大连海岸带夏、秋季大气沉降(微)塑料的赋存特征及其表面生物膜特性

微塑料作为一种新污染物，在水体、土壤和大气环境介质中均有分布.相比于海洋和陆地环境中微塑料研究的广度和深度，大气微塑料的研究还处于起步阶段.目前，有关大气环境中微塑料研究较少，对其污染特征和潜在风险的认识还不足.因此，调查了大连海岸带夏、秋季大气沉降样品中微塑料的赋存特征，探索了大气沉降塑料碎片表面生物膜的群落结构与功能特征.结果表明，大连海岸带夏、秋季大气沉降微塑料类型以纤维类为主，颜色以透明、蓝色和黑色为主，粒径以小于1 mm为主，成分主要为聚对苯二甲酸乙二醇酯、赛璐玢和乙烯-丙烯-二烯三元共聚物等(>90%).大连海岸带夏、秋季大气微塑料表面风化特征明显，且有微生物的定殖和生物膜的形成.变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)和放线菌门(Actinobacteria)是构成大连海岸带夏、秋季大气沉降塑料碎片表面生物膜的优势菌群.基因功能预测结果表明，大连海岸带夏、秋季大气沉降塑料碎片附生生物膜中存在与人类疾病密切相关的功能基因.本研究结果可为大气微塑料及其附生生物膜的环境与健康风险评估提供科学依据.

Occurrence of Atmospheric (Micro)plastics and the Characteristics of the Plastic Associated Biofilms in the Coastal Zone of Dalian in Summer and Autumn

Microplastics have been considered emerging pollutants that are widely distributed in the water, soil, and atmospheric environment. Compared with the research breadth and depth of microplastics in marine and terrestrial environments, the study of atmospheric microplastics is still in its infancy. At present, there are few studies on microplastics in the atmospheric environment, and the understanding of their pollution characteristics and potential risks remains insufficient. In this study, the occurrence characteristics of atmospheric (micro)plastics were investigated in the coastal zone of Dalian in summer and autumn. The bacterial community structures and functions of plastic-associated biofilms in the coastal zone of Dalian in summer and autumn were also studied. The results of this study showed that the dominant type of atmospheric microplastics in Dalian was fiber, and the main colors of atmospheric microplastics were transparent, blue, and black. The dominant particle size range of the atmospheric microplastics was less than 1 mm, and the polymer compositions were mainly polyethylene terephthalate, cellophane, and ethylene-propylene-diene terpolymer (>90%). Obvious weathering characteristics and biofilm formation could be observed on the surface of atmospheric microplastics. Proteobacteria, Cyanobacteria, and Actinobacteria were the dominant bacterial phyla that colonized on the surface of atmospheric plastic debris in the coastal zone of Dalian in summer and autumn. The results from the prediction of gene function showed that several functional genes that are closely related to human diseases exist in the epiphytic biofilms of atmospheric plastic debris. The results of this study can provide a scientific basis for the environmental and health risk assessment of atmospheric microplastics and their associated biofilms.