Application of a mathematical model to an artificial aquifer under different recharge/discharge conditions using 222Rn as a tracer

Abstract

Radon (222Rn), a radioactive gas of natural origin, was listed by the World Health organization in 2009 as the second largest cause of lung cancer (3-14%) after tobacco. Global awareness of the importance of controlling its concentration in water led to the implementation of the european Directive 2013/51/Euratom, which establishes permitted levels in drinking water. This study applies a mathematical model to determine 222Rn concentration in water supplying an artificial aquifer over the full range of recharge/discharge conditions (volumes and times, and therefore flows). This was done by creating an artificial aquifer on a laboratory scale, which reproduces the recharges and discharges experienced by real aquifers through rainwater or groundwater. The equipment used in this study was an RTM 2100 with a specific system for continuous monitoring of 222Rn in water, a high-purity Ge detector for gamma spectrometry, and a portable liquid scintillation counter (LSC) called Triathler for specific measurements of 222Rn in water. The aim of this paper is to show the application of the mathematical model under different recharge/discharge conditions applied to the artificial aquifer. The concentration of 222Rn in water determined by the model can also be used as a tracer to find the origin and volume of water that reaches a real aquifer.