Radionuclide activity in soil samples at a site from Atomic Lake to the neighbor winter camps of Sarapan and Zhanan at the boundary of the southeast part of Semipalatinsk test site

Abstract In this investigation we studied the content of some extremely dangerous radionuclides (¹³⁷Cs, ⁹⁰Sr, ²⁴¹Am, ²³⁹⁺²⁴⁰Pu) in soil samples taken around "Atomic lake" moving from the explosion crater by 4 terrains. Selected sampling terrains pass through the wintering grounds of Sarapan and Zhanan located at the south-east part of the former Semipalatinsk test site (STS). The research results have shown that soil samples near "Atomic lake" have a wide range of radionuclide activity values: ¹³⁷Cs from 6.8 to 4500 Bq/kg, ⁹⁰Sr from < 8 to 4300 Bq/kg, ²⁴¹Am from 1 to 350 Bq/kg, ²³⁹⁺²⁴⁰Pu from 7 to 1800 Bq/kg. The highest radioactivity levels are found in soil samples near "Atomic lake". The content of ²⁴¹Am is within the admissible limit values, whereas the content of ¹³⁷Cs and ²³⁹⁺²⁴⁰Pu exceeds the regulated values at some sampling places. The coefficient of variation of radionuclides content in studied soils has high values: ¹³⁷Cs (240%), ⁹⁰Sr (193%), ²⁴¹Am (225%), and ²³⁹ ⁺ ²⁴⁰Pu (225%). This fact shows a high degree of the results scatter, which is most likely associated with a high activity of soils near "Atomic Lake".