Marine mammals and microplastics: A systematic review and call for standardisation

Spatial distribution and risk assessment of microplastics in surface waters of the St. Lawrence Estuary

Development of effective prevention and mitigation strategies for marine plastic pollution requires a better understanding of the pathways and transport mechanisms of plastic waste. Yet the role of estuaries as a key interface between riverine inputs of plastic pollution and delivery to receiving marine environments remains poorly understood. This study quantified the concentration and distribution of microplastics (MPs) (50-3200 μm) in surface waters of the St. Lawrence Estuary (SLE) in eastern Canada. Microplastics were identified and enumerated based on particle morphology, colour, and size class. Fourier Transform Infrared (FTIR) spectroscopy was used on a subset of particles to identify polymers. Generalized linear models (Gamma distribution with log-link) examined the relationship between MP concentrations and oceanographic variables and anthropogenic sources. Finally, a risk assessment model, using MP concentrations and chemical hazards based on polymer types, estimated the MP pollution risk to ecosystem health. Mean surface MP concentration in the SLE was 120 ± 42 SD particles m-3; MP concentrations were highest in the fluvial section and lowest in the Northwest Gulf of St. Lawrence. However, MP concentrations exhibited high heterogeneity along the length and width of the SLE. Microplastics were elevated at stations located closer to wastewater treatment plant outflows and downstream sites with more agricultural land. Black, blue, and transparent fibers and fragments ≤250 μm were most commonly encountered. Predominant polymer types included polyethylene terephthalate, regenerated cellulose, polyethylene, and alkyds. While the overall risk to ecosystem health in the entire estuary was considered low, several stations, particularly near urban centres were at high or very high risk. This study provides new insights into the quantification and distribution of MPs and first estimates of the risk of MP pollution to ecosystem health in one of the world's largest estuaries.

Impacts of microplastic ingestion on fish communities in Haizhou Bay, China

Microplastics are pervasive throughout aquatic ecological communities. While their negative impacts on the life history traits of aquatic species are well studied, the effects on community dynamics remain elusive. Consequently, community-level assessments of microplastic effects on marine food webs are largely lacking, creating significant knowledge gaps regarding marine ecosystem structure and dynamics in the context of microplastic contamination. Here we expand a multispecies size-spectrum model by incorporating microplastic impacts on individual life-history traits, ultimately allowing us to study microplastic-mediated structural and functional changes in fish communities. As expected, microplastic ingestion may drive species extinction, but the microplastic-to-food ratio threshold for extinction is species-specific, and not necessarily correlated with species' asymptotic weights. Interestingly, species responses to microplastics also propagate through the community as ingestion triggers both bottom-up and top-down effects on community dynamics. Which specific type of cascading effect is dominating depends on which species is ingesting microplastics as well as its trophic role in the community. Generally, low-trophic-level species ingesting microplastics can exert large detrimental effects on community biomass. Thus, this study highlights the necessity for a comprehensive risk assessment of species-specific responses to microplastic contamination as well as an understanding of individual species' role in their communities.

Microplastics in marine sponges (Porifera) along a highly urbanized estuarine gradient in Santos, Brazil

Microplastics (MPs) are ubiquitously found in environmental matrices, particularly affecting aquatic systems. While several marine species have been widely used to assess MP contamination, sponges (Porifera) are less used. The MPs contamination was assessed in the sun sponge (Hymeniacidon heliophila) along a gradient at the Santos Estuarine System (Brazil). A 14-fold difference between concentrations (particles g-1) was verified between the most (1.40 ± 0.81) and least (0.10 ± 0.12) contaminated sites, confirming the local contamination gradient. The MPs found were primarily polypropylene, small (1.2-1000 μm), fibrous, and colored. Considering total concentrations, sizes and shapes these spatial patterns were similar those previously detected in molluscs obtained in the same sites. On the other hand, they differed in polymeric composition and color categories. Such findings give important initial insights into the potential role of marine sponges as putative sentinels of MPs contamination.

The quantifying, mapping, and risk analysis of human-related stressors in the high seas

Objectives: Marine biodiversity and ecosystem services in the high seas are threatened by numerous stress factors caused by human activities, including global shipping, high-sea fishing, marine plastic pollution, and anthropogenic climate change. Socioeconomic factors are one of the criteria for the establishment of area-based management tools in the high seas for marine biodiversity conservation beyond national jurisdiction. The aim of the work is to propose a spatiotemporal approach to identify risks from marine human activities and recommendations for high seas governance. Methods: Data related to human activities from 2014 to 2022 were used to calculate the distribution and changes of human-related stressors, and the risk to marine biodiversity in the high seas caused by human activities. Results: The North Atlantic, Philippine Sea, Arabian Sea, Bay of Bengal, and East Central Atlantic show high and increasing intensities of human-related stressors, and are therefore particularly at need for the protection and conservation of marine biodiversity. Risks from human activities vary within the marine areas that are prioritized for biodiversity protection. The study recommends that the designation of high seas protected areas should take into account the types of risks to which the different marine areas are exposed, and that the high seas protected areas should be established gradually. At the same time, appropriate management measures should be formulated according to the intensity of human activities in the different marine areas. Conclusions: Quantifying and classifying the risk from human-related stressors could help identify solution for the protection and conservation and facilitate the marine spatial planning, establishment area based management tools, including marine protected areas in the high seas.

Microplastics and low tide warming: Metabolic disorders in intertidal Pacific oysters (Crassostrea gigas)

Sessile intertidal organisms live in a harsh environment with challenging environmental conditions and increasing anthropogenic pressure such as microplastic (MP) pollution. This study focused on effects of environmentally relevant MP concentrations on the metabolism of intertidal Pacific oyster Crassostrea gigas, and its potential MP-induced vulnerability to warming during midday low tide. Oysters experienced a simulated semidiurnal tidal cycle based on their natural habitat, and were exposed to a mixture of polystyrene microbeads (4, 7.5 and 10 µm) at two environmentally relevant concentrations (0.025 µg L-1 and 25 µg L-1) for 16 days, with tissue samplings after 3 and 12 days to address dose-dependent effects over time. On the last day of exposure, the remaining oysters were additionally exposed to low tide warming (3 °C h-1) to investigate possible MP-induced susceptibility to aerial warming. Metabolites of digestive gland and gill tissues were analysed by using untargeted 1H nuclear magnetic resonance (NMR) based metabolomics. For the digestive gland metabolite profiles were comparable to each other independent of MP concentration, exposure time, or warming. In contrast, gill metabolites were significantly affected by high MP exposure and warming irrespective of MP, initiating the same cellular stress response to counteract induced oxidative stress. The activated cascade of antioxidant defence mechanisms required energy on top of the general energy turnover to keep up homeostasis, which in turn may lead to subtle, and likely sub-lethal, effects within intertidal oyster populations. Present results underline the importance of examining the effects of environmentally relevant MP concentrations not only alone but in combination with other environmental stressors.

Topic modeling discovers trending topics in global research on the ecosystem impacts of microplastics

The ecological threats of microplastics (MPs) have sparked research worldwide. However, changes in the topics of MP research over time and space have not been evaluated quantitatively, making it difficult to identify the next frontiers. Here, we apply topic modeling to assess global spatiotemporal dynamics of MP research. We identified nine leading topics in current MP research. Over time, MP research topics have switched from aquatic to terrestrial ecosystems, from distribution to fate, from ingestion to toxicology, and from physiological toxicity to cytotoxicity and genotoxicity. In most of the nine leading topics, a disproportionate amount of independent and collaborative research activity was conducted in and between a few developed countries which is detrimental to understanding the environmental fates of MPs in a global context. This review recognizes the urgent need for more attention to emerging topics in MP research, particularly in regions that are heavily impacted but currently overlooked.

