The impacts of permanent irradiation on the terrestrial ecosystems of the Eastern-Ural Radioactive Trace

The complex radioecological investigations of the East-Ural Radioactive Trace were conducted. Three transects were established in EURT area: central, eastern and western. The current levels of soil contamination near the epicenter of the accident reach 30 × 103 kBq/m2 for 90Sr and 1 × 103 kBq/m2 for 137Cs. Contamination levels are reduced in accordance with a power function with increasing distance from the accident site and at a distance of more than 100 km become close to background values. In the EURT impact area vegetation is a complex of synanthropic and semi-natural plant communities in various stages of degradation and restoration successions. The current state of phytocenosises on the sites of the demolished local villages is largely determined by the degree of human impact in the pre-accident period, and remediation activities. For most species the viability of their seed progeny, formed in a gradient of radioactive contamination, are either not different from background samples or reduced half a century after the accident. Mutability of seed progeny in impact coenopopulations in all studied species was high. Radioadaptation phenomenon, i.e. increased resistance to provocative irradiation is rare and unstable