Depleted uranium: weapon of war.

AuthorMontague, Peter
PositionBiodevastation

Uranium is a naturally occurring element that is both weakly radioactive and a toxic heavy metal. Naturally occurring uranium contains two main radioactive isotopes: U-238 (99.3%), and U-235 (0.7%). When uranium is "enriched" to make an A-bomb (which requires lots of U-235), the leftover "depleted uranium" (DU) is 99.8% U-238 and retains about 60% of the radioactivity that was present in the original natural uranium.[1, pg. 3]

Depleted uranium is created by "uranium enrichment" plants that process natural uranium to extract U-235, but those same plants also may process spent nuclear fuel from nuclear power reactors. For this reason, some DU is known to be contaminated with very low levels of some of the most dangerous radioactive substances known to science: Plutonium-238, Plutonium-239, Plutonium-240, Americium-241, Neptunium-237 and Technicium-99.[1, pg. 6]

Radioactive decay is a natural process. Radioactive elements spontaneously emit energetic particles or rays, and in the process they change from one element into another. When U-238 spontaneously undergoes radioactive decay, it emits alpha particles and turns into Thorium-234. You can think of an alpha particle as something like a tiny cannon ball--it does not travel very far (a few centimeters in air), but if it hits a living cell, the but if it hits a living cell, the damage can be enormous. Sometimes cells damaged by alpha particles die immediately, but sometimes they start to multiply uncontrollably, causing cancer. The International Agency for Research on Cancer (IARC) has identified "internally deposited radionuclides that emit alpha particles" as Group I carcinogens, meaning substances known to cause cancer in humans.[1, pg. 85]

So, DU's alpha particles won't penetrate the outermost (dead) layer of your skin, but if you get DU inside you--say, in your lungs--it can have deadly consequences. Several studies of workers in uranium enrichment plants show that they get lung cancer at higher-than-normal rates.[1, pg. 86]

The half-life of U-238 is 4.5 billion years, which tells us that it does not decay rapidly and therefore that it does not emit many alpha particles per second. However, "many" is a relative term. In absolute numbers, a microgram of DU (a millionth of a gram, and there are 28 grams in an ounce) will emit slightly more than 12 alpha particles per second or 390 million alpha particles each year.[1, pg. 6] So one microgram of DU lodged in your lungs will have more than a million opportunities each day to start a cancer growing in your cells. Obviously, the hazard is greater for children because they have a longer lifetime ahead of them during which alpha particles will have an opportunity to start a cancer, plus they are very likely more sensitive to harm than adults because they are growing, so more of their cells are dividing.

In recent decades, as we have manufactured more atomic bombs and therefore more depleted uranium, there has been growing pressure to find new uses for our huge stockpile of depleted uranium.[1, pg. 26]

Because it is almost twice as dense as lead and not very radioactive, DU...

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