Indoor and outdoor 222Rn and 220Rn and their progeny levels surrounding Bayan Obo mine, China

Wang, Nanping; Hu, Miao; Zeng, Weihua; Yu, Cong; Jia, Binlin; Yang, Zhijie

doi:10.2478/nuka-2020-0023

Abstract

More than half of the total natural ionizing radiation dose received by the human population is caused by radon and thoron (Rn and Tn) and their progeny. To estimate the level of radiation due to radon and thoron and their progeny, an investigation was conducted in a residential area near the world’s largest open-pit mine of Bayan Obo in Inner Mongolia, China. The concentration of Rn, Tn, and their decay products in air and soil were studied by using AlphaGUARD, RAD7, and ERS-RDM-2S for a discrete period of time in three different locations. The average indoor concentration of radon and thoron was 62.6 ± 44.6 Bq/m³ and 108.3 ± 94.5 Bq/m3 respectively, and the outdoor concentration was 12.9 ± 6.3 Bq/m³ and 55.8 ± 18.5 Bq/m³, respectively. Relatively high concentrations were recorded in the area near to the mine, with a significant increasing trend observed in indoor thoron concentration. A prominent hotspot in thoron concentration was found in a single-story house with values 747 ± 150 Bq/m³. The equilibrium equivalent thoron concentration (EEC_Tn) varies from 0.48 Bq/m³ to 2.36 Bq/m³ with an arithmetic mean of 1.37 ± 0.64 Bq/m³, and comparatively higher than EEC_Rn. Concluding that the mining activity at Bayan Obo mine is significantly increasing the level of indoor thoron and its progeny in surroundings. It is suggested to further systematically investigate the indoor Rn and Tn progeny concentrations in the residential dwellings of the Bayan Obo mining area, and ²³²Th content of the building materials, to provide a basis for calculating the radiation dose.

References

1. Yang, X., Michael, J., & Le Bas, M. J. (2004). Chemical compositions of carbonate minerals from Bayan Obo, Inner Mongolia, China: implications for petrogenesis. Lithos, 72, 97–116. DOI: 10.1016/j.lithos.2003.09.002.10.1016/j.lithos.2003.09.002
Search in Google Scholar Back to article
2. Wang, X., Guo, C., & Bai, L. (2009). Radiothorium contamination tendency and control measure for Baotou steel factory tailing dam. Radiat. Prot., 29(4), 270–274. DOI: 10.1002/9780470611807.ch2. (in Chinese with English abstract).10.1002/9780470611807.ch2
Search in Google Scholar Back to article
3. Li, R., Li, Q., & Chen, S. (2014). Distribution of radioactive thorium in surrounding soils of Bayan Obo mining area. J. Res. Environ. Sci., 27(1), 51–56. DOI: 10.13198j.issn1001-6929.2014.01.08. (in Chinese with English abstract).
Search in Google Scholar Back to article
4. Li, B., Wang, N., Wan, J., Xiong, S., Liu, H., Li, S., & Zhao, R. (2016). In-situ gamma-ray survey of rare-earth tailings dams–A case study in Baotou and Bayan Obo Districts, China. J. Environ. Radioact., 151(Part 1), 304–310. DOI: 10.1016/j.jenvrad.2015.10.027.10.1016/j.jenvrad.2015.10.02726555365
Search in Google Scholar Back to article
5. Chen, X., & Cheng, Y. (1998). Long-term monitoring of thorium inhaled by workers and assessment of thorium lung burden in China. Radiat. Prot. Dosim., 79, 91–93. DOI: 10.1093/oxfordjournals.rpd.a032475.10.1093/oxfordjournals.rpd.a032475
Search in Google Scholar Back to article
6. Liu, Y., Liu, F., & Wang, C. (2010). Primary measure of equipment factor of ²²²Rn/²²⁰Rn indoor. Atomic Energy Science and Technology, 44(12), 1527–1531. (in Chinese with English abstract).
Search in Google Scholar Back to article
7. Wang, C., Liu, F., & Liu, G. (2015). Influence of Bayan Obo ores on indoor ²²²Rn, ²²⁰Rn and γ radiation levels. Radiat. Prot., 35(5), 305–316.
Search in Google Scholar Back to article
8. De With, G., Smetsers, R. C. G. M., & Slaper, H. (2018). Thoron exposure in Dutch dwellings – An overview. J. Environ. Radioact., 183, 73–81. DOI: 10.1016/j.jenvrad.2017.12.014.10.1016/j.jenvrad.2017.12.01429306710
Search in Google Scholar Back to article
9. Ramachandan, T. V., & Sathish, L. A. (2011). Nationwide indoor ²²²Rn and ²²⁰Rn map for India: a review. J. Environ. Radioact., 102(11), 975–986. DOI: 10.1016/j.jenvrad.2011. 06.009.10.1016/j.jenvrad.2011.06.009
Search in Google Scholar Back to article
10. Vuckovic, B., Gulan, L., & Milenkovic, B. (2016). Indoor radon and thoron concentrations in some towns of central and South Serbia. J. Environ. Radioact., 183(Part 3), 938–944. DOI: 10.1016/j.jenvman.2016.09.053.10.1016/j.jenvman.2016.09.05327681871
Search in Google Scholar Back to article
11. Alharbi, S. H., & Akber, R. A. (2015). Radon and thoron concentrations in public workplaces in Brisbane, Australia. J. Environ. Radioact., 144, 69–76. DOI: 10.1016/j.jenvrad.2015.03.008.10.1016/j.jenvrad.2015.03.00825827573
Search in Google Scholar Back to article
12. Wang, N., Peng, A., & Xiao, L. (2012). The level and distribution of ²²⁰Rn concentration in soil-gas in Guangdong Province, China. Radiat. Prot. Dosim., 152(1/3), 204–209. DOI: 10.1093/rpd/ncs223.10.1093/rpd/ncs22322923249
Search in Google Scholar Back to article
13. He, Z., Xiao, D., & Lv, L. (2017). Controlling ²¹²Bi to ²¹²Pb activity concentration ratio in thoron chambers. J. Environ. Radioact., 178/179, 77–83. DOI: 10.1016/j.jenvrad.2017.07.011.10.1016/j.jenvrad.2017.07.01128797795
Search in Google Scholar Back to article
14. Tracerlab. (2017). ERS-RDM-2S Monitor for the determination of the Radon/Thoron-Gas- & Progeny-concentration. Short-Version-2017/08. Koelm, Germany: Tracerlab GmbH.
Search in Google Scholar Back to article

Indoor and outdoor 222Rn and 220Rn and their progeny levels surrounding Bayan Obo mine, China

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