Water pollution made international headlines this week when the swimming leg of the Paris Olympic men’s triathlon was postponed a day because of high E. Coli counts in the River Seine. Later in the week, Belgium withdrew its team from the mixed relay triathlon, and Switzerland had to change its roster after two athletes became sick with an unspecified illness.
Called a “bold gamble” by Anne Hidalgo, the mayor of Paris, scheduling the men’s and women’s triathlon swimming competition in an urban river was a departure from past practice. Concerns about the Seine’s fluctuating pollution levels were significant enough that the mayor took a much-publicized dip in the river before the Olympics began.
For decades, the river has been the dumping ground of Paris, and swimming in the Seine has been illegal for a century. The major pollution source in recent decades has been runoff of contaminated stormwater and direct discharges of sewage.
A billion dollar-plus infrastructure program has increased the diversity of aquatic life in the river, and there are hopes of opening public swimming spots next summer. But the Olympic postponement showed there is more work to be done.
The World Triathlon organization rules state that if E. Coli levels are above 1,000 CFU/100mL, the swimming leg must be canceled. Here in Michigan, EGLE recommends no bodily contact above the waist (i.e. swimming) when E. Coli levels exceed 301/100mL. When E. Coli levels exceed 1,000/100mL, EGLE recommends no bodily contact at all. In other words, Michigan’s water quality standards for swimming are considerably higher than the Worth Triathlon organization’s standards for its athletes.
A microscopic look of the e. Coli bacteria.
So what would happen if a city in Michigan was selected to host a future Summer Olympics or international triathlon event?
What if the swimming portion of the Olympic triathlon were held in an urban river in Michigan?
It would depend on the weather.
The chief urban threat to the water quality of many Michigan waters is the release of sewage from combined sewer systems. Such systems mix sanitary and storm sewage, like the system in Paris, and heavy rains or snowmelt can overwhelm the capacity of treatment plants, which then bypass the waste into rivers.
In 2021, the last year for which the state Department of Environment, Great Lakes and Energy has posted data on sewage overflows, a single (record) storm of 5-7 inches of rain in southeast Michigan led to the release of 3.27 billion gallons of sewage. Such intense storms and resulting combined sewer overflows are increasing because of climate change.
In 2021, there were 383 overflows, releasing 46.74 billion gallons of untreated or inadequately treated sewage to Michigan waters. The state is working with local governments to do away with the approximately 90 overflow points in 40 communities in Michigan rivers. In the Great Lakes as a whole, 158 communities have permits allowing overflow discharges.
Following the Paris example (minus the e. Coli, they hope), organizers are planning a Chicago River swim in September. Although the river has been classified as acceptable for swimming by environmental agencies, Chicago’s sewage system is designed to shunt overflow sewage away from the lake and down the Chicago River.
The August 24-25 Chicago Triathlon includes a 1500-meter swim in Monroe Harbor in the city’s Lake Michigan waters. Chicago’s sewage overflows occasionally and are so great that they affect Lake Michigan as well.
Professional athletes finish a marathon swim
