PARIS (AP) — A test run meant to allow Olympic athletes to familiarize themselves with the marathon swimming course in the Seine River was canceled Tuesday over concerns about water quality in the Paris waterway.

Paris 2024 spokesperson Anne Descamps confirmed that World Aquatics made the decision to cancel the exercise.

The cancellation comes a day after the triathlon mixed relay event was held in the river that runs through the center of the French capital. The portion of the Seine in which the triathletes swam is much shorter than the course for the marathon swim, which has races scheduled for Thursday and Friday.

World Triathlon released data Tuesday showing that when the triathletes swam Monday, the levels of fecal bacteria E. coli and enterococci were within acceptable levels.