Microplastic and tar pollution on three Canary Islands beaches: An annual study

Assessment of seabed litter at Concepción Seamount (Canary island) using a remotely operated towed vehicle

The seafloor is recognised as a major sink for marine litter. However, studies conducted in this compartment addressing marine litter densities and its interactions with fauna are scarce, mainly due to sampling constraints. In this paper, we assess marine litter density, composition and interactions with marine communities and evaluate its relationship with fishing activities at the "Banco de la Concepción" seamount (Canary Islands, Spain). We took advantage of underwater video records taken with a Remotely Operated Towed Vehicle in the framework of the LIFE IP INTEMARES project. A total of 56 video transects were analysed covering about 9 km with 19 h of video recording. Transects were categorised as high, low, and null fishing effort based on the Vessel Monitoring System (VMS) positional data registered between 2009 and 2017. Litter items were recorded in 70% of the transects with a mean density of 2122 (±2464) items km-2. There were significant differences in litter densities over the three levels of fishing pressure, with a density decrease from stations of high to stations of null fishing pressure. Regarding categories, plastic was by far the most abundant category found (83.1%), mainly consisting of fishing lines, both monofilaments and entangled longlines. The study of the interactions of marine litter with fauna showed that less than 20% of the items presented an interaction with benthic organisms either by causing or not a visible impact. The sponge Asconema setubalense accounted for more than half (57.4%) of all interactions, but only 5% of all A. setubalense specimens showed physical damage.

Microplastic and mesoplastic pollution in surface waters and beaches of the Canary Islands: A review

The Canary Archipelago is a group of volcanic islands located in the North Atlantic Ocean with high marine biodiversity. This archipelago intercepts the Canary Current, the easternmost branch of the Azores Current in the North Atlantic Subtropical Gyre, which brings large amounts of litter from remote sources via oceanic transportation. It is, therefore, particularly vulnerable to marine plastic pollution. Here, we present a review of the available studies on mesoplastics and microplastics in the Canary Islands over the last decade to evaluate the level and distribution of plastic pollution in this archipelago. Specifically, we focused on data from beaches and surface waters to assess the pollution level among the different islands as well as between windward and leeward zones, and the main characteristics (size, type, colour, and polymer) of the plastics found in the Canary Islands. The concentrations of meso- and MPs on beaches ranged from 1.5 to 2972 items/m2 with a mean of 381 ± 721 items/m2. The concentration of MPs (>200 μm) in surface waters was highly variable with mean values of 998 × 103 ± 3364 × 103 items/km2 and 10 ± 31 items/m3. Plastic pollution in windward beaches was one order of magnitude significantly higher than in leeward beaches. The accumulation of MPs in surface waters was higher in the leeward zones of the high-elevation islands, corresponding to the Special Areas of Conservation (ZECs) and where the presence of marine litter windrows (MLW) has been reported. Microplastic fragments of polyethylene of the colour category "white/clear/uncoloured" were the most common type of plastic reported in both beaches and surface waters. More studies on the occurrence of MLW in ZECS and plastic pollution in the water column and sediments, including small-size fractions (<200 μm), are needed to better assess the level of plastic pollution and its fate in the Canary Islands. Overall, this review confirms that the Canary Archipelago is a hotspot of oceanic plastic pollution, with concentrations of MPs in surface waters in the highest range reported for oceanic islands and one of the highest recorded mean concentrations of beached meso- and microplastics in the world.

Lost and found: Patterns of marine litter accumulation on the remote Island of Santa Luzia, Cabo Verde

Santa Luzia, an uninhabited island in the archipelago of Cabo Verde, serves as a natural laboratory and important nesting site for loggerhead turtles Carettacaretta. The island constitutes an Integral Natural Reserve and a Marine Protected Area. We assessed marine litter accumulation on sandy beaches of the island and analysed their spatial patterns using two sampling methods: at a fine scale, sand samples from 1 × 1 m squares were collected, identifying debris larger than 1 mm; at a coarse scale, drone surveys were conducted to identify visible marine debris (>25 mm) in aerial images. We sampled six points on three beaches of the island: Achados (three points), Francisca (two points) and Palmo Tostão (one point). Then, we modelled the abundance of marine debris using topographical variables as explanatory factors, derived from digital surface models (DSM). Our findings reveal that the island is a significant repository for marine litter (>84% composed of plastics), with up to 917 plastic items per m2 in the sand samples and a maximum of 38 macro-debris items per m2 in the drone surveys. Plastic fragments dominate, followed by plastic pellets (at the fine-scale approach) and fishing materials (at the coarse-scale approach). We observed that north-facing, higher-elevation beaches accumulate more large marine litter, while slope and elevation affect their spatial distribution within the beach. Achados Beach faces severe marine debris pollution challenges, and the upcoming climate changes could exacerbate this problem.

Assessment of microplastic abundance and impact on recreational beaches along the western Algerian coastline

Microplastics (MPs) have attracted global attention due to their ubiquity and potential impact on the environment. However, MPs are poorly documented along the Algerian coast. To address this data gap, this study investigated the presence of MPs on three recreational beaches in western Algeria (Stidia, Sablettes and Mersat El Hadjaj). The mean MP abundance for the three beaches was estimated at 55.47 ± 48.01 items/m2. Characterization of MPs shape revealed that fragments (79.81 %) were dominant, followed by pellets (10.58 %), filaments (5.57 %), and foam (3.85 %). An assessment of the Microplastic Pollution Index, the Pellet Pollution Index, and the Coefficient of Microplastic Impact, revealed the presence of very low to moderate levels of MPs on the beaches. This presence was associated with minimal beach pollution and moderate overall impact. The sector analysis approach results confirm that there are two different magnitudes of MPs presence that can negatively impact on the environmental quality of the studied beaches.

Beadlet anemone: A novel bio-indicator of microplastic pollution in the marine environment

Extensive usage of plastic in different industries and household usage has degraded to microplastic due to environmental conditions over the last year. While several researchers conducted the determination of microplastic (MP) bioaccumulation from rivers to stormwater, except for some filter-feeding species used as a bioindicator, to achieve a holistic approach to the fate of MPs in the marine system, sea anemone was used as an indicator. Microplastics were extracted from surface seawater, sediment, and sea anemones from the same sampling area and characterized. The extracted MPs were confirmed by confocal micro-Raman spectroscopy, and the morphology of the MPs was investigated by scanning electron microscopy (SEM). The results showed that the accumulation of microplastics and the type of polymer, shape, colour, and size of these persistent pollutants varied in sediment, surface water, and sea anemone. The abundance of MPs was different, and grey-coloured MPs were detected at a relatively higher level in sea anemones, from 8.7 to 13.3%, and more minor MPs (less than 0.5 mm) at 43.4-56.8% were detected in sea anemones among the sampling stations. In terms of polymer type, there are relatively more types of polymers classified in sea anemones among the sampling stations (six different types of polymers). These results indicated that the utilization of sea anemones as a bioindicator for MPs could be a critical factor in a better understanding of their pathway in the marine ecosystem. This study proved that analysing sea anemones as an indicator could offer a reliable, fast, and time-saving approach for detecting microplastic accumulation in marine systems.

