Microfibres, which are threadlike particles < 5 mm, are the most common type of microplastic reported in the environment. However, few studies have focused on their abundance in background natural environments. This study assessed the abundance of microfibres in rainfall samples (from four precipitation monitoring stations) and across three headwater lake catchments that were in remote, undeveloped areas, away from anthropogenic disturbance and anthropogenic emission sources (i.e., sites were background natural environments). Anthropogenic microfibres were observed in all samples using visual identification methods, with Raman spectroscopy confirming the presence of polyester film and synthetic pigments, e.g., indigo and hostasol green. The estimated annual average atmospheric deposition of microfibres was ~28,800 mf m-2. Meteorological variables, e.g., rain, wind direction, and relative humidity were correlated with the abundance of microfibres. The average abundance of microfibres in headwater lake catchments was 24 mf g-1 in moss, 0.70 mf m-3 in surface trawl, 9,690 mf m-3 in subsurface, 910 mf kg-1 in lake sediment and 576 mf kg-1 in lakeshore sediment.
Author Keywords: Atmospheric Deposition, Background Environments, Headwater Lake Catchments, Microfibres, Microplastics, Rainfall