Talk:Depleted uranium/health
Health effects of DU are determined by factors such as the extent of exposure and whether it was internal or external. Three main pathways exist by which internalization of uranium may occur: inhalation, ingestion, and embedded fragments or shrapnel contamination. Properties such as phase (e.g. particulate or gaseous), oxidation state (e.g. metallic or ceramic), and the solubility of uranium and its compounds influence their absorption, distribution, translocation, elimination and the resulting toxicity. For example, metallic uranium is relatively non-toxic compared to hexavalent uranium(VI) compounds such as uranyl nitrate. (See «Gmelin Handbuch der anorganischen Chemiek» 8th edition, English translation, Gmelin Handbook of Inorganic Chemistry, vol. U-A7 (1982) pp. 300-322.)
Projectile munitions can cause substantial inhalation exposure risks.[1] Those risks have been associated with a number of health concerns, some of which are controversial.
Early scientific studies usually found no link between depleted uranium and cancer, and sometimes found no link with increases in the rate of birth defects, but newer studies have and offered explanation of birth defect links. There is no direct proof that uranium causes birth defects in humans, but it induces them in several other species of mammals, and human epidemiological evidence is consistent with increased risk of birth defects in the offspring of persons exposed to DU.[2]. Environmental groups and others have expressed concern about the health effects of depleted uranium[3], and there is significant debate over the matter. Some people have raised concerns about the use of this material, particularly in munitions, because of its proven mutagenicity [4], teratogenicity [5],[6] in mice, and neurotoxicity [7], and its suspected carcinogenic potential, because it remains radioactive for an exceedingly long time with a half-life of approximately 4.5 billion years; and because it is also toxic in a manner similar to lead and other heavy metals. The primary radiological hazards associated with this material are beta and alpha emissions, however the long half-life indicates that depleted uranium is only weakly radioactive. All isotopes and compounds of uranium are toxic. Such issues are of concern to civilians and troops operating in a theatre where DU is used, and to people who will live for several years afterward in such areas or breathing air or drinking water from these areas.[8]
Studies showing detrimental health effects have shown the following:
- Indications that DU passes into humans more easily than previously thought after battlefield use. (radioactive particles absorbed into the body are far more harmful than a similar background radiation level outside the body, due to their immediate proximity to delicate structures such as DNA, bone marrow and the like.) Pre-1993 military DU studies mainly evaluated external exposure only.[9][10]
- DU can disperse into the air and water, United Nations Environment Programme (UNEP) study [11] says in part:
- "The most important concern is the potential for future groundwater contamination by corroding penetrators (ammunition tips made out of DU). The munition tips recovered by the UNEP team had already decreased in mass by 10-15% in this way. This rapid corrosion speed underlines the importance of monitoring the water quality at the DU sites on an annual basis."
Because DU is a chemical toxicant heavy metal with nephrotoxic (kidney-damaging)[12], teratogenic (birth defect-causing)[13], and potentially carcinogenic[14] properties, there is a connection between uranium exposure and a variety of illnesses[15]. The chemical toxicological hazard posed by uranium dwarfs its radiological hazard because it is only weakly radioactive. In 2002, A.C. Miller, et al., of the U.S. Armed Forces Radiobiology Research Institute, found that the chemical generation of hydroxyl radicals by depleted uranium in vitro exceeds radiolytic generation by one million-fold[16]. Hydroxyl radicals damage DNA and other cellular structures, leading to cancer, immune system damage in white blood cells, birth defects in gonocytes (testes), and other serious health problems. (See Halliwell and Gutteridge, eds. (1999) Free Radicals in Biology and Medicine, 3rd ed., Oxford University Press.) In 2005, uranium metalworkers at a Bethlehem plant near Buffalo, New York, exposed to frequent occupational uranium inhalation risks, were found to have the same patterns of symptoms and illness as Gulf War Syndrome victims[17],[18].
A report written by an Irish petro-chemical engineer stated that in Iraq, the death rate per 1000 Iraqi children under 5 years of age increased from 2.3 in 1989 to 16.6 in 1993, and cases of lymphoblastic leukaemia more than quadrupled. (K. Rirchard (1998) Does Iraq's depleted uranium pose a health risk? The Lancet, Volume 351, Number 9103). I. Al-Sadoon, et al., writing in the Medical Journal of Basrah University, report a similar increase (see Table 1 here). However, Dr. Richard Guthrie, an expert in chemical warfare at Sussex University, has argued that a more likely cause for the increase in birth defects was the Iraqi Army’s use of teratogenic mustard agents.