Marine mammals as indicators of Anthropocene Ocean Health

The current state of marine mammal populations reflects increasing anthropogenic impacts on the global Ocean. Adopting a holistic approach towards marine mammal health, incorporating healthy individuals and healthy populations, these taxa present indicators of the health of the overall Ocean system. Their present deterioration at the animal, population and ecosystem level has implications for human health and the global system. In the Anthropocene, multiple planetary boundaries have already been exceeded, and quiet tipping points in the Ocean may present further uncertainties. Long and short-term monitoring of marine mammal health in the holistic sense is urgently required to assist in evaluating and reversing the impact on Ocean Health and aid in climate change mitigation.

Microplastic characterization in the stomachs of swordfish (Xiphias gladius) from the western Mediterranean Sea

In this study, we aimed to quantify the presence of microplastics (MPs) in the stomachs of large pelagic fish (swordfish, Xiphias gladius, Linnaeus, 1758) sampled in the western Mediterranean Sea, and assess temporal trends (2011-2012 vs. 2017-2019) in MP ingestion. MPs were extracted from stomachs and characterized by μ-Fourier transform infrared spectroscopy. Results highlighted the ingestion of MP in 39 out of 49 stomachs analysed. Ingested MPs consisted mostly of small (<1 mm) fibers (88.6 %, mean ± standard deviation = 2.5 ± 6.1 particles per stomach), with a greater frequency of occurrence (FO) in the second period (FO = 90 %, 3.3 ± 8.0 particles per stomach). The predominant colours were purple, black and blue, and polyethylene terephthalate was the most frequently detected polymer. These results are crucial for the development of management actions aimed at the conservation of swordfish in the Mediterranean Sea and the prevention of health risks to humans.

Detection of microplastics in zebrafish housing systems: Can microplastic background contamination affect the final results of microplastic-related toxicological tests?

Concentrations of microplastics (MPs) were determined in three commonly used zebrafish housing systems to see if their levels could affect the final results of laboratory microplastic-related toxicology tests. MPs have received notable attention in the last few years, and their toxicology tests have also come to the fore. Zebrafish (Danio rerio), kept in fish housing systems, are widely used as models for MPs studies. Most of these systems contain a significant number of parts made of different polymers. As usage and amortization can erode these parts, MPs might appear in the keeping water or the fish body, which may represent a background load and possibly influence the results of microplastic-related toxicological tests. To take representative water samples from systems, two in-situ filtration techniques, a newly developed peristaltic pump-, and a jet pump-driven method were applied. The collected MP particles were analyzed with a Fourier-transform infrared microscope (detection limit 50 μm), and their possible origin was also investigated. The newly developed technique was more sufficient for sampling as it had a higher MPs recovery, especially in the smaller size range. Polyester, polyethylene and polypropylene were the most frequently detected polymers in the examined fish housing systems, the highest detected concentration was 0.31±0.12 particles/liter (0.22±0.16 μg/liter). These values are negligible compared to the literature data reporting enormously high applied MPs concentrations (104 - 2.21 × 108 particles/liter) during toxicology tests. The results also show that some detected MPs did not originate from the systems, their origin was presumed to be external.

Primary Microplastics in the Ecosystem: Ecological Effects, Risks, and Comprehensive Perspectives on Toxicology and Detection Methods

Recent discoveries of microplastics in cities, suburbs, and even remote locations, far from microplastic source regions, have raised the possibility of long-distance transmission of microplastics in many ecosystems. A little is known scientifically about the threat that it posed to the environment by microplastics. The problem's apparent size necessitates the rapid development of reliable scientific advice regarding the ecological risks of microplastics. These concerns are brought on by the lack of consistent sample and identification techniques, as well as the limited physical analysis and understanding of microplastic pollution. This review provides insight regarding some unaddressed issues about the occurrence, fate, movement, and impact of microplastics, in general, with special emphasis on primary microplastics. The approaches taken in the earlier investigations have been analyzed and different recommendations for future research have been suggested.

Beyond surface: Unveiling ecological and economic ramifications of microplastic pollution in the oceans

Every year, the global production of plastic waste reaches a staggering 400 million metric tons (Mt), precipitating adverse consequences for the environment, food safety, and biodiversity as it degrades into microplastics (MPs). The multifaceted nature of MP pollution, coupled with its intricate physiological impacts, underscores the pressing need for comprehensive policies and legislative frameworks. Such measures, alongside advancements in technology, hold promise in averting ecological catastrophe in the oceans. Mandated legislation represents a pivotal step towards restoring oceanic health and securing the well-being of the planet. This work offers an overview of the policy hurdles, legislative initiatives, and prospective strategies for addressing global pollution due to MP. Additionally, this work explores innovative approaches that yield fresh insights into combating plastic pollution across various sectors. Emphasizing the importance of a global plastics treaty, the article underscores its potential to galvanize collaborative efforts in mitigating MP pollution's deleterious effects on marine ecosystems. Successful implementation of such a treaty could revolutionize the plastics economy, steering it towards a circular, less polluting model operating within planetary boundaries. Failure to act decisively risks exacerbating the scourge of MP pollution and its attendant repercussions on both humanity and the environment. Central to this endeavor are the formulation, content, and execution of the treaty itself, which demand careful consideration. While recognizing that a global plastics treaty is not a panacea, it serves as a mechanism for enhancing plastics governance and elevating global ambitions towards achieving zero plastic pollution by 2040. Adopting a life cycle approach to plastic management allows for a nuanced understanding of possible trade-offs between environmental impact and economic growth, guiding the selection of optimal solutions with socio-economic implications in mind. By embracing a comprehensive strategy that integrates legislative measures and technological innovations, we can substantially reduce the influx of marine plastic litter at its sources, safeguarding the oceans for future generations.

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

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

Microplastics contamination in water supply system and treatment processes

Due to global demand, millions of tons of plastics have been widely consumed, resulting in the widespread entry of vast amounts of microplastic particles into the environment. The presence of microplastics (MPs) in water supplies, including bottled water, has undergone systematic review, assessing the potential impacts of MPs on humans through exposure assessment. The main challenges associated with current technologies lie in their ability to effectively treat and completely remove MPs from drinking and supply water. While the risks posed by MPs upon entering the human body have not yet been fully revealed, there is a predicted certainty of negative impacts. This review encompasses a range of current technologies, spanning from basic to advanced treatments and varying in scale. However, given the frequent detection of MPs in drinking and bottled water, it becomes imperative to implement comprehensive management strategies to address this issue effectively. Consequently, integrating current technologies with management options such as life-cycle assessment, circular economy principles, and machine learning is crucial to eliminating this pervasive problem.

