Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary ...responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions.
•Suspended microplastic were investigated within three densely populated/developed urban estuaries, China.•Economical structures may contribute to the abundances of microplastic particles within the studied estuaries.•Typhoon Soulik didn't influence microplastic densities in the water column of Minjiang Estuary.•Microplastics (<5 mm in diameter) dominated more than 90% of the total plastic by number.
Suspended microplastics (MPs) levels were quantified within three urban estuaries, China. MPs densities were consistent with the urban economical structure, and that in Minjiang were unaffected by Typhoon.
•The quantity and composition of suspended microplastics are reported for the first time in China.•Microplastics (0.5–5mm) constituted more than 90% of total plastics by number of ...items.•Microplastics concentrations were spatially variable in the Yangtze Estuary.•Large rivers are contributed to the high MP abundances in the adjacent marine environment.•The most abundant plastics were fibres, while plastic spherules were rarely found.
Levels of microplastics (MPs) in China are completely unknown. This study characterizes suspended MPs quantitatively and qualitatively for the Yangtze Estuary and East China Sea. MPs were extracted via a floatation method. MPs were counted and categorized according to shape and size under a stereomicroscope. The MP densities were 4137.3±2461.5 and 0.167±0.138n/m3, respectively, in the estuarine and the sea samples. Plastic abundances varied significantly in the estuary. Higher densities in three sea trawls confirmed that rivers were the important sources of MP to the marine environment. Plastic particles (>5mm) were observed with a maximum size of 12.46mm, but MPs (0.5–5mm) constituted more than 90% by number of items. The most frequent geometries were fibres, followed by granules and films. Plastic spherules occurred sparsely. Transparent and coloured plastics comprised the majority of the particles. This study provides clues in understanding the fate and potential sources of MPs.
Microplastics, which are plastic debris with a particle diameter of less than 5 mm, have attracted growing attention in recent years. Its widespread distributions in a variety of habitats have urged ...scientists to understand deeper regarding their potential impact on the marine living resources. Most studies on microplastics hitherto are focused on the marine environment, and research on risk assessment methodology is still limited. To understand the distribution of microplastics in urban rivers, this study investigated river sediments in Shanghai, the largest urban area in China. Seven sites were sampled to ensure maximum coverage of the city's central districts, and a tidal flat was also included to compare with river samples. Density separation, microscopic inspection and μ-FT-IR analysis were conducted to analyze the characteristics of microplastics and the type of polymers. The average abundance of microplastics in six river sediment samples was 802 items per kilogram of dry weight. The abundance in rivers was one to two orders of magnitude higher than in the tidal flat. White microplastic spheres were most commonly distributed in river sediments. Seven types of microplastics were identified, of which polypropylene was the most prevailing polymers presented. The study then conducted risk assessment of microplastics in sediments based on the observed results, and proposed a framework of environmental risk assessment. After reviewing waste disposal related legislation and regulations in China, this study conclude that in situ data and legitimate estimations should be incorporated as part of the practice when developing environmental policies aiming to tackle microplastic pollution.
Display omitted
•Rivers in urban areas suffered from more human activities than tidal flats.•Microplastic abundance in urban rivers was one to two orders of magnitude higher than in the tidal flat.•White spherical microplastics were widely distributed in urban river sediments.•Risk assessment was conducted, and a framework for environmental risk assessment for microplastics was proposed.•Waste disposal related legislation and regulations in China were summarized.
Microplastic abundance in rivers was one to two orders of magnitude higher than in the tidal flat, and a framework of risk assessment was proposed.
Plastic debris and marine microplastics are being discharged into the ocean at an alarming scale and have been observed throughout the marine environment. Here we report microplastic in sediments of ...the Challenger Deep, the deepest known region on the planet, abyssal plains and hadal trenches located in the Pacific Ocean (4900 m–10,890 m). Microplastic abundance reached 71.1 items per kg dry weight sediment. That high concentrations are found at such remote depths, knowing the very slow sinking speed of microplastics, suggests that supporting mechanisms must be at-play. We discuss cascading processes that transport microplastics on their journey from land and oceanic gyres through intermediate waters to the deepest corners of the ocean. We propose that hadal trenches will be the ultimate sink for a significant proportion of the microplastics disposed in the ocean. The build-up of microplastics in hadal trenches could have large consequences for fragile deep-sea ecosystems.
Display omitted
•Microplastics were prevalent in the deepest parts on earth, the hadal trenches.•Microplastics in hadal trenches outnumbered previous reports from the deep sea.•Hadal trenches will be the major depositories and ultimate sink for microplastics.•Cascading processes that transport microplastics from land to the deep are at play.•Trophic transfer, biological interaction and physical processes play key roles.
