Depleted uranium (DU): general information and toxicology
Information on depleted uranium (DU) including what it is, its uses, health effects and protection from exposure.
What is uranium?
Uranium (chemical symbol U) is a silver-coloured heavy metal, similar to lead, cadmium and tungsten. Like tungsten it is very dense, about 19 grams (g) per cubic centimetre (cm), nearly twice as dense as lead. Thus a 10 cm cube would weigh 20 kilograms (kg). Uranium occurs naturally, and is found in all rocks and soil, and in water and air. It occurs in soils at an average concentration of about 2 parts per million, equivalent to 2 g per tonne. Put another way, the top metre (m) of soil in a typical garden (one-tenth of an acre, or 10 m by 40 m) contains about 2 kg of uranium.
Uranium is often described as being ‘pyrophoric’. This means that fine dust particles such as those produced when uranium metal is machined may catch fire spontaneously in air. Small pieces may ignite in a fire, and burn. However, tests have shown that large pieces, like the penetrators used in anti-tank weapons, or aircraft balance weights, will not normally ignite in a fire. As long as heat (and air) are applied, such large pieces will gradually oxidise. The uranium is converted to uranium oxide powder, but this does not readily disperse in the air unless the fire creates a lot of turbulence, or is accompanied by explosions.
In its natural state, uranium consists of 3 isotopes (uranium-234, uranium-235 and uranium-238). In any quantity of natural uranium, these are found, by weight, as follows:
The half life of a radioactive isotope is the time taken for it to decay to half of its original amount.
What is depleted uranium (DU)?
An ‘enriched’ form of uranium, in which the uranium-235 concentration is enhanced, is required to produce energy both in nuclear reactors and nuclear weapons. The remaining uranium mixture (after the enriched uranium is removed) has reduced concentrations of the uranium-235 and uranium-234 isotopes; this is known as depleted uranium (DU).
Typically, DU used in munitions contains by weight:
If the DU is partly derived from reprocessed reactor fuel, then it may also contain uranium-236 (approximately 0.0003%) and trace amounts of plutonium, neptunium, americium and fission products.
Further information can be found on the website of the US office of the special assistant to the Secretary of Defense for Gulf War Illnesses. Particular sections of interest from the ‘Environment Exposure Report, Depleted Uranium in the Gulf (II)’; depleted uranium - a short course and properties and characteristics of DU. It is suggested that users run a search on ‘transuranics’.
Since the radioactivity per gram of each uranium isotope is different, the ratios of isotopes in natural and depleted uranium are different if expressed by radioactivity (see table below) rather than by mass.
|Isotope||% of isotope by radioactivity - natural uranium||% of isotope by radioactivity - depleted uranium|
How radioactive is DU?
DU is less radioactive than natural uranium because it has less of the more radioactive isotopes, uranium-234, and uranium-235, per unit weight than does natural uranium.
The International Atomic Energy Agency (IAEA) defines DU as a low specific activity material. Specific activity (the activity in becquerels per unit mass) is used as a measure of how radioactive something is. An activity of 1 becquerel (Bq) means on average 1 radioactive decay takes place per second. The specific activity of uranium in DU is about 15 Bq per mg (1 milligram, mg, is 0.001 g) compared with 25.4 Bq per mg for natural uranium. If the activity of the decay products is also included, then the value for specific activity is higher. Plutonium (for example, plutonium-239) has a much higher specific activity of about 2,300,000 Bq per mg while granite has an activity of 0.00005–0.0005 Bq per mg of granite.
Where is DU used?
Uranium is used mainly as fuel for nuclear power reactors. Before the use of nuclear energy, relatively small amounts were used, for example as pottery glaze and glass pigment.
DU has both civil and military applications.
The high density of DU makes it useful as a counterbalance in some aircraft. It is also sometimes used to shield radiation in hospital radiotherapy units, for containers for radioactive sources, and in heavy industrial drilling equipment.
The main military use of DU is in projectiles designed to penetrate armour (for example, tanks). These projectiles (known as ‘kinetic energy penetrators’) consist simply of rods of uranium metal (alloyed with a small amount of titanium) fired at very high speed. Uranium is used because it has a high density, and is readily available. The ability of DU to self-sharpen as it penetrates armour is the main reason why it is more effective than the alternative, tungsten, which tends to mushroom on impact.
When DU penetrators strike a solid object, like a tank’s armour plating, they can go straight through it before erupting in a burning cloud of dust and metal fragments. The high temperature fragments created as DU passes through armour can spread to strike anything inside a tank and set fire to its fuel and ammunition. DU is also used defensively, since its physical properties give advantages in armour plate.
