Just to get a little technical, Prime takes what is in your tap water, as long as its not too much, in other words, they have a set standard amount and they follow basically a tap water chart and what the DEP, DEC, Heath dept, local water company's etc use. Now that's not saying that it is magic in a bottle. If tap levels are higher then normal range then Prime will not be able to "precipitate the concentration" therefor leaving trace amounts of metals etc in the tank.
Assuming your levels are all within the "allowed" range then yes Prime will neutralize some metals and as they(Seachem)states it will precipitate the concentration making it less toxic.
This is from the from there tech support team. Just passing along some info I have gathered over the years of using Prime.
"When creating an aqua scape, strive for the beauty of imperfection, as its art and there is no wrong or right, it's left open for interpretation" James Findley