Microplastics in freshwater: A global review of factors affecting spatial and temporal variations.
Talbot Rebecca,Chang Heejun
Environmental pollution (Barking, Essex : 1987)
Microplastics are a pollutant of growing concern, capable of harming aquatic organisms and entering the food web. While freshwater microplastic research has expanded in recent years, much remains unknown regarding the sources and delivery pathways of microplastics in these environments. This review aims to address the scientific literature regarding the spatial and temporal factors affecting global freshwater microplastic distributions and abundances. A total of 75 papers, published through June 2021 and containing an earliest publication date of October 2014, was identified by a Web of Science database search. Microplastic spatial distributions are heavily influenced by anthropogenic factors, with higher concentrations reported in regions characterized by urban land cover, high population density, and wastewater treatment plant effluent. Spatial distributions may also be affected by physical watershed characteristics such as slope and elevation (positive and negative correlations with microplastic concentrations, respectively), although few studies address these factors. Temporal variables of influence include precipitation and stormwater runoff (positive correlations) and water flow/discharge (negative correlations). Despite these overarching trends, variations in study results may be due to differing scales or contributing area delineations. Thus, more rigorous and standardized spatial analytical methods are needed. Future research could simultaneously evaluate both spatial and temporal factors and incorporate finer temporal resolutions into sampling campaigns.
10.1016/j.envpol.2021.118393
Microplastics as a vehicle of heavy metals in aquatic environments: A review of adsorption factors, mechanisms, and biological effects.
Liu Si,Huang JinHui,Zhang Wei,Shi LiXiu,Yi KaiXin,Yu HanBo,Zhang ChenYu,Li SuZhou,Li JiaoNi
Journal of environmental management
Microplastics (MPs) have recently attracted much attention due to their widespread distribution in the aquatic environment. Microplastics can act as a vector of heavy metals in the aquatic environment, causing a potential threat to aquatic organisms and human health. This review mainly summarized the occurrence of microplastics in the aquatic environment and their interaction with heavy metals. Then, we considered the adsorption mechanisms of MPs and heavy metals, and further critically discussed the effects of microplastics properties and environmental factors (e.g., pH, DOM, and salinity) on the adsorption of heavy metals. Finally, the potential risks of combined exposure of MPs and heavy metals to aquatic biota were briefly evaluated. This work aims to provide a theoretical summary of the interaction between MPs and heavy metals, and is expected to serve as a reference for the accurate assessment of their potential risks in future studies.
10.1016/j.jenvman.2021.113995
New insights on aging mechanism of microplastics using PARAFAC analysis: Impact on 4-nitrophenol removal via Statistical Physics Interpretation.
Priyanka M,Saravanakumar M P
The Science of the total environment
The aging effects of Polyethylene terephthalate (PET) microplastics were studied under Fenton process and Seawater. This research work mainly focuses on the aging mechanism of PET microplastics under two different conditions and their effect of aging on the adsorption of organic contaminants. The results of optical microscopic images, Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman Spectroscopy, carbonyl, carboxyl index, X-ray powder diffraction (XRD) and dissolved organic carbon (DOC) help to understand the aging mechanism of PET microplastics. Parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy (2D-COS) were performed using 3D Excitation-Emission Matrix (3D-EEM) to understand the possible dissolved organic matter released during the Fenton process and seawater. The release of protein/phenol like components was observed in seawater whereas humic acid-like component was noted in the Fenton process. Later, the aged PET microplastics were tested for their adsorption capacity towards 4-nitrophenol at three different temperatures (15, 30 and 45 °C). The adsorption capacity of aged microplastics was found to be higher than the normal PET microplastics for all three different temperatures. Hydrogen bonding, n-pi interaction performed a significant role than pi-pi and hydrophobic interaction in the adsorption mechanism. A double layer with double energy model was found to be the best fit in the adsorption processes. The calculated adsorption energies (ΔE, ΔE) from the statistical physics modeling also confirms the physisorption mechanism. The above experimental results help to understand the behavior of microplastics at different aging period and how it acts as a carrier for pollutant in the marine environment.
10.1016/j.scitotenv.2021.150819
A first assessment of marine meso-litter and microplastics on beaches: Where does Mauritius stand?
Mattan-Moorgawa Sushma,Chockalingum Jemina,Appadoo Chandani
Marine pollution bulletin
Marine litter is a major global concern that is threatening marine ecosystems. This study assessed the meso-litter and microplastics density around Mauritius Island, South West Indian Ocean (SWIO) region. WIOMSA guidelines were used for meso-litter and microplastics sampling from October to December 2019 at 12 sites. A total of 1095 meso-litter items (weighing 1250 g) was sampled. Plastics were the most abundant litter category. 'Shoreline and recreational activities' were the main meso-litter source. Microplastics density was highest at the vegetation line (VL) zone. Fragments, mostly blue-coloured, were the most encountered type of microplastics, and polyethylene was the most prevalent polymer type. This study provides important baseline data which can be used by relevant authorities for more effective waste management strategies and awareness campaigns that will help further mitigate the marine litter problem in Mauritius, and to check the effectiveness of management measures in place.
10.1016/j.marpolbul.2021.112941
Bioavailability quantification and uptake mechanisms of pyrene associated with different-sized microplastics to Daphnia magna.
Lin Hui,Yuan Yinqiu,Jiang Xiaoman,Zou Jian-Ping,Xia Xinghui,Luo Shenglian
The Science of the total environment
Microplastics (MPs) are the significant environmental factor for bioavailability of hydrophobic organic contaminants (HOCs) in aquatic environments. Nevertheless, the bioavailability of microplastic-associated HOCs remains unclear. In this research, the freely dissolved pyrene concentrations were kept stable with passive dosing devices, and the pyrene content in D. magna tissues as well as D. magna immobilization were analyzed to quantify bioavailability of pyrene (a representative HOC) associated with naturally-aged polystyrene (PS) MPs. Furthermore, the uptake mechanisms of pyrene associated with MPs of different sizes were explored by investigating the distribution of MPs in D. magna tissues with scanning electron microscopy. Especially, a new schematic model of bioavailability process was established. The results demonstrated that a part of pyrene associated with 0-1.5 μm MPs could directly cross cell membrane through endocytosis from intestine and exposure solutions to D. magna tissues except the 10-60 and 60-230 μm MPs. The bioavailability of microplastic-associated pyrene was ordered as 0-1.5 μm (20.0-21.6%) > 10-60 μm (10.7-13.8%) > 60-230 μm MPs (6.0-9.8%), which were essentially resulted from the difference in uptake mechanisms of pyrene associated with MPs of different sizes. This work suggests that the bioavailability of microplastic-associated HOCs should be considered when assessing water quality and environmental risk of HOCs in natural waters.
10.1016/j.scitotenv.2021.149201
Polystyrene microplastics increase estrogenic effects of 17α-ethynylestradiol on male marine medaka (Oryzias melastigma).
