...it has to be ingested to do its harm, a few atoms per person.
With that knowledge, there are things we can do to defend ourselves.
Technical Topic Papers
Rocky Flats Public Exposure Studies
Plutonium EXCERPT...
Why is plutonium a human concern?Plutonium emits alpha radiation and low-energy x-rays, which are easily absorbed by tissue. The alpha radiation travels only about a quarter of an inch in air and cannot penetrate the skin. Therefore, if plutonium remains outside the body, it is generally not harmful. Plutonium is very toxic if it enters into the body because the alpha radiation can damage living tissue. The larger the "dose" in the body, the greater the toxicity.
Human exposure occurs mainly by breathing contaminated air or ingesting contaminated food or drink. Breathing is generally the route of most concern. When plutonium particles are inhaled and lodge in lung tissue, they continue to give off radiation internally. They can remain in the lungs or enter the gastrointestinal tract and the bloodstream. About 80 percent of the plutonium that enters the bloodstream goes either to the liver, bone or bone marrow, where it is retained for years, damaging tissue nearby. That damage may later develop into cancer. Common forms of plutonium do not dissolve significantly in water or body fluids, so little ingested material is actually absorbed into the blood from the gastrointestinal tract.
How do scientists estimate human health risks from low-level exposure to plutonium?A great deal of research has been performed on the effects of radiation exposures at higher concentrations. However, little information is available for low doses of plutonium. Relatively few such exposures have been documented, with little solid evidence of effects. New information on exposures of Russian nuclear weapons plant workers has helped in developing better risk estimates for plutonium exposures. To estimate the risks of developing cancer from exposure to plutonium, the researchers conducting the Historical Public Exposures Studies on Rocky Flats used four independent sets of data:
1) Results of studies of Russian workers exposed to plutonium at the Mayak weapons plant, a production facility similar to Rocky Flats;
2) Data from populations exposed to other alpha-emitting radioactive materials such as radium, radon and thorium;
3) Data from Japanese World War II atomic bomb survivors exposed briefly to high levels of the gamma and neutron radiation from the atomic explosions; and
4) Results of controlled experiments on animals exposed to plutonium and other alpha-emitting materials.
Based on this information, the researchers developed revised estimates of the risks associated with plutonium exposure. (See the technical report Assessing Risks of Exposure to Plutonium prepared by Radiological Assessments Corporation for the Historical Public Exposures Studies on Rocky Flats in February 1999.) Because plutonium is retained in the lung, liver, bone and bone marrow, rather than in the reproductive organs, genetic risks are not the primary risks from plutonium.
CONTINUED...(with busted link I'm working on)
http://www.cdphe.state.co.us/rf/plutoniu.htm While we're currently not there, a freakish set of circumstances have brought about conditions for the worst case scenario. Let's keep learning and hoping and praying and DOING what we must.