Depleted uranium
Depleted uranium is a by-product of the production of uranium fuel used in nuclear power plants. It is used, for example, in aircraft counterweights and in the keels of sailboats. In addition, depleted uranium is used in munitions and missiles designed to destroy heavily armoured targets, such as tanks. Depleted uranium is used for its density and mass, not for its radioactivity.
Depleted uranium emits alpha, beta and gamma radiation. Alpha radiation is only relevant if the substance enters the body by inhalation. Beta radiation only exposes the skin, and its effects are more limited than that of alpha radiation. Gamma radiation is penetrating and causes exposure also externally. However, the gamma radiation emitted by depleted uranium is relatively weak.
Depleted uranium in crisis areas
Soldiers, peacekeepers and the civilian population may be exposed to depleted uranium in crisis areas.
When hitting a heavily armoured tank, the uranium heats up and catches fire. The combustion generates fine uranium dust, which can be transported into the lungs by inhalation. Soldiers may be exposed to uranium dust inside a destroyed tank or in its immediate vicinity immediately after destruction.
Uranium dust settles relatively quickly on the ground and binds to other materials on the ground. Small amounts can re-emerge in the air through dusting of the surface of the earth, which may expose people in the area. With the rains, the dust is also washed deeper into the soil.
It is very difficult to locate uranium warheads which have hit the ground with radiation meters. At a distance of approximately half a metre, the dose rate of radiation is at the level of background radiation. The ground layers attenuate radiation, so it is often impossible to locate the warheads which have sunk into the ground based on radiation. Warheads should be collected, especially from residential areas and children's playgrounds. However, in many areas, clearing is difficult due to the risk of mines.
Very little is known about the health effects of depleted uranium. However, there is a wealth of information available on populations exposed to natural uranium and enriched uranium. The radiation risk and cancer risk of depleted uranium are significantly lower.
The health risks are mainly related to the chemical toxicity of uranium. In uranium mines and enriched uranium plants, even extensive studies have not found a link between uranium exposure and leukaemia.
Depleted uranium was used in munitions in the Balkans and the Gulf War in the 1990s, in Afghanistan and Iraq in the 2000s and probably also in Lebanon. During the Second Persian Gulf War (2003–2011), Allied forces fired on tanks with depleted uranium ammunition. After the war, many veterans experienced strange symptoms that were, it was suspected, caused by exposure to depleted uranium.
In general, the cause of the symptoms of veterans of the Gulf War has not been proven. It is not totally clear whether the symptoms were caused by depleted uranium. In wartime situations, toxic substances are released into the air from various sources, such as explosive gases, missile fuels and bombed factories.
People in the war zone may have inhaled small particles of uranium, which were spread in the air when the munitions exploded. Inhalation of depleted uranium particles slightly increases the risk of lung cancer over the years. From the lungs, uranium enters the bloodstream and is transported to the kidneys, where it can cause damage, just like other heavy metals. However, the risk is small, as the amount of uranium is low. The higher risk is usually due to other heavy metals used in military equipment, such as lead, which have been used in greater quantities in such equipment.
In certain areas, there may be large amounts of natural uranium in the soil and bedrock. High concentrations of uranium have been measured especially in the bore well water of southern Finland.
Further information:
- Porakaivoveden radon- ja uraanikartasto (Bore well radon and uranium atlas) (STUK-A 256) (julkari.fi)
- Kaivoveden uraanista Terveyden ja hyvinvoinnin laitoksen internetsivuilla (thl.fi) (About the bore well uranium at the National Institute for Health and Welfare’s website)
- Uraani kaivostoiminnassa (Uranium in mining) (STUK brochure, 2013) (julkari.fi)