An audit of the quality of bathing water in the Gulf of Saint-Tropez carried out during the summer

Every year, this summer problem resurfaces and worries holidaymakers looking for a refreshing break on the Gulf's beaches. Last weekend, the Croisette municipality imposed a new swimming ban after non-compliant test results on the D-Day landing beach .

" From June 1st to September 30th, we take daily water samples from the 43 sites in our territory to detect the presence of several bacteria ( Escherichia coli and fecal enterococci, editor's note). Once collected in a bottle, we analyze the substance in our laboratory before communicating the information to the municipalities concerned, 24 hours later ," simplifies Quentin Langevin, responsible for bathing water quality at the Community of Communes (Comcom'). This self-monitoring system is certified " Bathing Water Quality Approach " at the national level.

New tools to target sources of pollution

To maintain this certification for as long as possible, an audit is conducted every year by an accredited body. " Its objective is to ensure that the Comcom' and the municipalities meet the requirements of the bathing water quality standard," Jenny Debaere clearly defines.

For a week, this audit manager at ÆS certification—a consulting firm based near Bordeaux—observed and noted the actions taken by local authorities to ensure the safety of swimmers. Four municipalities were involved in this audit procedure: Saint-Tropez, Cavalaire, Gassin, and Cogolin.

" The sites examined change every year . I particularly observe the application of the procedure and the corrective actions that are carried out to manage a crisis when the results are non-compliant," she explains, before mentioning a second important criterion. " I also check the identification of the anomaly, its traceability and the solutions provided."

To fill this gap, several measures have been implemented in recent months, starting with the installation of a private computer network to archive all previous sources of contamination. A current study was also launched last August, off the D-Day landing beach, to study the impact of the position of the Pardigon wastewater treatment plant's discharge into the sea.

Recently, the Maritime Spaces Department awarded a new contract to collect environmental DNA samples. These experiments began a few days ago. " This approach allows us to identify the source of contamination more quickly. We will then be able to determine whether the cause is human or animal by specifying the species. It's a real time saver," explains Quentin Langevin.

94% of results compliant

Once the field survey was completed, the bathing water quality managers from the municipalities studied were invited to attend the audit's conclusion. The manager outlined the key points, suggestions for improvement, and observations.

The immediate availability of results, the diligent monitoring of anomalies, the posting of an explanatory video on the community site, the complete review of the season and the actions undertaken in 2024 were praised by the expert.

" Regarding the measures to be improved , it might be necessary to have more developed surveillance management on the seasonal wings. In other areas, several communities are already thinking about extending the surveillance period so as not to limit it to the summer period, she suggests. Thematic or sector meetings could be initiated between seasons in order to have more smooth monitoring over time. These discussions would make it possible to find new improvement actions for beaches that have similar profiles ."

Finally, the manager recalled the percentage of analysis results from the previous season. In 2024, 94% of them were compliant out of nearly 1,500 samples.