Tokyo Olympics' outdoor swimming venue smells "like a toilet"

• But despite the efforts of organizers — which included dumping 22,000 cubic meters of sand in the bay and designing polyester screens to protect the venue from bacteria — residents have noticed a pungent smell coming off the bay in recent weeks.

By the numbers: Wastewater and sewage from Tokyo's 30 million residents, combined with runoff from multiple rivers and canals, all have to be treated before flowing into Tokyo Bay.

The bottom line: Water pollution is a fact of life for triathletes who compete in events in large cities, which means that arguably the most arduous Olympic event will simply involve a slightly higher — and smellier — degree of difficulty.