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ranium, in its many forms, might be best for powering nuclear plants, shielding soldiers from harm’s way and busting enemy bunkers.
But in the scientific community, uranium is recognized as a noteworthy element, not only for its real world applications, but also for its elemental properties – it is a weakly radioactive heavy metal.
Military use of depleted uranium, a byproduct of enriching natural uranium for munitions or nuclear power, has been a point of contention since its first widespread use in the first Gulf War, in which 320 tons were used.
The effect of radioactive material on living cells is well-documented but, until recently, the chemical properties of depleted uranium and how it affects living cells was not delineated.
A study put out by a woman originally from St. Paul proposes to change all that.
Diane Stearns, a professor at Northern Arizona University, published a study that suggests the mechanism by which depleted uranium affects mammalian cells.
Stearns said the study, which was put out by Northern Arizona University’s Native American Cancer Research Partnership, came out of interest expressed by American Indian tribes.
In the 1940s and 1950s, when uranium mining began in the Southwest, miners, many of whom were Navajo, were exposed to uranium and its carcinogenic daughter products such as radon.
Some of the exposed miners developed lung cancer. In 1990 the U.S. government issued the Radiation Exposure Compensation Act, which sought to compensate people who developed cancer and other illnesses from nuclear testing or uranium mining.
Stearns said her study focused on uranium as a heavy metal, rather than as a radioactive material.
“The big thing that we found is when you expose cells grown in the laboratory to uranium and isolate the DNA, it has uranium bound to it,” she said. “It could have effects as a radioactive metal because you have uranium right next to the DNA, but it also has effects as a heavy metal.”
Also, Stearns said, the mutations observed in the studies were different from what one would expect from mutations caused by radiation.
Stearns said conclusions from the study should not be directly applied to human health.
“We’re not trying to terrify everybody – this is what we found, so we reported it,” she said. “These are mammalian cells grown in the lab, not human.”
At this point, Stearns said, it only “raises the question.”
She said that hopefully the knowledge ultimately can be used to prevent harm.
“If we understand its chemistry, hopefully we can understand how to prevent the damage,” she said.
Bill Tolman, a McKnight and L.I. Smith professor in the department of chemistry and the Center for Metals in Biocatalysis, said the mechanism suggested by Stearn’s study is reminiscent of one of the most famous anti-cancer drugs, Cisplatin.
“That drug has been found to cure several different types of cancer,” he said. “It’s a really important and very simple platinum complex. It works by binding DNA and changing its structure, ultimately leading to cell death.”
Depleted uranium and the military
Because of depleted uranium’s density (about 1.7 times that of lead) and its self-sharpening properties, it is widely used in projectiles, especially in anti-tank munitions.
Some U.S. soldiers became extensively exposed to depleted uranium for the first time in the first Gulf War because of friendly fire and exposure to contaminated vehicles.
Critics of using depleted uranium sometimes name it as the main or a secondary cause to what commonly are called Gulf War illnesses.
However, there is substantial evidence to the contrary, said Melissa McDiarmid, medical director of the Veterans Affairs’ depleted uranium follow-up program.
A possible link between depleted uranium and Gulf War illnesses has been reviewed by “celebrated, blue-ribbon panels who know a lot about this,” McDiarmid said.
To date, she said, there is no evidence that depleted uranium could be responsible for Gulf War illnesses.
McDiarmid’s program has followed 74 veterans of the Gulf War who were exposed to depleted uranium by friendly fire.
The main finding of the program is that people who have been exposed to depleted uranium or have embedded depleted uranium fragments will have greater levels of uranium in their urine.
The veterans in the program are separated statistically into those with high urine-uranium levels and those with low levels.
To date, McDiarmid hasn’t seen adverse health effects in either category of veterans caused by depleted uranium.
She said researchers do not see statistical differences in organ systems, which she called “a good thing.”
“One of the reasons I think we haven’t seen any differences is because if you compared the urine-uranium burden of the soldiers I take care of to the burden that’s been measured and reported in workers (and miners) 40 or 50 years ago, the guys I take care of have much lower values,” she said.
That is good news, McDiarmid said.
“What that means is we haven’t passed a threshold that one might have to pass in order to start to see organ dysfunction,” she said.
McDiarmid said her program always has focused on depleted uranium as a heavy metal, because tests show an affected person’s total radiation level is low.
Another facet of McDiarmid’s program is the free test it offers to veterans who are concerned about possible exposure to depleted uranium.
“Any veteran in the whole country who has any concern about potential exposure can access our program through their local VA,” she said.
Not all people agree with the conclusions being drawn from McDiarmid’s study.
Tedd Weyman, deputy director of the Uranium Medical Research Centre, said his organization has found elevated levels in U.S. soldiers and citizens from Afghanistan, Iraq and the Balkans.
The Uranium Medical Research Centre is self-described as “an independent nonprofit organization founded in 1997 to provide objective and expert scientific and medical research into the effects of uranium, transuranium elements and radionuclides produced by the process of uranium decay and fission.”
Weyman said the number of people affected, about 50 percent to 65 percent of the total number tested, are exposed to the radioactive heavy metal.
He said these findings are “very troublesome for those that are dispersing it, like the army and the government and so on, because they don’t want people to know.”
He likened questioning uranium’s effects on the body to asking about the damage associated with smoking.
“The question represents the misinformation under which you have been propagandized,” he said. “In other words, uranium, as with all radionuclides, is an irradiating substance which releases particles into the environment.”
Weyman said that if radioactive material is inside the body, it immediately is doing damage at the cellular level.
“This is just fact,” he said.
There shouldn’t be differences drawn between uranium and depleted uranium, he said, because the effects are the same.
He said depleted uranium is 20 percent more radioactive than is generally accepted – about 80 percent the level of natural uranium.
“It’s like saying which is worse: getting shot with 10 bullets or with eight bullets – what difference does it make?” he said.
Weyman said uranium’s effect as a heavy metal and its radioactive nature both are important.
Michael Kilpatrick, deputy director for Deployment Health Support in the Office of the Deputy Assistant Secretary of Defense for Health Affairs, said there is no evidence to support depleted uranium affecting human health.
He said studies conducted on animals suggest uranium’s toxicity should not be tied directly to humans.
“The information is based on animal studies where, if you give an animal a very high blood level of uranium or depleted uranium in a very short period of time, it will cause kidney failure,” he said.
What’s interesting, he said, is that the level that causes kidney damage in animals is being exceeded in some of McDiarmid’s patients with fragments in their body, and their kidneys have adapted and are functioning normally.
Kilpatrick said the issue continues to be studied because people continue to be exposed.
“We are very concerned about the health of our men and women in uniform; we have a policy to do the testing should they be exposed,” he said. “We know that as long as it is outside of their body it doesn’t pose any health risk to them at all.”