Patterns and inventories of radioactive contamination of island sites of the Yenisey River, Russia

The distribution of radioactive contamination at three island sites downstream from the Krasnoyarsk Mining and Chemical Combine (KMCC) was studied with the objectives of mapping contamination levels, interpreting radionuclide distributions through consideration of alluvial processes and determining radionuclide inventories. Contamination was measured using in situ gamma spectrometry and landforms characterised using topographic surveying methods. Maximum 137Cs contamination densities (700 kBq m−2) were found on low- and middle-level floodplains and low-lying interconnecting areas of Beriozovy Island (16 km from the KMCC). On Mikhin Island (180 km from the KMCC) maximum total 60Co, 152Eu and 154Eu activity concentrations (30–40 kBq m−2) occur in low-lying areas inundated during flooding. Maximum 137Cs and total 60Co, 152Eu and 154Eu contamination densities on Cheriomukhov Island (250 km from the KMCC) were 390 and 50 kBq m−2, respectively. Estimated 137Cs inventories were 145, 148 and 16 GBq for Beriozovy, Mikhin and Cheriomukhov Islands, respectively.