海洋和海岸环境中的微塑料（<5 mm）作为一种新型的污染物近年来已逐渐受到国内外的关注。由于其颗粒小、数量多、分布广且易于被海洋鱼、贝类等生物体摄食，会构成生态风险。国际上，近年来有关微塑料污染研究的报道快速增加，而我国尚处于起步阶段。本研究选择我国北方海岸带潮滩为研究区，通过优化微塑料浮选、分离及鉴别方法，率先研究了北黄海及渤海典型潮滩地区微塑料的类型、粒径、丰度、分布及其影响因素，分析了微塑料形貌特征及表面附着物质，初步探明了渤海海面和部分海洋生物体中微塑料的积累状况，在方法学和基础数据方面为我国海岸及近海环境中微塑料污染及其生态风险研究提供了科学依据。
本研究针对滨海潮滩土壤或沉积物样本，建立了一套连续流动分离浮选装置，实现微塑料浮选分离的便捷性和高效性，回收率达到97%。运用该装置，成功获取河北曹妃甸典型潮滩土壤中不同类型和丰度的微塑料，并首次观测到塑料编织袋扁丝碎片类的微塑料，进一步验证了该分离方法的适用性。采用该装置及浮选分离方法，发现山东沿海旅游海滩（或荒滩）、河口、养殖区和渔船码头区潮滩土壤或沉积物中均存在颗粒类（聚乙烯）、发泡类（聚苯乙烯）、纤维类（低密度聚乙烯）、碎片类（聚乙烯或聚丙烯）和薄膜类（聚丙烯）微塑料，其中，以发泡类为主，占58%~92%，其次是碎片类，而颗粒类和薄膜类较少。个别点位以碎片类为主，主要为风化的工程塑料编织袋碎片。在微塑料大小上，小于1 mm的微塑料占主导地位（约占总数量60%）；在丰度上，具有空间差异性，与潮滩类型有关。从微塑料平均丰度来看，旅游海滩（或荒滩）中微塑料丰度为720.38±2059.09个/kg（以沉积物湿重计），河口区为149.95±219.95个/kg，渔船码头区为193.75±52.68个/kg，养殖区高于其他潮滩类型，达到2049.38±3980.66个/kg。不同质地潮滩中微塑料颗粒类型、大小和丰度也存在差异，沙质滩以>1 mm的发泡类微塑料为主，泥质滩则以<1 mm的碎片类微塑料为主。
在渤海表层海水微塑料调查中，选择渤海海峡客运航道近岸区和渤海中心远离海岸区两个样点进行了微塑料分析。发现了碎片类、纤维类和薄膜类等微塑料类型，渤海海峡客运航道海面微塑料丰度达27.0个/m³，渤海中心区为11.8个/m³。渤海微塑料污染及其来源和影响因素值得进一步研究。
通过调查分析渤海莱州湾、北黄海烟台渔人码头、广西北部湾等近海底栖生物体内微塑料积累状况，发现魁蚶（Scapharca broughtonii）、毛蚶（Scapharca kagoshimensis）、中国蛤蜊（Mactra chinensis）、菲律宾蛤仔（Ruditapes philippinarum）、皱纹绿螂（Glauconome corrugate）、日本蟳（Charybdis(Charybdis) japonica）、三疣梭子蟹（Portunus (Portunus) trituberculatus）、脉红螺（Rapana Venosa）等底栖生物体内均有微塑料积累，丰度在70~2000个/kg（以鲜重软组织计）之间，包括颗粒类、碎片类、纤维类和薄膜类。滨海潮滩和海水环境中的微塑料污染可能是这些底栖生物体内微塑料的主要来源，对近海生态系统构成风险。同时，这些底栖生物均是日常食用的海产品，因而可能通过食物链对人体健康带来潜在风险。
通过利用扫描电子显微镜和能谱仪对黄渤海典型潮滩土壤中分离的微塑料进行表面形貌及附着物质的鉴定表明：环境中的微塑料样品表面呈现明显的粗糙，裂纹等不均质现象；同时，表面裂缝中夹杂着土壤颗粒等杂质，或者附着铁氧化物等物质；一些微塑料表面还观察到疑似藻类的生物有机体和疑似石油的黑色油状物质等附着物。因此，长期存在于海岸带环境中的微塑料表面及其复杂，会成为环境污染物和生物体的载体，并通过在海洋环境中共迁移形成扩散污染。未来应更加关注海洋及海岸环境中微塑料的动态过程和生态效应。

Microplastics (<5 mm) are a type of emerging pollutants of concern worldwide in the coastal and ocean environment in recent years. Microplastics may pose risk to marine ecosystem because of their small size, high abundance, ubiquitous distribution and easily ingestion by marine organisms such as fish, shellfish, etc. The international reports on microplastics pollution have rapidly increased recently, but very few relevant papers can be found in China. Therefore, the objectives of this study are to (1) investigate the types, size, abundance, distribution and the factors affecting the occurrence of microplastics in the typical coastal zones from the north Yellow Sea to the Bohai Sea by optimizing the flotation, separation and identification methods; (2) to identify the morphology characteristics and substance adhered onto the surface of microplastics; (3) to investigate the accumulation of microplastics in Bohai Sea surface and some marine organisms. The results were expected to be a scientific basis for further investigations on the microplastics pollution and ecological risks in the coastal and marine environment by providing the methodology and basic dataset.
