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Wed Nov 14, 2012, 08:02 AM

Even Low-Level Radioactivity Is Damaging, Scientists Conclude (cross-post from LBN)

More support for the linear no-threshold (LNT) model:

Even the very lowest levels of radiation are harmful to life, scientists have concluded in the Cambridge Philosophical Society's journal Biological Reviews. Reporting the results of a wide-ranging analysis of 46 peer-reviewed studies published over the past 40 years, researchers from the University of South Carolina and the University of Paris-Sud found that variation in low-level, natural background radiation was found to have small, but highly statistically significant, negative effects on DNA as well as several measures of health.


I do question some of the researchers' commentary, particularly this:

"And the truth is, if we see effects at these low levels, then we have to be thinking differently about how we develop regulations for exposures, and especially intentional exposures to populations, like the emissions from nuclear power plants, medical procedures, and even some x-ray machines at airports."


From everything I know about how health physicists work, the LNT model is exactly what they do use in developing regulations. So what the study mainly does is validate the methods used all along. There's lots of room to debate things like what risks should be deemed acceptable and unacceptable, but professionals already use the model the study supports.

Of course, things are very different in public debates, where small risks either get turned into zero or negative risks by whoever supports a particular activity that results in radiation exposure, or amplified into visions of certain death by opponents of the same activity.

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Arrow 23 replies Author Time Post
Reply Even Low-Level Radioactivity Is Damaging, Scientists Conclude (cross-post from LBN) (Original post)
caraher Nov 2012 OP
Anthony McCarthy Nov 2012 #1
davepc Nov 2012 #2
Anthony McCarthy Nov 2012 #3
caraher Nov 2012 #19
wtmusic Nov 2012 #4
PamW Nov 2012 #5
RobertEarl Nov 2012 #6
PamW Nov 2012 #7
RobertEarl Nov 2012 #10
FBaggins Nov 2012 #13
PamW Nov 2012 #14
caraher Nov 2012 #18
PamW Nov 2012 #20
FogerRox Nov 2012 #8
PamW Nov 2012 #9
FogerRox Nov 2012 #11
Nihil Nov 2012 #12
PamW Nov 2012 #15
FBaggins Nov 2012 #16
caraher Nov 2012 #17
FBaggins Nov 2012 #21
dbackjon Nov 2012 #22
dbackjon Nov 2012 #23

Response to caraher (Original post)

Wed Nov 14, 2012, 08:17 AM

1. Three words, depleted uranium armaments

 

Will the scientists who said that those weren't a significant environmental danger on behalf of the producers and the military now lose their status as scientists? No, of course not. That would be unreasonable.

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Response to caraher (Original post)

Wed Nov 14, 2012, 08:43 AM

2. Welp, just turn off the Sun and we'll be all good then!

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Response to davepc (Reply #2)

Wed Nov 14, 2012, 08:49 AM

3. So drowning isn't a danger because we need water to live?

 

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Response to Anthony McCarthy (Reply #3)

Thu Nov 15, 2012, 01:35 PM

19. Actually, this reminds me of a different analogy

We all know fire is dangerous and excessive heat can kill you. But if I'm just warming myself by sitting in front of the fireplace am I harming my health?

There's really not enough information to know for sure - for instance, I might be an idiot and letting the fire burn with the damper shut, and soon I'll be overcome by smoke. But we also know that if the fireplace is properly ventilated and other simpler safety precautions are observed, there's no reason to be particularly fearful of sitting by the fireplace. And my resulting exposure to thermal radiation is not going to kill me (even though excessive heat exposure can and does kill people).

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Response to davepc (Reply #2)

Wed Nov 14, 2012, 10:15 AM

4. Ah ah ah...not so fast

A few more items:

Buy lead lined shoes and stop breathing
Live outdoors
Don't eat bananas
Don't fly

A lot to think about, but #1 pretty much takes care of the others.

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Response to caraher (Original post)

Wed Nov 14, 2012, 10:29 AM

5. Science says LNT is not correct

caraher writes
From everything I know about how health physicists work, the LNT model is exactly what they do use in developing regulations. So what the study mainly does is validate the methods used all along.