When is DU harmful?
Many factors determine the potential harmful effects of DU, depending on whether the exposure is external (outside the body) or internal (inside the body).
Outside the body
For DU outside the body, the potential effects are limited to those of radiation and not chemical toxicity. The radiation exposure depends on how much DU is present, how close it is and how long it is there. It is relatively straightforward to calculate (or measure) such radiation exposures and to assess their effects. DU emits 3 types of ionising radiation: alpha particles, beta particles and photons (x-rays and gamma rays). Alpha particles (nuclei of helium atoms) are stopped by a sheet of paper, and most will be stopped by the inert outer layer of skin. Beta particles (high speed electrons) can travel about a centimetre in the body. Photons (x-rays and gamma rays) are more penetrating and can pass straight through the body.
The radiation dose-rate to the skin, which comes mainly from the beta particles, can be up to 2.5 millisieverts (mSv) per hour, if a lump of DU were held in the hand. It is easily reduced by wearing gloves, or if the DU is encased in some other material. Furthermore, skin is relatively insensitive to radiation, so that even continuous contact (keeping a piece in a pocket or wearing it as jewellery) is unlikely to produce a radiation burn or other short-term effect. Such effects require doses of a few thousand millisieverts, delivered over a short time, but at 2.5 mSv per hour, the DU would need to be in contact for months to give such doses. There would, however, be expected to be a small increase in the risk of skin cancer.
The theoretical maximum whole body gamma dose-rate from external exposure, for someone surrounded by DU, has been calculated to be 0.025 mSv per hour (0.6 mSv per day). The highest exposures likely to arise in practice are in a vehicle fitted with DU armour and carrying DU ammunition. According to US Army measurements, the whole-body dose-rate in a tank fully loaded with DU munitions is typically less than 0.002 mSv per hour. Thus driving such a tank for 1,000 hours gives a dose similar to the average annual dose from natural background radiation in the UK. Such exposures are readily measured and controlled.
Inside the body
If DU enters the body, it can potentially cause damage from the inside (internal exposure) either through irradiation or by chemical action. It can enter the body by inhalation (breathing in fine dust), ingestion via the mouth, contamination of an open wound, or, on the battlefield, by the embedding of shrapnel fragments. Because uranium has been used extensively as a nuclear fuel, and many workers involved in processing uranium have been potentially exposed to dusts containing uranium, over many years, there have been many studies carried out on the behaviour of uranium in the body. In particular, there have been numerous studies conducted to determine the behaviour of uranium in the body after deposition in the lungs of a wide range of different uranium compounds, including the various oxides produced by the use of DU munitions.
What happens to DU inside the body?
Inhaled DU particles may enter the body through the nose and the mouth. Depending on their sizes, some particles will be exhaled, some will deposit in the upper airways (the nose, mouth and bronchial tree), and some will deposit in the deep lungs. Most particles larger than a few micrometres (µm) in diameter are filtered out in the upper airways and so do not reach the deep lungs: the nose is quite an effective filter. (One µm is one-thousandth of a millimetre. The cells that make up the body are typically about 10 µm across).
Most particles that deposit in the upper airways are trapped in mucus that moves to the throat and are swallowed within a few hours. Most particles that deposit in the deep lungs are quickly captured by mobile cells called macrophages, rather similar to white blood cells. They may move the particles to the bronchial tree, to be carried away in mucus and swallowed, but this is a slow process, and some particles may remain in the lungs for years.
A very small fraction of particles deposited in the lungs will be transferred to lymph nodes, where they would probably remain if they did not dissolve. However, whether in lungs or lymph nodes, uranium oxide particles will gradually dissolve, and the dissolved uranium will be absorbed into the blood. Even materials generally regarded as ‘insoluble’ will generally dissolve to some extent in the lungs: particles small enough to deposit there have a large surface area per unit mass for the liquids inside cells to work on.
It is generally found that when dusts are inhaled and deposit in the lungs, a fraction of the material dissolves rapidly and the rest at a fairly steady rate. Tests have been carried out on DU oxides which simulated dissolution in the lungs. These showed that for the particles formed when lumps of DU are heated in a fire, a few percent dissolves rapidly, but the rest very slowly. For the particles formed when a DU penetrator impacts on armour plate, a larger fraction, about 25%, dissolves quickly.
