Depleted Uranium101
by Glen Lawrence
Uranium is the heaviest element found in the earth in sufficient quantities to be extracted. Like most elements in the earth's crust, it's combined with other elements to form an ore. The ores are mined in places where there are rich deposits. In fact uranium is far more abundant in the earth's crust than gold or silver. The element uranium was discovered in 1789 by Klaproth, but it found little commercial value throughout the 19th and early 20th centuries. It was added to pottery glazes and glass for coloring. In 1896, the French scientist, Becquerel discovered x-ray like radiation emanating from uranium materials. This was shortly after Roentgen had discovered x-rays, so the phenomenon of high energy radiation was a new and fascinating topic at that time.
In 1938 the German scientists, Hahn and Strassman, discovered that lighter elements were formed when uranium was bombarded with neutrons. The alchemists' philosophers' stone had been realized, albeit not to produce the precious metal gold, but more of a Pandora's box of radioactive toxins. Within a few years scientists managed to transform this unusual property of matter into a weapon of war that forever has changed the concept of a weapon. The atomic bomb detonated over Hiroshima contained a relatively small amount of uranium (that would easily fit in a 1 quart milk carton), yet destroyed more than 5 square miles of that city.
Natural uranium found in the earth's crust is composed of 3 isotopes, U-238 (99.3%), U-235 (0.71%) and U-234 (0.054%). U-235 undergoes fission, meaning it can be bombarded with neutrons and will break apart into lighter elements, releasing tremendous amounts of energy in the process. U-238 absorbs neutrons, and rather than breaking apart, is transformed into plutonium. In 1938 there was virtually no plutonium on the face of the earth. Today there are thousands of tons of this highly radioactive and toxic material, formed for the purpose of building bombs, but also formed as a byproduct in nuclear reactors.
In order to get suitable material for bombs and nuclear reactors for electricity generation, it is necessary to enrich uranium in U-235. Each ton of nuclear fuel obtained in the enrichment process generates at least 7 tons of uranium that is depleted in U-235. This is known as depleted uranium or DU. The depleted uranium is a waste product because uranium metal doesn't have desirable properties for commercial use, although many have tried to find some. Depleted uranium is useful for radiation shielding in medical devices because the U-238 is good at absorbing radiation. The nuclear industry found that adding uranium to concrete made a very effective barrier for isolating highly radioactive waste at nuclear power plants. However, these commercial uses for DU haven't begun to put a dent in the greater than 500,000 tons of DU stockpiled at the uranium enrichment sites.
The military developed DU as a high density projectile in munitions; uranium is 1.7 times denser than lead and 19 times denser than water. Once this high density projectile is fired at high velocity, it isn't easily stopped. Think about throwing a sponge ball at a glass window, compared to a baseball. Not only is uranium a dense metal, it is also much harder than lead, piercing armor that would splatter lead. Furthermore, as it pierces through armor, it heats up to the point of igniting. When DU projectiles hit their target, not only do they go right through it, they catch fire as they do and completely destroy the target. DU became a highly desirable material for military munitions and quickly became the projectiles of choice for munitions ranging from 50 caliber sniper bullets and 30 mm ammunition on aircraft to 105 mm and 120 mm cannons on tanks. The 1991 Persian Gulf War was the first (confirmed) time the U.S. military got to use these munitions in combat. It is estimated that 320 to 350 tons of DU were used in the 1991 conflict. It was later acknowledged that DU munitions were also used in Kosovo and Bosnia.
Many scientists feel that the low level of radioactivity associated with depleted uranium is not sufficient to warrant concern about it being a health risk. This is based on the fact that we have trace amounts of radiation around us all the time; it's in our food and in our water. Our bodies have mechanisms for repairing damage done by radiation, provided we don't overwhelm these systems by bombarding them with large doses all at once. However, what most people neglect about uranium is that it's a toxic chemical element, just like lead, mercury, cadmium and chromium, to name a few. The toxicity of lead and mercury have been recognized for centuries because of their common and widespread uses since ancient times.
