Technogenic pollution and its migration in the water flow of the Yenisei River
Bondareva, Lydia; Zeer, Galina; Gerasimov, Valery; Zhizhaev, Anatoly
The results of the monitoring of the radiation-chemical situation in the middle reach of the Yenisei River located in the nearest zone of the influence of the Mining and Chemical Combine of Rosatom have been described in the paper. The area of the study has been the water of the Yenisei River, the suspended matter of the main water flow and one of the right-bank tributary which is considered to be the main point of the discharge of the Mining and Chemical Combine. The methods of gamma-spectroscopy, mass spectrometry and scanning electron microscopy have been used in the work. The Yenisei River water contains 180-320 ng·L-1 of dissolved uranium. However, near the discharge points of the Mining and Chemical Combine the content of the dissolved uranium was 6-9 times higher. An artificial uranium isotope 236U (T1/2 = 2.39·10 7 years) has also been found. A certain ratio of the uranium isotope content (235U/238U, 234U/235U) has been different from the natural ratio. It has been shown that a wide range of radionuclides of different genesis flows into the waters of the Yenisei River. The radionuclides 24Na, 60Co, 239Np and also, 99Mo (∼90 %) are present as particles with the size of < 0.2 μm, the other isotopes under study present as coarse particles. It has been demonstrated that radionuclides are transported by the water flow in the form of a molecular solution or with the suspended matter. The mineral-chemical composition of the suspended matter of the river Yenisei corresponds to the composition of the bottom sediments and consists of finely dispersed mineral particles, plant and organic detritus and living biological objects. As a result of this work it has been shown that the artificial radionuclide inflow and the increased uranium content in the ecosystem of the Yenisei River have been due to the operation of the Mining and Chemical Combine.