The images of the Alps evoke silence, clean air, paths that are lost among woods and rocks. Yet, under the boots of those walking, something is changing. Not spectacularly, not all at once. Plastic does not arrive in the Lombardy mountains by truck or industrial waste. It arrives in pockets, in backpacks, in a snack wrapper opened at the beginning of a hike and then forgotten.
This is not told by a generic complaint, but by scientific research by the University of Milan which for four years has closely observed what remains along the Alpine and pre-Alpine paths. Between 2020 and 2024, researchers traveled 28 routes in Lombardy, collecting and analyzing every visible fragment of plastic. The result is less reassuring than one imagines when we talk about “uncontaminated nature”.
Plastic in the Alps: what researchers found along the Lombardy paths
The investigation covered a wide variety of environments, from the Pre-Alps up to over three thousand meters above sea level. In total, 979 plastic objects were collected, weighing almost four kilos. Numbers which, taken alone, may seem limited. But they become significant if we consider that it is only a small portion of the Lombardy trail network and that we are talking exclusively about visible fragments, larger than five millimetres.
Each object was studied in the laboratory, measured, weighed and analyzed to understand what material it was made of and what its original use was. The plastic found is not an exotic mystery: it is the same one we use every day. Polypropylene, polyethylene, PVC, PET. Resistant materials, designed to last a long time and for this very reason, once dispersed into the environment, they remain.
The most represented category is food packaging. In practice, snack wrappers, disposable packages, bottles. Soon after, fragments of technical clothing, parts of mountain equipment and healthcare products appear. All attributable to local human activities, not to distant transport or contamination brought by the wind from other continents.
Where plastic accumulates and why shelters have nothing to do with it
One of the most interesting aspects of the study concerns the “where”. Plastic does not increase as you rise in altitude and is not concentrated around alpine refuges. It doesn’t even depend, directly, on the number of people walking a path. The researchers compared the data with attendance traces recorded on digital sports platforms and did not find a significant correlation.
However, there is one fact that repeats itself with surprising regularity. Most of the waste is found in the first kilometer of the trails. Then, as you go up, the quantity decreases. It’s a detail that says much more than many awareness campaigns. It means that plastic is often lost or left at the beginning of the hike, when you stop to eat something, when you adjust your backpack, when a wrapper ends up in an external pocket and falls out without anyone noticing.
According to researchers, in most cases it is not intentional abandonment. It’s inattention. But the effect, on the ground, is the same. Some fragments found are already partially buried in the ground, a sign that plastic is not just passing through: it is becoming part of the landscape, with degradation times incompatible with the fragile balance of mountain ecosystems.
What happens to plastic in the mountains
At high altitudes plastic does not disappear. It breaks, fragments, becomes smaller and smaller. Over time it can transform into microplastics, contaminate the soil, end up in waterways, and be ingested by fauna. It is not an abstract hypothesis: it is a process already observed in other mountain and glacial environments.
The study highlights how the Lombard Alps are particularly exposed because they are located near densely populated areas. The mountain, in this sense, is not far from the cities: it is their extension of the weekend. And it is precisely this closeness that makes the problem concrete, everyday, anything but marginal.
The researchers speak openly about the risk of these fragments becoming a sort of permanent repository. A sign left in the ground that tells how we use plastic even where we think we are “elsewhere”, far from the consequences.
Practical solutions
Perhaps the most interesting part of the study is that it does not propose unrealistic revolutions. From the data it emerges that intervening at the starting points of the paths would already be extremely effective. It is there that most of the waste is concentrated and it is there that simple logistical measures can make the difference, such as the possibility of disposing of waste correctly before setting off or avoiding its loss along the way.
In the long term, the issue remains that of disposable packaging, especially food, and the materials used in outdoor products. Reducing plastic upstream, before it even ends up in the backpack, is the path indicated by the authors of the study. Not out of idealism, but because the data shows that that is where most of the observed pollution comes from.
If nothing is done, the researchers warn, the mountains risk slowly but steadily accumulating waste that will remain. There is no need for apocalyptic scenarios: just look at what is along the paths today to understand that the problem has already started.
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