Microplastics in the marine environment

Prooxidant-based polyolefins exhibiting no evidence of biodegradation under marine environments

The use of oxo-biodegradable plastics has become increasingly controversial due to insufficient evidence supporting their environmental benefits. In particular, their biodegradability in marine environments remains poorly understood, sparking a global concern that the rapid abiotic fragmentation of these plastics could harm marine ecosystems. Here, we assessed the marine biodegradability of polyethylene and polypropylene films containing a commercial oxo-biodegradable prooxidant and compared them to their untreated counterparts using biochemical oxygen demand tests. Our findings revealed that while the prooxidant enhanced oxidative degradation and fragmentation of the polymers, it did not improve their marine biodegradability. Neither the initial nor the UV-exposed samples, with or without the prooxidant, exhibited significant marine biodegradability. The accelerated oxidative breakdown of these so-called oxo-biodegradable polyolefins, coupled with their limited marine biodegradability, may worsen the ocean microplastic pollution. Therefore, the potential environmental risks of using prooxidants should be carefully considered to prevent unintended negative impacts on the environment.

Plastic litter is rapidly bioeroded in mangrove forests

Due to their architectural and hydrodynamic properties, mangrove forests are emerging as global hotspots for plastic sequestration. Mangroves encroached by coastal cities contain up to two orders of magnitude more plastic than their non-urban counterparts. In urban mangroves, plastic substrata are often used as microhabitats, but the consequences of this interaction for the degradation process of plastics in the environment are unknown. Hence, we hypothesized that plastics are differentially colonized and transformed by distinct macrobenthic assemblages in urban vs. wild mangrove forests. To test this hypothesis, plastic sheets (low-density polyethylene, LDPE; polypropylene, PP; polyethylene terephthalate, PET and expanded polystyrene, EPS) were placed in two positions (on-ground and above ground), and the colonizing biota assessed after four months in urban and wild mangrove forests in the southern Colombian Caribbean. We found 19 plant and animal taxa scraping, burrowing into, biting, fracturing, etching, and boring through plastic sheets, demonstrating that bioerosion is a critical degradation pathway that influence the fate of plastic litter in the environment. As hypothesized, there were significant differences in the structure of macrobenthic biota and functional groups of bioeroders between urban and wild forests. Moreover, the bioerosion rate of EPS and PP was faster in urban than in wild mangrove forests. These findings challenge the view that the biological transformation of plastics is a slow process, mainly driven by microorganisms.

Reefs of Brachidontes exustus and Petaloconchus spp. as traps and sink for microplastics in tropical coastal areas

Microplastics (MPs) are emerging contaminants in marine environments. This study quantified, chemically identified, and described MPs in reefs of Brachidontes exustus and Petaloconchus spp. on the tropical coast of Brazil. Samples were collected in reefs of northeastern Brazil in the dry (February) and rainy (July) seasons of 2023. MPs were classified (shape and color), measured, and counted. MPs were present in all samples. Most MPs were transparent fibers, with more particles in Brachidontes reefs and during the rainy season. MPs were mainly polystyrene, polypropylene, polyester, and polyamide. The characteristics of reefs and seasonal changes in rainfall are the main drivers of the accumulation of MPs, and the shape and chemical composition of particles reveal that their principal source is probably the textile and apparel industry. The trapping of MPs in Petaloconhus spp. and Brachidontes exustus reefs reveals that biogenic reefs may be a sink for microplastics in tropical coastal areas.

Microplastic distribution and its implications for human health through marine environments

Microplastics are pervasive pollutants in the ocean, threatening ecosystems and human health through bioaccumulation and toxicological effects. This review synthesizes recent findings on microplastic distribution, trophic transfer, and human health impacts. Key findings indicate that microplastic abundance is highest in the Indian and Pacific Oceans, particularly in seawater and sediment. Morphologically, fibers and fragments dominate, with polypropylene, polyethylene, and polyester being the most prevalent polymers. Smaller particles (<1 mm) undergo long-range transport via ocean currents, while biofouling accelerates vertical sinking. Trophic transfer studies confirm microplastic ingestion across marine food webs. Human exposure is associated with seafood consumption, inhalation of airborne particles, and potential dermal contact, particularly in marine environments. These exposures can lead to adverse health effects, including inflammation, organ damage, respiratory issues, oxidative stress, and metabolic disruptions. Finally, this review explores potential strategies for minimizing human exposure to microplastic pollution in marine environments, paving the way for further research in this critical area.

First Evidence of Microplastics Burden in Surface Waters of Budhabalanga Estuary, Chandipur, Eastern India: Potential Threat to Aquatic Ecosystem

Microplastic pollution has emerged as a new global concern because of its ubiquitous and persistent nature. Due to the rising use of plastics and discharge of plastic waste into coastal water bodies from point and non-point sources, the occurrence of microplastics along coastal ecosystems has become very prevalent. The current study is the first of its kind to evaluate the presence of microplastics in the surface water of river estuary along the coast of Odisha. Six GPS-fixed locations were used to collect the surface water samples from the Budhabalanga river estuary in Chandipur, Odisha, India. The samples were then subjected to further investigation to determine the types of microplastics present. The average microplastic abundance, according to our findings, ranged from 9.33 ± 2.11 items L-1 to 28.50 ± 2.77 items L-1. Microplastics come in a variety of colours and shapes, but the most prevalent kind is fibre-shaped and black in colour. The pollution load index of the sampling area was calculated to be 4.25 which is categorized under ecological risk level I. FE-SEM images clearly showed the topology of microplastics and ATR-FTIR analysis confirmed the presence of polyethylene, polypropylene, polyvinyl chloride (PVC), nylon, polycarbonate (PC), ethylene vinyl acetate (EVA) and polystyrene (PS) at sampling stations. Our investigation provides useful information that helps to reduce the ecological risk in habitats connected with contaminated sites, including both aquatic and terrestrial habitats.

From mudflats and saltpans to Open Sea: Plastic ingestion and PBDE/MeO-BDE accumulation in Waterbirds from southern Portugal

Plastic ingestion greatly affects waterbirds, causing lacerations and potentially leading to health disruptions from chemical leaching. Polybrominated diphenyl ethers (PBDEs), used as flame retardants in plastics, remain persistent in the environment despite restrictions, along with the less studied methoxylated PBDEs (MeO-BDEs), that may result from their transformation. Since most plastic pollution in the heavily impacted marine environment comes from terrestrial sources, freshwater/estuarine and coastal environments can also be heavily exposed to contamination. Nonetheless, research in these areas remains limited. We studied the breeding waterbird community from Ria Formosa (Algarve, Portugal) as a proxy of such contamination and sampled the wader species feeding in mudflats and saltpans, little terns feeding in lagoon channels and the adjacent sea, opportunistic gulls feeding mostly on fishery discards and landfills and marine foraging gulls feeding exclusively at sea. Specifically, we assessed 1) plastic ingestion, through the analysis of regurgitations and faeces, and 2) PBDEs and MeO-BDES uptake in eggs, feathers, and preen oil. Results showed that, overall, microplastics were the most commonly detected particles. Yellow-legged gulls (Larus michahellis) and little terns (Sternula albifrons) ingested more particles, especially fibres. Eggs of black-winged stilt (Himantopus himantopus) and yellow-legged gull had higher PBDEs concentrations, while MeO-BDEs did not differ among species. Feathers exhibited low detection values, but MeO-BDEs suggests marine invertebrates' consumption. Little terns accumulated more PBDEs and MeO-BDEs, suggesting an association between plastic ingestion and contamination load. However, species-specific traits, dietary preferences, and foraging areas should also be taken into consideration.

