Paris, France - The river Seine is still failing water quality tests one month before the Paris Olympics when it is scheduled to host the open-water swimming competition and the swimming leg of the triathlon, results showed Friday.

The latest tests, completed last week and released by the Paris mayor's office, showed levels of the E.Coli bacteria – an indicator of fecal matter – are far above the upper limits imposed by sports federations.

On June 18, the level of E.Coli was 10 times acceptable levels and at no point did it fall below the upper limit of 1,000 colony-forming units per 100 milliliters (cfu/ml) used by the World Triathlon Federation.

The readings for enterococci bacteria were better, but they were still at unsafe levels for three of the seven days of last week.

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"Water quality remains degraded because of unfavorable hydrological conditions, little sunshine, below-average seasonal temperatures, and upstream pollution," the mayor's office said in a statement.

French authorities have spent 1.4 billion euros ($1.5 billion) in the last decade trying to clean up the river by improving the Paris sewerage system, as well as building new water treatment and storage facilities.

But major storms still overwhelm the capital's wastewater network, some of which date back to the 19th century, leading to discharges of untreated sewage directly into the river.

After months of unusually wet weather, the Seine is currently high up its banks, with its flow around four to five times higher than its usual level in the summer months, according to recent readings.

Organizers insist that some dry weather and sunshine in the coming weeks should be sufficient to make the Seine fit for the outdoor swimming events.

The high water levels and rain are also disrupting preparations for the opening ceremony which is set to take place on the river on July 26.

For the first time for a summer Olympics, the Games will begin outside of the main stadium, with athletes set to sail six kilometers (four miles) down the famed waterway on nearly 100 river boats.

But with currents unusually strong, organizers canceled the first full practice session for the ceremony on Monday.

Paris mayor Anne Hidalgo, who wants to create public swimming spots in the river next year as part of the Olympics legacy, also had to postpone a planned dip to demonstrate its cleanliness last weekend.

She has promised to take to the water during the week of July 14 instead.

Constantly asked about contingency plans if the Seine remains too dirty and turbulent once the Games begin, Paris 2024 organizers publicly insist there are no alternatives to their plans.

Behind the scenes, however, sources have told AFP that the opening ceremony can be scaled back and could even become a much-shortened parade over a bridge in front of the Eiffel Tower.

For the open-water swimming, organizers have flexibility in the schedule, enabling them to delay the competition for several days in the event of a downpour that would lead to a spike in pollution.

In the worst-case scenario, it would be canceled.