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Abstract: To realise radioactive environmental reference materials in Taiwan, seven environmental materials of soil, water, vegetation, meat, airborne particles (filter paper), milk and mushroom samples that are frequently encountered were used to establish the preparation of the reference materials. These seven environmental materials were collected, checked for freedom from radioactivity and prepared according to their properties. The preparation was carried out by using activity about 10–100 times that of the minimum detectable activity (MDA) in routine measurements in the radioactive standard used to spike the inactive material and this standard is traceable to national ionising radioactivity standards (TAF, 2004). To demonstrate sample traceability to the added standard, each sample was carefully measured and its uncertainty evaluated. Based on the recommendations of ISO Guide 35 for evaluation of reference materials and with the above assessment and verification procedures, the uncertainties (k=1) of the spike activity used in making reference materials were: 60Co≤4.6%, 134Cs≤4.7%, 137Cs≤5.0%, total β≤0.6% and 3H≤1.3%. [Copyright &y& Elsevier]

Abstract: A procedure using liquid scintillation counting for the monitoring of gross alpha and beta activities in environmental water was implemented to improve the conventional procedure using GFPC adopted in Taiwan. The new procedure was acquired through calibration and validation, and then was applied to the monitoring of surface water in Taiwan. This procedure can improve 2–4 times of detection efficiencies and takes only 70–80% of analysis time with reliable accuracy. With these features, the newly developed procedure is favorable during emergency situations. [Copyright &y& Elsevier]

Abstract: Seven kinds of spiked low-level activity samples were used for the 2004–2007 proficiency testing program in Taiwan. There were 711 reported data of Gross-β, 3H, 60Co, 90Sr and 137Cs were collected, and the bias, precision and traceability were evaluated. All the results were “Acceptable” for bias and precision, but 102 data were “Not Acceptable” for traceability. It reveals that the laboratories had good proficiency and well QA/QC management in routine practices, but the measurement uncertainty may be underestimated or overestimated. [Copyright &y& Elsevier]