The Federal standards for water are much tighter than the standards for Fish which is one part per million (a thousand times higher than the water standard.)

I'm just saying that poisonous isn't just in the compound, it's in the dosage. You can't just freak out because an obviously not dangerous amount of a chemical winds up in the food supply. In that way madness lies.

Plus the form that mercury is in is important. Some forms are easily absorbed by the body, some aren't.