**2.3. Suspended matter of the Yenisei River: trucks for transport of radionuclides in the water flow**

Because major part of radionuclides has been found in the suspended matter, transporting by water stream of Yenisei, more thorough studies of suspended matter of Yenisei have been conducted.

The Behaviour of Natural and Artificial Radionuclides in a River System: The Yenisei River, Russia as a Case Study http://dx.doi.org/10.5772/65743 367


discharge area. Content of TUE in surface basins is extremely low and equals 10−10–10−15 M, within limits of the most sensitive spectral techniques, e.g. mass-spectrometry [23, 24]. For the precise determination of TUE contents as well others radionuclides such as 90Sr in water systems, the most frequently used methods are hybrid ones, combining preliminary concentrating and separating of radioisotopes with various detecting methods, e.g. alpha-, beta- and

To increase the number of identified radionuclides, the method for concentrating the radionuclide from Yenisei water samples has been introduced [8]. Data obtained after concentration

**Figure 3.** Average tritium content in water samples of Yenisei (distance down the stream from places of water discharge

Water samples contain the bunch of artificial radionuclides. To increase the number of identified radionuclides, the method for concentrating the radionuclide from Yenisei water samples

The method for concentrating the radionuclide was accepted on the basis of two widely known methods of co-precipitation with oxyhydroxide of Fe (III) and Mn (IV) oxide [28, 29]. Artificial radionuclides, which have different origin, have been found in water samples: induced (activated) radionuclides—24Na, 46Sc, 51Cr, 54Mn, 59Fe, 60Co, 65Zn, 76As and others; satellite radionuclides—99Mo, 124Sb, 131I, 133I, 141Ce, 144Ce and others. The most distinctive are trans-uranic radionuclides—239Np, isotopes of Pu. In water samples, taken down the stream from MCC (5 km), besides the decreasing concentration of artificial radionuclides there were found some natural radionuclides: 210Pb and 232Th. There were included the presence of longliving satellite isotope 152Eu (T1/2 = 13.6 years) ~ 0.04–0.06 Bk/l and the presence of short-living

activated radionuclide 58Co (T1/2 = 71.3 days) ~ 0.03–0.07 Bk/l in water samples.

**2.3. Suspended matter of the Yenisei River: trucks for transport of radionuclides in** 

Because major part of radionuclides has been found in the suspended matter, transporting by water stream of Yenisei, more thorough studies of suspended matter of Yenisei have been

gamma-spectrometry [25–27].

of water samples is given in **Tables 1** and **2**.

has been improved [8].

by MCC).

366 Water Quality

**the water flow**

conducted.

**Table 1.** Radionuclide content in water samples after concentrating, taken in the place of MCC discharge ("0 km"), Bk/l.


**Table 2.** Radionuclide content in water samples, taken from Atamanovo region, after concentrating (taken at 5 km down the stream from the place of discharge), Bk/l.

The investigations were carried out in the middle reach of the River Yenisei at the site 15 km (from the inflow of the Plosky stream (0 km) to the village Bolshoy Balchug (15 km) (**Figure 1**). The stream with technogenic admixtures propagates along the bank of the river not more than 0.1 one-tenth of the width of the river, i.e. along the flood plain where the river flow speed and the width are several times less.

As a result of ultra-filtration method, it was found that the main part of the suspended particles (up to 90%) was concentrated in the pelitic fraction of >5 µm. The filters with the suspensions were fixed on the specimen mount with the help of the conducting double-sided adhesive carbon type and placed into the electron microscope chamber. The precipitate was found to contain particles of quartz, mica and iron-containing minerals (limonitic and magnetic iron), mainly, with the size not exceeding 10–15 µm. Moreover, the precipitate revealed the presence of a considerable amount of various biological objects (diatoms, annelids, plant spores, etc.). All the mineral particles and biota were covered with a layer of fine limoniticclayish particles. Spectral analysis of some parts of the sample (selected particles, characteristic details) was carried out. The suspended matter contains a large colony of diatoms, for example, *Meridion circulare, some cyclotellas* and *opyphoros, Cyclotella vor. Jacutca* (**Figure 4**).