Other tests have shown that in both situations, the particles consist mostly of 2 uranium oxides (U3O8, with some UO2) both of which are relatively insoluble. Experiments carried out on industrial forms of these oxides indicate a long-term dissolution rate in the lungs of the order of 0.1% per day.
When uranium compounds are ingested, uranium is not readily absorbed into blood from the gut. Even for soluble forms of uranium only a few percent is absorbed (2% is usually assumed for radiation protection purposes). For the uranium oxides formed from DU impacts or fires, the fraction is likely to be much less. For relatively insoluble compounds like the 2 oxides above, in workplaces, 0.2% is usually assumed.
Most of the uranium absorbed into blood is rapidly excreted, mainly in urine. About 65% is excreted during the first day, another 10% during the rest of the first week. There is a continuing slow excretion, about 0.002% of the original uptake to blood per day after a year. That is why measurements are often made on urine to estimate the amount of uranium in the body.
The uranium that is not rapidly excreted deposits in various organs. In particular, about 10% deposits in the kidneys. Since the kidneys are relatively small (about 300 g in an adult), the concentration will be higher than in other organs. However, most of the uranium deposited in the kidneys does not stay for long. By 3 months, the amount retained is only about 0.1% of the original uptake to blood. About another 15% deposits in bone, but since the mass (5000 g) is much greater than that of the kidneys, the concentration is lower. Uranium does stay much longer in the bone, so there will still be a few percent left after 5 years, and about 1% after 25 years.
How is DU harmful?
In sufficient amounts, DU can be harmful because of its chemical toxicity. Like mercury, cadmium, and other heavy-metal ions, excess uranyl ions depress renal function. High concentrations in the kidney can cause damage and in extreme cases renal failure.
Furthermore, since DU is mildly radioactive, once inside the body it irradiates the organs. The main dose to the body organs will arise from the energy deposited in them from the emissions of the alpha particles. It is known that high doses of radiation can cause cancer. It is generally assumed for radiological protection purposes, that low doses of radiation can also cause cancer, but the lower the dose, the smaller the risk.
How do we know how harmful DU is?
There is a lot of information available already. Different isotopes of uranium have exactly the same chemical and biological behaviour, which is why chemical methods cannot be used to separate them to produce enriched uranium. Therefore the chemical toxicity of DU is the same as that of natural uranium. The radiological toxicity of DU is lower than that of natural uranium, because the specific activity is lower. When uranium went into large-scale production to produce reactor fuel, the possible chemical and radiological hazards were recognised. Animal experiments were carried out to investigate them. These experiments (mostly carried out many years ago) showed that if the exposure was high enough, the most likely effect was damage to the kidneys.
Estimates of the risks associated with exposure to ionising radiation are based mainly on studies of people who were exposed to high levels of radiation. The most important study is that of the survivors of the atom bomb attacks on Japan, because this is a large group, including all ages, a wide range of doses, and the whole body was irradiated. Furthermore, the health of these survivors has been studied over several decades. However, studies on various other groups of patients and workers, and results of animal experiments, are also used in assessing radiation risks. These include internal as well as external exposures. In particular, bone cancers were seen in workers who ingested large amounts of radium while applying luminous paint to dials in the early part of the 20th century.
Radium deposits in bone in a similar way to uranium, but has a far higher specific activity, and so ingestion of relatively small amounts can give high doses to bone. Using all this information, the risk of cancer from any radiation exposure (external or internal) is estimated from the amount and type of radiation each organ receives (per unit mass). Excess radiation-induced cancers cannot be seen at very low doses either in human studies or animal experiments, because the excess at low doses is small, and the same types of cancers occur naturally.
For radiation protection purposes it is generally assumed that the risk of cancer is proportional to the radiation dose: if the dose is halved, the risk is halved. Some scientists believe that there is a threshold for radiation effects, partly because life evolved in a radioactive environment, and so it is reasonable to expect that at low doses the body would repair any radiation damage. Public Health England (PHE), however, supports use of the assumption that all radiation doses, however small, carry some additional risk, which is proportional to dose.
An exception to the standard dosimetric approach to assessing radiation risks is made in the case of radon, a radioactive gas, which for most of the population gives rise to about half the dose from natural background radiation. A clear excess of lung cancers, which increases with increasing exposure to radon, is seen in groups of miners who were exposed to high levels of radon.
Risks from radon are based on the excess lung cancers in these miners, because the comparison is more direct than the standard approach, which predicts rather more cancers than are seen in the miners, ie it seems to somewhat overestimate the risk in this case. Risks from radon at lower levels are again based on the assumption that the risk is proportional to the exposure.
