The plastic in microplastics: A review

Microplastics affect sedimentary microbial communities and nitrogen cycling

Microplastics are ubiquitous in estuarine, coastal, and deep sea sediments. The impacts of microplastics on sedimentary microbial ecosystems and biogeochemical carbon and nitrogen cycles, however, have not been well reported. To evaluate if microplastics influence the composition and function of sedimentary microbial communities, we conducted a microcosm experiment using salt marsh sediment amended with polyethylene (PE), polyvinyl chloride (PVC), polyurethane foam (PUF) or polylactic acid (PLA) microplastics. We report that the presence of microplastics alters sediment microbial community composition and nitrogen cycling processes. Compared to control sediments without microplastic, PUF- and PLA-amended sediments promote nitrification and denitrification, while PVC amendment inhibits both processes. These results indicate that nitrogen cycling processes in sediments can be significantly affected by different microplastics, which may serve as organic carbon substrates for microbial communities. Considering this evidence and increasing microplastic pollution, the impact of plastics on global ecosystems and biogeochemical cycling merits critical investigation.

Evidence of microplastics (MP) in gut content of major consumed marine fish species in the State of Kuwait (of the Arabian/Persian Gulf)

Microplastics (MP), the debris that collectively refers to plastic fragments and particles of <5 mm in size within marine environments, has been the subject of interest within the past decade. Evidence of its occurrence and abundance, has been recorded in this communication after examining gastrointestinal specimens of eight commercially available fish species common to the Arabian (Persian) Gulf acquired locally from the State of Kuwait. The species studied belonged to different trophic levels, and the specimens were subjected to Micro Raman and Micro Fourier Infrared Spectroscopy (FTIR) in Attenuated Reflective Mode (ATR) to determine the presence and type of polymer of the MP. The detected MP set a president for the first time in the examined fish species within the State of Kuwait, which are of immense commercial importance. Various particles were detected, and three MP particles (fragments) were detected within the guts of Acanthopagrus latus, Eleutheronemaa tetradactylum and Lutjanus quinquelineatus. Based on the nature and behaviour of these particular fish types which prefer to stay in muddy waters and sheltered lagoons, it is suspected that common primary sources of MP (i.e. waste fragmentation) have led to passive/active intake (e.g. detritus ingestion) of these particles (fragments) by these species of fish in Kuwait.

Identification and visualisation of microplastics/nanoplastics by Raman imaging (i): Down to 100 nm

While microplastics (1 μm-5 mm) contamination is creating public concern, nanoplastics (<1000 nm) might create even more serious environmental contamination issues. This is likely due to the smaller size/higher specific surface area of nanoplastics which works more efficiently as a vector for other contaminants' transportation and fate, to release the formulation additives and to be accumulated in the human body. The research on nanoplastics is currently hampered by the absence of an effective characterisation method, although X-ray photoelectron spectroscopy/Scanning Electron Microscopy (XPS/SEM) is reportedly dominating the nanoplastics characterisation approaches. Recently, imaging technology, which provides direct visualisation of the targets, is attracting increased attention. In this study, we demonstrate that Raman imaging can be employed to visualise and identify microplastics and nanoplastics down to 100 nm, by distinguishing the laser spot, the pixel size/image resolution, the nanoplastics size/position (within a laser spot), the Raman signal intensity, and via the sample preparation etc. We also validate this technique for the analysis of paint-polishing dust samples that have been collected from a driveway when a vehicle's clear coating of poly-acrylic was polished by hand. We estimate that billions-trillions of microplastics/nanoplastics ranging from ∼7 μm down to ∼200 nm have been generated by hand-polishing an engine hood.

Microplastics: an emerging threat to food security and human health

Microplastic presence in seafood and foodstuff have been documented globally in recent studies. Consequently, human exposure to microplastics through the ingestion of contaminated food is inevitable and pose a risk to food security and human health. In this review, microplastics and related xenobiotics are defined, global evidence of microplastic pollution in seafood is reviewed, the impacts to commercial marine species and food security are discussed, and the current knowledge of its direct effects on human health is reviewed. In addition, limited information regarding food security and scientific gaps are identified. Although microplastics in the marine environment and its effects on marine organisms have been well documented, more research is needed to completely understand the implications of microplastics over food security and human health. Further research must focus on monitoring and eliminating microplastics along the food supply chain and determining the extent to which food security is affected by microplastic pollution.

Marine debris on a tropical coastline: Abundance, predominant sources and fate in a region with multiple activities (Fortaleza, Ceará, northeastern Brazil)

The aim of the present study was to perform the first assessment of the abundance and classification of marine debris as well as determine the sources, transport and fate of this debris on an urbanized coast with multiple human activities. More than 80% of the marine debris was composed of synthetic materials. The beached marine debris was classified according to size. Meso-debris accounted for the highest portion of contamination (55%), followed by macro-debris (25.1%) and small debris (19.9%). Contamination by debris, such as cotton swabs (31%) and lollipop sticks (36.8%) accounted for the largest portion of the small debris class. Human recreational activities were the predominant source of debris, followed by navigation/fishing activities, domestic activities and industrial/port activities. The assessment of the predominance of human activities and the results of the model revealed a larger contribution of debris from recreational activities on nearby beaches on the small to larger scale and that rivers exert less of an influence due to the fact that they do not flow the entire year.

Microplastic particles in the Persian/Arabian Gulf - A review on sampling and identification

Microplastics are ubiquitous, persistent pollutants that are reported in abundance within the marine environment. Their presence in seawater and marine sediments poses a legitimate environmental and ecological concern for toxicity and food chain transfer via marine organisms. Their capability for sorption of other hydrophobic contaminants and the inability of the wastewater treatment plants to completely remove them pose additional risks. This review highlights the methodologies for sampling, sample preparation, and identification used in the Persian/Arabian Gulf region, which is possibly one of the least studied marginal seas with only sixteen papers published on microplastics. The review highlights the several orders of magnitude variations in microplastic concentrations among different studies; e.g. in seawater, only 12 microplastic particles were reported from 40 transects of one km length in Kuwait to 0.71 microplastics m^-3 in Qatar. Concentrations in beach sediments also show the significant difference between the northern and southern Gulf coasts, with 13 particles in 24 samples reported in Qatar, and 15 particles within 44 samples across Kuwait, to 3252 ± 2766 particles m^-2 from Bandar Abbas, Iran. The biota samples also show similar variances, with only three particles identified from 87 gut samples in Kuwait to 828 particles in 58 samples that include 46 fish and 12 shrimps from Iran. Some extremely high concentrations in biota are also reported from Iran, with concentrations as high as 0.251 particles g^-1 of muscle and 0.931 particles g^-1 in gills. It is evident that there is no consensus in the Gulf region on the sampling techniques (mesh size of plankton nets and sieves), use of fluidization solutions and very different units used in data reporting such as particles m^-3 and particles m^-2 in water samples. In sediments units like particles g^-1 and particles m^-2 have been used, and for biota it is the number of particles present in the sample, while others have quantified data as particles g^-1 of tissue. Considering the higher densities of PET, PVC, nylon and polyester than seawater, they are likely to migrate downwards into marine sediments, a transfer process that has not been studied in detail. Thus the review underscores the need to adopt harmonized protocols for microplastic studies in the region, and identifies certain aspects of microplastics that require further study.

