There are too many unknown factors to reasonably answer that. Depending on what types, how wide, how high, what do you mean by proper anchor, what's a white iron shelf, do you mean a rod when you say hanging unit... More specific information would help get the answer you are looking for.
Sorry I don't have an answer.
Is this a trick question?
If not properly anchored minimal weight.
Thanks! Your answer is awaiting moderation.