Microplastics in spotted seal stomachs from the Bering and Chukchi seas in 2012 and 2020

Microplastics are found throughout marine environments, including the Pacific Arctic. Given their ubiquity, it is important to understand how microplastics biomagnify through food webs and accumulate in upper trophic level organisms, such as marine mammals. Spotted seals (Phoca largha) occur throughout the Bering, Chukchi, and Beaufort seas of the Pacific Arctic and are harvested for subsistence by many Alaska Native communities. We examined stomachs of subsistence-harvested spotted seals for microplastic presence and compared between age class (pups <1 yr and non-pups ≥1 yr), harvest location (Gambell and Shishmaref, Alaska, USA), and harvest year (2012 and 2020). We processed stomachs using enzymatic digestion and vacuum filtration, enabling microplastic detection while preserving prey hard parts (e.g., fish otoliths) for diet analysis. Filters were inspected and microplastic concentration was calculated for each stomach. We examined 34 (16 from 2012 and 18 from 2020) stomachs from Gambell and Shishmaref, and 33 (97.1 %) stomachs contained 1 to 23 particles for a total of 190 microplastics. No significant difference in microplastic concentration was found between age class, harvest location, or year. This baseline study showed that similar levels of microplastics have been ingested by spotted seals for at least a decade. Furthermore, we found more microplastics in spotted seal stomachs that had either benthic prey or higher trophic prey (i.e., fish). Further study of microplastic ingestion is needed to assess health impacts to spotted seals, other ice-associated pinnipeds, and subsistence users that serve as indicators of ecosystem health in the Bering and Chukchi seas.

Overview of monitoring methods and environmental distribution: Microplastics in the Indian Ocean

Microplastics are ubiquitous globally, posing a significant threat to human health. Notably, the Indian Ocean ranks second in microplastic contamination, emerging as a major source of pollution. In response to this risk, neighboring countries are actively addressing severe plastic pollution and deficiencies in waste management. Research on microplastics in Indian Ocean seawater commenced in 2016. This paper reviews the research status and trends, detailing sampling, extraction, and identification methods. We categorize 43 studies by trawl sampling and other techniques, summarizing microplastic abundance, size, shape, color, and polymer types. Microplastic distribution varies widely in the Indian Ocean, peaking in the East, West, and along the Indian coast. Fiber and debris microplastics are the most, the main colors are black, blue, white and transparent, and the polymer types are mainly PE, PP and PS. Oceanic convergence intensity affects microplastic distribution globally, intensifying accumulation. This study highlights the need for standardized microplastic sampling and analysis in Indian Ocean countries. Collaborative surveys and investigations are crucial to addressing pollution.

Temporal dynamics of communities on plastic debris in a polluted marine habitat

This study investigated the succession of prokaryotic and eukaryotic communities on polystyrene panels deployed for 25 weeks in a harbour environment influenced by anthropogenic activities. These activities resulted in an excess of nutrients from sewage and agricultural discharges, as well as the release of hydrocarbons and other pollutants. An eDNA metabarcoding approach targeting the 16S and 18S rRNA genes was used. This innovative methodology allowed a detailed analysis of the community development and succession, providing an in-depth view of biodiversity and ecological dynamics associated with plastic substrates. The microbial biofilm community remained stable throughout the experiment enriched in Rhodobacteraceae (16.97 %) and Flavobacteriaceae (17.99 %). Only minor differences observed between the early and late stages, consistent with their identification as key components of the biofilm. For the eukaryotic community, the early colonization stages were dominated by Alveolata (63.39 %) and Stramenopiles (23.53 %). Later stages showed changes in the community with Chlorophyta (20.14 %) and Opisthokonta (94.32 %) being the most abundant phyla. Richness, as alpha diversity index based on retrieved ASVs, varied from 1875 to 2481 and from 159 to 405 for prokaryotes and eukaryotes, respectively. This indicated an adaptive succession of plastic-associated communities in aquatic ecosystems. Potential plastic-degrading groups found in the prokaryotic community showed a dynamic distribution across colonization stages. Trophic dynamics on plastic debris showed that heterotrophs dominated the eukaryotic community. Our results confirmed the role of plastics as vectors in marine ecosystems, for complex communities composed of bacteria, algae, and invertebrates. This highlighted potential risks to the health of marine ecosystems.

Settling velocities of microplastics with different shapes in sediment-water mixtures

The widespread distribution of microplastics (MP) in aquatic systems highlights the need for a clear understanding of how they are transported and accumulate on the bottom of water bodies. Developing predictive models for MP dispersion, sedimentation, and bioaccumulation is crucial for informing regulatory decisions and mitigating the impact of MP and related pollutants. Among the key parameters, MP settling velocity is considered the most critical for predicting their behavior in aquatic environments. Recent studies suggest an intricate and not fully understood relationship between MP settling and sediment dynamics. To date, none of the current models can predict how sediment modifies MP settling velocity. Therefore, previous understanding on MP settling does not fully account for the sedimentation of MP in aquatic ecosystems, where sediment suspension is present. This study provides further evidence that the presence of sediment alters the sedimentation rate of MP based on their shape, offering a quantitative estimate of this interaction. For the first time, the effects sediment interaction has on MP sinking trajectories and inclinations are presented. A preliminary, modified version of an existing formula is proposed to estimate MP settling velocity in the presence of sediment, laying the groundwork for more accurate predictive models of MP transport in aquatic environments.

An Atmospheric Chemistry Perspective on Airborne Micro- and Nanoplastic Particles

Micro- and nanoplastic particles (MNPPs) are emerging pollutants with significant environmental impacts due to their persistence, increasing concentrations, and potential health risks. Most MNPP studies have focused on identifying, quantifying, and assessing their ecotoxicological impacts in water or soil. However, the atmosphere is crucial in transporting and chemically transforming MNPPs. Further, well-established aerosol particle characterization techniques are underutilized and inconsistently applied in existing atmospheric MNPP studies. This perspective synthesizes the existing literature and addresses future research needs unique to atmospheric MNPPs, highlighting the need to bridge the microplastics and atmospheric aerosol communities to better understand their sources, chemical transformations, transport mechanisms, as well as their health effects and ecological impacts, which differ from those in soil and water. Advancing research in these areas requires standardized methods and a multidisciplinary approach to comprehensively assess MNPP interactions across environmental compartments, providing essential insights into their environmental fate and risks.

Polystyrene and polyethylene perturb the structure of membrane: An experimental and computational study

There are various types and mixtures of nanoplastics (NPs) that are ubiquitous in the environment. Nevertheless, it remains a challenge to investigate the membrane effects and in vivo processes of mixtures of NPs due to their compositional complexity. In the present study, a framework combining cell assays, molecular dynamics (MD) simulations, and toxicogenomic network analysis was implemented to elucidate the differential effects of polystyrene (PS), polyethylene (PE), and the PS-PE mixture on cell membrane integrity. The cellular experiments indicated that PS, PE, and the PS-PE mixture could induce leakage of intracellular substances across the cell membrane, thereby demonstrating membrane damage. Molecular dynamics simulations revealed that these NPs could surmount energy barriers to infiltrate lipid membranes, leading to the formation of membrane pores. Notably, the PS-PE mixture showed a stronger effect than the single component. As evidenced by both cellular experiments and MD simulations, this phenomenon might be resulted from the elevated affinity of the PS-PE mixture for the lipid bilayer. The characteristic enhanced its propensity to engage with membrane structures, thereby inducing more pronounced disruption of membrane integrity. The analysis of biological networks underscored metabolic disorders and oxidative stress as key pathways for hepatotoxicity induced by NPs, elucidating the membrane damage and hepatotoxic mechanisms of NP mixtures. The study established a critical framework for assessing health risks of diverse NPs and their mixtures, while providing novel insights into the multiscale characterization of toxicity mechanisms spanning from molecular interactions to pathway-level information.

Challenges in coastal ecosystem Sustainability: Drivers of water quality degradation and their ecological impact

Coastal waters are home to a diverse range of habitats forming highly diverse transitional ecosystems such as mangroves, seagrass beds, coral reefs, and salt marshes. The health of these ecosystems is closely tied to the surrounding coastal environment, making them highly vulnerable to environmental changes that can significantly disrupt the entire coastal ecosystem. Ensuring the sustainability of these ecosystems requires a deep understanding of the factors contributing to coastal water degradation and their implications for effective ecosystem management. This review focuses on key drivers of coastal environmental deterioration such as nutrient loading, heavy metals, microplastics, toxic substances, construction activities, and their ecological consequences. These factors, whether directly or indirectly, impact aquatic organisms' physiological and biochemical processes while altering the physical characteristics of coastal landscapes, ultimately disrupting vital ecological functions. Adopting a multidisciplinary approach that brings researchers, environmental activists, stakeholders, and policymakers together is vital to start an effective dialogue for the sustainable management of coastal habitats.

