With the Paris Olympics just three weeks away, recent test results show promising improvements in the Seine's water quality. The river is set to host several outdoor swimming events during the Games.
According to the Paris mayor's office, E.Coli bacteria levels at a key Olympic swimming site in central Paris have remained within acceptable limits for four consecutive days.
Officials attribute this positive trend to recent warm, sunny weather and ongoing efforts to enhance the river's water quality.
This news comes as a relief after last week's concerning reports, which showed E.Coli levels – an indicator of fecal contamination – exceeding acceptable limits daily at the Alexandre III bridge, the starting point for swimming events.
At one point, levels reached ten times the upper limit of 1,000 colony-forming units per 100 millilitres (cfu/ml), following heavy rainfall that caused untreated sewage to overflow into the river.
Seine competitions
The Seine is scheduled to host the triathlon's swimming leg on 30-31 July and 5 August, as well as open-water swimming events on 8-9 August. Enterococci bacteria readings, another crucial water quality indicator, have also shown significant improvement.
Sports Minister Amelie Oudea-Castera expressed optimism about the situation, noting the "clear improvement" and suggesting that current readings bode well for the smooth proceeding of competitions.
In the middle of June, Paris Mayor Anne Hidalgo confirmed that she plans to swim in the Seine in mid-July, with the exact date fixed for a day between 15 July and 17 July, depending on the weather.
Over the past decade, French authorities have invested 1.4 billion euros in river cleanup efforts, including upgrades to Paris's sewerage system and the construction of new water treatment and storage facilities.
However, major storms can still overwhelm the city's aging wastewater network, resulting in effluent discharges into the Seine.
Recent data collected between 24 June and 2 July showed the river was swimmable for six out of nine days across nearly all four sampling locations. This year, Paris has experienced above-average rainfall, receiving 415 mm since January – about 40 percent more than the long-term average.
Additional challenges
While the improved water quality is encouraging, organisers face additional challenges due to increased river flow and height caused by frequent storms in May and June. These conditions have led to repeated postponements of rehearsals for the water-borne opening ceremony scheduled for 26 July.
Last week, the Seine's flow ranged between 400-600 m³/second, significantly higher than the usual 100-150 m³/s for this time of year.
Thierry Reboul, director of Paris Olympic ceremonies, emphasised the need to keep the flow below 500 m³/s. High flow levels could potentially lead to the cancellation of swimming events for safety reasons.
However, Seine Grands Lacs, the organisation managing upstream reservoirs, suggests that sustained dry weather could reduce the flow by 50 m³/s daily.
They also mentioned the possibility of diverting more water into reservoirs, although many are approaching capacity.
As the Games draw near, officials remain cautiously optimistic about the Seine's readiness to host Olympic swimming events, while continuing to monitor water quality and flow conditions closely.
(With newswires)