Behavior and distribution of polystyrene foams on the shore of Tuul River in Mongolia

Foamed plastic debris in aquatic systems has become one of the emerging global contaminants. In this study, the behavior of polystyrene foam (PSF) and microplastics (MPs) adhered on the PSFs were investigated on the Tuul River shore in Ulaanbaatar, the capital city of Mongolia. The micro-sized (<5 mm) PSF, which was the dominant PSF over 600 pieces in 100 m², have accumulated along the shoreline of Tuul River. Carbonyl index (CI) was calculated to evaluate the surface oxidation of macro-sized (20-100 mm), meso-sized (5-20 mm), and micro-sized PSFs and confirm the relative aging depending on photodegradation. CI ranged from 0.00 to 1.09 in the sampled PSFs, whereby the degraded PSFs with high CI were distributed on the shore of downstream of sewer drainage. Micro-sized PSFs showed a wide range of CI and a relatively high average value of CI as compared to those of meso- and macro-sized PSFs. Most of PSFs aggregated with MPs and the adhered MPs have been ubiquitously detected from the surface of PSFs. Adhered micro-sized plastics explored from the surface of PSFs with various sizes, except for mega-sized (>100 mm) PSF, ranged from 5 to 141 items per piece of PSF fragment. The aggregates of PSFs and MPs were common status of PSFs during their transportation. The present findings, which indicated a high concentration of adhered MPs, raise an environmental concern about the widespread aquatic plastic pollution.

Microplastic pollution of the Tamsui River and its tributaries in northern Taiwan: Spatial heterogeneity and correlation with precipitation

The microplastic pollution and its effects on ecosystem in the marine environment has been well studied over the past decade. In contrast, the impact of microplastic pollution in freshwater environments was understudied, e.g., only a few studies examined the amount and distribution of microplastic in rivers, as well as the contribution of rivers to the microplastic pollution in oceans. In this study we investigated the microplastic pollution in the Tamsui River and its tributaries in northern Taiwan. We collected samples with a manta net from the Tamsui River, the Dahan River, the Keelung River and the Xindian River every two weeks over a time period of three months in 2018. Additionally, we took samples from the Xindian River during a heavy rain event in February 2019. Microplastic particles in the size range of 0.3-5 mm were visually identified. Unknown particles were identified using FTIR spectroscopy. The extracted particles were counted and classified according to their shape and color. We found microplastic of varying amounts in each of the samples, which indicates a wide spread pollution in the Tamsui River and its tributaries. The amount varies between rivers and ranges in average from 2.5 ± 1.8 particles per m³ in the Xindian River to 83.7 ± 70.8 particles per m³ in the Dahan River. Our data shows a positive correlation between precipitation and amount of microplastic particles found in the rivers. Moreover, in each river we could observe a large spatial and temporal variation of the microplastic amount between the left, middle and right sections of the stream. Due to this heterogeneous distribution of particles, we suggest that samples for microplastic analysis should be taken from multiple places across a river, as well as over a certain period to account for the heterogeneous microplastic distribution in the river water.

Sorption of three common nonsteroidal anti-inflammatory drugs (NSAIDs) to microplastics

High disposability, high durability, and indiscriminate use have led to the accumulation of plastics at uncontrolled rates in the environment. However, plastics are not the only source of water pollution in the environment. Nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of pharmaceuticals widely and highly consumed in the market due to a low price and over-the-counter accessibility. NSAIDs are frequently detected in surface water environments at μg L^-1 concentrations. In the present study, the sorption behavior of three NSAIDs (ibuprofen, naproxen, diclofenac) was examined with four types of microplastics (polystyrene (PS), ultra-high molecular weight polyethylene (UHMWPE), average molecular weight medium density polyethylene (AMWPE), and polypropylene (PP)), under varying water conditions. Low sorption occurred between NSAIDs and microplastics under environmentally relevant conditions. The sorption process exhibited a pronounced pH dependency due to the effect of pH on the speciation of the compounds and the surface charge of the particles. Only under acidic conditions (pH: 2), NSAIDs were highly sorbed onto microplastics mainly ruled by hydrophobic interactions. Among NSAIDs tested, diclofenac exhibited the highest sorption coefficients to microplastics. Polyethylene particles exhibited the highest affinity for NSAIDs.

Coupled effects of urbanization level and dam on microplastics in surface waters in a coastal watershed of Southeast China

Investigating the heterogeneous distribution pattern of plastic pollution in river systems is useful for better understanding the transport pathways of plastics from land to sea. Therefore, we analyzed samples from 17 sites to evaluate the distribution pattern of microplastics (MPs) in Minjiang River Watershed. The MP concentrations ranged between 0.12 and 2.72 n/L, with higher microplastic concentrations located in urban areas with greater population and gross domestic product (GDP) densities. MP concentrations were positively correlated with population density, GDP density, and built-up land use percentage, suggesting that increasing urbanization level will lead to greater plastic pollution. MP concentrations spanning the upstream and downstream sides of the SK Hydropower Dam showed decreasing trends, suggesting that MP settling would occur behind the dam and Shuikou Reservoir might serve as a sink for MPs. This study provides useful insight for revealing the effects of urbanization and dams on spatial distribution of riverine MPs.

Riverine anthropogenic litter load to the Mediterranean Sea near the metropolitan area of Barcelona, Spain

Every year >4 million tonnes of plastic are estimated to enter the oceans and much of it comes from land-based sources through rivers and estuaries. To fill the lack of information related to plastic inputs from rivers, a harmonized approach based on visual observations for monitoring floating macro litter was followed in this work. We provide the results of one-year monitoring (October 2016-September 2017) in the Llobregat and El Besòs rivers, which are flowing through an industrialized and populated area nearby the city of Barcelona (Catalonia, NE Spain). Floating litter items categories were influenced by urban centres located along the rivers. Overall, similar litter composition was observed in both rivers with a prevalence of plastics, mainly related to the food and beverage sectors. Seasonal variability showed significant correlations with natural factors such as wind and rainfall. Approximately 0.4-0.6 tonnes of plastic per year were estimated to be loaded into the sea by these two Catalan rivers. This study contributes to enlarge our knowledge on anthropogenic riverine litter entering the NW Mediterranean Sea, providing a starting point for the development of further mitigation strategies.

