RESUMEN
A brief overview of the radioactive waste inventory of the 'Mayak' PA reprocessing plant, Chelyabinsk Region, Russia is given together with a description of the environmental contamination caused by its activities and the origins of contamination. The joint Russian-Norwegian field work in 1994 is described, together with the major analytical results. The field work was of a limited extent, and was not designed to include a complete mapping of the environmental contamination around the plant. The results are, however, in good agreement with the very extensive previous Russian investigations. The highest concentrations of radioactivity were found in Reservoirs 10 and 11 and at the floodplain of the upper Techa River (Asanov Swamp). Also high concentrations are found in biota, especially fish from Reservoir 10.