Accumulation of microplastic in edible marine species from North Kerala, India

Microplastics in edible seafood constitute a significant concern, as they can accumulate in the tissues of marine organisms and entering food chain through which it reaches human and cause health risks. This study aims to investigate the presence of microplastics in the edible tissues of Marcia opima, Metapenaeus dobsoni, and Stolephorus indicus, collected from the central fish markets in Kasargod District of Kerala, India. About 9 kg of seafood (3 kg of each species) was collected from three major fish markets. From this, 50 species samples were randomly selected, totalling 150 samples representing each sample. About 193 microplastics from 150 individuals of three different seafood species were isolated and identified. Metapenaeus dobsoni was found to have the greatest number of microplastics (155) among these three species. Microplastic fibres constituted a significant part of total microplastic counts. Microplastic identification was made using a 'Leica stereo-zoom binocular microscope'; confirmation and polymer identification were made using the FTIR-ATR method. Six different polymers were identified such as polyethylene, polyethylene terephthalate, polyvinyl chloride, polyester, polytetrafluoroethylene, and polyacrylamide. Among these, microplastic analysis across all three species showed that nearly half were composed of polyethylene, with polyethylene terephthalate being the second most prevalent polymer. Additionally, Metapenaeus dobsoni has been newly reported globally as a species with microplastic contamination.

Microbiological analysis of cigarette butts and cigarette butt fibers on a tourist beach in Cartagena, Colombia

Cigarette butts (CBs) discarded on tourist beaches represent an emerging waste concern in marine-coastal ecosystems due to their persistence, low degradability, and toxicity. This study investigated CBs, cigarette butt fibers (CBFs), and beach sand in Cartagena, Colombia, as potential substrates for microbial growth. Samples were collected over five months from different beach usage zones (active, rest, and service) and analyzed for bacterial isolation, morphological and biochemical characterization, 16 S rRNA gene sequencing, and the presence of total coliforms and Escherichia coli. The results revealed the presence of both Gram-positive and Gram-negative bacteria in sand, CBs, and CBFs. Notably, Virgibacillus pantothenticus and Virgibacillus dokdonensis were identified and documented for the first time in Colombia. These findings contribute to understanding the sanitary and environmental quality of tourist beach sand and highlight potential risks to human health. Moreover, the identification of V. dokdonensis in cigarette butts discarded on beach sand is particularly relevant, as previous research suggests that certain bacterial taxa may have bioremediation potential for heavy metals.

Ingesting chitosan can promote excretion of microplastics

Recently, the presence of microplastics (MPs) in common foods such as salt and beverages has been widely reported Microplastics (MPs) have been widely reported in common foods, including salt and beverages. MPs spread through the food chain and are eventually ingested into the human body through the diet. They have been found to accumulate in human feces, blood, and liver tissues, raising concerns about the effects of continuous intake of foods containing MP on the body. We examined whether rats could rapidly excrete polyethylene MPs (average particle size of 200 μm) when the MPs and were mixed with non-digestive dietary materials in their feed (indigestible dextrin, lactosucrose, chitosan, and eggshell membrane proteins). The group that ingested chitosan showed significant changes, including increased fecal weight, increased MP excretion rate, and decreased intestinal MP retention rate. The MP excretion rates in feces 0-144 h after ingestion were 83.7% ± 3.8% in the control group and 115.6% ± 4.5% in the chitosan group. These findings indicate that chitosan effectively promotes the expulsion of polyethylene MPs. The addition of chitosan to food may reduce the potential harm caused by MPa to a variety of organisms, including humans.

Microfluidic systems in testicular in vitro culture: a powerful model tool for spermatogenesis and reprotoxicity studies

ABSTRACT

As prepubertal boys do not yet produce spermatozoa, they cannot rely on sperm cryopreservation for fertility preservation before gonadotoxic therapy, such as high-dose alkylating agents or radiotherapy in the case of childhood cancers. According to the current guidelines, cryopreservation of testicular biopsies containing spermatogonial stem cells (SSCs) may be proposed to high-risk patients for potential later therapeutic use to fulfill the patients' wish for a biological child. One promising technique for human in vitro spermatogenesis and in vitro propagation of human SSCs is microfluidic (MF) culture, in which cells or tissues are subjected to a continuous flow of medium. This provides exact control over such parameters as nutrient content and gradients, as well as the removal of waste metabolites. While MF has been shown to maintain tissues and cell populations of organs for longer than conventional in vitro culture techniques, it has not been widely used for testicular in vitro culture. MF could advance human testicular in vitro culture and is also applicable to reprotoxicity studies. This review summarizes the findings and achievements of testis-on-chip (ToC) setups to date and discusses the benefits and limitations of these for spermatogenesis in vitro and toxicity assessment.

Applicability of NMR spectroscopy to quantify microplastics across varying concentrations in polymer mixtures

Quantitative nuclear magnetic resonance (qNMR) spectroscopy could potentially be used for environmental microplastic analyses, provided the challenges posed by mixed polymer samples with varying concentrations and overlapping signals are understood. This study investigates the feasibility of qNMR as a reliable and cost-efficient method for quantifying synthetic polymers in mixtures of low and varying concentrations, addressing key challenges and limitations. Polymer mixtures were analysed using deuterated chloroform (CDCl3) and deuterated tetrahydrofuran (THF-d8) as solvents, with polystyrene (PS), polybutadiene-cis (PB), polyisoprene-cis (PI), polyvinyl chloride (PVC), polyurethane (PU), and polylactic acid (PLA) as selected polymers. Mixtures contained either low and high concentrations of each polymer or equal concentrations of all six polymers. Polymer concentrations were measured using the internal standard method. The method showed low relative errors for low concentrations of PS in CDCl3 and PVC in THF-d8, with values of -5% and 0%, respectively, while PB and PI in CDCl3 show relative errors of +5% and -3%, respectively. We observe significant linearity between nominal and measured concentrations with R 2 values ranging from 0.9655 to 0.9981, except for PU, which had high relative errors and poor linearity (R 2 = 0.9548). Moreover, simultaneous quantification of six polymers in THF-d8 proves effective at intermediate concentrations. However, overlapping proton signals are observed, causing high-concentration polymers to mask low-concentration ones. While this study demonstrates low limit of quantification (LOQ) and advances in simultaneous polymer quantification, further research is needed to improve qNMR accuracy for mixed polymer samples and environmentally relevant concentrations.

Microplastics in lakes: Distribution patterns and influencing factors

As a kind of new pollutants, microplastics (MPs) have aroused public concern due to their widespread presence and potential ecological risks. Lakes, as crucial freshwater ecosystems and important water resources, are particularly vulnerable to MPs pollution. While MPs are known to be unevenly distributed within lakes, their distribution patterns and influencing factors have not been thoroughly understood. This review analyzes 84 field studies across 64 lakes worldwide to elucidate MPs distribution patterns and their driving mechanisms. Analysis reveals that MPs abundance is typically highest near areas of intense human activity and major water inflows, though hydrodynamics and wind conditions also influence spatial patterns. MPs characteristics (shape, size, color, polymer type) show distinct distribution patterns influenced by source types, transport mechanisms, and degradation processes. While surface water MPs concentrations vary seasonally due to precipitation, wind, and human activities, sediment cores indicate increasing MPs abundance in recent deposits. Integration of water and sediment sampling reveals that MPs characteristics affect their vertical distribution, with denser particles prone to sedimentation. This review identifies key knowledge gaps, including limited data on vertical distributions and temporal variations, and emphasizes the need for standardized methods and quantitative analysis of driving factors. These reviewed findings provide a foundation for understanding MPs fate in lake ecosystems and improving risk assessment capabilities, offering valuable insights for future surveys on MPs.

