What is hidden in the snow?

Once we get the winter fluff, then in the media there are messages “under no circumstances eat snow”, “snow can be dangerous – do not eat it”. When can water vapor particles, forming ice crystals, be dangerous? Of course, the answer is simple – when they are contaminated. “Pure” are completely harmless. However, there are few places in the world where the snow has remained pristine. Typically, as a result of increasing anthropogenic pressure on the environment, it contains a number of hazardous substances.

Snow as an absorber

Snow can act as a sink for various pollutants, including heavy metals, organic compounds and acidifying compounds. This process is known as “dry deposition” because it occurs as a result of particulate matter and gaseous pollutants falling to the surface of the snow rather than as a result of precipitation or runoff.

One of the key factors affecting the absorption of contaminants by snow is its chemical and physical properties. For example, some heavy metals, such as lead and cadmium, can easily penetrate the snowpack. The situation may be different with organic compounds – they are more difficult to absorb.

Another important factor is the structure and properties of the snowpack. For example, fluffy snow has more surface area per unit volume than denser snow, which can make it more effective at absorbing pollutants. In addition, the rate of snowfall, temperature and weather conditions can also affect its ability to adsorb contaminants.

What will the snow fall on?

There are many potential sources of hazardous substances that can be found in snow. It only needs to fall in an area with industrial pollution, and it can collect small amounts of toxic chemicals or heavy metals. Likewise, if the snow melts and then refreezes, it may contain dissolved contaminants that are then trapped in the ice.

Another potential source of hazardous substances in snow is de-icing chemicals, which are often used to melt snow and ice on roads, bridges or sidewalks. These substances may include sodium chloride, calcium chloride and magnesium chloride. In addition, anti-icing chemicals and fertilizers used in nearby agricultural or residential areas also cause pollution.

Another problem with snow is that it can contain bacteria and other microorganisms. In colder climates, a layer of snow lingers on the ground for months, creating a breeding ground for bacteria, viruses and other microorganisms.

In most cases, pollutants harmful to humans and animals, when the snow melts, are discharged into groundwater, with time into groundwater or watercourses, without any treatment.

Is there anywhere in the world where the snow is clean?

There are regions of the world that are known for relatively clean snow, such as the polar regions (Antarctica and the Arctic) and high-altitude mountain ranges, such as the Arctic. Himalayas. In these areas, there is very little direct human activity, so there is less likelihood of snow contamination, although, as studies show, this is not so obvious.

Global pollution problems and climate change are affecting snow even in inaccessible areas of the Earth. An example is the confirmed presence of microplastics in Antarctica (pieces of plastic smaller than 5 mm in size, which can come from various sources such as garbage, cosmetic products, synthetic clothing, etc.).

The presence of plastic microplastics in Antarctica is particularly worrisome because it is one of the most remote and pristine regions on Earth. The continent is surrounded by ocean currents that can pick up pollution and accumulate it in some areas. Studies have found plastic contamination in the air, water and even ice and snow in Antarctica. They have also been found in the stomachs of marine animals, such as krill, which are a key part of the food chain.

It seems that it is mainly the wind that brings microbeads of plastic to Antarctica. He collects them both from other lands and from the oceans. Studies have shown that they come from even as distant sources as urban areas in South America and Africa. Their presence is a cause for concern because they can have a negative impact on the continent’s fragile ecosystem, can seriously disrupt the food chain and act as a vector for other pollutants and invasive species.

So, completely clean snow is unfortunately already a huge rarity, even on a global scale. Something that seems obvious and natural is no longer so.