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Now published: "Modern routine methods and quick procedures for the determination of Sr-89 and Sr-90 in environmental monitoring"


For this reason, a working group of the "Environmental Monitoring" team in the Trade Association for Radiation Protection has in the last few years summarized the status of the radiochemical analysis and activity measurement methods for determination of the radionuclides Sr-89 and Sr-90 in environmental samples, taking quick procedures for incident and accident situations into account. The book covers the developments of the last approx. 15 years, e. g. the use of extraction-chromatography procedures or the use of Low-Level Liquid Scintillation Counting (LSC) as an alternative to the proportional counter. All relevant partial steps are described in the form of single modules (as of the end of 2006). First of all, the often sample-specific sampling and sample preparation procedures are presented on the basis of the practical work flow in the laboratory. After that, the radiochemical separation and cleaning steps and the procedures for the preparation of the activity measuring sources are described. One chapter is dedicated to the activity measurement methods and the determination of the analysis results as well as to the measurement uncertainties. Here, it has been particularly important to integrate as much practical experience as possible from the laboratories of the 11 authors who perform environmental radioanalyses themselves. This is why a beginner in this field of work will not only be given a comprehensive survey but also many instructions for the avoidance of radiochemical interferences or metrological problems.

In addition, one chapter informs about a (brief, but sufficient) documentation and validation of the methods described, taking the requirements for a quality management system in accordance with standard DIN EN ISO/IEC 17025 into account. Moreover, an assessment regarding the applicability of the procedures is made, allowing for the different imaginable scenarios during monitoring of the environment of nuclear facilities and during monitoring of the radioactivity in the environment in accordance with the Precautionary Radiation Protection Act.

One of the focal points of PTB's activities in the practical work for the preparation of the book was the coordination of the method validation. For this purpose, PTB has provided two activity standard solutions "A" and "B" which - in addition to Sr-89 and Sr-90 - also contained radionuclides which may disturb radiochemical cleaning or the activity measurement. The activities of Sr-89 and Sr-90 were - on the one hand - in a range which is typical of environmental samples. On the other hand, they furnished, however, count rates for the measurements which were still sufficiently large even under realistic general conditions (e. g. matrix effects, bad yields, interfering nuclides etc.).

Activity standard solution "A" was used for the validation of the radiochemical separation processes with the aim of

  • checking the completeness of the radiochemical separation and the determination of the achievable radiochemical purenesses of the measuring sources,
  • elaborating recommendations for the optimization of separation and cleaning steps,
  • optimizing the radiochemical yields,
  • determining problematic matrix effects,
  • elaborating recommendations for the elimination of problematic matrix effects,
  • comparing the analysis results with the default theoretical activities.

In the laboratories of the authors, known volumes of the activity standard solution were added to their usual environmental samples. At that moment, the exact activities of the radionuclides contained in the samples were not yet known. They were - analog to the procedure of an intercomparison - only disclosed after PTB had been informed about the analysis results, whereby the calibration certificates for the solutions supplied individually to the participants were dispatched by PTB.

In contrast to this, the activity standard solution "B" was sent jointly with the calibration certificates in order to

  • calibrate LSC measuring instruments,
  • test or optimize procedures for the evaluation of LSC spectra,
  • compare the measurement results with predetermined theoretical activities.

In addition, the results of the participation in external intercomparisons (national and international) in which the authors had successfully participated in the last few years and in which the procedures presented in the book were applied, are shown in a synoptical table.

Finally, the technical Annex contains a lot of very detailed information for the laboratory practitioner which would have gone beyond the scope of the modules in the text part. In spite of its abundance of information, the book cannot be regarded as a "panacea" for the handling of all kinds of environmental samples. In fact it recommends proven and validated analysis and measurement methods which a user may combine with "his" separation process, which must be optimized for the requirements of the laboratories (e. g. required sample mass, required detection limit, radiochemical yields, existing measuring devices, available measurement times, organization of staff and work).

The book has been published in February 2008 in the publication series "FORTSCHRITTE IM STRAHLENSCHUTZ (PROGRESS IN RADIATION PROTECTION)" of the Trade Association for Radiation Protection under the number FS-08-147-AKU. Publisher: TÜV Media GmbH, Cologne. It has a volume of approx. 210 pages and also contains a CD with the contents. ISSN: 1013-4506, ISBN: 978-3-8249-1119-6.