Visual extinction against UV metal abundances in solar units. The metallicities obtained from the literature based on Zn element are marked with red stars. The rest of the data points are based on Si element metallicities (see Table 6). GRB 080607 is indicated with a red square. The metallicity or A_V upper limits are represented by small circles or stars. The dashed line indicates metals-to-dust relation for the Local Group (indicated as LG).