Wang Jun,Li Xuan,Gao Ming,Li Xuefu,Zhao Lingchao,Ru Shaoguo
Chemosphere
Microplastics (MPs) and endocrine disrupting chemicals are ubiquitous pollutants in marine environments, but their combined ecological risk is unclear. This study exposed male marine medaka (Oryzias melastigma) to 10 ng/L 17α-ethynylestradiol (EE) alone or EE plus 2, 20, and 200 μg/L polystyrene MPs for 28 days to investigate the impacts of MPs on the reproductive disruption of EE. The results showed that 10 ng/L EE alone did not affect biometric parameters, while co-exposure to EE and 20, 200 μg/L MPs suppressed the growth and decreased gonadosomatic and hepatosomatic indices. Compared to EE alone, EE plus MPs exposure significantly increased plasma 17β-estradiol (E) levels in a dose-dependent manner, and co-exposure to EE and 20, 200 μg/L MPs significantly increased the ratios of E/testosterone (T). Moreover, EE plus MPs exposure elevated the transcription levels of estrogen biomarker genes vitellogenin and choriogenin, and estrogen receptor (ERα and ERβ). Morphological analysis also showed that co-exposure to EE and MPs induced more severe damage to the testes and livers, indicating that MPs increased the toxicity of EE. The actual EE concentrations in the solution increased with the exposure concentrations of MPs, suggesting that MPs changed the fate and behavior of EE in the seawater. These findings demonstrate that MPs could increase the estrogenic effects of EE on marine fish, suggesting that the combined health risk of MPs and endocrine disrupting chemicals on marine organisms should be paid great attention.
10.1016/j.chemosphere.2021.132312
Size effects of polystyrene microplastics on the accumulation and toxicity of (semi-)metals in earthworms.
Xu Guanghui,Yang Yang,Yu Yong
Environmental pollution (Barking, Essex : 1987)
Microplastics (MPs) are plastic fragments less than 5 mm, which may have adverse impacts on organisms. In this study, we investigated the impacts and mechanisms of polystyrene MPs (10 μm and 100 μm) and nanoplastics (NPs, 100 nm) with different concentrations (10 mg/kg and 100 mg/kg) in soil on the uptake of metal Cd and semi-metal As in earthworms, Eisenia fetida. MPs facilitated the accumulation of (semi-)metals via damaging the integrity of earthworm intestine, and earthworms accumulated more (semi-)metals in MP treatment groups than NP treatment groups, especially in group of 100 mg/kg of 10 μm MP with concentrations of 1.13 mg/kg and 32.7 mg/kg of Cd and As, respectively. Higher genotoxicity to earthworms was observed for MPs than NPs. Antioxidant enzymes activity and their mRNA gene relative expression levels indicated that MPs with high concentration induced severer damage to earthworms, thus resulting in the increased accumulation of (semi-)metals by earthworms. In addition, proteomic and metabolomic analysis revealed that MPs (100 ppm of 10 μm) disturbed the earthworm immune and metabolic systems, resulting in the highest accumulation of (semi-)metals in earthworms. This study clarifies the influence mechanisms of MPs with different sizes and levels on the accumulation of (semi-)metals by terrestrial invertebrates.
10.1016/j.envpol.2021.118194
Occurrence of microplastics and phthalate esters in urban runoff: A focus on the Persian Gulf coastline.
Hajiouni Shamim,Mohammadi Azam,Ramavandi Bahman,Arfaeinia Hossein,De-la-Torre Gabriel E,Tekle-Röttering Agnes,Dobaradaran Sina
The Science of the total environment
Urban runoff seems an obvious pathway for the transfer of microplastics (MPs) and phthalate acid esters (PAEs) from land-based sources to the marine environment; an issue that still lacks attention. This study presents the first results on MP and PAE levels in the urban runoff into the northern part of the Persian Gulf during the dry season. Average concentrations of MPs and PAEs in the urban runoff of eight selected sampling sites (N = 72) along the Bushehr coast were 1.86 items/L and 53.57 μg/L, respectively. MPs with a size range of 500-1000 μm had the highest abundance, and the mean levels of PAEs in MPs were 99.77 μg/g. The results of this study show that urban runoff is a main source of MP and PAE contaminants that are discharged into the Persian Gulf. Therefore, to decrease these pollutants from entering the aquatic environment, decision-makers in the area should consider this problem and stop the direct discharging of urban runoff into water bodies.
10.1016/j.scitotenv.2021.150559
Aging microplastics in wastewater pipeline networks and treatment processes: Physicochemical characteristics and Cd adsorption.
Li Xiaowei,Li Man,Mei Qingqing,Niu Shiyu,Wang Xuan,Xu Huafang,Dong Bin,Dai Xiaohu,Zhou John L
The Science of the total environment
Despite a wealth of information on removal of the microplastics (MPs) in wastewater treatment plants (WWTPs), little attention has been paid to how wastewater treatment process affect the MP physicochemical and adsorption characteristics. In this study, changes in physicochemical property of three MPs, i.e. polyamide (PA), polyethylene (PE) and polystyrene (PS) through the wastewater pipeline, grit and biological aeration tanks were investigated. The results show that compared with virgin MPs, the treated MPs have higher specific surface area and O content, and lower C and H contents, and glass transition temperature, implying that the three treatments cause the chain scission and oxidation of the MPs. Cd adsorption capacities of the MPs are higher than the corresponding virgin MPs after sulfidation in the pipeline (SWPN) and biological treatment in aeration tank (BTAT). Pearson correlation analysis shows that the increase is mainly resulted from the enhancement of the O-containing groups on the MPs. However, Cd adsorption capacities of the MPs decrease after mechanical abrasion in grit tank (MAGT), corresponding to the decrease in carbonyl index. Two dimensional FTIR correlation spectroscopy demonstrates that the NH bond in the PA plays a more important role than CH bond in the adsorption of Cd, but only change of the CH bond is found in the PE and PS. The findings provide new insights into the effect of WWTPs on the MP aging and physicochemical characteristics.
10.1016/j.scitotenv.2021.148940
Microplastics and trace metals in fish species of the Gulf of Mannar (Indian Ocean) and evaluation of human health.