Decoding the Plastic Patch: Exploring the Global Microplastic Distribution in the Surface Layers of Marine Regions with Interpretable Machine Learning

The marine environment is grappling with microplastic (MP) pollution, necessitating an understanding of its distribution patterns, influencing factors, and potential ecological risks. However, the vast area of the ocean and budgetary constraints make conducting comprehensive surveys to assess MP pollution impractical. Interpretable machine learning (ML) offers an effective solution. Herein, we used four ML algorithms based on MP data calibrated to the size range of 20-5000 μm and considered various factors to construct a robust predictive ML model of marine MP distribution. Interpretation of the ML model indicated that biogeochemical and anthropogenic factors substantially influence global marine MP pollution, while atmospheric and physical factors exert lesser effects. However, the extent of the influence of each factor may vary within specific marine regions and their underlying mechanisms may differ across regions. The predicted results indicated that the global marine MP concentrations ranged from 0.176 to 27.055 particles/m3 and that MPs in the 20-5000-μm size range did not pose a potential ecological risk. The interpretable ML framework developed in this study covered MP data preprocessing, MP distribution prediction, and interpretation of the influencing factors of MPs, providing an essential reference for marine MP pollution management and decision making.

Italian Pellets Watch: First step towards national assessment of resin pellets distribution, characterization and pollutants absorption

Resin pellets, which are highly prone to environmental dispersion, can absorb pollutants such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) once they enter marine environments. Principal aim of the study was to statistically confirm the correlation between pollutant content and the yellowing parameter - indicative of chemical aging of pellets - behind the use of pellets as a cost-effective alternative for chemical pollution assessment in the marine environment. In parallel, we first tested the use of the LIBS (Laser-Induced Breakdown Spectroscopy technique to detect the presence of metals on the surface of pellets. We conducted Italy's first national survey of resin pellets through a citizen science initiative. A total of 2270 pellets were collected from 73 beaches across 13 Italian regions and analyzed based on morphological characteristics, including discolouration, fouling presence, and porosity. From selected subsamples we extracted four PAH and six PCB congeners and examined the surface heavy metal content using LIBS technique. Pollutant concentration values were found to be correlated with the discoloration parameter of yellowing, further validating the use of resin pellets as an effective proxy for environmental pollution in place of traditional methods like mussels or others environmental matrix, as first proposed in the International Pellets Watch (IPW) framework.

Tiny pollutants, big consequences: investigating the influence of nano- and microplastics on soil properties and plant health with mitigation strategies

The impact of nanoplastics (NPs) and microplastics (MPs) on ecosystems and human health has recently emerged as a significant challenge within the United Nations Agenda 2030, drawing global attention. This paper provides a critical analysis of the influence of plastic particles on plants and soils, with the majority of data collected from recent studies, primarily over the past five years. The absorption and translocation mechanisms of NPs/MPs in plants are first described, followed by an explanation of their effects-especially particles like PE, PS, PVC, PLA, and PES, as well as those contaminated with heavy metals-on plant growth, physiology, germination, oxidative stress, and nutrient uptake. The study also links the characteristics of plastics (size, shape, concentration, type, degradability) to changes in the physical, chemical, and microbial properties of soils. Various mitigation strategies, including physical, chemical, and biological processes, are explored to understand how they address these changes. However, further research, including both laboratory and field investigations, is urgently needed to address knowledge gaps, particularly regarding the long-term effects of MPs, their underlying mechanisms, ecotoxicological impacts, and the complex interactions between MPs and soil properties. This research is crucial for advancing sustainability from various perspectives and should contribute significantly toward achieving sustainable development goals (SDGs).

Microplastic accumulation in fibrotic intestinal tissue and mesenteric adipose tissue in Crohn's disease patients

Crohn's disease (CD) patients exhibit heightened vulnerability to environmental triggers. However, the impact of microplastics (MPs) on CD remains unexplored. This study investigates MPs in ileal segments and mesenteric adipose tissue from CD patients. We recruited paired involved and adjacent uninvolved ileal segments, along with attached creeping fat (CF) and adjacent uninvolved mesenteric adipose tissue (CD-MAT) samples to assess MPs exposure of CD patients. Using laser infrared imaging spectrometer, we identified 12 types of MPs, including Chlorinated polyethylene (CPE), Acrylate copolymer (ACR), Fluororubber, and Polyethylene (PE). MP concentrations were correlated positively with the severity of intestinal fibrosis. Laser Direct Infrared spectroscopy revealed that 31.96% of MPs were 20-50 μm in size. Our findings underscored that the high-risk practices, such as frequent invasive gastrointestinal tract examinations, exacerbated of MPs accumulation in fibrotic intestines. We detected a parallel change in the concentrations of MPs at the lesion sites, with a significant increase observed compared to the surrounding tissues. When compared to CD-MAT and uninvolved ileum, the concentration ratios of PU and AUR were higher in the more fibrotic regions of CF and involved ileum, whereas CPE and Fluororubber exhibited a concurrent decrease. This suggests that MPs can penetrate the epithelial barrier and enter both fibrotic intestines and CF. This study provided the first evidence of widespread MP contamination in the fibrotic intestine and adjacent mesenteric adipose tissue of CD patients, correlating with fibrosis severity and might function as an exacerbating factor in the development of CF and fibrotic intestines.

Direct Evidence That Microplastics Are Transported to the Deep Sea by Turbidity Currents

Microplastics pervade the global seafloor, yet the mechanisms by which this pollutant is increasingly transported to the deep sea remain unclear. Fast-moving sediment avalanches (called turbidity currents) are hypothesized to efficiently transport microplastics into the deep sea. However, while this has been inferred from field sampling of the seafloor, it has never been demonstrated outside of a laboratory setting. Here, we provide direct field-scale evidence that turbidity currents in submarine canyons not only transport globally significant volumes of mineral and organic matter into the deep sea but also carry large quantities of anthropogenic particles, including microfibers and microplastic fragments. In situ hydrodynamic monitoring, coupled with direct sampling of the seafloor and material suspended by turbidity currents, reveals that even a submarine canyon whose head lies hundreds of kilometers from land acts as an efficient conduit to flush sediment and pollutants from the continental shelf to water depths greater than 3200 m. Frequent and fast turbidity currents supply oxygen and nutrients that sustain deep-sea biodiversity and fishing grounds in, and adjacent to, such canyons. Our study therefore confirms that these biodiversity hotspots are colocated with microplastic hotspots, indicating that the more than 5000 land-detached canyons worldwide can be important but previously unproven conveyors of anthropogenic pollution to the deep sea.

Harmonious assessment of mesh effect in water sieve sampling for fibrous microplastics abundance

Fibrous microplastic pollution in natural water is increasingly concerning because these particles could carry and release toxic substances, and be bioavailable of microplastics less than 100 μm, posing significant risks to ecosystems and human health. Effective monitoring and accurate data sharing are hampered by a lack of standardized sampling methods, particularly for assessing the impact of mesh size (hereafter referred to as mesh opening) on microplastics abundance. This study investigated the efficiencies of various mesh openings (50-500 μm) in water sieve sampling of fibrous microplastics using a continuous multi-layer filtration device. Surface water samples from Zhanqiao Pier, China, were processed, and the geometric properties of the collected microplastics were analyzed. The retention of fibrous microplastics was calculated using logistic models, and Monte Carlo simulations were employed to estimate the amounts of microplastics that were not retained. Data from previous studies were re-evaluated to develop a harmonious assessment protocol for estimating fibrous microplastics abundance. The results showed that larger mesh openings significantly underestimate the abundance of microplastics, missing up to 14.6 (500 μm), 8.8 (315 μm), and 2.0 (150 μm) times more fibers compared to the finest mesh opening (50 μm). Thus, coarser meshes fail to capture smaller, yet numerous, microplastics fibers. Moreover, the re-evaluated results were used to develop correction factors of the harmonious assessment and highlight the need for finer mesh openings in sampling nets and sieves to ensure more accurate data collection. Such improvements could be used to establish a globally standardized methodology for microplastics monitoring.

