[Peace-discuss] BBC nuclear gibberish - not 8 days, more like 3 months

[Morton K. Brussel]

From your reference:

But he also stressed there is "no immediate risk to public health," as the changing tides will dilute the iodine-131, and its half-life, or the amount of time it takes for it to lose half its radioactivity, is only eight days.

Another note:  No one knows exactly what "acceptable" is: It could be multiples of what has been currently set. 
[From Wikipedia:  http://en.wikipedia.org/wiki/Iodine-131.  
The risk of thyroid cancer in later life appears to diminish with increasing age at time of exposure. Most risk estimates are based on studies in which radiation exposures occurred in children or teenagers. When adults are exposed, it has been difficult for epidemiologists to detect a statistically significant difference in the rates of thyroid disease above that of a similar but otherwise unexposed group. ]

Your last two paragraphs are most pertinent. The concentration was evidently quite localized, and the sea is large. An instance of homeopathy |:=), based on the concept of hormesis [http://en.wikipedia.org/wiki/Hormesis] ? 

There's nothing very alarming here except that it indicates continued, not understood, leakage from the reactor complex. It might have come from the wash spilled over the reactors to cool them.

--mkb

On Mar 26, 2011, at 10:09 AM, Stuart Levy wrote:

> Heard last night a BBC report of very high (> 1000 times acceptable)
> levels of radioactive iodine in the ocean, a few hundred meters
> from the Fukushima plants.
> 
> This is alarming.  But more alarming is the completely *false* comment
> made twice during the report, once by the commentator introducing
> the story and again by correspondent Chris Hogg, that
> "after 8 days the levels of iodine will no longer be of human concern".
> 
> That sounds comforting.  Stay clear of the water for a week or two
> and everything will be fine, right?
> 
> That figure seems to be taken from the half-life of the longest-lived
> radioactive isotope of iodine, which is indeed 8 days.  But that is
> *not* the time at which it will cease to be of concern.
> 
> Given that the sampled water's iodine level was over 1000 (actually 1250)
> times higher than the amount considered acceptable, it would take over
> ten times iodine's half-life -- around *three months* --
> before radioactive decay would reduce it to 'acceptable' levels.
> 
> Of course other things would happen to the water in that time too --
> mixing with more ocean water, perhaps takeup by marine organisms.
> Decay isn't the only factor affecting environmental exposure.
> But this kind of misstatement is unconscionable.  And it's not hard
> to get it right, as in this Japan Times story:
> 
>    http://search.japantimes.co.jp/cgi-bin/nn20110326x1.html
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