we explain to you why the water of the Lac de la Ramée, prohibited for swimming, is taken for public consumption
While the Lac de la Ramée in Toulouse is prohibited for swimming due to the presence of cyanobacteria, the Haute-Garonne prefecture has given an exemption for the water to be taken to supply the public network. Why ? And are there any risks for human consumption? We answer you.
The Lac de la Ramée in Toulouse is still prohibited for swimming. On August 5, the town hall decided to extend the ban on the body of water until further notice due to the presence of cyanobacteria. Algae that can pose a danger to human and animal health.
Despite this ban, the services of the prefecture of Haute-Garonne took an authorization to authorize water withdrawals intended for human consumption. Contacted, the prefecture explains that if necessary, exemptions are taken each year to authorize drinking water producers to take water at a temperature above 25°C under the control of the specialized services of the Regional Agency. health. But should we worry about health?
Dangerous algae for humans and animals
When they proliferate, cyanobacteria can cause vomiting, weakness, skin irritations, conjunctivitis, headaches, dizziness and even beneficial effects for the nervous system.
Several factors favor their proliferation: the temperature of the water, the sunshine or the stagnation of the water. With the heat wave that hit the Toulouse region this summer, all the conditions are in place for the population of cyanobacteria to swarm in Lac de la Ramée.
Samples to compensate for the lack of water
The hydrological situation in France is worsening and the Garonne basin is not spared by the current drought. The persistence of very dry weather gradually put pressure on the Garonne and its tributaries to reach its climax at the end of last week.
The water produced and distributed by Eau de Toulouse Métropole comes from three factories located nearby, Pech David, Clairfont and Tournefeuille. The latter is fed by the Saint-Martory canal (fed by the waters of the Garonne) and the Lac de la Ramée if necessary. It produces 37,500 m3 per day. The historic shortage of water thus forces services to use this resource despite the presence of cyanobacteria.
The extent of the Ramée represents 1.5 million m3 of water. A gigantic tank cannot do without the metropolis. “It is an essential backup resource for Toulouse’s water supply” explains Juliette Wilhelm, executive coordinator of the water and health unit at the Regional Health Agency.
To allow the water from La Ramée to be consumed in complete safety, it undergoes several treatments and filtrations before leaving the tap. The ARS wants to be reassuring.
Clarification and oxidation treatments carried out in the Tournefeuille plant reduce the presence of cyanobacteria.Juliette Wilhelm, ARS Occitanie Water and Health unit coordinator
The regulatory quality limit currently in force in mainland France for raw water used for the production of water intended for human consumption must not exceed 25°C. Or, the water of Lac de la Ramée is currently over 28°C. Degrees which do not prevent the samples but which push the competent services to multiply the controls. According to the prefecture of Haute-Garonne, the monitoring of water quality indicators and the treatment of drinking water are reinforced.
The latest research carried out at the Ramée water intake has shown the absence of toxins.