Selvam S,Manisha A,Roy Priyadarsi D,Venkatramanan S,Chung S Y,Muthukumar P,Jesuraja K,Elgorban Abdallah M,Ahmed Bilal,Elzain Hussam Eldin
Environmental pollution (Barking, Essex : 1987)
The importance of microplastic (MPs) contamination in marine environments is reflected by increasing number of studies in fish species. Some even dedicated to the toxicological effects from the ingestion. Microplastics (MPs) and their trace metal composition were examined in the muscle and intestine of five commercially important fish species (i.e., Sufflamen fraenatus, Heniochus acuminatus, Atropus atropos, Pseudotriacanthus and Leiognathus brevirostris) from Thoothukudi at the Gulf of Mannar coast in south India. The abundance and morphology of MPs (size, shape, and texture) in muscle and intestinal were investigated by micro-Fourier Transform Infrared Spectroscopy (μ-FT-IR) and atomic force microscope (AFM). ICP-OES was used to investigate the adsorption/leaching of trace metals in microplastics in order to assess health risk for adults and children. Particles of 100-250 μm and white color dominated, and the mean abundances (items/100 g) of total MPs were more in Pseudotriacanthus (muscle: 51.2; intestine: 50.1) compared to Heniochus acuminatus (muscle: 9.6; intestine: 15), Leiognathus brevirostris (muscle: 12; intestine: 13.2) and Atropus atropus (muscle: 15.2; intestine: 44.1). Polyethylene (35.3%), polypropylene (27.2%), polyamide (nylon) (22.2%) and fiber (15.3%) represented the MPs present in muscles, and polyamide (nylon) (30.2%), polyethylene (28.1%), polypropylene (25.9%), and fiber (15.8%) composed the intestine MPs. We estimated possible consumption of 121-456 items of MPs/week by adults and about 19-68 items of MPs/week by children by considering the sizes of safe meals. Zn, Cu, Mn and Cr in these fish species reflected influence of the sewage waste. However, the non-carcinogenic risk evaluated through EDI, THQ, HI, and CR did not suggest any immediate health problem for the consumers.
10.1016/j.envpol.2021.118089
Polystyrene microplastics induce hepatotoxicity and disrupt lipid metabolism in the liver organoids.
The Science of the total environment
Microplastic particles (MP) has been detected in the environment widespread. Human beings are inevitably exposed to MP via multiple routines. However, the hazard identifications, as direct evidence of exposure and health risk, have not been fully characterized in human beings. Many studies suggest the liver is a potential target organ, but currently no study regarding the MP on human liver has been reported. In this study, we used a novel in vitro 3D model, the liver organoids (LOs) generated from human pluripotent stem cells, as an alternative model to the human liver, to explore the adverse biological effect of 1 μm polystyrene-MP (PS-MP) microbeads applying a non-static exposure approach. When the LOs were exposed to 0.25, 2.5 and 25 μg/mL PS-MP (the lowest one was relevant to the environmental concentrations, calculated to be 102 ± 7 items/mL). The potential mechanisms of PS-MP induced hepatotoxicity and lipotoxicity, in aspects of cytotoxicity, levels of key molecular markers, ATP production, alteration in lipid metabolism, ROS generation, oxidative stress and inflammation response, were determined. Specifically, it has been firstly observed that PS-MP could increase the expression of hepatic HNF4A and CYP2E1. Based on these findings, the potential adverse outcome pathways (AOPs) relevant to PS-MP were proposed, and the potential risks of PS-MP on liver steatosis, fibrosis and cancer were implicated. The combined application of novel LOs model and AOPs framework provides a new insight into the risk assessment of MP. Further studies are anticipated to validate the hepatotoxic molecular mechanism of PS-MP based on HNF4A or CYP2E1, and to investigate the MP-induced physical damage and its relationship to hepatic adverse effect for human beings. CAPSULE: Microplastics cause hepatotoxicity and disrupt lipid metabolism in the human pluripotent stem cells-derived liver organoids, providing evidence for human implication.
10.1016/j.scitotenv.2021.150328
Microplastics in agricultural soils, wastewater effluents and sewage sludge in Mauritius.
Ragoobur Doorgha,Huerta-Lwanga Esperanza,Somaroo Geeta Devi
The Science of the total environment
The rapid and silent emergence of microplastics (MPs) in the environment has recently become a global problem with more and more studies are showing the harmful effects of MPs on different ecosystems. The aim of this study was to investigate the presence of MPs in agricultural soils, wastewater effluents and sewage sludge in Mauritius. The soil samples were collected randomly from three different agricultural lands which have been used for conventional agriculture for more than 25 years. Wastewater effluents and sewage sludge were collected once, using the grab sampling method, from three main operating wastewater treatment plants (WWTP) across the island and were analysed in triplicate. MPs were extracted using the flotation technique, followed by hydrogen peroxide digestion. The abundance of MPs was found to be 320.0 ± 112.2 and 420.0 ± 244.0 particles.kg in shallow and deep soils, respectively, out of which 42.4% and 95.8% were less than 1 mm in size, respectively. Site 3 had the highest abundance of MPs due to cumulated plastic debris dumped on the field. In addition, the average MPs concentration in sewage sludge and in wastewater effluents were 14,750 ± 8612.9 particles.kg and 276.3 ± 137.3 particles.L, respectively, whereby 90% of the MPs were less than 0.5 mm in size. WWTP 1 had the largest share of MPs in both sewage sludge and wastewater effluents. The attenuated total reflection Fourier transform infrared spectroscopy revealed that polypropylene (fibres, fragments, and flakes) was in abundance in agricultural soil samples by 56.26%, while in WWTP polyamide (fibres) was predominant by 88.85%. The findings of this preliminary study confirmed the presence of MPs in Mauritian lands, wastewater effluents and sewage sludge and therefore provide salient data to advocate for subsequent research on MPs.
10.1016/j.scitotenv.2021.149326
Adsorption behaviour and interaction of organic micropollutants with nano and microplastics - A review.
Yu Yangmei,Mo Wing Yin,Luukkonen Tero
The Science of the total environment
Nano/microplastics (NPs/MPs) and organic micropollutants are contaminants exerting serious threats to aquatic ecosystems, which are further aggravated through their interactions. Organic micropollutants can adsorb on the surface of NPs/MPs, enter to the digestive systems of aquatic organisms with NPs/MPs, and desorb from the surface inside the organism. Consequently, the migration behaviour of organic micropollutants is significantly affected increasing their risk to accumulate in the food chain. Therefore, understanding the adsorption interactions between NPs/MPs and organic micropollutants is critical for evaluating the fate and impact of NPs/MPs in the environment. This review article provides an overview about the role of NPs/MPs as (temporary) sinks for organic micropollutants but also as primary sources of organic micropollutants through the leaching of plastic additives. Specifically, the following aspects are discussed: adsorption/desorption mechanisms (e.g., hydrophobic partitioning interaction, surface adsorption by van der Waals forces or hydrogen bonding, and pore filling), influencing environmental factors (e.g., pH, salinity, and dissolved organic matter), leaching of plastic additives from NPs/MPs, and potential ecotoxicological effects arising from the interactions of NPs/MPs and organic micropollutants.
10.1016/j.scitotenv.2021.149140
A microfluidic chip enables fast analysis of water microplastics by optical spectroscopy.
