Cold season dose rate contributions from gamma, radon, thoron or progeny in legacy mines with high natural background radiation.
Journal
Radiation protection dosimetry
ISSN: 1742-3406
Titre abrégé: Radiat Prot Dosimetry
Pays: England
ID NLM: 8109958
Informations de publication
Date de publication:
21 Jul 2023
21 Jul 2023
Historique:
received:
01
11
2022
revised:
12
05
2023
accepted:
16
05
2023
medline:
24
7
2023
pubmed:
20
6
2023
entrez:
20
6
2023
Statut:
ppublish
Résumé
In areas with high natural background radiation, underground cavities tend to have high levels of airborne radionuclides. Within mines, occupancy may involve significant exposure to airborne radionuclides like radon (222Rn), thoron (220Rn) and progeny. The Fen carbonatite complex in Norway has legacy mines going through bedrock with significantly elevated levels of uranium (238U) and especially thorium (232Th), and significant levels of their progeny 222Rn and 220Rn. There are also significantly elevated levels of gamma radiation in these mines. These mines are naturally chimney ventilated and release large volumes of air to the outdoors giving a large local outdoor impact. We placed alpha track detectors at several localities within these mines to measure airborne radionuclides and measured gamma radiation of bedrock at each locality. The bedrock within the mines shows levels up to 1900 Bq kg-1 for 238U, 12 000 Bq kg-1 for 232Th and gamma dose rates up to 11 μSv h-1. Maximum levels of airborne radionuclides were 45 000 Bq m-3 for 220Rn and 6900 Bq m-3 for 222Rn. In addition, we measured levels of thoron progeny (TnP). In order to estimate radiation dose contribution, TnP should be assessed rather than 220Rn, but deposition-based detectors may be biased by the airflow of mine-draft. We present dose rate contributions using UNSCEAR dose conversion factors, and correcting for airflow bias, finding a combined cold season dose rate within these mines of 17-24 μSv h-1. Interestingly, fractional dose rate contributions vary from 0.02 to 0.6 for gamma, 0.33 to 0.95 for radon and 0.1 to 0.25 for TnP.
Identifiants
pubmed: 37337628
pii: 7202086
doi: 10.1093/rpd/ncad178
pmc: PMC10361218
doi:
Substances chimiques
Radon-222
0
Radon-220
0
Radon
Q74S4N8N1G
Thorium-232
0
Thorium
60YU5MIG9W
Uranium-238
0
Uranium
4OC371KSTK
Air Pollutants, Radioactive
0
Radon Daughters
0
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
1284-1294Subventions
Organisme : RadoNorm project
Organisme : Research Council of Norway
ID : 900009
Organisme : Centre for Environmental Radioactivity
Organisme : Norwegian Meteorological Institute
Informations de copyright
© The Author(s) 2023. Published by Oxford University Press.
Références
J Environ Radioact. 2016 Oct;162-163:23-32
pubmed: 27214284
Radiat Prot Dosimetry. 2012 Nov;152(1-3):18-24
pubmed: 22929556
Ann ICRP. 1993;23(2):1-45
pubmed: 8179237
J Environ Radioact. 2004;71(1):17-32
pubmed: 14557034
J Environ Radioact. 2011 Sep;102(9):806-12
pubmed: 21703736
Am J Public Health. 1995 Apr;85(4):535-40
pubmed: 7702118
Health Phys. 1976 Aug;31(2):139-45
pubmed: 972046
Radiat Prot Dosimetry. 2010 Oct;141(4):424-7
pubmed: 20829202
J Radiat Res. 2013 Jul 1;54(4):597-610
pubmed: 23297318
Health Phys. 2018 Oct;115(4):500-506
pubmed: 30148815
Indoor Air. 2011 Jun;21(3):240-52
pubmed: 21198887
Health Phys. 1985 Apr;48(4):415-20
pubmed: 2984147
Ann ICRP. 2017 Dec;46(3-4):1-486
pubmed: 29380630
Radiat Prot Dosimetry. 2020 Jul 17;189(3):401-405
pubmed: 32367128
J Environ Radioact. 2015 Oct;148:67-73
pubmed: 26117280
Health Phys. 2018 Oct;115(4):490-499
pubmed: 30148814
J Environ Radioact. 2002;60(3):263-74
pubmed: 12054040