Several sources have attributed the increase in the rate of birth defects in the children of Gulf War veterans and in Iraqis to depleted uranium inhalation exposure[19],[20]. A 2001 study of 15,000 February 1991 U.S. Gulf War combat veterans and 15,000 control veterans found that the Gulf War veterans were 1.8 (fathers) to 2.8 (mothers) times more likely to have children with birth defects[21]. In a study of U.K. troops, "Overall, the risk of any malformation among pregnancies reported by men was 50% higher in Gulf War Veterans (GWV) compared with Non-GWVs"[22].
Early studies of depleted uranium aerosol exposure assumed that uranium combustion product particles would quickly settle out of the air[23] and thus could not affect populations more than a few kilometers from target areas[24], and that such particles, if inhaled, would remain undissolved in the lung for a great length of time and thus could be detected in urine[25]. But those studies ignored uranium trioxide gas -- also known as uranyl oxide gas, or UO3(g) -- which is formed during uranium combustion (R.J. Ackermann, et al., "Free Energies of Formation of Gaseous Uranium, Molybdenum, and Tungsten Trioxides," Journal of Physical Chemistry, vol. 64 (1960) pp. 350-355, "gaseous monomeric uranium trioxide is the principal species produced by the reaction of U3O8 with oxygen." U3O8 being the dominant aerosol combustion product [26].) Uranyl ion contamination has been found on and around depleted uranium targets [27]. UO3 gas remains dissolved in the atmosphere for weeks, but as a monomolecular gas is absorbed immediately upon inhalation, leading to accumulation in tissues including gonocytes (testes [28]) and white blood cells [29], but virtually no residual presence in urine other than what might be present from coincident particulate exposure.
By contrast, other studies have shown that DU ammunition has no measurable detrimental health effects, either in the short or long term. The International Atomic Energy Agency reported in 2003 that, "based on credible scientific evidence, there is no proven link between DU exposure and increases in human cancers or other significant health or environmental impacts," although "Like other heavy metals, DU is potentially poisonous. In sufficient amounts, if DU is ingested or inhaled it can be harmful because of its chemical toxicity. High concentration could cause kidney damage." [30]
In October, 1992, an El Al Boeing 747-F cargo aircraft crashed in a suburb of Amsterdam. After reports of local residents and rescue workers complaining of heath issues related to the release of depleted uranium used as counterbalance in the plane, authorities began an epidemiological study in 2000 of those believed to be effected by the accident. The study concluded that because exposure levels were so low, it was highly improbable that exposure to depleted uranium was the cause of the reported health complaints.
The primary health impact of depleted uranium relates to its chemical toxicity as a heavy metal rather than to its radioactivity, which is relatively low. In fact, there is some evidence to suggest that low-level radiation, such as that from uranium, is beneficial to human beings. [31] [32] [33] As with any heavy metal, the overall hazard depends on the amount of exposure.
Any connection between Gulf War Syndrome and depleted uranium exposure is purely speculative, because all studies claiming such a link fail to demonstrate that those afflicted by the illness have increased uranium in their bodies, in comparison to those who also served in the Gulf and did not get the illness. In fact, one study shows that just the opposite is true. A number of soldiers were identified with DU fragments in their bodies following friendly fire incidents. There was no increase in health problems in this group, despite the relatively high amount of uranium in their bodies and urine. [34]
A two year study headed by Sandia National Laboratories’ Al Marshall analyized potential health effects associated with accidental exposure to depleted uranium during the 1991 Gulf War. Marshall’s study concluded that the reports of serious health risks from DU exposure are not supported by veteran medical statistics and were consistent with earlier studies form Los Alamos and the New England Journal of Medicine [35].
There is no proof that battlefield exposure to depleted uranium has caused harm, except to those targeted by the munitions. It has, on the other hand, been proven to save the lives of soldiers using it. There is a published report of an American M1 tank that was shot at close range by 3 different Iraqi T-72 tanks. The armor of the American tank, which was partially made of depleted uranium, protected the American crew from all 3 Iraqi shots. Then the American crew was able to use depleted uranium sabot rounds to destroy all 3 tanks that had shot it. [36]
Further evidence against the role of DU used in combat in causing human illness comes from another war zone. If DU caused health problems in the Gulf War zone, it would be expected to do so in other warzones, but this has not proven true. In the Balkans, "independent investigations by the World Health Organization, European Commission, European Parliament, United Nations Environment Programme, United Kingdom Royal Society, and the Health Council of the Netherlands have all have discounted any association between depleted uranium and leukemia or other medical problems among Balkans veterans." [37]