Plastic debris represents one of the most prevalent and persistent pollution problems in the marine environment. In particular, microplastics that are mainly degraded from larger plastic debris have ...become a growing environmental concern. However, studies on the degradation of plastics in the aquatic environment that hydrobios reside in have been limited, while several studies regarding the degradation of plastics have been conducted under outdoor or accelerated weathering conditions. Thus, observation of the degradation of three types of virgin plastic pellets exposed to UV irradiation in three different environments (i.e., simulated seawater, ultrapure water, and a waterless (air) condition) was carried out. Data on the changes in physical and chemical properties were collected. The FTIR spectra showed that hydroxyl groups and carbonyl groups developed in three types of weathered plastic pellets under the air and ultrapure water environmental conditions after 3months of UV irradiation, while only carbonyl groups were found in plastic pellets in the simulated seawater environment. In contrast, the Raman spectra showed no significant changes in the weathered plastic pellets, but there were different intensities of characteristic peaks after exposure to UV irradiation. In addition, SEM images illustrated that granular oxidation, cracks and flakes were common patterns during degradation, and the plastic pellets in the three different environments experienced different levels of chemical weathering. We suggest that further studies on the degradation processes of plastic debris are needed to predict the fate of plastic debris in the environment.
•Degradation of plastics under UV irradiation in different environments was studied.•Changes in chemical/physical properties were examined by FTIR, Raman, and SEM.•Similarities and discrepancies in the degradation processes were investigated.•Exposure time, oxygen content and the water chemistry are the important factors affecting the degradation degree.
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The occurrence of microplastics in the beach sand of the Bohai Sea was investigated for the first time. The Bohai Sea is the largest Chinese inner sea and its coastal region is one of the most ...densely urbanized and industrialized zones of China. Samples from three costal sites (i.e., Bijianshan, Xingcheng and Dongdaihe) were collected, quantified and identified for microplastic analysis. Effects of sample depth and tourism activity were investigated. Surface samples (2 cm) contained higher microplastic concentrations than deep samples (20 cm). Samples from the bathing beach exhibited higher microplastic concentrations than the non-bathing beach, suggesting the direct contribution of microplastics from tourism activity. Of eight types of microplastics that were found, PEVA (polyethylene vinyl acetate), LDPE (light density polyethylene) and PS (polystyrene) were the largest in abundances. Moreover, the non-plastic items from samples were analyzed and results revealed that the majority abundance of the observed non-plastics were viscose cellulose fibers. Further studies are required to evaluate the environmental hazards of microplastics, especially as they may “act as a contaminant transporter” to the Bohai Sea ecosystem.
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•Microplastics in bathing beaches and non-bathing beaches of Bohai Sea were quantified and characterized.•The abundance of microplastics was in the range of 102.9–163.3 pieces/kg sand.•Eight chemical types of microplastics were identified.•Effects of sampling depth and tourism activity on microplastic concentration were studied.•Viscose fibers were found to be the dominant non-plastic fibers.
The abundance and chemical composition of microplastics in the beach sand of the Bohai Sea seashore were investigated.
Microplastic pollution has exhibited a global distribution, including seas, lakes, rivers, and terrestrial environment in recent years. However, little attention was paid on the atmospheric ...environment, though the fact that plastic debris can escape as wind-blown debris was previously reported. Thus, characteristics of microplastics in the atmospheric fallout from Dongguan city were preliminarily studied. Microplastics of three different polymers, i.e., PE, PP, and PS, were identified. Diverse shapes of microplastics including fiber, foam, fragment, and film were found, and fiber was the dominant shape of the microplastics. SEM images illustrated that adhering particles, grooves, pits, fractures, and flakes were the common patterns of degradation. The concentrations of non-fibrous microplastics and fibers ranged from 175 to 313 particles/m
2
/day in the atmospheric fallout. Thus, dust emission and deposition between atmosphere, land surface, and aquatic environment were associated with the transportation of microplastics.
•The quantity and composition of microplastics are investigated at 5 sediment sites in China for the first time.•The number of microplastics was at the range of 251–436 items/50g ...sediment.•Polyesters, polyethylene terephthalate, high density polyesters and polystyrene were identified using u-FTIR.
