Radiation situation in the territories affected by mining activities in Stepnogorsk areas, Republic of Kazakhstan: pilot study

The Republic of Kazakhstan has a long history of mining activities, viz., gold and uranium. Mining activities represent sources of potential naturally occurring radionuclides contamination of the environment and human health of population. The aim of this study was to investigate the radiation situation of industrially modified environment in Stepnogorsk areas of Kazakhstan to understand the sources of contamination. Quite high values of ambient equivalent dose rates in air ∼2.87 μSv h^-1 were found in the Aqsu gold-mining site. The radon equivalent equilibrium volume activity (indoor) were in the range of 313-858 Bq m^-3 in the study area buildings. The high values of activity concentration of natural radionuclides found in Aqsu soil samples were ²²⁶Ra-4060, ²³²Th-1170 and ⁴⁰K-4080 Bq kg^-1, respectively. However, our comprehensive surveys implied that the increased natural radiation background caused by the radionuclide transport from the tailing area did not have an impact, while evaluation of its potential radiation risks and remediation of the territories of the former gold mining should be needed. (authors)