Atmospheric Deposition of Microplastics in South Central\nAppalachia in the United States

Due to the increased\nprevalence of plastic pollution globally,\natmospheric deposition of microplastics (MPs) is a significant issue\nthat needs to be better understood to identify potential consequences\nfor human health. This study is the first to quantify and characterize\natmospheric MP deposition in the Eastern United States. Passive sampling\nwas conducted at two locations within the Eastern United States, specifically\nin remote South Central Appalachia, from March to September 2023.\nEach location had five sampling periods, with collections over a 21\nday period. Samples were processed to remove biological material,\nand the presence of MPs was confirmed using Raman spectroscopy to\nmatch particles based on polymer similarity. The relative average\natmospheric MP deposition in South Central Appalachia was determined\nto be 68 MPs m<sup>–2</sup> d<sup>–1</sup>. Most verified\nMPs were fibers, and the most abundant polymer type identified was\npoly(ethylene terephthalate) PETE. This study’s average MP\ndeposition rate is qualitatively comparable to rates reported in other\nstudies that employed a similar methodology in a similar landscape.\nScaling up our measured deposition rate to all of South Central Appalachia,\nan area of over 94,000 km<sup>2</sup> and home to five million people,\nsuggests a yearly MP deposition of approximately 321 metric tonnes.\nOur study highlights the prevalence of MP deposition in the Eastern\nUnited States, providing baseline data for future work to further\nassess routes of MP introduction.