A set of continuous-flow and air floating separation apparatus has been developed for the separation of microplastics from soil and sediment samples efficiently. The recovery of microplastics from a sandy soil reached up to 97%. Various microplastics in shape types and abundance were obtained from a typical coastal soil sample (Caofeidian, Hebei Province) and a new type of fragments from woven plastic bags was observed using this apparatus, which indicated the applicability of this apparatus and method for microplastic separation in environmental samples.
A survey of microplastics was carried out in the tourism beaches (or virgin beaches), estuaries, aquaculture areas and fishing harbors along the coastal beaches of Shandong peninsula. The results indicated that pellets (polyethylene), styrofoam (polystyrene), fibers (low density polyethylene), fragments (polyethylene or polypropylene) and films (polypropylene) existed in the soils and sediments of these areas using the above-mentioned apparatus and methods. The styrofoam accounted for 58%~92% of the total abundance of the microplastics and was the dominant microplastic type in the study areas, followed by fragments. The abundance of fibers and films were relatively lower among the five microplastic shape types. However, the fragments from weathered woven plastic bags dominated in some specific sites. As for size of the microplastics, approximately 60% of them have a size of less than 1 mm. A spatial variability of the mciroplastic abundance could be found, which was in relation to the types of coastal beaches. The average abundances of microplastics from tourism beaches (or virgin beaches), estuaries and fishery harbors were 720.38 ± 2059.09, 149.95±219.95 and 193.75±52.68 n/kg (based on wet weight of the sample) respectively, which were all lower than that in the aquaculture area (2049.38±3980.66 n/kg). Moreover, both of the type and size of the microplastics were different among the beaches with various soil/sediment textures. The Styrofoam with diameter >1mm dominated in the sandy beaches, while the fragments with diameter <1mm dominated in the muddy beaches. A survey for the microplastics in the marine surface water was carried out in offshore end of the shipping lane of the Bohai Strait and the central area of the Bohai Sea. Fragments, fibers and films were found in these two locations. The abundance of suspended microplastics was 27.0 n/m³ and 11.8 n/m³ in the offshore of the Bohai Strait and in the central Bohai Sea, respectively. Further investigation is recommended for the microplastics distribution, sources and influencing factors in the Bohai Sea.
Microplastics accumulation in benthic organisms was also investigated using the samples from the Laizhou Bay (the Bohai Sea), Yantai Fisherman's Wharf (North of the Yellow Sea) in Shandong province and the Beibu Gulf in Guangxi province.  The results showed that the abundance of microplastics including granules, fragments, fibers and films in the Scapharca broughtonii, Scapharca kagoshimensis, Mactra chinensis, Ruditapes philippinarum, Glauconome corrugate, Charybdis(Charybdis) japonica, Portunus (Portunus) trituberculatus and Rapana Venosa ranged from 70 to 2000 n/kg (based on fresh weight of the soft tissue). The microplastics accumulation in these benthic organisms likely sourced from the coastal and marine environments, which pose risks to local coastal ecosystem. Moreover, the accumulation of the microplastics in the benthic organisms might cause a potential risk to human health by consumption of these organisms as seafood.
The morphology and substance adhered onto the surface of microplastics were identified using scanning electronic microscope combined with energy dispersive X-ray detector for the samples from the Yellow Sea and Bohai Sea. The results showed that the weathered surface of coastal microplastics was characterized of roughness and cracks. Soil particles and other impurities embedding in the cracks could be observed. The surface of the microplastics fouling with iron oxide, algae and crude oil could also be observed. Obviously the surface properties of microplastics are rather complicated due to the environmental weathering and fouling. Such a surface can act as a carrier for organisms and contaminants and the latter may be migrated in the marine environment together with the microplastics. Therefore, further researches are needed on dynamics process and ecological effects of the microplastics in coastal and marine environment in the future.