The behaviour of some technogenical long living radionuclides in the freshwater and terrestrial ecosystems of radioactive contaminated areas within Urals region has been investigated. There were examinated the Techa River contaminated by radionuclides for all over its stretch, the territory of the Eastern Urals Radioactive Trace and the 30-km zone of regularly operating Beloyarskaya NPP. It was revealed the peculiarities of 90Sr, 137Cs, 238-240Рu migration, accumulation and transformation in the components of the freshwater and terrestrial ecosystems. With using mathematical modelling the integral inventories of radionuclides for the main links of the investigated ecosystems were calculated.