Unmanned Aerial Vehicles for Debris Survey in Coastal Areas: Long-Term Monitoring Programme to Study Spatial and Temporal Accumulation of the Dynamics of Beached Marine Litter

Unmanned aerial vehicles (UAVs) are becoming increasingly accessible tools with widespread use as environmental monitoring systems. They can be used for anthropogenic marine debris survey, a recently growing research field. In fact, while the increasing efforts for offshore investigations lead to a considerable collection of data on this type of pollution in the open sea, there is still little knowledge of the materials deposited along the coasts and the mechanism that leads to their accumulation pattern. UAVs can be effective in bridging this gap by increasing the amount of data acquired to study coastal deposits, while also limiting the anthropogenic impact in protected areas. In this study, UAVs have been used to acquire geo-referenced RGB images in a selected zone of a protected marine area (the Migliarino, Massacciuccoli, and San Rossore park near Pisa, Italy), during a long-term (ten months) monitoring programme. A post processing system based on visual interpretation of the images allows the localization and identification of the anthropogenic marine debris within the scanned area, and the estimation of their spatial and temporal distribution in different zones of the beach. These results provide an opportunity to investigate the dynamics of accumulation over time, suggesting that our approach might be appropriate for monitoring and collecting such data in isolated, and especially in protected, areas with significant benefits for different types of stakeholders.

Sorption Behavior and Mechanisms of Organic Contaminants to Nano and Microplastics

Nano and microplastics (NPs/MPs) have received widespread attention in recent years. Because of their large specific surface area and hydrophobicity, NPs/MPs can adsorb various organic contaminants. This article gives a brief review of the sorption behavior of organic contaminants to NPs/MPs, summarizes the possible sorption mechanisms, and analyzes the influencing factors in the environment on the sorption behavior and mechanisms of NPs/MPs. The main mechanisms of sorption of organic contaminants to NPs/MPs are partitioning, surface sorption (hydrogen bonding, π-π interaction, electrostatic interaction, and van der Waals force), and pore filling. The sorption behavior of organic contaminants to NPs/MPs is not only affected by the properties of the NPs/MPs and the organic contaminants, but also by the solution chemistry, such as the pH, ionic strength, and dissolved organic matter.

Occurrence and characterization of surface sediment microplastics and litter from North African coasts of Mediterranean Sea: Preliminary research and first evidence

The aim of this research work is to investigate the abundance of macroplastics and microplastics from North African coasts of Mediterranean Sea in the Gulf of Annaba (Algeria). The study areas are well known for the high population and high industrial activities that can contribute to the plastic pollution. In this case, microplastics were sampled from the surface sediments at four different stations representing different local activities. The microplastics were extracted by the density separation method from collected samples. Each particle was identified using Fourier transform infrared spectroscopy (ATR-FTIR). Furthermore, beach litters were obtained according to the adopted methodology - guidance on monitoring of marine litter in European seas. The obtained mean concentrations are 182.66 ± 27.32 and 649.33 ± 184.02 kg^-1 sediment (DW), respectively. A detailed spatial and quantitative analysis revealed that their distribution was a function of proximity to populated areas and associated with wastewater effluents, industrial installations, degree of shore exposure and complex tidal flow patterns. Five types of microplastics were identified; the most common were fibers (70%), fragments (21%), pellets (5%), films (2%) and foams (2%). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis showed that the main polymers detected in the studied microplastics were polyethylene (48%), polypropylene (16%), polyethylene terephthalate (14%), polystyrene (9%), butyl branham (7%), ethylene propylene (3%) and cellulose tri acetate (3%). The obtained results provided a holistic view of the abundance, distribution, and characteristics of microplastics in the Gulf of Annaba. This study confirmed the presence of microplastics in the Gulf of Annaba, albeit further studies remain necessary for better understanding of sources and fate.

Presence of microplastics in water, sediments and fish species in an urban coastal environment of Fiji, a Pacific small island developing state

Microplastics (MP) in the marine environment are widely reported. However, MP occurrence in some geographical areas such as from Small Island Developing States (SIDS) is missing. The main aim of this study was to assess MP levels in the urban coastal environment of Suva, the capital of the Republic of Fiji. Microplastics were measured from surface water, sediments and fish gastrointestinal tracts (GI) from three sites adjacent to Suva. In addition, an evaluation on the contribution from the local sewage treatment plant to MP levels was undertaken. In general, low levels of MP in water and sediments were detected, but significant differences were observed among sites. The sewage treatment plant was shown to contribute to MP levels in sediment but not in water. Species ingestion of MP was high and associated with MP in sediments. Fibres and fragments were the predominant type of MP, and fifteen different polymers were detected, with higher percentages of polyethylene, latex and polypropylene. In conclusion, MP were found in Suva coastal environment and these MP were associated to land based human activities.

Monitoring polymer degradation under different conditions in the marine environment

The perdurability of plastics in the environment is one of the major concerns of plastic pollution and, as a consequence, oceans are accumulating large amounts of plastic. The degradation of conventional and biobased materials was evaluated through a laboratory experiment for a year simulating four different conditions in the marine environment. The water column environmental compartment was simulated under euphotic and aphotic (with and without light availability) conditions. The seafloor environmental compartment was simulated with sediment under non-polluted and polluted conditions. By combining weight loss (%), spectroscopic and thermal analyses, the degradation patterns regarding the polymer structure were assessed. The studied biobased materials were polylactic acid (PLA) based materials and showed higher degradability than conventional ones. The weight loss of conventional materials was not influenced by the water column or sediment, while in PLA-based materials, the degradation rates were ca. 5 times greater in the sediment than in the water column. The absorbance (Abs) value at 3400 cm^-1 for polyethylene terephthalate (PET), and carbonyl (CO) index for PET and PLA could be useful to detect early signs of degradation. The crystallization index could be a useful parameter to discriminate degradation stages. The obtained results highlight the different degradability rates of materials depending on the specific environmental marine conditions.

Toxicity of microplastics and natural particles in the freshwater dipteran Chironomus riparius: Same same but different?

Microplastics (MP) are contaminants of emerging concern in aquatic ecosystems. While the number of studies is rapidly increasing, a comparison of the toxicity of MP and natural particulate matter is largely missing. In addition, research focusses on the impacts of hydrophobic chemicals sorbed to plastics. However, the interactive effects of MP and hydrophilic, dissolved chemicals remain largely unknown. Therefore, we conducted chronic toxicity studies with larvae of the freshwater dipteran Chironomus riparius exposed to unplasticised polyvinyl chloride MP (PVC-MP) as well as kaolin and diatomite as reference materials for 28 days. In addition, we investigated the effects of particles in combination with the neonicotinoid imidacloprid in a multiple-stressor experiment. High concentrations of kaolin positively affected the chironomids. In contrast, exposure to diatomite and PVC-MP reduced the emergence and mass of C. riparius. Likewise, the toxicity of imidacloprid was enhanced in the presence of PVC-MP and slightly decreased in the co-exposure with kaolin. Overall, parallel experiments and chemical analysis indicate that the toxicity of PVC-MP was not caused by leached or sorbed chemicals. Our study demonstrates that PVC-MP induce more severe effects than both natural particulate materials. However, the latter are not benign per se, as the case of diatomite highlights. Considering the high, environmentally irrelevant concentrations needed to induce adverse effects, C. riparius is insensitive to exposures to PVC-MP.

