Thank-you, Due - the article on the Mt. St. Helens Eruption is pretty decent.
Radioactivity in the Ash
There is radioactivity associated with all terrestrial
matter. Four of the most common radioactive isotopes
present in geologic material are 40K, 238U, 226Ra, and 232Th (primordialradionucides). Concentrations of4K, 226Ra, and 22Th in the bulk ash from the May 18 eruption ranged from 6.06 to 10.3 pCi/g,. 0.314 to 0.552 pCi/g, and 0.067 to 0.116 Ci/g, respectively.6'26 When 226Ra decays, a transition occurs from a solid to a noble gas, 222Rn(radon). Aver
Ce and one other item are the only 'commonly' measured radioactive contaminants (besides Radon - which is more a 'buzz-scare' than anything else) - the other common radioactive elements are not talked about a whole lot. There is no estimate of 'total radiation' from the four common ones (ie. concentration times total volume estimates) readily accessible for Mt. St. Helens. Please note, the amount of volcanic material released at the 'spreading plates' does dwarf single events such as St. Helens.
Good start - but not definitive.
The Radon levels of St. Helens were not a concern - because with such a short half-life, the concentrations have to be very high to cause concern. THis is NOT the case with very long half-life isotopes such as the common K,U,Ra, and Th isotopes released - ie. one can not compare the 'concentrations' and say that because the Radon was not a concern, that the others are not a concern.
And this begs the issue of comparison to total volume, total radiation release from Fukushima and vulcanics.
The articles you posted DID compare to 3MI - and said the vulcanics releases were 'several times higher' ...exact term 'many times more significant' than total radiation releases from 3MI.
Greatly appreciate the investigative work, Due - I was getting very little in a big hurry ... either you're better at searching, skimming, and more patient than I ... or .... all three. lol
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