I did not see an amount ...

I did not see an amount listed. As you know arsenic is an essential nutrient.  Responsible for all animal fertility, helps build strong bones in new born babies, very essential for the cardio system, help maintain normal mitochondrial cell membrane function in heart muscle cells.  The health range has been determined to be 12 to 50 mcgs.   Using the Archaea species will lock up any excessive amounts of this nutritional element.  This ancient process has been successful in tying up excessive salts (brine) at drilling site and natural desert brine areas.   Arsenic falls into the category of ice cream.  One ice cream cone in one hour is a desert. One ton of ice cream is a toxin to you.  Chemicals not really needed.  But it does keep people employed.