We are heading for a few warm days. And what could be better than taking a refreshing dip. But if you go swimming, you should watch out for blue-green algae. What exactly is blue-green algae and what are the dangers?
1. What is blue-green algae?
Blue-green algae are bacteria that behave like plants, explains blue-green algae expert Miquel Lurling of Wageningen University. Blue-green algae can occur in all types of water and live on light, carbon dioxide and in the water dissolved nutrients. The color of blue-green algae varies from blue-green to red-blue.
2. How is it expanding?
Massive growth of blue-green algae not only causes nuisance, but also health risks. According to Lurling, blue-green algae can multiply strongly, causing a floating layer of blue-green algae to appear on the water. Multiply gThis happens fastest in warm water, when there is little flow and the water contains a lot of nutrients.
3. When is it dangerous?
Not all blue-green algae are poisonous, because not all species can produce toxins, explains Lurling. “However, the distinction is difficult to make. This requires extensive research.” In the Netherlands there is a special Blue-green algae protocol. This protocol states how swimming locations can best check for blue-green algae and what measures must be taken.
A warning is issued in the following three situations: “When a thick floating layer of blue-green algae can be seen on the water, the so-called pigment measurement – a measurement that determines on the basis of light signals whether the blue-green algae is harmful – exceeds certain values and when a specific type of blue-green algae is common.”
However, according to Lurling, there is a lot to criticize about the control. For the time being, the water managers in the Netherlands are not carrying out any toxic measurements. A missed opportunity, according to the expert. Correct measurement makes it possible to estimate the hazards even better. “Technically it is possible, but I think the need has yet to reach the water managers. We as experts have been arguing for this for years.”
4. Which complaints can be caused by toxic blue-green algae?
The severity of the complaints is strongly related to the types of toxins that are present and how much blue-green algae has entered. “But you can get skin rashes, inflamed eyes and stomach and intestinal complaints. Blue-green algae with many nerve toxins can also lead to paralysis symptoms.” According to the expert, no people have died from blue-green algae in the Netherlands. Abroad, yes.
5. What should you do if you have come into contact with blue-green algae?
The chance of becoming seriously ill or dying after contact with blue-green algae is not very high in the Netherlands. According to Lurling, this is because of our clean drinking water. “We never receive very large quantities.” According to Thuisarts.nl, complaints of skin, eyes and intestines last usually 2 to 3 days. But it may even be over sooner. However, it is important to always pay close attention.
View on the map below where you can swim safely.
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