IMPLICATIONS OF A PRIMORDIAL ORIGIN FOR THE DISPERSION IN D H IN QUASAR ABSORPTION SYSTEMS/

We explore the difficulties with a primordial origin of variations of D/H in quasar absorption systems. In particular we examine options suc h as a very large-scale inhomogeneity in the baryon content of the uni verse. We show that very large-scale (much larger than 1 Mpc) isocurva ture perturbations are excluded by current cosmic microwave background observations, Smaller-scale ad hoc perturbations (similar to 1 Mpc) s till may lead to a large dispersion in primordial abundances but are s ubject to other constraints.