  We present some early results from a study of five hot DA white dwarf stars,
based on spectra obtained using STIS. All show multiple components in one or
more of the strong resonance absorption lines typically associated with the
stellar photosphere (e.g. C IV, Si IV, N V and O V). Possible relationships
between the non-photospheric velocity components and the interstellar medium or
local stellar environment, are investigated, including contributions from
gravitational redshifting.
