IAEA-326 Soil IAEA-327 Soil
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XA0102533 IAEA/AL/100 REPORT ON THE INTERCOMPARISON RUN FOR THE DETERMINATION OF RADIONUCLIDES IN SOILS IAEA-326 AND IAEA-327 R. Bojanowski, Z. Radecki, M. J. Campbell, K. I. Burns and A.Trinkl Analytical Quality Control Services, Agency's Laboratories, Seibersdorf International Atomic Energy Agency P.O. Box 100 A-1400 Vienna, Austria April 2001 CONTENTS Page 1. Introduction 1 2. Description of the materials 1 3. Scope of the study 2 4. Preparation of samples 3 5. Homogeneity test 4 6. Sample dispatch and data return 5 7. Treatment of data 5 7.1. Routine procedure 5 7.2. Some shortcomings 6 7.3. Modification to the data evaluation process 6 7.3.1. Reassignment of short-lived primordial progeny of long-lived radionuclides 6 7.3.2. Validation of results 7 8. Evaluation procedures 7 9. Explanation of tables and figures 8 9.1. Datatables 8 9.2. Method performance tables 11 10. Results and discussion 12 10.1. Dry/wetratio 12 10.2. Potassium-40 12 10.3. Strontium-90 13 10.4. Ruthenium-106 16 10.5. Antimony-125 16 10.6. Caesium-134 17 10.7. Caesium-137 (sample IAEA-327 only) 17 10.8. Europium-154 17 10.9. Europium-155 18 10.10. Lead-210andPolonium-210 18 10.11. Radium-226 21 10.12. Radium-228 24 10.13. Thorium-228 25 10.14. Thorium-230 27 10.15. Thorium-232 28 10.16. Uranium-234 30 10.17. Uranium-235 32 10.18. Plutonium-238 34 10.19. Uranium-238 36 10.20. Plutonium-239+240 39 10.21. Americium-241 40 10.22. Other radionuclides 42 10.23. Trace Elements 43 11. Concluding remarks 44 12. References 45 TABLES Table 1 Approximate major chemical and mineralogical composition [%] 2 Table 2 Distribution of Cs-137 in IAEA-326 and IAEA-327 4 Table 3 Homogeneity data for Cs-137, Ac-228 and K-40 in soil sample IAEA-326 5 Table 4 Allocation of Misascribed Analytes to their Proper Categories 6 Table 5 Method Codes Used in this Intercomparison 10 Table6 Moisture content for IAEA-326 and IAEA-327 12 Table 7a Performance of Methods Used for the Determination of Sr-90 in Soil Samples IAEA-326 and IAEA-327 15 Table 7b Percentage Contribution of Results to the Reference Values of Sr-90 in IAEA-326 and IAEA-327 by Method Type 16 Table 8a Performance of Methods Used for the Determination of Pb-210 in Soil Samples IAEA-326 and IAEA-327 20 Table 8b Percentage Contribution of Results to the Reference Values of Pb-210 in IAEA-326 and IAEA-327 by Method Type 21 Table 9a Performance of Methods Used for the Determination of Ra-226 in Soil Samples IAEA-326 and IAEA-327 23 Table 9b Percentage Contribution of Results to the Reference Values of Ra-226 in IAEA-326 and IAEA-327 by Method Type 24 Table 10a Performance of Methods Used for the Determination of Th-228 in Soil Samples IAEA-326 and IAEA-327 26 Table 10b Percentage Contribution of Results to the Reference Values of Th-228 in IAEA-326 and IAEA-327 by Method Type 26 Table lla Performance of Methods Used for the Determination of Th-230 in Soil Samples IAEA-326 and IAEA-327 28 Table 1 lb Percentage Contribution of Results to the Reference Values of Th-230 in IAEA-326 and IAEA-327 by Method Type 28 Table 12a Performance of Methods Used for the Determination of Th-232 inSoil Samples IAEA-326 and IAEA-327 29 Table 12b Percentage Contribution of Results to the Reference Values of Th-232 in IAEA-326 and IAEA-327 by Method Type 30 Table 13a Performance of Methods Used for the Determination of U-234 in Soil Samples IAEA-326 and IAEA-327 31 Table 13b Percentage Contribution of Results to the Reference Values of U-234 in IAEA-326 and IAEA-327 by Method Type 31 Table 14a Performance of Methods Used for the Determination of U-235 in Soil Samples IAEA-326 and IAEA-327 33 Table 14b Percentage Contribution of Results to the Reference Values of U-235 in IAEA-326 and IAEA-327 by Method Type 34 Table 15a Performance of Methods Used for the Determination of Pu-238 in Soil Samples IAEA-326 and IAEA-327 35 Table 15b Percentage Contribution of Results to the Reference Values of Pu-238 in IAEA-326 and IAEA-327 by Method Type 35 Table 16a Performance of Methods Used for the Determination of U-23 8 in Soil Samples IAEA-326 and IAEA-327 37 Table 16b Percentage Contribution of Results to the Reference Values of U-238 in IAEA-326 and IAEA-327 by Method Type 38 Table 17a Performance of Methods Used for the Determination of Pu-239+240 in Soil Samples IAEA-326 and