Determining radon equilibrium concentrations from core samples

Abstract

Radon (Rn-222) is commonly used as a tracer to identify where rivers gain and lose water to groundwater (Cartwright & Hoffman), 2016; Cook et al., 2006). However, it's utility as a quantitative tracer is limited by the need to know the secular equilibrium value for the associated sediments. For practical reasons, an equilibrium value is often estimated from groundwater samples, and the Rn-222 distribution in the sediments is assumed to be homogenous. The aim of this study was to determine if Rn-222 equilibrium values can be estimated via laboratory-based sediment batch immersions. This study looked at four different methods using a Durridge Rad7 to measure radon equilibrium values from alluvial sediments.