A tropical storm heading for Tokyo could leak sewage water into the Olympic triathlon swimming course

• A tropical storm headed for Tokyo could leak sewage water into the Olympic triathlon swim course.
• In parts of Tokyo, there are not separate drainage systems for rainwater and sewage.
• A 2019 paralympic test swim in Tokyo was cancelled because of E. coli, but officials believe there are enough measures in place now to stop sewage.

Olympic officials are confident that safety measures put in place will stop a tropical storm heading for Tokyo from leaking sewage water into Tokyo Bay, where the Olympic triathlon swimming will take place.

The storm is expected to hit Tokyo on Tuesday. The men's triathlon is scheduled for Monday. The women's is scheduled for Tuesday.

According to Reuters, many places in Tokyo don't have separate drainage systems for rainwater and sewage. A city official told Reuters that there are systems in place to separate it where the triathlon swim takes place, however.

A paralympic test swim was cancelled in 2019 because of dangerous levels of E. coli in the water. In 2015, multiple analyses of water quality found high levels of dangerous drug-resistant "super bacteria" from human sewage that threatened the 2016 Olympics.

It's been reported that the Tokyo Bay, which experts have said still might contain dangerous levels of E. coli, has been known to "smell like a toilet."

Olympic officials stressed that there are protections in place to prevent sewage from leaking into the course.

"We have installed triple-layer screens as a measure to help ensure water quality," a spokesperson told Reuters. "As well as thereby preventing the inflow of E.coli bacteria after rainfall, through daily monitoring of water quality and the weather we aim to stabilize water temperature by opening the screens during periods of fine weather when water quality is stable.

"Furthermore, water flow generators have been introduced to deal with rising water temperatures when the underwater screens are closed."

According to Reuters, since 2019, 22,000 cubic meters of sand were placed in the bay to create an environment to support organisms to help clean the water. The screens were also installed.

However, Yukio Koibuchi, a former associate professor at Tokyo University's Graduate School of Frontier Sciences, told Bloomberg earlier in July that the screens may not help much because bacteria could flow underneath the screens.

Hugh Robertson, president of the British Olympic Association, told Reuters he doesn't currently have any concerns about the water quality, saying the polluted water in Rio was a bigger concern in 2016.