Microplastics in the Bay of Biscay: An overview

Microplastics (MPs) are an environmental problem of growing concern, and several studies have defined the Bay of Biscay (BoB) as a marine litter accumulation area. To address the abundance of MPs in this region, a critical overview is presented compiling the research performed to date on the different water bodies, sediments and biota. The comparative assessment highlights high spatial and temporal variability in MP distribution. MPs appear in at least 50% of the samples in waters and sediments. Polypropylene, polyethylene, polyester and polystyrene are the most frequent polymers, with a significant predominance of fragments and fibres. The BoB can be considered a region with medium concentration of MPs. However, monitoring programmes are needed to compile data over time and thus evaluate the historical trends of MP pollution. The difficulty of comparing studies is highlighted, due to the use of different methodologies. Hence, the harmonisation of monitoring methods is urgently required.

Microplastic accumulation in benthic invertebrates in Terra Nova Bay (Ross Sea, Antarctica)

Microplastic contamination of the benthic invertebrate fauna in Terra Nova Bay (Ross Sea, Antarctica) was determined. Twelve macrobenthic species, characterized by different feeding strategies, were selected at 3 sampling sites at increasing distance from the Italian Scientific Base (Mario Zucchelli, Camp Icarus, Adelie Cove). The 83% of the analyzed macrobenthic species contained microplastics (0.01-3.29 items mg^-1). The size of the particles, measured by Feret diameter, ranged from 33 to 1000 µm with the highest relative abundance between 50 and 100 µm. Filter-feeders and grazers displayed values of microplastic contamination from 3 to 5 times higher than omnivores and predators, leading to the hypothesis that there is no evident bioaccumulation through the food web. The prevalent polymers identified by micro-FTIR were nylon (86%) and polyethylene (5%); other polymers identified in Antarctic benthos were polytetrafluoroethylene, polyoxymethylene, phenolic resin, polypropylene, polystyrene resin and XT polymer.

Types, occurrence and distribution of microplastics in sediments from the northern Tyrrhenian Sea

This is the first survey to investigate microplastic contamination in the Northern Tyrrhenian seafloor, along a 31 km-long transect from the port of Piombino (Tuscany) to the port of Portoferraio (Elba Island). Plastics extracted from 58 sediment samples were counted and identified by Fourier-transform infrared spectroscopy (FTIR). Plastic pollution occurred in sites closer to ports as well as in offshore stations. Microplastics (1-5 mm) accounted for over 80% of particles. For all samples, the dominant microplastic type was filaments, followed by fragments and films. Six polymers were identified: nylon, polyurethane, polyethylene, and polyethylene terephtalate were the most common. This part of the Tyrrhenian Sea is a busy shipping route connecting the mainland to the Elba Island, with thousands cargo and passenger ships passing by per year. Our data constitute a baseline for microplastic research in the Tyrrhenian seafloor.

Monitoring the occurrence of microplastic ingestion in Otariids along the Peruvian and Chilean coasts

Repeated reports of microplastic pollution in the marine pinniped diet have emerged in the last years. However, only few studies address the drivers of microplastics presence and the potential implications for monitoring microplastic pollution in the ocean. This study monitored their in the scats (N = 205) of four pinniped species/subspecies at five different locations in the southern Pacific Ocean (Peru and Chile). Samples from all rookeries contained microplastics, and overall, 68% of the examined scats contained fragments/fibers, mostly blue colored. We confirmed that 81.5% of the fragments/fibers were anthropogenic in origin , but only 30% were polymers. Scats from Juan Fernández Archipelago presented higher microplastic concentrations than continental rookeries. Also, the common diet in each location may influence the levels found in the samples. This study presents a useful non-invasive technique to track plastic pollution in top predator diets as bioindicators for future surveillance/management plans applied to different location.

Early Colonization of Weathered Polyethylene by Distinct Bacteria in Marine Coastal Seawater

Plastic debris in aquatic environments is rapidly colonized by a diverse community of microorganisms, often referred to as the "Plastisphere." Given that common plastics are derived from fossil fuels, one would expect that Plastispheres should be enriched with obligate hydrocarbon-degrading bacteria (OHCB). So far, though, different polymer types do not seem to exert a strong effect on determining the composition of the Plastisphere, and putative biodegrading bacteria are only found as rare taxa within these biofilms. Here, we show through 16S rRNA gene sequencing that the enrichment of a prominent OHCB member on weathered and non-weathered polyethylene only occurred at early stages of colonization (i.e., after 2 days of incubation in coastal marine water; 5.8% and 3.7% of relative abundance, respectively, vs. 0.6% on glass controls). As biofilms matured, these bacteria decreased in relative abundance on all materials (< 0.3% after 9 days). Apart from OHCB, weathered polyethylene strongly enriched for other distinct organisms during early stages of colonization, such as a specific member of the Roseobacter group and a member of the genus Aestuariibacter (median 26.9% and 1.8% of the community, respectively), possibly as a consequence of the availability of short-oxidized chains generated from weathering. Our results demonstrate that Plastispheres can vary in accordance with the weathering state of the material and that very early colonizing communities are enriched with taxa that can potentially degrade hydrocarbons. Given the lack of persistent enrichment and overall community convergence between materials over time, common non-hydrolysable polymers might not serve as an important source of carbon for mature Plastispheres once the labile substrates generated from weathering have been depleted.

Micro- and nanoplastic toxicity on aquatic life: Determining factors

Plastic pollution has become a major environmental concern due to its omnipresence and degradation to smaller particles. The potential toxicological effects of micro- and nanoplastic on biota have been investigated in a growing number of exposure studies. We have performed a comprehensive review of the main determining factors for plastic particle toxicity in the relevant exposure systems, from publications until including the year 2018. For a focused scope, effects of additives or other pollutants accumulated by the plastic particles are not included. In summary, current literature suggests that plastic particle toxicity depends on concentration, particle size, exposure time, particle condition, shape and polymer type. Furthermore, contaminant background, food availability, species, developmental stage and sex have major influence on the outcome of plastic particles exposures. Frequently reported effects were on body and population growth, energy metabolism, feeding, movement activity, physiological stress, oxidative stress, inflammation, the immune system, hormonal regulation, aberrant development, cell death, general toxicity and altered lipid metabolism. Several times reported were increased growth and food consumption, neuro-, liver- or kidney pathology and intestinal damage. Photosynthesis disruption was reported in studies investigating effects on phytoplankton. For the currently unquantified plastic particles below 10 μm, more toxic effects were reported in all aquatic life, as compared to plastic particles of larger size.

