About 600 L of surface water were collected at the DYFAMED (Dynamics of atmospheric fluxes in the Mediterranean Sea) station (43°25’N - 07°52’E) in the Mediterranean Sea on 18 February 2001. The sample was filtered through a membrane filter with a 0.45 µm nominal pore size and no preservatives were added.
The sample was transferred into three 500 L containers, homogenized by mixing water between the containers for more than 8 hours, bottled in air-tight 1 L polyethylene bottles, and labelled with the code IAEA-418. The bottles containing 1 L of sea water each were sterilized according to ISO standards at 25 kGy (60Co) in an irradiation facility.
This Certified Reference Material is intended to be used for quality assurance purposes in the determination of 129I in sea water samples, including development and validation of analytical procedures, preparation and testing of reference methods, quality control, and training of analysts. This material is not to be used as calibrator.
Certified values
(Reference date for decay correction: 18 February, 2001)
| Radionuclide | Certified value | Expanded uncertainty * |
| 129I concentration | 2.3 × 108 atoms L-1 | 0.2 × 108 atoms L-1 |
| 129I volumic activity | 3.2 × 10-7 Bq L-1 | 0.3 × 10-7 Bq L-1 |
* Estimated expanded uncertainty with a coverage factor k=2, corresponding to a level of confidence of approximately 95%, as defined in the Evaluation of measurement data - Guide to the expression of uncertainty in measurement JCGM100:2008.
The assigned values were established on the basis of statistically valid results submitted to the IAEA Environment Laboratories, Monaco by 9 laboratories which had participated in an international interlaboratory comparison. The details concerning all reported results as well as the criteria for qualification as a certified or information value may be found in the respective report (attached).