Assessing the current state of plastic pollution research in Antarctica: Knowledge gaps and recommendations

Antarctica stands as one of the most isolated and pristine regions on our planet. Regardless, recent studies have evidenced the presence of plastic pollution in Antarctic environments and biota. While these findings are alarming and put into perspective the reach of plastic pollution, it is necessary to assess the current knowledge of plastic pollution in Antarctica. In the present review, an updated literature review of plastic pollution in multiple Antarctic environmental compartments and biota was conducted. Studies were cataloged based on environmental compartments (e.g., sediments, seawater, soil, atmosphere) and biota from different ecological niches. A detailed analysis of the main findings, as well as the flaws and shortcomings across studies, was conducted. In general terms, several studies have shown a lack of adequate sampling and analytical procedures for plastic research (particularly in the case of microplastics) and standard procedures; thus, compromising the reliability of the data reported and comparability across studies. Aiming to guide future studies and highlight research needs, a list of knowledge gaps and recommendations were provided based on the analysis and discussion of the literature and following standardized procedures.

A systematic review of robotic efficacy in coral reef monitoring techniques

Coral reefs are home to a variety of species, and their preservation is a popular study area; however, monitoring them is a significant challenge, for which the use of robots offers a promising answer. The purpose of this study is to analyze the current techniques and tools employed in coral reef monitoring, with a focus on the role of robotics and its potential in transforming this sector. Using a systematic review methodology examining peer-reviewed literature across engineering and earth sciences from the Scopus database focusing on "robotics" and "coral reef" keywords, the article is divided into three sections: coral reef monitoring, robots in coral reef monitoring, and case studies. The initial findings indicated a variety of monitoring strategies, each with its own advantages and disadvantages. Case studies have also highlighted the global application of robotics in monitoring, emphasizing the challenges and opportunities unique to each context. Robotic interventions driven by artificial intelligence and machine learning have led to a new era in coral reef monitoring. Such developments not only improve monitoring but also support the conservation and restoration of these vulnerable ecosystems. Further research is required, particularly on robotic systems for monitoring coral nurseries and maximizing coral health in both indoor and open-sea settings.

First determination of elevated levels of plastic additives in finless porpoises from the South China Sea

Plastic additives, such as organophosphate esters (OPEs) and phthalate esters (PAEs), are raising public concerns due to their widespread presence and potential health risks. Nonetheless, the occurrences and potential health risks of these additives in marine mammals remain limited. Here, we first investigated the accumulation patterns and potential risks of OPEs and metabolites of PAEs (mPAEs) in Indo-Pacific finless porpoises inhabiting the northern South China Sea (NSCS) during 2007-2020. The average hepatic concentrations of ∑15OPEs and ∑16mPAEs in the NSCS finless porpoises were 53.9 ± 40.7 and 98.6 ± 54.8 ng/g ww, respectively. The accumulation of mPAEs and OPEs in the finless porpoises is associated with the chemical structures of the compounds. ∑5halogenated-OPEs were the most dominant category (62.6%) of ∑15OPEs, followed by ∑6aryl-OPEs (25.9%) and ∑6nonhalogenated alkyl-OPEs (11.5%). The accumulation of mPAEs displayed a declining trend with increasing alkyl side chain length (C0-C10). Although the hepatic burden of mPAEs in finless porpoises was sex-independent, some OPEs, including TDCIPP, TBOEP, TCIPP, TCrP, TPHP, and TDBPP, exhibited significantly higher concentrations in adult males than in adult females. TDBPP, as a new-generation OPE, exhibited a gradual increase during the study period, suggesting that TDBPP should be prioritized for monitoring in the coastal regions of South China. The estimated hazard quotient indicated that almost all mPAEs and OPEs pose no hazard to finless porpoises, with only DEHP presenting potential health risks to both adult and juvenile finless porpoises.

Tracking anthropogenic microparticles in wildlife of an alpine insular environment

Despite the isolation of remote natural regions, it has been discovered that they are experiencing the accumulation of anthropogenic microparticles (i.e., microplastics or natural or semisynthetic cellulosic particles). Teide National Park (Canary Islands, Spain) is a high-mountain protected area known for its rich biodiversity. This study aims to assess the occurrence of coloured anthropogenic particles in the faecal matter of wild mammals, specifically rabbits and mouflons, residing in the park. With this purpose, faeces were collected from 68 systematically distributed sampling points. A stereomicroscopy-guided grinding process allowed a chemical-free and quick visual inspection of 616 individual excreta, revealing that 96% were particle-free. However, 37 anthropogenic particles were found, which correspond to 0.79 ± 0.20 items per gram of dry faecal matter. The archetypical particle was a cellulosic blue microfibre of 2721 ± 407 µm, though poly(ethylene-vinyl acetate) and polypropylene were also identified via micro Fourier-transform infrared spectroscopic analysis. Atmospheric deposition and touristic pressure may be the sources of the anthropogenic particles, as they were randomly found in 36% of the sampling points. These findings represent the first evidence of anthropogenic particle ingestion by wild rabbits and mouflons, signifying the introduction of microplastics into terrestrial food chains in a remote high-mountain environment.

Microplastics in the stomach content of the commercial fish species Scomber colias in the Gulf of Cadiz, SW Europe

Concerning microplastics (MPs) contamination is increasing due their negative impacts on marine food webs and their potential toxicity to wildlife and humans. In this study, we analyze the presence of MPs in the stomachs of the commercial fish species Scomber colias (Atlantic chub mackerel) in the Gulf of Cadiz (GoC). Out of the 104 analyzed stomachs, 90.4 % contained some type of MPs, with an average of 5.4 MPs per individual. Of the 1152 MPs analyzed, 91.1 % were fibers, and 8.9 % fragments type. Fourier Transformation Infrared Spectrometry analysis was performed on 152 items, revealing that 73.6 % were MPs. The most common synthetic polymers found were polyamide (64 %), polypropylene (15 %), polystyrene (12 %), polyvinyl chloride (5 %), and polyethylene (4 %). The consistent ingestion of synthetic polymers by the individuals of Atlantic chub mackerel across different zones might suggest an even distribution of MP contamination throughout the GoC.

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

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

Identification and characterization of plastic debris in the gastrointestinal tract of Guiana dolphins (Sotalia guianensis) from Espírito Santo coast, Brazil

The Guiana dolphin (Sotalia guianensis) is categorized as vulnerable in the Brazilian list of endangered animals, and its populations suffer from several anthropological threats. In this study, we analyzed the presence of macro, meso, and microplastics (MPs) in Guiana dolphins (n = 12) in Brazil Southeastern coast by analysing their gastrointestinal tract. The MP extractions were carried out with H2O2 (35 %) to remove organic matter. Four specimens ingested meso and macroplastics, including an item of polypropylene of 19.22 cm that was produced about 943 km from the place in which the animal was found stranded. All the specimens analyzed had fragment-type microplastics in their intestines. Blue was the prevailing color, followed by black, green, and red. We highlight the contamination by microplastics in the species, still little investigated, especially the need to understand the contamination by microplastics along trophic levels.

Microplastics Prevalence in Different Cetaceans Stranded along the Western Taiwan Strait

Microplastics (MPs) pollution is of global concern, which poses serious threats to various marine organisms, including many threatened apex predators. In this study, MPs were investigated from nine cetaceans of four different species, comprising one common dolphin (Delphinus delphis), two pygmy sperm whales (Kogia breviceps), one ginkgo-toothed beaked whale (Mesoplodon ginkgodens), and five Indo-Pacific humpback dolphins (Sousa chinensis) stranded along the western coast of the Taiwan Strait from the East China Sea based on Fourier transform infrared (FTIR) spectroscopy analysis. Mean abundances of 778 identified MPs items were 86.44 ± 12.22 items individual-1 and 0.43 ± 0.19 items g-1 wet weight of intestine contents, which were found predominantly to be transparent, fiber-shaped polyethylene terephthalate (PET) items usually between 0.5 and 5 mm. The abundance of MPs was found at a slightly higher level and significantly correlated with intestine contents mass (p = 0.0004*). The MPs source was mainly likely from synthetic fibers-laden sewage discharged from intense textile industries. Our report represents the first study of MPs in pelagic and deep-diving cetaceans in China, which not only adds baseline data on MPs for cetaceans in Asian waters but also highlights the further risk assessment of MPs consumption in these threatened species.

