Video: A Japanese river has turned green, and it's not clear why. City authorities in Ikoma, Nara prefecture have warned residents living near the Mochi River not to touch or use the water until experts conduct safety tests. pic.twitter.com/2A9DX6QQ0w— Jeffrey J. Hall 🇯🇵🇺🇸 (@mrjeffu) July 5, 2023
The Tatsuta River is believed to have turned green because someone dumped a component of coloring agents used in bath salts that's said to be harmless.
The Okinawa port turned red because supposedly harmless food coloring dye leaked from a brewery.