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Canadian Journal of Public Health

, Volume 104, Issue 3, pp e240–e245 | Cite as

A Comparison of Two Methods for Ecologic Classification of Radon Exposure in British Columbia: Residential Observations and the Radon Potential Map of Canada

  • Stephen A. Rauch
  • Sarah B. HendersonEmail author
Quantitative Research
  • 1 Downloads

Abstract

Objective

To compare ecologic classification of radon exposure from observed residential concentrations in BC with classifications based on a map that shows geological radon potential, with particular attention to high-smoking populations.

Methods

First, residential radon measurements from four health agencies were used to classify 74 local health areas (LHAs) as low, moderate, or high exposure based on the number of homes with concentrations greater than 200 and 600 Bq/m3. Second, the Zone 1 (high), Zone 2 (elevated), and Zone 3 (guarded) risk categories of the radon potential map of Canada were used to make the same exposure classifications based on the populationweighted area of each zone in each LHA. Agreement was compared and quantified. Average smoking rates in each LHA were used to further assess agreement for smokers, who are a high-risk group.

Results

Both methods showed a range of exposure across LHAs. The radon potential map classified more areas as high exposure than the observed radon concentrations, and the methods agreed in 30 of 74 LHAs. The radon potential map identified much of the southern coastal region as high exposure, but 617 of the 621 observed concentrations were ≤200 Bq/m3, and no observations were >600 Bq/m3. An estimated 36% of the BC population and 35% of BC smokers live in the southern coastal region.

Conclusions

The radon potential map of Canada may communicate potential radon risk, but it was not designed for epidemiologic exposure assessment. Overall, the potential map classified 34 LHAs as higher than observed, and 10 LHAs as lower than observed. The potential map should only be used to inform exposure assessment in conjunction with observed radon concentrations.

Key Words

Radon environmental exposure epidemiologic methods geographic information systems risk assessment 

Résumé

Objectifs

Comparer la classification écologique de l’exposition au radon selon 1) les concentrations dans les habitations observées en Colombie-Britannique et 2) les classifications basées sur une carte montrant le potentiel géologique d’exhalation de radon, en accordant une attention particulière aux populations où le tabagisme est élevé.

Méthode

Premièrement, nous avons utilisé les mesures du radon dans les habitations provenant de quatre organismes de santé pour classer 74 circonscriptions sanitaires (CS) selon leur niveau d’exposition (faible, modéré ou élevé) d’après le nombre d’habitations ayant des concentrations supérieures à 200 et à 600 Bq/m3. Deuxièmement, les catégories de risque selon la carte du potentiel en radon du Canada (Zone 1 [niveau le plus élevé], Zone 2 [niveau élevé] et Zone 3 [prudence]) ont servi à établir les mêmes classifications de l’exposition d’après la superficie pondérée de chaque zone, dans chaque CS. Les données concordantes ont été comparées et chiffrées. Ensuite, les taux de tabagisme moyens dans chaque CS ont servi à évaluer la concordance des données pour les fumeurs, qui constituent un groupe à risque élevé.

Résultats

Les deux méthodes montrent divers niveaux d’exposition d’une CS à l’autre. La carte du potentiel en radon classe davantage de zones dans la catégorie de niveau le plus élevé que les concentrations observées, et les deux méthodes concordent pour 30 des 74 CS. Selon la carte du potentiel en radon, une grande partie de la région côtière sud affiche le niveau d’exposition le plus élevé, mais 617 des 621 concentrations observées sont 200 Bq/m3, et l’on n’a observé aucune concentration >600 Bq/m3. Selon les estimations, 36 % de la population britanno-colombienne et 35 % des fumeurs de la Colombie-Britannique vivent dans la région côtière sud.

Conclusions

La carte du potentiel en radon du Canada peut communiquer le potentiel d’exposition au radon, mais elle n’est pas conçue pour l’évaluation du risque épidémiologique. Globalement, la carte du potentiel classe 34 CS dans une catégorie supérieure au niveau observé et 10 CS dans une catégorie inférieure au niveau observé. Cette carte ne devrait donc être utilisée que pour éclairer l’évaluation de l’exposition, conjointement avec les concentrations en radon observées.

Mots Clés

radon exposition environnementale méthodes épidémiologiques systèmes d’information géographique évaluation du risque 