Modelling microplastic bioaccumulation and biomagnification potential in the Galápagos penguin ecosystem using Ecopath and Ecosim (EwE) with Ecotracer

Bioaccumulation and biomagnification of anthropogenic particles are crucial factors in assessing microplastic impacts to marine ecosystems. Microplastic pollution poses a significant threat to iconic and often endangered species but examining their tissues and gut contents for contaminant analysis via lethal sampling is challenging due to ethical concerns and animal care restrictions. Incorporating empirical data from prey items and fecal matter into models can help trace microplastic movement through food webs. In this study, the Galápagos penguin food web served as an indicator species to assess microplastic bioaccumulation and biomagnification potential using trophodynamic Ecopath with Ecosim (EwE) modelling with Ecotracer. Empirical data collected from surface seawater near Galápagos penguin colonies, zooplankton, penguin prey, and penguin scat in October 2021 were used to inform the ecosystem model. Multiple scenarios, including a 99% elimination rate, were employed to assess model sensitivity. Model predictions revealed that microplastics can bioaccumulate in all predator-prey relationships, but biomagnification is highly dependent on the elimination rate. It establishes the need for more research into elimination rates of different plastics, which is a critical missing gap in current microplastic ecotoxicological and bioaccumulation science. Compared to empirical data, modelling efforts underpredicted microplastic concentrations in zooplankton and over-predicted concentrations in fish. Ultimately, the ecosystem modelling provides novel insights into potential microplastics' bioaccumulation and biomagnification risks. These findings can support regional marine plastic pollution management efforts to conserve native and endemic species of the Galápagos Islands and the Galápagos Marine Reserve.

Microplastics in Ecuador: A review of environmental and health-risk assessment challenges

Pollution from plastic debris and microplastics (MPs) is a worldwide issue. Classified as emerging contaminants, MPs have become widespread and have been found not only in terrestrial and aquatic ecosystems but also within the food chain, which affects both the environment and human health. Since the outbreak of COVID-19, the consumption of single-use plastics has drastically increased, intensifying mismanaged plastic waste in countries such as Ecuador. Therefore, the aim of this review is to 1) summarize the state of MP-related knowledge, focusing on studies conducted with environmental matrices, biota, and food, and 2) analyze the efforts by different national authorities and entities in Ecuador to control MP contamination. Results showed a limited number of studies have been done in Ecuador, which have mainly focused on the surface water of coastal areas, followed by studies on sediment and food. MPs were identified in all samples, indicating the lack of wastewater management policies, deficient management of solid wastes, and the contribution of anthropogenic activities such as artisanal fishing and aquaculture to water ecosystem pollution, which affects food webs. Moreover, studies have shown that food contamination can occur through atmospheric deposition of MPs; however, ingredients and inputs from food production, processing, and packaging, as well as food containers, contribute to MP occurrence in food. Further research is needed to develop more sensitive, precise, and reliable detection methods and assess MPs' impact on terrestrial and aquatic ecosystems, biota, and human health. In Ecuador specifically, implementing wastewater treatment plants in major cities, continuously monitoring MP coastal contamination, and establishing environmental and food safety regulations are crucial. Additionally, national authorities need to develop programs to raise public awareness of plastic use and its environmental effects, as well as MP exposure's effects on human health.

Legacy and emerging contaminants in marine mammals from Argentina

Marine mammals are recognized sentinels of ecosystem health. They are susceptible to the accumulation and biomagnification of pollutants, which constitute one of the greatest threats to their survival. Legacy, such as organochlorine pesticides, and emerging contaminants, like microplastics and pharmaceuticals, may have effects on marine mammals' health at individual and population levels. Therefore, the evaluation of the risks associated with pollutants in this group is of great importance. The aim of this review is to provide information on the occurrence of legacy and emerging contaminants in marine mammals that inhabit Argentine waters. Also, to identify knowledge gaps and suggest best practices for future research. Reports of legacy contaminants referring to organochlorine pesticides and polychlorinated biphenyls were found in five species of cetaceans and two of pinnipeds. With respect to emerging pollutants, the presence of plastics was only evaluated in three species. Reported data was from at least a decade ago. Therefore, it is necessary to update existing information and conduct continuous monitoring to assess temporary trends in pollutants. All the studies were carried out in the province of Buenos Aires and Northern Patagonia indicating a knowledge gap in the southern zone of the Argentine Sea. In addition, pollutants of global environmental concern that have not been studied in Argentina are discussed. Future studies should fill these gaps and a greater effort to understand the relationships between pollutants and their effects on marine mammals is suggested. This issue will make it possible to determine thresholds for all the substances and species evaluated in order to carry out more detailed risk assessments and make decisions for the conservation of marine mammals in Argentine waters.

Swimming behavior affects ingestion of microplastics by fish

Microplastics (< 5 mm) are widely found in organisms and have the potential harm to ecosystems. Despite their widespread prevalence in environments, there is high individual varation in the abundance of microplastics found in individuals of the same species. In the present study, juvenile cichlid fish (Chindongo demasoni) were chosen to determine the ingestion personality for microplastics in the laboratory. The visible implant fluorescent tags were used for individual recognition. The fish were fed with microplastic fiber, pellet, and food for comparison. Our results showed that the observation of the behaviors of fish could be successfully matched with subsequent measurements for each individual through the tag method in microplastic research. The difference in the abundance of fiber (0-27 items/ind.) among fish individuals was also observed in our study. Meanwhile, the abundance of fiber showed a positive correlation with the average speed and covered area of fish, which indicates the degree of activity of fish. Moreover, fish with higher speed or a front position had higher capturing times for pellet. Our results suggest that the swimming behaviors of fish affect their ingestion of microplastics, and active fish had a higher likelihood of ingesting microplastics, which might be one of the reasons for the common phenomena, i.e., great individual differences observed in microplastic studies.

Tackling microplastics pollution in global environment through integration of applied technology, policy instruments, and legislation

Microplastic pollution is a serious environmental problem that affects both aquatic and terrestrial ecosystems. Small particles with size of less than 5 mm, known as microplastics (MPs), persist in the environment and pose serious threats to various species from micro-organisms to humans. However, terrestrial environment has received less attention than the aquatic environment, despite being a major source of MPs that eventually reaches water body. To reflect its novelty, this work aims at providing a comprehensive overview of the current state of MPs pollution in the global environment and various solutions to address MP pollution by integrating applied technology, policy instruments, and legislation. This review critically evaluates and compares the existing technologies for MPs detection, removal, and degradation, and a variety of policy instruments and legislation that can support the prevention and management of MPs pollution scientifically. Furthermore, this review identifies the gaps and challenges in addressing the complex and diverse nature of MPs and calls for joint actions and collaboration from stakeholders to contain MPs. As water pollution by MPs is complex, managing it effectively requires their responses through the utilization of technology, policy instruments, and legislation. It is evident from a literature survey of 228 published articles (1961-2023) that existing water technologies are promising to remove MPs pollution. Membrane bioreactors and ultrafiltration achieved 90% of MPs removal, while magnetic separation was effective at extracting 88% of target MPs from wastewater. In biological process, one kg of wax worms could consume about 80 g of plastic/day. This means that 100 kg of wax worms can eat about 8 kg of plastic daily, or about 2.9 tons of plastic annually. Overall, the integration of technology, policy instrument, and legislation is crucial to deal with the MPs issues.