Three-dimensional evaluation of beaches of oceanic islands as reservoirs of plastic particles in the open ocean

The quantification of plastic debris on beaches has been extensively used as an indicator of plastic pollution in the marine environment. However, most efforts have focused on surface layers, with few investigations looking deeper into the substrate, thus underestimating total standing stocks. Such information is crucial to improve our understanding of where plastic accumulates in the oceans. In this study, we investigated the three-dimensional distribution of plastic (>1 mm) in three sandy beaches located in oceanic islands of the North Atlantic (Azores and the Canary Islands) that are known to accumulate significant quantities of small plastic debris at the surface layer. On each beach, we collected a total of 16 sediment cores down to 1 m depth, from the high tide line up to the backshore following a stratified random sampling design spread across four different levels across the beach. Samples were taken every 10 cm down to 1 m into the sand. Our results revealed the presence of plastic items in the deepest layers with subsurface layers accounting for 84 % of the total plastic abundance and with a similar pattern in terms of size, shape, colour and composition. Furthermore, we found increasing plastic concentrations towards the upper levels of the beach, indicating longer term accumulation in the backshore. Collectively, this study suggests that the plastic items reaching sandy beaches of the Macaronesia are being incorporated into its deepest layers, acting as reservoirs of plastic in the open ocean.

Anthropogenic debris ingestion in a tropical seabird community: Insights from taxonomy and foraging distribution

Oceans have been considered as an unlimited supply of goods and services, but resource extraction and waste disposal became ubiquitous and have been damaging the health of marine ecosystems. Finding suitable sentinel species of the human impacts on the oceans is thus imperative, since they may work as early warnings of disruptive situations. In this study, we investigated how taxonomy and foraging distribution influenced the occurrence of anthropogenic debris among five seabird species inhabiting the tropical Atlantic region. Occurrence of anthropogenic debris was assessed using faeces of breeding individuals as a proxy of ingestion. A total of 268 particles were extracted from all samples. The categories "fragments" and "fibres", as well as the colour "blue", were the most prevalent characteristics across species. There was a high diversity of polymers from cellulosic particles to synthetic plastics (Anthropogenic Cellulosic 26.9 %; Polyester 7.7 %; Varnish 5.8 %; Polypropylene 1.9 %). Species with a more coastal foraging strategy exhibited higher occurrence and number of anthropogenic debris when compared to species foraging comparably more in pelagic areas. This suggests that anthropogenic debris are more prevalent in coastal foraging areas, where human activities occur in higher number and frequency (e.g., fisheries) and sources of freshwater input from inland are at close distance. These results provide more evidence to the growing perception on the ubiquity and diversity of anthropogenic debris in the marine environment, and further support the usefulness of using seabirds as bio-indicators of anthropogenic pollution in both neritic and oceanic regions.

Searching for hotspots of neustonic microplastics in the Canary Islands

In this study, we investigated the concentration, distribution, and characteristics of neustonic MPs in the Canary Islands, with a particular focus on the island leeward zones, where a high accumulation of floating marine microplastics is expected. Samples were collected with a manta net at 15 different sites from Alegranza to La Gomera during the IMPLAMAC expedition. The microplastic concentration in surface waters ranged from 0.27 MPs/m³ in Alegranza to 136.7 MPs/m³ in the south of Gran Canaria. The highest concentration of MPs found was due to the presence of a sea-surface slick, also called "marine litter windrow", formed in the south of Gran Canaria. The most abundant zooplankton group in the neuston was copepods, except at the marine litter windrow where fish larvae and eggs predominated. This indicates that coastal areas where marine litter windrows are formed have a high risk of MP ingestion and potential adverse effects on biota.

Bacterial Colonization of Microplastics at the Beaches of an Oceanic Island, Tenerife, Canary Islands

(1) Isolated systems, such as oceanic islands, are increasingly experiencing important problems related to microplastic debris on their beaches. The formation of microbial biofilm on the surface of microplastics present in marine environments provides potential facilities for microorganisms to survive under the biofilm. Moreover, microplastics act as a vehicle for the dispersion of pathogenic organisms, constituting a new route of exposure for humans. (2) In this study, the microbial content (FIO and Vibrio spp. and Staphylococcus aureus) of microplastics (fragments and pellets) collected from seven beaches of the oceanic island of Tenerife, in the Canary Islands (Spain), was determined. (3) Results showed that Escherichia coli was present in 57.1% of the fragments and 28.5% of the pellets studied. In the case of intestinal Enterococci, 85.7% of the fragments and 57.1% of the pellets tested positive for this parameter. Finally, 100% of the fragments and 42.8% of the pellets analyzed from the different beaches contained Vibrio spp. (4) This study shows that microplastics act as reservoirs of microorganisms that can increase the presence of bacteria indicating faecal and pathogenic contamination in bathing areas.

Assessment on the pollution level and risk of microplastics on bathing beaches: a case study of Liandao, China

Microplastic pollution on bathing beaches threatens the health of human beings and coastal organisms. There is a lack of assessment on the level of microplastic pollution and the health risk associated with plastics. As one of the earliest open bathing beaches in China, Liandao is well known as the two high-quality beaches. However, little is known about the extent of microplastic pollution on these bathing beaches. Based on the analysis of microplastic pollution abundance, distribution, shape, size, color, and composition at the Liandao bathing beaches, this study puts forward a novel approach to comprehensively evaluate the microplastic pollution level and risk level by using the Nemerow pollution index (NPI) and polymer hazard index (PHI). The results show that the average abundance of microplastics on the Liandao bathing beaches is 135.42 ± 49.58 items/kg; the main shapes are fibers, fragments, and granules. Most of the microplastics are transparent, brown, and black, accounting for 71.54%, and they have an average particle size of 0.63 ± 0.43 mm. The main components are PE, PP, PS, PET, and nylon, of which nylon appears in the highest proportion (54.77%). The microplastic NPI and PHI values are 0.38 and 74.81, respectively, indicating that the pollution level and health risk index of microplastics on the Liandao bathing beaches are both low. With the increase in population and per capita consumption, plastic waste generated on land will continue to increase. Finally, this study puts forward some suggestions regarding microplastic monitoring, plastic waste management, and environmental attitudes and behavior.

Microplastics ingestion and chemical pollutants in seabirds of Gran Canaria (Canary Islands, Spain)

Plastic pollution constitutes an environmental problem in the Canary Islands nowadays. Nevertheless, studies evaluating the impact of plastics on its avifauna are still scarce. Gastrointestinal tracts of 88 birds belonging to 14 species were studied for the presence of plastics. Moreover, their livers were analyzed for the determination of bromodiphenyl ethers (BDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). Among Cory's shearwaters (n = 45), the frequency of occurrence of plastic ingestion was considerably high (88.89 %). This species had the highest mean value of items (7.22 ± 5.66) and most of them were compatible with lines derived from fishing gear. PCBs and PAHs were detected in all of the samples and OCPs in the great majority of them (98.86 %). Our results highlight the problems that plastic debris (mainly for seabirds) and organic pollutants pose to these species.

Abundance, composition and sources of beach litter on the Cape Verdean island São Vicente

This study represents the first assessment of beach litter on an island of the west African archipelagic state of Cape Verde. On five beaches of São Vicente, litter was collected along transects and classified according to the OSPAR protocol, with the Matrix Scoring Technique used to allocate it to four sources. Beach litter on São Vicente is highly variable in both amount and composition, while land- and sea-based sources contribute to litter loads to different extents depending on the use and geographic orientation of the beach. Four of the five surveyed beaches exhibited litter loads that were similar to pollution levels previously described for other oceanic islands, while a north-eastern-facing beach featured exceptionally high loads. This was presumably because it receives litter from distant sources due to its exposure to a major ocean surface current.

