Critical remarks on gross alpha/beta activity analysis in drinking waters: Conclusions from a European interlaboratory comparison

• Gross alpha/beta standard methods for drinking water analysis are discussed.
• Large spread of results (up to 2 orders of magnitude) observed in comparisons.
• Sources of interferences are reviewed.
• We propose to use true standardized methods to obtain better measurement results.

The most common gross alpha/beta standard methods used for drinking water analysis are discussed, and sources of interferences are reviewed from a metrological point of view. Our study reveals serious drawbacks of gross methods on the basis of an interlaboratory comparison analyzing commercial mineral water samples with the participation of 71 laboratories. A proposal is made to obtain comparable measurement results using true standardized methods.