Vertical distribution of anthropogenic radionuclides in cores from contaminated floodplains of the Yenisey River

The Mining and Chemical Industrial Combine, Zheleznogorsk (MCIC, previously known as Krasnoyarsk-26) on the River Yenisey has contaminated the surrounding environment with anthropogenic radionuclides as a result of discharges of radioactive wastes. The purpose of this study was to investigate the vertical distribution of anthropogenic contamination (¹³⁷Cs and plutonium) within floodplain areas at different distances from the discharge point. Sites were chosen that display different characteristics with respect to periodic inundation with river water. Cs-137 activity concentrations were in the range 23–3770 Bq/kg (dry weight, d.w.); Pu-239,240 activity concentrations were in the range <0.01–14.2 Bq/kg (d.w.). Numerous sample cores exhibited sub-surface maxima which may be related to the historical discharges from the MCIC. Possible evidence indicating the deposition of earlier discharges at MCIC in deeper core layers was observed in the ²³⁸Pu:^239,240Pu activity ratio data: a Pu signal discernible from global fallout could be observed in numerous samples. Cs-137 and Pu-239,240 activity concentrations were correlated with the silt fraction (% by mass <63 μm) though no significant correlation was observed between (grain-size) normalised ¹³⁷Cs activity concentrations and distance downstream from the MCIC.     

Spatial distribution of heavy metals in soils of the flood plain of the Seversky Donets River (Russia) based on geostatistical methods

Environmental Geochemistry and Health - Soil contamination by heavy metals (HM) is a worldwide problem for human health. To reduce risk to human health from exposure to toxic chemicals associated...     

Cs contamination of the Techa river flood plain near the village of Muslumovo

The results of a radiometric survey of the Techa river flood plain near the village of Muslumovo in the Chelyabinsk region of Russia are presented. The observed territory extended 16.6 km along the riverbed, with a total area of 2.5 km². The collimated scintillation detector technique was applied to in situ field measurements of ¹³⁷Cs deposition on the soil. Maps of ¹³⁷Cs deposition and soil penetration depth were developed on the basis of approximately 5000 measurements. The total ¹³⁷Cs deposition within the surveyed territory has been estimated at 6.6 TBq. The means of the total ¹³⁷Cs soil depositions at half-kilometer sites on the flood plain and its distribution along the river have also been calculated. A maximum ¹³⁷Cs contamination above 7.5 MBq/m² is associated with a bank height up to 1 m above the usual water level. The data identify zones of intensive radionuclide sedimentation and transit zones.     

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 (137)Cs 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 (60)Co, (152)Eu and (154)Eu activity concentrations (30-40 kBq m(-2)) occur in low-lying areas inundated during flooding. Maximum (137)Cs and total (60)Co, (152)Eu and (154)Eu contamination densities on Cheriomukhov Island (250 km from the KMCC) were 390 and 50 kBq m(-2), respectively. Estimated (137)Cs inventories were 145, 148 and 16GBq for Beriozovy, Mikhin and Cheriomukhov Islands, respectively.