Levels and ecological risk of selected organic pollutants in the high-altitude alpine cryosphere - The Adamello-Brenta Natural Park (Italy) as a case study

It is known that pesticides and other organic pollutants are transported from lowlands and alpine valleys to high alpine summits, where they are stored in glaciers until melting occurs between July and September. In this study, we aimed to map glacial contamination by measuring the concentrations of currently used pesticides, synthetic fragrances, and polycyclic aromatic hydrocarbons (PAHs) in glacial and non-glacial meltwater from six sites in the Italian Alps located within the protected Adamello-Brenta Natural Park. We subsequently characterised the ecological risk of these contaminants to aquatic fauna. Chlorpyrifos, chlorpyrifos-methyl, terbuthylazine, galaxolide, tonalide, and PAHs were detected in July and September 2019 and 2020 across all sites. Risk characterisation indicated that PAHs posed a low risk to the alpine ecosystem at most of the sites, and medium risk was associated only with fluoranthene and pyrene at Mandrone in 2020. Regarding fragrances, herbicides, and chlorpyrifos-methyl, the calculated risk to aquatic biocenosis was acceptable under current European guidelines. Only chlorpyrifos posed an unacceptable risk to aquatic invertebrates at two sites: Amola (in July 2019) and Mandrone (in July and September 2019 and 2020). A risk refinement of chlorpyrifos, calculated using the species sensitivity distribution, indicated an acceptable level of risk, as concentrations were consistently below the effect level. Chlorpyrifos is not the only potential threat to Alpine aquatic ecosystems; therefore, it is advised to continue monitoring other equally potentially dangerous compounds that could reach high-altitude environments through medium-range atmospheric transport. To preserve the ecological and social value of the Adamello-Brenta Natural Park, natural capital is a priority. In this context, the results of this study assume strategic importance in supporting the development of future environmental conservation initiatives and water management policies.