EFFECTS ON HUMAN HEALTH Biogechemistry of Uranium and Thorium N.V. Baranovskaya *, L.P. Rikhvanov, B.R. Soktoyev

Geoecology and Geochemistry Department, Polytechnic University, Lenina St., 30, Tomsk, , * [email protected]

Abstract The peculiarities in thorium and uranium distribution in various media (soil, drinking water, scale, hair, blood, biopsic specimen of pathologically changed thyroid gland) from 16 regions of of Russian have been analyzed. Besides, the values of their concen- trations and Th/U relations have been stated for indication of changes in conditions of not only outside an organism but also inside it. The basic research method is neuron-activation analysis made in the nuclear-geochemical laboratory of the Geoecology and Geochemistry Department. The analysis of spatial distribution of radioactive elements over the territory of Tomsk Oblast as well as region ranking indicators of system interaction allows for reveling different mechanisms of entry, distribution, and accumulation of uranium and thorium in living systems. Their accumulation in accumulative media - hair, in pathological thyroid forms - indicates the fact that the elements entering with water, from soil via trophic chain or air are not excreted, but stay in the organism. Key words: Uranium, thorium, environment, living system, biogeochemistry

Introduction ied, which is a large gap in ecogeochemistry Thorium and uranium reoffered to the (Ivanov, 1997). group of actinides has been known along with protactinium as early as at the begin- Materials and methods ning of the past century (Greenwood and We have analyzed features of thorium Ernshoe, 2008). The concept about chem- and uranium distribution in different envi- istry, occurrence and behavior of these natu- ronment of 16 regions in Tomsk oblast. ral nuclides was developed mostly in terms Besides, the index values of their concentra- of advancement of nuclear engineering and tion and Th/U relationship for reveling achievements in chemistry. At present we changes in conditions of not only outside the have some information on their chemical organism but also inside it was stated. properties (Spitsyn and Martynenko, 1991), The following objects were investigat- geochemical behavior in different types of ed: soil (192 samples), drinking water (93 soil, rocks and indicators (Yevseeva and samples) and scale (salt depositions in Perelman, 1962; Kabata-Pendias and Pen- houseware) (293 samples), organs and tis- dias, 1989; Titayeva, 2000; Rikhvanov, sues of human organism (bioptic specimen 2002) as well as on their influence on living of transformed thyroid gland (114 samples), organisms (Hoffman, 1943; Balabukha and hair (560 samples), blood (255 samples). All Fradkin, 1958; Rassel, 1971; Moiseev and objects were selected in accordance with Ivanov, 1984; Baranovskaya, 2009). specified techniques and analyzed with Nevertheless, the problem of quantita- method of neutron activation analysis after tive content of these elements in the seg- preliminary sample preparation in the ments of living environment as well as bio- research laboratory of nuclear-geochemical geochemical aspects of their behavior have methods of Geoecology and Geochemistry not been studied yet up to now. Presumably, Department, Tomsk Polytechnic University this fact is explained to a considerable extent by A.F. Sudyko, analyst. by the analytical difficulties of their determi- nation in living substance (LS). Contempo- Results and Discussion rary kinds of analysis are favorable to accu- Analysis of spatial distribution of mulation of information on content of these chemical elements in various media in the elements in different natural objects. territory of Tomsk Oblast has shown that The urgency of such research is condi- zones of their elevated concentrations in tioned by the fact that chemical toxicology water, scale, and soil, as a rule, coincide with has not been virtually investigated, radiation those stated by the results of accumulation toxicology of those elements being well stud- in living substance - hair, blood and bioptic

