Uncertainty due to primary sampling of 222Rn in analyses of water

Michel Bruggeman; Liesel Sneyers; Wim Gijsbrechts; Hilde Loots; Damien Braekers; Marielle Lecomte

doi:10.1016/j.apradiso.2023.110741

Uncertainty due to primary sampling of ²²²Rn in analyses of water

Appl Radiat Isot. 2023 Jun:196:110741. doi: 10.1016/j.apradiso.2023.110741. Epub 2023 Feb 27.

Authors

Michel Bruggeman¹, Liesel Sneyers², Wim Gijsbrechts², Hilde Loots², Damien Braekers³, Marielle Lecomte⁴

Affiliations

¹ Research Centre SCK CEN, Mol, Belgium. Electronic address: michel.bruggeman@sckcen.be.
² Research Centre SCK CEN, Mol, Belgium.
³ Institut National des Radioéléments (IRE), Fleurus, Belgium.
⁴ Direction de la santé, Division de la radioprotection (DiSa), Luxembourg, Luxembourg.

PMID: 36878088
DOI: 10.1016/j.apradiso.2023.110741

Abstract

Measurement uncertainty is an important variable, to be accounted for when decisions have to be made based on measurement results. Measurement uncertainty is composed of two main components; one is related to the primary sampling, the other to the sample preparation and the subsequent analysis of the sample. The component related to the sample preparation and the analysis is commonly well evaluated in proficiency testing while there is generally no straightforward similar approach to evaluate sampling uncertainty. ISO 17025:2017 explicitly requires that testing laboratories performing sampling and analyses determine the uncertainty related to the primary sampling. In order to determine uncertainty arising in the primary sampling of ²²²Rn in water destined for human consumption, three laboratories IRE (BE), DiSa (LU) and SCK CEN (BE) initiated a joined sampling and measurement campaign. The dual split sample method in combination with ANOVA was used to evaluate the primary sampling uncertainty (precision) of the different methods. The tests showed that sampling bias is very probably, but that with good laboratory practice the sampling uncertainty precision and respectively bias can be kept below 5%.

Keywords: (222)Rn; ANOVA; Liquid scintillation counting; Sampling uncertainty.