Radiation biology. Radioecology
ISSN: 0869-8031

Archives → 2020 → V. 60. №6. → pp. 647-660

Article

Thorium Concentrations in the Environment: A Review of the World Data S.

S. V. Fesenkoa and E. S. Emlutinaa

Russian Research Institute of Radiology and Agroecology, Obninsk, Russia

Abstract

A review of the world data on the thorium activity concentrations in soils, the atmosphere, surface waters, and bottom sediments is presented. It was shown that 232Th concentrations in the soil of regions with a normal radiation background vary from 5 to 95 Bq/kg, in the aquatic environment from 0.01 to 10.0 mBq/l, in bottom sediments of surface waters from 4 to 100 Bq/kg, and groundwater from 0.6 × 10–7 Bq/l to 1.0 × 10–4 Bq/l, and in the atmosphere from 0.1 to 1 × 10–4 Bq/m3. In areas with elevated radiation background and area of thorium mining, in regions of the rare earth elements, or tin, the concentration of thorium in environment can be from one to four orders of magnitude higher than those in areas of normal background radiation. It is also demonstrated that the use of data on the violation of the isotopic equilibrium of thorium content in various media can be used to assess the pathways of thorium release into the environment. It is noted that the spatial patterns of thorium concentrations in soil and bottom sediments are quite close and differ from the patterns of thorium distribution in surface waters.

Keywords

thorium, uranium, natural environments, data review, soil, surface water, bottom sediments, atmosphere