Are Microplastics a Macro Issue? A Review on the Sources of Contamination, Analytical Challenges and Impact on Human Health of Microplastics in Food

In recent years, human populations' exposure to microplastics via foods is becoming a topic of concern. Although microplastics have been defined as "emerging contaminants", their occurrence in the environment and food is quite dated. This systematic review aims to investigate the discrepancies which are characterizing the research in the microplastics field in foods, with particular regard to sample preparations, microplastics' concentrations and their effect on humans. For the selection of papers, the PRISMA methodology was followed. Discrepancies in the methodological approaches emerged and in the expression of the results as well, underlying the urgency in the harmonization of the methodological approaches. Uncertainties are still present regarding the adverse effects of microplastics on the human body. The scientific evidence obtained thus far is, in fact, not sufficient to demonstrate a concrete negative effect. This review has clearly underlined the need to standardise laboratory approaches to obtain useful results for better food safety management.

Detection and quantification of microplastic pollution in the endangered Galapagos sea lion

Marine debris pollution poses a significant global threat to biodiversity, with plastics being the primary debris type found in oceans due to their low-cost production and high demand worldwide. Microplastics (MPs, <5 mm in size) are highly bioavailable to a wide range of marine taxa, including marine mammals, through direct and indirect ingestion routes (i.e., trophic transfer). Recently, MP pollution has been detected on the Galapagos Marine Reserve, so in this study we developed a baseline framework for MP pollution in the Galapagos sea lion (GSL, Zalophus wollebaeki) through scat-based analysis. We collected 180 GSL scat samples from the southeast region following strict quality assurance/quality control protocols to detect, quantify and characterize physical-chemical properties of MPs through visual observations and μFT-IR spectroscopy. We recovered 81 MPs of varying sizes and colors in 37 % of samples (n = 66/180), consisting mostly of fibers (69 %, x¯ = 0.31 ± 0.57 particles scat-1). The number of particles per gram of sample wet weight ranged from 0.02 to 0.22 (x¯ = 0.04 ± 0.05 particles scat wet g-1). El Malecón and Punta Pitt rookeries at San Cristobal Island had the highest number of MPs (x¯ = 0.67 ± 0.51 and 0.43 ± 0.41 particles scat-1, respectively), and blue-colored particles were the most common in all samples. We identified eleven polymers in 46 particles, consisting mostly of polypropylene-polyethylene copolymer, polypropylene, cellulose, polyethylene, and polyvinyl chloride. The textile, fishing, and packaging industries are likely significant sources of microfibers into this insular ecosystem. Our results suggest that the GSL is exposed to MPs due to anthropogenic contamination that is subsequently transferred through trophic processes. These findings provide an important baseline framework and insights for future research on MP pollution in the region, as well as for management actions that will contribute to the long-term conservation of the GSL.

Microplastics in marine mammal blubber, melon, & other tissues: Evidence of translocation

Marine mammals consume large quantities of microplastic particles, likely via trophic transfer (i.e., through prey who have consumed plastic) and direct consumption from seawater or sediment. Microplastics have been found in the stomachs, gastro-intestinal tracts, and feces of cetaceans and pinnipeds. Translocation of ingested microplastics has been documented in other organs of several aquatic species, but has not been examined in marine mammals. Marine mammals have highly specialized lipid-rich tissues which may increase susceptibility to lipophilic microplastics. Here we demonstrate the occurrence of microplastics, ranging in size, mass concentration, and particle count concentration from 24.4 μm - 1387 μm, 0.59 μg/g - 25.20 μg/g, and 0.04 - 0.39 particles/g, respectively, in four tissues (acoustic fat pad, blubber, lung, & melon) from twelve marine mammal species inclusive of mysticetes, odontocetes, and phocids. Twenty-two individuals were examined for microplastics using a combination of Raman spectroscopy and pyrolysis gas chromatography with mass spectrometry. Overall, 68% of individuals had at least one microplastic particle in at least one of the four tissue types, with the most common polymer and shape observed being polyethylene and fibers, respectively. These findings suggest some proportion of ingested microplastics translocate throughout marine mammal bodies posing an exposure risk to both marine mammals and people. For people, exposure could be directly through consumption for those who rely on marine mammals as food and indirectly to peoples globally who consume the same prey resources as marine mammals. Some individuals examined represent samples obtained over two decades ago, suggesting that this process, and thus exposure risk, has occurred for some time.

Impact of chemical pollution on threatened marine mammals: A systematic review

Marine mammals, due to their long life span, key position in the food web, and large lipid deposits, often face significant health risks from accumulating contaminants. This systematic review examines published literature on pollutant-induced adverse health effects in the International Union for Conservation of Nature (IUCN) red-listed marine mammal species. Thereby, identifying gaps in literature across different extinction risk categories, spatial distribution and climatic zones of studied habitats, commonly used methodologies, researched pollutants, and mechanisms from cellular to population levels. Our findings reveal a lower availability of exposure-effect data for higher extinction risk species (critically endangered 16%, endangered 15%, vulnerable 66%), highlighting the need for more research. For many threatened species in the Southern Hemisphere pollutant-effect relationships are not established. Non-destructively sampled tissues, like blood or skin, are commonly measured for exposure assessment. The most studied pollutants are POPs (31%), metals (30%), and pesticides (17%). Research on mixture toxicity is scarce while pollution-effect studies primarily focus on molecular and cellular levels. Bridging the gap between molecular data and higher-level effects is crucial, with computational approaches offering a high potential through in vitro to in vivo extrapolation using (toxico-)kinetic modelling. This could aid in population-level risk assessment for threatened marine mammals.

Microplastic ingestion by invasive Prussian carp (Carassius gibelio) used in fishmeal production in Türkiye

MP contamination in the gastrointestinal tract (GIT) of Prussian carp (Carassius gibelio) used in fishmeal production was examined. The samples were collected from Balık Lake, Karaboğaz Lake, and Liman Lake located in Kızılırmak Delta, Türkiye. The overall average abundance was 3.20±0.18 MP per fish and 0.036±0.002 MP per g. No significant correlation was determined between the MP abundance in the fish, fish length, and fish weight. The polymers were composed of 56.91% PET, 25.20% PP, 9.76% PE, and 8.13% PA. The determined shapes were fiber (78.0%), fragment (13.46%), and film (8.54%). The size ranged between 112 and 4775 μm with an average of 1341.41±66.07 μm. Depending on the occurrence frequency and abundance, it can be concluded that Carassius gibelio can be considered a MP vector in fishmeal. The results provide an essential baseline for future MP studies on the potential effects of MPs on aquatic organisms, fate, and impact on the fishmeal production process, aquaculture practices, and human health.