Although atmospheric microplastics have been found to be ubiquitous even on untraversed mountains and have potential impacts on human health, little information concerning their sampling methodology ...and transport is currently available. Until a realistic quantification of suspended atmospheric microplastics (SAMPs) is obtained, however, any potential health risk assessment for this pollutant will be open to criticism for using an ambiguous dataset. To address this knowledge gap, in May 2019 a trial experiment was performed to explore the potential relationship between sampling volume and SAMP abundance. A significant logarithmic regression between SAMP abundance and the sampling volume of filtrated air was found and the sufficient volume of filtrated air for accurate SAMP quantification was recommended. Investigation results indicated that fibrous and fragment-shaped SAMPs comprised 91% of all of the identified synthetic particles. Interestingly, for the first time, plastic microbeads were also observed in the collected air, constituting 9% of the all of the SAMPs by quantity. Spectral analysis revealed that these SAMPs consisted of polyethylene terephthalate (PET), epoxy resin (EP), polyethylene (PE), alkyd resin (ALK), rayon (RY), polypropylene (PP), polyamide (PA), and polystyrene (PS). PET, EP, PE, and ALK constituted the majority (90%) of all of the polymer types, with quantitative percentages of 51%, 19%, 12%, and 8%, respectively. Based on our numerical modeling simulation, the approximate transport flux of SAMPs during June in Shanghai was estimated, ranging from 9.94 × 104 n/(m·d) to 6.52 × 105 n/(m·d), with a mean of 3.00 ± 1.58 × 105 n/(m·d). The goal of our study was to provide an essential methodological aid for the accurate determination of SAMPs in the environment and a better understanding of terrestrial microplastic transport in megacities.
•A stable sampling methodology for SAMPs was presented and verified.•The proper volume of filtrated air for accurate SAMP quantification was recommended.•The transport flux of SAMPs was roughly estimated in the megacity of Shanghai.
Although atmospheric transport and deposition could be an important pathway of terrestrial pollutants to the ocean, little information concerning the presence and distribution of these suspended ...atmospheric microplastics in marine air is available. We investigated, for the first time, the occurrence and distribution of suspended atmospheric microplastics (SAMPs) in the west Pacific Ocean. In this study, the spatial distribution, morphological appearance, and chemical composition of suspended atmospheric microplastics were studied through continuous sampling during a cruise. SAMPs abundance ranged from 0 to 1.37 n/m3, the median of 0.01 n/m3. Fiber, fragment, and granule SAMPs quantitively constituted 60%, 31%, and 8% of all MPs, respectively. Interestingly, plastic microbeads with numerical proportion of 5% were also observed. A high suspended atmospheric microplastics abundance was found in the coastal area (0.13 ± 0.24 n/m3), while there was less amount detected in the pelagic area (0.01 ± 0.01 n/m3). The amount of suspended atmospheric microplastics collected during the daytime (0.45 ± 0.46 n/m3) was twice the amount collected at night (0.22 ± 0.19 n/m3), on average. Our observations provide field-based evidence that suspended atmospheric microplastics are an important source of microplastics pollution in the ocean, especially the pollution caused by textile microfibers.
Plastic trash is common in oceans. Terrestrial and marine ecosystem interactions occur in the intertidal zone where accumulation of plastic frequently occurs. However, knowledge of the ...plastic-associated microbial community (the plastisphere) in the intertidal zone is scanty. We used high-throughput sequencing to profile the bacterial communities attached to microplastic samples from intertidal locations around the Yangtze estuary in China. The structure and composition of plastisphere communities varied significantly among the locations. We found the taxonomic composition on microplastic samples was related to their sedimentary and aquatic origins. Correlation network analysis was used to identify keystone bacterial genera (e.g. Rhodobacterales, Sphingomonadales and Rhizobiales), which represented important microbial associations within the plastisphere community. Other species (i.e. potential pathogens) were considered as hitchhikers in the plastic attached microbial communities. Metabolic pathway analysis suggested adaptations of these bacterial assemblages to the plastic surface-colonization lifestyle. These adaptations included reduced “cell motility” and greater “xenobiotics biodegradation and metabolism.” The findings illustrate the diverse microbial assemblages that occur on microplastic and increase our understanding of plastisphere ecology.
Display omitted
•The information of plastic-associated microbial community in the intertidal zone is scanty.•Microbial communities attached plastics discriminates among three intertidal ecosystems around the Yangtze estuary, China.•Keystone species were Alphaproteobacteria, Gammaproteobacteria, Flavobacteriia, Acidobacteria and Cyanobacteria.•Putatively pathogenic species acts as hitchhikers on microplastic particles.
Microplastics are plastics that measure less than 5 mm in diameter. They enter the marine environment as primary sources directly from industrial uses, as well as secondary sources resulting from the ...degradation of large plastic debris. To improve the knowledge of microplastic pollution in China, we investigated samples from 53 estuarine sediment locations collected with a box corer within the Changjiang Estuary. Microplastics (<5 mm) were extracted from sediments by density separation, after which they were observed under a microscope and categorized according to shape, color and size. Identification was carried out using Micro-Fourier-Transform Infrared Spectroscopy (μ-FT-IR).
