The heat wave continues to raise the mercury on thermometers in Côte-d’Or. In these conditions, only one desire: to swim to cool off. Even if “here begins the sea” in Dijon, difficult to find a French city further from salt water. So you have to dive into lakes or rivers, and you come up against this question every summer: is the water clean in our department? France Bleu Bourgogne tells you how the quality of bathing water is controlled.
About fifteen bodies of water monitored in Côte-d’Or, checks every 15 days in summer
In Côte-d’Or, there are about fifteen places where swimming is supervised and where the water is analysed. Water quality is measured at least 10 days before opening, then tevery 15 days during the summer. Not all swimming areas open at the same time: on June 11 for example for Lac Kir in Dijon, against July 1 for the beach at Pontailler-sur-Saône.
– Adrian Beria
How is a check carried out?
We followed Anthony Genin, sampler for the Côte-d’Or departmental laboratory, during a sampling on the bathing area of Pontailler-sur-Saône, Tuesday June 14, 2022. Equipped with waders, waterproof overalls that go up up to the bust, it immerses itself in the Saône to reach a depth of one meter. “The most representative of swimming”he explains.
Armed with a sterilized metal clamp using a blowtorch, he will successively fill three plastic canisters. The first is analyzed on site, to measure the saturated oxygen level, the PH (the acidity of the water) and the temperature. The other two cans will then be sent to the laboratory to be analyzed – in particular to detect the rate of Escherichia coli and enterococci, two types of bacteria that can cause illness.
But Anthony Genin’s work does not stop there. On a sheet – which he then sends back to the ARS – he must fill in boxes. Today’s weather, yesterday’s weather, presence or absence of mineral oils, phenols. That day, nothing to report. The sampler also mentions the presence of animals – swans – which could explain the presence of bacteria in the water, if any. He returns one last time to the Saône to measure the transparency of the water using a “Secchi disc”, a disc placed at the end of a rope. The water is rather clear, he notes “one meter”, the maximum value.
To complete his intervention, Anthony Genin must check the cleanliness of the beach, the state of the toilets, and the correct display of the results of the ARS. Sampler’s report : “Green light for me. Then you have to wait for the result of the laboratory to know the quality of the bathing water of Pontailler-sur-Sâone”.
How do I know if I can swim safely?
To know the water quality, you have to go to the map put online and updated over the checks by the Ministry of Health. The water will be either “Excellent” (the maximum score), “Good”, “Sufficient” or “Insufficient” (the minimum score).
Bathing places referenced by the ARS in 2021
- Pont-et-Massene
- Venarey-les-Laumes
- Grosbois in the mountains
- Lake Kir
- Arnay-le-Duc
- Vandenesse-en-Auxois
- Nolay
- Montagny-les-Beaune
- Pagny-le-Chateau
- Magny sur Tille
- Arc sur Tille
- Pontailler-sur-Saone
- Riel the Waters
– ARS BFC