White and wonderful? Microplastics prevail in snow from the Alps to the Arctic

TLDR

Microplastics are ubiquitous, with substantial amounts found even in the Arctic, yet the pathways delivering them northward remain poorly understood. The study aimed to determine whether atmospheric transport contributes to microplastic deposition in Arctic snow. Researchers collected snow from Fram Strait ice floes, Swiss Alps, and populated European sites, identifying microplastics via Fourier transform infrared imaging in 20 of 21 samples. Arctic snow contained lower microplastic concentrations (0–14.4 × 10³ N L⁻¹) than European snow (0.19–154 × 10³ N L⁻¹), with dominant polymers including varnish, rubber, polyethylene, and polyamide, most particles being sub‑11 µm, underscoring atmospheric transport as a significant deposition pathway.

Abstract

Microplastics (MPs) are ubiquitous, and considerable quantities prevail even in the Arctic; however, there are large knowledge gaps regarding pathways to the North. To assess whether atmospheric transport plays a role, we analyzed snow samples from ice floes in Fram Strait. For comparison, we investigated snow samples from remote (Swiss Alps) and populated (Bremen, Bavaria) European sites. MPs were identified by Fourier transform infrared imaging in 20 of 21 samples. The MP concentration of Arctic snow was significantly lower (0 to 14.4 × 103 N liter-1) than European snow (0.19 × 103 to 154 × 103 N liter-1) but still substantial. Polymer composition varied strongly, but varnish, rubber, polyethylene, and polyamide dominated overall. Most particles were in the smallest size range indicating large numbers of particles below the detection limit of 11 μm. Our data highlight that atmospheric transport and deposition can be notable pathways for MPs meriting more research.