  We investigate the influence of modified nuclear parton distribution
functions (PDFs) on high-pT hadron production at RHIC and LHC energies using a
pQCD-improved parton model. For application at RHIC, we focus on the possible
contribution of the EMC modification of the nuclear PDFs in the x > 0.3 region
to the observed suppression of pi0 production at pT > 10 GeV/c in dAu
collisions. We study three different parameterizations of the nuclear PDF
modifications and find that they give consistent results for R_dAu(pT) for
neutral pions in the region 10 GeV/c < pT < 20 GeV/c. We find that the EMC
suppression of the parton distributions in the Au nucleus does not strongly
influence the R_dAu for pi0 in the pT region where the suppression is observed.
Using the HKN parameterization, we evaluate systematic errors in the
theoretical R_dAu(pT) resulting from uncertainties in the nuclear PDFs. The
measured nuclear modification factor is inconsistent with the pQCD model result
for pT > 10 GeV/c even when the systematic uncertainties in the nuclear PDFs
are accounted for. The inclusion of a small final-state energy loss can reduce
the discrepancy with the data, but we cannot perfectly reproduce the pT
dependence of the measured R_dAu(pT). For the LHC, we find that shadowing of
the nuclear PDFs produces a large suppression in the yield of hadrons with pT <
100 GeV/c in p(d)A collisions.