Microplastics in sediments from the Beibu Gulf and the coastline of China Sea were investigated to evaluate the occurrence and abundance of microplastics in China for the first time. Microplastics (<5mm) were taken from sediments by a flotation method. The number of microplastics was counted by a fluorescence microscope, an instrument that is rarely used in the detection of microplastics in sediments. This instrument led to results that were satisfactory. Compared with other sampled areas, microplastics were found in massive concentrations in China. Four types of microplastics, HDPE, PET, PE and PS, were identified. The results will provide useful background information for further investigations.
There is much research on the occurrence, pollution characteristics and impacts of microplastics in the marine environment but this omits factors which play important roles in the analysis of ...microplastics. This review summarizes the methods and techniques in the extraction from sediment, seawater and organisms, and assesses their advantages and limitations according to different experimental conditions, such as salt solution and reagents added to remove organic matter. Similarly, this overview includes the enumeration methods of microplastics by many kinds of microscopes (e.g. stereomicroscope, fluorescent microscope, scanning electron microscope). Advantages and challenges of using micro-FTIR, ART-FTIR, FPA-FTIR, Pry-GC/MS, and Raman spectroscopy in the identification methods are also discussed. This review suggests that monitoring microplastics needs standardized protocols for extraction, identification and quantification and that further research on the effects of microplastics to human health is needed.
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•We summarized the basic techniques and easily omitted factors in the extraction from sediment, seawater and organism.•The impact of microscopies on the analysis of enumeration can not be negligible.•Advantages and challenges of using micro-FTIR, art-FTIR, Pry-GC/MS, Raman spectroscopy and EDS are discussed.
Additive metals are continuously released into the environment during the photo-degradation of plastics into microplastics, but this phenomenon has not been reported by many studies. Herein, we ...investigated the surface morphology changes along with the release of additive metals (Cr, Mn, Fe, Co, Cu, Zn, and Pb) during the degradation of three types of plastics, i.e., polypropylene (PP), polyethylene terephthalate (PET) and polyvinyl chloride (PVC), under UV light irradiation. FTIR results showed that 168 days of UV-irradiation led to the primary degradation of each plastic sample. The metal release could be found after 70 days UV-irradiation. The rate of metal release for the three plastics showed the following order: PP > PET ≈ PVC. In addition, the distribution and concentrations of the metals in the plastic could influence the release characteristics of each metal. Low release rate of Fe symbolized by the total metal release in the range of 4.28 ~10.27% as evident from the results of the primary degradation experiment, indicated the release of Fe occurring in the late stage of the plastic degradation or even in the microplastics-formation stage. As for the release of Co from PP, it was far lower than that of the other elements (0.35%), showing the same release characteristics as that of Fe. On the contrary, the release ratio of Pb from PP was 78.89% and was mainly concentrated in the early stage of the plastic degradation. The results help understanding the release behavior of the additive metals during the degradation of typical plastics under ultraviolet light irradiation.
Current studies on microplastic pollution mainly focus on marine systems. However, few studies have investigated microplastics in an urban lake. This research intends to use an urban lake (Songshan ...Lake) as an example to explore the pollution characteristics of microplastics and use the principal component as well as the heat map analysis to discuss the relationships between different shapes of microplastics. According to this study, the average abundance of microplastics in the surface water and surface sediments of Songshan Lake were, respectively, 2.29 ± 0.98 items/m3 and 244 ± 121 items/kg; thin films were the major microplastics in both media; transparent this type of color has the most microplastic content. The particle size of microplastics was mainly 0.18–0.6 mm (43.3%) in surface water and 1–2 mm (48.3%) in surface sediments. The composition included five polymers: polyethylene (PE), polypropylene (PP), polypropylene–polyethylene copolymer (PP–PE copolymer), polystyrene (PS), and polyvinyl chloride (PVC), among which PE (47%) and PP (36%) were the main components. Principal component analysis (PCA) showed that there was a positive correlation among the four shapes of microplastics: films, fragments, foams, and fibers. The heat map analysis showed that the same category of shape distribution features may be similar for each sampling site.