Caraher,

Actually the consensus among scientists is that LNT over-predicts the effects. The National Academy of Sciences in the BEIR ( Biological Effects of Ionizing Radiation ) Report states that we know that LNT is NOT correct and over-predicts the effects. However, they say that for the purpose of developing regulations, LNT can be used. That's because over-predicting is conservative; the regulations will be more stringent than necessary rather than too loose. Additionally, LNT has the simplicity that you don't have to know the detailed distribution of what you are regulating since the consequences are independent of how the dose is distributed. That is; if you have a fatal dose of "something", be it radiation or a toxin or whatever - it doesn't matter if you give it all to one person; or two persons,.... or thousands of people; you get the same one fatality, on average.

However, scientists know that LNT can't be correct since we know and have actually observed a DNA-damage repair capability. It's like an immune system for radiation. Scientists at Lawrence Berkeley National Laboratory recently published a study in the prestigious Proceedings of the National Academy of Sciences with evidence for the final nail in the coffin for LNT:

http://newscenter.lbl.gov/news-releases/2011/12/20/low-dose-radiation/

“Our data show that at lower doses of ionizing radiation, DNA repair mechanisms work much better than at higher doses,” says Mina Bissell, a world-renowned breast cancer researcher with Berkeley Lab’s Life Sciences Division. “This non-linear DNA damage response casts doubt on the general assumption that any amount of ionizing radiation is harmful and additive.”

PamW

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Response to PamW (Reply #5)

Wed Nov 14, 2012, 11:05 AM

6. Thanks, Pam

Yes, we all know that low doses of naturally occurring radiation are something life has adapted to. However, it is still damaging to life. Its just that life has adapted using DNA repair mechanisms.

Our problem is math.
First we have the low levels that life has adapted to using DNA repair mechanisms.

Now we are constantly adding more radiation leading to higher doses. And like you say, DNA repair mechanisms do NOT work much better at higher doses.

Call it natural if you like. I do not. Whatever. What we do have is higher background doses today than what we had 50 years ago. And we will continue to have higher and higher doses for the rest of our lives.

The question is: Can Life as we know it adapt?

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Response to RobertEarl (Reply #6)

Wed Nov 14, 2012, 04:47 PM

7. Radiation not much higher now.

RobertEarl,

Lets look at how much we have increased our doses over the last 50 years. Let's see what we have currently:

http://www.umich.edu/~radinfo/introduction/radrus.htm

Nuclear power and nuclear weapons fallout have each added <0.03% of our total.

So if we call the radiation levels today 100%; then the levels we had 50 years ago were 99.94%.

You make a bigger change than that if you don't live along the coasts, at sea level. If you live in the interior of the continent; where the ground elevation is somewhat higher; then you have a few hundred to a few thousand feet less air above you shielding you from cosmic rays; and that makes MORE difference than the radiation due to nuclear power and nuclear weapons fallout.

You are also in ERROR in saying that the rates are going up. They are pretty much constant.

Additionally, I didn't say that the DNA repair mechanism, "do NOT work much" at higher doses. I said they work better at lower doses as per the quote from the LBNL researcher. However, she didn't say that the DNA repair doesn't work at higher doses; it DOES WORK at high doses. However, it works better; and is virtually perfect at lower doses.

PamW

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Response to PamW (Reply #7)

Wed Nov 14, 2012, 11:54 PM

10. Heh, 2005 - 2012 .. 7 year old webpages

So I looked at your UMich link again. And here is what I found:

Page info: Modified Wednesday May 18 2005

Current Topics page
http://www.umich.edu/~radinfo/current/index.htm
Not even a listing for Fukushima

One of many dead, dead, dead links:
http://radefx.bcm.tmc.edu/ionizing/publications/nts.htm
Health Effects of Nuclear Weapons Testing by the United States of America

This being 2012 and 20 months after Fukushima, one would imagine that you, the scientist, would come up with a more updated and current website. But no.

