. Numerous studies have examined the interaction between microplastics and external pollutants such as heavy metals and physiological changes in fish; however, studies on the effects of combined exposure to microplastics and bacteria on physiological changes in fish remain limited. Therefore, we investigated the effects of combined exposure to microbead (MB) and Streptococcus iniae (S. iniae) on the antioxidant and immune responses of Korean rockfish. Korean rockfish were exposed to single and combined environments of 0.2 μm MB at 5 and 50 beads/L and S. iniae at 1 × 105 and 1 × 107 CFU/mL for 5 days. MB accumulation in gill and intestine tissues was examined, and copy number changes of S. iniae in liver and spleen tissues were analyzed. The mRNA expression levels of antioxidant enzymes (SOD and CAT) and immune-related genes (IL-1β, IL-6, CCL25, and TNF-α) were analyzed in the liver tissue, while changes in plasma MDA and lysozyme levels were evaluated as an additional immune-related factor. Combined exposure to high concentrations of MB and S. iniae increased the accumulation of MB and the copy number of S. iniae than that of a single exposure. This also increased the mRNA expression of antioxidant enzymes and immune response genes. These results indicate that the accumulation of MB in Korean rockfish, depending on its concentration, can bind with S. iniae, inducing changes in the copy number of S. iniae and affecting antioxidant and immune responses. This study is expected to provide fundamental academic data for understanding the physiological and immunological responses of marine organisms exposed to the combined effects of MB and S. iniae.

Microbial plankton uptake enhances the degradation of a biodegradable microplastic

The use of biodegradable plastics as an alternative to conventional non-degradable synthetic polymers is gaining market to reduce plastic pollution, however, their biodegradability is not unconditional. In this study, we hypothesized that planktonic protists (nanoflagellates and ciliates) increase the degradation of the biodegradable PLGA (poly(lactic-co-glycolic) acid) due to particle uptake. We conducted uptake and degradation experiments using PLGA microspheres of 4.9 ± 2.8 μm diameter and the microbial planktonic community from the Baltic Sea. We found that planktonic protists ingested PLGA of different sizes, with ciliates displaying higher clearance rates and ingesting larger particles compared to nanoflagellates. In addition, we observed a more pronounced decrease in PLGA concentration and particle size over time in the presence of seawater containing microbial plankton compared to a control with only ultrapure water, suggesting that the presence of these organisms increases the rate of degradation of PLGA in marine ecosystems. Altogether, these results indicate that microbial plankton enhances the degradation of biodegradable microplastics like PLGA, specifically through rapid uptake by planktonic protists. These findings highlight the role of particle ingestion by planktonic protists in the fate of the so-called biodegradable plastics when they enter aquatic 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.

Microplastics in the deep: Suspended particles affect the model species Mytilus galloprovincialis under hyperbaric conditions

Microplastics (MPs) are small plastic particles that result from the degradation of bigger fragments or introduced into the environment as primary particles. Their reduced size makes them available for ingestion by marine organisms, particularly in subtidal and deep-sea environments, which represent the largest sinks for MPs in the ocean. However, there is a lack of data regarding the effects of MPs in subtidal and deep-sea ecosystems. Thus, the present study aimed to assess the effects of MPs under hyperbaric conditions. Juvenile mussels, Mytilus galloprovincialis, were exposed to three concentrations of polyethylene MPs: 0.1, 1 and 10 mg/L, in a mixture of sizes (38-45, 75-90 and 180-212 μm), at different pressures: 1, 4 and 50 Bar, for 96 h. After exposure, the filtration rate, biochemical markers of oxidative stress and transcriptomic profile were analyzed to assess the effects of MPs. Results indicate that MPs affected functional endpoints, with a significant decrease in the filtration rate of mussels exposed to MPs at 1 mg/L and higher. Similarly, all tested oxidative stress biomarkers were affected in a treatment, concentration and pressure-dependent manner. RNA-seq analysis performed in organisms exposed to 1 mg/L of MPs at 4 Bar identified several affected signaling pathways (430 differentially expressed genes) including cellular senescence, the MAPK, RAS PI3K-Akt signaling pathways, apoptosis, among others. Overall, the results here presented corroborate the hypothesis that MPs affect exposed organisms under short-term hyperbaric conditions. These findings highlight the need to study MPs effects in subtidal and deep-sea taxa and address, in future studies, combined effects with other stressors such as contaminants that might be sorbed to the surface of the particles. These findings also indicate that improving hazard assessment of MPs under hyperbaric conditions is paramount to support risk assessment and the implementation of mitigation strategies.

