by Karl Johanson
At 8:30 AM on May 18, 1980, a major release of radioactive material took place in Washington State. The explosive event, which caused the release and killed 61 people, was covered quite extensively by the news media; however the release of radioactives wasn't mentioned. Wherein the accident at the Chernobyl power plant released an estimated 7,000 kg of radioactives (the vast majority of which were U 235 and U 238), estimates of the amounts of radioactives released in this event include the following:
Rubidium 87 337,000,000 kg
Potassium 40 300,000,000 kg
Thorium 232 170,000,000 kg
Uranium 238 59,580,000 kg
Uranium 235 420,000 kg
Uranium 234 32,000 kg
Thorium 230 1,050 kg
Radium 226 22 kg
Protactium 231 20 kg
Lead 210 .3 kg
Radium 228 .06 kg
Thorium 238 .018 kg
Actinium 227 .013 kg
As well as the above, the following radioactives were released in trace amounts:
Asatine, 215, 216, 218 & 219
Bismuth 210, 211, 212, 214 & 215
Lead 211, 212 & 214
Polonium 210, 211, 212, 214, 215, 216 & 218
Radium 223 & 224
Radon 219, 220 &222
Thallium 206, 207, 208 &210
The event which expelled the radioactive material involved a release if energy 500 times that of the bomb used on Hiroshima (500 hectares of land was devastated and shock waves shook houses over twenty miles away).
Twenty-five per cent of the material was emitted directly into the atmosphere, the remainder was spread over the nearby countryside. The material emitted into the atmosphere was deposited on areas of Washington, Idaho, and Montana. Most the remainder of the airborne material landed on a large part of the United States and Canada.
While many of the radioactive elements have short half-lives (and thus high specific levels of radiation), the amounts of these short-lived elements will remain at approximately their current levels for some time. The high-level radioactives will decay, but they are daughter elements and will be produced as the Th 232, U 235 and U 238 break down over their half lives (Th 232's half life is 14 billion years, U 235's is 704 million years, U 238's is 4.47 billion years).
One can expect to find roughly the above amount of radioactives in any 4 cubic kilometres of the earth's crust.
If anyone is curious, the event which caused all this havoc, was, of course, the eruption of Mount St. Helens.
Originally published in Under the Ozone Hole – Number One – August, 1992.