Abstract

We report the results from a pilot study on the use of Rn-222 ((222)radon) for river-aquifer interaction assessment in the Limari watershed, north-central Chile. Previous studies on this tool for such applications are not abundant at international level, and no records exist for Chile. The lowest Rn-222 levels (less than 1000 Bq/m(3)) were found in water reservoirs, thus indicating that this isotope is easily lost (and therefore usually absent) in surface waters. Conversely, the highest levels of Rn-222 were found in groundwater, with maxima activities around 20 000 Bq/m(3). This remarkable contrast allowed clear identification of zones of surface water-groundwater connectivity in the searched watershed domain.