| Marine environmental pollution is becoming more and more serious.A large number of small plastic fragments appear in the marine environment,and the particle size less than 5 mm is called microplastics.The bay is the sink of marine and coastal environmental pollutants.It is of great scientific significance to study the characteristics of microplastic pollution in the bay.In this paper,the Sanggou Bay in the Yellow Sea,China was selected as a typical research area.A series of systematic survey from point and line to plane scale was carried out in Sanggou Bay in September and December 2017,as well as June 2018,respectively.The abundance,types,particle size and spatial and temporal distribution of microplastics in the water bodies,tidal flat sediments,surrounding rivers and farmland soils of Sanggou Bay were analyzed.The main results are as follows:(1)The abundance range of microplastics in the water and sediment of Sanggou Bay is 1.8 ~ 41.8 and 23.7 ~ 170 ng / g,respectively.The high value of microplastic abundance mainly occurs in the coastal waters.And the abundance value shows the trend of decreasing from the bay to the outer sea.There are seasonal variations in the types and abundance of microplastics in Sanggou Bay,and the maximum abundance of microplastics is found in December.The high values of microplastic abundance in different water layers of Sanggou Bay occur in the middle layer(depth 5 m).The spatial distribution of microplastics in the bottom sediments of Sanggou Bay shows a tendency of decreasing out of the mouth of the microplastics abundance values of the inshore and central sites of the Bay.(2)The abundance of microplastics in the tidal flat sediment of Sanggou Bay ranges from 14 to 1246.8 N/kg.The highest value of microplastic abundance in the tidal flat of Sanggou Bay appears in the uncleared wild beach.The abundance of microplastics are related to natural factors such as tidal flat topography,vegetation and wind waves,as well as man-made factors such as regular cleaning,beach use and so on.The distribution of microplastics in the sediments of Sanggou Bay was obviously different in horizontal and vertical direction.A higher abundance of microplastics was found at the high tidal line of tidal flat and the depth of sediment profile 5 ~ 55 cm.(3)The microplastics abundance of the Gu River water bodies and sediments around Sanggou Bay is 2 ~ 13 N/L and 34.6 ~ 73.6 N/kg and the main type of microplastics is fiber and fragement respectively.The microplastics abundance in the farmland soils of Chudao is 17.1 × 150 N/kg.The main type of microplastics found in the framland soil is fiber,as well as other plastic wastes from aquaculture activities such as foams and fishing lines,indicating that microplastics pollution in the farmland soils is affected to some extent by local aquaculture activities.(4)The indoor simulation test found that the surface micro morphology and functional groups characteristics of polystyrene foam pellets were significantly changed after two months of UV irradiation in simulated air and beach environment,suggesting an obvious weathering of microplastics in the bay environment,which leads to potential environmental and ecological risks such as adsorption and enrichment of pollutants in the marine environment.Results from this study can provide a scientific basis for the study of pollution characteristics and risk management of microplastics in the Bay environment. |
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