Determination of radium-226 in environmental and personal monitoring samples

Radium-226 is a member of the Uranium-238 natural decay series and is the most hazardous radionuclide released to the environment from uranium mining and milling. Due to its long half-life (1600 years) and radiological effects it is one of the most important isotopes to be determined among the naturally occurring nuclides in environmental samples. It is also among the most toxic long-lived alpha-emitters present in environmental samples, as well as one of the most widespread. The requirement for the determination of radium has become a matter of interest in public health due to its hazardous nature with respect to internal exposure. It is concentrated in bones, thus increasing the internal radiation dose of individuals. The methodology developed involves dissolving solid samples by microwave digestion. The radium is then separated from matrix interferents by cation exchange chromatography and subsequently electrodeposited onto a stainless steel disc. Alpha-Spectrometry is employed to determine the activity in the sample. A limit of detection of 20 mBq l(-1) for ground water samples (100 ml) and 20 mBq g(-1) for solid samples (0.1 g) is achievable. The method has been validated via an intercomparison exercise and analysis of a marine sediment reference material. Samples analysed include run off waters from uranium mines, coal and fly ash and also trapping media such as silica gel, charcoal and activated carbon.