Many thousands of workers have also been exposed to uranium compounds over many years, through the processing of uranium from the ore to the production of fuel elements. Studies have been carried out on the health of such workers. While some studies have reported excesses of cancers, unlike the miners, no clear excess of any cancer related to increased exposure has been demonstrated. The only clear finding is a ‘healthy worker effect’; mortality is lower than in the general population. This is expected in such workforces, because of selection for employment, and the benefits of a regular income.
Are people naturally exposed to uranium?
Chemical compounds of uranium are found naturally, in trace amounts, in air, water, rock, soil, and materials made from natural substances. Small amounts are consumed and inhaled by everyone every day. In the UK the average daily consumption is about 3 micrograms (1 microgram (µg) = 0.000001 g) although it does depend on what people eat and drink. In some parts of the world the natural uranium consumption is higher than in the UK because of the underlying rock is rich in uranium. Consumption in parts of Canada can be hundreds of micrograms per day. It is estimated that the average person worldwide inhales 0.5 µg (14 mBq) and ingests 700 µg (18 Bq) each year in food and water.
What are the safe limits for DU inside the body?
Regarding the chemical toxicity, the most susceptible organ is considered to be the kidneys. In many countries, current occupational exposure limits for soluble uranium compounds are related to a maximum concentration of 3 µg of uranium per gram of kidney tissue. Any effects caused by exposure of the kidneys at these levels are considered to be minor and transient.
Current practices, based on these limits, appear to protect workers in the uranium industry adequately. In order to ensure that this kidney concentration is not exceeded in the UK, Health and Safety Executive regulations restrict long-term (8 hour) workplace air concentrations of soluble uranium to 0.2 mg per cubic metre and short-term (15 minute) to 0.6 mg per cubic metre.
It is more difficult to define a safe limit for radiation exposure since the risk of developing a cancer is assumed to be proportional to the dose received. Limits for radiation exposure are recommended by the International Commission on Radiological Protection (ICRP) and have been adopted by the European Union. The annual dose limit for a member of the public is 1 mSv, while the corresponding limit for a radiation worker is 20 mSv. The additional risk of fatal cancer associated with a dose of 1 mSv is assumed to be about 1 in 20,000. This small increase in lifetime risk should be seen in the context of around 1 in 4 people who die from cancer in the UK.
How much DU can someone be exposed to before the limits are reached?
This depends on the route of intake into the body, and on various assumptions about the size of the aerosol and solubility in the lungs and gut. For insoluble compounds, the material will tend to remain in the lungs for longer, and so the principal damage would be irradiation of the lungs. For more soluble material, the DU would be absorbed more quickly from the lungs into the blood stream where about 10% of it would initially concentrate in the kidneys.
The following table shows how much would have to be inhaled or ingested to lead to a dose of 1 mSv (radiation dose limit) or alternatively to lead to a kidney concentration of 3 µg per gram of kidney (chemical toxicity limit). These values have been calculated with the biokinetic models currently recommended by the ICRP.
|Route of intake||Intake (mass) leading to a kidney concentration of 3 µg per gram||Intake (mass) leading to a dose of 1 mSv|
|inhalation of reference ‘moderately soluble’ aerosol||230 mg||32 mg|
|inhalation of a reference ‘insoluble’ aerosol||7,400 mg||11 mg|
|ingestion of a reference ‘moderately soluble’ DU compound||400 mg||1,500 mg|
|ingestion of a reference ‘insoluble’ DU compound||4,000 mg||8,800 mg|
In order to express these amounts in becquerels, it should be noted that 1 mg of DU corresponds to about 15 Bq. It should also be borne in mind that the amounts required to give a kidney concentration of 3 µg per gram would be larger if the intake was given over a longer period of time since it would give the kidneys more time to excrete the DU. It can be deduced from the table that, for ingestion of DU, the chemical toxicity limit of 3 µg per gram of kidney tissue needs a smaller intake than the radiological limit (for a member of the public) of 1 mSv. For inhalation of a DU aerosol, the reverse is the case.
How can people be tested for exposure to DU?
Several nations and aid agencies have tested personnel who served in the Balkans. In 2001 the Ministry of Defence (MOD) in the UK announced that a programme of testing veterans from the Balkans would be started, and that tests would also be available to servicemen who fought in the Gulf War during 1991.
