A pink lake it is not something exceptional. In fact, there are several in the world. The best known is the Retba, from Cape Verde, although there are also others in countries like Azerbaijan or Canada. In general, the reason for their coloring is completely natural, as it is due to the presence of certain algae, bacteria and small crustaceans. However, the case of the pink lagoon of Patagonia, in Argentina, it is very different.

This time its color is not due to the inhabitants of its waters, but to the residues released by a fish farm close. Specifically, the cause is the sodium sulfite, a compound that is used to preserve shrimp that will be transported for sale from bacterial contamination.

Residues of this substance, as well as fish and shellfish treated with it, are released into the Chubut river, whose water flows to places like the Corfo lagoon. Neighbors near it saw it turn pink last week. He stayed like that for a few days and then returned to his usual tone. It is not the first time that it happens, but they begin to be fed up. This is what we know at the moment about this curious situation.

A flashing pink lagoon

The residents of the towns near this pink lagoon do not only complain about the color of the water. They have also been protesting for a long time rotten smell that comes from them, possibly from the remains of fish that are released into it.

But, without a doubt, the situation becomes more extreme when the lagoon is stained, because the problem is much more visible. As explained in a statement from Agence France-Presse issued by Science Alert, the inhabitants of Rawson, one of the towns near the pink lagoon, have come to meet on the roads to block the passage of trucks loaded with the remains of fish from the fish farm. However, the head of environmental control of the province of Chubut insists that the sodium sulphite discharges are harmless, so the company continues to have permission to dump the fish remains there, despite the fact that there is a plant treatment 56 kilometers away.

On the other hand, environmental activists they maintain that something so serious should not be minimized.

Is Sodium Sulfite Toxic?

Sulfites in general, including sodium sulfite, are commonly used in food as antimicrobial additives. For example, it can be found in wines, beers, pickles, dried fruits or egg products.

Sulfites are widely used as antimicrobials in food

Like other additives, they are quite demonized. In fact, it is quite common to find the claim “sulfite free” on products like beer. It is paradoxical, since alcohol is much more harmful than sulphites; Well, at the doses used, they are harmless.

That is the first thing we must take into account, therefore, when talking about sodium sulfite. In the doses used in food does not pose a danger.

However, if we look at the security file of this chemical product, we will see that if it is ingested directly or comes into contact with the skin or mucous membranes, it can be very toxic. Therefore, when evaluating whether it is toxic in the pink lagoon of Argentina, measure doses in which it is released. In the same safety data sheet it is also mentioned that it is commonly used as an wastewater dechlorination and that, therefore, it is not dangerous at the level of ecotoxicity. But it is explained that a very high concentrations increases the demand for chemical oxygen in aquatic environments. It is also noted that his biological degradation is very fast. This is possibly why the color of the water changes so quickly.

Ultimately, a exhaustive analysis of the waters of the Laguna Rosa Argentina to determine if an environmental hazard exists. Changing color of the water is a good indicator that high concentrations of this substance are building up. But it would be necessary to know more. Of course, if there is a treatment plant nearby, it is a good option to consider.