Plastic and rubber polymers in urban PM10 by pyrolysis-gas chromatography-mass spectrometry

Microplastics, including tyre and road wear particles, have been detected in every environmental compartment in both urban and remote areas. However, their contribution to atmospheric particulate matter is still sparsely explored. These airborne micro- and nanosized particles are continuously inhaled and pose risks to the environment and public health. The objectives of this study were to develop and validate a thermoanalytical method for the quantification of microplastics in urban particulate matter. Aerosol particles smaller than 10 µm in aerodynamic diameter (PM10) were sampled at the kerbside in Helsinki, Finland, during spring 2024. The samples were pretreated by homogenization and thermal desorption prior to chemical analysis by micro-furnace pyrolysis-gas chromatography-mass spectrometry. The developed method was validated in terms of selectivity, limits of quantification, linear range, trueness, precision, and measurement uncertainty. Instrument quantification levels were 8-270 ng. Expanded measurement uncertainties were 25-30% and 50-70% for the studied tyre wear rubbers and thermoplastics, respectively. Polyethylene, polyethylene terephthalate, polypropylene, polystyrene, and tyre and road wear particles were detected in urban PM10 samples, and their sum accounts for 1-3% of total PM10. These results represent the level of airborne microplastic particles to which people can be exposed in urban environments.

Preliminary investigation of the spatio-seasonal distribution of microplastics in the surface water of River Benue, North Central Nigeria

Rivers are critical pathways for microplastic (MP) pollution, yet data remain limited on MP presence in Nigeria's freshwater systems. This study presents the first comprehensive assessment of MP occurrence and associated risks in the River Benue, one of Nigeria's most important rivers. Surface water samples were collected in September 2023 (rainy season) and January 2024 (dry season), pre-treated with NaCl and H₂O₂ for density separation and wet peroxide oxidation, and analysed using FTIR spectroscopy and SEM-EDS. MP abundance was higher along the southern bank, ranging from 0 to 11 items L-1 in the dry season and 0 to 9 items L-1 in the rainy season. The lower rainy-season concentrations were attributed to improved hydraulic conditions, which enhanced dilution and downstream transport. Particle sizes ranged from 0.5 to 5 mm, with the 1.5-3 mm fraction being most abundant, raising concerns due to their bioavailability. Risk assessment revealed contamination factors of 2-22 and pollution load indices of 2-4.69, indicating sites with moderate to elevated risks. The PLIzone (3.23) confirmed severe pollution across the river, potentially warranting remediation. MP distribution patterns are strongly associated with anthropogenic activities, including commerce, transportation, and waste disposal. This study provides crucial baseline data on MP pollution in River Benue and supports the development of targeted management strategies. For a more comprehensive understanding, future investigations should explore the collection of larger sample volumes and asses contamination in the sediments and biota. These findings contribute to global efforts in understanding freshwater MP pollution, particularly in understudied tropical river systems.

