# Pilot Study of Microplastics in Snow from the Zhetysu Region (Kazakhstan)
## 3 Results and Discussion
Polyethylene and polypropylene are widely used in the production of packaging. Polystyrene is also used in packaging materials, which contributes to their accumulation in natural ecosystems. The spatial distribution analysis of microplastic showed that high pollution is observed not only near settlements and roads but also in remote areas, including high-mountain areas. Figure 4 shows microplastic contents in the snow cover of the Zhetysu region in four different perspectives for a more detailed visualization of the spatial distribution of plastic particles. Thus, at point No. 50 (Ainabulak village, 1284 m above sea level), despite the minimum height of snow cover (4 cm), the concentration reached 12 particles/m\({}^{2}\), with the dominance of 0.1 mm fractions, indicating a high degree of local or near-atmospheric pollution, probably associated with the domestic and agricultural impact. However, at point No. 28 (Chimbulak village, 1513 m), located in a remote mountainous area and characterized by the maximum snow cover height (80.5 cm), seven particles/m\({}^{2}\) of microplastics were detected, including 0.2-0.3 mm (PE, PS). Taking into account the relief, the remoteness from cities, as well as the unlikelihood of local pollution at such points, the results allow us to speak about the confirmed role of transregional atmospheric transport of microplastics, including at altitudes above 1500 m. Similar results were recorded at points No. 27 (Baizeren village, 1157 m) and No. 44 (Araltobe village, 1564 m), where concentrations were found to be 5 and 10 particles/m\({}^{2}\) (PE, PS), respectively. Considering the morphometric characteristics of microplastics, the predominance of particles smaller than 0.5 mm can be noted. Particles 0.1 mm in size were recorded in more than 80% of all samples, including isolated sites, such as point No. 19 (Saryesik-Atyrau Sands, 5 particles, all 0.1 mm), which confirms the dominance of fine particles (PE, PS), which have high aerodynamic mobility and the ability for long-term suspension in the atmosphere. Such suspended particles are able to be transported by air streams for hundreds of kilometers and fall out together with snow in remote areas, which fully corresponds to modern ideas about the global circulation of microplastics in the atmosphere [58]. Large particles up to 6 mm in size were detected at some points, such as No. 29 (Koktuma station), which indicates a local origin but does not exclude the possibility of secondary redistribution from the underlying surface due to wind erosion or local pollution. Thus, the simultaneous presence of coarse and fine fractions in one sample is interpreted as the result of overlapping local and atmospheric transport and the interaction of MP deposition and re-deflation. The snow cover height varied widely, from 4 to 80.5 cm. But no direct correlation between snow thickness and microplastic concentration was established. Thus, at minimum snow cover heights (4-6 cm), points No. 50 and No. 51 recorded 12 and 4 particles/m\({}^{2}\), respectively, whereas at maximum values (e.g., point No. 30, 60 cm of snow), the MP concentration was 3 particles/m\({}^{2}\), with PE and PS predominance. These values confirm that the deposition of microplastics with precipitation can be intensive even with low snowfall. Their amount in the snow cover depends more on the intensity of precipitation and wind direction than on the total amount of snowfall. The influence of the proximity of large cities is also manifested in the form of a moderate correlation between the urbanization of the area and the microplastic concentration. Higher values were recorded in areas close to the cities of Zharkent (point No. 50-12 particles/m\({}^{2}\), No. 49-7 particles/m\({}^{2}\)), Tekeli (point No. 44-10 particles/m\({}^{2}\)), Taldykorgan (points No. 34 and No. 37-7 and 4 particles/m\({}^{2}\) each), and Usharal (point No. 5-8 particles/m\({}^{2}\)). However, in remote and sparsely populated areas (e.g., point No. 31-2 particles/m\({}^{2}\), point No.