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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">gesj</journal-id><journal-title-group><journal-title xml:lang="en">GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY</journal-title><trans-title-group xml:lang="ru"><trans-title>GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2071-9388</issn><issn pub-type="epub">2542-1565</issn><publisher><publisher-name>Russian Geographical Society</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.24057/2071-9388-2019-18</article-id><article-id custom-type="elpub" pub-id-type="custom">gesj-837</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>SPECIAL ISSUE</subject></subj-group></article-categories><title-group><article-title>Relationship Between Major And Trace Elements In Ulaanbaatar Soils: A Study Based On Multivariate Statistical Analysis</article-title><trans-title-group xml:lang="ru"><trans-title></trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Shabanova</surname><given-names>Elena V.</given-names></name></name-alternatives><bio xml:lang="en"><p>Irkutsk</p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Byambasuren</surname><given-names>Ts.</given-names></name></name-alternatives><bio xml:lang="en"><p>Irkutsk</p></bio><email xlink:type="simple">tsagaanbyambasuren@gmail.com</email><xref ref-type="aff" rid="aff-2"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Ochirbat</surname><given-names>G.</given-names></name></name-alternatives><bio xml:lang="en"><p>Ulaanbaatar</p></bio><xref ref-type="aff" rid="aff-3"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Vasil'eva</surname><given-names>Irina E.</given-names></name></name-alternatives><bio xml:lang="en"><p>Irkutsk</p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Khuukhenkhuu</surname><given-names>B.</given-names></name></name-alternatives><bio xml:lang="en"><p>Ulaanbaatar</p></bio><xref ref-type="aff" rid="aff-3"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Korolkov</surname><given-names>Alexei T.</given-names></name></name-alternatives><bio xml:lang="en"><p>Irkutsk</p></bio><xref ref-type="aff" rid="aff-2"/></contrib></contrib-group><aff xml:lang="en" id="aff-1"><institution>A.P. Vinogradov Institute of Geochemistry SB RAS</institution><country>Russian Federation</country></aff><aff xml:lang="en" id="aff-2"><institution>Irkutsk State University</institution><country>Russian Federation</country></aff><aff xml:lang="en" id="aff-3"><institution>Institute of Physics and Technology of MAS</institution><country>Mongolia</country></aff><pub-date pub-type="collection"><year>2019</year></pub-date><pub-date pub-type="epub"><day>14</day><month>10</month><year>2019</year></pub-date><volume>12</volume><issue>3</issue><fpage>199</fpage><lpage>212</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Shabanova E.V., Byambasuren T., Ochirbat G., Vasil'eva I.E., Khuukhenkhuu B., Korolkov A.T., 2019</copyright-statement><copyright-year>2019</copyright-year><copyright-holder xml:lang="ru">Shabanova E.V., Byambasuren T., Ochirbat G., Vasil'eva I.E., Khuukhenkhuu B., Korolkov A.T.</copyright-holder><copyright-holder xml:lang="en">Shabanova E.V., Byambasuren T., Ochirbat G., Vasil'eva I.E., Khuukhenkhuu B., Korolkov A.T.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://ges.rgo.ru/jour/article/view/837">https://ges.rgo.ru/jour/article/view/837</self-uri><abstract><p>This article focuses on the relationships between major (Si, Al, Mg, Fe, Ca, Na, K, S, P and Ti) and potentially toxic trace (Ag, As, B, Ba, Bi, Co, Cd, Cr, Cu, F, Ge, Mo, Mn, Li, Ni, Pb, Sb, Sn, Sr, Tl, V and Zn) elements in Ulaanbaatar surface soils and also sources of the trace elements in the soils distinguished by the methods of multivariate statistical analysis. Results of exploratory data analysis of 325 Ulaanbaatar soil samples show the accumulation of Ca, S, B, Bi, Cu, Mo, Pb, Sb, Sn, Sr and Zn in urban soils. The major elements were grouped by cluster analysis in tree associations characterizing main soil fractions: sandy P-(K-Na-Si), clayey (Mg-Ti-Fe-Al) and silty (S-Ca). The factor analysis shows that silty fraction is enriched in major elements of both natural and anthropogenic origin. The principal component analysis