GIS-based integration of marine data for assessment and management of a highly anthropized coastal area

Monitoring coastal marine environments by evaluating and comparing their chemical, physical, biological, and anthropogenic components is essential for ecological assessment and socio-economic development. In this study, we conducted an integrated multivariate analysis to assess the descriptors of the Marine Strategy Framework Directive at a regional scale in the Tyrrhenian Sea (Italy), with a specific focus on the densely populated coastal zone of the Campania region. Physical, chemical, and biological data were collected and analyzed in 22 sampling sites during three oceanographic surveys in the Gulf of Gaeta (GoG), Naples (GoN), and Salerno (GoS) in autumn 2020. Our results indicated that these three gulfs were distinct overall, with GoN being more divergent and heterogeneous than GoG and GoS. The marine area studied in the GoN had more favorable hydrographic and trophic conditions and food web characteristics, except for the mesozooplankton biomass, and was closer to socio-economic factors compared to the GoS and GoG. Our analysis helped us find the key ecological features that define different sub-regions and connect them to social and economic factors, including human activities. We highlighted the relevance of primary and secondary variables in terms of the comprehensive ecological assessment of a marine area and its impact on specific socio-economic activities. These findings support the need to describe and integrate multiple descriptors at the spatial scale.

Microplastic occurrence, distribution, and zonation at Paraná's beaches-South of Brazil

Microplastics are emerging pollutants that are increasingly reported on beaches and potentially impacting the environment and ecosystems. This study presents the first assessment of microplastic (MP) abundance and distribution on oceanic beaches of Paraná, South Brazil. Surface sediments samples retrieved from different beach zones across four beaches were analyzed for their MP (in the 1 to 5 mm size fraction-large microplastics) abundance, morphotype, and polymer composition. MP were found on all the studied beaches, totaling 846 particles, with mean concentrations of 51.9 MP/m2 or 2.3 MP/kg dw. The most common morphotypes were fragments (40%), styrofoam (28%), and foams (10%), mainly composed of polyethylene (35%) and polypropylene (29%). MP concentration distribution significantly differed between beach zones, and morphotype distribution showed differences between beaches. MP distribution followed a cross-shore pattern, with the backshore as a main accumulation area. Our study suggests that natural environmental factors such as grain size and beach slope primarily control MP distribution and accumulation along sandy shores. At the same time, the proximity of potential MP sources influences morphotype variation among beaches.

Microplastics and the freshwater plankton: Effects on grazing and mortality

When studying the effects of microplastics (MP) on zooplankton in freshwater environments, there is a knowledge gap at the community level, as most studies use monocultures under laboratory conditions with limited comparability to field studies. The aim of our study was to investigate the uptake of MP at environmentally relevant concentrations by a natural zooplankton community feeding on native phytoplankton. Rotifers and cladocerans comprised more than 96 % of total zooplankton community, while nauplii and copepodites dominated the copepod community. To test the possible change in phytoplankton grazing and zooplankton mortality after MP exposure, zooplankton were exposed to three different polyethylene MP sizes: A (1-5 µm), B (27-32 µm), and C (45-53 µm) during 96 hours. Ingestion in group A was observed in 34 % of rotifers, 20 % of cladocerans and 67 % of copepods. In group B, only cladocerans ingested MP, and to a much lower extent (2 %), which could be due to the composition of the community. None of the zooplankton studied ingested MP particles in group C. The ingestion of MP decreased phytoplankton consumption, and phytoplankton abundance varied greatly between samples. The highest phytoplankton abundance was observed in the A samples with the highest proportion of ingested MP, indicating a significant reduction in grazing pressure that allowed phytoplankton to proliferate. This result, combined with the highest mortality of cladocerans in the A samples (12.7 ± 0.91 %), indicates the negative impact of MP on the normal functioning of the freshwater plankton food web.

Fingerprinting risk from recycled plastic products using physical and chemical properties

The increasing production and use of recycled plastics have raised significant concerns regarding the risks associated with hazardous chemicals. The recycled plastics can accumulate potentially hazardous chemicals, many of which are unknown and unregulated. This study compared the physical and chemical characteristics of recycled plastic products intended for food, oral, or skin contact applications with similar virgin plastic products. The results revealed significant changes in the surface morphology and elevated concentration of organic and inorganic chemicals in the recycled plastics compared to the virgin plastics. Specifically, metal(loids) concentrations were over 10 times higher, PFAS levels were twice as high, and PAH levels were three times higher in the recycled plastics. The calculated Hazard Index (HI) indicates up to a twofold increase in recycled plastics for both adults and children compared to virgin plastics, specifically through microplastic ingestion. The HI values exceed 1 for recycled plastic ingestion, therefore it falls in high-risk category due to the associated chemical exposure from microplastics.

