Document Detail

Thoron and decay products, beyond UNSCEAR 2006 Annex E.
MedLine Citation:
PMID:  20966204     Owner:  NLM     Status:  MEDLINE    
Uranium and thorium series radionuclides are present in all soils and rocks. Thus, radon and thoron, the radioactive noble gases originating in the uranium ((238)U) and thorium ((232)Th) decay chains is ubiquitous and everyone is exposed to both radon and thoron gases and their particulate radioactive decay products. As described in UNSCEAR Annex E (2006), radon and its decay products have been recognised for many years as a hazard to underground miners. More recently, the risks from exposure to residential radon have been demonstrated through residential case-control epidemiological studies. However, as discussed by UNSCEAR, exposures to thoron and its decay products have often been relatively ignored. Moreover, unlike radon the effects of exposure to thoron and its decay products are not available from epidemiology and thus, a dosimetric approach is required to assess risks. UNSCEAR continues to recommend the use of a dose conversion factor for thoron decay products of 40 nSv (Bq h m(-3))(-1). UNSCEAR Annex E suggests there is an emerging problem, namely, that the contribution of (220)Rn (thoron) gas to the (222)Rn (radon) gas measurement signal is not well known. Until recently, this has largely been ignored. This is an important consideration as measurements at work and homes are the basis for investigating lung cancer exposure-response relationships. Based on UNSCEAR Annex E, this paper provides an overview of the sources and levels of thoron and its associated decay products at home and work. In addition, this paper provides an overview of the thoron dosimetry considered by UNSCEAR Annex E and some recent results.
D B Chambers
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Radiation protection dosimetry     Volume:  141     ISSN:  1742-3406     ISO Abbreviation:  Radiat Prot Dosimetry     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-10-22     Completed Date:  2011-03-07     Revised Date:  2011-05-23    
Medline Journal Info:
Nlm Unique ID:  8109958     Medline TA:  Radiat Prot Dosimetry     Country:  England    
Other Details:
Languages:  eng     Pagination:  351-6     Citation Subset:  IM    
SENES Consultants Limited, Unit 12, Richmond Hill, ON, Canada.
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MeSH Terms
Air Pollutants
Air Pollutants, Radioactive
Air Pollution, Indoor / analysis*
Environmental Exposure
International Cooperation
Lung Neoplasms / etiology,  prevention & control
Neoplasms, Radiation-Induced / prevention & control
Occupational Exposure
Radiation Monitoring / standards*
Radon / analysis*
Radon Daughters / analysis*
United Nations
Reg. No./Substance:
0/Air Pollutants; 0/Air Pollutants, Radioactive; 0/Radon Daughters; 10043-92-2/Radon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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