from 32 variables extracted nine principal components with 82.49% of the cumulative explained variance. The results of cluster and factor analyses well agree and reaffirm the enrichment causes of potentially toxic elements are a coal combustion at thermal power stations (B, Bi, Ca, Mo, S and Sr) and traffic emissions (Cu, Pb, Sn and Zn). Spatial distributions of trace elements in the districts of Ulaanbaatar city were obtained by ordinary kriging. It is illustrated that the different principal components define the various origins and patterns of accumulation of trace elements in soils. The supplementation of data set by the concentration of organic carbon and the species of elements could help to identify the sources of such elements as P, Ni, Al, Fe, Ca, Ba, Bi, Cr, Zn, Sr and Sb in urban soils more completely.</p></abstract><kwd-group xml:lang="en"><kwd>urban surface soils</kwd><kwd>major and trace element</kwd><kwd>clayey</kwd><kwd>silty and sandy fractions</kwd><kwd>multivariate statistical analysis</kwd><kwd>ordinary kriging</kwd></kwd-group><funding-group><funding-statement xml:lang="en">The study was fulfilled within the framework of the Agreement on scientific cooperation between the A.P. Vinogradov Institute of Geochemistry of Siberian branch of the Russian Academy of Sciences and Institute of Physics and Technology of the Mongolia Academy of Sciences.</funding-statement></funding-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Amgalan N., Narantsetseg T. and Shagjjamva D. (2016). Valuations of elemental concentrations of particle matter in Ulaanbaatar, Mongolia. Open Journal of Air Pollution, 5(4), pp. 160-169. doi: 10.4236/ojap.2016.54012</mixed-citation><mixed-citation xml:lang="en">Amgalan N., Narantsetseg T. and Shagjjamva D. (2016). Valuations of elemental concentrations of particle matter in Ulaanbaatar, Mongolia. Open Journal of Air Pollution, 5(4), pp. 160-169. doi: 10.4236/ojap.2016.54012</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Armstrong M. (1998). Basic Linear Geostatistics. Springer-Verlag Berlin Heidelberg GmbH.</mixed-citation><mixed-citation xml:lang="en">Armstrong M. (1998). Basic Linear Geostatistics. Springer-Verlag Berlin Heidelberg GmbH.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Batkhishig O. (1999). Extended Abstract of Candidate’s Dissertation in Geography. Ulaanbaatar (in Russian).</mixed-citation><mixed-citation xml:lang="en">Batkhishig O. (1999). Extended Abstract of Candidate’s Dissertation in Geography. Ulaanbaatar (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Byambasuren Ts., Shabanova E.V., Korolkov A.T., Vasilyeva I.E., Ochirbat G. and Khuukhenkhuu B. (2018). Distribution of Trace Elements in Soils of Ulaanbaatar. The Bulletin of Irkutsk State University. Series Earth Sciences, 26, pp. 31-45. (in Russian with English summary)</mixed-citation><mixed-citation xml:lang="en">Byambasuren Ts., Shabanova E.V., Korolkov A.T., Vasilyeva I.E., Ochirbat G. and Khuukhenkhuu B. (2018). Distribution of Trace Elements in Soils of Ulaanbaatar. The Bulletin of Irkutsk State University. Series Earth Sciences, 26, pp. 31-45. (in Russian with English summary)</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Capital statistics. (2018). Official Website. [online] Available at: http://www.ubstat.mn/ [Accessed 01 Oct. 2018] (in Mongolian).</mixed-citation><mixed-citation xml:lang="en">Capital statistics. (2018). Official Website. [online] Available at: http://www.ubstat.mn/ [Accessed 01 Oct. 2018] (in Mongolian).</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Chai Y., Guo J., Chai Sh., Cai J., Xue L.and Zhang Q. (2015). Source identification of eight heavy metals in grassland soils by multivariate analysis from the Baicheng-Songyuan area, Jilin Province, Northeast China. Chemosphere, 134, pp. 67-75. doi: 10.1016/j.chemosphere.2015.04.008</mixed-citation><mixed-citation xml:lang="en">Chai Y., Guo J., Chai Sh., Cai J., Xue L.and Zhang Q. (2015). Source identification of eight heavy metals in grassland soils by multivariate analysis from the Baicheng-Songyuan area, Jilin Province, Northeast China. Chemosphere, 134, pp. 67-75. doi: 10.1016/j.chemosphere.2015.04.008</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Chen