Synthetic microplastic abundance and composition along a longitudinal gradient traversing the subtropical gyre in the North Atlantic Ocean

Plastic pollution has been reported in the North Atlantic Ocean since the 1970s, yet limited data over subsequent decades pose challenges when assessing spatio-temporal trends in relation to global leakages and intervention strategies. This study quantified microplastics within the upper ocean along a longitudinal transect of the North Atlantic and its subtropical gyre. Microplastics were sampled from surface and subsurface (-25 m) water using a manta trawl and NIKSIN bottle respectively. The surface water polymer community varied significantly between geographic positions ('inshore', 'gyre', 'open ocean'), and was significantly influenced by fragment quantity. Compared to other positions, the North Atlantic gyre was associated with high concentrations of polyethylene, polypropylene, acrylic and polyamide fragments. Subsurface water was dominated by polyamide and polyester fibres. Backtracked 2-year Lagrangian simulations illustrated connectivity patterns. Continued monitoring of microplastics throughout the water column of the North Atlantic Ocean is required to address knowledge gaps and assess spatio-temporal trends.

Occurrence, distribution, and associated pollutants of plastic pellets (nurdles) in coastal areas of South Texas

Nurdles, also known as plastic resin pellets, are now a major source of plastic pollution on beaches globally, thus it is important to elucidate their weathering patterns and environmental fates as well as the associated pollutants. In this study we collected nurdles from 24 sites in the coastal bend region of south Texas, covering areas from the near shore railway stations to the adjacent bays and barrier islands. The morphologies of nurdles and associated pollutants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and mercury, were investigated. The results showed that the nurdles varied greatly in color, shape, polymer composition, and oxidation degree. More than 80 % of the nurdles were made with polyethylene, and the rest with polypropylene, polyester, polystyrene, polyethylene-vinyl acetate, and polyvinyl chloride based on Fourier Transform Infrared Spectroscopy (FTIR) analysis. PCBs were not detected on nurdles. PAHs and mercury on nurdles were detected at 12 % and 20 % of the sampling sites. The total concentrations of detectable PAHs ranged from 92.59 to 1787.23 ng/g-nurdle, and the detectable mercury concentrations ranged from 1.23 to 22.25 ng/g-nurdle. Although the concentrations of these pollutants were not at the acute toxic effect level, the presence of PAHs and mercury suggested the potential risk of pollutant exposure to marine organisms in ecosystems, given the fact that nurdles are persistent in the environment.

Plastitar: A new threat for coastal environments

Oil residues have been frequently found on the coasts all over the world as a result of different accidental releases. Their partial evaporation and solidification onto the coastal rocks can produce the formation of a new solid structure forming an agglomerate with other materials, mainly microplastics (though wood, glass, sand and rocks were also found), yielding to a new plastic formation, name herein for the first time as "plastitar". These new formations have been found in several of the islands of the Canary Islands archipelago (Spain). Their study has shown that these new formations can be permanently attached to the rock, occupying even a 56% of the sampled area with an heterogeneous distribution. It was also observed that the studied plastitar was composed mainly of tar and polyethylene (90.6% of the studied particles) and polypropylene (9.4% of the studied particles) microplastics, primarily fragments (82.5%), pellets (15.7%) and lines (1.8%). The ever more frequent presence of plastics and, in particular, microplastics in coastal environments can lead to the common occurrence of these new plastic formations (probably present in other parts of the world), which long-term effects on the coasts should be further investigated.

Stranded pellets in Fildes Peninsula (King George Island, Antarctica): New evidence of Southern Ocean connectivity

Plastic and microplastic debris is transported by ocean currents over long distances, reaching remote areas, far from its original source. In Polar Regions, microplastics (MPs) can come from local activities or be transported from lower latitudes, with the former being the likely and major source. Although historically Antarctica was considered isolated from the global ocean, there is recent evidence of materials and organisms being transported in and out of the Southern Ocean, despite its multi-front structure. During the austral summer of 2019, beach surveys were conducted on the NW coast of the Fildes Peninsula (King George Island). The beach was characterised, and the first 2 cm of sediment from 5 quadrants (50 × 50 cm) along 100 m of the highest strandline were collected. Large microplastics (LMPs) and mesoplastics (MesoPs) were isolated, counted, measured, weighed and classified by shape. Polymer composition was analysed by FTIR and ageing estimated by Carbonyl Index. We found 293 items of LMPs (188 items) and MesoPs (105 items), with a total average density (±SD) of 234.4 ± 166 items m^-2. Foams (130.4 ± 76.3), fragments (58.4 ± 56.0) and pellets (44.0 ± 50.5) were the most abundant shapes. The main polymers found were polystyrene, polypropylene, and polyethylene. We found pellets among the MesoPs, being the first record for beaches in Antarctica. The presence of these primary MPs south of 62°S not only alerts about their possible direct consequences on Antarctic ecosystems, but also gives empirical evidence for the passive entry of plastic debris from lower latitudes through cross-frontal exchanges, providing new evidence of a global connectivity of the Southern Ocean. Despite increasing research, knowledge of plastics dynamics and their impact in the Southern Ocean and Antarctica is still limited but certainly necessary.

First evidence of plastic pollution in beach sediments of the Skikda coast (northeast of Algeria)

This study is the first attempt to provide original data on plastics debris occurrence in beach sediments of the Gulf of Skikda in Algeria (southwestern Mediterranean). Sediment samples from seven beaches were collected to extract, quantify and characterize mesoplastics and microplastics. Particles were classified by size into mesoplastics (5-25 mm) and large microplastics (1-5 mm). Overall, microplastics were the most abundant size fraction in terms of number of items. The average mass of mesoplastics was twice that of microplastics, revealing a notable reservoir of plastics that is scarcely ever reported in the literature. The predominant types were fragments and pellets, white/transparent in color. The average concentrations of total plastic were 1067.19 ± 625.62 items/m², 106.98 ± 62.39 items/kg, and 50.65 ± 9.82 g/m², showing variability between beaches and within sampling sites. Thus, the Skikda coast has high levels of pollution compared to other areas of the Mediterranean Sea.

Bioaccumulation of additives and chemical contaminants from environmental microplastics in European seabass (Dicentrarchus labrax)

Marine microplastic pollution is one of the biggest environmental problems we face. The growth of plastic production has not ceased since the 1950s and it is currently estimated that 368 tons of plastic were produced in 2019 (PlascticsEurope, 2020). Geyer et al. (2017) estimate that 79% of the plastic produced in the world still remains in the environment; this plastic due to the effect of degradation and subsequent fragmentation, is present in the form of microplastics in all oceans and, due to its small size can be ingested by fish and filter-feeding organisms. In addition, microplastics have additives and chemical contaminants associated with them, and the potential effect of microplastic ingestion on marine organisms, and through them, the potential risk to humans, is unknown. In the present study, European seabass (Dicentrarchus labrax) were fed for 60 days with three treatments: Control (feed), MP (feed with 10% virgin microplastics) and EMP (feed with 10% environmental microplastics), being the first study to evaluate long-term accumulation of contaminants due to ingestion of environmental microplastics (EMP) in fish. Both plastic additives such as PBDEs, and chemical contaminants adsorbed from the environment such as PCBs and DDE, were analyzed in the EMP, feed and liver. The concentration of microplastics in the feed was calculated based on the MPs/zooplankton wet weight (WW) ratio of 0.1 found in an area of maximum accumulation in the Canary Islands. Therefore, it is an experiment that simulates real conditions, but in the worst-case scenario, using both, concentrations based on data obtained in oceanographic campaigns and microplastics collected from the environment. Our results show that in this scenario, additives and chemical contaminants adsorbed on EMPs bioaccumulate in fish liver due to long-term ingestion of microplastics.

