a month and a half before the tests, there are still too many fecal bacteria in the Seine – Libération

Despite these poor results, due to the rains and storms of recent days, the prefect of Paris Marc Guillaume says he is “confident about the holding of the tests”.

The Seine still far from being healthy. A month and a half before the Olympic events which are to be held in the river, it displayed pollution levels well above regulatory standards. The fault is gloomy weather which is not over, according to the forecasts. The rains and storms of recent days in Ile-de-France left little room for suspense. The water quality bulletin published this Friday, June 21 by the local authorities confirmed it: a few days before the start of summer, the Seine remained unsuitable for swimming.

According to the graphs posted online, almost every day from June 10 to 16, the level of concentration of fecal E.Coli bacteria was greater than 1,000 colony forming units (CFU)/100 ml (the threshold retained by the international federations triathlon and open water swimming to authorize the holding of events). The cause: “very rainy weather” leading to “the high flow of the river, which does not promote good water quality”, explain the Paris town hall and the regional prefecture.

“Rain, high flow, little sunshine, temperatures below seasonal standards” form an “unfavorable hydrological and meteorological context” which explains that “the quality of the water remains degraded”, they recall again. These two institutions are at the head of the Bathing Plan, in which the State and communities have invested 1.4 billion euros to make the Seine and its main tributary, the Marne, suitable for swimming. But if this plan “arrives successfully”, “there is no doubt that the quality of the water today is not there”, recognized the regional prefect Marc Guillaume during a press briefing on the Olympics, which start on July 26.

The prefect still “confident about the holding of the tests”

The samples published on Friday “do not correspond to the standards that we will have this summer,” he then said. “As soon as the conditions are met, the plan will be able to produce all its effects,” assured the senior official, “confident that the tests will be held at the end of July and beginning of August in the Seine.” Time is running out for the organizers, and the weather forecast for the next two weeks does not give cause for optimism, with generally rainy weather until July 5, according to Météo France.

Suddenly rising on Friday, to more than 500 m³/second, compared to around 300 the previous week, the flow of the river poses not only a problem for the quality of the water, but also for the safety of the events. Even for the opening ceremony on July 26, an unprecedented nautical parade on the Seine, a general rehearsal of which is to be held on Monday.

The last partial rehearsal, finally organized on Monday, had been postponed for several months. “If we have too much flow, it poses a serious problem for the opening ceremony,” said hydrologist Jean-Marie Mouchel in a reaction to AFP. Contacted by the press agency, the Organizing Committee (Cojo) said it had “no particular concerns”.

Waste

Star of these Olympics, the Seine will host the opening ceremony as well as the triathlon events (July 30 and 31, August 5), swimming-marathon (August 8 and 9) and paratriathlon (September 1 and 2). But suspense remains over the holding of the Olympic events since the “test events” of August 2023 which had to be largely canceled due to insufficient water quality.

Plan B consists of postponing the tests for a few days, but not changing location. Before that, the mayor of Paris Anne Hidalgo announced on Wednesday that she would swim to set an example “after July 14, that is to say the 15th, 16th or 17th”. The original date, June 23, was abandoned due to bad weather and early elections.

In the event of intense precipitation, untreated water – a mixture of rain and wastewater – can be released into the river, a phenomenon that retention works inaugurated just before the Games are intended to prevent. The Austerlitz retention basin also operated for the first time on Tuesday during a big storm, receiving 40,000 m³ of water out of a capacity of 50,000, the town hall indicated on Wednesday.