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in reply to [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
in thread [OT] What is "the German Institute for Security in Information Technology"?
Thanks. (Though we're really getting off-topic now:)
The radiation in question was from Radon gas. We were looking at a property a few years ago and it was disclosed in the documentation that a survey has been done and over a 3 month period the level had never exceeded 114 Bq/M3. This being well below the UK government 'action limit' for households of 200 Bq/M3, it was, we were assured, "nothing to worry about".
A little research discovered that the 200 level was correct for households, and that for businesses it was 400. But looking around, the recommendations in different countries vary quite widely from as high as 1200, to as low as 150, and some research pointed to increased cancer risk at levels lower than 100 or even 80 of them Bq (whatever they are) /M3.
The variation, and the breadth of the variation got me to thinking about how the limits were determined, by whom, when, where and why. And without trying to retrace all the paths I took, I was left with the conclusion that they were quite literally "plucked from thin air". There seemed to be no one value, nor piece of definitive research, nor authoritative body that determined such values. That I could find anyway.
Since then I've read several articles and a seen a TV program about the aftermath of Chernobyl, and the most surprising and significant thing about them is that so far the affects of the radiation are not living up to their original cataclysmic predictions.
Of course there is some question as to whether there is full disclosure of the human costs by the local authorities. But other indicators, like birds nesting on the reactor building without any apparent harm coming to them, and the dramatic increases in wildlife, especially large mammalian wildlife in the exclusion zone. All these things make you wonder: a) how were those original cataclysmic predictions made; b) how do they decide upon the 'safe values' for short and long term exposure?
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
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Re^2: [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
by polettix (Vicar) on Aug 01, 2007 at 00:32 UTC
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I followed the issue quite closely here in Italy, and I can assure that most of the limits have been set for political reasons. The reasoning is more or less this: "ICNIRP identifies some thresholds, and sets limits that are 50 times below (for population)? Well, we can do better, we can drop it by other 3 dBs!". This at a national level. Then comes the local authority and says: "national limits? We can do better! Shove another 3 dBs!". There you go, without any real connection with the studies.
The rationale for this lowering is simple: "brief" studies can only apply to short-term effects (heating). But what if there are more subtle, long-term effects? Here come lower thresholds, but note that this issue can be addressed only with statistical studies over reasonable timespans. So the "I can do better" lowering race can be brought to whatever level you like: it's something that we don't know much about, so a lower level makes a better politician.
One interesting thing we had to reflect upon is that science will never, ever be able to say that radiations, at any level, aren't harmful. As a matter of fact, it cannot say this for anything we are aware of: we're only allowed to demonstrate that something can be harmful, not that it cannot be. So, it makes me laugh when they ask me "do EM fields harm?" - the only truthful answer being "we can never be sure they don't harm, evidence so far shows this and that, but it could be discovered something different in the future". Which sounds much like "we don't have a clue, just avoid them". So you have massive campaigns against "antennas" on the buildings, where a big chunk of the very same people is willing to put an EM emitter 3cm from the brain. Go figure!
Last, but not least, there is the issue of the non-disclosure of results, for political or economical reasons. Many research centers are privately funded, and are less likely to spread results that could harm "the industry". This is really sad, and eventually backfires to "the industry" itself.
Flavio
perl -ple'$_=reverse' <<<ti.xittelop@oivalf
Don't fool yourself.
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... I can assure that most of the limits have been set for political reasons.
Thanks for your time and expertise. That just about sums up the (lay) conclusions I reached.
It never ceases to amaze me the levels and diversity of expertise of the people that frequent this place.
Interactions like this just make me wish all over again that this place had an "off-topic" section--despite that I know that it has been discussed and dismissed many times in the past. I can't think of anywhere else I could have gone and got such a quick answer on this subject. The CB just isn't a substitute because its short lifespan means that only a few ever see a question and that excludes most of the monks, most of the time.
Maybe if posts to the section were discarded after some short period of time--say 1 month?
And maybe instead of the posts acquiring XP in the usual sense, voting could be translated into 'keep' votes that after some preset level deemed the post/thread worthy of retaining its disk space.
Ah well. Just another random thought for the bit-bucket.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
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Re^2: [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
by Zaxo (Archbishop) on Aug 01, 2007 at 03:47 UTC
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Bq is Bequerel, but I can't exactly recall its definition. I think it's either the number or energy of emissions per unit of time. My nuke books are all buried at the moment and CRC is unhelpful on the subject.
The data for massive radiation exposure came from Hiroshima and Nagasaki. It was not really possible to seperate radiation injury from blast and heat with any exactness. Lower level exposure data mostly comes from medical radiation treatment records. Those are generally distorted by the presence of cancer.
There is a big difference between external radiation exposure and the more dangerous incorporation of emitters in tissue. The latter is the case with Radon gas. Its alpha emission is stopped and absorbed by any amount of clothing or moisture or outer skin, but any that decays in the lungs injures the live cells and deposits radioactive heavy metals (Polonium isotopes) which do further damage while decaying to lead. Chemically toxic, too. Nasty stuff.
Obviously, controlled experiments can't be conducted in this realm.
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Obviously, controlled experiments can't be conducted in this realm.
Well no, not on humans at least. But the medical profession seem to be pretty good at extrapolating data derive from animal experiments. Whilst these may be controversial now, back in the 40s, 50s and 60s when most of the information relating to radiation effects was first being discovered and catalogued, there were fewer concerned about such things, but in the limited reading I did, I found very little reference to long term studies of that type.
Maybe they were done before electronic media was commonplace and so have never made the transition. Even so, you might expect to find some references. Or maybe they were all classified and haven't reached their declassification dates yet. Or maybe I just didn't look hard enough, or in the right places.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
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Re^2: [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
by CountZero (Bishop) on Aug 01, 2007 at 06:41 UTC
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The definition of becquerel is very easy: it is 1 / s (one per second), meaning one nucleus decays per second. So 150 Bq/m3 means that per cubic metre 150 nuclei will decay per second. It is thus just a measure of activity. It says nothing whether these decays make for harmful radiation. For all it means, these decays could produce quite harmless alpha radiation or hard x-rays.
CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James
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Re^2: [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
by moritz (Cardinal) on Aug 01, 2007 at 07:05 UTC
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As was pointed out earlier, Bq is just a number of decay events per time unit (1 second, I think) and says nothing about the possible harm on living organisms.
To measure that you have to know the dose equivalent in sievert. That's harder to measure, but only that value lets you asses the dangers of radioactive source reliably.
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Re^2: [OT over OT] Re: [OT] What is "the German Institute for Security in Information Technology"?
by BrowserUk (Patriarch) on Aug 15, 2007 at 00:04 UTC
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It just goes to show that there is always another study with different findings.
I just read this at the Beeb
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
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