Author contribution: Zozul YuN — preparation and analysis of research data; Kiselev SМ, Laschenova ТN — overall management, analysis of research data; Shlygin VV — assessment of radiological situation, data processing; Akhromeev SV — spectrometry, data acquisition; Gimadova TI — thermoluminescence dosimetry; Malakhova AN — data acquisition, working with TL-dosimeters; Shashkova OB — atomic absorption spectrometry; Oskina KYu — radiochemistry research.

Compliance with ethical standards: the study was carried out in full compliance with radiation safety measures and labour protection requirements. No research involving himan subjects or animals was performed.