Scientific reports
Microplastics contaminating drinking water is a growing issue that has been the focus of a few recent studies, where a major bottleneck is the time-consuming analysis. In this work, a micro-optofluidic platform is proposed for fast quantification of microplastic particles, the identification of their chemical nature and size, especially in the 1-100 µm size range. Micro-reservoirs ahead of micro-filters are designed to accumulate all trapped solid particles in an ultra-compact area, which enables fast imaging and optical spectroscopy to determine the plastic nature and type. Furthermore, passive size sorting is implemented for splitting the particles according to their size range in different reservoirs. Besides, flow cytometry is used as a reference method for retrieving the size distribution of samples, where chemical nature information is lost. The proof of concept of the micro-optofluidic platform is validated using model samples where standard plastic particles of different size and chemical nature are mixed.
10.1038/s41598-021-89960-4
Missing relationship between meso- and microplastics in adjacent soils and sediments.
Xu Li,Han Lihua,Li Jing,Zhang Hao,Jones Kevin,Xu Elvis Genbo
Journal of hazardous materials
Meso- and microplastics (MMPs) have attracted attention as globally dispersed environmental pollutants. However, little is known about the transfers of MMPs between aquatic and terrestrial systems. A large watershed-estuarine area of Bohai Sea was used as a case study, and soils and sediments were sampled adjacent to each other at a wide range of sites. MMPs were detected in all sediments (6.7-320 MMPs/kg) and soils (40-980 MMPs/kg), with the average abundance in soils double that in sediments on a dry mass basis. MMPs < 1 mm were most abundant and the dominant shape was film in both sediments and soils. Over twenty polymer types were detected and their compositions in sediments and soils were different. MMP abundance in sediments was lower in the upper catchment than the lower catchment, while the abundance of soil MMPs was the opposite. Despite the proximity of the sampling locations, no clear relationship was identified between the soil and sediment MMPs, suggesting low transfer between the two compartments and high heterogeneity of the sources. The missing associations between aquatic and terrestrial MMPs should be systematically examined in future studies, which is crucial for understanding the environmental fate and impacts of MMPs.
10.1016/j.jhazmat.2021.127234
Microplastics in beluga whale (Delphinapterus leucas) prey: An exploratory assessment of trophic transfer in the Beaufort Sea.
Moore R C,Noel M,Etemadifar A,Loseto L,Posacka A M,Bendell L,Ross P S
The Science of the total environment
Microplastics (MPs, <5 mm in length) have been identified as emerging contaminants in marine environments, with ingestion by a variety of biota being of increasing concern. Few studies exist on MP ingestion in Arctic fish, and there are currently no such data from the Beaufort Sea. We investigated MP abundance in five ecologically valuable species from three sampling sites in the Eastern Beaufort Sea to evaluate possible trophic-level pathways of MPs from prey to beluga whales. Polymer analysis confirmed that 21% of fish gastrointestinal tracts (n = 116) contained microplastic particles. Fish that contained MPs had a mean abundance of 1.42 ± 0.44 particles per individual and an overall mean abundance of 0.37 ± 0.16 particles. No plastic particles >5 mm were found, and 78% of the particles observed were fibers. Based on energetic needs, we estimate that individual beluga may ingest between 3800 and 145,000 microplastics annually through trophic transfer, with uncertain health implications.
10.1016/j.scitotenv.2021.150201
Genomic and proteomic profiles of biofilms on microplastics are decoupled from artificial surface properties.
Oberbeckmann Sonja,Bartosik Daniel,Huang Sixing,Werner Johannes,Hirschfeld Claudia,Wibberg Daniel,Heiden Stefan E,Bunk Boyke,Overmann Jörg,Becher Dörte,Kalinowski Jörn,Schweder Thomas,Labrenz Matthias,Markert Stephanie
Environmental microbiology
Microplastics in marine ecosystems are colonized by diverse prokaryotic and eukaryotic communities. How these communities and their functional profiles are shaped by the artificial surfaces remains broadly unknown. In order to close this knowledge gap, we set up an in situ experiment with pellets of the polyolefin polymer polyethylene (PE), the aromatic hydrocarbon polymer polystyrene (PS), and wooden beads along a coastal to estuarine gradient in the Baltic Sea, Germany. We used an integrated metagenomics/metaproteomics approach to evaluate the genomic potential as well as protein expression levels of aquatic plastic biofilms. Our results suggest that material properties had a minor influence on the plastic-associated assemblages, as genomic and proteomic profiles of communities associated with the structurally different polymers PE and PS were highly similar, hence polymer-unspecific. Instead, it seemed that these communities were shaped by biogeographic factors. Wood, on the other hand, induced the formation of substrate-specific biofilms and served as nutrient source itself. Our study indicates that, while PE and PS microplastics may be relevant in the photic zone as opportunistic colonization grounds for phototrophic microorganisms, they appear not to be subject to biodegradation or serve as vectors for pathogenic microorganisms in marine habitats.
10.1111/1462-2920.15531
Microwave-Assisted Extraction for Quantification of Microplastics Using Pyrolysis-Gas Chromatography/Mass Spectrometry.
Environmental toxicology and chemistry
Microplastics are now recognized as a persistent and global pollutant. To quantitively measure microplastics in environmental matrices, several techniques are used including new methods using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In the present study, a new extraction method using microwave-assisted extraction (MAE) combined with Py-GC/MS was developed to extract and quantify a wide range of plastic polymers, and the method was validated using different environmental matrices. This new extraction method was able to extract polyethylene, polystyrene, polypropylene, poly(methyl-methacrylate) (PMMA), polyvinylchloride (PVC), and polycarbonate in dichloromethane with good recoveries (92.9-119.7%). The limit of detection and limit of quantification (LOQ) of the method ranged from 0.002 to 0.18 µg and from 1.2 to 5.8 µg, respectively. Intra- and interday repeatability values with coefficients of variation less than 25% for all polymers were obtained. Method validation also included a spike and recovery using all polymers from clean water, dirty water, and shrimp and salmon fillet samples, with recoveries of 85 to 111, 87 to 138, 81 to 122, and 50 to 151%, respectively. Finally, the method was tested on unspiked wild mussels and bottled water for proof-of-concept. Both polyethylene and PVC were detected and quantified in mussels, and polycarbonate and polypropylene were detected below the LOQ. For bottled water, polypropylene, polystyrene, and polycarbonate were all detected below the LOQ. We introduce a method combining MAE and Py-GC/MS as a tool for mass quantification of microplastics. This method can be used as a stand-alone, or as a complementary method to spectroscopic techniques. Environ Toxicol Chem 2021;40:2733-2741. © 2021 SETAC.
10.1002/etc.5179
Microplastics deteriorate the removal efficiency of antibiotic resistance genes during aerobic sludge digestion.
