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Technogenic Fallout of Uranium and Thorium in the Vicinity of Novosibirsk (Russia, West Siberia)
Available online at www.sciencedirect.com
ScienceDirect Physics Procedia 84 (2016) 280 – 287
International Conference "Synchrotron and Free electron laser Radiation: generation and application", SFR-2016, 4-8 July 2016, Novosibirsk, Russia
Technogenic fallout of Uranium and Thorium in the vicinity of Novosibirsk (Russia, West Siberia) Svetlana Yu. Artamonova* V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia
Abstract Evaluation of the contribution of definite pollution sources among many others is rather complicated scientific challenge, but its solution may become decisive for the realization of measures aimed at ecological remediation of the territories. Element composition of aerosol particles accumulated during winter in the snow cover of Novosibirsk was determined by means of X-ray fluorescence measurements with synchrotron radiation at the “Siberian Synchrotron and Terahertz Radiation Center” based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. Means of ICP-MS and scanning electron microscopy were used additionally. These studies allowed revealing the contribution of separate industrial enterprises into the general technogenic pollution of the megapolis with uranium and thorium. © Published by Elsevier B.V. B.V. This is an open access article under the CC BY-NC-ND license ©2016 2016The TheAuthors. Authors. Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility ofthe organizing committee of SFR-2016. Peer-review under responsibility of the organizing committee of SFR-2016.
Keywords: XFA-SR, geochemistry of technogenesis, emission from power plants, emission from nuclear fuel plants, technogenic aerosol, natural radionuclides, uranium isotopes, ecological risk
1. Introduction. Air pollution in industrial cities had become an urgent problem long ago. Investigation of uranium and thorium content in technogenic aerosol is especially urgent because of the risk for human health. Under the conditions of Siberia, snow cover is an ideal object to study geochemistry of technogenesis because of accumulation of aerosol particles and gaseous compounds in it.
* Corresponding author- Svetlana Yu. Artamonova. Tel.: +7-913-700-32-91 fax: +7-383-333-27-91. E-mail address: [email protected]
1875-3892 © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of SFR-2016. doi:10.1016/j.phpro.2016.11.048
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It is known that snow crystals in winter (and raindrops in summer) passing through the air capture solid aerosol particles and gaseous compounds. Also, there is fallout of heavy aerosol particles under gravity. The goal of the work was evaluation of the radioactive uranium-thorium content of technogenic aerosol pollution of Novosibirsk vicinity. Objects of investigation. There are 4 heat-electric generating plants (HEPP) in Novosibirsk (рис.1, a); two of them (HEPP-2 and HEPP-3) are situated at the left bank of the Ob. The nuclear fuel plant – Novosibirsk Chemical Concentrates Plant (NCCP) – produces fuel elements for atomic stations and has its own HEPP-4 similar in parameters with HEPP-3 (see Fig. 1, b). The fuel used at HEPP-2 is mainly black oil, while HEPP-3 and HEPP-4 use natural gas. Only the most powerful (by a factor of 2.5) plant HEPP-5 uses brown coal as fuel: the amount burnt every day is 10000 t by http://news.ngs.ru/photo/2372183/ (2016). Coal is known to be a natural sorbent; it can contain substantial amounts of U and Th, so emission from power plants can also contain these radionuclides. There is also a Tin Plant (NTP) in Novosibirsk; its emission pollutes urban air with As, Sn and a number of other chalcophilic elements by Artamonova et al. (2007, 2011)(see Fig.1, c).
Fig. 1. (a) Location of the industrial enterprises of Novosibirsk. Designations: sampling points: 1 – snow (number), 2 – soil; diffuse aureole of aerosol pollution: 3 – from NCCP, 4 – from HEPP-5, 5 – from NTP, 6 – trace pollution from NTP, 7 – wind rose; (b) The diagram shows the major parameters of HEPP facilities in Novosibirsk: thermal power, Gcal (1), electric power, MW (2), and chimney height, m (3); (c) Dynamics of a decrease in As content in the diffuse aureole of aerosol pollution with an increase in the distance in the north-eastern direction (according to the wind rose) (1), in other directions (2); the content of As in aerosol in the background site (3) (the line shows the trend of changes).
Experimental. The winds of southern and south-western direction dominate in the region under investigation in winter by The climate of Novosibirsk (1979), so the main directions of snow cover sampling were to the north-east of the plants at a distance up to 110 km from the city (Fig. 1, a). The background site was chosen at the windward side at a distance of 12 km in the southwestern direction from the city.
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To exclude the effect of motor roads, sampling was carried out at a distance not less than 200 m. Large-volume snow samples (70 to 200 l) were collected by making shafts through the whole depth of snow cover. Melted snow was filtered through the "blue band" paper filter. The dust content (suspension content, mg/l) was determined as a ratio of the mass of suspension to the volume of melted snow; average diurnal fallout technogenic load (mg/m2*day) was determined as a ratio of suspension mass to the area of sampling and the period of the formation of stable snow cover till sampling date. The concentrations of U, Th and other elements were determined by means of X-ray fluorescence measurements with synchrotron radiation (XFA-SR) at the Siberian Center of synchrotron and terahertz radiation of the Budker Institute of Nuclear Physics SB RAS by Levichev (2016). The lower detection limit is down to 0.1- 0.3 ppm depending on the energy of excitation of emission lines (Table 1). Relative error of XFA-SR is equal or less 15 %. External standard of soil SOIL-7 (International Atomic Energy Agency) was used (analyst: Yu.P. Kolmogorov) by Baryshev et al. (1991). Simple sample preparation allows the analysis of small weighted portions without losses of volatile and other mobile elements, which makes XFA-SR the method of priority to study technogenic aerosol.