First inventory of marine debris on Alegranza, an uninhabited island in the Northeast Atlantic

Alegranza is the most northerly island of the Canary Islands archipelago, the first obstacle crossed by the Canary Current. From July to October 2020, six expeditions were led to the island to make a first inventory of marine debris and its possible source and origin. In total, 3667 objects weighing 321 kg were removed, excluding wooden objects. Of these, 97.7% were plastics, the most abundant being drink bottles (25.4%). While knowing the origin, source and pathway of debris is difficult, legible labels provided valuable information. In Alegranza, 66.7% of the legible bottle labels indicated Asian countries of manufacture, which is evidence that the source is maritime traffic in the region. The lobster trap license labels from the east coast of the United States and Canada were dated from 1999 to 2018, supporting both the exogenous origin and long lifetime in the ocean of these debris.

Microplastic-associated pathogens and antimicrobial resistance in environment

The ubiquitous use of microplastics and their release into the environment especially the water bodies by anthropogenic/industrial activities are the major resources for microplastic contamination. The widespread and often injudicious use of antimicrobial drugs or antibiotics in various sectors including human health and hygiene, agriculture, animal husbandry and food industries are leading to the release of antibiotics into the wastewater/sewage and other water bodies, particularly in urban setups and thus leads to the antimicrobial resistance (AMR) in the microbes. Microplastics are emerging as the hubs as well as effective carriers of these microbial pathogens beside their AMR-genes (ARGs) in marine, freshwater, sewage/wastewater, and urban river ecosystems. These drug resistant bacteria interact with microplastics forming synthetic plastispheres, the ideal niche for biofilm formations which in turn facilitates the transfer of ARGs via horizontal gene transfer and further escalates the occurrence and levels of AMR. Microplastic-associated AMR is an emerging threat for human health and healthcare besides being a challenge for the research community for effective management/address of this menace. In this review, we encompass the increasing prevalence of microplastics in environment, emphasizing mainly on water environments, how they act as centers and vectors of microbial pathogens with their associated bacterial assemblage compositions and ultimately lead to AMR. It further discusses the mechanistic insights on how microplastics act as hosts of biofilms (creating the plastisphere). We have also presented the modern toolbox used for microplastic-biofilm analyses. A review on potential strategies for addressing microplastic-associated AMR is given with recent success stories, challenges and future prospects.

Microplastic pollution in sublittoral coastal sediments of a North Atlantic island: The case of La Palma (Canary Islands, Spain)

In this work, the microplastic content of sediments collected in July 2020 between 5 and 7 m depth was studied in four locations of La Palma island (Canary Islands, Spain). At each sampling location, three samples were taken parallel to the shoreline. The microplastic content in each sampling corer was studied every 2.5 cm depth after digestion with a H₂O₂ solution followed by flotation in a saturated NaCl solution. Visualization of the final filtrates under a stereomicroscope revealed that all the sediment samples evaluated contained mostly microfibers (98.3%) which were mainly white/colorless (86.0%) and blue (9.8%), with an average length of 2423 ± 2235 (SD) mm and an average concentration of 2682 ± 827 items per kg of dry weight, being the total number of items found 1,019. Fourier Transform Infrared microscopy analysis of 13.9% (n = 139) of the microfibers also showed that they were mainly cellulosic (81.3%). No significant differences were found between the depths of the sediment. However, significant differences were found between the number of fibers from the sampling sites at the east and west of the island. Such variability could be driven by the winds and ocean mesoscale dynamics in the area. This study confirms the wide distribution of microfibers in sediments from an oceanic island like La Palma, providing their first report in marine sediments of the Canary Islands.

Microplastic contamination and characteristics spatially vary in the southern Black Sea beach sediment and sea surface water

In this study, the abundance, and characteristics of the microplastics on the southern coast of the Black Sea were assessed. More than 70% of the detected microplastics were smaller than 2.5 mm and mostly consisted of fibers and fragments. The average microplastic abundance in the beach sediment and seawater were 64.06 ± 8.95 particles/kg and 18.68 ± 3.01 particles/m³, respectively. The western coast of the study area (Marmara region) was the most polluted area, and a spatially significant difference was determined in terms of abundance. The composition in the beach sediment (particles/kg) was dominated by styrene acrylonitrile copolymer (SAC) (40.53%), polyethylene terephthalate (PET) (38.75%), and polyethylene (PE) (6.91%), whereas the seawater (particles/m³) was dominated by PET (57.26%), PE (13.52%), and polypropylene PP (11.24%). The results of our study can be a baseline for environmental modeling studies and experimental studies on the marine organisms inhabiting the Black Sea.

Critical review of the characteristics, interactions, and toxicity of micro/nanomaterials pollutants in aquatic environments

A wide range of contaminants of emerging concern such as micro/nanoplastics (MPs/PNPs) and metal-nanoparticles (Me-NPs) from anthropogenic activities have been identified in aquatic environments. The hazardous effects of these micro/nanomaterials as pollutants in organisms and the lack of knowledge about their behavior in aquatic environments have generated growing concern in the scientific community. The nanomaterials have a colloidal-type behavior due to their size range but with differences in their physicochemical properties. This review comprises the behavior of micro/nanomaterials pollutants and the physicochemical interactions between MPs/PNPs and Me-NPs in aquatic environments, and their potential toxicological effects in organisms. Moreover, this article describes the potential use of Me-NPs to remove MPs/PNPs present in the water column due to their photocatalytic and magnetic properties. It also discusses the challenge to determine harmful effects of micro/nanomaterials pollutants in organisms and provides future research directions to improve integrated management strategies to mitigate their environmental impact.

An annual study on plastic accumulation in surface water and sediment cores from the coastline of Tenerife (Canary Island, Spain)

Sediment core samples from high tide lines and in submerged zones as well as surface water samples from eight beaches of Tenerife were analysed. Sampling was conducted over a period of one year in intervals of 5 weeks. The majority of particles were found in the high tide sediment (66%), followed by water samples (23%) and finally in sediment from submerged zones (11%). Regarding the particle amount per volume (items/L), accumulation in sediment samples was statistically higher compared to water samples. Mean values of items/L were higher in high tide sediments. In high tide and water samples, mostly white and transparent particles >1 mm were found. More than 70% were represented by fragments. In sediments from submerged zones, yellow and blue microparticles (<1 mm) were predominant and 61.9% consisted of fibres. Larger particles were mainly identified as PP, PE, PS, PTFE and PVC, while polymer types of smaller particles were more variable.

