Point of trivia - I think the isolated Selenium is not literally a heavy metal but I understand the association with the toxicity and endurance attributed to heavy metals. I call Selenium a semiconductor - I can't remember what that group is called in the Periodic Table..Transitional?
So, what happens to photos that one tones with selenium toner? Are they then bad news to have around? I haven't heard that yet.
How long does Kodak selenium toner keep in a half-full plastic bottle? I was given some and figured using it was better than trying to dispose of it all at once.