title: Homogenity of geological units with respect to the radon risk in the Walloon region of Belgium.
abstract: In the process of mapping indoor radon risk, an important step is to define geological units well-correlated with indoor radon. The present paper examines this question for the Walloon region of Belgium, using a database of more than 18,000 indoor radon measurements. With a few exceptions like the Carboniferous (to be divided into Tournaisian, Visean and Namurian-Westphalian) and the Tertiary (in which all Series may be treated together), the Series/Epoch stratigraphic level is found to be the most appropriate geological unit to classify the radon risk. A further division according to the geological massif or region is necessary to define units with a reasonable uniformity of the radon risk. In particular, Paleozoic series from Cambrian to Devonian show strong differences between different massifs. Local hot-spots are also observed in the Brabant massif. Finally, 35 geological units are defined according to their radon risk, 6 of which still present a clear weak homogeneity. In the case of 4 of these units (Jurassic, Middle Devonian of Condroz and of Fagne-Famenne, Ordovician of the Stavelot massif) homogeneity is moderate, but the data are strongly inhomogeneous for Visean in Condroz and in the Brabant massif. The 35 geological units are used in an ANOVA analysis, to evaluate the part of indoor radon variability which can be attributed to geology. The result (15.4-17.7%) agrees with the values observed in the UK.
authors: ISIB, Haute Ecole P.-H. Spaak, Rue Royale 150, 1000 Brussels, Belgium.
authors: François
authors: F
authors: Tondeur
authors: European Commission, DG JRC, Institute for Transuranium Elements, Via E Fermi 2749, I-21027 Ispra, VA, Italy. Electronic address: giorgia.cinelli@jrc.ec.europa.eu.
authors: Giorgia
authors: G
authors: Cinelli
authors: FANC, Ravensteinstraat 36, 1000 Brussels, Belgium.
authors: Boris
authors: B
authors: Dehandschutter
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D001530:Belgium; D062305:Geographic Mapping; D019015:Geologic Sediments / Q000737:chemistry*; D006801:Humans; D011886:Radon / Q000032:analysis*; D018570:Risk Assessment
chemical_list: D000396:Air Pollutants, Radioactive; D011886:Radon
keywords: Geology; Indoor radon; Radon risk; Walloon region of Belgium