Increasing microplastics pollution: An emerging vector for potentially pathogenic bacteria in the environment

Microplastics (MP), plastic particles <5 mm, are of global concern due to their worldwide distribution and potential repercussions on ecosystems and human well-being. In this study, MP were collected from the urbanized Susurluk basin in Türkiye to evaluate their vector function for bacterial biofilms, both in the wet and dry seasons. Bacterial biofilms were predominantly found on polyethylene (PE), polypropylene (PP), and polystyrene (PS), which constitute the most common MP types in the region. Specific potentially pathogenic bacterial genera, including Pseudomonas sp., Comamonas sp., Salmonella spp., and Shigella spp., were prevalent on MP surfaces. Notably, PE and PP harboured numerous genera of potential human and/or animal origin such as Staphylococcus, Proteus, Escherichia, Enterococcus, and Enterobacter. Water quality played a pivotal role in bacterial biofilm formation on MP. Higher salinity in estuarine areas reduced bacterial abundance on MP, while the more polluted freshwater Nilüfer Stream harboured a higher abundance of total bacteria, particularly of potentially pathogenic strains. Seasonal variations, ambient water conditions, and polymer type are all factors that could influence bacterial colonization on MPs. This catchment-wide evaluation, which includes various habitat types (lentic and lotic systems), the enrichment of cultivable viable bacteria on microplastics (MPs) - a key factor in the spread of pathogens - has significant implications for both environmental and public health. Unlike controlled laboratory experiments or in-situ studies with various particles, this study emphasized the dynamic and complex nature of bacterial strains on MPs, which varied depending on seasonal dynamics and antropogenic impacts in open systems. Further research is needed to thoroughly investigate to fully explore the complex interactions among MPs, microbial communities, and their ecological roles, especially in the context of changing environmental factors across entire river catchments.

Microplastics in the European native oyster, Ostrea edulis, to monitoring pollution-related patterns in the Solent region (United Kingdom)

Microplastics (MPs) are the most abundant type of debris in the marine environment, creating a significant threat to aquatic ecosystems due to their persistence, ability to absorb organic pollutants and potential ingestion by marine fauna. Shellfish are particularly vulnerable to MPs accumulation as they filter large volumes of seawater, and they become an important route for human exposure to these particles. This study, the first to examine MPs in European flat oyster (Ostrea edulis) populations, aimed to quantify these particles in the gill and digestive tissues of oysters from the Solent region (southern England). Enzymatic digestion using Proteinase-K was used in this study and MPs were identified in every oyster sampled to determine whether differences in abundance, type and size of MPs exist between locations. Oysters near urban areas contained significantly more MPs than those near rural areas. Fibres were the most prevalent type of MPs, with sizes varying across locations. The study found no significant differences in MPs presence between gills and digestive tissues, and an inverse correlation between the size of MPs and oyster size. The presence of MPs in wild O. edulis could be an additional threat to the survival of an already threatened species and may pose health risks for predatory species and human consumers of seafood. The use of O. edulis as a biomonitoring species for marine MPs pollution could help determine the extent, distribution and sources of MPs, potentially informing management strategies to reduce pollution.

Technologies to eliminate microplastic from water: Current approaches and future prospects

Microplastic (MP) pollution has become a widespread environmental threat which must be addressed as it affects the water bodies, soil as well as air. MPs originally from synthetic textiles, tire abrasion, plastic waste, etc. pose the significant risks to both the environment and health due to its structure, ability to absorb toxins and act as carriers of harmful substances. This characteristic enables MPs to accumulate toxic substances and spread them within the food chain which leads to adverse effects on both the environment and human health including possible endocrine disruption. This problem needs to be solved in order to protect the self-regulatory systems of the environment and safeguard for human health. This review investigates various methods developed to eliminate MPs from water which each method exposes its own strengths and limitations. Conventional methods, such as filtration, coagulation-flocculation, and sedimentation serve as the primary line of defense but often struggle with smaller particles. Membrane filtration, magnetic separation, and electrochemical methods have shown better performance particularly for a wider MPs size range. However, their adoption is limited due to high costs and high energy requirement. A chemical approach focuses on the use of reactors to degrade MPs as a means of overcoming the problem posed by the persistent particles. Biological approaches, including bioremediation through bacteria, fungi, and algae offer eco-friendly alternatives by breaking down MPs into less harmful components. Future directions in MPs management involve the integration of these technologies for enhanced removal efficiency, the development of novel materials, and improved system designs to reduce costs and environmental impact. In summary, advancing research in biotechnological solutions and optimizing existing methods is critical to address the widespread and complex nature of MPs pollution to ensure healthier ecosystems and safer water supplies.

Designing for degradation: the importance of considering biotic and abiotic polymer degradation

Considering the increasing global plastic demand, there is a critical need to gain insight into environmental processes that govern plastic degradation in order to inform novel design of sustainable polymers. Current biological degradation testing standards focus on formation of CO2 (i.e., mineralization) alone as a diagnostic, ultimately limiting identification of structure-degradation relationships in a timely fashion. This work developed a sequential abiotic (i.e., photodegradation and hydrolysis) and biotic degradation test and applied it to a suite of 18 polymers, including ten lab produced, novel polyhydroxyalkanoate polyesters, and eight commercially available, bio-based (i.e., polylactic acid and poly-3-hydroxybutyrate) and fossil-derived (i.e., polystyrene, polypropylene, low density polyethylene, poly(ethylene terephthalate) and tire rubber) polymers. Biomineralization alone following standard methods (i.e., ASTM 6691-17, ISO 23977-1 2020) underestimated polymer degradation up to two-fold over 28 days. Simulated sunlight enhanced the overall polymer degradation by mobilizing dissolved organic carbon (DOC). After photoirradiation, up to 100% of released dissolved organic carbon was bioavailable for marine microbes over 14 days. Photodegradation and hydrolysis could be explained by structural drivers in the commodity polymers, and the lab-synthesized polymers illustrated a limit to total degradation beyond which no enhancements in degradation were achieved. Taken together, this workflow allows for relatively fast experimental determination of environmentally relevant stimuli to help support eventual elucidation of structure-property relationships for enhanced a priori design of degradable polymers.

Converting carbonyl index values in microplastics studies

The variability in carbonyl index (CI) calculation methods among studies has made direct comparison of CI values challenging. To address this, we developed a CI conversion methodology that enables the unification of CI values across studies. Using spectra data from environmental microplastic samples, a polynomial regression model was developed to convert predictor CI values into a target CI. The optimal model order was determined through five-fold cross-validation, which also demonstrated the model's ability to explain 36 %-84 % of the variance depending on the predictor CI method. The developed model was further applied to convert average CI values from different studies in coastal regions around Japan. Results revealed that microplastics in the southeast coastal regions of Japan are more oxidized than those in the west coastal regions, likely due to differences in environmental exposure and retention time. The developed methodology is also adaptable to CI calculation methods not explicitly covered in this study.

COVID-19 related personal protective equipment (PPE) litter in salt marsh habitats: Degradation and microplastic emission

The use of personal protective equipment (PPE) has increased significantly since the onset of the COVID-19 pandemic in late 2019. Face masks, gloves, and sanitizing wipes are common types of PPE that have been used during the pandemic, all of which can be comprised of plastic polymers. PPE items have been shown to generate microplastic fibers and fragments, but their degradation in the natural environment is understudied. The objective of this study was to quantify the degradation and microplastic emission of common plastic PPE items in a salt marsh, which serve a vital role in maintaining the health and resilience of coastal ecosystems and have been shown to be vulnerable to pollutants. Four types of PPE items (face masks, gloves, compostable and conventional sanitizing wipes) were deployed in an intertidal salt marsh for up to 16 weeks. Changes in weight, biofilm formation, surface area, and microplastic emissions were measured at 0, 2, 4, 8, and 16 weeks. All PPE degraded in the environment and emitted particles beginning at 2 weeks, and emission increased over time. Sanitizing wipes produced the highest number of microplastics at the end of 16-weeks. Compared to previous studies in the same area, these results suggest that plastic PPE items may degrade faster than other plastics. This study is one of the first to quantify PPE degradation and microplastic emission in the natural environment and supports the notion that single-use PPE litter has the potential to be a source of microplastic pollution in coastal environments.

Numerical modeling of the dispersion and accumulation of marine litter from the Dniester River in coastal areas of the northwestern Black Sea

This study investigates the transport and accumulation of Floating Marine Litter (FML) in the northwestern Black Sea, with a focus on the influence of the Dniester River and regional circulation patterns, including the Sevastopol Eddy. Two numerical modeling configurations (C1 and C2) are compared to assess their effectiveness in simulating FML dispersion. While both configurations show similar final beaching percentages, C2, which incorporates pre-calculated shoreline distances, can be more spatially accurate as it accounts for the complex shape of the coastline. The model's capability is validated through comparisons with previous models, satellite-derived Suspended Particulate Matter (SPM), and in situ observations from the 2017 EMBLAS campaign. These comparisons highlight FML accumulation patterns, particularly at the mouth of the Dniester River in the Zatoka region and in open waters within the Northwestern Shelf (NWS). The study suggests a correlation between satellite SPM observations and microplastic (MP) presence in coastal zones around the Dniester River, indicating avenues for future research. Understanding these dynamics is crucial for coastal management, with significant implications for environmental conservation strategies in the northwestern Black Sea.

