National Radon Survey in Argentina. Annex I

In 1983, Argentina's Autoridad Regulatoria Nuclear (ARN) initiated a national radon survey, which was carried out on a phased basis over several years, until 2011. The main reason for undertaking the survey was to identify areas of the country with elevated radon concentrations. In the 1980s, a clear relationship between residential exposure due to radon and lung cancer risk had not yet been demonstrated. Higher concentrations of radon were found in connection with some cases of occupational exposure, so it was important from the point of view of radiation protection to know whether there were areas of the country with elevated radon concentrations. A second objective was later added: to assess the average radiation dose and the range of radiation doses received by the Argentine population due to radon, for comparison with doses due to other sources of radiation, as radon is the main natural source for radiation exposure of the public. As for areas of potentially elevated radon concentrations indoors, Argentina has a number of locations where uranium was previously mined, which raises the likelihood of radon being present. Uranium was mined mainly by means of open pit technology and a lixiviation (leaching or dissolving) process, and at a few locations by underground mining. The mineral was present in low grade deposits. All uranium mining activities ended in 1997 and the majority of the uranium mines are closed. One uranium mining facility could potentially be reopened, but it is not currently operating. All of these old mine areas are controlled through regulation and monitoring by the ARN. As described above, the initial objective of the residential radon survey was to identify areas of the country with elevated radon concentrations. However, the project was later oriented with the regulatory objective of assessing the exposure of members of the public whose dwellings are in the surroundings of the uranium mining facilities, as radon gas is the main radiological hazard associated with these sites. Argentina has adopted an annual average radon concentration of 400 Bq/m³ as the national reference level above which corrective actions to reduce radon concentrations in dwellings are to be considered. ARN is in the process of revising its standards, and as part of this effort, the national reference level for radon will be revised and IAEA recommendations will be taken into account.