Zhang Zehao,Liu Huan,Wen Haiting,Gao Li,Gong Yanyan,Guo Wenshan,Wang Zhiyao,Li Xuan,Wang Qilin
The Science of the total environment
Sludge from wastewater treatment plants (WWTPs) is considered to be reservoirs of antibiotic resistance genes (ARGs), which can be efficiently removed by sludge treatment processes, e.g., aerobic sludge digestion. However, recent studies report microplastics, which also accumulate in sludge, may serve as carriers for ARGs. In the presence of microplastics, whether ARGs can still be efficiently destroyed by aerobic sludge digestion remains to be urgently investigated. In this study, the fate of ARGs during aerobic digestion was investigated with and without the addition of three prevalent categories of (i.e., polyvinyl chloride (PVC), polyethylene (PE), and polyethylene terephthalate (PET)). Nine ARGs and class 1 integron-integrase gene (intI1) that represents the horizontal transfer potential of ARGs were tested in this study. Compared with the control, the ARGs removal efficiency decreased by 129.6%, 137.0%, and 227.6% with the presence of PVC, PE, and PET, respectively, although a negligible difference was observed with their solids reduction efficiencies. The abundance of potential bacterial hosts of ARGs and intI1 increased in the reactors with the addition of microplastics, suggesting that microplastics potentially selectively enriched bacterial hosts and promoted the horizontal transfer of ARGs during aerobic sludge digestion. These may have contributed to the deteriorated ARGs removal efficiency. This study demonstrated that microplastics in sludge would decrease the ARGs removal efficiency in aerobic digestion process, potentially leading to more ARGs entering the local environment during sludge disposal or utilization.
10.1016/j.scitotenv.2021.149344
Dangerous microplastics in topshells and anemones along the north coast of Spain.
Janssens Lotte,Garcia-Vazquez Eva
Marine pollution bulletin
While levels of microplastics and other pollutants keep increasing in all coastal habitats, seafood is being eaten all over the world. In this research, three edible species were sampled from six points along the central north coast of Spain: Actinia equina anemones and Phorcus lineatus and Steromphala umbilicaris topshells (N = 100). Putative microplastics (N = 2157) were identified, counted, and many analyzed through FT-IR spectroscopy. Herbivorous topshells contained significantly more microplastics than carnivorous anemones. The most common particles were fibers, with transparent, blue and black as most prominent colours. Plastics included PE, polyester, PET, PP, nylon, PS, PVB and acrylic fibers. The sampled items contained several harmful compounds, including PTTC of which even one particle could be fatal if inhaled. This highlights the urgent need for studies regarding the safety of seafood.
10.1016/j.marpolbul.2021.112945
Microplastics pollution in the ocean: Potential carrier of resistant bacteria and resistance genes.
Stenger K S,Wikmark O G,Bezuidenhout C C,Molale-Tom L G
Environmental pollution (Barking, Essex : 1987)
Microplastics pollution in marine environments is concerning. Microplastics persist and accumulate in various sections of the ocean where they present opportunity for micropollutant accumulation and microbial colonisation. Even though biofilm formation on plastics was first reported in the 1970's, it is only in recent years were plastic associated biofilms have gained research attention. Plastic surfaces pose a problem as they are a niche ready for colonisation by diverse biofilm assemblages, composed of specific bacterial communities and putative pathogens prone to acquiring ARGs and resistance in the biofilm. However, the nature of antibiotic resistance on aquatic plastic debris is not yet fully understood and remains a concern. Given the inevitable increase of plastic production and waste generation, microplastics released into the environment may prove to be problematic. This review explores microplastic waste in the ocean and possible concerns that may arise from the presence of microplastics in conjunction with favourable conditions for the development and dispersal of antibiotic resistance in the ocean and food web.
10.1016/j.envpol.2021.118130
Field to laboratory comparison of metal accumulation on aged microplastics in coastal waters.
Xie Minwei,Huang Jun-Lin,Lin Zhi,Chen Rong,Tan Qiao-Guo
The Science of the total environment
The ubiquity of microplastics in the environment has attracted much attention on their risks. Though newly produced plastics were considered inert to aqueous metals, a few studies suggest aged microplastics can accumulate metals. Still, knowledge gap exists on the comparability of metal accumulation in field condition and that acquired in controlled laboratory settings. Accordingly, we comparatively assessed the field accumulation and laboratory adsorption of metals on aged microplastics in coastal waters. Microplastics of different polymeric types were aged for 8 weeks at three coastal sites with different contamination levels. Microplastics accumulated metals to substantial concentrations during ageing (median concentrations, μg g: Fe = 950, Mn = 94, Zn = 19, Cu = 2.8, Ni = 1.7, Pb = 1.6, and Cd = 0.005). Adsorption capacity of (aged) microplastics was evaluated in laboratory using a stable isotope tracer method. At environmentally realistic concentrations (μg L, Cd = 1.7, Cu = 4.4, Ni = 5.4, Pb = 0.5, and Zn = 13), the median concentrations of newly adsorbed isotopes on the aged microplastics were 0.01, 1.4, 0.07, 0.56, and 1.1 μg g, respectively, one to two orders of magnitude higher than those adsorbed on pristine microplastics. However, the composition pattern of metals accumulated on aged microplastics differed from the composition of metals newly adsorbed in laboratory: the prior one reflected the contamination status of ageing sites and varied by polymeric types; whereas the laboratory newly adsorbed metals on aged microplastics were uniformly correlated to particulate Fe and Mn concentrations, suggesting Fe and Mn mineral coatings mediated the ensuing metal adsorption. Such discrepancy unveiled the complexity of metal accumulation behavior in the real environment and highlighted that cares should be taken when translating laboratory findings to risk assessment of metal contaminated microplastics in the real environment.
10.1016/j.scitotenv.2021.149108
Horizontal variation of microplastics with tidal fluctuation in the Chao Phraya River Estuary, Thailand.
Oo Phyo Zaw,Boontanon Suwanna Kitpati,Boontanon Narin,Tanaka Shuhei,Fujii Shigeo
Marine pollution bulletin
Microplastic (MP) pollution in estuarine environments is poorly characterized globally, although they are extensive buffer regions between terrestrial, freshwater and seawater environments. This research aims to investigate MP pollution levels and variations of MPs abundance with tidal fluctuation. Fourteen samples were collected from the surface water of the Chao Phraya River Estuary, Thailand using the Manta net at flood and ebb tides. The average abundance of microplastics at flood tide was 5.16 × 10 particles/km and at ebb tide was 3.11 × 10 particles/km. The abundance of microplastics in the estuary was directly related to the tidal fluctuation, creating an accumulation of microplastics in the study area. Polypropylene, polyethylene, and polystyrene were the most common polymers. The findings provide important information on the pollution status of microplastics in the Chao Phraya River Estuary and the variation of suspended microplastics with tidal fluctuation should be considered in future estuarine microplastic studies.
10.1016/j.marpolbul.2021.112933
Effects of seasonal variation and resuspension on microplastics in river sediments.
