Assessing tritium contamination in Thailand's rainwater: A study of environmental monitoring and nuclear surveillance

Kanokwan Khamanek; Soontree Khuntong; Kiadtisak Saenboonruang; Donruedee Toyen; Chittranuch Chantarot; Monthon Yongprawat; Chakrit Saengkorakot; Archara Phattanasub; Piyawan Krisanangkura; Ryuta Hazama; Anawat Rittirong; Wanwisa Sudprasert

doi:10.1016/j.jenvrad.2023.107151

Assessing tritium contamination in Thailand's rainwater: A study of environmental monitoring and nuclear surveillance

J Environ Radioact. 2023 Jun:262:107151. doi: 10.1016/j.jenvrad.2023.107151. Epub 2023 Mar 11.

Affiliations

¹ Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
² Faculty of Science at Sriracha, Kasetsart University, Sriracha, Cholburi, 20230, Thailand.
³ Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
⁴ Nuclear Technology Research and Development Center, Thailand Institute of Nuclear Technology (Public Organization), Nakhon Nayok, 26120, Thailand.
⁵ Radioactive Waste Management Center, Thailand Institute of Nuclear Technology (Public Organization), Nakhon Nayok, 26120, Thailand.
⁶ Office of Atoms for Peace, Bangkok, 10900, Thailand.
⁷ Graduate School of Human Environment, Osaka Sangyo University, Osaka, 574-8530, Japan.
⁸ Research Center for Nuclear Physics, Osaka University, Osaka, 574-8530, Japan.
⁹ Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. Electronic address: fsciwasu@ku.ac.th.

PMID: 36913797
DOI: 10.1016/j.jenvrad.2023.107151

Abstract

Tritium, whether naturally occurring or caused by human nuclear activity, can result in a large amount of tritium contamination in the environment, especially in the water cycle, causing a high concentration of tritium in rainfall. The objective of this research was to measure the level of tritium in the environment from rainfall in two different areas as a basis for monitoring tritium contamination in the environment. Rainwater samples were collected in Thailand every 24 h for a period of 1 year during 2021-2022 at the Kasetsart University Station, Sriracha Campus, Chonburi province and at the Mae Hia Agricultural Meteorological Station, Chiang Mai province. The tritium levels were measured in rainwater samples using the electrolytic enrichment method combined with liquid scintillation counting. The chemical composition of the rainwater was analyzed based on ion chromatography. The results (presented with ± combined uncertainty) showed that the tritium content in the rainwater samples at Kasetsart University Station Sriracha Campus was in the range 0.9 ± 0.2-1.6 ± 0.3 TU (0.11 ± 0.02-0.19 ± 0.03 Bq.L^-1). The mean concentration was 1.0 ± 0.2 TU (0.12 ± 0.03 Bq.L^-1). The most common ions found in the rainwater samples were SO₄^2-, Ca²⁺, and NO₃^-, with mean concentrations of 1.52 ± 0.82, 1.08 ± 0.51, and 1.05 ± 0.78 mg.L^-1, respectively. The tritium content in rainwater collected from the Mae Hia Agricultural Meteorological Station was in the range 1.6 ± 0.2-4.9 ± 0.4 TU (0.19 ± 0.02-0.58 ± 0.05 Bq.L^-1). The mean concentration was 2.4 ± 0.4 TU (0.28 ± 0.05 Bq.L^-1). The most common ions found in the rainwater were NO₃^-, Ca²⁺, and SO₄^2-, with mean concentrations of 1.21 ± 1.02, 0.67 ± 0.43, and 0.54 ± 0.41 mg.L^-1, respectively. The tritium concentration in the rainwater at both stations differed but remained at a natural level (less than 10 TU). There was no correlation between the tritium concentration and the chemical composition of the rainwater. The tritium levels obtained from this study could be used as a basis for reference and monitoring of future environmental changes due to nuclear accidents or activities, both domestically and internationally.

Keywords: Liquid scintillation counter (LSC); Nuclear activities; Precipitation; Rainwater; Tritium.

MeSH terms

Environmental Monitoring
Humans
Radiation Monitoring*
Rain
Thailand
Tritium / analysis
Water Pollutants, Radioactive* / analysis

Substances

Tritium
Water Pollutants, Radioactive