黄海桑沟湾潮滩塑料垃圾与微塑料组成和来源研究

海岸带潮滩中微塑料来源复杂，大块塑料在物理、化学、生物等作用下的破碎是潮滩微塑料的主要来源之一。本研究调查了黄海桑沟湾7个潮滩中不同尺寸塑料垃圾的组成、丰度以及微塑料的形状、颜色、成分等，并通过定性和定量的方式研究塑料垃圾破碎与微塑料的关系以识别微塑料来源。结果表明，聚苯乙烯泡沫在5 mm～2.5 cm、1～5 mm与<1 mm尺寸范围的样品中分别占85%、97%和82%；在>2.5 cm的塑料样品中，与养殖相关的塑料占76%；塑料垃圾和微塑料的总体丰度随着尺寸的减小而增加2～4个数量级。1～5 mm的微塑料丰度与5 mm～2.5 cm的塑料垃圾丰度具有显著相关性。通过对比不同尺寸塑料垃圾与微塑料的形态和成分特征，识别出潮滩中的微塑料主要是由聚苯乙烯泡沫、聚乙烯浮子、黄色海绵、纤维渔绳以及聚丙烯绳等破碎形成，表明养殖活动是桑沟湾潮滩塑料垃圾及微塑料的重要来源。未来需进一步探索微塑料来源的鉴别方法，寻找识别微塑料来源的新证据。

Compositions and sources of plastic debris and microplastics in different sizes from the Sanggou bay beaches,Yellow Sea,China

The sources of microplastics in coastal areas are complex. The fragmentation of large plastics through physical, chemical and biological processes is one of the main sources of microplastics in the beaches. This study investigated the compositions, abundances, shapes, colors and components of plastic debris and the microplastics of different sizes in 7 beaches in Sanggou bay of the Yellow Sea. We also studied the relationships between the fragmentation of plastic debris and microplastics by qualitative and quantitative analysis, which can be used to identify the sources of the microplastics. The results showed that polystyrene foam accounted for 85%, 97% and 82% of the samples in the size range of 5 mm ~ 2.5 cm, 1 ~ 5 mm and <1 mm respectively. In plastic debris >2.5 cm, the types of the plastic debris related to mariculture accounted for 76%. The total abundances of plastic debris and microplastics increased by 2 ~ 4 orders of magnitude with the decrease of sizes.The abundances of microplastics and plastic debris in 1 ~ 5 mm and 5 mm ~ 2.5 cm were significantly correlated. By comparing the morphology and components characteristics of different sizes of plastic debris and microplastics, the sources of microplastics were identified as fragmentations from polystyrene foam, polyethylene float, yellow sponge, fiber fishing ropes and polypropylene film ropes. The results indicate that mariculture is one of the important sources of plastic debris and microplastics in beaches of Sangou bay. In the future, it is necessary to further explore the identification methods of sources and find new evidences to identify the sources of microplastics.