Xia Feiyang,Yao Quanwei,Zhang Jun,Wang Dunqiu
Environmental pollution (Barking, Essex : 1987)
Although microplastics are an emerging pollutant of global concern, little is known about the environmental behavior of microplastic in sediments. This study investigated the occurrence and seasonal variation of microplastics in the sediments of Liangfeng River, China with a fluorescence staining method, and then explored the transfer of microplastics at the water and sediment interfaces during resuspension. The results showed that smaller microplastics were detected in the sediments, which were concentrated in the size range of 50-500 μm. Microplastic abundance in the sediments in the dry season were slightly higher than those from the rainy season, and the rainy season promotes the accumulation of smaller microplastics in the sediment along the river-flow direction but not for the dry season. The shape of microplastics were predominantly fibers, followed by fragments and films. Polyethylene was the most abundant polymer, accounting for more than 50% of the total. Microplastics in the surface sediment move both to the overlying water and deeper sediment during the disturbance process. Disturbance-induced resuspension and vertical transport have significant effects on small-sized microplastics (50-500 μm). Small-sized microplastics can potentially migrate and redistribute via resuspension at different temporal and spatial scales, as some extent of resuspension is occurring in most river systems, especially in urban areas with boat traffic.
10.1016/j.envpol.2021.117403
Improved Raman spectroscopy-based approach to assess microplastics in seafood.
Leung Matthew Ming-Lok,Ho Yuen-Wa,Lee Cheng-Hao,Wang Youji,Hu Menghong,Kwok Kevin Wing Hin,Chua Song-Lin,Fang James Kar-Hei
Environmental pollution (Barking, Essex : 1987)
Microplastics represent an emerging environmental issue and have been found almost everywhere including seafood, raising a great concern about the ecological and human health risks they pose. This study addressed the common technical challenges in the assessment of microplastics in seafood by developing an improved protocol based on Raman spectroscopy and using the green-lipped mussel Perna viridis and the Japanese jack mackerel Trachurus japonicus as the test models. Our findings identified a type of stainless-steel filter membranes with minimal Raman interference, and a combination of chemicals that achieved 99-100% digestion efficiency for both organic and inorganic biomass. This combined chemical treatment reached 90-100% recovery rates for seven types of microplastics, on which the surface modification was considered negligible and did not affect the accuracy of polymer identification based on Raman spectra, which showed 94-99% similarity to corresponding untreated microplastics. The developed extraction method for microplastics was further combined with an automated Raman mapping approach, from which our results confirmed the presence of microplastics in P. viridis and T. japonicus collected from Hong Kong waters. Identified microplastics included polypropylene, polyethylene, polystyrene and poly(ethylene terephthalate), mainly in the form of fragments and fibres. Our protocol is applicable to other biological samples, and provides an improved alternative to streamline the workflow of microplastic analysis for routine monitoring purposes.
10.1016/j.envpol.2021.117648
Microplastics influence on Hg methylation in diverse paddy soils.
Yang Xu,Li Zihao,Ma Chi,Yang Zhongzhu,Wei Jingjing,Wang Tantan,Wen Xin,Chen Wenhao,Shi Xiaohong,Zhang Yi,Zhang Chang
Journal of hazardous materials
Microplastics are widespread in estuarine, coastal, and deep sea sediments. The influence of microplastics on mercury (Hg) methylation in paddy soils with different characteristics, however, has not been well reported. In this research, we conducted a microcosmic experiment using red soil and alkaline soil with 2%, 7% and 10% polyvinyl chloride microplastics (PVC-MPs). Diffusive gradients in thin film (DGT) were used to test bioavailable Hg and bioavailable methylmercury (MeHg) in soils. Results showed that PVC-MPs could decrease bioavailable MeHg concentrations both in red soil and alkaline soil. We demonstrated that these decreases could be due to three possible mechanisms: (1) PVC-MPs affected DOM composition, which resulted in a difference in combining capacity for bioavailable Hg; (2) PVC-MPs decreased MeHg via changing soil properties (including sulfate and dissolved Fe); (3) PVC-MPs affected the abundance of Proteobacteria, Firmicutes, and hgcA gene in soils. Our results emphasized the significance of investigating effects of microplastics on specific contaminants to implement effective environmental remediation strategies in polluted paddy soils.
10.1016/j.jhazmat.2021.126895
Presence of airborne microplastics in human lung tissue.
Amato-Lourenço Luís Fernando,Carvalho-Oliveira Regiani,Júnior Gabriel Ribeiro,Dos Santos Galvão Luciana,Ando Rômulo Augusto,Mauad Thais
Journal of hazardous materials
Plastics are ubiquitously used by societies, but most of the plastic waste is deposited in landfills and in the natural environment. Their degradation into submillimetre fragments, called microplastics, is a growing concern due to potential adverse effects on the environment and human health. Microplastics are present in the air and may be inhaled by humans, but whether they have deleterious effects on the respiratory system remain unknown. In this study, we determined the presence of microplastics in human lung tissues obtained at autopsies. Polymeric particles (n = 33) and fibres (n = 4) were observed in 13 of 20 tissue samples. All polymeric particles were smaller than 5.5 µm in size, and fibres ranged from 8.12 to 16.8 µm. The most frequently determined polymers were polyethylene and polypropylene. Deleterious health outcomes may be related to the heterogeneous characteristics of these contaminants in the respiratory system following inhalation.
10.1016/j.jhazmat.2021.126124
Atmospheric transport and deposition of microplastics in a subtropical urban environment.
Huang Yumei,He Tao,Yan Muting,Yang Lian,Gong Han,Wang Wenjing,Qing Xian,Wang Jun
Journal of hazardous materials
As an issue of great concern, microplastics pollution has emerged as a key environmental challenge of our time. The atmosphere is a significant compartment in the global cycle of microplastics, however, studies on the transport and deposition of airborne microplastics is limited. In the present work, atmospheric wet and dry deposition of microplastics were analyzed over one year in an urban environment of megacity Guangzhou, China. The atmospheric deposition fluxes of microplastics ranged from 51 to 178 particles/m/d (mean: 114 ± 40 particles/m/d). Fibers, fragments, films and microbeads were observed in the deposition samples, with fibers being the most abundant microplastics, accounting for 77.6 ± 19.1% of the total. The chemical composition of microplastics were identified using micro Fourier transform infrared spectrometer. 78.7% of the fibrous microplastics were derived from petrochemicals and most were polyethylene terephthalate (polyester), suggesting that textiles (e.g., clothes and curtains) were likely the main source. The results of back-trajectory analysis indicated that city rivers may act as secondary sources of airborne microplastics. Though no significant correlation was found between atmospheric microplastic deposition and meteorological factors such as rainfall and wind events, these factors were suggested to be positive drivers for the transport and deposition of airborne microplastic.
10.1016/j.jhazmat.2021.126168
Occurrence of microplastics in commercial marine dried fish in Asian countries.