V 5 Rb 0.15
Table 1. Lower detection limits of XFA-SR (ppm) A. 23 KeV of primary radiation Cr Mn Fe Ni Cu Zn Ga 4 Sr 0.15
4 Y 0.15
3 Zr 0.15
3 2 1 0.5 Nb Mo Pb Tl 0.15 0.1 0.3 0.2 B. 36.5 KeV of primary radiation Cs Ag Cd Sn Sb 0.2 0.3 0.3 0.2 0.2
Ge
As
Se
Br
0.5 Bi 0.2
0.4 U 0.3
0.3 Th 0.3
0.25
I 0.2
Isotope analysis of 235U, 238U with the relative error < 2 % was carried out using mass spectrometry with inductively coupled plasma (ICP-MS). The samples were preliminarily transferred into solutions by means of melting: 1) with KOH, 2) with LiBO2. Aerosol particles were studied with a scanning electron microscope LEO 1430 VP in the mode of back-scattered electrons. The diameter of scanning beam of the spectrometer was ~ 0.5 μm, which allowed us to determine the composition of aerosol particles up to 0.5-1 μm in size. At the magnification of 1500, not less than 5000 fields of vision 212 X 159 μm in size were examined; each of them contained not less than 300 microparticles. Results and discussion. The strongest snow pollution is observed within 0.5 – 1.5 km range from industrial enterprises, where the dust content of snow was about 60 – 100 mg/l. The aureoles of aerosol pollution from HEPP2, HEPP-3 and NTP at the left bank of the Ob extent at a distance of 1.5–3 km to the north-east and are limited by the Ob river. These enterprises are situated on the lower bank with altitude of 120-130 absolute meters, heights of their chimneys are 100 m. So surface winds along the river valley are likely to make a physical barrier for their emissions (Fig.1). XFA-SR studies showed that the average U content in technogenic aerosol from HEPP-2 and HEPP-3 is not high: 2.9 g/t, Th – 7.2 g/t (Fig.2). In aerosol from NTP, the average Th content is similar to that in the aureole from HEPP-2 and HEPP-3, while U content is slightly higher –3.5 g/t. The concentrations of Th and U in aerosol from HEPP-2, HEPP-3 and NTP are similar to those in aerosol outside the aureoles of major technogenic pollution in the southern and south-eastern vicinity of Novosibirsk, in which the average content of U is 3.0 g/t, Th – 7.6 g/t (Fig. 2). No significant correlation of U and Th content with the elements indicating the emission of NTP (As, Sn and other by Artamonova et al. (2007)) and with the elements indicating emission from HEPP-2, HEPP-3 (Mn, V, I, Ga by Artamonova (2011)) is observed. It is known that the natural Th/U ratio is within the range 2.5–5.0 by Rikhvanov (2009). In the aerosol of the background site, Th content is 8.3 g/t, U – 2.7 g/t, so Th/U is equal to 3.1, which is close to the clarke ratio of the Earth's crust (Fig. 3). The natural Th/U ratio in aerosol of the background site and the minimal dust content in snow (3.14 mg/l) of the background site provide evidence of the successful choice of the background site where the effect of technogenesis is minimal and aerosol is mainly of natural origin. In aerosol outside the major aureoles of technogenic pollution and within the limits of aureoles of HEPP-2 and HEPP-3 the average Th/U ratio is equal to
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2.9, which corresponds to the natural ratio. In the aerosol from NTP, Th/U is anomalous: 2.1, which is the evidence that only small amount of U is present in emission from NTP.
Fig.2. Th and U content in technogenic aerosol, g/t. Designations: aerosol from the vicinity of 1 – NCCP, 2 – HEPP-5, 3 – NTP, 4 – HEPP-2 and HEPP-3; 5 – south and south-east of Novosibirsk vicinity (outside the aureoles of major emissions from industrial enterprises); 6 – background site, 7 – average Th and U content in coal from the Kuznetsky Basin (а) and Kansk-Achinsk Basin (b) and Sereulsky section (c) according to Arbuzov et al. (2008), Arbusov (2009). Geochemical fields: 1 – outside major aureoles of aerosol pollution; 2 – aureoles from HEPP-2 and HEPP-3, 3 – aureole of pollution from HEPP-5.
The geoecological situation in the region of HEPP-5 and NCCP is quite different: these objects are situated at the right bank of the Ob river on a high even plateau at a level of 200 absolute meters, and the chimney of HEPP-5 is one of the highest in Siberia - 260 m. These factors promote unhindered propagation of emissions to the north-east according to the wind rose. The dust content in snow in the vicinity of HEPP-5 and NCCP is about 60 mg/l; with an increase in the distance to the northeast, the dust content of snow decreases to reach 7.2 mg/l at a distance of 50 km, which is comparable with the background dust content (3.14 mg/l) (Fig. 3).
Fig. 3. Dynamics of a decrease in dust content in snow, mg/l (left) and U content in aerosol, ppm (right) with an increase in the distance from NCCP to the northeast (the line shows the trend of change).
The highest concentrations of U and Th were detected in aerosol of the vicinity of NCCP and HEPP-5 and to the north-east from them: up to 9.9 and 16.1 g/t, respectively, with the average concentration of U 5.0 g/t, Th 11.3 g/t. Because of the close location of HEPP-5 and NCCP, the aureoles overlap, so aerosol forms an integrated
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geochemical field No. 3 on the Th-U diagram (Fig. 2). The emissions from which enterprise form so high concentrations of U and Th is aerosol? An answer is to be found within the present work. With an increase in the distance form the city, the concentration of U in aerosol decreases similarly to the dust content in snow (Fig. 3), with the correlation coefficient 0.67. The coefficient of Th correlation with dust content in snow is weaker: only 0.43. The production of fuel elements involves enriched uranium 235U, isotope ratio 238U/235U is best indicator of technogenic nuclear contamination by Tortorello et al.(2013). Natural uranium is a mixture of three isotopes: uranium-238, uranium-235 and uranium-234 at the per cent ratio of 99.2745 : 0.72 : 0.0055, so the natural ratio 238 U/235U is 137.9. Isotopes were studied by means of ICP-MS. Decreased ratio 238U/235U was revealed, which points to permanent pollution of a vicinity of Novosibirsk and surrounding territories with 235U. The source of emissions may be unambiguously only the nuclear fuel plant – NCCP (Fig. 4). The minimal value equal to 77.43 was established in 2011 at a distance of 4.8 km to the northeast from NCCP. With an increase in the distance from NCCP, the ratio 238U/235U increases because of a decrease in the fraction of 235U, therefore, the degree of aerosol pollution by emissions from NCCP decreases (Fig. 4).
Fig. 4. The ratio 238U/235U and U content in technogenic aerosol of Novosibirsk vicinity and the dynamics of its change in the north-eastern direction from NCCP (the line shows the trend of change). For designations, see Fig. 2. The dash line shows the natural 238U/235U ratio.
