Heavy Elements in QSOs: Star Formation and Galaxy Evolution at High   Redshifts
  Intrinsic emission and absorption lines of QSOs provide several independent probes of the metal abundances in QSO environments. They indicate that the metallicities are typically solar or higher out to redshifts z > 4. These results support models of galaxy evolution where galactic nuclei, or dense condensations that later become galactic nuclei, form stars and evolve quickly at redshifts higher than the QSOs themselves. 
Fred Hamann (UCSD)