Although selenium is essential for our health, it must be absorbed in infinitesimal quantities. Our drinking water sometimes contains too much selenium, with little known effects. This is a worrying worldwide phenomenon. This article tells you more about this pollution.

Selenium is a powerful antioxidant, belonging to the group of trace elements that is vital for our body. It helps prevent the development of certain cancers or heart diseases and helps fight against cholesterol or osteoarthritis.

But although it is essential in trace form, the situation is different when its concentration increases. At the European level, its limit value of potability is fixed at 10 micrograms per liter. This is a precautionary value and it is difficult to set a more precise value because there are few epidemiological studies. What we do know is that selenium is toxic at higher doses.

For 20 years, an American biologist studied the disappearance of fish from Belews Lake in North Carolina, which borders a coal-fired power plant. These fish started very early to present important malformations on different parts of the body (skeleton, head, eyes...). 95% of the species disappeared in a few years and more than twenty years later, important concentrations of selenium are still found in the sediments and in the food chain of the surviving fish...

Selenium pollution is insidious because there is no sudden mortality and it often goes unnoticed. It is a geogenic pollutant, that is to say naturally present in the rock and passing in the water during drilling carried out for the capture of the water. It is also an indicator highlighting the use of overly deep groundwater. And this is unfortunately a current trend. Indeed, in order to protect ourselves from the increasing surface pollution, we tend to dig deeper and deeper.

Another source of this pollution could be industrial or agricultural. The storage of burnt coal-based waste could, through leaching, contribute to selenium contamination. In agriculture, the spreading of sewage sludge or the use of selenium-rich fertilizers could be the source of significant pollution.

Selenium pollution is a worldwide phenomenon and the pollution of aquatic environments by this substance is widespread in cities as well as in the countryside, from the plains to the mountains, from the most remote forest to the polar ice caps. Analyses carried out in natural environments are often concentrated on more common and priority pollutants, but this omits the fact that selenium pollution can pose very important long-term risks for aquatic habitats and fishery resources. Biologists' awareness of this pollutant is important because once a natural environment is contaminated with selenium, a cascade of bioaccumulation events follows, making any subsequent intervention almost impossible.
While waiting for a real risk management based on water quality objectives to prevent biological impacts, you can use the Berkey® water purification system which, with the help of its Black Berkey® filters, eliminates more than 99.9% of the selenium contained in the water, as attested by analyses carried out by an independent laboratory