Composition of the Interstellar Medium

We present an analysis of the FeII, GeII, MgI, MgII, SI, SII, SiII and ZnII interstellar lines for 63 stars. Column density of MgII, SII, SiII and ZnII is well correlated with distance. However, the column density - distance relation should be used with care for the estimation of the distance to OB stars. For stars with large f(H2) this relation can lead to a large overestimation of the distance. The column densities of MgII, SiII and GeII (our largest samples of data) normalized to their total hydrogen column densities decrease with interstellar reddening E(B-V) as expected for elements that are incorporated into dust grains. The GeII abundance (GeII/H) is lower in dense molecular clouds. The abundances of all analyzed elements are generally lower than their Solar System values.