²²²Rn in Argentina: A comprehensive review of environmental and hydrological applications

This work presents the first comprehensive review of studies conducted in Argentina on ²²²Rn, a naturally occurring radioactive noble gas with significant environmental and public health relevance. Fifty scientific publications were analyzed and thematically organized according to the medium of analysis (air or water) and their specific applications. In air, research has focused on indoor measurements, mining environments, and seismotectonic studies. Average indoor concentrations (41.6 Bq/m³) remain below the reference level recommended by the World Health Organization (100 Bq/m³), although high spatial and temporal variability has been reported and long-term monitoring remains scarce. In seismotectonic contexts, preliminary correlations between ²²²Rn emissions and seismic activity have been documented, suggesting its potential as a geophysical precursor. In aquatic environments, ²²²Rn has been successfully used to quantify groundwater contributions to rivers, lakes, and coastal systems, and to identify submarine groundwater discharge. Most studies highlight the control exerted by aquifer lithology, depth, and groundwater residence time on ²²²Rn concentrations. By synthesizing these findings and comparing them with international benchmarks, this review underscores both the advances and limitations of Argentine research, and emphasizes the need for integrated and long-term approaches to fully harness the potential of ²²²Rn as a tracer in sustainable water and environmental management.