Short-term oral exposure to nanoplastics does not significantly impact the antiviral immune response of the mouse

The increasing prevalence of nanoplastics (NPs) in the environment, particularly polystyrene (PS) nanoparticles, raises concerns regarding their potential impact on human and animal health. Given their small size, NPs can cross biological barriers and accumulate in organs, including those critical for immune functions. This study investigates the effects of short-term oral exposure to 100 and 500 nm PS NPs on the adaptive immune responses during viral infections in vivo, using vesicular stomatitis virus (VSV) and lymphocytic choriomeningitis virus (LCMV) as models. Male and female C57BL/6 mice were orally exposed to PS NP for a period of 28 days, during which they were infected with either VSV or LCMV to study the humoral and cellular responses, respectively. The humoral responses were assessed by measuring total and VSV-specific antibody levels, and splenic immune populations. T cell phenotypes, activation, exhaustion and functionality towards LCMV epitopes were studied as readouts of the cellular responses. Our results demonstrate that short-term NP exposure does not significantly affect the generation or neutralizing capacity of antibodies against VSV, nor the cellular responses directed against LCMV. These findings indicate that, under these conditions, PS NP exposure does not significantly compromise the adaptive immune responses during viral infections, underscoring the value of in vivo models.

Interface adsorption characteristics of microplastics on multiple morphological arsenic compounds

Polystyrene (PS) and polyethylene terephthalate (PET) are commonly used materials that degrade into microplastics in the environment. These microplastics, possessing unique physical properties, can adsorb pollutants and contribute to composite pollution effects. This study examined the loading characteristics and toxic effects of PS and PET on six arsenic compounds, revealing that PS and PET displayed different adsorption capacities for these compounds, with PS demonstrating high adsorption for monomethylarsonic acid (MMA). The adsorption kinetics and isotherm analyses indicated that arsenic compounds quickly reached equilibrium on PS and PET. The kinetics were effectively described by pseudo-first-order models, and the isotherms aligned with the Langmuir and Freundlich models. Furthermore, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were used to desorb arsenic compounds bound to PS and PET. The effects of aging, pH, salinity, anions, and humic acid (HA) on the ability of inorganic arsenic (iAs) to bind to PS and PET were analyzed. The results indicated that aging and HA increased the adsorption capacity of the microplastics, while salinity, anions, and elevated pH negatively affected this capacity. Additionally, the influence of microplastics and iAs on the clearance of free radicals by reduced glutathione (GSH) was explored. Microplastics inhibited the clearance of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) by GSH, whereas iAs, especially arsenate, facilitated this process, likely due to synergistic effects with the oxidized form of GSH generated through GSH reactions. This study offers a theoretical foundation for understanding how microplastics transport various forms of arsenic compounds and their potential environmental risks.

Ocean current modulation of the spatial distribution of microplastics in the surface sediments of the Beibu Gulf, China

Microplastic pollution, a major global environmental issue, is gaining heightened attention worldwide. Marginal seas are particularly susceptible to microplastic contamination, yet data on microplastics in marine sediments remain scarce, especially in the Beibu Gulf. This study presents a large-scale investigation of microplastics in the surface sediments of the Beibu Gulf to deciphering their distribution, sources and risk to marginal seas ecosystems. The results reveal widespread microplastic contamination, with an average abundance of 391 ± 27 items/kg in sediments. The spatial variability of microplastic abundance was significant, with lower levels in the western Beibu Gulf and higher concentrations in the northeastern and southeastern regions. The spatial distribution of microplastics was largely driven by geological features, hydrodynamic conditions, and human activity, with minimal influence from local environmental factors such as water depth, sediment grain size, organic carbon content, and sediment types. The pollution load index (PLI) suggests a low level of microplastic contamination, but the polymer hazard index (PHI) identified a high ecological risk, likely due to the presence of PVC, a polymer with higher chemical toxicity. Our findings highlight the significant role of hydrodynamic processes in determining microplastic distribution in the Beibu Gulf. These insights enhance our understanding of microplastic dispersal and its governing factors in semi-enclosed marginal seas, providing foundation for targeted pollution control strategies.

