en Medical Physics Medical Physics تحقيق بديع Original Research ABSTRACT<br> Background: This work investigated radioactive contamination in soils of the pine forest in the territory adjacent to Semipalatinsk test site. Materials and Methods: Thirty samples from the soil were collected from six different a soil profile was laid out (research areas). Activity concentrations of ¹³⁷Cs and ²⁴¹Am were determined using a Canberra GX-2020 solid-state gamma-spectrometer system. Activity concentrations of ⁹⁰Sr and ^239+240Pu were determined after application of radiochemical analysis. In addition, the soil physicochemical characteristics such as pH value, the amount of organic content and texture of soil were investigated by pH meter, the Tiurin&rsquo;s techniques, modified by Nikitin, and particle size distribution (Pipette) methods, respectively. Results: The highest specific activity values were registered for ²⁴¹Am (up to 64 Bq/kg) and ^239+240Pu (up to 75 Bq/kg) transuranium radionuclides. Maximum concentrations of ²⁴¹Am, ¹³⁷Cs and ^239+240Pu were registered in the top 5-cm layer, while ⁹⁰Sr is uniformly distributed up to the depth of 20 cm. In general, researched artificial radionuclides by their level of mobility in vertical soil profile can be arranged in sequence as follows: ⁹⁰Sr > ^239+240Pu > ²⁴¹Am > ¹³⁷Cs. Conclusion: ¹³⁷Cs by the character of its distribution in vertical soil profile is similar to its vertical distribution in brown soils at conditionally &laquo;background&raquo; STS territories. Mobility of ²⁴¹Am, ^239+240Pu and ⁹⁰Sr in brown soils at the researched territory is higher than at conditionally &laquo;background&raquo; territories of the STS. Semipalatinsk Test Site (STS), artificial radionuclides, cesium (137-Cs), strontium (90-Sr), americium (241-Am), plutonium (239+24-0Pu), soil. 113 120 http://ijrr.com/browse.php?a_code=A-10-2055-92&slc_lang=en&sid=1 N.V.  Larionova larionova@nnc.kz 7900319475328460019981 7900319475328460019981 Yes Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan A.V.  Panitskiy 7900319475328460019982 7900319475328460019982 No Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan A.Ye. Kunduzbayeva 7900319475328460019983 7900319475328460019983 No Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan A.M.  Kabdyrakova 7900319475328460019984 7900319475328460019984 No Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan A.R.  Ivanova 7900319475328460019985 7900319475328460019985 No Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan А.O.  Aidarkhanov 7900319475328460019986 7900319475328460019986 No Branch «Institute of Radiation Safety and Ecology» of the Republican State Enterprise «National Nuclear Center of the Republic of Kazakhstan», Kurchatov, Kazakhstan