234U/238U disequilibrium and 235U/238U ratios measured using MC-ICP-MS in natural high background radiation area soils to understand the fate of uranium

Nimelan Veerasamy; Sharayu Kasar; Rajamanickam Murugan; Kazumasa Inoue; Thennaarassan Natarajan; Rakesh Chand Ramola; Masahiro Fukushi; Sarata Kumar Sahoo

doi:10.1016/j.chemosphere.2023.138217

²³⁴U/²³⁸U disequilibrium and ²³⁵U/²³⁸U ratios measured using MC-ICP-MS in natural high background radiation area soils to understand the fate of uranium

Chemosphere. 2023 May:323:138217. doi: 10.1016/j.chemosphere.2023.138217. Epub 2023 Feb 25.

Authors

Nimelan Veerasamy¹, Sharayu Kasar², Rajamanickam Murugan², Kazumasa Inoue³, Thennaarassan Natarajan¹, Rakesh Chand Ramola⁴, Masahiro Fukushi³, Sarata Kumar Sahoo⁵

Affiliations

¹ Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan; National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
² National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
³ Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo, 116-8551, Japan.
⁴ H.N.B. Garhwal University, Badshahi Thaul Campus, Tehri Garhwal, 249 199, India.
⁵ National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan. Electronic address: sahoo.sarata@qst.go.jp.

PMID: 36849023
DOI: 10.1016/j.chemosphere.2023.138217

Abstract

The Chhatrapur-Gopalpur coastal area in Odisha, India is a well-known natural high background radiation (HBRA) area due to the abundance of monazite (a thorium bearing radioactive mineral) in beach sands and soils. Recent studies on Chhatrapur-Gopalpur HBRA groundwater have reported high concentrations of uranium and its decay products. Therefore, the soils of the Chhatrapur-Gopalpur HBRA are reasonably suspected as the sources of these high uranium concentrations in groundwater. In this report, first the uranium concentrations in soil samples were measured using inductively coupled plasma mass spectrometry (ICP-MS) and they were found to range from 0.61 ± 0.01 to 38.59 ± 0.16 mg kg^-１. Next, the ²³⁴U/²³⁸U and ²³⁵U/²³⁸U isotope ratios were measured to establish a baseline for the first time in Chhatrapur-Gopalpur HBRA soil. Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) was used for measurement of these isotope ratios. The ²³⁵U/²³⁸U ratio was observed to be the normal terrestrial value. The ²³⁴U/²³⁸U activity ratio, was calculated to understand the secular equilibrium between ²³⁴U and ²³⁸U in soil and it varied from 0.959 to 1.070. To understand the dynamics of uranium in HBRA soil, physico-chemical characteristics of soil were correlated with uranium isotope ratios and this correlation of ²³⁴U/²³⁸U activity ratio indicated the leaching of ²³⁴U from Odisha HBRA soil.

Keywords: (234)U/(238)U; (235)U/(238)U; HBRA; MC-ICP-MS; Monazites; Uranium.

MeSH terms

Background Radiation
Isotopes / analysis
Soil
Soil Pollutants, Radioactive* / analysis
Uranium* / analysis

Substances

Soil
Uranium
Soil Pollutants, Radioactive
Isotopes