The maximal length of the aureole of pollution by NCCP in the northeastern direction (along the wind rose) in 2015 was 69.3 km, where the ratio 238U/235U was 132.1, then farther it increased to the natural level of 138.4. The aureole of emissions from NCCP extents also in other directions and somewhat changes from one year to another. For example, in 2005-2006 a decreased ratio 238U/235U equal to 112.8-133.7 was detected at a distance of 14 km to the south near NTP, in 2011 at a distance of 30.5 km to south-east near Klyuchi settlement, though during other years the ratio 238U/235U was natural for these sites. To evaluate the contributions into the total uranium and thorium content in aerosol, the samples of the year 2015 will be chosen. Sampling sites were in the nearest neighborhood of NCCP and HEPP-5. First of all, these are sites 9, 10 (see Fig. 1), which are situated in the park areas to the southwest of NCCP outside the aureole of major pollution by HEPP-5. Second, these are sites 1, 3, situated in the zone affected by the emissions from NCCP and HEPP-5. Third, the site 11 situated under the major influence of emissions from HEPP-5 will be considered. So, aerosol from sites 9, 10 should exhibit the specificity of emissions from NCCP in the most vivid form, while aerosol from sites 11 should exhibit the specificity of emission from HEPP-5, aerosol from sites 1 and 3 should demonstrate the influence of both plants (Fig. 1). In aerosol sampled in 2015, the minimal 238U/235U ratio equal to 93.1 was established exactly for site 9, therefore, the effect of emissions from NCCP is the strongest in this site (Fig. 5, a). In other points except the background one and HEPP-2, HEPP-3 aureoles points (Fig.5, a), the effect of emissions from NCCP is observed: here 238U/235U 104.9–133.7.
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Since HEPP-4 – a satellite of NCCP – is using gas as fuel similarly to HEPP-3, one might expect similar rather low U and Th content in the emissions from HEPP-4. Thorium content in aerosol from site 9 is only 7.2 g/t, which is equal to the average Th content both in aerosol of the aureole of pollution by HEPP-2 and HEPP-3, and in aerosol outside the aureoles of major aerosol pollution in the southern and south-eastern parts of Novosibirsk (Fig. 2, 5).
Fig. 5. The ratio 238U/235U (a), the concentrations, ppm of Th – U (b), Y – Nb (c), Sr – Zr (d) in aerosol. from background site (1), the zone affected by emissions from HEPP-2 and HEPP-3 (mean) (2), from NCCP, sites 9 and 10 (3); from HEPP-5, site 11 and NCCP and HEPP-5 combined influence, sites 1, .3 (5), the data of 2015. Dash line shows the natural 238U/235U ratio. Dot line – boundaries between fallout aureoles.
Therefore, low Th content in aerosol from site 9 confirms the assumption concerning the similarity of emissions from HEPP-4 and HEPP-3, and the absence of significant Th contribution from the emissions of NCCP nuclear-fuel production. At the same time, U content in aerosol from site 9 is 3.8 g/t, which is much higher that the average U content (2.9 g/t) in aerosol from the zone affected by emissions from HEPP-2 and HEPP-3. Therefore, emissions from NCCP nuclear-fuel production bring additional 1 g/t uranium into aerosol (see Fig. 5, b). Among the samples taken in 2015, the lowest ratio Th/U=1.9 is typical for aerosol from site 9. This Th/U ratio is anomalous because the natural ratio is known to be within the range 2.5-5.0, while all the values outside this range are due either to the presence of U (Th) ores or to technogenic pollution by Rikhvanov (2009). Aerosol from site 10 is completely similar to aerosol from site 9, with slightly smaller influence of emissions from NCCP ( 238U/235U= 131.2). Aerosol from sites 1, 3 contain sharply increased Th concentration up (by a factor of about 2) to 12.8 g/t, while U concentration is up (by a factor of 1/4) from 3.8 g/t to 4.9 g/t; so the ratio Th/U increases to 2.6. This effect is also observed in aerosol from site 11 affected directly by the emissions from HEPP-5 (Fig. 5, b). Therefore, increased concentrations of radionuclides Th – 5.6 g/t, U – 1 g/t is due to the emissions from HEPP-5. It is known that the amount of brown coal (from the Sereulsky section of the Kans-Achinsk Basin) burnt every day at HEPP-5 is 10 thousand tons. The average content of U and Th in brown coal from that deposit is 6.7 g/t and 1.2 g/t, respectively by Arbuzov et al. (2008). This means that every day 67 kg of uranium and 12 kg of thorium are burnt. A part of radionuclides gets in emissions and enters the environment. We observe a 4–5-fold increase in Th content from 1.2 g/t in coal to 5.6 g/t in solid aerosol. If the behavior of U were similar to that of Th, we would observe the same increase in U content from 6.7 g/t in initial coal to 27-34 g/t in solid aerosol. However, this does not happen: U concentration in aerosol is only 4.9 g/t. A lack of U in the contribution from HEPP-5 into solid aerosol is observed. The contribution from HEPP-5 into U content is estimated only as 1 g/t. It is known that U in coal is present in scattered form and is bound mainly with the organic substance of coal by Arbuzov (2009), so one might expect aerosol immobilization of U, not less than that for Th. Therefore, the lack of uranium in solid aerosol points to its prevailing mobilization with the gaseous components of emissions, which will be the subject of investigation in forthcoming works. Correlation analysis showed that there is a strong correlation of Zr, Y, Nb, Sr, with U in aerosol, with the coefficient 0.65-86. One can see in Fig. 5 that aerosol from HEPP-5 is enriched with Zr, Y, Nb, Sr, which points to the genetic connection of these elements with the emissions from HEPP-5 and coal fuel (the accumulation of these elements in coal is typical). This fact enhances the difference between emissions from HEPP-5 and solely uranium emissions from NCCP. Investigation of aerosol from NCCP with the help of scanning electron microscope showed that a substantial part of U in the emissions from NCCP is likely to exist in the form of mineral phases of uranium, namely oxides. Solid
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particles of uranium oxides 3 to 64 μm2 in size were found in aerosol of the NCCP emission aureole to northern-east from the NCCP exhibiting the isotope ratio 238U/235U 100.5. The particles have irregular shapes with clear boundaries, often adhered to aluminosilicate matter or hollow spheroids (Fig. 6). Maybe, it is adhesion to light aluminosilicate particles including hollow spheroids that renders high mobility to heavy U particles for long-range
Fig. 6. Particles of uranium oxides in aerosol from the area affected by the emissions from NCCP and the spectrum, and content of U in the particle (electron microscopic images in the mode of back-scattered electrons).
