the Olympic triathlon mixed relay event featuring teams of Two Men and two women went forward as planned with swims in the s River elevated levels of bacteria in the water had caused uncertainty over whether swimming in the sen would even be possible but organizers said ahead of Monday’s race that the water quality was acceptable bacteria levels in the water fluctua constantly and daily samples are drawn for testing organizers said they consider water quality analysis sanitary inspection and the weather forecast before deciding whether our race will go forward World Triathlon guidelines for eoli allow up to 1,000 Colony forming units per 100 mL of water ecoli is a fecal bacteria that can indicate sewage in the water caused by Wastewater runoff during heavy rains most strains of ecoli are harmless but some cause gastrointestinal illnesses