An approach to define potential radon emission level maps using indoor radon concentration measurements and radiogeochemical data positive proportion relationships

• Published in: Journal of environmental radioactivity Vol. 124; pp. 57 - 67
• Main Authors: Drolet, Jean-Philippe, Martel, Richard, Poulin, Patrick, Dessau, Jean-Claude, Lavoie, Denis, Parent, Michel, Lévesque, Benoît
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2013; Elsevier
• Subjects: Air Pollutants, Radioactive - analysis; Air Pollution, Indoor - analysis; Airborne survey; analysis of variance; ANOVA; Applied sciences; Atmospheric pollution; bedrock; Biological and medical sciences; Biological effects of radiation; Buildings. Public works; clay; Criteria; Data Collection; Emission; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; gamma radiation; Geographic Mapping; Geologic Sediments; Geology; Heterogeneity; Housing; Indoor; Indoor pollution and occupational exposure; permeability; Pollution; Pollution indoor buildings; Quebec; Radiation Monitoring; Radioactivity; Radiocontamination; Radon; Radon - analysis; Radon mapping; risk; Sediment; silt; surveys; Tissues, organs and organisms biophysics; Uranium; Uranium - analysis; Quebec; Canada; North America; America; Canada, Quebec; Uranium; Sediment; Geology; ANOVA; Radon mapping; Airborne survey; Natural origin pollution; Cartography; Radioactive pollution; Radon; Radioactive contamination; Radioisotope; Housing; Radioactivity measurement; Health and environment; Risk assessment; Indoor pollution; Aerial survey; Public health
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/j.jenvrad.2013.04.006

The aim of this paper is to present the first step of a new approach to make a map of radonprone areas showing different potential radon emission levels in the Quebec province. This map is a tool intended to assist the Quebec government in identifying populations with a higher risk of indoor radon gas exposure. This map of radon-prone areas used available radiogeochemical information for the province of Quebec: (1) Equivalent uranium (eU) concentration from airborne surface gamma-ray surveys; (2) uranium concentration measurements in sediments; and (3) bedrock and surficial geology. Positive proportion relationships (PPR) between each individual criterion and the 1417 available basement radon concentrations were demonstrated. It was also shown that those criteria were reliable indicators of radon-prone areas. The three criteria were discretized into 3, 2 and 2 statistically significant different classes respectively. For each class, statistical heterogeneity was validated by Kruskal–Wallis one way analyses of variance on ranks. Maps of radon-prone areas were traced down for each criterion.
Based on this statistical study and on the maps of radon-prone areas in Quebec, 18% of the dwellings located in areas with an equivalent uranium (eU) concentration from airborne surface gamma-ray surveys under 0.75 ppm showed indoor radon concentrations above 150 Bq/m3. This percentage increases to 33% when eU concentrations are between 0.75 ppm and 1.25 ppm and exceeds 40% when eU concentrations are above 1.25 ppm. A uranium concentration in sediments above 20 ppm showed an indoor radon concentration geometric mean of 215 Bq/m3 with more than 69% of the dwellings exceeding 150 Bq/m3 or more than 50% of dwellings exceeding the Canadian radon guideline of 200 Bq/m3. It is also shown that the radon emission potential is higher where a uranium-rich bedrock unit is not covered by a low permeability (silt/clay) surficial deposit.
•5 criteria were identified in international studies to map radon-prone areas.•PPR between each criterion and indoor radon concentrations was validated.•For each criterion, statistically similar classes were merged.•Each discretized criterion was mapped into two or three heterogeneous classes.•Merged classes were related to different potential radon emission levels.