Microplastics in bivalves, water and sediments from a touristic sandy beach of Argentina

This study assesses for the first time the concentrations of microplastics (MPs) in sediments, water and two human-consumed mussels with different ecological traits (Amarilladesma mactroides and Brachidontes rodriguezii) in a touristic sandy beach of Argentina. MPs were characterized through FTIR and SEM/EDX techniques. All the samples presented MPs with similar concentrations as other human-impacted coastal areas of the world, being black and blue fibers of < 0.5 and 0.5-1 mm the most abundant. SEM images exhibited cracks and fractures with clay minerals and microorganisms adhered to MPs surface. EDX spectrums showed potentially toxic elements, such as Cr, Ti, and Mo. FTIR identified polymers such as cellulose, polyamides, and polyacrylates in most of the samples analyzed. Our study demonstrates that microplastic pollution is a common threat to sandy beaches in Argentina, worsened by plastic particles carrying metal ions with potential toxic effects to the biota, including A. mactroides, an endangered species.

The microplastic pollution in beaches that served as historical nesting grounds for green turtles on Hainan Island, China

This study evaluated microplastic pollution in beaches that have served as historical nesting grounds for green turtles in Hainan Island, China and explored the sources of microplastic pollutants to conduct habitat restoration for sea turtles. The average abundance of the microplastics in the beach surface sediments was 2567.38 ± 2937.37 pieces·m^-2 or 641.85 ± 734.34 thousand pieces·m^-3, foam and plastic block were the main microplastics identified. Microplastic size was predominantly within the 0.05-1 mm category (small microplastic particles), and most microplastic particles were white. Polystyrene and polyethylene were the dominant plastic compositions. The type and compositions of microplastics indicate that most microplastics in this study were broken from large plastic blocks and foam. To reduce the threat of microplastic pollution to marine life, including sea turtles, we suggested removing plastic litter, especially small plastic on beaches, and replacing and recovering the foam used in aquaculture before it ages and fragments.

Stranded in the high tide line: Spatial and temporal variability of beached microplastics in a semi-enclosed embayment (Arcachon, France)

Coastal environments are a predominant ultimate destination of marine debris, becoming a key focus of studies assessing microplastic (MP) contamination. Here, we described the visible fraction of MP (from 0.5 to 5 mm) that washed up during the high tide at different sites of a semi-enclosed mesotidal bay and investigated the main abiotic factors driving MP beaching. Three contrasted beaches of the Arcachon Bay (SW France) were monitored on a monthly basis during 2019. Samplings were made along a 100 m longitudinal transect at the high-water strandline (4 quadrats of 0.25m²) and at an intermediate tidal range. Each sampled particle was characterized by morphometric data (e.g. size, shape, color, roughness) and polymer identification was performed by ATR-FTIR technique. Results show that MP concentration was higher on the beach located at the mouth of the bay (36.0 ± 39.2 MP.m^-2) than at the back and the outside of the bay (respectively 2.7 ± 4.4 and 1.7 ± 2.4 MP.m^-2). This may be related to the strong currents at the entry of the embayment and the beach orientation, exposed to predominant winds. Beached MP were mainly pre-production pellets and fragments as they represented respectively 49% and 39% of all analyzed shapes. Polymers with low density were particularly abundant. Polyethylene represented 69% of all the particles while polypropylene accounted for 17% and polystyrene for 10%. We also observed that MP were mostly washed up when wind, waves and river flow were more intense. Analysis suggest that wind direction and speed are key factors influencing beaching as strong onshore wind enhance this process.

Characteristics of expanded polystyrene microplastics on island beaches in the Pearl River Estuary: abundance, size, surface texture and their metals-carrying capacity

While expanded polystyrene (EPS) microplastics have been widely recognized as one of the most important components of plastic litter in the intertidal zones of the global ocean, our understanding of their environmental fate on island beaches is insufficient. In this study, we intended to reveal that the latest EPS microplastic pollution status on 5 island beaches in the Pearl River Estuary, China, by comprehensively assessing the abundance, distribution, size, surface texture and carrying capacity of heavy metals (Cd, As, Cr, Ni, Cu, Pb, Mn, Fe, Al). High level of EPS microplastic abundance ranged from 328 to 82,276 particles m^-2 was found, with the highest abundance at Guishan Island and the lowest at Dong'ao Island. Spatial distribution of EPS microplastic abundance was significantly different among different islands. EPS microplastics in the size range of 1-2 mm were the most abundant. The content of heavy metals in EPS microplastics collected on the beaches was greater than that in the new EPS products. The average concentrations of heavy metals in EPS microplastics from 5 islands are Cd (0.27 ± 0.19 μg g^-1), As (5.50 ± 3.84 μg g^-1), Cr (14.9 ± 8.25 μg g^-1), Cu (15.0 ± 7.66 μg g^-1), Ni (17.2 ± 17.6 μg g^-1), Pb (24.8 ± 7.39 μg g^-1), Mn (730 ± 797 μg g^-1), Fe (8340 ± 4760 μg g^-1), and Al (9624 ± 6187 μg g^-1), respectively. The correlation between heavy metals in EPS microplastics and sediments was better than that between heavy metals in EPS microplastics and seawater. The study results indicated that EPS microplastics could act as a carrier for the transport of heavy metals, which might pose a threat to biological and human health.

Distribution and transport of microplastics in the upper 1150 m of the water column at the Eastern North Atlantic Subtropical Gyre, Canary Islands, Spain

Nowadays it is widely known that pollution by microplastics (MP) at the open ocean covers immense areas. Buoyant plastics tend to accumulate in areas of convergence at the sea surface such as subtropical gyres, while non-buoyant plastics accumulate at the seafloor. However, previous studies have revealed that the total amount of plastic in the different oceans is not well correlated with the concentrations measured at the sea surface and the sea floor, evidencing a significant amount of missing plastic in the oceans. This deviation could be related to an underestimation of the role played by small fragments of plastic and fibers in the oceans. Furthermore, microplastic fragments with a density lower than the density of seawater have been gathered hundreds of meters below the sea surface in the Pacific Ocean due to their size and shape. The main objective of this study is to carry out, for the first time, an equivalent analysis along the water column for the Atlantic Ocean. In that sense, a total number of 51 samples were collected during four different oceanographic cruises between February and December 2019, from the sea surface down to 1150 m depth at the open ocean waters of the Canary Islands region (Spain). For each sample, 72 l of seawater were filtered on board with a mesh size of 100 μm, where the presence of microplastics has been clearly observed. Our results reveal the presence of microplastics at least up to 1150 m depth, at the Northeastern Atlantic Subtropical Gyre with noticeable seasonal differences. The spatial distribution of these small fragments and fibers at the water column is mainly related to the oceanic dynamics and mesoscale convective flows, overcoming the MP motion induced by their own buoyancy. Moreover, these microplastics have being transported by the ocean dynamics as passive drifters.

