The Berkey PF-2 filters reduce fluoride and arsenic in your water using the media aluminum oxide (aka activated alumina). As a consumer, it’s important to know that pure aluminum and aluminum oxide have vastly different characteristics. Pure aluminum is water-soluble, it is highly reactive and it is associated with negative health effects. By contrast aluminum oxide is not water-soluble; it is inert, is very stable and is not associated with negative health effects. Confusing the two is similar to saying that salt is bad for you because it contains chlorine (NaCl) or is explosive because it contains sodium. When in the form that it is in, it has very different chemical properties.
That then raises the question, do the Berkey filters leach aluminum into the drinking water? The answer to that is, NO! You can read more about all of this in the paper published by the manufacturer below.