Microplastics in sea ice and seawater beneath ice floes from the Arctic Ocean

Within the past decade, an alarm was raised about microplastics in the remote and seemingly pristine Arctic Ocean. To gain further insight about the issue, microplastic abundance, distribution and composition in sea ice cores (n = 25) and waters underlying ice floes (n = 22) were assessed in the Arctic Central Basin (ACB). Potential microplastics were visually isolated and subsequently analysed using Fourier Transform Infrared (FT-IR) Spectroscopy. Microplastic abundance in surface waters underlying ice floes (0–18 particles m⁻³) were orders of magnitude lower than microplastic concentrations in sea ice cores (2–17 particles L⁻¹). No consistent pattern was apparent in the vertical distribution of microplastics within sea ice cores. Backward drift trajectories estimated that cores possibly originated from the Siberian shelves, western Arctic and central Arctic. Knowledge about microplastics in environmental compartments of the Arctic Ocean is important in assessing the potential threats posed by microplastics to polar organisms.

Distribution of microplastics in surface water and sediments of Qin river in Beibu Gulf, China

As a series of pollutants, microplastics have recently attracted widespread attention worldwide. In this study, different surface water and sediment samples were collected at 12 sampling sites along the urban section of Qin River in Guangxi Province, China. Water samples were collected using plankton nets with two different pore sizes (75 μm and 300 μm) and Teflon pump system with 25 μm mesh screen. The results showed that there was no significant difference in the abundance, particle size, and type of microplastics (F = 0.302, P = 0.588) between the two plankton nets, but the microplastic abundance in the samples collected by the Teflon pump was significantly higher (F = 9.12, P = 0.001), especially for microplastic fibers (F = 9.525, P = 0.001). Compared with the plankton net sampling method, the Teflon pump sampling had a smaller sample volume, resulting in a higher estimate of microplastic abundance in the water column. The microplastic abundance in the sediments was 0-97 items·kg^-1 dry weight. PE and PP were the main types of microplastics in Qin River, accounting for 67.2% and 72.3% in the water column and sediments, respectively. The microplastics in the water column and sediments were dominated by large-sized particles in the range of 1-5 mm. The sources of microplastic pollution in Qin River may be affected by many factors, including population density, industrial structure, and aquaculture activities. However, aquaculture activities were generally the main source of microplastic pollution in Qin River estuary. Wastewater treatment plants (WWTPs) could effectively decrease the microplastic abundance in urban sewage, reducing the impact of urban sewage discharge on microplastic accumulation in Qin River.

Seasonal microplastics variation in nival and pluvial stretches of the Rhine River - From the Swiss catchment towards the North Sea

Rivers are pivotal carriers of microplastic (MP) towards the oceans. Investigative data on MP pollution in rivers at specific timepoints is continuously compiled. However, such snapshot data can only roughly indicate the long-term extent of contamination and particle fluxes; modelling studies informed by this limited data are prone to large uncertainties. The present study sought to narrow this knowledge gap by examining the differences in MP concentrations, loads and compositions at three nival tributaries and the Rhine River in Basel, Switzerland, as well as two downstream pluvial Lower Rhine River locations in Germany over four seasons throughout 2016-2017. MP concentrations (>0.3 mm) correlated positively with average water discharge and catchment size of the evaluated stream locations and MP concentrations were significantly higher at the downstream pluvial than upstream nival sites. There was no coherent pattern in MP concentration fluctuations between seasons across the six sites investigated, and no correlation with recent precipitation. These findings suggest that temporal variations in MP fluxes towards the North Sea through the year are dominated by the different discharge regimes along the river course. This study also corroborates theoretical models that predict the highest MP loads move downstream the Rhine River during the European winter months.

Microplastics and seafood: lower trophic organisms at highest risk of contamination

Microplastic debris is a prevalent global pollutant that poses a risk to marine organisms and ecological processes. It is also suspected to pose a risk to marine food security; however, these risks are currently poorly understood. In this review, we seek to understand the current knowledge pertaining to the contamination of commercially important fished and farmed marine organisms with microplastics, with the aim of answering the question "Does microplastic pollution pose a risk to marine food security?". A semi-systematic review of studies investigating the number of microplastics found in commercially important organisms of different trophic levels suggests that microplastics do not biomagnify, and that organisms at lower trophic levels are more likely to contaminated by microplastic pollution than apex predators. We address the factors that influence microplastic consumption and retention by organisms. This research has implications for food safety and highlights the risks of microplastics to fisheries and aquaculture, and identifies current knowledge gaps within this research field.

Analysis of microbeads in cosmetic products in the United Arab Emirates

The microparticle content of 37 common facial and body scrubs commercially available in the United Arab Emirates was analyzed. The chemical composition, ash content, physical characteristics, loading, particle size and shape of the microparticles were determined. Only 11 out of 37 products were found to have microplastic content. Many of the remaining products exhibited microparticles composed of microcrystalline cellulose and crushed walnut shells. Differential scanning calorimetry showed that microplastic products had softening points as low as 84 °C. Plastic microbeads of 2 products were found to fuse at 100 °C. The fusion altered the flotation characteristics of the microbeads of one product. Heat treatment of the product at 100 °C in the presence of silica gel led to entrainment of the silica and partial fragmentation of the beads upon cooling. This may be understood as one mechanism of fragmentation of a microplastic with a low softening point in the presence of hard soil particles under temperature cycling.

Atmospheric microplastic deposition in an urban environment and an evaluation of transport

Microplastics are a global environmental issue contaminating aquatic and terrestrial environments. They have been reported in atmospheric deposition, and indoor and outdoor air, raising concern for public health due to the potential for exposure. Moreover, the atmosphere presents a new vehicle for microplastics to enter the wider environment, yet our knowledge of the quantities, characteristics and pathways of airborne microplastics is sparse. Here we show microplastics in atmospheric deposition in a major population centre, central London. Microplastics were found in all samples, with deposition rates ranging from 575 to 1008 microplastics/m²/d. They were found in various shapes, of which fibrous microplastics accounted for the great majority (92%). Across all samples, 15 different petrochemical-based polymers were identified. Bivariate polar plots indicated dependency on wind, with different source areas for fibrous and non-fibrous airborne microplastics. This is the first evidence of airborne microplastics in London and confirms the need to include airborne pathways when consolidating microplastic impacts on the wider environment and human health.