Examining magnetic susceptibility as a proxy for microplastic pollution in granulometric fractions of road dust: A case study in Warsaw, Poland

The main objective was to assess the contamination of road dust (RD) with microplastics (MPs) and plasticizers and to investigate whether magnetic susceptibility (χ) can indicate MP pollution. The study employed laser direct infrared (LDIR) imaging with a quantum cascade laser (QCL), magnetic susceptibility measurement using the MFK1-FA Kappabridge, and gas chromatography-mass spectrometry (GC-MS). RD collected in Warsaw was divided into the fractions: 0.8 mm (1-0.8 mm), 0.6 mm (0.8-0.6 mm), 0.4 mm (0.6-0.4 mm), 0.2 mm (0.4-0.2 mm), and <0.2 mm. MP analysis revealed materials such as polypropylene and rubber, with the highest number of MPs (51,660 particles) in the <0.2 mm. RD was analyzed for bisphenol A and phthalic acid esters, with the highest concentrations of DEHP and DBP in the <0.2 mm fraction. χ were highest in the fraction <0.2. Strong correlations were found between χ and DEHP (0.78), DBP (0.96), and BPA (0.89) for WAW2 and between χ and MPs (0.97) for WAW4. Strong correlations were also observed for the 0.2 mm and <0.2 mm fractions between χ and DBP. The main conclusion is that χ strongly correlates with DEHP and DBP in the <0.2 mm fraction and with MPs in the 0.2 mm fraction. This study is novel due to the limited research on using χ as a screening method for MP pollution, making it a promising, cost-effective tool for pollution monitoring. The results could support the development of simplified monitoring tools, helping to assess human exposure risks and improve environmental management strategies.

Automotive Application of Chemically Foamed rPET

This study investigated the automotive applicability of parts produced from a newly developed foamed recycled polyethylene terephthalate (rPET). The injection molded part contained a combination of both endothermic and exothermic foaming agents and phosphorus (Exolit OP 1240) (OP)- and melamine polyphosphate (MPP)-based flame retardant agents. The parts were produced using a breathing mold technique to achieve a suitable level of foaming. The aim was to produce lighter parts made of recycled material that also complied with the fire safety automotive industry standards. Computer tomographic scans revealed the foam structure formed successfully, which contributed to an improved strength-to-weight ratio. The scans further showcased that larger cells tended to form in the thicker areas within the part, while smaller cells generally formed in the thinner areas. Finite element simulations showed that the large cell formation in the thicker parts had no effect on the part's load bearing property, and there were not stress concentration points after the boundary conditions were defined. The sample produced from the material was determined to be a possible replacement of small-sized automotive components.

The role of marine microalgae in the transmission of HOCs from contaminated microplastics in the aqueous environment

