Microplastic contamination in snow of a high mountain: A case study from Uludağ National Park, Türkiye

This study investigated the environmental impact of winter sports on microplastic (MP) contamination in the snow of a high mountain national park in Türkiye, focusing on the Uludağ's ski resort. Snow samples (aged and fresh surface snow, and snow cores) were collected from four sites along a ski route and analysed by stereomicroscopy for particle morphology and by Py-GC-MS for polymer identification and quantification, providing the first mass-based concentrations of MPs in snow from this region. MP concentrations in the aged snow samples ranged from 120 to 370 μg/L, while fresh snow samples contained lower concentrations of between 46 and 140 μg/L. Vertically, the highest concentration (375 μg/L) was found in the deepest layer (80–100 cm), and the lowest (51 μg/L) in the top layer (0–20 cm). Fibers were the dominant particle type (57%), followed by fragments (27%) and foams (11%). In terms of polymer composition, polyethylene terephthalate (PET) was the dominant polymer, accompanied by polyvinyl chloride (PVC), nylon 6 (N6), and nylon 6,6 (N6,6). The vertical distribution analysis demonstrated that MPs accumulated heterogeneously in snow layers over time, influenced by snowfall, wind transport, and snowmelt dynamics. The findings provide key insights into MP distribution and environmental fate in snow-covered mountainous ecosystems, emphasizing the need to better understand the impacts of winter sports and the long-term environmental consequences of MPs in snow.