Microplastic pollution in water and sediment in a textile industrial area

Microplastics pollution in the environment is closely determined by the surrounding industrial and human activities. In present study, we investigated microplastics in water and sediment samples collected from a textile industrial area in Shaoxing city, China. The abundance of microplastics varied from 2.1 to 71.0 items/L in surface water samples, and from 16.7 to 1323.3 items/kg (dw) in sediment samples. The polymer type was dominated by polyester both in water (95%) and sediment (79%) samples. The majority of the detected microplastics was predominantly colored fibers smaller than 1 mm in diameter. The high level of microplastic pollution detected in local freshwater and sediment environments was attributed to the production and trading activities of textile industries, for which severe regulations should be envisaged in the future to effectively reduce the local microplastic pollution.

Vertical distribution of microplastics in bay sediment reflecting effects of sedimentation dynamics and anthropogenic activities

Microplastics are ubiquitous in our environment, yet we have little knowledge on their accumulation profile and changing trend. In this study, we selected the semi-enclosed Jiaozhou Bay as the research area to study the vertical distribution characteristics of microplastic in the sediment and analyzed factors that might affect this distribution pattern. We found six different polymer types and the microplastic abundance ranged between 2.5 items/kg d.w.-27.5 items/kg d.w.. Microplastic abundance was very low in deep sediment and generally showed a decreasing trend from the surface down with some shifts at different depth at certain sites. Based on our data, the total microplastics in the sediment were estimated to reach 3.71 tons in Jiaozhou Bay. This study shows that the vertical microplastic abundance profile in the sediment can not only show the microplastics pollution level but also reflect environmental factors and anthropogenic impacts.

How climate change and eutrophication interact with microplastic pollution and sediment resuspension in shallow lakes: A review

Climate change and eutrophication are both critical environmental issues currently. Climate change induces more critical microplastic pollution and sediment resuspension in eutrophic lakes, and conversely the presence of microplastics and resuspension events would intensify these two environmental effects. Via evaluating the impacts of microplastics and sediment resuspension on climate change and eutrophication, it is favorable to provide recommendations for ecological protection and policy formulation in regard to the nutrient input as well as the production and utilization of plastic. In this review, we explore how climate change and eutrophication interact with microplastic pollution and sediment resuspension in shallow lakes, highlighting that both of the latter two play a significant role in the former two. Furthermore, future prospects are put forward on the further and deeper research on the global warming and eutrophication in shallow lakes with microplastic pollution.

Microplastic (1 and 5 μm) exposure disturbs lifespan and intestine function in the nematode Caenorhabditis elegans

As an emerging environmental pollutant, microplastics (MPs) are increasingly viewed as a serious health concern to terrestrial and aquatic ecosystems. However, previous toxicological studies examining MPs on freshwater and terrestrial organisms provide contradictory results, possibly due to few investigations at environmentally relevant concentrations. Here, the nematode Caenorhabditis elegans (C. elegans), a model organisms with both aquatic and terrestrial free-living forms, was employed to investigate the effects of 1 and 5 μm MPs (10⁷-10¹⁰ particles/m²) on the intake, lifespan, defecation rhythm, defecation-related neurons and transcriptional expression of related genes (skn-1, mkk-4, pmk-1, cpr-1 and itr-1). We demonstrated that the percentage of MP-contaminated nematodes increased with increasing exposure concentrations and duration. The lifespan of nematodes in the lower concentration exposure groups (2.4 × 10⁷ and 2.4 × 10⁸ particles/m²) decreased more prominently than that of higher concentration groups (2.4 × 10⁹ and 2.4 × 10¹⁰ particles/m²) after a 72-h exposure period. Concomitantly, expression of the skn-1 gene, involved in detoxification and lifespan regulation, was significantly altered at lower MP concentrations. Physiologically, the defecation rhythm after a 72-h exposure period was most strongly affected by 1 μm MPs at 2.4 × 10⁸ particles/m². The significant up-regulation of related genes by 1 μm MPs appears responsible for the shortened defecation interval. Results of this study identified a potential toxicity threat to C. elegans from exposure to MPs at environmentally relevant concentrations and provide novel evidence for MP risks to freshwater and terrestrial organisms. Capsule. After exposure to 1 and 5 μm MPs (10⁷-10¹⁰ particles/m²), the lifespan of C. elegans decreased more rapidly at lower concentrations.

Release of hazardous nanoplastic contaminants due to microplastics fragmentation under shear stress forces

The presence of nanoplastics in water has become a major environmental concern in the last decade however the knowledge on the origin and formation of these emerging contaminants is lacking due to analytical challenges in detection and quantification techniques. The release of nanoplastics due to the fragmentation of microplastics extracted from a facial scrub and the resulting toxicity on aquatic species are reported here for the first time. The daily use of 4 g of facial scrub could release up to 10¹¹ microplastics of 400 nm in size per litre of wastewater from household drains. Turbulences created by mixing or pumping induced the fragmentation of microplastics into nanoplastics smaller than 10 nm via a crack propagation and failure mechanism, increasing the number of particles in water by one order of magnitude. Compared to microplastics at a fixed concentration number of 6.8 × 10⁸ part./mL, the generated nanoplastics initiated the death of 54% more cells in zebrafish by passive ingestion via skin diffusion which therefore pose a real threat for aquatic living organisms. These results stress the need to reduce the release of nano/microplastics in the aquatic environment to prevent the contamination of all trophic levels.

Increased Temperature and Turbulence Alter the Effects of Leachates from Tire Particles on Fathead Minnow (Pimephales promelas)

Tire particles are of concern as a stressor due to the combination of their chemical constituents, high emission rates, and global distribution. Once in the environment, they will interact with physical parameters (e.g., UV, temperature). The interaction of chemical pollution with changing physical environmental parameters is often underestimated in ecotoxicology. Here, we investigate the role of temperature, mechanical stress (i.e., turbulence), UV, and CO₂ on the effects of tire leachates on fish. Two samples of tire particles were exposed to four different levels of each physical stressor. A toxicological assessment was performed with fathead minnow embryos assessing five end points (hatching success, time to hatch, length, deformities, and heart rate). Results showed that variations of temperature and mechanical stress affect the toxicological impact of tire leachates. Zn and/or polycyclic aromatic hydrocarbons (pyrene, phenanthrene, chrysene, benzo[a]pyrene, anthracene, naphthalene, fluoranthene, and benzo[ghi]perylene) were identified in the leachate and tire samples by Raman/surface-enhanced Raman spectroscopy and gas chromatography with mass spectroscopy, respectively.

