  We present a study of the iron abundance pattern in hot hydrogen-rich (DA)
white dwarfs. The study is based on new and archival far ultraviolet
spectroscopy of a sample of white dwarfs in the temperature range 30,000 K <
T_eff < 64,000 K. The spectra obtained with the Far Ultraviolet Spectroscopic
Explorer along with spectra obtained with the Hubble Space Telescope Imaging
Spectrograph and the International Ultraviolet Explorer sample FeIII to FeVI
absorption lines enabling a detailed iron abundance analysis over a wider range
of effective temperatures than previously afforded. The measurements reveal
abundance variations in excess of two orders of magnitude between the highest
and the lowest temperatures probed, but also show considerable variations (over
one order of magnitude) between objects with similar temperatures and surface
gravities. Such variations in cooler objects may be imputed to accretion from
unseen companions or so-called circumstellar debris although the effect of
residual mass-loss and selective radiation pressure in the hottest objects in
the sample remain dominant.