No wonder you post such ill-informed opinions, you are working with and spreading links from 7 years ago. A lot has happened in 7 years, ya know?

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Response to RobertEarl (Reply #10)

Thu Nov 15, 2012, 10:15 AM

13. Why does it matter?

Do you really think that the last seven years have seen a notable increase in "manmade" radiation sources compared to hundreds of nuclear detonations in decades past?

Not even a listing for Fukushima

It would be pretty impressive for a 2005 website to contain a listing for Fukushima... don't you think?

Seriously... you've been corrected on this nonsense at least a dozen times. With the exception of the immediate site of a nuclear accident, natural sources of radiation exposure dwarf manmade sources. It isn't a close thing.

And it's well beyond contestation.

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Response to RobertEarl (Reply #10)

Thu Nov 15, 2012, 10:29 AM

14. WRONG!!!! WRONG!!! WRONG!!!

RobertEarl,

Once again you prove that the ill-informed, uneducated opinions on this site are YOURS.

One of the problems you have is that you "think" that Fukushima was some great calamity that eclipses all previous radiation releases, and that is just not true.

Chernobyl is still the worst radiation accident, and Fukushima is no Chernobyl. That was the conclusion of the President of the Health Physics Society, Dr. John Boice in his testimony to Congress in this current document:

http://www.hps.org/documents/John_Boice_Testimony_13_May_2011.pdf

On the top of page 2, Dr. Boice states:

Fukushima is not Chernobyl.

The health consequences for Japanese workers and public appear to be minor

The health consequence for United States citizens are negligible to nonexistent


RobertEarl is once again in ERROR. He has let his unfounded, and unsubstantiated assumptions
fool him into "thinking" that the data from the Health Physics Society is out of date. The head of this same
organization tells us that the effect in the USA due to Fukushima is "negligible to nonexistent". Therefore,
contrary to RobertEarl's ill-conceived claims above, the HPS data is not out of date.

NO, RobertEarl; when it comes to radiation exposure, a lot has NOT happened in the last 7 years.

If you want to comment / criticize a scientist; then go get some credentials; get yourself a PhD in the sciences.
Until then, you really have no credentials to criticize, and your time would be much better spent learning instead
of formulating ill-conceived conclusions absent the qualifications to do so.

PamW

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Response to PamW (Reply #5)

Thu Nov 15, 2012, 01:30 PM

18. My wording was perhaps a little too strong

But I think we're splitting hairs, unless you're trying to argue that there's something badly wrong with current health physics practice and we have some burning need to expose people to more radiation. FBaggins hits on the real importance below - we can use LNT as a useful upper-limit on the likely risk of low exposure with considerable confidence. That's essentially what I meant when I used the too-strong word "validates."

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Response to caraher (Reply #18)

Thu Nov 15, 2012, 04:04 PM

20. Definition of "validate"

caraher,

It all depends on what you mean by the word "validate".

When a scientist talks of having a model "validated"; it means that we've shown the model to be equivalent to what Mother Nature does.

We talk about "V&V" with our models - "Verification & Validation". "Verification means we are solving the equations properly.
"Validation" means we have the correct equations.

You are using "validation" in a different sense. You are saying that LNT has been demonstrated to be conservative, and an over-predictor.

Since LNT discounts any thresholds or any repair mechanisms; that is fairly readily apparent.

PamW

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Response to caraher (Original post)

Wed Nov 14, 2012, 05:01 PM

8. DO all humans respond in the same manner, as a monolithic block?

TO low doses?

I'm guessing no.

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Response to FogerRox (Reply #8)

Wed Nov 14, 2012, 07:19 PM

9. Think about Vaccines!!

FogerRox,

Think about vaccines. Do all humans respond 100% exactly the same to a vaccine as all others?

NO - in fact some people have allergic reactions to some vaccines.

Does that mean that vaccinations are useless, or should be discontinued?

