Worries over Proliferation of Cyanobacteria in Lakes of Bois de Vincennes
Promenaders and pet owners are concerned about the proliferation of cyanobacteria in the lakes of Bois de Vincennes. The city of Paris seeks to reassure.
For several weeks, regular visitors to Bois de Vincennes have been concerned about the proliferation of cyanobacteria in the bodies of water, especially the lake of Saint-Mandé.
“These microscopic organisms color the water green,” explains Tangui Le Dantec, scientific advisor for France nature environment, on BFM Paris Île-de-France.
A danger for the fauna
This multiplication of cyanobacteria leads to a significant decrease in oxygen levels in the water, resulting in the death of fish. “That’s the case here, there are no more fish,” affirms Tangui Le Dantec.
This high concentration of cyanobacteria can also pose a danger to animals that swim in the water, especially dogs, as well as children.
“When it’s hot, I’ve seen children put their legs in the lake. It’s terrible that we are not informed,” worries Juliette, a walker.
Conducted analyses
The city of Paris, contacted by BFM Paris Île-de-France, indicates that it has been “alerted to the situation,” as has the town hall of the 12th arrondissement. It explains that “the ecological situation of the bodies of water is closely monitored by the agents of Bois de Vincennes and by associations for the protection of aquatic environments.”
According to the city, “no mortality of fish, birds, or other animals has been observed” on site.
On the other hand, the neighboring department of Val-de-Marne regrets the lack of communication regarding this possible pollution episode, especially to the walkers of Bois de Vincennes. “Sometimes, we are informed and sometimes we are not, as is the case here,” regrets Déborah Münzer, vice-president of Val-de-Marne.
“You just informed me, I will tell the other walkers,” reacts a local resident on BFM Paris Île-de-France. If no signage has been posted yet, it is because the city is waiting for the results of the analyses requested from Eau de Paris in order to determine if the presence of cyanobacteria is confirmed.
The heatwaves to blame
This proliferation is linked to the heatwaves of recent weeks in the Paris region, which have led to an increase in the temperature of the bodies of water.
Other municipalities have already been affected, including Créteil in mid-August, where water activities were suspended on the lake due to cyanobacteria.
“This is in no way related to maintenance or management choices for these bodies of water, but rather a consequence of climate change,” insists the city of Paris. To limit these effects, the municipality states that it has already added water to the affected bodies of water to re-oxygenate them.
Nicolas Dumas and William Helle with Amaury Tremblay