Piyawardhana Nathangi,Weerathunga Veran,Chen Hsu-Sen,Guo Laodong,Huang Po-Jung,Ranatunga R R M K P,Hung Chin-Chang
Journal of hazardous materials
The major risk of microplastics in marine environments is the bioaccumulation in marine organisms. Plastic ingestion by marine organisms has been investigated and recently more attention has been given to microplastics in seafood. However, it is seldom reported the occurrence of microplastics in marine commercial dried fish products available for human consumption. Here, we report the occurrence of microplastics in 14different marine dried fish products from seven Asian countries. Microplastics were observed in most dried fish, with fibers representing ~80% of the total-microplastics. The major plastic polymers, identified using Micro-Raman spectroscopy, included polyethylene (35%), polyethylene terephthalate (26%), polystyrene (18%), polyvinyl chloride (12%), and polypropylene (9%). The highest count, in either per individual (1.92 ± 0.12) or per gram of dried fish (0.56 ± 0.03), were found in Etrumeus micropus from Japan. Marine dried fish, which are typically eaten whole, may contribute to the ingestion of microplastics by humans, posing potential health risks especially in Asian countries. Further studies are needed to identify the occurrence of smaller sized microplastics and nanoplastics and their potential health impacts.
10.1016/j.jhazmat.2021.127093
Microplastics pollution on Colombian Central Caribbean beaches.
Rangel-Buitrago Nelson,Arroyo-Olarte Harry,Trilleras Jorge,Arana Victoria Andrea,Mantilla-Barbosa Egna,Gracia C Adriana,Mendoza Anubis Velez,Neal William J,Williams Allan T,Micallef Anton
Marine pollution bulletin
The growing literature on microplastics (MPs) in coastal and marine environs reflects the seriousness of this pollutant category. Diverse litter studies on Colombia's Central Caribbean Coast have not presented detailed study of MPs' typology, magnitude or distribution. This baseline study presents for first time the MPs problem on 23 beaches in 75 km coastal reach between Punta Roca and Galerazamba, on the central Colombian Caribbean Coast. The Microplastics Pollution Index (MPPI) and Coefficient of Microplastic Impact (CMPI) were developed and applied along with the Environmental Status Index (ESI) and their integration through sector analysis, and mapping using Agglomerative Hierarchical Clustering and Multidimensional Scaling, and Principal Components Analysis. Microplastics abundances (densities) ranged from 2457 to 557 MPs/kg, similar to other global beaches and bays. The MPs Index for the 23 beaches classified 8 beaches as "Moderate," 10 beaches as "High" and 5 as "Very High." Microplastic fibers were the dominant typology at 83% of the combined beaches total (ranging from Moderate to Very High for individual beaches).
10.1016/j.marpolbul.2021.112685
Nanoplastics are neither microplastics nor engineered nanoparticles.
Nature nanotechnology
Increasing concern and research on the subject of plastic pollution has engaged the community of scientists working on the environmental health and safety of nanomaterials. While many of the methods developed in nano environment, health and safety work have general applicability to the study of particulate plastics, the nanometric size range has important consequences for both the analytical challenges of studying nanoscale plastics and the environmental implications of these incidental nanomaterials. Related to their size, nanoplastics are distinguished from microplastics with respect to their transport properties, interactions with light and natural colloids, a high fraction of particle molecules on the surface, bioavailability and diffusion times for the release of plastic additives. Moreover, they are distinguished from engineered nanomaterials because of their high particle heterogeneity and their potential for rapid further fragmentation in the environment. These characteristics impact environmental fate, potential effects on biota and human health, sampling and analysis. Like microplastics, incidentally produced nanoplastics exhibit a diversity of compositions and morphologies and a heterogeneity that is typically absent from engineered nanomaterials. Therefore, nanoscale plastics must be considered as distinct from both microplastics and engineered nanomaterials.
10.1038/s41565-021-00886-4
Interactions between microplastics/nanoplastics and vascular plants.
Yin Lingshi,Wen Xiaofeng,Huang Danlian,Du Chunyan,Deng Rui,Zhou Zhenyu,Tao Jiaxi,Li Ruijin,Zhou Wei,Wang Zeyu,Chen Haojie
Environmental pollution (Barking, Essex : 1987)
Microplastics and nanoplastics are distributed in the environments universally. The interrelationship between vascular plants and micro/nanoplastics began to attract attention in recent years. Based on the relevant literatures collected from various databases, this review focuses on two topics: 1) the effect of vascular plants on the fate of micro/nanoplastics; 2) the effects of micro/nanoplastics on vascular plants. The review of the available studies reveals that vascular plants can act as sinks for microplastics and nanoplastics as their surfaces can adsorb these plastics; moreover, nanoplastics can be internalized by plants. Plastics on the surfaces and in the interiors of vascular plants can cause various phytotoxicity effects, including impacts on growth, photosynthesis, and oxidative stress. Furthermore, the results and mechanisms of phytotoxicity effects caused by microplastics or nanoplastics can be very different. However, knowledge gaps still exist in the relationships between micro/nanoplastics and vascular plants based on the analysis of available studies; thus, potential subjects for future studies were proposed, including the fates, analysis methods, influencing factors, mechanisms of phytotoxicity, and further influences of microplastics and nanoplastics in the vascular plant ecosystems. This study presents a review of micro/nanoplastics-vascular plant research and reaches a basis for future research.
10.1016/j.envpol.2021.117999
Recent advances on ecological effects of microplastics on soil environment.
Ya Haobo,Jiang Bo,Xing Yi,Zhang Tian,Lv Mingjie,Wang Xin
The Science of the total environment
The mass production and wide application of plastics and their derivatives have led to the release of a large number of discarded plastic products into the natural environment, where they continue to accumulate due to their low recycling rate and long durability. These large pieces of plastic will gradually break into microplastics (<5 mm), which are highly persistent organic pollutants and attract worldwide attention due to their small particle size and potential threats to the ecosystem. Compared with the aquatic system, terrestrial systems such as soils, as sinks for microplastics, are more susceptible to plastic pollution. In this article, we comprehensively summarized the occurrence and sources of microplastics in terrestrial soil, and reviewed the eco-toxicological effects of microplastics in soil ecosystems, in terms of physical and chemical properties of soil, soil nutrient cycling, soil flora and fauna. The influence of microplastics on soil microbial community, and particularly the microbial community on the surface of microplastics, were examined in detail. The compound effects of microplastics and other pollutants, e.g., heavy metals and antibiotics, were addressed. Future challenges of research on microplastics include development of new techniques and standardization for the extraction and qualitative and quantitative analysis of microplastics in soils, toxic effects of microplastics at microbial or even molecular levels, the contribution of microplastics to antibiotic resistance genes migration, and unraveling microorganisms for the degradation of microplastics. This work provides as a better understanding of the occurrence, distribution and potential ecological risks of microplastics in terrestrial soil ecosystems.
10.1016/j.scitotenv.2021.149338
Conceptions of university students on microplastics in Germany.