The public is well aware of the toxicity of lead and mercury. We know that we don't want people spraying these toxic metals around our homes for us to breath the dust or to have it leaching into our water supply. Congress enacted legislation over the years to protect the public as well as workers in industry from materials that are known to be toxic. Many of these substances are carcinogenic, but it may take many years after one is exposed to high levels of them before cancer develops, in some cases 10 to 20 years. The point is, these metals are known to be toxic chemically (they aren't radioactive), and the government has taken the initiative (albeit by public demand) to protect people from these toxins.
The nuclear industry is relatively young, and it was recognized from the very beginning that uranium could be a toxic material, although fear from its radioactivity has overshadowed concern about its chemical toxicity. Consequently, the nuclear industry built in safeguards from the very beginning to protect workers. This has led to a misperception among knowledgeable people in the industry that uranium is relatively benign. It was recognized that ingestion of uranium could cause kidney damage, but workers in the industry were not ingesting or breathing in sufficient amounts to cause noticeable kidney problems. The protective measures taken by that industry worked well to prevent widespread health problems.
The battlefield is a different story. As mentioned above, when DU penetrators pierce through metal or other hard objects, they burn. A typical 30 mm round fired by aircraft contains more than a half pound of uranium, which goes up in smoke when it burns. The smoke is a very fine aerosol of uranium oxides that are easily inhaled. If an aircraft strafes a target with hundreds of rounds (which only takes a few seconds of holding the trigger), there could be hundreds of pounds of DU going up in smoke, The particles are so small that they would not be noticed. They may remain suspended in the air for a long time and may travel on the wind for many miles. The levels of DU dust in destroyed vehicles could be quite high and easily resuspended in the air by unknowing individuals looking for souvenirs. Vehicles passing DU destroyed targets would also kick up the dust as they pass. This seems to be the scenario that prevailed in southern Iraq in 1991. There is no way of knowing just how much DU aerosol our soldiers were exposed to in that conflict.
Biochemists have known since the early 1960s that uranium binds very well to DNA. They used it often to prepare DNA for viewing in an electron microscope, because DNA by itself doesn't show up well. Only recently have scientists discovered that uranium will cause mutations and breakage in the DNA. Mutations and breakage of DNA can lead to cancer. Mutations and breakage of DNA in a developing fetus can lead to birth defects. Mutations and breakage of DNA in sperm and egg cells can lead to an unviable fetus that will spontaneously abort, or may survive to be born with severe deformities. Studies with lab animals have shown that this will happen to animals. Scientists study such toxicity effects in animals to better understand what might happen in humans.
Ethical issues for such experimentation on humans was dealt with in the mid-twentieth century by most societies, although there were many cases of such practices continuing well into the latter half of the century. How many animals do we need to sacrifice to convince people that uranium is genotoxic - that it can alter the genetic makeup of all generations to follow? Many doctors and scientists feel that the high incidence of cancers and birth defects in southern Iraq in the past decade is due to the DU dust remaining after the 1991 Gulf War conflict. There is clearly enough scientific evidence to implicate uranium as genotoxic. This means there is good evidence to implicate uranium as a carcinogen and teratogen (agent that causes birth defects).
Like lead and mercury, uranium is of the earth, but that doesn't mean we should be extracting it and then distributing it in highly concentrated form to specific locations where it will cause death and illness for generations. The battlefield has always been a dangerous place and many combatants have perished there in times of battle. DU munitions have added new dimensions to armaments. They not only destroy the enemy, but can blow back in the face of the conquerors. They don't stop killing when the battle is over, they can continue killing and maiming long after the fighting has stopped. DU munitions should be classified as chemical weapons of mass destruction. Their sinister action is different from nerve gas, but the toxic properties will linger a much longer time and will be passed on to subsequent generations - if they survive.
The military-industrial complex doesn't want to give up this effective and highly desirable weapon. DU ammunition is now available on the public market for anyone who wants it. How far does this have to go before the public takes notice? It is time to let representatives in the legislatures at all levels know that we understand that depleted uranium is toxic to humans and its use must be banned, especially for applications where it will remain in the environment for years to come.