Left: NLTE values of [O/Fe] for our RR Lyr stars compared to the giants from Cayrel et al. (2004). Right: [Mg/Fe], corrected for NLTE, compared to EMP giants (Cayrel et al. 2004), dwarfs (Bonifacio et al. 2009), as well as the RHB stars from (Preston et al. 2006), all have been corrected for NLTE effects by applying corrections from Andrievsky et al. (2010). Results for CS 22881-039 are shown as a red square (this paper) and asterisk (Preston et al. 2006); other symbols as in Fig. 2.