T., Liu X.M., Zhu M.Z., Zhao K.L., Wu J.J., Xu J.M. and Huang P. (2008). Identification of trace element sources and associated risk assessment in vegetable soils of the urbanrural transitional area of Hangzhou, China. Environmental Pollution, 151(1), pp. 67-78. doi: 10.1016/j.envpol.2007.03.004</mixed-citation><mixed-citation xml:lang="en">Chen T., Liu X.M., Zhu M.Z., Zhao K.L., Wu J.J., Xu J.M. and Huang P. (2008). Identification of trace element sources and associated risk assessment in vegetable soils of the urbanrural transitional area of Hangzhou, China. Environmental Pollution, 151(1), pp. 67-78. doi: 10.1016/j.envpol.2007.03.004</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Chou C.-L. (2012). Sulfur in coals: A review of geochemistry and origins. International Journal of Coal Geology, 100, pp. 1-13. doi: 10.1016/j.coal.2012.05.009</mixed-citation><mixed-citation xml:lang="en">Chou C.-L. (2012). Sulfur in coals: A review of geochemistry and origins. International Journal of Coal Geology, 100, pp. 1-13. doi: 10.1016/j.coal.2012.05.009</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Christensen E.R., Steinnes E. and Eggen O.A. (2018). Anthropogenic and geogenic mass input of trace elements to moss and natural surface soil in Norway. Science of the Total Environment, 613-614, pp. 371-378. doi: 10.1016/j.scitotenv.2017.09.094</mixed-citation><mixed-citation xml:lang="en">Christensen E.R., Steinnes E. and Eggen O.A. (2018). Anthropogenic and geogenic mass input of trace elements to moss and natural surface soil in Norway. Science of the Total Environment, 613-614, pp. 371-378. doi: 10.1016/j.scitotenv.2017.09.094</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Erdenetsogt B.-O., Lee I., Bat-Erdene D. and Jargal L. (2009). Mongolian coal-bearing basins: Geological settings, coal characteristics, distribution, and resources. International Journal of Coal Geology, 80, pp. 87-104. doi: 10.1016/j.coal.2009.08.002</mixed-citation><mixed-citation xml:lang="en">Erdenetsogt B.-O., Lee I., Bat-Erdene D. and Jargal L. (2009). Mongolian coal-bearing basins: Geological settings, coal characteristics, distribution, and resources. International Journal of Coal Geology, 80, pp. 87-104. doi: 10.1016/j.coal.2009.08.002</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Facchinelli A., Sacchi E. and Mallen L. (2001). Multivariate statistical and GIS-based approach to identify heavy metal sources in soils. Environmental Pollution, 114, pp. 313-324. doi: 10.1016/S0269-7491(00)00243-8</mixed-citation><mixed-citation xml:lang="en">Facchinelli A., Sacchi E. and Mallen L. (2001). Multivariate statistical and GIS-based approach to identify heavy metal sources in soils. Environmental Pollution, 114, pp. 313-324. doi: 10.1016/S0269-7491(00)00243-8</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Gunicheva T. (2012). Application of nondestructive X-Ray fluorescence method (XRF) in soils, friable and marine sediments and ecological materials. In: Panagiotaras D., ed., Geochemistry – Earth's System Processes. InTech, pp. 371-388. Available from: http://www.intechopen.com/books/geochemistry-earth-s-system-processes/application-ofnondestructive-wavelength-dispersive-x-ray-fluorescence-wd-xrf-method-in-soils-friabl [Accessed 09 Feb. 2019].</mixed-citation><mixed-citation xml:lang="en">Gunicheva T. (2012). Application of nondestructive X-Ray fluorescence method (XRF) in soils, friable and marine sediments and ecological materials. In: Panagiotaras D., ed., Geochemistry – Earth's System Processes. InTech, pp. 371-388. Available from: http://www.intechopen.com/books/geochemistry-earth-s-system-processes/application-ofnondestructive-wavelength-dispersive-x-ray-fluorescence-wd-xrf-method-in-soils-friabl [Accessed 09 Feb. 2019].</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">ISO 10381-2008: Soil quality, Sampling, Part 1-5: Guidance on the procedure for the investigation of urban and industrial sites with regard to soil contamination.</mixed-citation><mixed-citation xml:lang="en">ISO 10381-2008: Soil quality, Sampling, Part 1-5: Guidance on the procedure for the investigation of urban and industrial sites with regard to soil contamination.