The Rad.Ar project: Radon, natural radioactivity and lung carcinogenesis in Argentina

ORIOLO, S.; BELTRÁN, A.; CANTERA, C.; CERETANI, A.; ESTEBAN, F.; FERREYRO, I.; GÓMEZ, A.; KIETZMANN, D.A.; OSTERA, H.; OZAN, I.; RODRIGUEZ, D.; SIVORI, M.S.; TOBAL, J.; VILENSKY, M.; ZACCARA, H.

Congreso; XIII South American Symposium on Isotope Geology; 2024

Radon ( 222 Rn) and its decay products are group 1 carcinogenic agents for lung, being thesecond leading cause of lung cancer after tobacco smoking. 222 Rn is part of the 238 U decay chain and, therefore, radon is commonly higher in areas with uranium concentration. In turn, uranium produces gamma ray radiation, which is also part of the group 1 of carcinogenic agents for lung. In this context, maximum concentration values of indoor radon in air were recommended by different international organisms such as WHO, whereas long-term projects to generate national and international indoor radon maps have been developed. Though indoor radon is associated with uranium content of the soil and bedrock, high indoor concentrations of 222 Rn does not necessarily imply an anomalously high uranium content. However, when uranium deposits occur, high radon flow is also associated with high doses of gamma radiation, a naturally occurring ionizing radiation. Therefore, areas yielding uranium anomalies require a systematic monitoring of both radon flow and gamma radiation exposure, which may have a coupled negative effect in human health. In Argentina, systematic radon measurements are only carried out in nuclear and uranium mining-industrial facilities by the Nuclear Regulatory Authority (ARN). Beyond these areas, only very limited data concerning indoor radon distribution exist, and no epidemiological evaluation of radon and further naturally occurring radioactive materials (NORM) has been so far carried out. ARN data show, in general, concentrations up to ca. 100 Bq/m 3 for indoor radon in different Argentinian cities, though the Gran Mendoza region shows a significant anomaly, with several values higher than ca. 170 Bq/m 3 . Though geologic constraints on the source of radon are so far absent for this area, the presence of significant uranium deposits in the adjacent Precordillera range, located ca. 10 km to the west, may suggest a potential link. In addition, the Gran Mendoza area is located in a seismically active region, being particularly affected by several faults that cross-cut theurban area and were the triggers of large earthquakes in the last centuries. Comparably, both uranium deposits and active fault systems are present in the Punilla region, where indoor radon data are absent. The Punilla region occurs in a valley, where a large uranium deposit occurs at the eastern margin. Even though the location of this deposit is well-known since the 1960s, parts of the suburbs of the main cities of the region are located above it. The aim of this project is thus to provide the first systematic analysis of radon flow in the Gran Mendoza and Punilla areas. Radon passive detectors will be used to quantify indoor radon concentration, whereas field mapping of radon flow and gamma ray will be carried out using portable radon and gamma detectors. Consequently, a model of uranium and radon distribution and geochemical cycle for the studied areas will be obtained, allowing to provide unprecedented environmental constraints to evaluate epidemiological data and to establish potential mitigation strategies. On the long-term, this work is the first step towards the establishment of national surveys of radon flow and associated regulations.