Calcium is far too high indicating biounavailability. (adrenals)
Mercury is too low indicating detoxification problem.
Your question " toxicity or biounavailability ?" is nonsense because biounavailable copper is always toxic to the body. Unbound copper is a free radical damaging tissues 7/24 !
Remeber that copper itself is not the cause of copper toxicity. Damaged adrenals and the fail of the body to bind the copper is one cause of accumulation of toxic copper. The other cause are heavy metals which acts as superoxidizers oxidizing the copper and making it unavailable to the body. The adrenals then try 7/24 to bind this copperoxid and ultimatively fail into adrenal burn out. So there is a higher cause for all this mess. The indication that your body doesn't excrete mercury (as I said above level too low) is at least in my opinion a sign that mercury could well be a problem in your case.
Removing copper will give you only some time to restart the copper problem if mercury/lead is an unresolved problem in you. It is very unlikely that only one toxic metal shows up. Most of the people having copper problems have indeed a multiple metal problem.