</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Kabata-Pendias A. (2011). Trace elements in soils and plants. 4th ed. CRC Press, Boca Raton, FL, 2011.</mixed-citation><mixed-citation xml:lang="en">Kabata-Pendias A. (2011). Trace elements in soils and plants. 4th ed. CRC Press, Boca Raton, FL, 2011.</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Kasimov N.S., Kosheleva N.E., Sorokina O.I., Bazha S.N., Gunin P.D. and Enkh-Amgalan S. (2011). Ecological-geochemical state of soils in Ulaanbaatar (Mongolia). Eurasian Soil Science, 44(7), pp. 709-721. doi: 10.1134/S106422931107009X</mixed-citation><mixed-citation xml:lang="en">Kasimov N.S., Kosheleva N.E., Sorokina O.I., Bazha S.N., Gunin P.D. and Enkh-Amgalan S. (2011). Ecological-geochemical state of soils in Ulaanbaatar (Mongolia). Eurasian Soil Science, 44(7), pp. 709-721. doi: 10.1134/S106422931107009X</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Kosheleva N.E., Kasimov N.S. and Vlasov D.V. (2015). Factors of the Accumulation of Heavy Metals and Metalloids at Geochemical Barriers in Urban Soils. Eurasian Soil Science, 48(5), pp. 476-492. doi: 10.1134/S1064229315050038</mixed-citation><mixed-citation xml:lang="en">Kosheleva N.E., Kasimov N.S. and Vlasov D.V. (2015). Factors of the Accumulation of Heavy Metals and Metalloids at Geochemical Barriers in Urban Soils. Eurasian Soil Science, 48(5), pp. 476-492. doi: 10.1134/S1064229315050038</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Lee C.S., Li X., Shi W., Cheung S.C. and Thornton I. (2006). Metal contamination in urban, suburban and country park soils of Hong Kong: a study based on GIS and multivariate statistics. Science of The Total Environment, 356(1-3), pp. 45-61. doi: 10.1016/j.scitotenv.2005.03.024</mixed-citation><mixed-citation xml:lang="en">Lee C.S., Li X., Shi W., Cheung S.C. and Thornton I. (2006). Metal contamination in urban, suburban and country park soils of Hong Kong: a study based on GIS and multivariate statistics. Science of The Total Environment, 356(1-3), pp. 45-61. doi: 10.1016/j.scitotenv.2005.03.024</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Luo X.-S., Xue Y., Wang Y.-L., Cang L., Xu B. and Ding J. (2015). Source identification and apportionment of heavy metals in urban soil profiles. Chemosphere. 127, pp. 152-157. doi: 10.1016/j.chemosphere.2015.01.048</mixed-citation><mixed-citation xml:lang="en">Luo X.-S., Xue Y., Wang Y.-L., Cang L., Xu B. and Ding J. (2015). Source identification and apportionment of heavy metals in urban soil profiles. Chemosphere. 127, pp. 152-157. doi: 10.1016/j.chemosphere.2015.01.048</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Maurice P.A. (2009). Environmental surfaces and interfaces from the nanoscale to the global scale. John Wiley &amp; Sons, Inc.</mixed-citation><mixed-citation xml:lang="en">Maurice P.A. (2009). Environmental surfaces and interfaces from the nanoscale to the global scale. John Wiley &amp; Sons, Inc.</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Norra S., Lanka-Panditha M., Kramar U. and Stüben D. (2006). Mineralogical and geochemical patterns of urban surface soils, the example of Pforzheim, Germany. Applied Geochemistry, 21, pp. 2064-2081. doi: 10.1016/j.apgeochem.2006.06.014</mixed-citation><mixed-citation xml:lang="en">Norra S., Lanka-Panditha M., Kramar U. and Stüben D. (2006). Mineralogical and geochemical patterns of urban surface soils, the example of Pforzheim, Germany. Applied Geochemistry, 21, pp. 2064-2081. doi: 10.1016/j.apgeochem.2006.06.014</mixed-citation></citation-alternatives></ref><ref id="cit21"><label>21</label><citation-alternatives><mixed-citation xml:lang="ru">Soil cover and soils of Mongolia. (1984). In: I.P. Gerasimov, N.A. Nogina, Dorjgotov D., ed. Moscow: Science. (in Russian).</mixed-citation><mixed-citation xml:lang="en">Soil cover and soils of Mongolia. (1984). In: I.P. Gerasimov, N.A. Nogina, Dorjgotov D., ed. Moscow: Science. