Its pretty common knowledge that our oceans are polluted with mercury and other heavy metals. And chollera, seaweed are magnets for heavy metal, you can check mercolas site on chollera(but he recommends chollera for detoxification) but the sad thing is he doesn't recognize the fact that mercury will not be forever held on by chollera and when ingested the body will derive the mercury from the chollera, just like when people get posioned by eating fish.