Understanding the Impact of Biodegradable Microplastics on Living Organisms Entering the Food Chain: A Review

Microplastics (MPs) pollution has emerged as one of the world's most serious environmental issues, with harmful consequences for ecosystems and human health. One proposed solution to their accumulation in the environment is the replacement of nondegradable plastics with biodegradable ones. However, due to the lack of true biodegradability in some ecosystems, they also give rise to biodegradable microplastics (BioMPs) that negatively impact different ecosystems and living organisms. This review summarizes the current literature on the impact of BioMPs on some organisms-higher plants and fish-relevant to the food chain. Concerning the higher plants, the adverse effects of BioMPs on seed germination, plant biomass growth, penetration of nutrients through roots, oxidative stress, and changes in soil properties, all leading to reduced agricultural yield, have been critically discussed. Concerning fish, it emerged that BioMPs are more likely to be ingested than nonbiodegradable ones and accumulate in the animal's body, leading to impaired skeletal development, oxidative stress, and behavioral changes. Therefore, based on the reviewed pioneering literature, biodegradable plastics seem to be a new threat to environmental health rather than an effective solution to counteract MP pollution, even if serious knowledge gaps in this field highlight the need for additional rigorous investigations to understand the potential risks associated to BioMPs.

Detection of Various Microplastics in Patients Undergoing Cardiac Surgery

Microplastics have been detected in human stool, lungs, and placentas, which have direct exposure to the external environment through various body cavities, including the oral/anal cavity and uterine/vaginal cavity. Crucial data on microplastic exposure in completely enclosed human organs are still lacking. Herein, we used a laser direct infrared chemical imaging system and scanning electron microscopy to investigate whether microplastics exist in the human heart and its surrounding tissues. Microplastic specimens were collected from 15 cardiac surgery patients, including 6 pericardia, 6 epicardial adipose tissues, 11 pericardial adipose tissues, 3 myocardia, 5 left atrial appendages, and 7 pairs of pre- and postoperative venous blood samples. Microplastics were not universally present in all tissue samples, but nine types were found across five types of tissue with the largest measuring 469 μm in diameter. Nine types of microplastics were also detected in pre- and postoperative blood samples with a maximum diameter of 184 μm, and the type and diameter distribution of microplastics in the blood showed alterations following the surgical procedure. Moreover, the presence of poly(methyl methacrylate) in the left atrial appendage, epicardial adipose tissue, and pericardial adipose tissue cannot be attributed to accidental exposure during surgery, providing direct evidence of microplastics in patients undergoing cardiac surgery. Further research is needed to examine the impact of surgery on microplastic introduction and the potential effects of microplastics in internal organs on human health.

Monk seal faeces as a non-invasive technique to monitor the incidence of ingested microplastics and potential presence of plastic additives

Anthropogenic debris, including plastics, has recently been identified as a major threat for marine mammals and the Marine Strategy Framework Directive aims to achieve the good environmental status of European waters by addressing among other criteria, the effects of marine litter on biota. This study implemented for the first time a non-invasive technique for collecting monk seal samples to assess microdebris ingestion in combination with identifying plastic additives and porphyrins biomarkers. A total of 12 samples of monk seal faeces were collected from marine caves in Zakynthos Island, Greece. A total of 166 microplastic particles were identified; 75 % of the particles were smaller than 3 mm. Nine phthalates and three porphyrins were detected. A strong correlation was found between the number of microplastics and the concentration of phthalates. The values of both phthalates and porphyrins were found lower than in other marine mammal tissues, suggesting that seals might not be impacted by them yet.

Long term trends in floating plastic pollution within a marine protected area identifies threats for Endangered northern bottlenose whales

"The Gully", situated off Nova Scotia, Canada, is the largest submarine canyon in the western North Atlantic. This unique oceanographic feature, which became a Marine Protected Area (MPA) in 2004, is rich in marine biodiversity and is part of the critical habitat of Endangered northern bottlenose whales (Hyperoodon ampullatus). To understand the potential impact of plastic pollution in the MPA and on this Endangered cetacean, we evaluated trends over time in the abundance and composition of plastics and compared these to the stomach contents of recently stranded northern bottlenose whales. From the 1990s-2010s, the median abundance of micro-sized (<5 mm) and small plastics (5 mm-2.5 cm) increased significantly, while the median abundance of large plastics (>2.5 cm) decreased significantly. Plastic abundance from the 2010s for micro-sized and small plastics varied from 5586-438 196 particles km-2, higher than previously measured estimates for surrounding offshore areas. Polymers identified using FTIR spectroscopy included polyethylene, polypropylene, polyethylene terephthalate polyester, nylon, alkyds (paint), and natural and semi-synthetic cellulosic fibers. The abundance of large debris ranged from 0 to 108.6 items km-2 and consisted of plastic sheets and bags, food wrappers and containers, rope, fishing buoys, and small plastic fragments. Whale stomach contents contained fragments of fishing nets, ropes, bottle caps, cups, food wrappers, smaller plastic fragments, fibers, and paint flakes, consistent with the composition and character of items collected from their critical habitat. Despite being far from centres of human population, the unique oceanographic features of The Gully (i.e. currents and bathymetric complexity) may concentrate plastic debris, increasing exposure rates of whales to plastic pollution. The increase in micro-sized and small plastics over time suggests associated health and welfare impacts of ingested plastics should be accounted for in future recovery plans for this Endangered species.

Microplastic occurrence and phthalate ester levels in neuston samples and skin biopsies of filter-feeding megafauna from La Paz Bay (Mexico)

The impacts of microplastics on filter feeders megafauna have recently received increased attention. These organisms are potentially exposed to plastic ingestion and the release of added/sorbed contaminants during feeding activities. An assessment of microplastic abundance and the chemical impact of Phthalates esters (PAEs) were performed in neustonic samples and skin biopsies of Balaenoptera physalus and Rhincodon typus inhabiting the Gulf of California (Mexico). Sixty-eight percent of the net tows contained plastics with a maximum of 0.24 items/m³ mainly composed of polyethylene fragments. PAE levels were detected both in environmental and skin biopsy samples, with the highest values in the fin whale specimens (5291 ng/g d.w). Plasticizer fingerprint showed a similar distribution pattern between neustonic samples and filter-feeding species, with DEHP and MBP having the highest concentrations. The detection of PAE levels confirmed their potential role as plastic tracers and give preliminary information about the toxicological status of these species feeding in La Paz Bay.

Multiple endpoints of polyethylene microplastics toxicity in vascular plants of freshwater ecosystems: A study involving Salvinia auriculata (Salviniaceae)

More recently, the number of studies on the impacts of microplastics (MPs) on plants has drawn attention considerably. However, many of these studies focused on terrestrial plants, with vascular plants from freshwater ecosystems being little studied. Thus, we aimed to evaluate the possible effects of exposure of Salvinia auriculata, for 28 days, to different concentrations of polyethylene MPs (PE MPs - diameter: 35.46 ± 18.17 µm) (2.7 ×10⁸ and 8.1 ×10⁸ particles/m³), using different biomarkers. Our data indicated that exposure to PE MPs caused alterations in plant growth/development (inferred by the lower floating frond number, "root" length, and the number of "roots"), as well as lower dispersion of individuals in the experimental units. Plants exposed to PE MPs also showed lower epidermal thickness (abaxial leaf face) and a longer length of the central leaf vein and vascular bundle area. Ultrastructural analyses of S. auriculata exposed to MPs revealed rupture of some epidermal cells and trichomes on the adaxial and abaxial, leaf necrosis, and chlorosis. In the "roots", we observed dehydrated filamentous structures with evident deformations in plants exposed to the pollutants. Both on the abaxial leaf face and on the "roots", the adherence of PE MPs was observed. Furthermore, exposure to PE MPs induced lower chlorophyll content, cell membrane damage, and redox imbalance, marked by reduced catalase and superoxide dismutase activity and increased production of reactive oxygen and nitrogen species as well as malondialdehyde. However, in general, we did not observe the dose-response effect for the evaluated biomarkers. The values of the integrated biomarker response index, the principal component analysis (PCA) results and the hierarchical clustering analysis confirmed the similarity between the responses of plants exposed to different PE MPs concentrations. Therefore, our study sheds light on how PE MPs can affect S. auriculata and reinforces that putting these pollutants in freshwater environments might be hazardous from an ecotoxicological point of view.

