The study is concerned with the corrosion of ultrapotashuranium glasses from the Rejstejn - Klastersky Mlyn locality in SumavaMountains, Czech Republic. The glass samples were taken from the dump of aformer glassworks. They stemmed from the year 1925 ± 5 years (the dating wasdone historically). The section also comprises soil, coal slag and alluvialsediments from the Otava river. Planar beta activity was measured in thesection: the lowest one of 0.34 kBq/m2 in soil and the highest of3.25 kBq/m2 in the horizon of the U-glasses. Four types of U-glasseswere distinguished: yellow, green alabaster, green and green-blue. They contain0.088 to 0.33 wt.% U and 8 to 14 wt.% K. The pH (aqueous extract) varies from5.11 in coal slag to 7.70 in the glass layers. The total content of U in the< 2 mm grain size fraction in the section was in the range from 4.8 ppm inthe alluvial deposit up to 56.5 ppm in the glass layer. The content of Uleachable by 1M CH3COONa ranges from 7 ppb in soil to 65 ppb in theglass horizon. Uranium migrates into the alluvium in the underlying bed of thedump (content of up to 58.9 ppb of leachable U). Under the given conditions inalluvium one can suppose the immobilisation of U, whereas As and Pb aretransported further. The green alabaster U-glass at the surface and along crackshas become corroded to a depth of 10 to 400 mm. Contraction fissures in thecorroded layer are coated with precipitated calcite. The corrosion involvesleaching of alkalies (up to 14 wt.% of glass) from the glass, redistribution ofuranium and sorption of lead on the surface. IR spectroscopy prove the hydrationof the glass, which is the result of K+ «H3O+ exchange.
