What can cause copper pipe to corrode?
Based on your picture:


Copper pipe in concrete; a problem.
Copper pipe connected to galvanized iron pipe (evidently) without a dielectric union; a problem.
Electrical ground connected to the galvanized iron pipe, not the copper pipe; likely also a problem, and would be a problem for the grounding if there was a dielectric union.


It is just possible that the union there is dielectric, in which case the copper above it and the ground wire above it are the main issues, but it's unlikely. A dielectric union is correctly used where the pipe material changes from copper to iron.

You could certainly start with a dielectric union and moving the ground wire (or having it moved by an electrician that knows what he or she is doing, unlike the one that put it there.)