The prevalence of microplastics in marine environments is recognized for its ecotoxicological risks as vectors for hydrophobic organic contaminants (HOCs). This study explored the role of microalgae as vectors in the transfer of Phenanthrene (Phe) from contaminated microplastics to marine filter feeders. Employing a spatial exposure system, the sorption of Phe onto polyethylene (PE) particles, its desorption mediated by microalgae into microalgal suspensions, and subsequent accumulation in the tissues of filter feeders were investigated. In the spatial exposure system for clams, after 28 days of exposure, Phe concentrations in clams' tissues were 67.71 ng/g and 84.21 ng/g for the medium with and without microalgae, respectively; however, no statistically significant difference was observed between them (p > 0.05). In the spatial exposure system for mussels, the highest Phe concentrations in mussels' tissues were 277.71 ± 25.98 μg/g in the digestive glands after 3 days of exposure and 185.32 ± 35.76 μg/g in the mantle after 6 days of exposure, both in the Tetraselmis helgolandica suspension. Significant differences were observed between the control group and the T. helgolandica suspension group from 3 to 10 days of exposure (p < 0.05). Although microalgae were confirmed to enhance the desorption of Phe from PE particles, their role in significantly increasing the bioaccumulation of Phe in filter feeders was less than anticipated, showing no significant long-term differences between experimental groups with and without microalgae. The potential biodegradation of Phe by marine organisms was also observed, which may have contributed to the overall transfer and bioaccumulation processes, introducing an additional layer of complexity to the interpretation of the results. These findings suggest that microalgae can act as intermediate carriers facilitating the transfer of Phe, albeit with the impact of various influencing factors not aligning with initial hypotheses. The study highlights the need for further investigation into how different microalgal species and environmental conditions affect the fate of HOCs absorbed by microplastics, contributing to an enriched understanding of microplastic impacts in marine ecosystems. This establishes that microalgae mediate the transfer of Phe from microplastics into benthic filter feeders, affirming their role as significant vectors in contaminant dynamics.

Towards quality-assured measurements of microplastics in soil using fluorescence microscopy

Fluorescence microscopy is increasingly seen as a fast, user-friendly, and high-throughput method for detecting microplastics (MPs) in soil; however, its effectiveness across diverse MP types and soil properties remains underexplored. This study tested a fluorescence microscopy-Nile red (NR) staining approach on eight MP types, covering both biodegradable and non-biodegradable plastics, in three size ranges (≤ 150 µm, 100-250 µm, 500-1000 µm) across loamy, clayey, and sandy soils. Each sample, processed in triplicate, underwent a relatively quick and straightforward extraction procedure involving density separation, organic digestion, and NR staining, followed by fluorescence and bright-field microscopy. A new digital image analysis pipeline using Image J was developed to expedite and (semi)automate MP quantification. Recoveries ranged from 80% to 90% for MPs with a Feret diameter of 500-1000 µm, regardless of soil type. In contrast, the recovery of smaller MPs (Feret dia. ≤ 250 µm) varied depending on the soils and plastic types: recoveries for low-density polyethylene (LDPE) reached 85% in sandy soil and 90% in loamy soil, whereas those for biodegradable polybutylene adipate terephthalate/polylactic acid (PBAT/PLA) were only 60% and 10%, respectively. The lowest recovery rate was observed in clayey soil and for biodegradable plastics. The method was tested on non-agricultural soil samples, yielding a MP mean number concentration of 20.7 ± 9.0 MPs/g for MPs sized from dia. ≥ 25 µm, comparable to Fourier transform infrared (FPA-µ-FTIR) results of 13.1 ± 7.3 MPs/g (p > 0.05). We conclude that fluorescence microscopy with NR staining and automated particle quantification offers a time-efficient, reproducible, and accurate method for MP detection in light-textured soils, whereas limitations remain for reliable MP analysis in clay-dominated soils.

Integration of microplastics and heavy metals in the potential ecological risk index: Spatial pollution assessment of sediments in the inner Gulf of Thailand

Microplastics (MPs) are emerging coastal pollutants that finally accumulate in surface sediment. The ecological risk of MPs has been individually assessed although the other pollutants also be contaminated and may cause the risk to the ecosystem. In addition to contamination from other pollutants, the ecological risk of the considered area should include the risk factor from MPs. This study examines the spatial distribution of MPs and heavy metals (HMs) in surface sediments within the inner Gulf of Thailand and evaluates their coordinated potential ecological risk. Microplastics were identified using microscopic FTIR, with an average abundance of 1381.97 ± 2254.33 pieces/kg, peaking in the Tha Chin River. MP types included polypropylene (PP), polyethylene (PE), and various others, primarily in the 16-100 μm size range. Principal component analysis revealed distinct spatial distribution patterns for MPs based on type and size. The vertical distribution in sediment showed that MP abundance decreased with increasing depth from the surface. Heavy metal contamination showed higher concentrations in river estuaries, with As, Cr, Cu, and Zn frequently exceeding standard guidelines. Significant positive correlations were found between most MP types and HMs, suggesting synergistic contamination from anthropogenic sources. The ecological risk factor for MPs (ErMPs = 0.33-70.22) was integrated into the potential ecological risk index (RI). The combined pollution index for MPs and HMs indicated low pollution loading (PLIsite = 0.25-1.68, PLIarea = 0.67) and low to moderate ecological risk (RI = 34.09-134.32). This study revealed the distribution of type-size-MPs and presented the first realized risk-scale approach for comprehensive risk assessment.

