Radioecological studies of bottom sediments of the Zolotitsa river and in the area of development of the diamond deposit M.V. Lomonosov (Arkhangelsk region)

Radioecological studies of bottom sediments of the Zolotitsa river and in the area of development of the diamond deposit M. V. Lomonosov (Arkhangelsk region)

Bazhenov A. V., Yakovlev E. Yu., Druzhinin S. V., Iglovsky S. A.

N. LaverovFederal Centre for Integrated Arctic Research of the Ural Branch of Russian Academy of Sciences, 109 Severnoj Dviny Emb., Arkhangelsk, 163000, Russia. e-mail: abv-2009@yandex. ru

Abstract.

Small rivers and their tributaries are the most important element of natural and economic systems. The special role that small rivers play lies in the fact that, being in the upper and peripheral parts of large river basins, they largely determine the general ecological situation in them. Bottom sediments are a complex multicomponent system and are characterized by a variety of forms. They play an extremely important role in the formation of the hydro-chemical regime of water masses and the functioning of the ecosystem of water bodies and watercourses as a whole. They can act as an indicator for identifying the composition, intensity, and scale of technogenic pollution, because their composition reflects the biogeochemical characteristics of the catchment areas. In 1980, a diamond deposit named after M. V. Lomonosov was open. Open pit mining has a whole range of negative impacts on the unique natural environment. To accomplish radioecological research, 50 samples of bottom sediment were taken in the upper reaches of the river, Zolotitsa, in the area of development of the diamond deposit named after M. V. Lomonosov (Arkhangelsk region). It was found that the complete purification of pumped out pit water, as a result of filtration through the bog massif, does not occur. In this case, the discharge of bog (actually drainage) waters enriched in ²²⁶Ra and ²³²Th into the channel of the Zolotitsa river occurs over a fairly wide area with a length of about 3 km. This can be seen from the results of studies of radionuclides in bottom sediments. This conclusion is supported by the fact that the nature of the increase in the activity of ¹³⁷Cs in bottom sediments in this area repeats the pattern of changes in ²³²Th and ²²⁶Ra. The technogenic isotope, ¹³⁷Cs, formed in the course of nuclear tests in the atmosphere and accidents at nuclear power plants cannot be found in the drainage water, therefore its presence in bottom sediments is explained solely by washout from the earth's surface. During the discharge of drainage water into the bog, ¹³⁷Cs, which is fixed in the upper layer of peat as a result of global fallout, is activated and migrates from a large area of bog massif and is unloaded into the channel of the Zolotitsa river together with ²²⁶Ra and²³²Th.

Keywords: Bottom sediments, natural and man-made radioactivity, diamond deposit, mining and processing plant, Zolotitsa River, Arkhangelsk region

⇐ Предыдущая 123 4 5 6 Следующая ⇒