Evaluation of the 2012 EC interlaboratory comparison on gross alpha/beta activity concentration in drinking water

An interlaboratory comparison was organized among 71 environmental radioactivity monitoring laboratories for the determination of gross alpha/beta activity concentration in drinking water. The performance of participating laboratories was evaluated with respect to the reference values using relative deviations. Sample preparation and measurement methods used by the participating laboratories are detailed, in particular in view of method-dependency of the results. Many of the participants' results deviate by more than two orders of magnitude from the reference values. This clearly demonstrates gross methods as unreliable and inaccurate in its present form and suggests revising the written standards for gross methods and restricting their application under clearly defined rules. Repeating this interlaboratory comparison is considered.