transport with wind. Uranium content in the particles varies within the range 33.83 to 78.80 %, admixtures of Fe – 3.19 %, Cu – 1.23 % are present. The particles of uranium oxides were not found in aerosol from another vicinity of Novosibirsk (they are found only in aerosol of the nearest neighborhood of NCCP and the northern-east area from NCCP), which allows is to relate these particles to the emissions from NCCP. The occurrence of uranium oxides was 3 particles per dust layer with the area of 0.5 cm2 having the mass of ~ 1-2 mg in aerosol from a 10 km range around NCCP. At a distance of 23 km to the northeast from NCCP the occurrence of U microparticles decreases by a factor of 1.5-2. According to the first estimations, within the major plume of emissions from NCCP the density of precipitation of U microparticles (0.n–10 m in size) is 9.5 to 95 .109, or 25 109 particles per 1 km2 per year as average. With the diurnal average technogenic aerosol load of 46 mg/m2*day in a 10 km range around NCCP, the amount of uranium coming with the emission from NCCP per year is about 5.3 kg; in this amount, about 50 g is weapon uranium with the average ratio 238U/235U = 108.8. For the diurnal technogenic aerosol load 57 mg/m 2*day in a 10 km range around HEPP-5, the amount of uranium entering the environment is 6.5 kg per year (together with emission from NCCP this makes 11.8 kg as a total) and 37 kg of thorium. So, the right bank of the Ob in Novosibirsk survives substantial uranium and thorium aerosol load. Conclusion 1. The aureoles of pollution by NCCP and HEPP-5 at the right bank of the Ob are overlapping and extended to the north-east of the city according to the wind rose at a distance not less than 70 km. The aureoles of pollution by HEPP-2, HEPP-3 and NTP are not extended, their length is 1.5-3 km, and the major plume of pollution is limited by the Ob river. 2. The main sources of radioactive aerosol pollution of Novosibirsk and its vicinity are emissions from NCCP and HEPP-5. Aerosol from NCCP contains a mixture of 238U and 235U isotopes, the average isotope ratio 238U/235U in them is
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116.9 (the minimal one is 77.43) instead of the natural value 137.9; Th/U ratio, equal to 1.6–1.9, is anomalously low. In technogenic aerosol from a 10 km range around NCCP, approximately 1 g/t U is formed due to emissions from NCCP. Calculations suggest that every year within this region around NCCP, with the average diurnal technogenic aerosol load of 46 mg/m2*day, the amount of uranium coming with emissions from NCCP is about 5.3 kg; in this amount, 50 g is weapon uranium with the measured average ratio 238U/ 235U equal to 108.8 within this region. Emissions from NCCP bring uranium into the environment not only in the scattered form but also in the form of microparticles of uranium oxides with admixtures of Fe, Cu. With the average frequency of U microparticle occurrence 3 sp/2 mg of aerosol, according to calculations, the number of U microparticles 0.n–10 m in size get precipitated per 1 km2 of the area of 10 km vicinity around NCCP is 25 .109. Uranium microparticles were also found at a distance of 22.8 km to the northeast from NCCP: adhesion of U microparticles to hollow aluminosilicate spheroids may provide their long-range transport with wind. 3. The contribution of the emission from HEPP-5 into technogenic aerosol in the 10 km neighborhood is about 1 g/t U and 5.6 g/t Th. With the diurnal technogenic aerosol load of 57 mg/m 2*day, the annual amounts entering the environment are: uranium - 6.5 kg, thorium - 37 kg. Uranium particles (mineral formations) were not detected in aerosol from HEPP-5. Judging form the composition of fuel (coal) and aerosol, it may be concluded that only a small part of uranium in emissions from HEPP-5 is present in solid aerosol. It is assumed that uranium in the emissions is present mainly in the gaseous form, which is to be established in future studies. The Zr, Nb, Y, Sr are revealed to be the trace-elements of U, Th fallout from HEPP-5 emission. So, the Novosibirsk vicinity on the right bank of the Ob river suffers from substantial technogenic uranium and thorium aerosol load. Acknowledgements The work was supported by the Russian foundation for basic research (RFBR) under project No. 09-05-00839 “Mineral and geochemical features of technogenic aerosol in Siberia” and No.14-05-00289 “Element and mineralphase composition of technogenious aerosol as method basis for an assessment of environmental pollution of the urbanized and mining territories of Siberia”. The part of the work relating to the measurement of spectra was done by analyst Yu.P. Kolmogorov using the infrastructure of the Shared-Use Center “Siberian Synchrotron and Terahertz Radiation Center” (SSTRC) based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. References Arbuzov S.I., Volostnov A.V., Ershov V.V. et al. 2008. Geochemsitry and metal-bearing characteristics of coal from the Krasnoyarsk Territory. – STT, Tomsk, pp. 300. Arbuzov S.I., 2009, Geochemistry of uranium and thorium in coal of Northern Asia, Radioactivity and radioactive elements in the environment: Proceedings of the III International Conference (Tomsk, June 23-27, 2009). Tomsk, Russia, 59–65. Artamonova S.Yu., Lapukhov A.C., Miroshnichenko L.V., Razvorotneva L.I., 2007. Mineral-geochecmial indicators of technogenic sources of aerosol pollution. Chemistry for sustainable development 15, 643–652. Artamonova S.Yu., 2011. Ecology of cities: analysis and evaluation with the help of XFA-SR for Novosibirsk as example. Surface. X-ray, synchrotron and neutron investigations 11, 66–71. Baryshev V., Kulipanov G., Skrinsky A., 1991. X-ray fluorescent elemental analysis. Handbook on Synchrotron Radiation 3 (edited by G. Brown and D.E. Moncton). Elsevier Science Publishers B.V., 641–688. Levichev E.B. Status and perspetives of VEPP-4 complex (in Russian). Particles and Nuclei, Letters, XIII, 7, 2016. Rikhvanov L.P., 2009. Radioactive elements in the environment and the problems of radioecology (A tutorial). STT, Tomsk, pp. 430. The climate of Novosibirsk, 1979. Gidrometeoizdat, Leningrad, pp.221 p. (in Russian). Tortorello R., Widom E., Renwick W.H., 2013. Use of uranium isotopes as a temporal and spatial tracer of nuclear contamination in the environment, Journal of Environmental Radioactivity, 124, 287-300. http://news.ngs.ru/photo/2372183/ A volcano at the Klyuch-Kamyshenskoe plateau (09.02.2016, publication about HEPP-5).
