Features: Depleted Uranium

Burkart

IAEA Deputy Director General Werner Burkart is a Professor of Radiation Biology and Environmental Health, who before coming to the Agency was a director of the Institute for Radiation Hygiene of the Federal Office of Radiation Protection in Germany, which assists in monitoring German peacekeeping forces serving in the Balkans.

The IAEA's Plan of Activities:
An Interview

The use of depleted uranium ammunition has raised concerns about potential health effects. WorldAtom spoke with Werner Burkart, Deputy Director General of the Department of Nuclear Sciences and Applications about these concerns and activities underway in the Agency.

What is the difference between depleted uranium (DU) and natural uranium?

Uranium is a naturally occurring element and has three principal radioactive isotopes: U-238, U-235, and U-234. Uranium is present in small amounts in water, soil, rocks, food and air.

Depleted uranium is a by-product of the process of uranium enrichment (for making nuclear fuel) and is about 60% as radioactive as natural uranium. DU is almost entirely U-238 because most of the radioactive isotope U-234 and about two thirds of the U-235 are removed. In addition to its military applications (to improve the penetration of armour-piercing ammunition, for example), DU has a number of commercial applications such as neutron detectors, staining in electron microscopy, ship ballast, and counterweights for airplanes.

What are the potential health concerns from use of DU?

To be honest, there are very few health concerns for DU from a radiological point of view, because it is only very slightly radioactive. Even the handling of enriched uranium in industry does not need special protection such as shielding. There are more dangerous radiotoxic elements associated with uranium in nature such as its natural decay products radon/radon progeny and radium. Contrary to uranium proper, radon progeny as indoor pollutants contribute sizeably to our radiation exposure. DU is devoid of this radiotoxicity

The effects of DU depend on the route and magnitude of exposure (ingestion, inhalation, contact, or wounds) and the characteristics of DU (particle size and solubility). The potential health risk from chemical toxicity would arise from ingestion or inhalation of soluble depleted uranium (DU) which - at higher exposure levels - could lead to kidney damage. The potential radiological risk would arise from inhalation of insoluble DU oxides that could reside for an extended period in the lung and lung lymph nodes, or from ingestion of soluble DU that could lead to exposure of bone and other tissues. In my view, it is difficult to imagine that peacekeepers in the Balkans had exposure to DU high enough to significantly change their normal level of radiation exposure from natural and civilian sources. In this context, it has to be remembered that each cubic metre of top soil in Europe already contains about 10 g of natural uranium with all its radiotoxic decay products. Although this leads to measurable levels of uranium in drinking water and in the human body, little radiation exposure results from this radioactivity, as compared to radon progeny and external radiation from natural terrestrial and cosmic sources. For instance, some areas in Finland show largely elevated uranium levels in drinking water from wells, which lead to body contents much higher than what can be expected in Kosovo. No increase in cancer has been detected in such chronic exposure situations.

Can you tell us about your experience in studying radioactive metals like depleted uranium?

During my training in public health at the Institute of Environmental Medicine at New York University, we studied the metabolism of curium, another actinide element above plutonium and americium, in baboons. It can be said that for all these elements the uptake in the gut is quite low, even for the most soluble compounds. The critical path is, therefore, through inhalation of very fine particles. This is true for depleted uranium. This kind of exposure, to aerosolized particles, would only be present during combat and -- to a lesser extent -- for those crews dealing with military vehicles hit by DU ammunition.

Can you tell us more about the activities underway with respect to DU?

What we can provide at this stage is highly sophisticated measurement and analytical methods, equipment, and experts at the Agency’s Seibersdorf Laboratories because measurement of the different isotopes of uranium and of minute amounts of actinides such as plutonium or americium is very important for the safeguards activities of the Agency.

As mentioned in the UNEP/IAEA press release on 25 January 2001, the Agency is currently preparing an interregional training course on "Depleted Uranium in the Environment". The course will provide up-to-date knowledge and practical training in the analysis, biomonitoring, environmental and health assessment of DU and actinides in the environment. Aimed at participants from countries that are affected by environmental releases of DU or that provide peacekeeping or humanitarian forces to countries affected by DU use, the course is being planned to take place in the Agency’s Seibersdorf Laboratories in the second half of 2001.

In addition, the Agency has initiated a co-ordinated research project on the "Radiochemical, Chemical and Physical Characterisation of Radioactive Particles in the Environment." This project will have a special emphasis on DU and contribute to building a stronger scientific basis for developing adequate radioanalytical and physical procedures for identifying and characterizing environmental particles in view of their impact on humankind.

The Agency has also budgeted resources for two new projects related to DU. The first will provide training to laboratory staff from Member States in the measurement and assessment of terrestrial radioactivity at contaminated sites. With the second project, the Agency will generate new experimental techniques and reference materials for the characterization of radioactive particles in the environment. These projects are planned to start next year.

Anything you would like to add?

In order to address and alleviate widespread concerns about the effects of DU, a systematic approach should be taken to measure, analyze, monitor, and evaluate the potential effects of DU on environment and health. As mentioned previously, the UN is exploring the feasibility of sending additional fact-finding missions to other places where DU may have been used, specifically Bosnia and Herzegovina, the Federal Republic of Yugoslavia, Iraq and Kuwait. The Agency is ready to contribute specialists and analytical capacities.