From Alpine Snow to Mediterranean Rivers: Non-Target Analysis of CECs in Contrasting Aquatic Environments

Contaminants of emerging concern (CECs) are increasingly detected in aquatic environments, including remote areas. Non-target analysis based on high-resolution mass spectrometry is a powerful strategy for characterizing complex mixtures, identifying chemical fingerprints, and prioritizing compounds not routinely monitored. This presentation compares two contrasting case studies: surface snow and river waters from the Monte Bianco area in the Italian Alps, and surface waters from the Serpis River in Spain. In the Monte Bianco study, an integrated approach combining LC-HRMS, GC-MS, and complementary extraction workflows revealed 284 identified contaminants, including industrial additives, plasticizers, pharmaceuticals, flame retardants, pesticides, ultraviolet filters, and tire-derived compounds. Multivariate chemometric analysis highlighted altitude-dependent and hydrological gradients along the snow–water continuum. The results indicate that high-mountain environments can act as reservoirs of legacy and contemporary-use chemicals, with remobilization during snowmelt. In the Serpis River study, water samples from 17 sites were analyzed by solid-phase extraction followed by non-target UPLC-HRMS using an Orbitrap Exploris 120 mass spectrometer (Fig. 1). A total of 329 compounds were annotated at confidence Level 2, mainly pharmaceuticals, endogenous metabolites, industrial chemicals, pesticides, and personal care products. Multivariate analysis revealed spatial patterns associated with wastewater treatment plant discharges, urban inputs, and industrial activities. Together, these studies demonstrate the value of combining non-target HRMS with multivariate analysis to investigate complex aquatic systems.