Use of 222radon as a simple tool for surface water–groundwater connectivity assessment: a case study in the arid Limarí basin, north‐central Chile

We report the results from a pilot study on the use of 222Rn (222radon) for river–aquifer interaction assessment in the Limarí 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 222Rn levels (less than 1000 Bq/m3) 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 222Rn were found in groundwater, with maxima activities around 20 000 Bq/m3. This remarkable contrast allowed clear identification of zones of surface water–groundwater connectivity in the searched watershed domain.

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