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit22"><label>22</label><citation-alternatives><mixed-citation xml:lang="ru">Steinnes E. and Lierhagen S. (2018). Geographical distribution of trace elements in natural surface soils: Atmospheric influence from natural and anthropogenic sources. Applied Geochemistry, 88, pp. 2-9. doi: 10.1016/j.apgeochem.2017.03.013</mixed-citation><mixed-citation xml:lang="en">Steinnes E. and Lierhagen S. (2018). Geographical distribution of trace elements in natural surface soils: Atmospheric influence from natural and anthropogenic sources. Applied Geochemistry, 88, pp. 2-9. doi: 10.1016/j.apgeochem.2017.03.013</mixed-citation></citation-alternatives></ref><ref id="cit23"><label>23</label><citation-alternatives><mixed-citation xml:lang="ru">Vasil'eva I.E. and Shabanova E.V. (2012). Arc atomic-emission analysis in geochemical research. Industrial laboratory. Diagnostics of materials, 78(1-II), pp. 14-24. (in Russian with English summary).</mixed-citation><mixed-citation xml:lang="en">Vasil'eva I.E. and Shabanova E.V. (2012). Arc atomic-emission analysis in geochemical research. Industrial laboratory. Diagnostics of materials, 78(1-II), pp. 14-24. (in Russian with English summary).</mixed-citation></citation-alternatives></ref><ref id="cit24"><label>24</label><citation-alternatives><mixed-citation xml:lang="ru">Vasilyeva I.E., Shabanova E.V., Doroshkov A.A., Proydakova O.A., Otgontuul Ts., Khuukhtnkhuu B., Byambasuren Ts. (2013) Distribution of toxic and essential elements in soils of Ulaanbaatar city. Environment and sustainable development in Mongolian plateau and surrounding regions, vol. 1, pp. 67-71. Available at: https://docs.google.com/viewer?a=v&amp;pid=sites&amp;srcid=ZGVmYXVsdGRvbWFpbnxtb25wbGF0ZWF1MjAxM3xneDoyMzJjMWJlNjRmNTU3NmM [Accessed 09 Feb. 2019].</mixed-citation><mixed-citation xml:lang="en">Vasilyeva I.E., Shabanova E.V., Doroshkov A.A., Proydakova O.A., Otgontuul Ts., Khuukhtnkhuu B., Byambasuren Ts. (2013) Distribution of toxic and essential elements in soils of Ulaanbaatar city. Environment and sustainable development in Mongolian plateau and surrounding regions, vol. 1, pp. 67-71. Available at: https://docs.google.com/viewer?a=v&amp;pid=sites&amp;srcid=ZGVmYXVsdGRvbWFpbnxtb25wbGF0ZWF1MjAxM3xneDoyMzJjMWJlNjRmNTU3NmM [Accessed 09 Feb. 2019].</mixed-citation></citation-alternatives></ref><ref id="cit25"><label>25</label><citation-alternatives><mixed-citation xml:lang="ru">Vodyanitskii Yu.N. (2008). Heavy metals and metalloids in soils. Moscow: V.V. Dokuchaev Soil science Institute. (in Russian).</mixed-citation><mixed-citation xml:lang="en">Vodyanitskii Yu.N. (2008). Heavy metals and metalloids in soils. Moscow: V.V. Dokuchaev Soil science Institute. (in Russian).</mixed-citation></citation-alternatives></ref><ref id="cit26"><label>26</label><citation-alternatives><mixed-citation xml:lang="ru">Wei B.G. and Yang L.S. (2010). A review of heavy metal contaminations in urban soils, urban road dusts and agricultural soils from China. Microchemical Journal, 94(2), pp. 99-107. doi: 10.1016/j.microc.2009.09.014</mixed-citation><mixed-citation xml:lang="en">Wei B.G. and Yang L.S. (2010). A review of heavy metal contaminations in urban soils, urban road dusts and agricultural soils from China. Microchemical Journal, 94(2), pp. 99-107. doi: 10.1016/j.microc.2009.09.014</mixed-citation></citation-alternatives></ref><ref id="cit27"><label>27</label><citation-alternatives><mixed-citation xml:lang="ru">Wong C.S.C., Li X. and Thornton I. (2006). Urban environmental geochemistry of trace metals. Environmental Pollution, 142(1), pp. 1-16. doi: 10.1016/j.envpol.2005.09.004</mixed-citation><mixed-citation xml:lang="en">Wong C.S.C., Li X. and Thornton I. (2006). Urban environmental geochemistry of trace metals. Environmental Pollution, 142(1), pp. 1-16. doi: 10.1016/j.envpol.2005.09.004</mixed-citation></citation-alternatives></ref><ref id="cit28"><label>28</label><citation-alternatives><mixed-citation xml:lang="ru">Zinkutė R., Taraškevičius R. and Želvys T. (2011). Major elements as possible factors of trace element urban pedochemical anomalies. Central European Journal of Chemistry, 94(2), pp. 337-347. doi: 10.2478/s11532-011-0012-z</mixed-citation><mixed-citation xml:lang="en">Zinkutė R., Taraškevičius R. and Želvys T. (2011). Major elements as possible factors of trace element urban pedochemical anomalies. Central European Journal of Chemistry, 94(2), pp. 337-347. doi: 10.2478/s11532-011-0012-z</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