ScienceDirect Physics Procedia 84 (2016) 280 – 287
International Conference "Synchrotron and Free electron laser Radiation: generation and application", SFR-2016, 4-8 July 2016, Novosibirsk, Russia
Technogenic fallout of Uranium and Thorium in the vicinity of Novosibirsk (Russia, West Siberia) Svetlana Yu. Artamonova* V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia
Abstract Evaluation of the contribution of definite pollution sources among many others is rather complicated scientific challenge, but its solution may become decisive for the realization of measures aimed at ecological remediation of the territories. Element composition of aerosol particles accumulated during winter in the snow cover of Novosibirsk was determined by means of X-ray fluorescence measurements with synchrotron radiation at the “Siberian Synchrotron and Terahertz Radiation Center” based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. Means of ICP-MS and scanning electron microscopy were used additionally. These studies allowed revealing the contribution of separate industrial enterprises into the general technogenic pollution of the megapolis with uranium and thorium. © Published by Elsevier B.V. B.V. This is an open access article under the CC BY-NC-ND license ©2016 2016The TheAuthors. Authors. Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility ofthe organizing committee of SFR-2016. Peer-review under responsibility of the organizing committee of SFR-2016.
Keywords: XFA-SR, geochemistry of technogenesis, emission from power plants, emission from nuclear fuel plants, technogenic aerosol, natural radionuclides, uranium isotopes, ecological risk
1. Introduction. Air pollution in industrial cities had become an urgent problem long ago. Investigation of uranium and thorium content in technogenic aerosol is especially urgent because of the risk for human health. Under the conditions of Siberia, snow cover is an ideal object to study geochemistry of technogenesis because of accumulation of aerosol particles and gaseous compounds in it.
* Corresponding author- Svetlana Yu. Artamonova. Tel.: +7-913-700-32-91 fax: +7-383-333-27-91. E-mail address: [email protected]
1875-3892 © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of SFR-2016. doi:10.1016/j.phpro.2016.11.048
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It is known that snow crystals in winter (and raindrops in summer) passing through the air capture solid aerosol particles and gaseous compounds. Also, there is fallout of heavy aerosol particles under gravity. The goal of the work was evaluation of the radioactive uranium-thorium content of technogenic aerosol pollution of Novosibirsk vicinity. Objects of investigation. There are 4 heat-electric generating plants (HEPP) in Novosibirsk (рис.1, a); two of them (HEPP-2 and HEPP-3) are situated at the left bank of the Ob. The nuclear fuel plant – Novosibirsk Chemical Concentrates Plant (NCCP) – produces fuel elements for atomic stations and has its own HEPP-4 similar in parameters with HEPP-3 (see Fig. 1, b). The fuel used at HEPP-2 is mainly black oil, while HEPP-3 and HEPP-4 use natural gas. Only the most powerful (by a factor of 2.5) plant HEPP-5 uses brown coal as fuel: the amount burnt every day is 10000 t by http://news.ngs.ru/photo/2372183/ (2016). Coal is known to be a natural sorbent; it can contain substantial amounts of U and Th, so emission from power plants can also contain these radionuclides. There is also a Tin Plant (NTP) in Novosibirsk; its emission pollutes urban air with As, Sn and a number of other chalcophilic elements by Artamonova et al. (2007, 2011)(see Fig.1, c).
Fig. 1. (a) Location of the industrial enterprises of Novosibirsk. Designations: sampling points: 1 – snow (number), 2 – soil; diffuse aureole of aerosol pollution: 3 – from NCCP, 4 – from HEPP-5, 5 – from NTP, 6 – trace pollution from NTP, 7 – wind rose; (b) The diagram shows the major parameters of HEPP facilities in Novosibirsk: thermal power, Gcal (1), electric power, MW (2), and chimney height, m (3); (c) Dynamics of a decrease in As content in the diffuse aureole of aerosol pollution with an increase in the distance in the north-eastern direction (according to the wind rose) (1), in other directions (2); the content of As in aerosol in the background site (3) (the line shows the trend of changes).
Experimental. The winds of southern and south-western direction dominate in the region under investigation in winter by The climate of Novosibirsk (1979), so the main directions of snow cover sampling were to the north-east of the plants at a distance up to 110 km from the city (Fig. 1, a). The background site was chosen at the windward side at a distance of 12 km in the southwestern direction from the city.
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To exclude the effect of motor roads, sampling was carried out at a distance not less than 200 m. Large-volume snow samples (70 to 200 l) were collected by making shafts through the whole depth of snow cover. Melted snow was filtered through the "blue band" paper filter. The dust content (suspension content, mg/l) was determined as a ratio of the mass of suspension to the volume of melted snow; average diurnal fallout technogenic load (mg/m2*day) was determined as a ratio of suspension mass to the area of sampling and the period of the formation of stable snow cover till sampling date. The concentrations of U, Th and other elements were determined by means of X-ray fluorescence measurements with synchrotron radiation (XFA-SR) at the Siberian Center of synchrotron and terahertz radiation of the Budker Institute of Nuclear Physics SB RAS by Levichev (2016). The lower detection limit is down to 0.1- 0.3 ppm depending on the energy of excitation of emission lines (Table 1). Relative error of XFA-SR is equal or less 15 %. External standard of soil SOIL-7 (International Atomic Energy Agency) was used (analyst: Yu.P. Kolmogorov) by Baryshev et al. (1991). Simple sample preparation allows the analysis of small weighted portions without losses of volatile and other mobile elements, which makes XFA-SR the method of priority to study technogenic aerosol.