References

  1. 1.
    Committee on Health Risks of Exposure to Radon. Health Effects of Exposure to Radon: BEIR VI. Washington, DC: The National Academies Press, 1999.Google Scholar
  2. 2.
    Darby S, Hill D, Auvinen A, Barros-Dios JM, Baysson H, Bochicchio F, et al. Radon in homes and risk of lung cancer: Collaborative analysis of individual data from 13 European case-control studies. BMJ 2005;330(7485):223.CrossRefGoogle Scholar
  3. 3.
    Krewski D, Lubin JH, Zielinski JM, Alavanja M, Catalan VS, Field RW, et al. Residential radon and risk of lung cancer: A combined analysis of 7 North American case-control studies. Epidemiol 2005;16(2):137–45.CrossRefGoogle Scholar
  4. 4.
    Zhang ZL, Sun J, Dong JY, Tian HL, Xue L, Qin LQ, et al. Residential radon and lung cancer risk: An updated meta-analysis of case-control studies. Asian Pacific J Cancer Prev 2012;13(6):2459–65.CrossRefGoogle Scholar
  5. 5.
    Saccomanno G, Huth GC, Auerbach O, Kuschner M. Relationship of radioactive radon daughters and cigarette smoking in the genesis of lung cancer in uranium miners. Cancer 1988;62(7):1402–8.CrossRefGoogle Scholar
  6. 6.
    Chen J, Moir D, Whyte J. Canadian population risk of radon induced lung cancer: A reassessment based on the recent cross-Canada radon survey. Radiat Prot Dosimetry 2012;152(1-3):9–13.CrossRefGoogle Scholar
  7. 7.
    Létourneau EG, Krewski D, Choi NW, Goddard MJ, McGregor RG, Zielinski JM, et al. Case-control study of residential radon and lung cancer in Winnipeg, Manitoba, Canada. Am J Epidemiol 1994;140(4):310–22.CrossRefGoogle Scholar
  8. 8.
    Stidley CA, Samet JM. A review of ecologic studies of lung cancer and indoor radon. Health Physics 1993;65(3):234–51.CrossRefGoogle Scholar
  9. 9.
    Evrard AS, Hémon D, Billon S, Laurier D, Jougla E, Tirmarche M, et al. Ecological association between indoor radon concentration and childhood leukaemia incidence in France, 1990–1998. Eur J Cancer Prev 2005;14(2): 147–57.CrossRefGoogle Scholar
  10. 10.
    Wheeler BW, Allen J, Depledge MH, Curnow A. Radon and skin cancer in Southwest England: An ecologic study. Epidemiol 2012;23(1):447–52.CrossRefGoogle Scholar
  11. 11.
    Savitz DA. Commentary: A niche for ecologic studies in environmental epidemiology. Epidemiol 2012;23(1):53–54.CrossRefGoogle Scholar
  12. 12.
    Henderson S, Kosatsky T, Barn P. How to ensure that national radon survey results are useful for public health practice. Can J Public Health 2012;103(3):231–34.PubMedGoogle Scholar
  13. 13.
    Radon Environmental Management Corp. Radon Potential Map of Canada. 2011. Available at: https://doi.org/www.radoncorp.com/pdf/presentationMapping-Public.pdf (Accessed November 1, 2012).Google Scholar
  14. 14.
    Health Canada. Cross-Canada Survey of Radon Concentrations in Homes: Final Report. Ottawa, ON: 2012;29.Google Scholar
  15. 15.
    Health Canada. Government of Canada Radon Guideline, 2012. Available at: https://doi.org/www.hc-sc.gc.ca/ewh-semt/radiation/radon/guidelines_lignes_directrice-eng.php (Accessed November 15, 2012).Google Scholar
  16. 16.
    BC Stats. Population Extrapolation for Organizational Planning with Less Error (P.E.O.P.L.E.). 2012. Available at: https://doi.org/www.bcstats.gov.bc.ca/StatisticsBySubject/Demography/PopulationEstimates.aspx (Accessed August 30, 2012).Google Scholar
  17. 17.
    Canadian Community Health Survey (CCHS): Annual Component User Guide for the 2008 Microdata Files. 2009;95.Google Scholar
  18. 18.
    Canadian Community Health Survey (CCHS): Supplement to the User Guide for the British Columbia Sample Buy-in. 2011;4.Google Scholar
  19. 19.
    R Development Core Team. R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing, 2009.Google Scholar
  20. 20.
    Hunter N, Muirhead CR, Miles JCH, Appleton JD. Uncertainties in radon related to house-specific factors and proximity to geological boundaries in England. Radiat Prot Dosimetry 2009;136(1):17–22.CrossRefGoogle Scholar
  21. 21.
    Bertolo A, Verdi L. Validation of a geographic information system for the evaluation of the soil radon exhalation potential in South-Tyrol and Veneto (Italy). Radiat Prot Dosimetry 2001;97(4):321–24.CrossRefGoogle Scholar
  22. 22.
    Appleton JD, Miles JCH, Young M. Comparison of Northern Ireland radon maps based on indoor radon measurements and geology with maps derived by predictive modelling of airborne radiometric and ground permeability data. Sci Total Environ 2011;409(8):1572–83.CrossRefGoogle Scholar
  23. 23.
    Canivez GL. Validity and diagnostic efficiency of the Kaufman Brief Intelligence Test in reevaluating students with learning disability. J Psychoeducational Assessment 1996;14(1):4–19.CrossRefGoogle Scholar

Copyright information

© The Canadian Public Health Association 2013

Authors and Affiliations

  1. 1.British Columbia Centre for Disease ControlVancouverCanada

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