Answer to Question #611 Submitted to "Ask the Experts"

Q

I'm an environmental reporter in Portugal and I'm writing an article on the possible health effects both from radiation and chemical toxicity of depleted uranium. Which one is the most problematic danger? Why?

A

Recently, there has been much concern expressed in the media and among the general public with respect to the hazardous nature of depleted uranium, including allegations of leukemias, cancers, and other deaths caused by this material. While it is in fact true that depleted uranium is weakly radioactive, it is also a heavy metal and, except in certain very unusual situations, it is the chemical toxicity and not the radioactivity that is of concern. And, from a chemical toxicity standpoint, uranium is on the same order of toxicity as lead. Largely from work with animals, along with a few instances in which humans inhaled very large amounts of uranium, the chemical toxicity of uranium is known to produce minor effects on the kidney, which in humans who have suffered large acute exposures have been transitory and wholly reversible. Because depleted and natural uranium are only weakly radioactive, radiological effects from ingested or inhaled uranium have not been detected. Human experience with uranium has spanned more than 200 years. In the early part of the 20th century, uranium was used therapeutically as a treatment for diabetes, and persons so treated were administered relatively large amounts of uranium by mouth. Tens of thousands of persons have worked in the uranium industry over the past several decades and have been followed up and studied extensively, as have populations in Canada and elsewhere who have high levels of uranium in their drinking water. The types of illness apparently suffered by those exposed to depleted uranium from weapons have never been observed in these groups. This is not surprising as the radiation dose from uranium is far overshadowed by its potential chemical toxicity, and intakes of uranium of sufficient magnitude to produce chemotoxic effects are unlikely in and of themselves. That notwithstanding, any such effects from ingestion or inhalation of uranium would likely manifest themselves first in the form of minor effects associated with the kidneys. That military personnel and others who may have had contact with depleted uranium from munitions are suffering from various illnesses is not in dispute. That their illnesses are attributable to their exposure to uranium is very, very unlikely. A truly enormous body of scientific data shows that it is virtually impossible for uranium to be the cause of their illnesses. Health physicists are deeply concerned with the public health and welfare and, as experts in radiation and its effects on people and the environment, are quite aware that something other than exposure to uranium is the cause of the illnesses suffered by those who have had contact with depleted uranium from munitions. If we are to offer any measure of relief or solace to suffering people, and to gain some important additional knowledge in the process, we should not squander our valuable and limited energies, resources and time, traveling down a road that has already been well traveled and which has already shown us that uranium, either by itself or in combination with other materials, is almost certainly not the culprit. Rather we should put politics and political correctness, personal agendas, media coverage, and posturing aside and instead focus on scientifically determining what is in fact the cause of these illnesses. This would provide a true benefit to mankind; pointing accusing fingers at depleted uranium in the face of scientific evidence to the contrary is clearly wrong and counterproductive. Ronald L. Kathren Professor Emeritus Washington State University Past President, Health Physics Society Past President, American Academy of Health Physics