Abundance and distribution of microplastics on sandy beaches of Lima, Peru

Microplastic pollution is a problem of global scale, posing a threat to marine biota. To determine the current state of microplastic pollution on four popular sandy beaches of the coast of Lima, Peru, a sampling campaign was carried out in both intertidal and supralittoral zones. Microplastic abundance, type, size, color and distribution were recorded. The overall microplastic abundance was of the same order of magnitude as previous data obtained in Peru. Foams were the most abundant (78.3%) microplastic type. Statistical analyses revealed significant differences between sites and zones. High variability of microplastic abundance was found among adjacent beaches and zones. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that all foams were identified as polystyrene. The present results revealed an alarming level of microplastics present on Peruvian sandy beaches, but information about the sources, local dynamics and impacts of microplastics in this region are scarce, and thus further research is needed.

Plastic debris accumulation in the seabed derived from coastal fish farming

In this study, we assessed plastic accumulation in marine sediments due to finfish aquaculture using floating net-pens. We studied plastic concentrations around three fish farms located at the Mediterranean coastline of Spain. The macroplastic categories and abundances were determined by video monitoring, detecting the majority of elements (78%), including ropes, nets and fibres, a basket trap and a cable tie, close to the facilities, which were not exclusively linked to fish farming but also to fishing activities. Concentrations of microplastics (<5 mm) ranged from 0 to 213 particles/kg dry weight sediment with higher values in sites directly under the influence of the fish farms. Most particles (27.8%) were within the size fraction from 1.1 to 2.0 mm and fibre was the most common shape with 62.2%. The Infrared spectroscopy analysis showed that PE and PP were the predominant types of polymers analysed. In addition, changes in the enthalpy of melting (ΔH_m (J/g)) and the degree of crystallinity indicate degradation of the microplastics analysed. This study shows that, in the studied fish farms, levels of microplastic pollution can be one order of magnitude lower compared to other areas suffering other anthropogenic pressures from the same or similar regions. Nevertheless, more research effort is needed to get concluding results.

Abundance, distribution patterns, and identification of microplastics in Brisbane River sediments, Australia

Plastic pollutants in aquatic ecosystems have received wide attention and research endeavours since early 1970s. However, in comparison to marine environments, the occurrence of microplastics in a tidal river system remains largely unknown, especially in river sediments. Sediment samples taken from twenty-two sampling points along Brisbane River over the four different seasons revealed relatively high concentrations of microplastics in river sediments, with abundance ranging from 0.18 to 129.20 mg kg^-1, or 10 to 520 items kg^-1. Unfortunately, varied methods and units used for reporting do not allow the accurate comparison between related studies. The spatial distributions of microplastics hotspots indicated that microplastics abundance is distance-dominated caused by flow velocities. Lower and higher concentrations of microplastics abundance mostly occurred in dry and wet seasons, respectively. Significant temporal variations of microplastics concentrations was observed in residential and commercial areas. Polyethylene (PE), polyamide (PA) and polypropylene (PP), were the three main polymer types found in the Brisbane River sediments. Other polymer types such as polyethylene terephthalate (PET) were also detected. The majority of the detected microplastic particles were found to be <3 mm. This study reveals the abundance, spatial and temporal distribution patterns, and characteristics of microplastic pollutants in Brisbane River sediments, and provides systematic data for further research on microplastics in estuarine environments worldwide.

Marine Microbial Assemblages on Microplastics: Diversity, Adaptation, and Role in Degradation

We have known for more than 45 years that microplastics in the ocean are carriers of microbially dominated assemblages. However, only recently has the role of microbial interactions with microplastics in marine ecosystems been investigated in detail. Research in this field has focused on three main areas: (a) the establishment of plastic-specific biofilms (the so-called plastisphere); (b) enrichment of pathogenic bacteria, particularly members of the genus Vibrio, coupled to a vector function of microplastics; and (c) the microbial degradation of microplastics in the marine environment. Nevertheless, the relationships between marine microorganisms and microplastics remain unclear. In this review, we deduce from the current literature, new comparative analyses, and considerations of microbial adaptation concerning plastic degradation that interactions between microorganisms and microplastic particles should have rather limited effects on the ocean ecosystems. The majority of microorganisms growing on microplastics seem to belong to opportunistic colonists that do not distinguish between natural and artificial surfaces. Thus, microplastics do not pose a higher risk than natural particles to higher life forms by potentially harboring pathogenic bacteria. On the other hand, microplastics in the ocean represent recalcitrant substances for microorganisms that are insufficient to support prokaryotic metabolism and will probably not be microbially degraded in any period of time relevant to human society. Because we cannot remove microplastics from the ocean, proactive action regarding research on plastic alternatives and strategies to prevent plastic entering the environment should be taken promptly.

Degradation of excavated polyethylene and polypropylene waste from landfill

In 2016, it was estimated that 7.4 million tonnes of plastic waste have been disposed in landfill in Europe. This waste represents an important opportunity for resource recovery through enhanced landfill mining consistent with recent Circular Economy initiatives. However, a recent review found a lack of data describing the degradation of excavated plastic waste and the potential impact on recycling products such as pyrolysis oil. In this study, the physicochemical characteristics of the main plastic types found in landfills and their implications for recovery and recycling were investigated using a combination of scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), attenuated total reflectance Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Loss of gloss was visually detected for the buried plastic waste samples (polyethylene (PE) and polypropylene (PP)) compared to fresh plastic samples. The SEM-EDS analysis further showed that oxygen was the main element related to the plastic surface alteration. The carbonyl index (CI) of plastic samples buried for >10 years was between 1.5 and 2 times higher than <10 years and fresh materials. Similarly, the degree crystallinity of the old samples (>10 years) was 2 times higher than the fresh and < 10 years samples. Based on these findings, tertiary recycling, such as pyrolysis, seems to be a convenient route for upcycling of recovered plastics from municipal solid waste landfills.

Microplastic contamination in Penaeid shrimp from the Northern Bay of Bengal

Microplastic pollution has received increased attention recently due to potential threat to marine biota and human health. This study reports microplastic (MP) content in brown shrimp (Metapenaeus monocerous) and tiger shrimp (Penaeus monodon) inhabiting in the shallow and offshore waters of the Northern Bay of Bengal, Bangladesh. Gastrointestinal tract (GT) of shrimps (n = 150) were examined for MPs following alkali digestion, microscopic observation and chemical analysis by micro-Fourier Transformed Infrared Spectroscope (μFTIR). A total of 33 and 39 MP items were found in P. monodon and M. monocerous, averaging 3.40 ± 1.23 and 3.87 ± 1.05 items/g GT, respectively. Among various shapes, types and colours of MP, filament (57-58%), fiber (32-57%) and black (48-51%) were dominant amongst the various particles identified. Tiger shrimp had high numbers (23 items) of larger size fractions of MPs (1-5 mm) but brown shrimp had high numbers (15 items) of smaller MPs (250-500 μm), and μ-FTIR data confirmed 13 particles of polyamide-6 and 6 particles of rayon polymers. These results provide a baseline of MP contamination in seafood from Bangladesh that should be useful for future monitoring efforts.

