Interlaboratory Comparisons on the Determination of Total Activity of Drinking Water: What’s New?

Interlaboratory comparisons (ILCs) is an effective way to confirm the qualifications of laboratories performing mass screening of drinking water quality by the total radiation safety indicators (specific alpha and beta activity). By using two control samples (liquid and solid) with similar energy characteristics, close to the characteristics of calibration standards, we can identify inaccuracies at the stages of sample preparation and measurements, due to combining the study of the raw data presented in a visual form, correction for method bias (if necessary) and the robust estimates. Additionally, in determining acceptable results, it will be useful to apply non-statistical tolerances corresponding to the ILCs purposes. The influence of factors of incorrect sample preparation and calibration (graduation) was qualitatively assessed using the Rospotrebnadzor ILCs data (2021–2023) and the experimental laboratory studies