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

Abstract

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.