The bubbling was only short-lived.
At the Etangs de Hollande leisure center, located in Les Bréviaires, very close to Rambouillet (Yvelines), the red flag has been hoisted again since Monday.
And this, until further notice.
The ban concerns swimming and aquatic activities, due to the excessive presence of cyanobacteria in the water.
The other activities offered by the site, such as minigolf or beach volleyball, however, remain accessible.
Swimming had however been authorized for a few days, from July 27 to 31, after a two-week ban.
The Regional Health Agency (ARS) does, in fact, take readings in the water at the start of each week.
Between July 13 and July 27, the authorized threshold of cyanobacteria had been "exceeded by more than 100 times" then lamented Thomas Gourlan, president of the Rambouillet Territoires agglomeration community which manages the site.
A fertile ground for the proliferation of cyanobacteria
It must be said that the ponds of Holland are particularly conducive to the proliferation of cyanobacteria, sometimes mistakenly called blue algae.
Artificially dug in the 17th century to supply the basins of the Palace of Versailles, these lakes are not fed by any river.
Their water can therefore only be renewed by rain.
Cyanobacteria multiply in standing water when temperatures rise and rainfall decreases.
Toxic, they cause skin irritation, but also stomach aches and nausea if ingested.
They can especially be fatal for dogs and aquatic animals.
It is therefore also forbidden to consume fishing products from the ponds of Holland, specifies the decree of the town hall of Les Bréviaires.
