Depleted Uranium

The answers to these questions are a faithful summary of the scientific opinion produced in 2010 by "The Scientific Committee on Health and Environmental Risks" (SCHER):
"Opinion on the environmental and health risk posed by depleted uranium" Learn more...

1. Introduction

Use of depleted uranium (DU), particularly, in munitions, has prompted concerns about health risks of the material.

Previous expert reviews have concluded that there is no conclusive evidence of harm from exposure to DU, but these findings have been disputed.

The Scientific Committee on Health and Environmental Risks (SCHER) has reviewed existing reports and the latest scientific literature to assess the environmental and health risks of DU.

2. What is depleted uranium and how is it used?

Depleted uranium is a by-product of enrichment of natural uranium to make nuclear fuel. It is less radioactive than naturally occurring uranium as it contains less of the fissionable material U-235.

Uranium is an extremely dense metal, 1.7 times as dense as lead, and this lends itself to uses where a large mass in a small volume is advantageous. These include armour-piercing shells and bombs. DU-containing ammunition was used in both Gulf Wars, in 1991 and 2003, and in Serbia and Kosovo.

3. What are the health effects of radiation?

Radiation can cause radiation sickness due to immediate tissue damage. Such damage is seen after radiotherapy, industrial accidents, and use of nuclear weapons. Rapidly reproducing cells, such as those in the lining of the gut, the bone marrow, and the skin, are most affected. Very severe exposure causes tissue destruction and is rapidly fatal.

Radiation sickness is only seen above a threshold radiation dose. Such doses are not expected to be seen from any imaginable pathways of exposure to depleted uranium.

Radiation can also cause mutations in DNA, which increases the risk of cancer. The risk is usually assumed to increase with the dose with no minimum threshold.

Studies have not shown any definite link between numbers of tumours and radiation doses within the range of background radiation. This may be due to the difficulty of performing epidemiological studies involving such doses. However, there is also some recent biological evidence for a threshold in carcinogenic effects for both radiation and chemical damage.

4. Does depleted uranium pose a radiation hazard?

All uranium isotopes are radioactive. DU is appreciably less radioactive – usually around 40 per cent less - than unprocessed uranium. The activity is mainly in the form of alpha particles, which do not penetrate the skin. This means radiation hazards from uranium only arise from breathing in dust, eating or drinking contaminated food or water, or from shrapnel entering the body.

5. What other effects can depleted uranium have on human health?

All isotopes of uranium have the same chemical toxicity, and this is the likely cause of harm from depleted uranium.

The human toxicity of uranium is well-studied. Soluble compounds of uranium which are ingested in food or drink become concentrated in the kidneys, and kidney damage is the best-documented ill-effect of uranium toxicity. Studies confirm that the toxicity of DU is identical to naturally occurring uranium. Medical monitoring of Gulf War veterans who suffered shrapnel wounds involving uranium has not so far revealed any serious health effects.

6. What harmful effects can uranium have in the environment?

There is less data on ecological effects of uranium exposure than on human health effects. For human health, toxicity is the main likely cause of harm.

7. What is known about uranium exposure?

• 7.1 Natural exposure is a relevant comparison
• 7.2 What happens to depleted uranium in munitions?

7.1 Natural exposure is a relevant comparison

Uranium is naturally present in minerals and soil and, at lower levels, is found in food and drink. The average daily intake of natural uranium in humans is estimated as 1 to 2 μg from food and 1.5 μg from drinking water.

7.2 What happens to depleted uranium in munitions?

Armour-piercing shells which are on target generate uranium dust and larger fragments of the metal. The dust burns to uranium oxide, and is largely deposited over the inside of the target vehicle. Dust which escapes does not usually travel far because of the density of uranium metal.

DU munitions which hit the ground bury themselves in the soil, where the uranium oxidises and dissolves over years or decades. Over time, the uranium is removed from near the impact site. Total amounts are not high enough to add significantly to the natural uranium background.

Surveys of DU residues from combat zones show generally low concentrations of the metal, within the range of naturally occurring uranium, though there may also be a small number of "hot spots”.

Urine samples from serving soldiers and from civilians living in areas where DU ammunition has been used, typically indicate very low levels of DU exposure.

8. Do the data indicate any health risks or environmental risks from DU residues?

Human DU exposures and intake appear to be below established tolerable levels for uranium, for both chemical and radiological hazard. Environmental monitoring indicates that contamination in war zones is generally low, except in areas close to destroyed vehicles and penetrators. Risks to land-based and water-living life are low.

9. Conclusion

SCHER agrees with the conclusion of earlier expert reviews that environmental and human health risks due to a potential widespread distribution of DU are not expected. Exposure to DU is very limited compared to background exposures.

In combat zones, vehicles hit by DU should be made inaccessible to the general public and be properly disposed of. Used DU ammunition should also be collected and disposed of.