The fraction with the size of '5-1 µm' uniformly covers the filter surface with a layer of fine particles. The precipitate mainly consists of mineral components (calcite, clays, clayish minerals, quartz and gypsum debris).

The fraction '1.0–0.2 µm' uniformly covers the filter surface with a layer of fine particles of the micron and submicron size, they are mainly aluminosilicate compounds having various structure and composition, limonite, calcite and gypsum.

**Figure 4.** Material composition of the water suspensions (separated by the ultra-filtration method). The fraction ≥5 µm. Magnification power of 2000×.

The material composition of the solid suspensions in the Yenisei River water generally corresponds to the mineral compositions of the rocks and the products of their hypergenesis which collected from the channel and the banks of the river. Occasionally, the admixture of the particles of technogenic origin (ash wastes from boiler stations) is observed.

The investigations were carried out in the middle reach of the River Yenisei at the site 15 km (from the inflow of the Plosky stream (0 km) to the village Bolshoy Balchug (15 km) (**Figure 1**). The stream with technogenic admixtures propagates along the bank of the river not more than 0.1 one-tenth of the width of the river, i.e. along the flood plain where the river flow

As a result of ultra-filtration method, it was found that the main part of the suspended particles (up to 90%) was concentrated in the pelitic fraction of >5 µm. The filters with the suspensions were fixed on the specimen mount with the help of the conducting double-sided adhesive carbon type and placed into the electron microscope chamber. The precipitate was found to contain particles of quartz, mica and iron-containing minerals (limonitic and magnetic iron), mainly, with the size not exceeding 10–15 µm. Moreover, the precipitate revealed the presence of a considerable amount of various biological objects (diatoms, annelids, plant spores, etc.). All the mineral particles and biota were covered with a layer of fine limoniticclayish particles. Spectral analysis of some parts of the sample (selected particles, characteristic details) was carried out. The suspended matter contains a large colony of diatoms, for example, *Meridion circulare, some cyclotellas* and *opyphoros, Cyclotella vor. Jacutca* (**Figure 4**).

The fraction with the size of '5-1 µm' uniformly covers the filter surface with a layer of fine particles. The precipitate mainly consists of mineral components (calcite, clays, clayish miner-

The fraction '1.0–0.2 µm' uniformly covers the filter surface with a layer of fine particles of the micron and submicron size, they are mainly aluminosilicate compounds having various

**Figure 4.** Material composition of the water suspensions (separated by the ultra-filtration method). The fraction ≥5 µm.

speed and the width are several times less.

368 Water Quality

als, quartz and gypsum debris).

Magnification power of 2000×.

structure and composition, limonite, calcite and gypsum.

Thus, it was shown that the suspended substance is similar to its geomorphology with the bottom sediments of the Yenisei River. However, the suspensions entering the river with the industrial discharge water significantly differ from the suspensions of the mainstream both in their composition and particle size.

At the sampling of the district runoff of radionuclides when the time of the discharge contact with the river water was insignificant, the radionuclides <sup>3</sup> H, 24Na, 60Co, 239Np and 99Mo (~90%) were mainly presented as a fraction <0.2 µm (filtrate). These can be both free ions in the molecular solution (e.g., 24Na+ ), and molecules or sorbed ions in colloid particles which managed to pass through a 0.2 µm filter. 46Sc, 214Bi, 103Ru are mainly presented in solid phase, while the last two isotopes being in the coarsest fraction (more than 90% of them). 85Sr and 131I have less uniform phase distribution. 76As is almost absent in the most coarse fraction (>5 µm). In the samples taken 5 km downstream, there is a decrease of the total activity, first of all, due to the coarse particle sedimentation. The radionuclide redistribution according to the size fractions was found: almost the whole amount of 60Co is concentrated in the fraction with the size of >1 µm, a considerable amount of 214Bi is transformed into a solution (the fraction <0.2 µm), almost 40% of 99Mo and up to 70% of 24Na are transformed into the fraction of 1–0.2 µm. With the total background level decrease there appear natural radionuclides 212Pb and 234Th in the solid phase as well as 65Zn in the solution.