Microplastics have been a prevalent and persistent contamination problem in the global aquatic environment. In particular, microplastics that can adsorb persistent organic pollutants (POPs) and ...therefore transfer these POPs to organisms in the aquatic environment have received much attention. In this study, an investigation of microplastics in the surface water of the Feilaixia Reservoir (Guangdong Province, China), which is an important part of people's daily lives in Guangdong Province was carried out, mainly focusing on the characteristics and spatial distribution of microplastics, as well as microplastics and their adsorded PAHs in the surface water of the Feilaixia Reservoir were investigated. The average abundance of microplastics in the surface water of the Feilaixia Reservoir was 0.56 ± 0.45 items/m3. Six kinds of polymers, including polyethylene (PE), polypropylene (PP), polystyrene (PS), expanded polystyrene (EPS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET), were identified, among which PP (52.31%) and PE (27.39%) were the major compositions. Four shapes of microplastics, i.e., foams, films, fragments and fibers were found, and films (37.78%) being the main shape. The most common typical size of the plastic particles ranged from 0.6 to 2 mm (41.36%). The total concentration of the sixteen PAHs carried on the EPS, PE and PP microplastics ranged from 282.4 to 427.3 ng/g; chrysene, benzo ghi perylene, and phenanthrene were abundant in the samples, at concentrations of 39.5–89.6 ng/g, 34.6–56.8 ng/g and 25.6–45.6 ng/g, respectively. Based on the ratios of the PAH isomers (Flut/Py < 1 and Phe/Ant >10), it was speculated that the source of the PAHs may be derived from the imperfect combustion of fossil fuels.
•Microplastic contamination in the surface water of the Feilaixia Reservoir was studied.•Microplastics were identified as PE, PP, PS, PVC and PET, and categorized as film, fragment, foam and fiber shapes.•PAHs carried on microplastics from the Feilaixia Reservoir were studied by GC/MS.•The source of PAHs carried on microplastics mainly derived from the imperfect combustion of fossil fuels.
Materials subject to cyclic stress can succumb to fatigue, causing failure at stress levels much lower than those in static loading cases. Herein we discussed the viscoelastic behaviors of ...polystyrene/multi-walled carbon nanotube (MWCNT) composites during short-term creep and recovery under tensile cyclic loading. Both unmodified and ozone oxidized MWCNTs were applied. It was found in general that the creep strain of thermoplastics dropped with decreasing temperature and stress, and with increasing content of carbon nanotubes. Moreover, with the increased cycle number, the creep strain reduced remarkably. This trend would be even more obvious at high levels of stress and temperature. Further mechanism analysis indicated the network-like structure formed by the molecule chains and nanotubes caused the reduction of the creep strain, the increasing of recovery ratio and the restriction on the mobility of amorphous molecule chains.
Copy number variants (CNVs) associated with developmental delay and intellectual disability (DD/ID) continue to be identified in patients. This article reports identification of a chromosome 1q22 ...microdeletion as the genetic cause in a Chinese family affected by ID.
The proband was a 19-year-old pregnant woman referred for genetic counseling and prenatal diagnosis at 18 weeks of gestation. She had severe ID with basically normal stature (height 154 cm 0 SD, weight 61 kg - 0.2 SD, and head circumference 54 cm - 1.12 SD). Her distinctive facial features included a prominent forehead; flat face; flat nasal bridge and a short upturned nose; thin lips; and small ears. The proband's father was reported to have low intelligence, whereas her mother was of normal intelligence but with scoliosis. Chromosome microarray analysis (CMA) reveals that the proband, her father and the fetus all carry a 1q22 microdeletion of 936.3 Kb (arrGRCh37 1q22 (155016052_155952375)×1), which was not observed in her mother and paternal grandparents and uncles, suggesting a de novo mutation in the proband's father. The microdeletion involves 24 OMIM genes including
(also known as
and encoding a histone lysine methyltransferase). Of note, haploinsufficiency of
has been shown to be associated with neurodevelopmental disorders. Based on the inheritance of the detected CNV in the pedigree and similar CNVs associated with ID in public databases (Decipher, DGV and ClinVar) and literature, the detected CNV is considered as pathogenic. The family chose to terminate the pregnancy.
The identified 1q22 microdeletion including
is pathogenic and associated with ID. This case broadens the spectrum of ID-related CNVs and may be useful as a reference for clinicians.
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