No, its not. Just another one of those click-bait “science” sites I wish I could block from my feed.
It’s just iron stained water – like every other iron stained water body in the world. Probably has a pretty low pH too.
Did you know that the mining mega-corporation named “Rio Tinto” refers to the red water at a naturally flowing river in Spain? They’ve been mining metals there forever – https://en.wikipedia.org/wiki/Riotinto-Nerva_mining_basin#From_Antiquity_to_the_Middle_Ages
My guess was gonna be cinnabar.
That would fail Occam’s Razor. Furthermore, the article talks about iron.
Cinnabar is actually super rare. I’ve spent half my life doing mineral exploration and have never seen it in the wild anywhere. I’ve only ever seen samples in the lab or in a museum.
Same for the Eau Rouge (French for red water), iron rich stones.