Radiation biology. Radioecology
ISSN: 0869-8031

Archives → 2018 → Vol. 58, No. 1 → pp. 59-73

Article

Assessing Contamination Levels of “Experimental Field” Ground with Technogenic Uranium at the Semipalatinsk Test Site

Koigeldinova M.T.¹, Lukashenko S.N.¹, Mukhamediyarov N. Zh.¹, Umarov M.A.¹

¹Branch "Institute of Radiation Safety and Ecology" RSE "National Nuclear Center" of the Republic of Kazakhstan, Kurchatov, Kazakhstan

Abstract

For the first time this article gives generalized results of the uranium concentration and its isotope composition (²³⁵U and ²³⁸U) in the soil cover of the main sites of the «Experimental Field» ground. As a result of the research, spots contaminated with technogenic uranium are identified, whose isotope composition changes to enrichment or depletion in ²³⁵U. Experimental data confirmed that in implementation of hydronuclear experiments, the territories of some spots at P-2, P-5 and P-7 sites were significantly contaminated with highly enriched dispersed ²³⁵U. The vertical distribution of technogenic uranium is studied at the most contaminated spots. The information obtained on distribution of the uranium concentration at a depth will be of use for the development of measures aimed at remediation of the soil contamination. Remediation work at U-1 site must be performed at a depth of at least 30 cm, at P-2-P-7 sites — at a depth of at least 20 cm. Contamination with depleted uranium is of the local type in the form in placers of uranium oxide fragments, which are bright yellow and yellow-green. Speciation of technogenic uranium is studied in the soils of the «Experimental Field» ground of the Semipalatinsk test site. Uranium hardly ever passed into easily accessible forms for plants — aqueous extract and exchangeable form. However, technogenic uranium in contaminated soils is characterized by a high degree of potential mobility revealed by 1 N solution hydrochloric acid.