Characterization of small micro- and nanoparticles in Antarctic snow by electron microscopy and raman micro-spectroscopy

The impact of the anthropic activities in Antarctica is a concerning issue. According to the Scientific Committee on Antarctic Research, attention has to be paid to the next-generation contaminants deriving from both long-range atmospheric transport and local sources. In this study, the capabilities of transmission electron microscopy with energy-dispersive X-ray spectroscopy and Raman micro-spectroscopy were exploited to evaluate the size, morphology, and chemical composition of small micro- and nanoparticles, as well as their aggregates, in surface snow samples collected during the 2020–2021 austral summer in the coastal area of Victoria Land near the Mario Zucchelli research station. The presence of biological particles, mineral dust, sea salts, and small carbonaceous and plastic micro- and nanoparticles was assessed. Sulfate, carbonate, and nitrate minerals were detected in all the samples, whereas polyethylene, poly(ethylene-co-vinyl-acetate), and different kinds of carbonaceous materials were predominantly identified in the samples closest to the research base. The presence of small micro- and nanoparticles containing heavy metals and plastic polymers in samples collected in the areas surrounding the Italian research base highlights the impact of anthropogenic activities on the polar environment, suggesting the need for continuous monitoring to evaluate possible threats to the delicate Antarctic ecosystem