Microplastics in freshly fallen snow from remote high-altitude ecosystems of the Kaçkar mountains (Southeastern black Sea, Türkiye)

Abstract

Atmospheric transport is a primary mechanism for dispersing microplastics (MPs) to remote high-altitude ecosystems. This study presents the first assessment of microplastic contamination in freshly fallen snow from five high-altitude sites (Handüzü, Çağrankaya, Elevit, Ovit, and Tulumpınar) in the Kaçkar Mountains, Northeastern Black Sea region of Türkiye. Snow samples were collected during the 2023 winter season. The collection took place within 24 h of initial snowfall, guided by real-time meteorological data. MPs were found in snow at all sites, with concentrations ranging from 12 to 104 items L−1. The highest abundance was at Çağrankaya (2550 m, 104 items L−1), and the lowest was at Handüzü (1850 m, 12 items L−1). All detected particles were fibers, predominantly black and blue. The consistent morphotype and colour distribution, together with the remoteness of the sites, suggest that long-range atmospheric transport (LRAT) may be an important pathway of microplastic delivery, rather than local fragmentation alone.These findings highlight that even pristine alpine environments are part of the global plastic cycle and are vulnerable to pollution from distant sources. The release of synthetic fibres during snowmelt may contribute to their transfer into freshwater systems and grazing lands, where they could potentially influence water quality and enter local food webs. These processes may have ecological implications for mountain ecosystems, including endemic species, water resources, and livestock reliant on these environments. This study provides baseline data from a previously understudied region, which may support future monitoring and research on atmospheric MP deposition in remote high-mountain environments.