(last updated 1 Apr 2002)
> See also: Radiation Exposure from Depleted Uranium Weapons
> Siehe auch: Infoblatt: Geschosse aus abgereichertem Uran (100k PDF in Deutsch)
Although the models used by the calculator are optimized for the situation experienced by former Wismut uranium miners, it can nevertheless be used for a first rough approach to assess the magnitude of the problem.
The calculator over-estimates the risk, since it assumes natural uranium rather than depleted uranium (the activity of which is only 60% that of natural uranium), and since it assumes that the uranium is in secular equilibrium with its decay products (what is not the case for depleted uranium).
In its theoretical assessment, UNEP's Balkans Task Force assumes a max. inhalation intake of 100 mg of DU close to the target and immediately after the attack. [BTF1999 p.58]
For this assessment, we assume that a 25-year old soldier experienced 10 such situations in 1995 in Bosnia (this is a clear over-estimate for allied forces' soldiers, since they came into the area only later). In case this soldier contracts leukemia in 2001, what is the probability of this leukemia being caused by the uranium?
Select "Inhaled U-238 Activity [kBq]" in the Parameter table and enter 12.4 in the year 1995 (this is the activity of 1 g U-238). Enter 1970 in Year of birth, 1995 in Year of first and last exposure, and 2001 in Year at risk.
The answer is: 1.7%. Thus, only one in 57 leukemias observed under the above circumstances could be attributed to the inhalation of uranium.
If the soldier had been exposed in 1999 (Kosovo war) rather than 1995, the result would have been zero, since the model assumes that no leukemia develops during the first 2 years after the exposure.
Other cancers, in particular liver cancer, become relevant only years later, as can be seen on the following screenshot for the above parameters. It shows the "Probability of causation", that is the probability of a certain cancer that has been contracted being caused from the radiation dose.
Note that the highest risk (contracting lung cancer) is not shown in the graph, since the model uses another approach to calculate lung cancer.
All these results must be used with caution, since they contain a number of assumptions, which don't necessarily apply to the specific situation in Kosovo.
A more detailed dose calculation shows that the risk of contracting leukemia is nearly completely caused from decay products present in uranium mines, but not found in depleted uranium. (see: Uranium Radiation Organ Dose Calculator)
| Inhalation of | ||
| 1 g Unat (with progeny) | 1 g DU (0.2% U-235) | |
| effective dose *) | 700 mSv | 120 mSv |
| Risk: | 3.5% (1 : 29) | 0.6% (1 : 167) |
| contribution to eff. dose from: | ||
| - Lungs | 88.0% | 99.7% |
| - Bone Surface | 6.2% | 0.057% |
| - Red Marrow | 3.4% | 0.072% |
| - Liver | 1.0% | 0.038% |
| - Testes/Ovaries | 0.96% | 0.037% |
With the red marrow being the target organ for leukemia, this means that, according to ICRP, the risk of contracting leukemia from inhalation of 1 g is 0.12% (1 : 830) for natural uranium with progeny, and 0.00043% (1 : 230,000) for depleted uranium.
An assessment of the estimated nuclide concentrations and resulting radiation doses shows that the inhalation dose for depleted uranium actually used in DU penetrators is only 0.7% higher than for DU produced from natural uranium. This increase is due to uranium-236 and possibly contained plutonium and neptunium.
> For details, see:
"To verify the level of transuranics in the DU stock material received from DOE, the Army tested representative samples from various batches of DU stock used to manufacture DU armor plate. From a radiological perspective, the transuranic contamination in DU armor contributed an additional 0.8 percent to the radiation dose from the DU itself." (Environmental Exposure Report - Depleted Uranium in the Gulf (II)Press articles published on January 18, 2001, clarify that this additional 0.8 percent includes the transuranics and U-236. So, the above assessment confirms the DOD figure.December 13, 2000)
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