Utarmat uran i ammunition, farligt?

Health aspects of DU

Depleted uranium is not classified as a dangerous substance radiologically, though it is a potential hazard in large quantities, beyond what could conceivably be breathed. Its emissions are very low, since the half-life of U-238 is the same as the age of the earth (4.5 billion years). There are no reputable reports of cancer or other negative health effects from radiation exposure to ingested or inhaled natural or depleted uranium, despite much study.

However, uranium does have a chemical toxicity about the same as that of lead, so inhaled fume or ingested oxide is considered a health hazard. Most uranium actually absorbed into the body is excreted within days, the balance being laid down in bone and kidneys. Its biological effect is principally kidney damage. WHO has set a Tolerable Daily Intake level for U of 0.6 microgram/kg body weight, orally. (This is about eight times our normal background intake from natural sources.) Standards for drinking water and concentrations in air are set accordingly.

Like most radionuclides, it is not known as a carcinogen, or to cause birth defects (from effects in utero) or to cause genetic mutations. Radiation from DU munitions depends on how long the uranium has been separated chemically from its decay products. If thorium-234 and protactinium-234 has built up through decay of U-238, these will give rise to some beta emissions. On this basis, DU is "weakly radioactive" with an activity of 39 kBq/g quoted (15 kBq/g if pure, compared with 25 kBq/g for pure natural uranium).

In 2001 the UN Environment Program examined the effects of nine tonnes of DU munitions having been used in Kosovo, checking the sites targeted by it. UNEP found no widespread contamination, no sign of contamination in water of the food chain and no correlation with reported ill-health in NATO peacekeepers. A two-year study by Sandia National Laboratories in USA reported in 2005 that consistent with earlier studies, reports of serious health risks from DU exposure during the 1991 Gulf War are not supported by medical statistics or by analysis.

Thus DU is clearly dangerous for people in vehicles which are military targets, but for anyone else - even in a war zone - there is little hazard. Ingestion or inhalation of uranium oxide dust resulting from the impact of DU munitions on their targets is the main possible exposure route. See also Appendix and WHO fact sheet on DU.

* In the kidneys, the proximal tubules (the main filtering component of the kidney) are considered to be the main site of potential damage from chemical toxicity of uranium. There is limited information from human studies indicating that the severity of effects on kidney function and the time taken for renal function to return to normal both increase with the level of uranium exposure.
* In a number of studies on uranium miners, an increased risk of lung cancer was demonstrated, but this has been attributed to exposure from radon decay products. Lung tissue damage is possible leading to a risk of lung cancer that increases with increasing radiation dose. However, because DU is only weakly radioactive, very large amounts of dust (on the order of grams) would have to be inhaled for the additional risk of lung cancer to be detectable in an exposed group. Risks for other radiation-induced cancers, including leukaemia, are considered to be very much lower than for lung cancer.
* Erythema (superficial inflammation of the skin) or other effects on the skin are unlikely to occur even if DU is held against the skin for long periods (weeks).
* No consistent or confirmed adverse chemical effects of uranium have been reported for the skeleton or liver.
* No reproductive or developmental effects have been reported in humans.
* Although uranium released from embedded fragments may accumulate in the central nervous system (CNS) tissue, and some animal and human studies are suggestive of effects on CNS function, it is difficult to draw firm conclusions from the few studies reported.