Raab Patricia,Bogner Franz X
PloS one
Microplastics are a global challenge and a frequently studied environmental issue. Hence, the knowledge body about microplastics within the scientific community is growing fast and challenges an elaborated knowledge transfer from science to the general public. Just as well-informed people are the basis for reducing microplastics' impact on the environment, knowledge of the audience's conceptions is the basis for an accurate and successful dissemination of scientific findings. However, insights into the publics' perceptions of microplastics are still rare. The present study aimed to capture students' conceptions about microplastics based on their individual experiences following qualitative inductive, exploratory research. Therefore, 267 students of a state university in Germany responded to a paper-and-pencil questionnaire containing open and closed questions on microplastic-related conceptual understanding, risk perception, information behavior, sources, and sinks. The inductive classifying of all responses by a qualitative content analysis revealed six basic concepts: 1) Microplastics are mainly understood as small plastic particles. 2) Microplastics are closely associated with its negative consequences. 3) The most labeled source in households is plastic packaging. 4) Compared to other water bodies, microplastics are rarely suspected in groundwater. 5) A high threat awareness exists in classifying microplastics as very dangerous and dangerous. 6) Media such as TV or the Internet are the most crucial information sources while the school has less importance in acquiring information. It is precisely this pattern that indicates the need for profound science communication to establish a joint and scientifically sound knowledge base in society. Knowledge about conceptions of potential "customers" allows tailor-made scientific knowledge transfers to shape public awareness, initiate changes in thoughts and prepare the field for collaborative behavior.
10.1371/journal.pone.0257734
Effects of PET microplastics on the physiology of Drosophila.
Chemosphere
Microplastics, as a new type of pollution, have attracted global attention and have become a research focus in recent years. Given the small size of microplastics, they can be ingested by many organisms. In addition, microplastics can enter the human body through the food chain. So, the potential dangers of microplastics can't be ignored. This study took Drosophila as a model organism to delve the physiological effects of polyethylene terephthalate microplastics (PET-MPs). Here, we reported that the higher concentration of PET-MPs was, the more obvious the effect became. The amount of oviposition decreased in female flies exposed, indicating that microplastics affected reproduction. PET-MPs caused the decrease of triglyceride and glucose content in male flies, as well as the decrease of starvation resistance, suggesting the effect of microplastics on energy metabolism. In addition, the 24-h spontaneous activity of flies exposed to PET-MPs increased significantly. The experimental results can help understand the potential impact of microplastics on physiology.
10.1016/j.chemosphere.2021.131289
Ecological interception effect of mangroves on microplastics.
Liu Xiaoya,Liu Huatai,Chen Li,Wang Xinhong
Journal of hazardous materials
As the last barrier preventing river pollutants from entering the ocean, mangroves have strong absorption and purification abilities, and strong tolerance. We collected mangrove surface water and sediment samples from the Xixi Estuary of Xiamen city. The results showed that the abundance of microplastics in seawater ranged from 620 to 13,100 n/m, the abundance of microplastics in sediment ranged from 143 to 488 n/kg, the distribution of microplastics was uneven, and the abundance of microplastics in the Xixi Estuary mangrove was significantly higher than that in the non-mangrove area. The sediment column sample results also showed that microplastics were detected in each layer of the sediments, indicating that microplastics were trapped in each layer of mangrove sediments. Therefore, we believe that mangrove forests have an ecological interception effect on microplastics. After entering mangroves, microplastics are affected by tidal reciprocating current scouring, river runoff, sunlight, wind erosion and other factors and gradually break into increasingly smaller particles through physical, chemical and biological effects. Microplastics accumulate in the sediments and experience sedimentation, suspension and reprecipitation processes together with the surface sediments. Mangroves should be widely planted in estuaries to reduce microplastic entry into the ocean.
10.1016/j.jhazmat.2021.127231
Microplastics in aquatic environment: Challenges and perspectives.
Vivekanand Aashlesha Chekkala,Mohapatra Sanjeeb,Tyagi Vinay Kumar
Chemosphere
The occurrence of microplastics in the aquatic environment has become a growing concern globally. Microplastics pose a hazard to the ecological system, and their presence, particularly in the water, has an adverse impact on human health and the ecosystem. Microplastics are released into the environment directly from everyday used plastic items, degradation of plastics, industries, and wastewater treatment plants. Once these contaminants enter the water, aquatic life feeds on them, and microplastics enter the food chain and cause severe health hazards. An assessment of microplastics' ecological risks is essential; however, it is challenging in the present scenario due to limited information available. To fill these knowledge gaps, this paper comprehensively reviews the sources and transport of microplastics in the water environment and their environmental and health effects, global policy frameworks, analytical techniques for microplastic detection, and control strategies to prevent microplastics release in the aquatic environment.
10.1016/j.chemosphere.2021.131151
Fish Ingest Microplastics Unintentionally.
Li Bowen,Liang Weiwenhui,Liu Quan-Xing,Fu Shijian,Ma Cuizhu,Chen Qiqing,Su Lei,Craig Nicholas J,Shi Huahong
Environmental science & technology
Microplastics (size of plastic debris <5 mm) occur in various environments worldwide these days and cause detrimental effects on biota. However, the behavioral responses of fish to microplastics in feeding processes are not well understood. In the present study, juveniles from four fish species and two common shapes of microplastics were used to explore fish feeding responses. We found swallowing-feeding fish ingested more pellets than filtering- and sucking-feeding fish. With high-definition and high-speed observational experiments, we found that all species did not actively capture microfibers; instead, they passively sucked in microfibers while breathing. Surprisingly, fish showed a rejective behavior, which was spontaneously coughing up microfibers mixed with mucus. Nevertheless, some of the microfibers were still found in the gastrointestinal tracts and gills of fish, while abundances of ingested microfibers were increased in the presence of food. Our findings reveal a common phenomenon that fish ingest microplastics inadvertently rather than intentionally. We also provide insights into the pathways via which microplastics enter fish and potential strategies to assess future ecological risk and food safety related to microplastics.
10.1021/acs.est.1c01753
Microplastics: An overview on separation, identification and characterization of microplastics.
Tirkey Anita,Upadhyay Lata Sheo Bachan
Marine pollution bulletin
At present plastic residues has become grave threat to the environment. Microplastics are plastic residues with a size <5 mm, due to their small size it is very difficult to remove them from water bodies, sediments and air with available techniques. Nanoplastics are different in size range as nanoplastics are smaller than 1 μm in size. This review is an attempt to gather an insight towards microplastic and its associated point of concerns. The review will highlight some of the methods appropriate for microplastics sampling and techniques for its identification in environmental samples. Some of the sampling methods include sieving, filtration, visual sorting, digestion, density separation. While, identification techniques in practice are SEM-EDS, FTIR, NIR, Raman, NMR spectroscopy, etc. Still there is a need and scope for development of more economical and portable techniques in this direction.
10.1016/j.marpolbul.2021.112604