Microplastic and Fibre Contamination in a Remote Mountain Lake in Switzerland

Abstract

The contamination of aquatic environments by microplastics has been largely documented in the last years, especially in oceans, rivers, and lakes, but their occurrence in remote mountain lakes has been scarcely considered. This work aims to investigate the presence and abundance of microplastics and fibres in a remote, alpine, and uninhabited lake in Switzerland (Sassolo). In this study, the water column as well as the sediments were analysed. The isolation of microplastics and fibres from the samples of the sediment was achieved with a digestion process using H2O2 and a density separation technique with NaI. Classification of microparticles (from 5 mm to 125 μm) was first developed with an optical microscope. Infrared spectroscopy was then used to identify and characterize the chemical nature of the microplastics and fibres. On average, 2.6 microplastics and 4.4 fibres per litre were identified in the water column. On the other hand, the results of the sediment samples revealed significant fibre concentrations compared to plastic microparticles (514 fibres and 33 microplastics per kilogram). The most abundant types of microplastic identified in the samples were composed of polyethylene (PE) and polypropylene (PP). Microplastic and fibre sources were not determined, but it is likely that the number of human activities in this area as well as aerial deposition are contributing to contaminate this remote environment with microplastics and fibres.

Temporal Archive of Atmospheric Microplastic Deposition Presented in Ombrotrophic Peat

“…The uppermost samples (2010−2015) present a deposition rate of 7.2 (±1.6) MP/m 2 / day (2620 (±577) MP/m 2 /year), equivalent to 2800 (±616) MP/kg (dry weight). These values are comparable to MP found in Arctic (≤6695 MP/kg), 40 Tibetan Plateau (8−563 MP/m 2 ), 41 and remote Swiss mountain lake sediments (100− 1300 MP/m 2 ) 42 and lower than published urban lake sediment MP findings (Tables S1 and S2). This declines to a deposition rate of less than 600 MP/m 2 /year prior to 2005 (equivalent to ≤900 MP/kg), with lower MP found in samples dated pre-1990s (<140 MP/m 2 /year, <300 MP/kg).…”

A systematic review of freshwater microplastics in water and sediments: Recommendations for harmonisation to enhance future study comparisons

“…MP contamination in lakes was also found to be related to the anthropogenic activities and population density (Ballent et al, 2016;Wong et al, 2020b) as well as hydrology and weather events (Hu et al, 2020;Oni et al, 2020). However, MPs have also been reported in remote lakes with limited human activities which may be caused by atmospheric transport and riverine input (Velasco et al, 2020;Zhang et al, 2016). Concerns about possible deposition of MPs in estuaries, which are transition zone between rivers and marine environments, were also affected by aforementioned factors as well as tidal cycles and elevation in adjacent mudflat.…”

Microplastic pollution in urban Lake Phewa, Nepal: the first report on abundance and composition in surface water of lake in different seasons

“…The sites were divided into 8 sections as inlet and outlet areas of the lake, dense, moderate, and less populated areas, center lake, temple area, and mixing area where drainage from the city is discharged. At each location, 5 L of surface water (0–20 cm in depth) was collected (Negrete Velasco et al 2020 ; Su et al 2016 ) by using a steel bucket. Then, it was filtered through a 75-μm brass sieve on site and carefully transferred into the glass bottle (Mao et al 2020 ) using 18.2-MΩ water (Millipore, Milli-Q).…”

“…Microplastics enter the freshwater environment through domestic wastewater effluent (Browne et al 2011 ), runoff from agricultural lands, and overflow of drains during storm or rain event (Eriksen et al 2013 ; Galgani et al 2015 ), factory spillage (Gasperi et al 2014 ), busy traffic (Klein and Fischer 2019 ), and atmospheric fallout (Allen et al 2019 ; Negrete Velasco et al 2020 ). Once released into the aquatic ecosystem, microplastics form a dynamic recycling process for its transport in the environment (Xiang et al 2021 ), which depends on the type of plastic waste and the local environmental conditions (Schwarz et al 2019 ).…”