Toxic algae
Blue-green algae are actually microscopic bacteria, called cyanobacteria, naturally colorful. They can be blue-green or reddish brown and float on the surface by forming a layer that thickens over time. Algae eventually dies, replaced by younger. They thrive when it is hot, that there is little rain and wind, and that the water is more than 20 degrees, as currently. They are not algae, and should therefore not be associated with green algae, fatal for humans.
The Flemish Ministry of Health warns: “When the latter die, a toxic substance is released. In the event of contact, they cause all kinds of irritation and health problems.”
Any contact can be dangerous, whether by ingesting water or inhaling what algae emit … namely toxins. “It is not deadly in itself, but it causes considerable discomfort”, add the ministry. In other words, and depending on the degree of contact, diarrhea, vomiting, irritation of the eyes, ears and skin, headache and respiratory problems. In the most serious cases, these algae can cause acute poisoning and lesions to the liver, the kidney, even to the nervous system. Animals are also affected by risks.
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How to guard against it?
It is strongly advised to respect swimming prohibitions, and to check the condition of the water before swimming. And this, everywhere in the country. Blue-green algae were observed in Flanders, in the province of Antwerp. In 2024, 26 prohibitions were pronounced for swimming ponds.
Interactive maps are made available in Wallonia to learn before moving.
