Methodological Approaches to Radon in Water Measurements: Comparative Experiences between Romania and Spain

The EC Directive 2013/51/EURATOM of 22 October 2013 represents the first time that a radon limit for drinking water has been proposed. Transposition of this Directive into Spanish legislation was by means of the recent RD 314/2016 which sets a limit value of 500 Bq l(-1) for radon (Rn-222) in water for human consumption while that in Romanian legislation the Law 301/2015 provides a limit value of 100 Bq l(-1) for Rn-222 concentration in water for human consumption as well as a total effective dose of 0.1 mSv y(-1) from all radionuclides present in water (same dose value established by Spanish law). For several years, both in Romania and in Spain, there have been campaigns to measure the concentration of Rn-222 in waters of different origins in order to determine the possible exposure of the population through this irradiation path, and also to use the presence of radon dissolved in water as a source of indoor radon in thermal spa facilities, and also as a tracer of dynamic processes (C. Sainy et al., Sci. Tot. Envir. 543, 460 (2016); 1). In this article, an assessment of the results from measurement campaigns in both countries will be presented and compared. In addition, the different measurement techniques used will be described, and the description of an intercomparison exercise on radon measurement in water organized by the Environmental Radioactivity Laboratory of the University of Cantabria (LaRUC) will be presented, in order to evaluate the quality of the performance of the techniques used.