IAEA-327 39 Table 17b Percentage Contribution of Results to the Reference Values of Pu-239+240 in IAEA-326 and IAEA-327 by Method Type 40 Table 18a Performance of Methods Used for the Determination of Am-241 in Soil Samples IAEA-326 and IAEA-327 41 Table 18b Percentage Contribution of Results to the Reference Values of Am-241 in IAEA-326 and IAEA-327 by Method Type 41 Table 19 Additional Radionuclide Information 42 Table 20 Stable Elements in IAEA-326 and IAEA-327 Intercomparison Materials 43 FIGURES Figure 1 Particle size distribution of IAEA-326 and IAEA-327 3 Figure 2 Performance of the methods used for the determination of Sr-90 in soil samples: a) IAEA-326; b) IAEA-327 14 Figure 3 Performance of the methods used for the determination of Pb-210 in soil samples: a) IAEA-326; b) IAEA-327 19 Figure 4 Performance of the methods used for the determination of Ra-226 in soil samples: a) IAEA-326; b) IAEA-327 22 Figure 5 Performance of the methods used for the determination of Th-228 in soil samples: a) IAEA-326; b) IAEA-327 25 Figure 6 Performance of the methods used for the determination of Th-230 in soil samples: a) IAEA-326; b) IAEA-327 27 Figure 7 Performance of the methods used for the determination of Th-232 in soil samples: a) IAEA-326; b) IAEA-327 29 Figure 8 Performance of the methods used for the determination of U-235 in soil samples: a) IAEA-326; b) IAEA-327 33 Figure 9 Performance of the methods used for the determination of U-238 in soil samples: a) IAEA-326; b) IAEA-327 36 APPENDICES Appendix I Individual Laboratory Mean Results for IAEA-326 Appendix II. Individual Laboratory Mean Results for IAEA-327 Appendix III. S-shape Plots for IAEA-326 Appendix IV. S-shape Plots for IAEA-327 Appendix V. List of Participants Appendix VI. IAEA-326 Reference Sheet Appendix VII. IAEA-327 Reference Sheet 1. INTRODUCTION In 1994, as a part of its AQCS programme, the IAEA organized an intercomparison study to determine the activity concentrations for a range of radionuclides in two different types of soil. The participation was open to all interested laboratories and was advertised by means of an invitation letter sent to laboratories that had previously expressed an interest in such an exercise. The soils were obtained from Russia, under a special agreement with the Khlopin Radium Institute, St. Petersburg, which undertook to collect and process the raw material prior to its distribution to the participants. In common with similar intercomparison exercises organised in the past, this project had two goals: 1. to give the participants an opportunity to check their analytical performance, 2. to acquire results which would help assign reference values for appropriate radionuclides in the two samples. In order to ensure anonymity, each laboratory was assigned a unique code number which was known only to the laboratory concerned and AQCS. 2. DESCRIPTION OF THE MATERIALS The materials were collected in 1990 from two geographically distinct sites within the former Soviet Union and designated as IAEA-326 and IAEA-327. In both cases, only top soil to a maximum depth of 20 cm was collected. IAEA-326 was a black soil collected at a site located in the Kursk region whereas IAEA-327 was a podsolic soil obtained from a site, close to Moscow. The total weight of each material collected was approximately 350 kg. Their approximate chemical and mineral compositions are shown in Table 1. Page 1 of45 Table 1 Approximate major chemical and mineralogical composition [%] Component IAEA-326 Soil IAEA-327 Soil SiO2 69.53 78.33 TiO2 0.75 0.84 A12O3 10.37 9.57 Fe2O3 3.81 2.98 MnO 0.077 0.07 MgO 1.02 0.77 CaO 1.63 0.81 K2O 2.29 2.47 Na2O 0.8 1.15 P2O5 0.17 0.075 Humic substances 5.7 0.7 Mineralogical composition Quartz 30 - 40 40 - 50 Spar 8-12 4-10 Mica 4-8 3-6 Other major minerals 4-7 3-6 Chlorite 4-8 2-4 Montmorillonite 8-15 5-12 Kaolinite 3-8 6-15 Mixed clay minerals 4-10 3-8 Iron hydrous oxides 2-4 3-6 Accessory minerals 4-7 3-5 3. SCOPE OF THE STUDY The aim of this intercomparison was for participants to analyse as many anthropogenic radionuclides in the two soil materials as possible. These soils would then serve as natural matrix reference materials that could be used for quality assurance purposes in support of environmental radionuclides monitoring programmes Participants were not specifically instructed as to which radionuclides were to be measured.