Terrestrial mammals of the Americas and their interactions with plastic waste

Plastics have brought many benefits to society, but their mismanagement has turned them into a serious environmental problem. Today, the effects of plastic waste on wildlife are becoming increasingly evident. Since studies on plastic pollution have focused on species in marine ecosystems, here we review current knowledge on interactions between terrestrial mammals and plastic waste in the countries of the Americas, which is a global hotspot of mammalian biodiversity and in turn has, among its member countries, nations with high per capita generations of plastic waste globally. We identified 46 scientific articles documenting plastic ingestion in 37 species and four species that used plastic waste for nest or burrow construction. Of the 46 investigations, seven focused on plastic contamination, while the others reported on the presence of plastics in wildlife, even though this was not the primary focus of the research. However, these publications lack analytical methods commonly used in plastic studies, and only one study applied a standardized methodology for plastic detection. Therefore, in general, plastic pollution research on terrestrial mammals is limited. We extend several recommendations such as designing methodologies that are adapted to terrestrial mammals for the identification of plastics in fecal matter or gastrointestinal contents, carrying out species-specific analyzes on the impacts of plastics in nests or burrows, and giving further attention to this understudied issue and taxa.

Organic Pollutants Associated with Plastic Debris in Marine Environment: A Systematic Review of Analytical Methods, Occurrence, and Characteristics

Plastic pollution has become one of the most serious environmental problems, and microplastics (MPs, particles < 5 mm size) may behave as a vehicle of organic pollutants, causing detrimental effects to the environment. Studies on MP-sorbed organic pollutants lack methodological standardization, resulting in a low comparability and replicability. In this work, we reviewed 40 field studies of MP-sorbed organic contaminants using PRISMA guidelines for acquiring information on sampling and analytical protocols. The papers were also scored for their reliability on the basis of 7 criteria, from 0 (minimum) to 21 (maximum). Our results showed a great heterogeneity of the methods used for the sample collection, MPs extraction, and instruments for chemicals' identification. Measures for cross-contamination control during MPs analysis were strictly applied only in 13% of the studies, indicating a need for quality control in MPs-related research. The most frequently detected MP-sorbed chemicals were polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). Most of the studies showed a good reliability (>75% of the total score), with 32 papers scoring 16 or higher. On the basis of the collected information, a standardizable protocol for the detection of MPs and MP-sorbed chemicals has been suggested for improving the reliability of MPs monitoring studies.

No accumulation of microplastics detected in western Canadian ringed seals (Pusa hispida)

Ringed seals (Pusa hispida) play a crucial role in Arctic food webs as important pelagic predators and represent an essential component of Inuvialuit culture and food security. Plastic pollution is recognized as a global threat of concern, and Arctic regions may act as sinks for anthropogenic debris. To date, mixed evidence exists concerning the propensity for Canadian Arctic marine mammals to ingest and retain plastic. Our study builds on existing literature by offering the first assessment of plastic ingestion in ringed seals harvested in the western Canadian Arctic. We detected no evidence of microplastic (particles ≥80 μm) retention in the stomachs of ten ringed seals from the Inuvialuit Settlement Region (ISR) in the Northwest Territories, Canada. These results are consistent with previous studies that have found that some marine mammals do not accumulate microplastics in evaluated regions.

Biological effects on the migration and transformation of microplastics in the marine environment

Microplastics(MPs) are ubiquitous, difficult to degrade, and potentially threatening to organisms in marine environment, so it is important to clarify the factors that affect their biogeochemical processes. The impact of biological activities on the MPs in marine environment is ubiquitous and complex, and there is currently a lack of systematic summaries. This paper reviews the effects of biological actions on the migration, distribution and degradation of MPs in marine environment from four aspects: biological ingestion and digestion, biological movement, biological colonization and biological adhesion. MPs in seawater and sediments can be closely combined with organisms through three pathways: biological ingestion, biofilm formation or adhesion to organisms, and are passed between species at different trophic levels through the food chain. The generation and degradation of faecal pellets and biofilms can alter the density of "environmental MPs", thereby affecting their vertical migration and deposition in water bodies. The movement of swimming organisms and the disturbance by benthic organisms can promote the migration of MPs in water and vertical migration and resuspension in sediments, thereby changing the distribution of MPs in local sea areas. The grinding effect of the digestive tract and the secretion of chemicals from the biofilm (such as enzymes and acids) can reduce the particle size and increase surface roughness of MPs, or even degrade them completely. Besides, biological adhesion may be an important mechanism affecting the distribution, migration and preservation of MPs. There may be complex interactions and linkages among marine dynamical processes, photochemical degradation and biological processes that collectively affect the biogeochemical processes of MPs, but their relative contributions remain to be more studied.

Screening for Influenza and Morbillivirus in Seals and Porpoises in the Baltic and North Sea

Historically, the seals and harbour porpoises of the Baltic Sea and North Sea have been subjected to hunting, chemical pollutants and repeated mass mortalities, leading to significant population fluctuations. Despite the conservation implications and the zoonotic potential associated with viral disease outbreaks in wildlife, limited information is available on the circulation of viral pathogens in Baltic Sea seals and harbour porpoises. Here, we investigated the presence of the influenza A virus (IAV), the phocine distemper virus (PDV) and the cetacean morbillivirus (CeMV) in tracheal swabs and lung tissue samples from 99 harbour seals, 126 grey seals, 73 ringed seals and 78 harbour porpoises collected in the Baltic Sea and North Sea between 2002–2019. Despite screening 376 marine mammals collected over nearly two decades, we only detected one case of PDV and two cases of IAV linked to the documented viral outbreaks in seals in 2002 and 2014, respectively. Although we find no evidence of PDV and IAV during intermediate years, reports of isolated cases of PDV in North Sea harbour seals and IAV (H5N8) in Baltic and North Sea grey seals suggest introductions of those pathogens within the sampling period. Thus, to aid future monitoring efforts we highlight the need for a standardized and continuous sample collection of swabs, tissue and blood samples across Baltic Sea countries.