V 5 Rb 0.15
Table 1. Lower detection limits of XFA-SR (ppm) A. 23 KeV of primary radiation Cr Mn Fe Ni Cu Zn Ga 4 Sr 0.15
4 Y 0.15
3 Zr 0.15
3 2 1 0.5 Nb Mo Pb Tl 0.15 0.1 0.3 0.2 B. 36.5 KeV of primary radiation Cs Ag Cd Sn Sb 0.2 0.3 0.3 0.2 0.2
Ge
As
Se
Br
0.5 Bi 0.2
0.4 U 0.3
0.3 Th 0.3
0.25
I 0.2
Isotope analysis of 235U, 238U with the relative error < 2 % was carried out using mass spectrometry with inductively coupled plasma (ICP-MS). The samples were preliminarily transferred into solutions by means of melting: 1) with KOH, 2) with LiBO2. Aerosol particles were studied with a scanning electron microscope LEO 1430 VP in the mode of back-scattered electrons. The diameter of scanning beam of the spectrometer was ~ 0.5 μm, which allowed us to determine the composition of aerosol particles up to 0.5-1 μm in size. At the magnification of 1500, not less than 5000 fields of vision 212 X 159 μm in size were examined; each of them contained not less than 300 microparticles. Results and discussion. The strongest snow pollution is observed within 0.5 – 1.5 km range from industrial enterprises, where the dust content of snow was about 60 – 100 mg/l. The aureoles of aerosol pollution from HEPP2, HEPP-3 and NTP at the left bank of the Ob extent at a distance of 1.5–3 km to the north-east and are limited by the Ob river. These enterprises are situated on the lower bank with altitude of 120-130 absolute meters, heights of their chimneys are 100 m. So surface winds along the river valley are likely to make a physical barrier for their emissions (Fig.1). XFA-SR studies showed that the average U content in technogenic aerosol from HEPP-2 and HEPP-3 is not high: 2.9 g/t, Th – 7.2 g/t (Fig.2). In aerosol from NTP, the average Th content is similar to that in the aureole from HEPP-2 and HEPP-3, while U content is slightly higher –3.5 g/t. The concentrations of Th and U in aerosol from HEPP-2, HEPP-3 and NTP are similar to those in aerosol outside the aureoles of major technogenic pollution in the southern and south-eastern vicinity of Novosibirsk, in which the average content of U is 3.0 g/t, Th – 7.6 g/t (Fig. 2). No significant correlation of U and Th content with the elements indicating the emission of NTP (As, Sn and other by Artamonova et al. (2007)) and with the elements indicating emission from HEPP-2, HEPP-3 (Mn, V, I, Ga by Artamonova (2011)) is observed. It is known that the natural Th/U ratio is within the range 2.5–5.0 by Rikhvanov (2009). In the aerosol of the background site, Th content is 8.3 g/t, U – 2.7 g/t, so Th/U is equal to 3.1, which is close to the clarke ratio of the Earth's crust (Fig. 3). The natural Th/U ratio in aerosol of the background site and the minimal dust content in snow (3.14 mg/l) of the background site provide evidence of the successful choice of the background site where the effect of technogenesis is minimal and aerosol is mainly of natural origin. In aerosol outside the major aureoles of technogenic pollution and within the limits of aureoles of HEPP-2 and HEPP-3 the average Th/U ratio is equal to
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2.9, which corresponds to the natural ratio. In the aerosol from NTP, Th/U is anomalous: 2.1, which is the evidence that only small amount of U is present in emission from NTP.
Fig.2. Th and U content in technogenic aerosol, g/t. Designations: aerosol from the vicinity of 1 – NCCP, 2 – HEPP-5, 3 – NTP, 4 – HEPP-2 and HEPP-3; 5 – south and south-east of Novosibirsk vicinity (outside the aureoles of major emissions from industrial enterprises); 6 – background site, 7 – average Th and U content in coal from the Kuznetsky Basin (а) and Kansk-Achinsk Basin (b) and Sereulsky section (c) according to Arbuzov et al. (2008), Arbusov (2009). Geochemical fields: 1 – outside major aureoles of aerosol pollution; 2 – aureoles from HEPP-2 and HEPP-3, 3 – aureole of pollution from HEPP-5.
The geoecological situation in the region of HEPP-5 and NCCP is quite different: these objects are situated at the right bank of the Ob river on a high even plateau at a level of 200 absolute meters, and the chimney of HEPP-5 is one of the highest in Siberia - 260 m. These factors promote unhindered propagation of emissions to the north-east according to the wind rose. The dust content in snow in the vicinity of HEPP-5 and NCCP is about 60 mg/l; with an increase in the distance to the northeast, the dust content of snow decreases to reach 7.2 mg/l at a distance of 50 km, which is comparable with the background dust content (3.14 mg/l) (Fig. 3).
Fig. 3. Dynamics of a decrease in dust content in snow, mg/l (left) and U content in aerosol, ppm (right) with an increase in the distance from NCCP to the northeast (the line shows the trend of change).
The highest concentrations of U and Th were detected in aerosol of the vicinity of NCCP and HEPP-5 and to the north-east from them: up to 9.9 and 16.1 g/t, respectively, with the average concentration of U 5.0 g/t, Th 11.3 g/t. Because of the close location of HEPP-5 and NCCP, the aureoles overlap, so aerosol forms an integrated
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geochemical field No. 3 on the Th-U diagram (Fig. 2). The emissions from which enterprise form so high concentrations of U and Th is aerosol? An answer is to be found within the present work. With an increase in the distance form the city, the concentration of U in aerosol decreases similarly to the dust content in snow (Fig. 3), with the correlation coefficient 0.67. The coefficient of Th correlation with dust content in snow is weaker: only 0.43. The production of fuel elements involves enriched uranium 235U, isotope ratio 238U/235U is best indicator of technogenic nuclear contamination by Tortorello et al.(2013). Natural uranium is a mixture of three isotopes: uranium-238, uranium-235 and uranium-234 at the per cent ratio of 99.2745 : 0.72 : 0.0055, so the natural ratio 238 U/235U is 137.9. Isotopes were studied by means of ICP-MS. Decreased ratio 238U/235U was revealed, which points to permanent pollution of a vicinity of Novosibirsk and surrounding territories with 235U. The source of emissions may be unambiguously only the nuclear fuel plant – NCCP (Fig. 4). The minimal value equal to 77.43 was established in 2011 at a distance of 4.8 km to the northeast from NCCP. With an increase in the distance from NCCP, the ratio 238U/235U increases because of a decrease in the fraction of 235U, therefore, the degree of aerosol pollution by emissions from NCCP decreases (Fig. 4).
Fig. 4. The ratio 238U/235U and U content in technogenic aerosol of Novosibirsk vicinity and the dynamics of its change in the north-eastern direction from NCCP (the line shows the trend of change). For designations, see Fig. 2. The dash line shows the natural 238U/235U ratio.
