  We present an analysis of the X-ray absorption properties of 6 gamma-ray
burst (GRB) afterglows measured with BeppoSAX. Between 8 hrs and 20 hrs after
the initial GRB trigger, individual spectra can be described by a power-law
with a photon index of ~2 and absorption marginally consistent with the
galactic value. Taken collectively, the data are inconsistent with zero
absorption at the >99.999 confidence level. The data are only marginally
consistent with a distribution of column densities varying as the total
galactic absorption in the direction of each of the bursts (chi^2 =9.6 for 6
degrees of freedom). The data are consistent with cosmological models in which
GRB occur within host galaxies. By simultaneously fitting a power-law spectral
model with absorption fixed at the galactic value and additional, redshifted,
absorption to all 6 afterglow spectra, the best-fit average absorption within
the host objects is found to be (1.01 ^0.28_0.51) 10^22 atom cm^-2. This value
is compatible with the host galaxy column densities inferred from optical data
for GRB970508, GRB971214 and GRB980329, supporting the hypothesis that GRB
occur within heavily absorbed star forming regions of their host galaxies.
