A research team led by the Eco Research Center in Bolzano analyzed water from 80 high-altitude springs located in various mountain ranges of the Central-Eastern Alps. The analyses revealed that, in valleys with certain, very common types of rock, springs originating from permafrost and glacial areas are characterized by high levels of heavy metals such as nickel, manganese, and aluminum. Specifically, in 36% of the springs investigated, the concentrations of these substances exceeded the limits set for drinking water by European Union and Italian regulations.

As revealed by the study, recently published in the Hydrological Processes journal, the phenomenon affects springs fed by various landforms that also serve as important Alpine water resources, namely glaciers and rock glaciers, recently formed moraines, and talus slopes. And this is a new finding. Until now, in fact, most research had focused only on rock glaciers and, to a lesser extent, on glaciers. The results of this new study, therefore, demonstrate that heavy metal contamination of mountain waters is more widespread than previously thought.

“Heavy metal contamination of high-altitude waters is related to both the geology of the area and the degradation of the cryosphere – that is, the loss of glaciers and permafrost,” explains Stefano Brighenti, a researcher at Eco Research and the study’s lead author. “Ice acts as a barrier where chemical reactions are inhibited. When the volume occupied by ice decreases, water from rain and melting snow penetrates deeper into the ground or flows through areas rich in rock material which have recently been broken down by the action of glaciers and permafrost. Water and oxygen, therefore, interact more with mineral surfaces, increasing the water’s acidity and leading to the release of heavy metals from the rock. Consequently, spring water has higher content of these substances.”

“This study is important because it demonstrates that where the cryosphere degrades, it is highly likely that water sources will be contaminated,” says Chiara Crippa, the study’s second author and a researcher at the Institute for Earth Observation at Eurac Research in Bolzano. In fact, the study found that, at sites characterized by sulfide-rich rocks, the only springs with good-quality water are those originating from non-glacial structures which have not been affected by permafrost and which usually flow from slopes rich in soil and vegetation.

The ongoing climate crisis is expected to exacerbate the phenomenon of water contamination. Rising global temperatures, in fact, are accelerating the degradation of permafrost and the retreat of glaciers, facilitating the large-scale release of heavy metals into Alpine waters. “We must prepare for a future characterized by increasingly scarce and, in vast areas, increasingly polluted mountain waters. With increasingly evident ecological, social, and economic effects even in downstream areas,” says Brighenti.

The research was conducted as part of Tiomi NOI Capacity Building II, funded by the Autonomous Province of Bolzano. It involved the collaboration of numerous research institutions: the Free University of Bozen-Bolzano, Eco Research, Eurac Research, the Edmund Mach Foundation, Muse – Science Museum of Trento, the University of Padua, the University of Turin, the Austrian Academy of Sciences, and the Adamello-Brenta Nature Park.

Link to the study: https://onlinelibrary.wiley.com/doi/10.1002/hyp.70515