Transport, weathering and pollution of plastic from container losses at sea: Observations from a spillage of inkjet cartridges in the North Atlantic Ocean

Observations of beached polypropylene inkjet cartridges, spilled from a ship container lost in the North Atlantic Ocean, have been compiled through calls on international social media. Within a period of four years from the spillage, a total of about 1500 cartridges was reported in locations as far apart as Florida and northern Norway. The distribution of cartridges reflected the principal surface currents in the ocean, with some carried by the Azores and Canary currents around the North Atlantic Gyre, and others transported northwards with the North Atlantic and Norwegian currents. Along the shorelines of the UK and Ireland, there was a clear, preferential accumulation of cartridges on west- and south-facing coasts, consistent with the direction of the North Atlantic current and the heading of the principal winds. Dates of first sightings in various regions throughout the North Atlantic (and as reported on social media) suggested that cartridges traveled on average at around 6-13 cm s^-1. These observations and estimates were largely consistent with simulations of the dispersion of free floating, neutrally buoyant particles from the spillage site derived from PlasticAdrift, an empirical model based on drifter tracking data. Microscopic and X-ray fluorescence analyses of selected cartridges revealed a high degree of exterior weathering, resulting in chalking and embrittlement of the polypropylene and the formation of microplastics rich in Ti, chemical fouling of interior ink foams (where still present) by Fe oxides, and, in some cases, the presence of an electronic chip containing Cu, Au and brominated compounds. Significantly, the latter characteristic renders cartridges as electrical and electronic waste and means that current, conventional regulations on plastic cargo lost at sea are not applicable here. More generally, the study highlights the potential usefulness of social media-led citizen science to marine research, and inadequacies in the relevance and robustness of instruments and conventions that deal with plastic waste in the ocean.

Environmental status of marine plastic pollution in Spain

The excessive use of plastic in our society is causing a massive accumulation, since it is a non-biodegradable product and with still poor recycling rates. This effect can be observed in the seas, which more and more plastic waste are accumulating. The present work is a critical review, based on all currently available literature, that reports environmental status of marine plastic pollution, especially microplastic pollution, in Spain. The three Spanish water areas with the highest presence of plastics are the Alboran Sea, the Gulf of Alicante and the vicinity of Barcelona probably related to fishing and industrial activities and high population densities. With regard to microplastic contamination on beaches in Spain, annual monitoring by the Spanish government shows contamination along the entire coast of the country, with particularly high concentrations in the Canary Islands (between 800 and 8800 particles/m² in spring). Between 40 and 50% of the particles analyzed were pellets and the main factors postulated for the distribution of these particles are marine currents and the geomorphological characteristics. With regards to biota, ingestion of microplastics by fish has been intensely confirmed and, important differences were observed between the locations of the sampling, being bogues (Boops boops) one of the fish species more studied in Spain. Finally, the work includes a revision of European and Spanish legislation about plastics and marine pollution and some strategies to reduce this kind of contamination in Spain.

Suborganismal responses of the aquatic midge Chironomus riparius to polyethylene microplastics

Freshwater riverbeds are a major repository of microplastics (MPs) from inland activities. Benthic macroinvertebrates that live in close contact with sediments seem to ingest a considerable amount of such plastic particles. The effects of MPs on life-history traits are relatively well-known, but the suborganismal mechanisms underlying such effects remain unclear. This study addressed the potential effects of low-density polyethylene (LDPE) MPs on Chironomus riparius larvae at cellular and molecular levels. Fourth instar C. riparius larvae were exposed to 0.025 and 2.5 g/kg LDPE of dry sediment (sizes: <32 and 32-45 μm; with irregular shape) under laboratory conditions for 48 h. These short-term exposures to environmental concentrations of LDPE MPs induced changes in the energy reserves (mostly by decreasing carbohydrates and increasing lipids), increased antioxidant and detoxification responses (tGSH, CAT, and GST), and induced increases in the activity of AChE (related to neurotransmission). In addition, at the gene level, exposure to MPs modified mRNA levels of InR, Dis, EcR, Dronc, Met (endocrine system), Def (immune system), PARP, ATM, NLK, and Decay (DNA repair), generating important alterations in the C. riparius development and response to unfavorable situations. This study provides new evidence of the effects of LDPE MPs at the suborganismal level, filling the gap in knowledge regarding the mechanisms underlying the toxicity of MPs and spotlighting gene expression analyses as early indicators of MP toxicity in C. riparius which were confirmed by Integrated biomarker response analyses highlighting the gene expression as sensible and useful endpoints for LPDE pollution in freshwaters. These results, coupled with previous investigations on responses at the organismal level, emphasizes the potential adverse effects of LDPE MPs on C. riparius, which may compromise freshwater benthic communities, considering its ecological role within these habitats.

Arenas Blancas (El Hierro island), a new hotspot of plastic debris in the Canary Islands (Spain)

The present work has studied the incidence and type of micro (1-5 mm), meso (5-25 mm) and macroplastics (>25 mm) that have reached Arenas Blancas beach, located in the north coast of El Hierro island, in the Canary Islands (Spain), from October 2019 to May 2020 (13 sampling dates with 3 sampling points each). Taking into consideration the three studied plastic debris fractions (macro, meso and microplastics), a total of 9206 items were found, which had a total weight of 1169.7 g and a concentration of 891.3 ± 91.5 items/m² (118.3 ± 17.8 g/m² and 2.3 ± 0.4 g/L). Regarding their colour, most of them were transparent/white/clear, especially in the microplastic fraction in which they accounted for a 68% of the total. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy of meso and microplastic fractions indicated that most of the particles were either polypropylene and polyethylene followed by polystyrene in a much lower amount. In general, the total amount of plastic debris that arrives to the beach by the persistent oceanic current pattern linked to the easternmost branch of the North Atlantic Subtropical Gyre is comparable to those of the most contaminated beaches of the Canary Islands archipelago, suggesting that a new hotspot of plastic debris arrival has been found.

UV filters and UV stabilisers adsorbed in microplastic debris from beach sand

Microplastics (MPs) in oceans adsorb different types of pollutants, which can negatively impact the food chain. The extensive use of personal care products (PCPs) has led to their ubiquitous environmental presence, and their partition between plastic matrices and surroundings is determined by their physico-chemical characteristics and environmental conditions. This work develops and applies a methodology to determine 12 UV filters (UVFs) and UV stabilisers (UVSs) in MPs collected in beach sand. The analyses were carried out by ultrasound-assisted extraction and ultrahigh-performance liquid chromatography with tandem mass spectrometry detection. The validated procedure was applied to MPs samples taken in sand samples from 13 beaches on the Canary Islands (Spain). The results showed the presence of 10 UV filters and UV stabilisers at concentrations between 1 and 4031 ng·g^-1, where octocrylene was the most frequently found. The target analytes were present in all the sampling beaches.

Distribution, characteristics and short-term variability of microplastics in beach sediment of Fernando de Noronha Archipelago, Brazil

Fernando de Noronha Archipelago is highly vulnerable to microplastic pollution, which has been previously reported with snapshot samplings on the site. The present study has performed daily beach sediment samplings on the archipelago, aiming to assess the distribution, characteristics and short-term variability of microplastics (1-5 mm), expressing concentrations in three different units. The concentrations ranged from 0.6 ± 2.5 particles/m² to 1059.3 ± 1385.6 particles/m² and showed a large spatial and temporal small-scale variability. The results indicate that microplastic contamination is recurrent in Fernando de Noronha and the distribution of these particles is associated with a combination of various physical processes. A wider comparison with results obtained in beaches worldwide was possible using different units of concentration, but standard methods for sampling and analysis of microplastics is needed to better understanding of large-scale spatial and temporal variability.

Microplastic ingestion in jellyfish Pelagia noctiluca (Forsskal, 1775) in the North Atlantic Ocean

The present study is the first evidence-based study about the ingestion of plastic and microplastics in jellyfish Pelagia noctiluca in the North Atlantic Ocean. A bloom of this organism was collected from Gran Canaria Island coast. It was digested using KOH to quantify the plastic particles and by separating the umbrella from tentacles. About 97% of the organisms analysed showed the presence of microdebris. The majority of the microfibers were with blue or uncorrected fibre concentrations and mainly composed of cotton. Their presence in the gastrovascular cavity of the jellyfish was confirmed. These results warn about the impact of various factors such as jellyfish health, the transfer to jellyfish predators, human consumption of jelly fish, and the transport of carbon and microplastics in the water column.

