There is a lot of misinformation out there on the internet
s regarding uranium-238, or "depleted uranium"; I've seen all sorts of comments on other forums, from "you can build a nuke with it!" to "if a woman has sex with a soldier who's been exposed to depleted uranium, she'll get endometriosis" (yes, I really did see that).
To date, it is not known conclusively what the effects of long-term exposure to depleted uranium are. However, the few studies that have been done indicate that depleted uranium is toxic, and hint that long-term exposure can most likely result in significant health problems.
So, without further ado, I'm going to try to clear up at least some of the misconceptions about depleted uranium.
What is depleted uranium?
Natural uranium is mostly a mixture of 0.7% uranium-235, and 99.3% uranium-238. When uranium is depleted to remove the U-235 (for bombs or nuclear reactors), what's left behind is the slightly less radioactive U-238, also known as "depleted" uranium, which is not fissionable.
What is the military application of U-238, and how does it spread?
Since U-238 is very dense (1.7 times the density of lead), it is used in armor-penetrating projectiles. U-238 is naturally pyrophoric, i.e. it ignites on impact, which not only enhances its armor piercing ability, but also creates an aerosol of U-238 particles, which can be inhaled. An example of a U-238 round is the PGU-14/B API Armor Piercing Incendiary (30mm ammunition), which contains 0.66 lbs of U-238.
Where, and how often, have U-238 munitions been used?
U-238 munitions have been used extensively in both Gulf War I and the current Iraq war, complete with warnings:
In the first Gulf War, US forces used 320 tons of DU, 80 percent of it fired by A-10 aircraft. Some estimates suggest 1,000 tons or more of DU was used in the current war. But the Pentagon disclosure Wednesday that about 75 tons of A-10 DU bullets were used points to a smaller overall DU tonnage in Iraq this time.
US military guidelines developed after the first Gulf War - which have since been considerably eased - required any soldier coming within 50 yards of a tank struck with DU to wear a gas mask and full protective suit. Today, soldiers say they have been told to steer clear of any DU.
"If a [tank] was taken out by depleted uranium, there may be oxide that you don't want to inhale. We want to minimize any exposure, at least to the lowest level possible," Dr. Michael Kilpatrick, a top Pentagon health official told journalists on March 14, just days before the war began. "If somebody needs to go into a tank that's been hit with depleted uranium, a dust mask, a handkerchief is adequate to protect them - washing their hands afterwards."
Not everyone on the battlefield may be as well versed in handling DU, Dr. Kilpatrick said, noting that his greater concern is DU's chemical toxicity, not its radioactivity: "What we worry about like lead in paint in housing areas - children picking it up and eating it or licking it - getting it on their hands and ingesting it."
In the US, stringent NRC rules govern any handling of DU, which can legally only be disposed of in low-level radioactive waste dumps. The US military holds more than a dozen NRC licenses to work with it.
Please note that this article was written in May 2003, with the assumption that the war was "over".
Why is U-238 dangerous?
As mentioned in the CSM article, the primary concern is U-238's chemical toxicity, the primary result of which is kidney damage, as outlined in a report by the Royal Society.
Also, a scientist at the Armed Forces Radiobiology Research Institute in Maryland published a study that showed that U-238 is genotoxic, emphasizing that radioactivity is not as much a concern as chemical toxicity. The abstract for her paper is here, but the New Scientist has a translation for non-nerds:
Uranium is "genotoxic". It chemically alters DNA, switching on genes that would otherwise not be expressed. The fear is that the resulting abnormally high activity in cells could be a precursor to tumour growth...
...Miller has found one way this may happen. She has discovered the first direct evidence that radiation from DU damages chromosomes within cultured cells. The chromosomes break, and the fragments reform in a way that results in abnormal joins (Military Medicine, vol 167, p 120). Both the breaks and the joins are commonly found in tumour cells.
More crucially, she has recently found that DU radiation increases gene activity in cultured cells at doses of DU not known to cause chemical toxicity (Molecular and Cellular Biochemistry, in press). The possible consequences are made all the more uncertain because no one knows if genes switched on by DU radiation enhance the damage caused by genes switched on by DU's toxic effects, or vice versa. "I think that we assumed that we knew everything that we needed to know about uranium," says Miller. "This is something we have to consider now when we think about risk estimates."
Iraqi doctors are suspicious, but the U.S. says U-238 is safe.
Although no studies have been performed to indicate that U-238 causes cancer or birth defects, twelve years after Gulf War I, Iraqi doctors have seen a significant increase in cancer and birth defects in Iraq. The U.S. has repeatedly denied that U-238 munitions pose any health risk, either to soldiers or civilians, despite the recommendations of the Royal Academy. The U.S. refuses to clean up the mess...
...an irresponsible attitude toward the toxic legacy of a war based upon a lie.