[shafaifer]

Isn't true iron can make compounds/complexes with heavy metals when it has the oxidation state, +2? Assumption: When it is oxidised to Fe³⁺ the heavy metal will mobilize and no longer be part of the complex with iron as it is seen with acid mine drainage, according to my assumption.   

[Arkcon]

You're going to have to give us an example of what you're talking about.  Iron is already a metal.  A complex would involve non-metals, or complex ions, or organic compounds, which may contain other metals.  But a complex of iron and another metal isn't a complex -- its an alloy.

[shafaifer]

I do sorry for not being specific:

I was told by my teacher that heavy metals can bind to iron hydroxides. So my question is, for a heavy metal to bind an iron hydroxide, iron must/often have the oxidation state of +2 - that is my question and that is my assumption.