If civilization survives they will have the equipment to detect a nuclear hazard and they will preserve the meaning for long enough for it not to be a big deal. If civilization does not survive an old waste facility is a very minor issue in comparison.
Likewise, biohazards will simply not be a threat for long enough for the meaning to be lost unless things fall apart at which point again it's a very minor issue in comparison.
If civilization survives they will have the equipment to detect a nuclear hazard and they will preserve the meaning for long enough for it not to be a big deal. If civilization does not survive an old waste facility is a very minor issue in comparison.
Likewise, biohazards will simply not be a threat for long enough for the meaning to be lost unless things fall apart at which point again it's a very minor issue in comparison.