  Results of a careful analysis of the highly ionized absorption systems,
observed over the redshift range 2.198--2.2215 in the zem=2.24 HDFS-QSO
J2233-606, are presented. Strong OVI and NeVIII absorptions are detected. Most
of the lines show signature of partial coverage which varies from species to
species. This can be understood if the clouds cover the continuum emission
region completely and only a fraction of the broad emission line region. Using
photo-ionization models we analyze in more detail the component at zabs =
2.198. Absolute abundances are close to solar but the [N/C] abundance ratio is
larger than solar. This result, which is consistent with the analysis of high-z
QSO broad emission-lines, confirms the physical association of the absorbing
gas with the AGN. The observed column densities of NIV, NV and NeVIII favor a
two-zone model for the absorbing region where NeVIII is predominantly produced
in the highly ionized zone. It is most likely that in QSO J2233-606, the region
producing the NeVIII absorption can not be a warm absorber. One of the Lyalpha
absorption lines at zabs = 2.2215 has a flat bottom typical of saturated lines
and non-zero residual intensity in the core, consistent with partial coverage.
There is no metal-line from this Lyalpha cloud detectable in the spectrum which
suggests either large chemical inhomogeneities in the gas or that the gas is
very highly ionized. If the latter is true the cloud could have a total
hydrogen column density consistent with that of X-ray absorbers. It is
therefore of first importance to check whether or not there is an X-ray
warm-absorber in front of this QSO.
