Deposition of microplastics by snow in the Arctic

• Main Author: Hawly, Moritz
• Format: Thesis
• Language: unknown
• Published: 2021
• Subjects: Arctic; Sea ice
• Online Access: https://epic.awi.de/id/eprint/55062/; https://hdl.handle.net/10013/epic.686891a8-825b-41a0-b81b-686d3400cc53

As plastics are omnipresent in everyday products and indispensable in various industrial branches, contamination through bulk plastics is currently a serious environmental problem and particularly microplastics (MP) have become a leading contributor to the pollution of ecosystems. MP accumulate in different aquatic environments such as lakes, rivers and oceans, are taken up by organisms and are likely to pose ecological and health risks. The analysis of MP in environmental samples is therefore a key part to assess these hazards and understand their regional and global pathways. Since it is suggested that the majority of MP are smaller than 10 μm in diameter, the use of Raman microspectroscopy (RM) is an essential technique for MP detection and analysis. In recent years, studies on Arctic sea ice, surface ocean water and snow revealed MP contamination of the Arctic region. Within this work, 15 Arctic snow samples gathered during the MOSAiC expedition are characterized via RM. Regarding the inherently time-consuming analytical process, method development was necessary to extract parameters that produce sufficient spectral quality in a timeefficient manner and a subsampling mask was established. The analyzed area equals 13.0% of the initially prepared sample area and the final MP concentration was determined by extrapolation. The majority of particles were minerals in all samples. In 11 out of 15 samples the presence of MP was confirmed, and eight different types of plastic were identified. The most predominant singular plastic types were found to be polyethylene (18.2%), polystyrene (12.5%) and polyvinyl alcohol (13.6%). Resins as a cumulative class include 34.1% of all MP found. Statistical analysis did show slight similarities between samples that exceeded the limit of detection. The mean and highest concentration amount to 12.3 (± 7.1)×103 N L-1 and 29.2 (± 1.8)×103 N L-1, respectively, with the mean concentration exceeding former studies by one order in magnitude. This puts special emphasis on the successful analysis of particles smaller than 11 μm and stresses the need for RM when investigating environmental samples.