Some H-bomb test & reactor-borne isotopes, their radioactive half-lives & radioactive emissions
In the far-distant future, all the long-lived radioactive material,
even that now stored and trapped, will mix with the biosphere unless each
generation repackages it.
--Dr. Rosalie Bertell, No Immediate Danger.
Radiation is insidious, because it cannot be detected by the senses. We are not biologically equipped to feel its power, or see, hear, touch or smell it. Yet gamma radiation can penetrate our bodies if we are exposed to radioactive substances. Beta particles can pass through the skin to damage living cells, although, like alpha particles, which are unable to penetrate this barrier, their most serious and irreparable damage is done when we ingest food or water--or inhale air--contaminated with particles of radioactive matter.
|Uranium-238||alpha||4.5 billion years||used in new depleted uranium weapons and tank armor; contaminates 50 million tons of U.S. uranium mine wastes left in open piles|
|Uranium-235||alpha||700 million years||used in atomic weapons, poisoning fabrication factories|
|Uranium-234||alpha & gamma||245,000 years||left from uranium ore milling and enrichment|
|Plutonium-239||alpha||24,300 years||used in hydrogen bombs; seeks liver, lung, bone|
|Cesium-137||beta & gamma||30.2 years||left in large quantities from bomb production and in reactor wastes; contaminates whole body & muscle|
|Strontium-90||beta||28 years||spewed by accidents at Three Miles Island & Chernobyl--and vented in routine "allowable" releases by all operating nuclear power reactors; seeks bone|
|Cobalt-60||beta & gamma||5 years||left from H-bomb production & used in food irradiation; contaminates whole body|
|Iodine-125 & 131||beta & gamma||8.1 days||spewed in large quantities during reactor accidents and in fallout from above-ground bomb testing; contaminates the thyroid gland|
NUCLIDES OF RADIATION SIGNIFICANCE REGULARLY FOUND
IN "LOW LEVEL" NUCLEAR WASTE SHIPMENTS
Source: Radioactive Waste Management Associates, 526 W. 26th St., Room 517, New York, NY 10001
|Radionuclide||Half Life||Radiation||Critical Organs|
|Americium-241||430 years||alpha, gamma||bone & lung|
|Cerium-144||280 days||beta, gamma||GI tract, lung|
|Ruthenium-106||1 year||beta, gamma||GI tract, lung|
|Tritium||12 years||beta||whole body|
Alpha radiation, the nucleus of a helium atom, is a positively charged particle. It is larger in size than a beta particle, like a cannon-ball relative to a bullet, having correspondingly less penetrating power but more impact. Alpha radiation will travel about one millimeter in human tissue before stopping. It can be stopped by a single sheet of paper. Great damage can result from ingestion or inhalation where nearby cells are irradiated, because alpha and beta particles penetrate cell membranes. Plutonium is an alpha emitter and no quantity has been found to be too small to induce lung cancer in animals.
Beta radiation (almost 2,000 times smaller than an alpha particle) can penetrate several centimeters in human tissue. Stopped by metal or even thick cardboard. Beta passes through live tissue ripping electrons from atoms leaving positively charged ions that in turn ionize (irradiate) other atoms.
Gamma radiation are photons, i.e. high-energy light-waves and "pack a wallop" traveling in straight lines, knocking loose electrons, causing ionization, and leave a track of ionized particles in their wake. Gamma radiation is identical to X-rays of high energy. No radiation remains in the body after an X-ray picture is taken. It is like light passing through a window. The damage it may have caused on the way through, however remains. Gamma is the most penetrating form of radiation.
Background radiation is a vague term that includes emissions from radioactive chemicals which occur naturally and those which result from the nuclear fission process (nuclear reactor systems). Radioactive chemicals released from a nuclear power plant are called "background" after one year.
Rad and millirad: A radiation measure that refers to a unit of dose equal to the deposition of 100 ergs of energy per gram of material being irradiated; or the energy absorbed per gram of tissue which is equal to about 83% of the Roentgen value. A millirad is a thousandth of a rad.
Rem and millirem: A radiation measure that reflects the difference in biological damage of the radiation dose produced by different particles. The relation between rad and rem depends on the kind of particle emitting the radiation: for gamma rays, 1 rad = 1 rem; for beta, 1 rad = 1 rem; for alpha, 1 rad = 30 rem.
Roentgen: The original term used for measuring the amount of ionizing gamma radiation incident on the body. It is equal to .94 rads.