The section addresses the issue of the radiation effects of uranium. Unlike the situation with the chemical effects, the amount of radiation to which the body is exposed is different for the various forms of uranium. Natural uranium is only mildly radioactive, and depleted uranium is 40% less radioactive. However, disease due to radiation effects of uranium, whether natural or depleted, has not been observed in either animals or humans. Therefore, this section focuses more on radiation exposure than actual disease. Although the radiation dose from a particular uranium exposure can be estimated, it is small. Because disease from the radiation has not been observed, the radiation effect is usually less of a concern than the chemical effect: natural and depleted uranium are much more likely to be chemical than radiation hazards.
Q1:
What types of radiation are associated with DU?
A:
As they decay, uranium atoms, whether natural or depleted, give off small amounts of radiation, like sources of natural background radiation in the environment. DU and its decay products give off radiation that could potentially cause exposure inside the body as well as externally. While DU gives off alpha particles, the decay products give off beta and gamma particles as they decay even more. However, the alpha radiation does not penetrate the outer, dead layer of skin, and so uranium must be first taken into the body for alpha particles to be a concern. Beta radiation is screened out by normal military clothing, but could be a concern if uranium were first taken into the body, or protective clothing (such as gloves) was not worn. Gamma radiation, which is penetrating, must be considered even without internal exposure to uranium, but the doses of it from DU are small. Research indicates that exposures to alpha and beta particles would be below occupational guidelines.
Q2:
Can exposure to DU cause cancer?
A:
There is no solid evidence from human studies that internal uranium exposure is associated with an increased cancer risk. Although cancer is a well known effect of ionizing radiation exposure, it has never been associated with exposure to uranium. A small fraction of the uranium taken into the body becomes deposited in the skeleton, but scientific observations have not shown any increase in bone cancer in persons exposed to uranium, including enriched uranium, which is about 100 times as radioactive as DU.
People are constantly bombarded by radiation from many sources. Radiation comes from space, from radioactive materials in the soil, including natural uranium, and also radioactive isotopes of other more common metals, such as potassium. There is radiation in the air, and the food that we eat. In addition, people receive radiation from routine x-rays to diagnose disease, or with radiation therapy to treat disease. In some areas of the world, people are exposed to levels of background radiation that is three times higher than in the U.S. These people, exposed only to high levels of background radiation, have some alterations in chromosomes due to the higher radiation exposures, but do not show any increase in rates of cancer or other diseases that may be linked to radiation exposure.
Q3:
Has radiation risk in DU-armored vehicles been evaluated?
A:
There is no solid evidence from human studies that internal uranium exposure is associated with an increased cancer risk. Although cancer is a well known effect of ionizing radiation exposure, it has never been associated with exposure to uranium. A small fraction of the uranium taken into the body becomes deposited in the skeleton, but scientific observations have not shown any increase in bone cancer in persons exposed to uranium, including enriched uranium, which is about 100 times as radioactive as DU.
People are constantly bombarded by radiation from many sources. Radiation comes from space, from radioactive materials in the soil, including natural uranium, and also radioactive isotopes of other more common metals, such as potassium. There is radiation in the air, and the food that we eat. In addition, people receive radiation from routine x-rays to diagnose disease, or with radiation therapy to treat disease. In some areas of the world, people are exposed to levels of background radiation that is three times higher than in the U.S. These people, exposed only to high levels of background radiation, have some alterations in chromosomes due to the higher radiation exposures, but do not show any increase in rates of cancer or other diseases that may be linked to radiation exposure.
Q4:
How significant is the radiation risk to civilians residing in areas of former conflict?
A:
Similar mathematical models to those used in the Capstone Study were used by other governments and organizations, including the World Health Organization and the United Nations Environmental Program, to conclude that DU remaining in former areas of conflict did not create a current environmental hazard to the occupants of those areas. Those researchers examined the risk created by DU particles in the soil that could be resuspended in the air through the action of the wind or human activities. Many of these reports may be accessed directly through the section on Environmental Effects and Exposures.