Beyond the exposure phase: Microplastic depuration and experimental implications

Currently, most studies focus on the effect of microplastics (MPs) in the exposure phase, but pay limited attention to the depuration phase. Depuration is a promising practice to achieve safe aquaculture production, which is also helpful to understand the long-term impact of MPs. Therefore, investigating the post-exposure scenarios of MPs has great practical significance. In order to provide implications for future research, this work attempted to systematize the current findings and knowledge gaps regarding the depuration of MPs. More specifically, three methods, including direct fitting, one-compartment kinetic model and interval observation, for estimating the retention time of MPs to further determine the minimum depuration time were introduced, in which the one-compartment kinetic model could also be used to calculate the depuration rate constant and biological half-life of MPs. Moreover, the post-exposure effect of MPs generally presented three scenarios: incomplete reversal (legacy effect), return to control level (recovery) and stimulatory response (hormesis-like effect). In addition, the possible tissue translocation of MPs, the influence of food abundance and body shape on MPs egestion, and the potential interaction with environmental factors, have aroused great scientific concerns and need further exploration and clarification.

The Role of Bacterial Polyhydroalkanoate (PHA) in a Sustainable Future: A Review on the Biological Diversity

Environmental challenges related to the mismanagement of plastic waste became even more evident during the COVID-19 pandemic. The need for new solutions regarding the use of plastics came to the forefront again. Polyhydroxyalkanoates (PHA) have demonstrated their ability to replace conventional plastics, especially in packaging. Its biodegradability and biocompatibility makes this material a sustainable solution. The cost of PHA production and some weak physical properties compared to synthetic polymers remain as the main barriers to its implementation in the industry. The scientific community has been trying to solve these disadvantages associated with PHA. This review seeks to frame the role of PHA and bioplastics as substitutes for conventional plastics for a more sustainable future. It is focused on the bacterial production of PHA, highlighting the current limitations of the production process and, consequently, its implementation in the industry, as well as reviewing the alternatives to turn the production of bioplastics into a sustainable and circular economy.

Pro-Inflammatory and Cytotoxic Effects of Polystyrene Microplastics on Human and Murine Intestinal Cell Lines

Plastic is a polymer extremely resistant to degradation that can remain for up to hundreds or thousands of years, leading to the accumulation of massive amounts of plastic waste throughout the planet's ecosystems. Due to exposure to various environmental factors, plastic breaks down into smaller particles named microplastics (1-5000 μm) and nanoplastics (<1 μm). Microplastics (MPs) are ubiquitous pollutants but, still, little is known about their effects on human and animal health. Herein, our aim is to investigate cytotoxicity, oxidative stress, inflammation and correlated gene modulation following exposure to polystyrene microplastics (PS-MPs) in HRT-18 and CMT-93 epithelial cell lines. After 6, 24 and 48 h PS-MPs treatment, cell viability (MTT) and oxidative stress (SOD) assays were performed; subsequently, expression changes and cytokines release were investigated by Real-Time PCR and Magnetic-beads panel Multiplex Assay, respectively. For each exposure time, a significantly increased cytotoxicity was observed in both cell lines, whereas SOD activity increased only in CMT-93 cells. Furthermore, Magnetic-beads Multiplex Assay revealed an increased release of IL-8 in HRT-18 cells' medium, also confirmed by gene expression analysis. Results obtained suggest the presence of a pro-inflammatory pattern induced by PS-MPs treatment that could be related to the observed increase in cytotoxicity.

Detection of microplastic particles in scats from different colonies of California sea lions (Zalophus californianus) in the Gulf of California, Mexico: A preliminary study

Microplastics (MPs, < 5 mm in size) are highly bioavailable to many taxa within the marine ecosystem, either ingested directly or indirectly through trophic transfer from polluted prey. The ingestion analysis of these MPs from top predators, such as pinnipeds in Mexico, is relatively unexplored. Forty-eight scats from California sea lions were collected on six rookeries along the Gulf of California. From these scat samples, 294 suspected MPs particles were classified and chemically analyzed; 34% were synthetic and semi-synthetic, and 66% were non-synthetic. Blue-colored polyethylene terephthalate fibers were the most common type of MP registered. During laboratory work, multiple contamination control measures were implemented. Although the ingestion pathway is still unknown, our results support the other authors that suggest the potential trophic transfer of MPs to top predators and incidental ingestion while foraging. The particles documented here provide important baseline information for future MP research in the Gulf of California.

Is Wild Marine Biota Affected by Microplastics?

The present review provides detailed information on the adverse effects of MPs on wild marine organisms, including tissue damage, fish condition, oxidative stress, immune toxicity, and genotoxicity. A bibliometric analysis was carried out on CiteSpace (version 6.1.R3) (Drexel University, Philadelphia, PA, USA) to verify how many papers studied the effects on wild marine species. The results showed a total of 395 articles, but only 22 really presented data on the effects or impacts on marine biota, and of these, only 12 articles highlighted negative effects. This review shows that the observed effects in wild organisms were less severe and milder than those found in the experimental conditions. The knowledge of negative effects caused by direct ingestion of microplastics in wild animals is still limited; more efforts are necessary to fully understand the role of MPs and the adverse effects on wild marine organisms, the ecosystem, and human health.

First Assessment of Micro-Litter Ingested by Dolphins, Sea Turtles and Monk Seals Found Stranded along the Coasts of Samos Island, Greece

This study is the first to assess the occurrence of micro-litter ingested by marine megafauna in the north-eastern Aegean Sea. A total of 25 specimens from four species of marine mammals, including dolphins and monk seals, and two species of sea turtles, found stranded along the coastline of Samos Island, Greece, were selected for the analysis. Litter particles, identified as microplastics (MPs), were ubiquitous throughout all sections of the gastrointestinal tract (oesophagus, stomach and intestine) in all specimens. Overall, the MPs most frequently found were black fibres 0.21-0.50 mm in size. These results provide insight into the extent of micro-litter ingestion and contamination in marine vertebrates. Here we propose a method of standardisation to establish a baseline for marine taxa in this region of the Mediterranean Sea, where knowledge of the topic is still lacking.

Characterisation of plasmatic B-esterases in bottlenose dolphins (Tursiops truncatus) and their potential as biomarkers of xenobiotic chemical exposures

A total of 164 blood samples from 16 clinically healthy bottlenose dolphins (Tursiops truncatus), were obtained from an aquarium in Spain between 2019 and 2020, as part of their preventive medicine protocol. In addition to conventional haematological and biochemical analyses, plasmatic B-esterase activities were characterised to determine the potential application of such analyses in wild counterparts. The hydrolysis rates for the substrates of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and carboxylesterase (CE) activity in plasma were measured, the last using two commercial substrates, p-nitrophenyl acetate (pNPA) and p-nitrophenyl butyrate (pNPB). Activity rates (mean ± SEM in nmol/min/mL plasma) were (in descending order): AChE (125.6 ± 3.8), pNPB-CE (65.0 ± 2.2), pNPA-CE (49.7 ± 1.1) and BuChE (12.8 ± 1.3). These values for dolphins are reported in here for the first time in this species. Additionally, the in vitro sensitivity of two B-esterases (AChE and pNPB-CE) to chemicals of environmental concern was determined, and the protective role of plasmatic albumin assessed. Out of the B-esterases measured in plasma of dolphin, AChE activity was more responsive in vitro to pesticides, while CEs had a low response to plastic additives, likely due to the protective presence of albumin. However, the clear in vitro interaction of these environmental chemicals with purified AChE from electric eels and recombinant human hCEs (hCE1 and hCE2) and albumin, predicts their impact in other tissues that require in vivo validation. A relationship between esterase-like activities and health parameters in terrestrial mammals has already been established. Thus, B-esterase measures could be easily included in marine mammal health assessment protocols for dolphins as well, once the relationship between these measures and the animal's fitness has been established.