  The validity of the hypothesis that the massive black holes in high redshift
quasars grew from stellar-sized "seeds" is contingent on a seed's ability to
double its mass every few ten million years. This requires that the seed
accrete at approximately the Eddington-limited rate. In the specific case of
radiatively efficient quasiradial accretion in a metal-poor protogalactic
medium, for which the Bondi accretion rate is often prescribed in cosmological
simulations of massive black hole formation, we examine the effects of the
radiation emitted near the black hole's event horizon on the structure of the
surrounding gas flow. We find that the radiation pressure from photoionization
significantly reduces the steady-state accretion rate and renders the
quasiradial accretion flow unsteady and inefficient. The time-averaged
accretion rates are a small fraction of the Eddington-limited accretion rate
for Thomson scattering. The pressure of Ly-alpha photons trapped near the HII
region surrounding the black hole may further attenuate the inflow. These
results suggest that an alternative to quasiradial, radiatively efficient
Bondi-like accretion should be sought to explain the rapid growth of
quasar-progenitor seed black holes.