Microplastics pollution in Gulf of Bandırma, Sea of Marmara: Biota and sediment

Plastic pollution has become a serious environmental problem on a global scale. Microplastics (MP), in particular, pose a significant threat to marine ecosystems. This study assesses the abundance, distribution, and characteristics of microplastics (MP) present in the Sea of Marmara, where the specimens of selected mollusk (Ostrea edulis, Mytilus galloprovincialis, Rapana venosa), fish (Mugil cephalus, Pomatomus saltatrix), and sediment were investigated. A total of 292 specimens were examined. Microplastics are ubiquitously distributed in all environmental matrices and averaged 2.6 ± 0.9 MP per individual in mollusks and 2.8 ± 1.0 MP per individual in fish. In sediment, microplastics ranged from 195 to 226 MP per kg dry weight. The most abundant microplastics are fibers, blue, and polyethylene terephthalate. The results indicate that microplastic pollution is widespread throughout the Sea of Marmara and may bioaccumulate the food web. Further research is necessary to determine the longer-term trends as well as the ecological impacts arising from this pollution. Monitoring studies of key bioindicators, including bivalves and fish, as well as sediment analysis, are required to understand and mitigate risks to this critical marine environment from microplastics.

Microplastic removal, identification and characterization in Chennai sewage treatment plants

Sewage treatment plants (STPs) act as either sinks or sources of microplastic (MP) contamination in the environment. This study examined and assessed the occurrence, removal efficiencies, abundance and characteristics of MPs in two STPs in Chennai, India. Large volumes of influent and effluent water were collected and filtered on site via a filter in a series system. The samples were later treated in the laboratory to isolate the MPs from other organic and inorganic particles. The MPs were analysed via Fourier Transform Infra-Red (FTIR) spectroscopy and Raman spectroscopy to analyse the chemical composition of the isolated microplastics. Pollution load index (PLI) and EU classification, labelling and packaging (CLP) standard was incorporated to assess the pollution risk of MPs in STP. According to the results obtained from this research work, the MP concentrations in the influent waters were high for both STPs (5443 MPs/L and 4800 MPs/L). Although the MP removal efficiency of the STPs were quite high (~96 % and ~93 %), the pollution load indices at Kodungaiyur and Koyambedu STPs were observed to be 0.272 and 0.208 respectively, which were moderately contaminated. PORI scores revealed that Kodungaiyur Plant is in danger level I with the hazard score of 9.25 and Koyambedu plant is in danger level II with the hazard score of 12.78. The estimated quantity of the MPs discharged from the monitored STPs was approximately 28.4 & 28.2 billion MPs/day.

Construction of a Real-Time Detection for Floating Plastics in a Stream Using Video Cameras and Deep Learning

Rivers act as natural conduits for the transport of plastic debris from terrestrial sources to marine environments. Accurately quantifying plastic debris in surface waters is essential for comprehensive environmental impact assessments. However, research on the detection of plastic debris in surface waters remains limited, particularly regarding real-time monitoring in natural environments following heavy rainfall events. This study aims to develop a real-time visual recognition model for floating plastic debris detection using deep learning with multi-class classification. A YOLOv8 algorithm was trained using field video data to automatically detect and count four types of floating plastic debris such as common plastics, plastic bottles, plastic film and vinyl, and fragmented plastics. Among the various YOLOv8 algorithms, YOLOv8-nano was selected to evaluate its practical applicability in real-time detection and portability. The results showed that the trained YOLOv8 model achieved an overall F1-score of 0.982 in the validation step and 0.980 in the testing step. Detection performance yielded mAP scores of 0.992 (IoU = 0.5) and 0.714 (IoU = 0.5:0.05:0.95). These findings demonstrate the model's robust classification and detection capabilities, underscoring its potential for assessing plastic debris discharge and informing effective management strategies. Tracking and counting performance in an unknown video was limited, with only 6 of 32 observed debris items detected at the counting line. Improving tracking labels and refining data collection are recommended to enhance precision for applications in freshwater pollution monitoring.

Comparison of macrolitter and meso- and microplastic pollution on French riverbanks and coastal beaches using citizen science with schoolchildren

Rivers are the major source of anthropogenic litter entering the ocean, especially plastic debris that accumulates in all ecosystems around the world and poses a risk to the biota. Reliable data on distribution, abundance, and types of stranded plastics are needed, especially on riverbanks that have received less attention than coastal beaches. Here, we present the citizen science initiative Plastique à la loupe (Plastic under the magnifier), which compares for the first time the distribution of different litter sizes (macrolitter and meso- and microplastics) over 81 riverbanks and 66 coastal beaches sampled in France between 2019 and 2021. A total of 147 school classes (3113 schoolchildren) from middle to high school collected, sorted, and enumerated 55,986 pieces of plastic to provide a baseline of the current pollution by stranded debris at the national level. Single-use plastics (mainly food-related items) were very abundant on riverbanks (43%), whereas fragmented debris dominated the macrolitter on coastal beaches (28%). Microplastics were always higher in number compared to mesoplastics and macrolitter, with polystyrene and polyethylene found in equivalent proportions on riverbanks while polyethylene dominated microplastics on coastal beaches. Tracing the source of plastic items was possible only for a small proportion of the numerous collected items, mainly for identifiable macrolitter and microplastic pellets. This study lays out the foundations for further works using the Plastique à la loupe citizen science initiative in France and additional comparisons to other studied habitats worldwide, which can be used by scientists and policy-makers for future litter monitoring, prevention and clean-up strategies.

Unseen threats along the coast and in underwater ecosystems of South Korea: The severity of marine debris entanglement

Plastic pollution threatens marine ecosystems, but research on interactions between plastic and marine fauna, especially entanglement at the national level is limited. This study aims to address this deficit by investigating marine fauna entanglement with marine debris in South Korean coastal and marine ecosystems. Comprehensive data were collected from government wildlife rescue centers, an online platform, internet searches, and scuba divers' underwater exploration descriptions. A total of 428 entanglement cases were documented (338 from coastal areas and 90 from underwater exploration) between 2003 and 2023. The analysis identified at least 77 affected species, including birds, sea turtles, marine mammals, fish, corals, and marine invertebrates. Overall, 13.0 % were listed as threatened or near threatened by the International Union for Conservation of Nature (IUCN) Global Red List, and 14.5 % were legally protected in Korea. The total number of entanglements considerably increased over time, especially in coastal regions. The sources of entanglement primarily involve monofilament lines and hooks associated with recreational fishing, as well as other fishing-related debris such as nets, ropes, and traps. These entanglements affect multiple groups of animals across different taxa. Our results support the need for stricter regulations and improved management of fishing activities to mitigate their impact on marine life. Future efforts should focus on enhancing data collection methods and integrating contributions from government agencies, associated organizations, and citizen scientists. Citizen scientist involvement will be particularly valuable for collecting data in less accessible underwater areas. Our findings may also apply to other large marine ecosystems with similar data deficits.