Transport mechanisms of particulate emissions from artificial marine structures - A review

A vast number of artificial marine structures are currently installed offshore, and the rate of new installation is increasing. Especially offshore wind farms, a sub-type of artificial marine structures, are expected to grow significantly due to ambitious installation targets from international decision-makers. With increasing numbers of installed artificial marine structures, an assessment of possible adverse effects is more important than ever. To improve the environmental friendliness of artificial marine structures, an in-depth assessment of the transport and environmental fate of particle emissions is needed. The present work provides an overview of the involved processes of particle transport in the marine environment using the example of an offshore wind turbine. In this work, a first estimation on emission quantities is given for particulate emissions from marine structures, from which it is evident that emissions will increase in the next years due to an increasing number of marine structures.

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.

Eco-friendly or eco-threat? Influence of feeding zone on biodegradable microplastic uptake in freshwater fish and its impact on environment and food safety

Biodegradable plastics (BPs) are considered a sustainable alternative to reduce the long-term plastic pollution. However, recent research indicates that the degradation time of BPs varies depending on several factors, and biodegradable microplastics (BMPs) exhibit toxicological effects comparable to those of conventional microplastics, raising concerns about their use. There is a significant lack of research on the factors affecting BMP uptake in fish, with some studies focusing on the effects of BMPs under controlled laboratory settings. This study, the first of its kind in India, aims to examine the uptake of BMPs in freshwater fish from different feeding zones-pelagic, benthopelagic, and demersal-of the Periyar River in Kerala, India. Xenentodon cancila (pelagic; n = 80), Etroplus suratensis (benthopelagic; n = 80) and Anabas testudineus (demersal; n = 80) were selected for the study. The gastrointestinal tract (GIT) and edible tissues were isolated and analysed. BMPs were observed in the following order: benthopelagic > demersal> pelagic. Highest mean BMP abundance was recorded in E. suratensis (benthopelagic) i.e. 0.24±0.05 items/individual (0.04±0.01 items/g) in GIT and 0.08±0.03 items/individual (0.002± 0.00 items/g) in edible tissues. Poly (butylene adipate-co-terephthalate) (PBAT) was the only polymer observed. Adults have a comparatively higher risk of BMP exposure from E. suratensis and A. testudineus than children and aged individuals. The presence of BMPs in freshwater fish collected from the three feeding zones indicates widespread contamination across diverse habitats. This finding suggests that BMPs, despite their biodegradable nature, persist in aquatic environments long enough to enter the food web and is a growing environmental concern that must be addressed and appropriate strategies should be made to align with the goals of reducing pollution and protecting ecosystems.

Characterization of microplastics in sediments and surface waters of Turkish lakes