15 th ICHMET 891 EFFECTS ON HUMAN HEALTH material of pathologically changed thyroid carbon water composition is likely to result glands. But in this case there are some pecu- in fluid uranyl-carbonate complexes etc.). liarities. Thus, elevated uranium concentra- Thorium does not show such migra- tion in blood, thyroid glands, water and scale tion capacity in this region. It is inert, and in in some regions of the oblast has a reversed its distribution map it is characterized by low character in comparison with their accumu- accumulation level nearly in all media. Sim- lation in soil and hair. ilar conditions are likely to be typical for The maximum high concentrations of Bakhchar, Asino, and Teguldet regions. this element in pathologically changed thy- Tomsk region is characterized by thorium roid glands are of linear zone character with accumulation in different media against the South -North direction through the territory background of uranium water migration of Tomsk region characterized by the com- close to one. plex anthropogenic load. Presumably, increase in fluid uranium High thorium concentrations are also con- forms is reflected in its significant accumula- nected with the territory of Tomsk region and tion in blood of the population living in these typical for soil, blood, hair, and thyroid gland, territories, that defines the region differenti- but are not the case for drinking water scale. ation according to radioelement relationship Such features in element distribution in "water - blood" system and "hair - blood", result in the conclusion on migration of "blood - thyroid gland" biosystems (Fig.2). investigated elements in different forms Special location of Zyryansk region along the "environment - living organism" (7 in all graphs) with high concentration of chain. In fact, the intensity of uranium and uranium in such media as water and blood thorium intake into living systems depends proves the data on significant intensity of on the kind of chemical compounds (Th +4 , the element migration and its possible U+4 , U +6 ), medium conditions (Eh, pH), intake with drinking water. For several resi- ways of their intake (breathing or along the dential areas of this region the presence of food chain), as well as properties of living high uranium content in water has been system itself and some other factors. Analy- known before, which probably comes into it sis of Th/U ration distribution in children's from brown coals enriched with this compo- hair composition of Tomsk oblast has shown nent (Rikhvanov, 1997). Lower concentra- that in contrast to other media its values tions in hair and thyroid glands indicate that higher than 0,7 are typical for narrow zone in it is most likely to be a form of element in the territory of Tomsk oblast connected with which it is excreted from organism and not the zone of Siberian Chemical Combine accumulated in depository media. impact - a nuclear fuel cycle plant. Taking Of particular interest is the fact that into consideration the prevailing direction of the residential areas are divided into three wind transfer one could suggest that such a main groups of linear character in terms of pattern of distribution is most likely features of uranium accumulation in water explained by the effect of air constituent and human hair depending on its concentra- reflected in hair composition. Besides, this tions in these media. value is high not due to thorium constituent, It should be noted that for Tomsk region against the background of both high urani- significant element concentrations are um and thorium concentrations with some observed in thyroid tissue composition. That predominance of the latter in separate sites. may be connected with selective uranium To solve the problem of potential accumulation (Denisova et al., 2009) or pecu- mechanism of element entry to living sys- liarities of its intake in this region, as the accu- tem we calculated the water migration coef- mulation analysis of residual areas shows that ficient by Yevseeva and Perelman (1962) for the highest content is determined in composi- uranium. This index allowed for the state- tion of thyroid glands of residents from samus ment of the fact that its maximum intensity settlement as well as town located in is typical for Zyraynsk region of Tomsk the SCC impact zone. oblast (Fig.1). One could assume that on the Influence of Alexandrovo and Kargasok territory there is a favorable geochemical region location of Tomsk oblast in the analy- environment for more active uranium sis of "blood - hair" system permits the sug- migration (elevated concentrations connect- gestion of prevailing other uranium intake ed with lignite in the zone of aeration, hydro- mechanisms in living systems in compari- son with those in Zyryansk region. These

892 15 th ICHMET EFFECTS ON HUMAN HEALTH

Figure 1 . Coefficient of uranium water migration in the regions of Tomsk oblast. Rregions: 1 - Tomsk, 2 - Asino, 5 - Shegarsk, 6 - Teguldet, 7 - Zyryansk, 8 - Parabel, 9 - Bakhchar, 10 - , 11 - Verkhneketsk, 14 -Pervomayskiy.

