  Recent observations suggest the existence of a white dwarf population in the
Galactic halo, while others suggest that deuterium has been astrated in systems
at high redshift and low metallicity. We propose that these observations could
be signatures of an early population of intermediate-mass stars. Such a
population requires a Population III initial mass function different from that
of the solar neighborhood, as perhaps also suggested by the observed cosmic
infrared background. Also, to avoid overproduction of C and N, it is required
that the Z=0 yields of these stars have low ($\sim 10^{-3}$ solar) abundances
as suggested by some recent calculations. Under these assumptions, we present a
model which reproduces the observed D vs Si trend, and predicts a high cosmic
Type Ia supernova rate, while producing a white dwarf population that accounts
for only $\sim$ 1.5% of the dark halo. This scenario can be tested by
observations of the cosmic supernova rate, and by confirmation and further
studies of the putative white dwarf halo population.
