Evaluation of variability in radionuclide measurements in drinking water

摘要

A blind interlaboratory study of radium-226 (Ra-226), radium-228 (Ra-228), and gross alpha and beta activity was conducted among five multistate certified laboratories to examine concerns regarding analytical variability for compliance with the revised Radionuclides Rule. Results of the interlaboratory study demonstrated that although Ra-226 and gross beta measurements appeared to be both accurate and precise, even at low levels, Ra-228 and gross alpha measurements were much less robust both within and among laboratories, which could result in potentially incorrect compliance decisions. There are several steps that utilities can take to improve reliability of compliance data, including mandating specific quality control (QC) steps by laboratories and ensuring that they follow the QC guidance in the US Environmental Protection Agency's laboratory certification manual and the Multi-Agency Radiological Laboratory Analytical Protocols Manual, even though these may not always be enforced by laboratory certification authorities.