|Fact sheet No 257: Depleted Uranium - January 2001 (WHO, 2001, 5 p.)|
Leukaemia occurs in adult populations in the world at an incidence rate of about 50 cases per million per year for the age group range of 20-45 years. The exact rate of leukaemia will vary depending on the country. While exposure to DU could theoretically lead to a risk of cancer, this seems unlikely to have occurred among military personnel in the Balkans for the following reasons:
· Generally several years (at least two to five years) are needed between exposure to ionizing radiation and clinical detection of radiation-induced leukaemia.
· While ionizing radiation exposure is known to cause leukaemia, the risk is proportional to the level of radiation exposure. As is illustrated from previous experience, about half the leukaemia cases among survivors of the atomic bomb on Hiroshima and Nagasaki are attributable to gamma-ray and neutron exposure from the bombing. In contrast, about 10% of leukaemia deaths in a large multinational study of nuclear industry workers are thought to be attributable to external gamma-ray exposure. Furthermore, while a large increase in childhood thyroid cancer has been demonstrated 15 years after the Chernobyl nuclear reactor accident, as yet, no increase in leukaemia has been detected in populations environmentally exposed in the most contaminated territories.
· No radiation-related increases in leukaemia have been established in uranium miners or workers milling uranium metal for nuclear reactor fuel elements.
· In war zones, the inhalation and ingestion of DU contaminated dust, even under extreme conditions, and shortly after the impact of projectiles, as determined by the amount of dust that can be inhaled, has been calculated to result in a radiation exposure of less than about 10 millisieverts (mSv). This represents about half the annual dose limit for radiation workers. Such an exposure is thought to result only in a small proportional increase in the risk of leukaemia, of the order of 2% over the natural incidence.
While from the science it appears unlikely that an increased leukaemia risk related to DU exposure would be detectable among military personnel in the Balkans, the World Health Organization (WHO) does not have enough information on the exposure situations in the Gulf or Balkans to make firm conclusions. A detailed study is needed to determine the numbers of soldiers exposed, the amount of DU used, how much exists on the surface, how much is buried in the ground, what is the composition of fine to coarse particles, and whether or not the excess of leukaemia reported among military personnel is above the normal incidence. It is important that when studies of military personnel possibly exposed to DU are carried out, information on all possible risk factors (including other environmental exposures, etc.) for leukaemia are collected so that any possible cause of leukaemia is not missed.