  We present the column densities of heavy-elements and dust depletion studies
in twostrong Mg~II absorption systems at $z\sim1.4$ displaying the 2175-{\AA}
dust extinction feature. Column densities are measured from low-ionization
absorption lines using Apparent Optical Depth Method on the Keck/ESI spectra.
We find the dust depletion patterns resemble to that of cold diffuse clouds in
the Milky Way (MW). The values, [Fe/Zn]$\approx -1.5$ and [Si/Zn]$<-0.67$, are
among the highest dust depletion measured for quasar absorption line systems.
In another 2175-{\AA} absorber at $z$=1.64 toward the quasar SDSS
J160457.50+220300.5, Noterdaeme et al. (2009) reported a similar dust depletion
measurement ([Fe/Zn]=$-1.47$ and [Si/Zn]=$-1.07$) and detected C~I and CO
absorption lineson its VLT/UVES spectrum. We conclude that heavy dust depletion
(i.e. a characteristic of cold dense clouds in MW) is required to produce a
pronounced 2175-{\AA} extinction bump.
