Global radioactive deposition on the Yenisey-river catchment and its contribution to the summary contamination of the valley

¹ Russian Academy of Sciences, Institute of Global Climate and Ecology, Glebovskaya Str. 20-b, 107258 Moscow, Russia
² Moscow State University, Department of Geography, Laboratory of Soil Erosion and Fluvial Processes, Vorobiovy Gory, 119899 Moscow, Russia

Abstract

The results of the retrospective global radioactive contamination mapping of the Enisey-river catchment are presented. The maps of spatial , ¹³⁷Cs distributions of 1964, 1974, 1986, 2000 are compiled using the geo-information technologies in the Institute of Global Climate and Ecology. The territory of mapping is 2600000 km². The mapping is done from the airborne-gamma-spectrum data obtained at the beginning of 1960, of 1970 and 1990. In 2000 the global levels of ¹³⁷Cs are 0.4-3 kBq/m². A small contribution of Chernobyl deposition can be registered on the maps built later 1986 (0.02-0.15 kBq/m²). The levels of 2.5-3 kBq/m² in the region of Severo-Eniseyski and Teya localities can be estimated as the tail part of the eastern Chernobyl pattern. The present levels of 2.59-122 kBq/m² are observed on the Enissey valley at distances of 0-1700 km from Krasnoyarsk-26. The parameters of runoff and soil erosion are estimated using the cartographic information, provided by the Laboratory of River Processes and Soil Erosion of the Moscow State University. A part of ¹³⁷Cs, accumulated in the Enisey-valley from early 1960 to 2000 with the transport of soil material from interfluve of all Enisey tributaries, will be estimated using a balance model of soil erosion. The contribution of ¹³⁷Cs from the catchment to the valley is estimated with respect to total ¹³⁷Cs deposited in the valley.