Secrets in the Snow: Nontargeted Analysis of CECs in Mountain Environments Using UHPLC-HRMS

This work is part of the IN2AQUAS project, financed within the EU Horizon program, which aims to secure water quality from remote regions to the tropical belt. This study specifically focuses on detecting contaminants of emerging concern (CECs) in mountain snow, applying a nontargeted approach using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). Given the growing concerns regarding environmental pollution and its widespread effects, monitoring CECs in high-altitude snow is crucial for understanding the extent of anthropogenic contamination in secluted environments. To achieve this, three continuous snow sampling campaigns were carried out in the Monte Bianco area (Valle d’Aosta, Italy), allowing an assessment of both the presence and temporal variation of CECs in snow. The collected snow samples underwent solid-phase extraction (SPE) to concentrate for enhanced detection. Three types of WatersTM Oasis® cartridges were used for SPE to capture a wide range of contaminants, enhancing the analysis of CECs, including polar and non-polar compounds. The applied cartridges were: 1.) Hydrophilic-Lipophilic Balance (HLB), 2.) Weak-Anion Exchange (WAX) 3.) Mixed Anion Exchange (MAX). The samples were analyzed using UHPLC coupled with HRMS (Orbitrap Exploris 120, Thermo Scientific), a crucial technique for high-accuracy detection of CECs in environmental studies. Data processing and identification were performed using Compound Discoverer 3.3 (Thermo Scientific), which enhances analysis through advanced spectral matching and suspect screening. The findings reveal the presence of a broad range of CECs, including pharmaceutical compounds, personal care products, pesticides, phthalates, parabens, industrial chemicals, and other compounds. These results emphasize the far-reaching influence of anthropogenic pollution, even in remote, high-altitude environments. The detection of CECs in mountain snow highlights the necessity of implementing comprehensive monitoring strategies to assess pollution impacts in remote ecosystems and better understand the mechanisms of their mitigation.