High levels of microplastic pollution in the sediments and benthic organisms of the South Yellow Sea, China.

Microplastics, emerging contaminants in the ocean, are thought to sink and accumulate in sediments, and thus may pose a potential ecological risk to benthic communities. In this study, abundances and characteristics of microplastics in sediments and benthic organisms from the South Yellow Sea were investigated. First, we optimized the sediment sampling for microplastic analysis and found that the top layer (0-5 cm) had the highest abundance, and microplastic abundances decreased significantly with increase in sediment depth. The abundance of microplastics was 560-4205 n/kg dry weight in the surface sediments (the topmost 3 cm) of 14 sites and 1.7-47.0 n/g wet weight in the tissues of benthic organisms. Moreover, microplastic abundances in sediments and benthic organisms were both positively correlated with water depth. Fibers, transparent microplastics, and small microplastics (<0.5 mm) were the most dominant types in sediments and organisms. FTIR analysis showed that polypropylene (PP, 31%), polyester (PE, 24%), nylon (19%), and polystyrene (PS, 15%) were the most abundant polymers in sediments. The results of SEM showed rough surfaces and obvious cracks on the microplastics isolated from sediments. In addition, characteristics of microplastics in Ophiura sarsii, Crangon affinis, and Acila mirabilis were compared. Our results demonstrate that a comprehensive investigation of microplastics in sediments and benthic communities will help to fully understand the ecological risk of microplastic pollution.

Wang J ，Wang M ，Ru S ，Liu X ... -  《-》

Microplastic pollution in North Yellow Sea, China: Observations on occurrence, distribution and identification.

Microplastics are emerging contaminants and have attracted widespread environmental concerns about their negative effects on the marine ecosystems. In this study, we investigated the abundances, distributions and characteristics of microplastics in surface seawater and sediments from the North Yellow Sea. The results showed that the abundance of microplastics was 545 ± 282 items/m3 in surface seawater and 37.1 ± 42.7 items/kg dry weight in sediments, representing a medium microplastic pollution level compared with other sea areas. Small microplastics (<1 mm) made up >70% of the total microplastic numbers. Films and fibers were the dominant shapes of microplastics in both the surface seawater and sediments. Transparent microplastics were generally more common than microplastics of other colors. Based on the identification by a Fourier transform infrared microscope, polyethylene (PE) was the dominant composition of microplastics in surface seawater, while polypropylene (PP) was the most common polymer type in sediments. These results will improve our understanding of the environmental risks posed by microplastics to marine ecosystems.

Zhu L ，Bai H ，Chen B ，Sun X ，Qu K ，Xia B ... -  《-》

Microplastic pollution in the surface sediments collected from Sishili Bay, North Yellow Sea, China.

As a new emergence pollutant, microplastic has aroused wide concern from both scholars and the public. In this study, microplastic pollution in surface sediments from 28 stations in Sishili Bay was investigated. The average abundance of microplastics was 499.76 ± 370.07 items/kg (d.w.). Fiber was the majority shape of microplastics (86.37%), followed by film, fragment and pellet. Microplastics <500 μm accounted for more than half of the total microplastics. Eight polymer types including rayon, PE, PP, PA, PET, PS, PMMA and PU were identified. The main component was rayon (58.41%), followed by PP and PET. The microplastic pollution in surface sediments of Sishili Bay is moderate compared with other studies. Microplastic pollution level in port, sewage outfall, estuary and aquaculture area of Sishili Bay was relatively high, which indicated that microplastic pollution was mainly sourced from river and sewage discharge and maritime activities.

Zhang B ，Wu D ，Yang X ，Teng J ，Liu Y ，Zhang C ，Zhao J ，Yin X ，You L ，Liu Y ，Wang Q ... -  《-》

Microplastic pollution in surface sediments of urban water areas in Changsha, China: Abundance, composition, surface textures.

Microplastics pollution in the global marine environment has received much recent research attention. However, microplastics contamination of the freshwater environment has not been fully studied, especially with respect to the surface sediments of urban water areas in China. This study investigated surface sediment samples from twelve selected sites in Changsha, China. The average microplastic concentrations in the surface sediments of the urban water areas ranged from 270.17 ± 48.23 items·kg-1 to 866.59 ± 37.96 items·kg-1, and the highest concentration of microplastics was found in Yuejin Lake sediments. Most of the collected microplastics were transparent, and most were classified as fragments. Most microplastics (58.31%) were smaller than 1 mm across all samples. Raman analysis indicated that polystyrene dominated the sediments samples. This study provided framework for future studies of microplastics pollution in the surface sediment of urban water areas in China.

Wen X ，Du C ，Xu P ，Zeng G ，Huang D ，Yin L ，Yin Q ，Hu L ，Wan J ，Zhang J ，Tan S ，Deng R ... -  《-》

Microplastic pollution in deep-sea sediments and organisms of the Western Pacific Ocean.

Microplastics are ubiquitous in marine environments. Sediments and marine organisms are recognized as the carriers and final destinations of microplastics. However, research on the concentration and abundance of microplastics in deep-sea sediments and organisms is limited. In this study, samples of sediments and organisms were collected from deep-sea locations of the western Pacific Ocean, with the depth ranging from 4601 m to 5732 m. Microplastics were extracted from the samples and analyzed by micro-Fourier-transform infrared spectroscopy. The average abundance of microplastics in the sediments was 240 items per kg dry weight of sediment. The microplastics were predominantly fibrous in shape (52.5%), blue in color (45.0%), and less than 1 mm in size (90.0%). The most commonly detected polymers were poly(propylene-ethylene) copolymer (40.0%) and polyethylene terephthalate (27.5%). The concentrations of polychlorinated biphenyls (PCBs), which are representatives of persistent organic pollutants, in the pore water of sediment samples were also investigated. A significant correlation between the distribution of microplastics and the PCB concentrations in sediments was found (P = 0.016). Microplastics were also detected in deep-sea organisms (i.e., Crinoidea, Pheronematidae, Ophiuroidea, and Gammaridea) in the sampling region, with an abundance of 0-3 items per individual biological sample. This assessment of microplastics in deep-sea sediments and benthic organisms of the western Pacific Ocean confirms that microplastic pollution exists in the deep-sea ecosystems of this region.

Zhang D ，Liu X ，Huang W ，Li J ，Wang C ，Zhang D ，Zhang C ... -  《-》