Simple download service (Atom) of the dataset: Classification of municipalities for risk RADON in the department of Nièvre (58)

Radon is a radioactive gas produced by the natural decay of uranium present in rocks. Pulmonary carcinogen, it can pose a health risk when it accumulates in buildings. Knowledge of the characteristics of geological formations in the territory makes it possible to identify areas where radon at high concentrations in buildings is most likely. This work, carried out by the IRSN at the request of the Nuclear Safety Authority, has made it possible to map the radon potential covering the entire metropolitan area. This mapping leads to the classification of municipalities into 3 categories: Category 1 Category 1 radon-potential municipalities are those located on geological formations with the lowest uranium content. These formations correspond in particular to the limestone, sandy and clay formations of the large sedimentary basins (Paris Basin, Aquitaine basin) and basaltic volcanic formations (central Massif, French Polynesia, West Indies, etc.). On these formations, the vast majority of buildings have low radon concentrations. The results of the national measurement campaign in metropolitan France show that only 20 % of buildings exceed 100 Bq.m-3 and less than 2 % exceed 400 Bq.m-3. Category 2 Category 2 radon-potential municipalities are those located on geological formations with low uranium content but where particular geological factors may facilitate the transfer of radon to buildings. The municipalities concerned are particularly those intersected by major faults or where underground mining works are located in the basement... These particular geological conditions can locally facilitate the transport of radon from the rock to the soil surface and thus increase the likelihood of high concentrations in buildings. Category 3 Category 3 radon-potential municipalities are those with at least part of their area with geological formations with an estimated higher uranium content compared to other formations. The formations concerned include granitic massifs (Armoric Massif, Central Massif, French Guiana, etc.), certain volcanic formations (Central Massif, French Polynesia, Mayotte...) but also some black sands and shale. Of these uranium-rich formations, the proportion of buildings with high radon concentrations is higher than in the rest of the territory. The results of the national measurement campaign in metropolitan France show that more than 40 % of the buildings on these grounds exceed 100 Bq.m-3 and more than 6 % exceed 400 Bq.m-3.