Microplastic pollution on sandy beaches of Puerto Rico

Caribbean islands, including Puerto Rico, are biodiversity hotspots threatened by microplastics (<5 mm). Little is known about the extent of microplastic pollution in coastal sandy beaches of Puerto Rico. Sand from six northern beaches was collected in the high tide line to determine microplastic abundance (0.3-4.75 mm). Península La Esperanza, the most polluted beach, exhibited higher average abundance (17 items/kg dw) and diversity. High urbanization, industrial/port activities, and riverine input are likely sources of plastic debris on this beach. The other beaches showed lower and similar average abundance (3 to 7 items/kg dw) despite having distinct potential point and non-point sources. Overall, fibers (40%), fragments (28%) and foams (27%) predominated (n = 102 particles). Results showed comparable levels to other world beaches, some classified as highly contaminated, but only when transforming units to items/m². Preliminary ATR-FTIR analysis identified mainly polyethylene. It is imperative to have plastics source reduction through waste management.

Potential human health risks due to environmental exposure to nano- and microplastics and knowledge gaps: A scoping review

Microplastics are an emerging global environmental contaminant that are affecting multiple spheres. Despite their ubiquity in all spheres of life and ecology, little is known about the health effects of microplastics exposure to humans. This scoping review explores the existing evidence on the potential human health effects of microplastics and subsequent knowledge gaps. An electronic search of published articles in PubMed, Scopus, EMBASE, Cochrane databases, and Google Scholar was conducted using a combination of subject headings and keywords relating to microplastics and human health effects. The initial search resulted in 17,043 published articles and grey literature documents. After a full review of published articles and their references, 129 publications were identified for further detailed review. These articles indicate that human exposure to microplastics can occur through ingestion, inhalation, and dermal contact due to their presence in food, water, air, and consumer products. Microplastics exposure can cause toxicity through oxidative stress, inflammatory lesions, and increased uptake or translocation. Several studies have demonstrated the potentiality of metabolic disturbances, neurotoxicity, and increased cancer risk in humans. Moreover, microplastics have been found to release their constituent compounds as well as those that are adsorbed onto their surface. Further research is needed to quantify the effects of microplastics on human health and their pathogenesis.

Microplastic contamination in surface waters of the Küçükçekmece Lagoon, Marmara Sea (Turkey): Sources and areal distribution

The distribution of freshwater and marine microplastics (MPs) varies due to the difference in fresh and seawater densities and MP sources. This study aims to investigate the abundance of MPs and their possible sources in surface waters of different ecosystems, such as sea, lagoon, and lake. We classified MPs in terms of their color and type and established the relationship between the MPs in surface waters with different characteristics. The mean MP abundance (33 particles L^-1) detected herein was higher than that in the previously conducted studies. Fragment particles (37.95%) were determined to be the dominant MP type, and the predominant MP color was blue (75.28%). As for the seasonal MP distribution, its highest content (48.03 particles L^-1) was observed in autumn, unlike that reported by other studies. The findings of this study reveal the effects of wastewater treatment plant (WWTP) discharge and current flow on the MP distribution in the study area. This study aims to provide representative data on the MP abundance and distribution, as well as MP-affecting parameters for similar aquatic areas in other parts of the world.

Marine litter arrived: Distribution and potential sources on an unpopulated atoll in the Seaflower Biosphere Reserve, Caribbean Sea

The Albuquerque atoll was studied as a representative natural laboratory to explore the role of sea-based sources of marine litter. This work aimed to identify the small-scale spatial distribution of marine litter (i.e., plastic, glass, paper, and others) as well as to explore the connectivity among the atoll habitats (sand beach, water surface, and reef) to give insights of potential sources of marine litter (>5 cm), mainly plastics. Marine litter was dominated by plastic items, as expected, with an average value of 0.5 items/m². Large microplastics (1-5 mm) were also sampled on beaches with an average value of 90 particles/m². In the atoll inner lagoon, marine litter was also composed by plastic, mainly fragments (average 0.059 items/m³). The predominance of plastic fragments on both the sea surface and beaches of the atoll makes inferences on sources limited. However, o fishing activities and sea-based sources might be relevant since local sources are very limited.

Beaches of the Azores archipelago as transitory repositories for small plastic fragments floating in the North-East Atlantic

Plastic pollution is among the most pervasive stressors currently influencing the marine environment and affecting even the most remote areas. To date, there are still fundamental gaps in our understanding of the major pathways and fate of plastic debris in the oceans. Here we show that oceanic insular environments are important transitory repositories of small plastic items floating in the open ocean. Monthly monitoring of seven beaches over a three-year period demonstrate that beaches of the Azores islands with particular characteristics can capture significant quantities of fragments between 2 and 5 mm in length. The beach with the highest plastic loading rates was found to occasionally accumulate densities exceeding 15,000 fragments m^-2 on part of the backshore. However, a large portion of these fragments can be rapidly washed back into the marine environment. Detailed characterization of those plastic items revealed the typology and size distribution to be similar throughout the seven beaches and through the 33 months surveyed, suggesting a same and unique source. Our results show that these oceanic islands of the North-East Atlantic are under pressure of high quantities of fragmented plastic debris that probably entered the ocean many years ago.

Microplastics in aquatic environments: Toxicity to trigger ecological consequences

The prevalence of microplastic debris in aquatic ecosystems as a result of anthropogenic activity has received worldwide attention. Although extensive research has reported ubiquitous and directly adverse effects on organisms, only a few published studies have proposed the long-term ecological consequences. The research in this field still lacks a systematic overview of the toxic effects of microplastics and a coherent understanding of the potential ecological consequences. Here, we draw upon cross-disciplinary scientific research from recent decades to 1) seek to understand the correlation between the responses of organisms to microplastics and the potential ecological disturbances, 2) summarize the potential ecological consequences triggered by microplastics in aquatic environments, and 3) discuss the barriers to the understanding of microplastic toxicology. In this paper, the physiochemical characteristics and dynamic distribution of microplastics were related to the toxicological concerns about microplastic bioavailability and environmental perturbation. The extent of the ecological disturbances depends on how the ecotoxicity of microplastics is transferred and proliferated throughout an aquatic environment. Microplastics are prevalent; they interfere with nutrient productivity and cycling, cause physiological stress in organisms (e.g., behavioral alterations, immune responses, abnormal metabolism, and changes to energy budgets), and threaten the ecosystem composition and stability. By integrating the linkages among the toxicities that range from the erosion of individual species to the defective development of biological communities to the collapse of the ecosystem functioning, this review provides a bottom-up framework for future research to address the mechanisms underlying the toxicity of microplastics in aquatic environments and the substantial ecological consequences.