After inhalation of a DU aerosol, a fraction of the DU will be absorbed to blood from the lungs at a rate which depends on the solubility of the DU compound, insoluble compounds tending to remain in the lungs for longer. On the other hand, ingested DU will tend to pass straight through the gastrointestinal system and be excreted in faeces, although a small fraction (probably less than 2%) will be absorbed across the lining of the gut wall to blood. DU reaching the blood will circulate around the body organs, but most of it will be excreted in urine. The remaining fraction will tend to concentrate in kidneys and to a lesser extent in bone and other soft tissues. The body will, however, continue to excrete DU for many years, although in increasingly small amounts.
Measurements can be made of DU in the lungs by external counting (whole body monitoring) using specialised equipment. If there is more than a few milligrams of DU in the lungs, its presence can be detected with such equipment. This technique is most useful if measurements can be made soon after the exposure took place. However, for exposures taking place years previously, only a small fraction of the amount initially inhaled remains in the lungs, and so this type of measurement is less useful.
Measurement of uranium excreted in urine at known times after the exposure is a potentially more sensitive method for determining the amount of DU inhaled. However, uncertainties in the assessed intake can be quite large, because many assumptions concerning the aerosol size, solubility, and rates of movement around the body must be made. Another problem is that everyone excretes uranium in their urine because of the ingestion of naturally-occurring uranium in food and drink. Typically, an individual may excrete, depending on the dietary intake, between 0.001 µg and 0.05 µg of uranium in urine each day, although some may excrete much larger amounts, usually as a result of a high concentration of uranium in drinking water.
Up to about a year after inhalation, it may well be possible to show that the dose from inhalation of any DU is less than 1 mSv, simply on the basis of the total amount of uranium in urine (ie on the assumption that all the uranium present resulted from inhalation of DU). At later times, however, the amount of DU present in urine could well be much less than the amount of naturally-occurring uranium, and such an assumption would result in a large overestimate of intake and dose. For instance, an intake of 10 mg of DU by inhalation might give rise to about 0.003 µg in a daily urine sample 10 years after the exposure. To assess the intake of DU, it is therefore necessary to measure the uranium-235:uranium-238 isotopic ratio to determine the fraction of the measured uranium that is DU. Specialised mass spectrometric techniques, such as thermal ionisation mass spectrometry (TIMS) or high resolution inductively coupled plasma mass spectrometry (HRICPMS) have this capability, and can measure amounts of DU in a daily urine sample as low as 0.001 µg (approximately).
The following values for lung retention and daily urinary excretion rates (at different times after intake) have been calculated with the latest ICRP biokinetic models, following an inhalation of 1 mg of a DU aerosol.
|Time||Reference ‘moderately soluble’ aerosol - amount in lungs (mg)||Reference ‘moderately soluble’ aerosol - daily urinary excretion rate (mg per day)||Reference ‘insoluble’ aerosol - amount in lungs (mg)||Reference ‘insoluble’ aerosol - daily urinary excretion rate (mg per day)|
A similar calculation has been performed for the daily urinary excretion rate (mg per day) following ingestion of 1 mg of DU.
|Time||Reference ‘moderately soluble’ aerosol||Reference ‘insoluble’ aerosol|
Information on the test for uranium isotopes in urine that has been developed by the independent Depleted Uranium Oversight Board.
Is it likely that anyone could breathe enough DU to do any harm?
Not very likely. DU is a low specific activity material, so a large mass has to enter the body to give even a moderate radiation dose. In this context, others have pointed out that to inhale 1 g of any dust in a short time is almost impossible. Even over a long time it is not easy. An air concentration of 10 mg per cubic metre is regarded as noticeably and unpleasantly ‘dusty’. An adult breathes about 1 cubic metre an hour during normal daytime activities, so would have to inhale dusty air continuously 8 hours a day for nearly 2 weeks to inhale 1 g. The dust would have to be very contaminated to be even 10% DU. Generally, away from the immediate site of a DU weapon attack, the concentration in dust will be far less. Hence in almost any normal situation it is unlikely that anyone would inhale even 100 mg of DU. The radiation dose from this would be up to about 10 mSv, similar to the average annual dose from radon in parts of the UK. Thus, even if many people inhaled that amount (which is even more unlikely), the effects would be too small to observe.
With regard to chemical effects, the occupational exposure level is 0.2 mg of soluble uranium per cubic metre (see ‘What are the safe limits for depleted uranium inside the body?’ above). It is unlikely that more than 25% of the DU is soluble or that dust to which people are exposed is more than 10% DU. On this basis 0.2 mg per cubic metre corresponds to 8 mg dust per cubic metre, which people would not normally willingly tolerate for long.
