  We consider possible tests of the Einstein Equivalence Principle for physical
systems in which quantum-mechanical vacuum energies cannot be neglected.
Specific tests include a search for the manifestation of non-metric effects in
Lamb-shift transitions of Hydrogenic atoms and in anomalous magnetic moments of
massive leptons. We discuss how current experiments already set bounds on the
violation of the equivalence principle in this sector and how new
(high-precision) measurements of these quantities could provide further
information to this end.