The maximal length of the aureole of pollution by NCCP in the northeastern direction (along the wind rose) in 2015 was 69.3 km, where the ratio 238U/235U was 132.1, then farther it increased to the natural level of 138.4. The aureole of emissions from NCCP extents also in other directions and somewhat changes from one year to another. For example, in 2005-2006 a decreased ratio 238U/235U equal to 112.8-133.7 was detected at a distance of 14 km to the south near NTP, in 2011 at a distance of 30.5 km to south-east near Klyuchi settlement, though during other years the ratio 238U/235U was natural for these sites. To evaluate the contributions into the total uranium and thorium content in aerosol, the samples of the year 2015 will be chosen. Sampling sites were in the nearest neighborhood of NCCP and HEPP-5. First of all, these are sites 9, 10 (see Fig. 1), which are situated in the park areas to the southwest of NCCP outside the aureole of major pollution by HEPP-5. Second, these are sites 1, 3, situated in the zone affected by the emissions from NCCP and HEPP-5. Third, the site 11 situated under the major influence of emissions from HEPP-5 will be considered. So, aerosol from sites 9, 10 should exhibit the specificity of emissions from NCCP in the most vivid form, while aerosol from sites 11 should exhibit the specificity of emission from HEPP-5, aerosol from sites 1 and 3 should demonstrate the influence of both plants (Fig. 1). In aerosol sampled in 2015, the minimal 238U/235U ratio equal to 93.1 was established exactly for site 9, therefore, the effect of emissions from NCCP is the strongest in this site (Fig. 5, a). In other points except the background one and HEPP-2, HEPP-3 aureoles points (Fig.5, a), the effect of emissions from NCCP is observed: here 238U/235U 104.9–133.7.
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Since HEPP-4 – a satellite of NCCP – is using gas as fuel similarly to HEPP-3, one might expect similar rather low U and Th content in the emissions from HEPP-4. Thorium content in aerosol from site 9 is only 7.2 g/t, which is equal to the average Th content both in aerosol of the aureole of pollution by HEPP-2 and HEPP-3, and in aerosol outside the aureoles of major aerosol pollution in the southern and south-eastern parts of Novosibirsk (Fig. 2, 5).
Fig. 5. The ratio 238U/235U (a), the concentrations, ppm of Th – U (b), Y – Nb (c), Sr – Zr (d) in aerosol. from background site (1), the zone affected by emissions from HEPP-2 and HEPP-3 (mean) (2), from NCCP, sites 9 and 10 (3); from HEPP-5, site 11 and NCCP and HEPP-5 combined influence, sites 1, .3 (5), the data of 2015. Dash line shows the natural 238U/235U ratio. Dot line – boundaries between fallout aureoles.
Therefore, low Th content in aerosol from site 9 confirms the assumption concerning the similarity of emissions from HEPP-4 and HEPP-3, and the absence of significant Th contribution from the emissions of NCCP nuclear-fuel production. At the same time, U content in aerosol from site 9 is 3.8 g/t, which is much higher that the average U content (2.9 g/t) in aerosol from the zone affected by emissions from HEPP-2 and HEPP-3. Therefore, emissions from NCCP nuclear-fuel production bring additional 1 g/t uranium into aerosol (see Fig. 5, b). Among the samples taken in 2015, the lowest ratio Th/U=1.9 is typical for aerosol from site 9. This Th/U ratio is anomalous because the natural ratio is known to be within the range 2.5-5.0, while all the values outside this range are due either to the presence of U (Th) ores or to technogenic pollution by Rikhvanov (2009). Aerosol from site 10 is completely similar to aerosol from site 9, with slightly smaller influence of emissions from NCCP ( 238U/235U= 131.2). Aerosol from sites 1, 3 contain sharply increased Th concentration up (by a factor of about 2) to 12.8 g/t, while U concentration is up (by a factor of 1/4) from 3.8 g/t to 4.9 g/t; so the ratio Th/U increases to 2.6. This effect is also observed in aerosol from site 11 affected directly by the emissions from HEPP-5 (Fig. 5, b). Therefore, increased concentrations of radionuclides Th – 5.6 g/t, U – 1 g/t is due to the emissions from HEPP-5. It is known that the amount of brown coal (from the Sereulsky section of the Kans-Achinsk Basin) burnt every day at HEPP-5 is 10 thousand tons. The average content of U and Th in brown coal from that deposit is 6.7 g/t and 1.2 g/t, respectively by Arbuzov et al. (2008). This means that every day 67 kg of uranium and 12 kg of thorium are burnt. A part of radionuclides gets in emissions and enters the environment. We observe a 4–5-fold increase in Th content from 1.2 g/t in coal to 5.6 g/t in solid aerosol. If the behavior of U were similar to that of Th, we would observe the same increase in U content from 6.7 g/t in initial coal to 27-34 g/t in solid aerosol. However, this does not happen: U concentration in aerosol is only 4.9 g/t. A lack of U in the contribution from HEPP-5 into solid aerosol is observed. The contribution from HEPP-5 into U content is estimated only as 1 g/t. It is known that U in coal is present in scattered form and is bound mainly with the organic substance of coal by Arbuzov (2009), so one might expect aerosol immobilization of U, not less than that for Th. Therefore, the lack of uranium in solid aerosol points to its prevailing mobilization with the gaseous components of emissions, which will be the subject of investigation in forthcoming works. Correlation analysis showed that there is a strong correlation of Zr, Y, Nb, Sr, with U in aerosol, with the coefficient 0.65-86. One can see in Fig. 5 that aerosol from HEPP-5 is enriched with Zr, Y, Nb, Sr, which points to the genetic connection of these elements with the emissions from HEPP-5 and coal fuel (the accumulation of these elements in coal is typical). This fact enhances the difference between emissions from HEPP-5 and solely uranium emissions from NCCP. Investigation of aerosol from NCCP with the help of scanning electron microscope showed that a substantial part of U in the emissions from NCCP is likely to exist in the form of mineral phases of uranium, namely oxides. Solid
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particles of uranium oxides 3 to 64 μm2 in size were found in aerosol of the NCCP emission aureole to northern-east from the NCCP exhibiting the isotope ratio 238U/235U 100.5. The particles have irregular shapes with clear boundaries, often adhered to aluminosilicate matter or hollow spheroids (Fig. 6). Maybe, it is adhesion to light aluminosilicate particles including hollow spheroids that renders high mobility to heavy U particles for long-range
Fig. 6. Particles of uranium oxides in aerosol from the area affected by the emissions from NCCP and the spectrum, and content of U in the particle (electron microscopic images in the mode of back-scattered electrons).