What are the likely symptoms for over-exposure to DU?
DU has 2 different effects on the body, chemical and radio toxicity.
Uranium (whether depleted or natural) is a heavy metal and is chemically toxic in large amounts. We all consume some uranium with food and water, and no harmful effects at this level of exposure have been reported. However, scientists are studying people in different regions carefully to find out if there are effects of natural uranium in the diet. In high doses uranium can damage the kidneys causing renal failure. This would manifest through a number of symptoms including nausea, tiredness and anaemia. Kidney function can be tested by blood and urine tests.
Uranium is also mildly radioactive although depleted uranium is less radioactive than natural uranium. DU weapons could not expose people to enough radiation to produce radiation sickness. There remains the possibility that exposure to DU could increase the risk of cancer later in life. This needs to be set against the background risk of fatal cancer of 1 in 4. The additional risk due to exposure to DU weapons is unlikely to increase this underlying cancer risk significantly. In other words, it seems unlikely that any excess would be observed in an exposed population.
When DU is inhaled in an insoluble or moderately soluble form, the highest radiation dose (to an organ in which it is known that radiation can induce cancer at high doses) is to the lungs, and after that the bone. The dose to the red bone marrow, which is considered to be the target organ for the induction of leukaemia, is about 100 times smaller than that to the lungs. Since the lungs and red bone marrow are considered to be equally radiosensitive, one would expect fewer leukaemias than lung cancers.
In groups of people where radiation induced leukaemias have been seen, notably the Japanese atomic bomb survivors and patients who received radiotherapy for other conditions, several years were needed between exposure to radiation and clinical detection of leukaemia.
Where can I find out more about DU?
There is a great deal of information available on the Internet. A number of useful links are provided below; however it must be recognised that PHE is not responsible for the content of external websites. These links are provided for information, not as recommendations.
Some of the sites provide very detailed technical information, and some are more up to date than others. In addition to providing factual information, some sites express opinions about the toxicity of uranium and DU and the hazards associated with the use of DU. Such opinions cover a wide range and some are more soundly based than others.
Please note that some of these links are to pages in portable document format (PDF).
The US Government Office of the Special Assistant to the Secretary of Defense for Gulf War Illnesses (OSAGWI) maintains a site partly to provide information for US veterans. It includes some comprehensive reports, in particular an environmental exposure report which addresses the exposures that soldiers and other personnel might have received in the Gulf War, and has a great deal of background information.
The last update of the Environment Exposure Report, Depleted Uranium in the Gulf (II) (December 2000. There is also a review of information on uranium toxicology (A Review of the Scientific Literature as it Pertains to Gulf War Illnesses. Volume 7, Depleted Uranium).
A critical review (2000) of epidemiological studies on uranium workers by the US Institute of Medicine (Gulf War and Health: Volume 1. Depleted Uranium, Pyridostigmine Bromide, Sarin, and Vaccines).
The IAEA conducted 2 radiological assessments in Kuwait (Radiological Conditions in Areas of Kuwait with Residues of Depleted Uranium - Report by an international group of experts) and in southern parts of Iraq (Radiological Conditions in Areas of southern Iraq with Residues of Depleted Uranium - Report by an international group of experts). The IAEA concluded that on the basis of the measurements carried out at the sites investigated in Kuwait and southern Iraq, DU does not pose a radiological hazard to the population of these countries.
With regard to Bosnia and Kosovo, the United Nations Environment Programme (UNEP) set up in 2000 a Balkans Task Force, investigating the environmental consequences of the 1999 conflict in Kosovo.
The Balkans Task Force produced a desk assessment of potential effects on human health and the environment arising from possible use of depleted uranium. Between 1999 and 2003, UNEP assembled teams of international experts to carry out measurements and radiological assessments at sites targeted with DU in Kosovo, Serbia and Montenegro, and Bosnia and Herzegovina.
The Royal Society has published 2 reports on the health hazards of depleted uranium in munitions. Part I, published in May 2001, deals with the amounts of DU to which soldiers could be exposed on the battlefield, the risks from radiation and what is known from epidemiological studies, especially those on uranium workers. Part II, published in March 2002, considers the chemical toxicity of uranium, the environmental impact and some responses to part I of the report. Both reports are available from the Royal Society website (enter ‘depleted uranium’ in the search window).
The World Health Organization has also conducted a review of the scientific literature from which health risks could be assessed for various DU exposure situations. Read the executive summary of this report.
Information on the test for uranium isotopes in urine that has been developed by the independent Depleted Uranium Oversight Board.