  We present an analysis of high-dispersion and high signal-to-noise ratio
spectra of the DAZ white dwarf GALEX J1931+0117. The spectra obtained with the
VLT-Kueyen/UV-Visual Echelle Spectrograph show several well-resolved Si II
spectral lines enabling a study of pressure effects on line profiles. We
observed large Stark shifts in silicon lines in agreement with laboratory
measurements. A model atmosphere analysis shows that the magnesium, silicon and
iron abundances exceed solar abundances, while the oxygen and calcium
abundances are below solar. Also, we compared the observed line profiles to
synthetic spectra computed with variable accretion rates and vertical abundance
distributions assuming diffusion steady-state. The inferred accretion rates
vary from dM/dt=2x10^6 for calcium to 2x10^9 g/s for oxygen and indicate that
the accretion flow is dominated by oxygen, silicon and iron while being
deficient in carbon, magnesium and calcium. The lack of radial velocity
variations between two measurement epochs suggests that GALEX J1931+0117 is
probably not in a close binary and that the source of the accreted material
resides in a debris disc.
