Laboratory analysis is a vital part of assessing the potential effect of any release of radioactivity into the environment, such as in areas where depleted uranium (DU) munitions have been used. Samples taken from such areas can be screened and analyzed to determine whether or not DU is present and to estimate the possible doses from different sources in that environment.
The IAEA Laboratories
at Seibersdorf, Austria have a number of different analytical techniques
and associated equipment to analyze both radioactive and stable isotopes
from a wide range of environmental sources. Staff at the laboratory
are not only able to do such testing, but also have the expertise to
organize and execute a comprehensive sampling campaign to obtain the
requisite samples for analysis.
The techniques and equipment used to analyze DU depends upon the nature of the sample and the sensitivity required to detect the anticipated level of DU. In the recent sampling carried out in Kosovo as part of the UNEP-led study, the Seibersdorf laboratory initially used a gamma-spectrometer to screen all the samples in order to determine which samples required further testing to identify more precisely and quantify the source of radiation detected. The gamma-spectrometer is very useful for screening large size samples (100 g to 2000 g). The gamma-spectrometer can typically detect DU in soil once its concentration exceeds 50 to 100 mg per kg. The majority of the 13 environmental samples tested by the Agency were soil samples. The samples were first labelled, catalogued, air dried, homogenized, and divided into 3 parts: one for archival purposes, one to study the physical characteristics, and one for destructive analysis to determine the concentration of DU. The physical characteristics (particle size and concentration) of DU are important because the most dangerous route of exposure is inhalation of small particles.
To carry on with the destructive analysis, the samples were further processed - the organic matter was removed by either oxidizing it at 500° C in a furnace or through microwave digestion incorporating chemical acid digestion. The resulting solutions were then tested using a sophisticated instrument that quantifies and qualifies the radioactive isotopes present. This instrument, known as an inductively coupled plasma mass spectrometer (ICP-MS), is able to detect minute quantities of uranium isotopes and can distinguish between natural and depleted uranium at the parts per trillion level (on samples in solution).
In addition to DU, the Seibersdorf laboratory has been involved in number of efforts (Chernobyl, Mururoa/Fangataufa Atolls, Bikini/Marshall Islands and Semipalatinsk) to monitor a wide range of radioactive elements in the environment. It is supported in its work through its IAEA ALMERA (Analytical Laboratories Monitoring Environmental Radioactivity) network, a global network of expert laboratories. Established in 1999, the network today has some 80 laboratories in 65 countries capable of providing radioanalytical support to the Agency in the radiological assessment of areas affected by accidental or intentional release of radioactivity. These laboratories are nominated by IAEA Member States and are chosen to be part of the network based on their expertise and performance in various proficiency tests specific to the needs of ALMERA.
Transfer of expertise through training is an Agency priority in which the Seibersdorf lab participates actively. Through the Technical Co-operation programme, fellows from Member States are trained in techniques and in the proper use of equipment to analyze radioactive and stable isotopes so that they will be able to strengthen the analytical capability in the their home countries.
With respect to DU, the laboratory will host a first training course on depleted uranium in the environment. Beginning in September 2001, this training course will give the 24 participating scientists practical training in the techniques used to analyze environmental samples for the presence of depleted uranium. It is intended for those countries affected by the release of depleted uranium in the environment or for those countries that may have deployed humanitarian or peacekeeping forces in affected countries. The course, provided with financial support from Germany, Switzerland, and Italy, will be held over a period of three weeks, two weeks combined at the VIC and the Agency's laboratory at Seibersdorf and one week at the Karlsruhe Research Center in Germany.