Seine River Cleared for Olympic Triathlon Despite Water Concerns

After delays due to elevated bacteria levels, the Seine River will host the men's and women's Olympic triathlon races. The races were postponed amid efforts to ensure water quality met safety standards. Officials invested €1.4 billion in infrastructure improvements to clean the Seine, and latest tests confirm compliance with quality standards.

After days of delays over concerns about water quality in the Seine River, the Olympic triathlon races will proceed Wednesday with a swim in the iconic Paris waterway.

The decision is a major win for the city, Olympic organizers, and athletes. Officials invested €1.4 billion in infrastructure to clean the Seine, insisting it would be safe for both the triathlon and next week's marathon swimming events.

Latest tests, as of early Wednesday, confirmed the water meets quality standards. Elevated bacteria levels had postponed the men's race, initially scheduled for Tuesday, to Wednesday, the same day as the women's race. Rainfall had exacerbated wastewater runoff into the river, complicating efforts to maintain water quality.

High levels of E. coli, a bacteria indicating sewage contamination, were a primary concern. While most E. coli strains are harmless, some can cause serious illness if ingested through contaminated water. Water quality tests measured fecal bacteria levels, with safe swimming conditions set at below 900 colony-forming units per 100 milliliters.

Despite uncertainties, confidence remained high among organizers, even as they withheld detailed public data on bacteria levels. Results indicated some test sites were near acceptable thresholds, and organizers hoped that recent heat would improve water quality.

The marathon swimming events could be moved to another venue if needed. Significant investments included a basin to manage rainwater, infrastructure renovation, and wastewater treatment upgrades. Paris Mayor Anne Hidalgo and other officials recently swam in the Seine to demonstrate their confidence in the river's safety, though data showed E. coli levels slightly above the threshold.