“Hot” and active particles in alluvial soils and sediments of the Yenisei river: Radioisotope composition

Institute of Geology and Mineralogy SB RAS, 630090 Novosibirsk, Russia

Abstract

New data on abundance and isotope composition of “hot” and active particles in alluvial soils and sediments of the Yenisei river (Krasnoyarsk region, Russia), located in a near influence zone of the Krasnoyarsk Mining and Chemical Processing Plant (KMCPP), are presented in this study. On a set of gamma-emitting radioisotopes all “hot” particles can be divided on three groups: 1. monoisotopic (¹³⁷Cs, ⁶⁰Co); 2. two-isotopic (¹³⁷Cs and ¹³⁴Cs); 3. polyisotopic (¹³⁷Cs, ¹³⁴Cs, ⁶⁰Co, ¹⁵⁴Eu, ¹⁵⁵Eu and ²⁴¹Am). Very significant is the absence of ¹⁵²Eu in all polyisotopic particles whereas in soils this isotope is often predominant. The active particles are presented by the several polyisotopic types, containing: 1. ¹⁵⁴Eu, ¹⁵⁵Eu, ¹³⁷Cs, ⁶⁰Co and ²⁴¹Am; 2. ¹⁵⁴Eu, ¹⁵⁵Eu, ¹³⁷Cs and ²⁴¹Am; 3. ¹⁵²Eu, ¹⁵⁴Eu, ¹⁵⁵Eu, ⁶⁰Co and ²⁴¹Am and monoisotopic (⁶⁰Co and ¹³⁷Cs). Presence of the active particles containing all isotopes, except of ¹³⁷Cs, and particles without ¹⁵²Eu and ⁶⁰Co is interesting. Some active particles due to their set of radioisotopes can be referred to the finely dispersed fragments of the “hot” particles. However, the majority of them have the nature distinct from the “hot” particles.