Figure 2. Ranking regions of Tomsk oblast in terms of uranium relationship in different media: 1 - 16 - regions: 1 - Tomsk, 2 - Asino, 3 - Chainsk, 4 - Krivosheino, 5 - Shegarsk, 6 - Teguldet, 7 - Zyryansk, 8 - Parabel, 9 - Bakhchar, 10 - Kolpashevo, 11 - Verkhneketsk, 12 - Alexandrovo, 13 - Kargasok, 14 -Pervomayskiy, 15 - Kozhevnikovo, 16 - Molchanovo.

15 th ICHMET 893 EFFECTS ON HUMAN HEALTH regions are described as oil-and-gas bearing Denisova A.A., Baranovskaya N.V., ones that is likely to be reflected in features Chernogoryuk G.E., Kalyanov ?.V. Uranium of uranium accumulation in living system and thorium in the tissue of thyroid gland of composition in these areas. Tomsk oblast // Materials of the III Interna- tional conference "Radioactivity and radioac- Conclusion tive elements in human environment", Therefore, the analysis of data on spa- Tomsk, 23-27, June, 2009. - Tomsk: STT, tial distribution of radioactive elements over 2009.- P.161 - 163. the territory of Tomsk oblast as well as indi- Ivanov V.V Ecological geochemistry of cators of region ranking in terms of system elements: Manual: In 6 Books/ Edited by interaction allows for suggestion of different E.A. Burenkov. - Moscow: Ecologiya, 1997. - intake, distribution, and accumulation Book 6: Rare f - elements. - 607 p. mechanisms for uranium and thorium in Hoffman J. Bioelement Uran im living systems. Their accumulation in Pflanzen - und Tierreich sowie im men- depository systems - hair, pathological forms schlichen Organismus. // Biochemische of thyroid glands points to the fact that the Zeitschrift, Bd. 313, 5-6 Heft, Berlin, elements entering with water, air, from soil Springer - Verl., 1943. - S. 377 - 387. along the food chains, are not excreted from Yevseeva L.S., Perelman ?.I. Uranium organism, but stay in it. This fact requires geochemistry in the hypergenesis zone. - for special analysis of medical health indica- Moscow: Gosatomizdat, 1962. - 239 p. tors in these regions, since uranium is Kabata-Pendias A., Pendias Ch. known as a renal poison, but thorium has Microelements in soil and plants.-Moscow: capacity of respiratory depression, hence, Mir, 1989. - 439 p. one could assume a higher specific disease Moiseev A.A., Ivanov V.I. Manual on rate for population. Therefore, it is necessary dosimetry and radiation hygiene. - Moscow: to arrange the prophylaxis of population dis- Energoatomizdat, 1984. - 296 p. ease in such areas. Radioactivity and human food / Edited by Rassel. Translated from English. Ed. by References V.A. Klechkovskiy. - Moscow: Atomizdat, Balabukha V.S., Fradkin G.Ye. Accu- 1971. - 376 p. mulation of radioactive elements in the Rikhvanov L.P. General and regional organism and their excretion. - Moscow: problems of radioecology. - Tomsk: Tomsk State Publishing House of Medical Litera- polytechnic university press, 1997. - 384 p. ture - Medgis, 1958. - 184 p. Rikhvanov L.P. Radiogeochemical Baranovskaya N.V. On actinides in liv- typology of ore-magmatic formations (by the ing substance. // Materials of the III Interna- example of Altay-Sayan fault region) / Edited tional conference "Radioactivity and radioac- by I.V. Kucherenko. - Novosibirsk: RAS SB tive elements in human environment", Publishing House, "Geo", 2002. - 536 p. Tomsk, 23-27, June, 2009. - Tomsk: STT, Titayeva N.A. Nuclear geochemistry. - 2009.- P.73 - 82. Moscow: Moscow University Press, 2000. - Greenwood N., Ernshoe A. Chemistry 336 p. of elements: in 2 Vol. /Translated from Eng- lish. - Moscow: BINOM. Laboratoriya znaniy, 2008. - V.2. - 670 p.

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