Widespread emerging and legacy contaminants across Alpine snow and surface waters revealed by non-target analysis

High-mountain environments are increasingly recognized not as pristine systems, but as dynamic reservoirs of anthropogenic contaminants influenced by long-range atmospheric transport and regional emissions. Here, surface snow and river waters from the Monte Bianco area (Italian Alps) were investigated using an integrated non-target screening strategy combining liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and gas chromatography-mass spectrometry (GC-MS) with orthogonal extraction workflows. This approach revealed an unexpectedly complex chemical fingerprint comprising 283 tentatively identified compounds spanning industrial additives, plasticizers, pharmaceuticals, flame retardants, pesticides, and tire-derived compounds. Multivariate chemometric analysis indicated compositional differences between high- and low-altitude snow samples, as well as between upstream and downstream river-water samples, suggesting spatial variability in contaminant fingerprints across the Monte Bianco area. The probable detection of endocrine-disrupting phthalates, organophosphate flame retardants, pesticides (imidacloprid), and UV filters (oxybenzone) indicates the occurrence of diverse chemical classes in remote alpine systems. These findings position high-elevation environments as integrative archives of global contaminant mixtures and potentially relevant matrices for studying contaminant storage and release processes. The integration of complementary analytical platforms and advanced chemometric tools proved an effective framework for broad environmental characterization and contaminant prioritization in remote ecosystems.