Help me understand:

- water with hexavalent chromium in it is toxic

- these bacteria eat it

- ???

- now the water is non-toxic (or, at least, less toxic)

Why aren't you now drinking water with microbes that have hexavalent chromium in them? Did they bacteria break it down or convert it into different forms that are less toxic? Are the bacteria removed from the water before you drink it (and if so, what becomes of the toxins at that point)?