A sample of about 158 kg of sediment was collected by IAEA-MEL in July 1996 in Fangataufa Lagoon (French Polynesia), where nuclear weapon testing had been carried out. The sediment was frozen for 2 hours at -40°C, then freeze-dried with a +5°C increase in temperature per hour. Secondary drying was done over 24 hours under a pressure of 0.02 mbar at a constant temperature of +40°C. The sediment was then ground into powder, sieved at 250 µm and homogenized under nitrogen gas. The samples were then bottled in flasks under nitrogen gas, sealed with polyethylene caps and labelled with the code IAEA-384. The bottles containing 100 g of sediment powder each were sterilized according to ISO standards at 25 kGy in an irradiation facility.
Reference date for decay correction: 2019-01-01
Certified values for massic activities
| Radionuclide | Certified value [Bq kg-1] | Expanded uncertainty [Bq kg-1] |
| ⁴⁰K | 6.9 | 0.9 |
| ⁶⁰Co | 0.131 | 0.003 |
| ¹⁵⁵Eu | 0.266 | 0.016 |
| ²³⁰Th | 2.50 | 0,10 |
| ²³⁸U | 36.4 | 1.2 |
| ²³⁸Pu | 32.7 | 0.6 |
| ²³⁹⁺²⁴⁰Pu | 108 | 13 |
| ²⁴¹Am# | 9.3 | 1.0 |
*The uncertainty is expressed as an expanded uncertainty using a coverage factor k = 2 estimated in accordance with the JCGM 100:2008 'Evaluation of measurement data - Guide to the expression of uncertainty in measurement' [1] and ISO Guide 35 [2].
•Americium-241 values should be corrected for ingrowth from 241Pu.
The values listed above were established on the basis of statistically valid results submitted by laboratories which had participated in an international interlaboratory comparison organized by the IAEA Marine Environment Laboratories, Monaco. The details concerning the criteria for qualification as a certified or information value may be found in the report IAEA/AL/126 (attached).