transport with wind. Uranium content in the particles varies within the range 33.83 to 78.80 %, admixtures of Fe – 3.19 %, Cu – 1.23 % are present. The particles of uranium oxides were not found in aerosol from another vicinity of Novosibirsk (they are found only in aerosol of the nearest neighborhood of NCCP and the northern-east area from NCCP), which allows is to relate these particles to the emissions from NCCP. The occurrence of uranium oxides was 3 particles per dust layer with the area of 0.5 cm2 having the mass of ~ 1-2 mg in aerosol from a 10 km range around NCCP. At a distance of 23 km to the northeast from NCCP the occurrence of U microparticles decreases by a factor of 1.5-2. According to the first estimations, within the major plume of emissions from NCCP the density of precipitation of U microparticles (0.n–10 m in size) is 9.5 to 95 .109, or 25 109 particles per 1 km2 per year as average. With the diurnal average technogenic aerosol load of 46 mg/m2*day in a 10 km range around NCCP, the amount of uranium coming with the emission from NCCP per year is about 5.3 kg; in this amount, about 50 g is weapon uranium with the average ratio 238U/235U = 108.8. For the diurnal technogenic aerosol load 57 mg/m 2*day in a 10 km range around HEPP-5, the amount of uranium entering the environment is 6.5 kg per year (together with emission from NCCP this makes 11.8 kg as a total) and 37 kg of thorium. So, the right bank of the Ob in Novosibirsk survives substantial uranium and thorium aerosol load. Conclusion 1. The aureoles of pollution by NCCP and HEPP-5 at the right bank of the Ob are overlapping and extended to the north-east of the city according to the wind rose at a distance not less than 70 km. The aureoles of pollution by HEPP-2, HEPP-3 and NTP are not extended, their length is 1.5-3 km, and the major plume of pollution is limited by the Ob river. 2. The main sources of radioactive aerosol pollution of Novosibirsk and its vicinity are emissions from NCCP and HEPP-5. Aerosol from NCCP contains a mixture of 238U and 235U isotopes, the average isotope ratio 238U/235U in them is
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116.9 (the minimal one is 77.43) instead of the natural value 137.9; Th/U ratio, equal to 1.6–1.9, is anomalously low. In technogenic aerosol from a 10 km range around NCCP, approximately 1 g/t U is formed due to emissions from NCCP. Calculations suggest that every year within this region around NCCP, with the average diurnal technogenic aerosol load of 46 mg/m2*day, the amount of uranium coming with emissions from NCCP is about 5.3 kg; in this amount, 50 g is weapon uranium with the measured average ratio 238U/ 235U equal to 108.8 within this region. Emissions from NCCP bring uranium into the environment not only in the scattered form but also in the form of microparticles of uranium oxides with admixtures of Fe, Cu. With the average frequency of U microparticle occurrence 3 sp/2 mg of aerosol, according to calculations, the number of U microparticles 0.n–10 m in size get precipitated per 1 km2 of the area of 10 km vicinity around NCCP is 25 .109. Uranium microparticles were also found at a distance of 22.8 km to the northeast from NCCP: adhesion of U microparticles to hollow aluminosilicate spheroids may provide their long-range transport with wind. 3. The contribution of the emission from HEPP-5 into technogenic aerosol in the 10 km neighborhood is about 1 g/t U and 5.6 g/t Th. With the diurnal technogenic aerosol load of 57 mg/m 2*day, the annual amounts entering the environment are: uranium - 6.5 kg, thorium - 37 kg. Uranium particles (mineral formations) were not detected in aerosol from HEPP-5. Judging form the composition of fuel (coal) and aerosol, it may be concluded that only a small part of uranium in emissions from HEPP-5 is present in solid aerosol. It is assumed that uranium in the emissions is present mainly in the gaseous form, which is to be established in future studies. The Zr, Nb, Y, Sr are revealed to be the trace-elements of U, Th fallout from HEPP-5 emission. So, the Novosibirsk vicinity on the right bank of the Ob river suffers from substantial technogenic uranium and thorium aerosol load. Acknowledgements The work was supported by the Russian foundation for basic research (RFBR) under project No. 09-05-00839 “Mineral and geochemical features of technogenic aerosol in Siberia” and No.14-05-00289 “Element and mineralphase composition of technogenious aerosol as method basis for an assessment of environmental pollution of the urbanized and mining territories of Siberia”. The part of the work relating to the measurement of spectra was done by analyst Yu.P. Kolmogorov using the infrastructure of the Shared-Use Center “Siberian Synchrotron and Terahertz Radiation Center” (SSTRC) based on VEPP-3 of the Budker Institute of Nuclear Physics SB RAS. References Arbuzov S.I., Volostnov A.V., Ershov V.V. et al. 2008. Geochemsitry and metal-bearing characteristics of coal from the Krasnoyarsk Territory. – STT, Tomsk, pp. 300. Arbuzov S.I., 2009, Geochemistry of uranium and thorium in coal of Northern Asia, Radioactivity and radioactive elements in the environment: Proceedings of the III International Conference (Tomsk, June 23-27, 2009). Tomsk, Russia, 59–65. Artamonova S.Yu., Lapukhov A.C., Miroshnichenko L.V., Razvorotneva L.I., 2007. Mineral-geochecmial indicators of technogenic sources of aerosol pollution. Chemistry for sustainable development 15, 643–652. Artamonova S.Yu., 2011. Ecology of cities: analysis and evaluation with the help of XFA-SR for Novosibirsk as example. Surface. X-ray, synchrotron and neutron investigations 11, 66–71. Baryshev V., Kulipanov G., Skrinsky A., 1991. X-ray fluorescent elemental analysis. Handbook on Synchrotron Radiation 3 (edited by G. Brown and D.E. Moncton). Elsevier Science Publishers B.V., 641–688. Levichev E.B. Status and perspetives of VEPP-4 complex (in Russian). Particles and Nuclei, Letters, XIII, 7, 2016. Rikhvanov L.P., 2009. Radioactive elements in the environment and the problems of radioecology (A tutorial). STT, Tomsk, pp. 430. The climate of Novosibirsk, 1979. Gidrometeoizdat, Leningrad, pp.221 p. (in Russian). Tortorello R., Widom E., Renwick W.H., 2013. Use of uranium isotopes as a temporal and spatial tracer of nuclear contamination in the environment, Journal of Environmental Radioactivity, 124, 287-300. http://news.ngs.ru/photo/2372183/ A volcano at the Klyuch-Kamyshenskoe plateau (09.02.2016, publication about HEPP-5).