Heterotrophic feeding modulates the effects of microplastic on corals, but not when combined with heat stress

Plastic pollution is an increasing stressor adding pressure on coral reefs. Microplastic (MP) affects photosynthetic performance and growth of corals and may lead to bleaching. When corals are bleached and autotrophy is impaired, corals are more dependent on heterotrophic feeding to complement energy acquisition. While MP pollution is suspected to interfere with heterotrophic feeding, the effect of food availability on the tolerance of corals to MP pollution is still unknown. Here, we investigated how food availability affects the physiology of corals under MP pollution, by measuring coral growth, photophysiology, and tissue composition. Finally, we also investigated how the physiological response to MP and feeding are connected to bleaching susceptibility of the corals. To this end, we conducted a six-week aquarium experiment followed by a short-term heat stress phase with the coral species Pocillopora verrucosa and Stylophora pistillata exposed to three treatments: MP-free control and twice-weekly feeding (Control), MP-treatment and twice-weekly feeding (MP), and MP-treatment and daily feeding (MP + HF). Coral growth was similar across all treatments. However, MP treatment significantly decreased the tissue energy content of P. verrucosa, although it increased photosynthesis and respiration. High food availability partially mitigated the loss of tissue energy content observed in the MP treatment while maintaining photosynthesis and respiration rates comparable to control conditions. S. pistillata was not affected by MP exposure alone, but when combined with high feeding, photosynthesis decreased below that of the Control. When exposed to short-term heat stress, all corals bleached severely, however, both species bleached less in the MP treatment. These findings highlight that food availability and MP exposure elicit complex responses that influence the effect of other stressors such as heat stress. As MP continues to accumulate in rapidly warming oceans, further research is needed to understand the interactions between food availability and multivariate stressors on coral stress tolerance.

State of microbeads in facial scrubs: persistence and the need for broader regulation

Microbeads are small spherical plastic particles used as exfoliants in personal care products. Unfortunately, they have been found in the marine environment and are considered a significant contributor to global plastic pollution. In response, several countries have implemented microbead bans over the last few years. Here, we examined the exfoliant (scrubbing particles) composition of 28 facial scrubs from different regions in the presence and absence of microbead bans. We identified that over half of the exfoliant types identified in this study are microbeads, revealing the persistence of microbeads across various stages of microbead ban implementation. In regions with full bans, six out of eight products still contain microbeads, with some containing up to 6298 ± 1543 beads per gram of facial wash, suggesting the need for stronger legislation enforcement. We also identified challenges in distinguishing between microbeads composed of conventional plastics and synthetic waxes by Fourier-transform infrared spectroscopy. This study highlights the need to broaden the scope of microbead bans to include synthetic waxes, as they are not currently regulated. These findings underscore the importance of a broader and clearly articulated definition of microbeads in legislation to guide industry formulation and consumer choice of microbead-free products.

Transforming end-of-life fishing nets into solutions for sustainable infrastructure: A strategy for circular development

The inadequate management of end-of-life fishing nets generates serious environmental problems, affecting marine ecosystems and biodiversity. This study explores their reuse as modifiers in asphalt binders, promoting a circular economy model in road construction by improving recyclability. The results show that incorporating fishing nets (FN) increases the complex modulus (G∗), enhancing stiffness and resistance at high temperatures, particularly with 6% and 9% dosages. However, this increased stiffness may compromise fatigue resistance under cyclic loading and low temperatures. VECD simulation at 20 °C indicates that minimal FN incorporation reduces fatigue life by 40.61% at 5% strain. FN acts as a structural reinforcement, delaying damage in the binder and improving key properties such as flexibility and thermal resistance. Dosage adjustments and performance evaluations under real traffic and climatic conditions are necessary to optimize this technique to balance stiffness, elasticity, and durability. This approach reduces environmental impact and CO2 emissions associated with road maintenance and represents an advancement in the valorization of waste from the fishing sector. The incorporation of end-of-life fishing nets (FN) in asphalt binders opens up new research opportunities in mixes with recycled materials. This strategy encourages the use of plastic waste, aligning with the principles of the circular economy and contributing to the reduction of the environmental impact on road infrastructure.

Microplastic accumulation and histological effects on the Atlantic deep-sea scale-worm Laetmonice filicornis

Small benthic scavengers and carnivores, such as polychaetes, are very interesting to assess the accumulation and transfer of microplastics (MPs) to higher trophic levels in marine ecosystems. In this study we evaluate the presence, accumulation and impacts of MPs in the North-Atlantic deep-sea polychaete Laetmonice filicornis. Three types of MPs were identified: fishing lines, fibres and fragments, mostly black in colour, followed by red and blue ones. The average number of MPs was 4.10 ± 1.90 particles/g tissue. Fibres were the most abundant. They were composed of Polypropylene, Rayon, Polyethyleneimine Cellulose and Polyester. The histological analysis revealed the presence of microfibres embedded in muscles, peritoneum, nephridia, gonads and blood vessels, which can have a direct impact on vital functions, such as feeding and reproduction. This species occupies both predator and prey roles, bioaccumulate MPs and can transfer them to higher trophic links, representing a significant threat to all marine species, including humans.

Patterns and implications of plastic accumulation in mangrove ecosystems and sandy beaches in Western and Central regions of Ghana, West Africa

Plastic pollution has become increasingly apparent in sandy beach zones and aquatic environments, creating more than just visual pollution. Impacts are observed in many environmental and social levels, including the fishing communities that depend on the coastal environment for their livelihoods. Plastic pollution was assessed on the sandy beaches and mangroves of Ghana's Western and Central regions. The study's objective was to determine the composition, abundance and sources of plastic litter at four different sites during the wet and dry seasons. Samples were collected from within 50 cm2 quadrats placed randomly along four transects at each site. Plastic litter was classified according to the OSPAR guide. A total of 1895 plastic litter items with a combined weight of ~ 3000 g, representing 30 plastic categories, were collected. The average number and weight of plastic litter items were 19.73 ± 31.37 number of plastics per 50 cm2 and 32.59 ± 45.47 g per 50 cm2. The minimum and maximum plastic litter items were 0 to 159/50 cm2. The highest amount of plastic litter was found in Ghana's Central region. The total plastic litter weight is the variable that present statistical difference between the wet and dry season period. Bags, bottles, and fragments were the most common plastic items found, with 70% of the plastic litter being land-based, with the most frequent polymer types found in this study being polyethylene (~ 54%) and polypropylene (~ 20%). Mangrove regions act as sinks, specifically trapping plastic bags, contrary to the sandy beach areas, which mainly comprise plastic bottles that accumulate in these regions. Regions that have numerous communities, or are urbanised centres, tend to have higher levels or plastic litter. West Africa generally has poor waste management, absence of safe drinking water, and high levels of single-use plastics which are some of the main reasons for increased levels of plastic litter specifically in Ghana. Urgent actions are needed to prevent, mitigate and control plastic pollution in Ghana and the wider region.

Marine litter in the south-east of the Bay of Biscay: A review of current methods, standards, databases and challenges

Marine litter represents a significant global environmental challenge, in which plastics are considered the most concerning components. The widespread use of plastics, which exceeded 410 million tons in 2023, has led to a significant plastic litter accumulation in the oceans. The Bay of Biscay, characterized by its unique physical oceanography and intense human activities has been identified as a marine litter accumulation zone with litter densities in the same range of enclosed seas as the Mediterranean Sea. The purpose of this study is to provide a unique contribution to the south-east of the Bay of Biscay by collecting relevant information about marine macro litter, synthesizing the scientific outcomes for beaches, seafloor, and floating marine litter. In this region, beach litter density varies greatly depending on the beach and the time of year, with densities reaching 494 items/100 m. Litter density is influenced by factors such as wind, river flows, precipitation, or distance to ports or cities. In terms of floating marine litter, the Bay of Biscay is considered an accumulation zone influenced by wind patterns, with litter densities ranging from 0,16 to 3,13 items/km2. The seafloor is similarly impacted, with submarine canyons acting as sinks for marine litter and Arcachon Canyon (located in the studied area) as the second most polluted canyon of the entire Bay of Biscay with a record of 9,5 items per 100 images.

Micro- and nano-plastics pollution in the marine environment: Progresses, drawbacks and future guidelines

Marine pollution by micro/nanoplastics (M/NPs) has emerged as a critical global issue, with widespread ecological and economic consequences. Numerous studies have investigated M/NPs pollution in marine environments, but there remains a need to assess progress, identify challenges, and propose future strategies. This review provides updated insights into marine M/NPs, including their sources, detection methods, global data from diverse marine ecosystems, and the challenges in mitigating pollution. The review reveals that the ocean harbors approximately 5.25 trillion plastic debris pieces, with a total of 50-75 trillion plastic and microplastic particles, with deep-sea regions containing up to 4 billion plastic microfibers per square kilometer. Human activities, including industrial practices and aquaculture, are major contributors to M/NPs pollution, which threatens 17% of marine species and incurs an economic loss of 6-9 billion USD. M/NPs are found across various marine habitats, including shorelines, sea floors, water columns, biota, and floating debris. Analyzing nanoplastics is particularly challenging due to their heterogeneous aggregation with other contaminants and their much lower concentrations than natural particles. Key drawbacks in addressing M/NPs pollution include inadequate funding, insufficient regulations, and a lack of policy frameworks on the prevalence, distribution, and sources of M/NPs. There is an increasing focus on utilizing innovative technologies such as artificial intelligence (AI) to monitor, assess risks, and predict the spread of M/NPs. Therefore, urgent global cooperation, involving all stakeholders and the general public, is essential. Additionally, integrating scientific and engineering methods, along with AI technologies, is crucial for monitoring and controlling M/NPs pollution and developing sustainable solutions.