The abundance of microplastics in the Changjiang Estuary was mapped. The mean concentration was 121 ± 9 items per kg of dry weight, varying from 20 to 340 items per kg of dry weight. It was found that the concentration of microplastics was the highest on the southeast coast of Shanghai. The distribution pattern of microplastics may be affected by the Changjiang diluted water in summer. All of the microplastics collected were categorized according to shape, color and size. Among which fiber (93%), transparent (42%) and small microplastics (<1 mm) (58%) were the most abundant types. No clear correlation between microplastics and the finer sediment fraction was found. Rayon, polyester, and acrylic were the most abundant types of microplastics identified, indicating that the main source of microplastics in the Changjiang Estuary was from washing clothes (the primary source). It is possible to compare microplastic abundance in this study with the results of other related studies using the same quantification method. The identification of microplastics raises the awareness of microplastic pollution from drainage systems. The prevalence of microplastic pollution calls for monitoring microplastics at a national scale on a regular basis.
Display omitted
•Microplastic concentration varied from 20 to 340 items/kg dry weight in the sediments of the Changjiang Estuary.•The average concentration was 121 items/kg dry weight.•Fiber, transparent and small microplastics (<1 mm) were the most abundant types.•Rayon, polyester and acrylic were the most abundant types according to identification results.•The source of microplastics in sediments of the Changjiang Estuary may be from washing clothes.
Microplastic concentration in sediments of the Changjiang Estuary varied from 20 to 340 items per kg of dry weight.
Display omitted
•Sunlight can remove microplastics from the sea surface.•The type of plastic influences how rapidly microplastics photo-degrade.•Microplastics dissolve at the sea surface due to ...sunlight-driven photochemistry.•Dissolved organic carbon is produced as microplastics photo-dissolve in sunlight.•Photo-produced dissolved organic carbon impacts marine bacteria.
Trillions of plastic fragments are afloat at sea, yet they represent only 1–2% of the plastics entering the ocean annually. The fate of the missing plastic and its impact on marine life remains largely unknown. To address these unknowns, we irradiated post-consumer microplastics (polyethylene, PE; polypropylene, PP; and expanded polystyrene, EPS), standard PE, and plastic-fragments collected from the surface waters of the North Pacific Gyre under a solar simulator. We report that simulated sunlight can remove plastics from the sea surface. Simulated sunlight also fragmented, oxidized, and altered the color of the irradiated polymers. Dissolved organic carbon (DOC) is identified as a major byproduct of sunlight-driven plastic photodegradation. Rates of removal depended upon polymer chemistry with EPS degrading more rapidly than PP, and PE being the most photo-resistant polymer studied. The DOC released as most plastics photodegraded was readily utilized by marine bacteria. However, one sample of PE microplastics released organics or co-leachates that inhibited microbial growth. Thus, although sunlight may remove plastics from the ocean’s surface, leachates formed during plastic photodegradation may have mixed impacts on ocean microbes and the food webs they support.
The role of rivers as a major transport pathway for all sizes of plastic debris into the ocean is widely recognized. Global modelling studies ranked the Changjiang River as the largest contributor of ...plastic waste to the marine environment, but these estimates were based on insufficient empirical data. To better understand the role of rivers in delivering terrestrial plastic debris to the ocean, the spatial and temporal patterns of microplastics (MP) in the Changjiang Estuary (CE) and the East China Sea (ECS) were studied based on surface water samples in February, May, and July 2017. A total of 3225 MP (60–5000 μm) were identified by Fourier-transform infrared (FTIR) spectrometry. MP abundance in July was higher than in February and May due to higher river discharge. Density stratification in CE significantly influenced the surface MP abundances. A temporal accumulation zone within the river-sea interface for plastics was indicated by stations with apparently higher abundances in the river plume. Fibers were the most common MP (>80%) over three months. Small MP (<1000 μm) composed 75.0% of the total plastics on average. The average mass of MP was 0.000033 g/particle, which was two orders of magnitude lower than the empirical mass in literature. Without considering tidal effects, we estimate 16–20 trillion MP particles, weighing 537.6–905.9 tons, entered the sea through the surface water layer of the Changjiang River in 2017. These findings of this study provide reliable information on MP waste in a large river, which should be considered in further studies for estimating the riverine plastic loads.
Display omitted
•MP abundance and size exhibited distinct seasonality in the Changjiang Estuary.•A ‘Patchiness’ in distribution of MP were observed in the Changjiang River plume.•The water density stratification impacted suspended microplastic abundances.•MP in our study averagely weighed 0.000033 g.•The annually MP load in the top layer of the Changjiang River is 537.6–905.9 tons.
PDF