This study examined microplastic (MP) pollution in the sediments and surface waters of seven distinct lakes in Turkey, aiming to assess the status and characteristics of MP contamination. Hydrogen peroxide was introduced to eliminate organic matter present in the samples. MPs were separated and filtered using methods based on differences in density using ZnCl2 (d: 1.65 g cm-3) solution. Microplastics were subjected to Nile red staining observed using a fluorescent microscope, and subsequently, the types of polymers were identified through ATR-FTIR analysis. MP concentrations varied among lakes (p < 0.05), with Borçka Dam Lake (0.69 ± 0.65 MP L-1) exhibiting the highest levels in water, while Karagöl (Şavşat) Lake (344 ± 188 MP kg-1) showed the highest sediment contamination. Five distinct types of polymers were identified, with polyethylene and fragments being predominant in water, while polypropylene and fibers were more prevalent in sediment. The fibers predominantly measured less than 500 μm in length, whereas the fragments exhibited a more uniform distribution. The results indicate that microplastic pollution is prevalent in lake ecosystems, with human activities such as tourism, fishing, and urban waste discharge which have been identified as significant contributors. This study underscores the pervasive presence of microplastic pollution in protected areas and stresses the necessity for robust mitigation strategies to tackle the impacts of tourism on freshwater ecosystems. Additional investigations will elaborate on the precise origins, transport mechanisms, and ecological consequences of MPs, facilitating the formulation of efficient response strategies.

Plastics and their derivatives are impacting animal ecophysiology: A review

Nowadays, plastic pollution is one of the most significant issues affecting the environment, posing a serious threat to marine biodiversity, ecosystem stability, and human health. Millions of tons of plastic waste enter the oceans every year, and the impact of microplastics (MPs) is much more worrying than visible contamination. The presence of these particles puts a strain on ecological dynamics, causing a significant impact on the health of marine organisms and affects humans due to the interconnection existing with the environment and the food chain. This review article examines the different ways in which MPs interact with marine life, the mechanisms that drive this pollution, and the cascading consequences for the health of organisms and ecosystems. It also highlights the critical links between plastic pollution and human health and underlines the urgency of a global and coordinated approach to address this growing crisis. Only through deeper understanding, increased awareness and collective action can we hope to mitigate the significant impacts of plastic pollution and ensure a sustainable future for oceans and our planet.

Evaluation of phenotypic and behavioral toxicity of micro- and nano-plastic polystyrene particles in larval zebrafish (Danio rerio)

Plastic particles have been found in all environments and it is necessary to understand the risks these particles pose in, and to, the environment. The objectives of this work were to understand the toxic effects of varying size and concentration of polystyrene (PS) micro- and nano-plastics in zebrafish embryos and their fate within the larvae. In this work, larval zebrafish (Danio rerio) were exposed to six sizes (0.05, 0.25, 0.53, 2.1, 6.02, and 10.2 µm diameter) and concentrations (0.0005 to 0.2 µg/µL) of PS micro/nanoplastics particles. The zebrafish embryo toxicity (ZET) and the general and behavioral toxicity (GBT) assays were used to determine particle toxicity in embryos. Behavioral analysis was performed and micro/nanoplastics uptake and organ distribution were assessed. Phenotypic and behavioral toxicity was observed in all exposures with the exception of 0.25 µm particle-exposed larvae. Significant phenotypic toxicity was seen at the highest tested exposure concentration, with some sizes showing potential recovery as time increased in the assay. Behavioral analysis demonstrated a decrease in baseline activity across all micro- and nano-plastic sizes. Significant increases in light-dark responses were recorded in ZET assays of smaller-sized particles and no significant effects were observed at larger sizes. Significant decreases in this response were reported in the GBT assays of all tested sizes with the exception of the 0.05-µm particles. These assays demonstrate the general, developmental, and neurotoxicity of micro/nanoplastics to a model organism, which can be used to infer individual and population-level effects of exposure.

Seasonality, wind and characteristics of plastic polymer accumulation on Western Australia's south coast

Global studies have investigated plastic polymer distribution, but few have investigated the drivers of polymer deposition. Little work has been done in Australia, particularly on Western Australian beaches. In 2018, Wow Ecotours collected daily plastic samples from Shelley Beach on the south coast of Western Australia. A subset of 873 items was taken from five different density categories, and their polymer types were identified using Raman Spectrometry. The most abundant polymer was high-density polyethylene 45 %, followed by polypropylene and low-density polyethylene, with 33.5 % and 14 %, respectively. Onshore wind was the predominant factor driving plastic accumulation on the beach, but this did not vary significantly between polymers. The spring season has significant fluctuations in the length, mass, and area of the collected samples.