Runoff and accumulation of microplastics derived from polymer-coated fertilizer in Japanese paddy fields

Polymer-coated fertilizers, widely used in rice cultivation in Japan, contribute to reactive nitrogen management and agricultural productivity but are a source of microplastics in the environment. Here, we investigated microplastics derived from polymer-coated fertilizer (microcapsule) runoff in Japanese paddy fields at 38 sites to quantitatively assess the behavior of microcapsules in paddy fields and to estimate the total amount of runoff and accumulation in Japan. We also examined the factors causing variations in the amount of runoff among paddy fields. Between 61% and 100% of microcapsule runoff during the irrigation period occurred between puddling and rice transplanting, with concentrations ranging from 2-482 mg/m2 in paddy fields. Water management practices and wind direction and speed explained the difference in runoff between plots. The total amount of microcapsules discharged from Japanese paddy fields during the irrigation season was estimated to be between 17 and 6,291 t (median 1,157 t) from the loads obtained in this study. According to fertilizer statistics and our results, total microcapsule accumulation on agricultural land in Japan was estimated to be 75,623 t. These results suggest that paddy fields in Japan will remain a long-term source of marine microplastics.

Downsizing plastics, upsizing impact: How microplastic particle size affects Chironomus riparius bioturbation activity

Microplastic contamination in freshwater systems poses serious ecological risks, yet the role of particle size in shaping these impacts remains underexplored. This study investigates the influence of microplastic size on bioturbation activities of Chironomus riparius larvae, a process essential for sediment dynamics and nutrient cycling. Employing luminophore sediment profile imaging (LSPI), we tracked the vertical distribution of polyethylene particles within sediment layers, focusing on two distinct size ranges: small (53-63 μm) and large (250-300 μm) spherical particles. Microplastics (MPs) were introduced at a 0.076% sediment ratio to reflect natural exposure scenarios. Initial findings reveal that both particle sizes undergo downward transport, though with different patterns. Notably, smaller particles demonstrated a more pronounced effect on larval behaviour, appearing frequently in digestive tracts and suggesting increased bioavailability. Temporal analysis showed distinct reworking dynamics for each particle size, with larger particles exhibiting a delayed reworking time compared to the smaller particles. This highlights the critical influence of particle size on the fate and behaviour of MPs in freshwater systems, with smaller particles potentially posing a greater ecological risk due to their quicker and more active incorporation into sedimentary processes. This study provides critical insights into size-specific interactions between MPs and freshwater organisms, enhancing our understanding of their impacts on ecosystem health and sedimentary processes.

The effects of imidacloprid and polyester microfibers on the larval development of the endangered sunflower star

Sea star wasting syndrome has affected numerous species of sea star, with populations of Pycnopodia helianthoides (Brandt, 1835) left most at risk. As their populations are struggling to recover, it is important to gain a better understanding of the impacts that the multiple stressors in their habitats can have on their populations. Contaminant stressors in particular are of increasing importance, because aquatic organisms can be exposed to a dynamic range of contaminants from nearby anthropogenic activity that may affect their future recovery efforts. This study is the first to quantify the effects of contaminant stressors on the larvae of P. helianthoides. We exposed P. helianthoides larvae to the neonicotinoid insecticide imidacloprid and polyester microfibers, both individually and in combination, at environmentally relevant concentrations (10 ng/L and 25 fibers/L, respectively) to measure the effects of these contaminants on their early life stages. Imidacloprid exposure resulted in stomach malformation in 10% of larvae and increased mortality during early development (p < 0.001), and all treatments resulted in increased larval lengths relative to controls (p < 0.001). During settlement, imidacloprid resulted in more rapid settlement responses than in the controls (p < 0.01). These findings highlight the need for further research investigating the effects of contaminant stressors to endangered organisms during reintroduction as well as a more comprehensive understanding of the effects of pesticides to nontarget organisms.

From bulk to bits: understanding the degradation dynamics from plastics to microplastics, geographical influences and analytical approaches

The popularity of plastics in major application sectors is creating an increasing burden of pollutants in the environment in the forms of plastics and microplastics. More than 6 billion tons of plastics now reside in the environment, which is now an available source of secondary microplastics. Research focused on the degradation of plastics/microplastics dealing with different environmental conditions and their change in properties. Despite being a serious pollutant, sufficient resources are still missing for the transformation of secondary microplastics from large plastics and how to detect the level of degradation before this transition. This article's brief review provides insight into the current scenario of plastics, disposed waste plastics, management system, and their limitations. In addition, a detailed explanation of the transition of plastics to microplastics, their mechanism, and the effect of different geographical conditions on degradation is also demonstrated. Moreover, the available analytical techniques to understand the degradation index of different polymers are also described in addition to the future perspectives for research in this area. This review could provide valuable insight into the formation of microplastics from waste plastics and their mechanisms in addition to a comprehensive knowledge of the quantification of the degradation.

Exposure to polystyrene nanoplastics induces lysosomal enlargement and lipid droplet accumulation in KGN human ovarian granulosa cells

Given the ubiquitous presence of plastic products in daily life, human exposure to nanoplastics (NPs) is inevitable. Previous studies have suggested that exposure to polystyrene nanoplastics (PSNPs) may contribute to reproductive disorders; however, the underlying mechanism remains elusive. The goal of this study was to investigate the impact of PSNPs on KGN human ovarian granulosa cells. KGN cells were exposed to varying concentrations of PSNPs (0-400 μg/mL) for 48 h; alterations in cell survival and morphology were assessed to elucidate potential toxic effects. PSNPs were shown to enter KGN cells. Exposure to PSNPs did not induce significant changes in cytotoxicity, Calcein intensity, or active mitochondria levels in KGN cells. However, PSNP exposure did induce a dose-dependent increase in cytoplasmic vacuoles and an increase in total lysosome area and in the numbers of lipid droplets in KGN cells. Our findings provide compelling evidence that PSNPs can penetrate cell cytoplasm and induce toxicity, resulting in an elevation in the numbers of lysosomes and lipid droplets. This may represent one mechanism by which PSNPs exert damage on the reproductive system.

Comparative assessment of microplastic ingestion among deep sea decapods: Distribution analysis in Sardinian and Catalan waters

Microplastic (MP) pollution is a widespread and concerning environmental issue. The benthic layer is known as one of the major accumulation sinks, yet knowledge gaps still remain in describing the interactions of its biota with MPs. This work represents a comprehensive comparative analysis of MP ingestion in the four deep-sea crustacean decapods Aristeus antennatus (Risso, 1816), Aristaeomorpha foliacea (Risso, 1827), Nephrops norvegicus (Linnaeus, 1758) and Parapenaeus longirostris (Lucas, 1846) sampled from two distinct regions of the Mediterranean Sea in order to underscore the species-specific characteristics driving their MP ingestion variations. Results show that 72.5% of the individuals had ingested MPs, with fibers being the most common shape (91.36%), followed by tangles (8.64%). Catalan specimens had significantly higher fiber loads (mean; 3.69 fibers ind-1) than Sardinian ones (mean; 1.62 fibers ind-1), and distinct patterns among species were observed within the two regions. A. antennatus showed the highest MP load in the Catalan area whereas N. norvegicus was the most contaminated decapod in Sardinia. The observed variations are likely the result of a combination of factors, ranging from potentially different environmental exposure levels among regions to differences in the uptake and retention of MPs due to each species feeding ecology and morphological features. Overall, the results underscore the relevance of comprehensive assessments to properly interpret the trends in MP ingestion in crustacean decapods.