Mention depleted uranium to an Iraqi doctor, and you will be told of the thousands of deaths and the tenfold increase in leukemia cancers in Iraq. However, ask a Pentagon official, and you will be told that depleted uranium has no negative health effects, and that it, in fact, has saved American lives.

The controversy resides around the depleted uranium (DU) bullets and shells used by the U.S. and British armed forces. Munitions with depleted uranium are favored because of DU's heavy weight and hardness, making it possible to pierce through heavy tank armor. However, DU is both radioactive and chemically toxic to the human body. This means that soldiers, civilians and the environment are exposed to this possibly harmful material. Thus, the question arises: is the use of DU justified? Today, the debate is very polarized, but unfortunately there are few accurate and comprehensive studies on the topic. Consequently, each side claims that they are correct. In actuality, the truth about depleted uranium probably lies somewhere between both sides.

Figure 1: One of the depleted uranium shells found in Bosnia-Herzogovinia by the U.N. PCAU Team.

Chemical Properties and Exposure to DU
Depleted uranium is a by-product of the uranium enrichment process used to create nuclear reactor fuel. Natural uranium contains a mixture of ²³⁸U, ²³⁵U and ²³⁴U. The latter two are the most radioactive of these isotopes, and thus most suited for reactor use. As a by-product of the enrichment process, DU contains approximately one third of the original ²³⁵U (0.2–0.3% by weight). This makes DU 40% less radioactive than natural uranium; by comparison, DU is 10 million times less radioactive than the compound used in home fire detectors, americium-241.

While DU is radioactive, this radioactivity is generally not considered to be of great harm, unless DU fragments are embedded in the body. Much of the radiation is stopped by the skin and so radiation levels are usually below occupational standards set by the National Council on Radiation Protection and Measurement (NCRP). More specifically, the Department of Defense estimates that soldiers who directly work with DU rounds are exposed to the equivalent of one chest x-ray every 20–30 hours.

Of greater concern are the chemical aspects of DU, which are as harmful as natural uranium. Unfortunately, there is very little reliable human data on the chemical effects of DU used in the military. Much of our current knowledge is based on studies of the toxicity of uranium in animals. In addition, many of these studies used the uranyl ion, UO2 and UO3, not uranium metal.

In order for these chemical effects to be dangerous, however, the DU must enter the body. There are several pathways for internalization: inhalation, ingestion, and embedded fragments in the body. Of these, inhalation is the most common pathway for internalization because DU will ignite and burn into a fine cloud of dust upon hitting a hard target. This dust can then be inhaled by soldiers, settle and contaminate soil and groundwater, or, if the struck target is left on the battlefield, pose a health risk to local populations.

By inhaling DU dust, the particles are deposited along the respiratory tract and in the lungs. The DU is then incorporated in the blood, and much of this is then quickly fi ltered by the kidneys. This puts a large amount of stress on the kidney organs, and makes them more susceptible to failure. According to the Royal Society (a UK-based scientific organization), soldiers who inhale large amounts of DU on the battlefield (e.g., while cleaning up contaminated equipment or those who survive a DU attack) could suffer kidney failure "within days." In addition, animal studies have shown that DU can create long term problems such as cancer, nervous system problems, immune disorders, and reproductive effects.

Measured Effects of DU
Since the first Gulf War, the Department of Defense (DoD) and Veterans Administration (VA) have followed approximately 70 soldiers who were directly exposed to DU. These studies claim that no harmful effects directly linked with DU. However, several of the monitored veterans have developed cancers, including a highly uncommon lymphatic cancer. Some independent studies have found strong correlations between DU intake and severe health effects, while others (including studies by the EU, UN, and WHO) refute these claims.

Many of these studies have serious flaws. The VA study, for example, tracks only a small fraction of the nearly 900 veterans who were exposed to DU. Other studies can often be faulted for assuming that DU was the only factor in veteran's health — in fact, soldiers are exposed to many chemicals, antidotes, trauma and other health hazards.

Environmentalists are also concerned with the impact of DU on the environment. Certainly several hundred tons of radioactive material cannot be good for the water, air and soil quality. Regrettably, there is little information on this aspect. The most extensive studies have been carried out by the UN Post Conflict Assessment Unit (PCAU) in Kosovo and Bosnia-Herzegovina. The PCAU team found that the DU in those areas posed no significant risk to the environment; however the team also cautioned that long-term monitoring would be necessary to completely assess the risk. Also, as noted above, only 13 tons of DU were used in the Kosovo/Bosnia-Herzegovina area, compared with several hundred tons now in Iraq; no PCAU studies have been carried out in Iraq.

Finally, claims by Iraqi doctors and other anti-DU activists that DU has caused thousands of cancer deaths and other illnesses, while probably not entirely unfounded, have not been substantiated with scientific studies. For example, Iraqi studies do not consider other factors, such as malnutrition, the use of chemical weapons near civilian populations, etc. Clearly, these claims deserve to be investigated.

Conclusion
There are no definitive conclusions regarding the health and environmental risks of depleted uranium. More testing and long-term studies are needed, especially in high-risk areas such as the Persian Gulf. Additionally, if the military continues to use DU, it should carry out comprehensive medical testing of all veterans exposed, and gather more data on the possible long-term affects of depleted uranium in areas where it is present. While the debate and uncertainty about DU is likely to continue, studies which address both the complexities of DU contamination and the long-term affects it may have on populations in war-torn areas will serve to clarify ambiguities and make consensus a more tenable possibility.