Natural radium isotopes in waters determined with gamma-ray spectrometry using a HPGe detector

Abstract

This paper describes a methodology developed to measure the activity concentration of the four natural radium isotopes 226Ra, 228Ra, 224Ra and 223Ra in water samples, using γ-ray analysis performed with a hyperpure germanium detector (HPGe). The detector efficiency was properly determined using a set of thorium standards exhibiting concentrations between 10 and 10,000 μg/g. The developed analytical protocol was applied for evaluating the radium activity concentration in groundwater samples providing from different aquifer systems in three Brazilian states. The results were compared with the guideline reference values for 226Ra and 228Ra as proposed by the Brazilian and WHO legislations.