  Long Gamma-ray Bursts (GRBs) signal the death of massive stars. The afterglow
emission can be used to probe the progenitor ambient through a detailed study
of the absorption pattern imprinted by the circumburst material as well as the
host galaxy interstellar medium on the continuum spectrum. This has been done
at optical wavelengths with impressive results. Similar studies can in
principle be carried out in the X-ray band, allowing us to shed light on the
material metallicity, composition and distance of the absorber. We start
exploiting this route through high resolution spectroscopy XMM-Newton
observations of GRB 090618. We find a high metallicity absorbing medium (Z> 0.2
Zsun) with possible enhancements of S and Ne with respect to the other elements
(improving the fit at a level of >3.4 sigma). Including the metallicity effects
on the X-ray column density determination, the X-ray and optical evaluations of
the absorption are in agreement for a Small Magellanic Cloud extinction curve.
