Student or Learner
The following is from the dictionary:
[C or U] when you feel worried or nervous about something, or something that makes you feel worried
Concern for the safety of the two missing teenagers is growing.
There's a lot of public concern about/over dangerous toxins recently found in food.
Does it mean when concern means "worry for", "about", "over" and "for" are interchangeable?
I don't think there's much difference- I would probably use concerned for with a specific worry rather than for a general pattern- like the example of the missing teenagers, but you could replace it with the about/over.