We present sequential optical spectra of the afterglow of GRB 010222 obtained one day apart using the Low Resolution Imaging Spectrometer ( LRIS ) and the Echellette Spectrograph and Imager ( ESI ) on the Keck telescopes .
Three low-ionization absorption systems are spectroscopically identified at z _ { 1 } = 1.47688 , z _ { 2 } = 1.15628 , and z _ { 3 } = 0.92747 .
The higher resolution ESI spectrum reveals two distinct components in the highest redshift system at z _ { 1 a } = 1.47590 and z _ { 1 b } = 1.47688 .
We interpret the z _ { 1 b } = 1.47688 system as an absorption feature of the disk of the host galaxy of GRB 010222 .
The best fitted power-law optical continuum and [ Zn/Cr ] ratio imply low dust content or a local gray dust component near the burst site .
In addition , we do not detect strong signatures of vibrationally excited states of H _ { 2 } .
If the GRB took place in a superbubble or young stellar cluster , there are no outstanding signatures of an ionized absorber , either .
Analysis of the spectral time dependence at low resolution shows no significant evidence for absorption-line variability .
This lack of variability is confronted with time-dependent photoionization simulations designed to apply the observed flux from GRB 010222 to a variety of assumed atomic gas densities and cloud radii .
The absence of time dependence in the absorption lines implies that high-density environments are disfavored .
In particular , if the GRB environment was dust free , its density was unlikely to exceed n _ { H } = 10 ^ { 2 } cm ^ { -3 } .
If depletion of metals onto dust is similar to Galactic values or less than solar abundances are present , then n _ { H } \geq 2 \times 10 ^ { 4 } cm ^ { -3 } is probably ruled out in the immediate vicinity of the burst .