Pump-underway ship intake: An unexploited opportunity for Marine Strategy Framework Directive (MSFD) microplastic monitoring needs on coastal and oceanic waters

Broad scale sampling methods for microplastic monitoring in the open ocean waters remain a challenge in oceanography. A large number of samples is required to understand the distribution, abundance and fate of microplastic particles in the environment. Despite more than a decade of widespread study, there is currently no established time series of microplastic measurements and the research community is yet to establish a standardised set of methods that will allow data to be collected in a quick, affordable and interoperable way. We present a sampling technique involving the connection of a custom-built microplastic sampling device to the pump-underway ship intake system of a research vessel (RV) as an unexploited opportunity for oceanic monitoring needs concerning microplastic abundance and distribution. The method is cost effective, highly versatile and accurate, and is able to sample particles down to 50μm from opportunity platforms, thus contributing to an emerging area of study, and in particular helping to increase the monitoring reporting of data, and thereby serving as a valuable aid for the implementation of the Marine Strategy Framework Directive (MSFD). Sampling was performed during three consecutive oceanographic cruises in the subtropical NE Atlantic over a year, sampling subsurface waters (4 m depth) during navigation and while on coastal and oceanic stations. Microplastic particles were found in all stations and transects sampled. Fibres (64.42%) were predominant over fragments (35.58%), with the concentration values falling within the ranges of data reported for other areas of the Atlantic.

Physical characterization of litter and microplastic along the urban coast of Cagayan de Oro in Macajalar Bay, Philippines

There are limited litter and microplastic (MP) studies in the Philippines despite the fact that is has one of the longest shorelines that is possibly threatened by waste disposal. This study was carried out to determine the litter and MP in surface sand samples in a highly urbanized coastal environment of Cagayan de Oro in Macajalar Bay, Philippines. The flotation and stereomicroscope identification methods were employed to study MP, while litters were counted to extrapolate the clean coast index (CCI). Overall, MP fibers were found ubiquitously with site-specific abundance. Particularly, the residential site adjacent to the river mouth had the highest litter and MP fiber counts. The built environment like the seaport showed fragmented forms of MP. Likewise, CCI analysis showed an extremely dirty beachfront (CCI = 85) which mainly caused by plastic litters. Overall, the highly urbanized coastal environment may accumulate a distinct form of plastics. This study is preliminary and may underestimate plastic analysis owing to the limited sampling.

Sources, transport, measurement and impact of nano and microplastics in urban watersheds

The growing and pervasive presence of plastic pollution has attracted considerable interest in recent years, especially small (< 5 mm) plastic particles known as 'microplastics' (MPs). Their widespread presence may pose a threat to marine organisms globally. Most of the nano and microplastic (N&MP) pollution in marine environments is assumed to originate from land-based sources, but their sources, transport routes, and transformations are uncertain. Information on freshwater and terrestrial systems is lacking, and data on nanoplastic pollution are particularly sparse. The shortage of systematic studies of freshwater and terrestrial systems is a critical research gap because estimates of plastic release into these systems are much higher than those for oceans. As most plastic pollution originates in urban environments, studies of urban watersheds, particularly those with high population densities and industrial activities, are especially relevant with respect to source apportionment. Released plastic debris is transported in water, soil, and air. It can be exchanged between environmental compartments, adsorb toxic compounds, and ultimately be carried long distances, with potential to cause both physical and chemical harm to a multitude of species. Measurement challenges and a lack of standardized methods has slowed progress in determining the environmental prevalence and impacts of N&MPs. An overall aim of this review is to report the sources and abundances of N&MPs in urban watersheds. We focus on urban watersheds, and summarize monitoring methods and their limitations, knowing that identifying N&MPs and their urban/industrial sources is necessary to reduce their presence in all environments.

First evaluation of neustonic microplastics in the Macaronesian region, NE Atlantic

Marine microplastic pollution is an issue of great concern nowadays since high concentrations have been detected in the ocean, mainly in the subtropical gyres that accumulate this type of debris. The long-term effects of this pollution on ecosystems and marine biota are still unknown. The aim of this study is to quantify and characterise microplastics and neustonic zooplankton in sub-surface waters of the Macaronesian region, an area that has been little studied to date. Our results show a great variability in the concentration of microplastics with values between 15,283 items/km² in Los Gigantes (Tenerife, Canary Islands) and 1,007,872 items/km² in Las Canteras (Gran Canaria, Canary Islands). The main types of debris found were plastic fragments and fibres. The abundances of neustonic zooplankton were also very variable between the different sampling areas, being the main components copepods and eggs. Regarding the microplastics-zooplankton ratio, values were obtained between 0.002 and 0.22. In Las Canteras, the highest accumulation zone, was found twice as much microplastics as zooplankton for the 1-5 mm fraction in dry weight. These values highlight the potential hazard of microplastics - and its associated chemical contaminants - for marine biota, especially for large filter feeders.

Study of plastic pollution and its potential sources on Gran Canaria Island beaches (Canary Islands, Spain)

In order to understand the origin of plastic debris pollutants that accumulate in the Canary Islands coastline, six beaches of Gran Canaria Island were studied during different seasons to estimate the abundance and the types of two microplastics fraction sizes (0.01-1 mm and 1-5 mm) and mesoplastics fraction (5-25 mm). For the larger fraction of microplastics and mesoplastics, a high percentage of fragments and foams were found; moreover, both fractions show the same accumulation pattern in relation with the wave, wind, and current. The debris was checked for exogenous and local origins. Moreover, for the smaller fraction of microplastics, only natural, semi-synthetic, and synthetic fibres were found, showing a totally different spatial distribution from the others fractions. This result suggests a possible endogenous origin of the contamination, in relation to the type and amount of wastewater discharges and beach users.

Effects of spatial and seasonal factors on the characteristics and carbonyl index of (micro)plastics in a sandy beach in Aveiro, Portugal

Coastal environments are highly contaminated with plastics of various sizes. In order to understand the distribution and factors influencing (micro)plastics contamination in the environment, sampling of a sandy beach in Costa Nova, Aveiro, Portugal, was conducted by collecting plastic particles and sediments for density separation in transects from the mean low tide line to the dunes, during wet and dry seasons. For surface collection, microplastics comprised 69.4% of plastics, presenting concentrations of 3-6 items m^-2 in the wet season, mostly polyethylene pellets carried ashore by storms, and <1 item m^-2 for dry season, lower due to less backwashing, were found. Collection of infrared spectra of these particles allowed characterization by polymer type and carbonyl index of all particles. Variations in carbonyl index were found to be related to season, site and particle color. Density separated microplastics, mostly fibers, presented 23 times higher concentrations than surface collection (22 microplastics kg^-1, 280 microplastics m^-2), due to the identification of smaller sizes, and with higher concentrations in dry seasons, likely from accumulation in sediment and bathing season. Overall, different sampling methods allowed identification of different particle types and sizes, which may vary according to seasonal and spatial factors.

Plastic pollution on eight beaches of Tenerife (Canary Islands, Spain): An annual study

Stranded marine debris from eight beaches of Tenerife (Canary Islands, Spain) was analyzed. Sampling was conducted along the high tide line every 35 m over the whole lengths in periods of 5 weeks for one year. Evaluated particles included all materials bigger than 2 mm, which were subdivided in Mesoparticles (2-10 mm) and Macroparticles (>10 mm). There was a great variability of plastic abundance regarding the locations and the sampling dates. In contrast, the occurrence of debris along the beaches showed consistency and even zones of high and low accumulation. The most polluted beach was Poris, which is indeed infrequently visited, but highly affected by the main current. Plastic particles were principally mesoparticles and white/transparent color. This study not only confirms, that the Canary Islands are highly affected by the marine plastic pollution, but also for the first time shows, that stranded plastic accumulates in restricted areas of sandy coastlines.