Superimposed microplastic pollution in a coastal metropolis

The mitigation of microplastic pollution in the environment calls for a better understanding of the sources and transportation, especially from land sources to the open ocean. We conducted a large-scale investigation of microplastic pollution across the Greater Melbourne Area and the Western Port area, Australia, spanning gradients of land-use from un-developed catchments in conservation areas to more heavily-developed areas. Microplastics were detected in 94% of water samples and 96% of sediment samples, with abundances ranging from 0.06 to 2.5 items/L in water and 0.9 to 298.1 items/kg in sediment. The variation of microplastic abundance in sediments was closely related to that of the overlying waters. Fiber was the most abundant (89.1% and 68.6% of microplastics in water and sediment respectively), and polyester was the dominant polymer in water and sediment. The size of more than 40% of all total microplastics observed was less than 1 mm. Both light and dense polymers of different shapes were more abundant in sediments than those in water, indicating that there is microplastic accumulation in sediments. The abundance of microplastics was higher near coastal cities than at less densely-populated inland areas. A spatial analysis of the data suggests that the abundance of microplastics increases downstream in rivers and accumulates in estuaries and the lentic reaches of these rivers. Correlation and redundancy analysis were used to explore the associations between microplastic pollution and different land-use types. More microplastics and polymer types were found at areas with large amounts of commercial, industrial and transport activities. Microplastic abundances were also correlated with mean particle size. Microplastic hotspots within a coastal metropolis might be caused by a combination of natural accumulation via hydrological dynamics and contribution from increasing anthropogenic influences. Our results strongly suggest that coastal metropolis superimposed on increasing microplastic levels in waterbodies from inland areas to the estuaries and open oceans.

On mechanical fragmentation of single-use plastics in the sea swash zone with different types of bottom sediments: Insights from laboratory experiments

Mechanical fragmentation of four commonly used plastics, from 2-cm squares or cubes to microplastics (MPs, <5 mm), is experimentally investigated using a rotating laboratory mixer mimicking the sea swash zone with natural beach sediments (large and small pebbles, granules, sand). Macro-samples were prepared from brittle not-buoyant PS (disposable plates), flexible thin film of LDPE (garbage bags), highly buoyant foamed PS (building insulation sheets), and hard buoyant PP (single-use beverage cups). With a great variety of behaviors of plastics while mixing, coarser sediments (pebbles) have higher fragmentation efficiency than sands (measured as the mass of generated MPs), disregarding sinking/floating or mechanical properties of the samples. It is confirmed that, under swash-like mixing with coarse sediments, the MPs tend to burry below the sediment surface. The obtained relationship between the mass of MPs and the number of items is similar to that for MPs floating at the ocean surface.

Occurrence and concentrations of chemical additives in plastic fragments on a beach on the island of Kauai, Hawaii

In the ocean, plastic debris containing chemical additives is fragmented into smaller pieces that can be ingested by a wide range of organisms, potentially exposing them to additives. However, the levels of additives retained in marine plastic fragments have rarely been assessed. In this study, 141 plastic fragments from a beach in Kauai were analyzed piece-by-piece for 12 compounds, including UV stabilizers and brominated flame retardants. UV stabilizers (UV-326, UV-328, UV-327, and BP-12) were found in 13% of "small" fragments (4-7 mm) with levels of up to 315 μg/g and in 33% of "large" fragments (15-80 mm) with levels of up to 1130 μg/g. This observation suggests that exhaustive leaching of additives does not occur during fragmentation and that significant levels of additives, comparable to those of the original products, can be retained in fragments of marine plastic, indicating their importance as a vector of chemical additive exposure.

Microplastic pollution in the sediment of Jagir Estuary, Surabaya City, Indonesia

This study was aimed to investigate the abundance and characteristics of microplastics (MP) in the sediment of Jagir estuary and Wonorejo coast, Surabaya, Indonesia. Sediment samples from 5 sites in the estuary and the adjacent coast were collected in replicates using Ekman dredge sampler. The MP particles were extracted using density separation method. Then the MP particles were counted and categorized according to shape, size, and color under a Zeiss Discovery V.12 stereomicroscope. Identification was done using Thermo Scientific Nicolet iS10 FTIR Spectrometer. The MP shapes comprised fiber (57%), film (36%), and fragment (7%). Abundance of the MP was highest in the Wonorejo coast sediment (590 particles/kg dry weight). The MP particles consisted of 68% large and 25% small sizes and comprised 56.7% polyester, 24.6% low-density polyethylene, and 18.8% polypropylene. The MP colors were 43% transparent, 21% black, 14% blue, 10% white, 8% red, and 4% yellow.

Retention of microplastics in sediments of urban and highway stormwater retention ponds

Urban and highway surfaces discharge polluted runoff during storm events. To mitigate environmental risks, stormwater retention ponds are commonly constructed to treat the runoff water. This study is the first to quantify the retention of microplastics in the sediments of such ponds. It applied state-of-art FTIR-methods to analyse the composition, size, shape, and mass of microplastics in the range 10-2000 μm. Seven ponds serving four land uses were investigated, and the results are related to catchment characteristics, sediment organic matter content, and hydraulic loading. We have not found a correlation between the microplastics abundance, polymer composition, size distribution and the land use in the catchment, as well as the sediment organic matter content. Both the highest (127,986 items kg^-1; 28,732 μg kg^-1) and the lowest (1511 items kg^-1; 115 μg kg^-1) accumulation of microplastics were found in the sediments of ponds serving industrial areas. There was, however, a correlation to the hydraulic loading of the ponds, where the sediments of the highest-loaded ponds held the most microplastics. This study shows that sediments in stormwater retention ponds can trap some of the microplastics and prevent them from being transported downstream. These systems need to be considered when assessing the fate of microplastics from urban and highway areas.

Distribution characteristics of microplastics in Zhubi Reef from South China Sea

As a new type of emerging pollutant in the ocean, microplastics have received global attention in recent years. Considering the increasing amount of human activities around the South China Sea, it is important to determine the current status of microplastic pollution in this region. In this study, we analyzed the abundance and distribution of microplastics at Zhubi Reef in the South China Sea. Microplastic abundance ranged from 1400 to 8100 items/m³ of surface water, which was much higher than the values reported from other ocean areas. About 80% of the microplastics were smaller than 0.5 mm in size. Fibers and pellets comprised the most common microplastic types. The dominant microplastics were transparent or blue in color. The main polymer types were polypropylene (25%) and polyamide (18%). In general, our results revealed Zhubi Reef was contaminated with microplastics, which were likely derived from the intensive fisheries in the area and emissions from coastal cities. This study also provides baseline data that are useful for additional studies of microplastics in the South China Sea.