The growth of barrier-type anodic films at 50 A m(-2) in 0.1 M tungstate/ethylene glycol electrolyte at 293 K has been studied using Rutherford backscattering spectroscopy and transmission electron microscopy. The resultant films are composed mainly of alumina and form at a Faradaic efficiency approaching 100%. The films are contaminated in discrete regions by incorporated species consisting of either directly-incorporated or derivatives of tungstate anions and solvent molecules. The tungsten species incorporated into the film are immobile during film growth, contrasting with the behaviour of tungsten species incorporated from aqueous electrolytes, which migrate outwards. The modified behaviour is attributed to incorporation of tungsten and solvent species into interstices in the alumina structure. Additionally, a mobile solvent species is present in the film which migrates inwards at about 60% of the migration rate of O2-/OH- ions.