NO! In a sense, since we all have the same basic DNA programming to a great degree, we all respond generally the same way to vaccines and vaccinations. That's what makes them useful. That's why the Centers for Disease Control can estimate which strains of flu will be prevalent in a given winter and we can get flu shots that decrease our chances of getting the flu.

Are flu shots 100% effective for 100% of the people? NO.

However, where did we get this requirement that everyone has to respond the same or something is no good?

We all respond basically the same to flu shots; but with occasional differences. We don't let those differences stand in the way of the utility of vaccinations and flu shots.

Basically, we all have the same DNA repair mechanism; but with some differences.

However, we shouldn't let those small differences dissuade us from accurate assessments of radiation risks.

When you examine the sources of radiation from the University of Michigan website; we see that the radiation that we get from nuclear power and nuclear weapons fallout are a very small fraction of our total exposure. The number one source of exposure to radiation for the average person is good old Mother Nature at 82% of our average exposure.

There's actually a rather large variation in that average depending on what altitude we live at, and what part of the country. The concentration of radioactive materials in your environment is dependent on what rock formations Mother Nature put down in the area in which you live.

Medical use account for another 15%; and those have been very beneficial. Medical doctors take into account the benefits vs. risks when ordering tests and treatments involving radiation. Only when the benefit exceeds the risk is the procedure ordered.

Another large variable is how much time you spend in airliners. Pilots and flight crews can increase their exposure by 50% or more due to their occupation.

In all this; the rather small contribution from nuclear power almost gets lost in the noise. There's no great increase in risk due to the use of nuclear power, and the elimination of said exposure would be a trivial reduction to our exposure.

PamW

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Response to PamW (Reply #9)

Wed Nov 14, 2012, 11:55 PM

11. Think about 2, 20 yr old brothers standing outside Hiroshima, watching the bomb drop

One gets cancer and dies in 1959, the other still lives at age 87.

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Response to FogerRox (Reply #11)

Thu Nov 15, 2012, 07:27 AM

12. Bet I can guess ...

... which one was hiding behind the other!




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Response to FogerRox (Reply #11)

Thu Nov 15, 2012, 10:31 AM

15. Did this happen?

Do you have some evidence that this has happened?

You can "suppose" all you want. Suppose I drop two identical billiard balls
at the exact same time and one of them hits the ground several seconds before the other....

Tell you what. Why don't you "if" in one hand and spit in the other. Then tell me which
one you have more of.

PamW

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Response to caraher (Original post)

Thu Nov 15, 2012, 10:39 AM

16. Something of a stretch to call them "scientists" at this point.

Last edited Thu Nov 15, 2012, 11:23 AM - Edit history (1)

These same two have been producing this nonsense for many years now. They didn't actually perform any science... or do anything beyond review others' research and apparently cherry-pick it at that - selection a tiny sub-sample of the data(less than 1% of the papers reviewed). There are far more than 46 studies out there that look at areas of the globe with high background levels yet lacking in any evidence that the higher background levels negatively impact health of the local population. Shall we cherry-pick those and claim exactly the opposite?

From everything I know about how health physicists work, the LNT model is exactly what they do use in developing regulations.

Yes... because it's the most conservative approach, not because the consensus is that it's correct. Health physicists largely agree that there isn't an identifiable impact to doses below about 100msv. Not that there isn't any impact, but that it's too small to identify within normal statistical variation within the population. IOW, if normal cancer rates imply that 10-15 people out of a population of 100,000 will acquire a particular type of cancer and a given rate added one person to that total, you wouldn't be able to demonstrate it, because the normal statistical range is so much larger than the presumed impact.

So to be on the safe side, they adopted LNT so that they would have something to work with. There is some data supporting LNT and some data that implies a lower risk than LNT indicates and that doses below some threshold have no negative impact. When faced with those possibilities and the fact that whatever the risk is can't be detected with current epidemiological methods... what's the safe play?

On edit - It's interesting to note what they don't support. And that's the whacky notions of Busby/Caldicott/etc who want to pretend that LNT dramatically under-estimates the risk from very low levels of radiation.

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Response to FBaggins (Reply #16)

Thu Nov 15, 2012, 01:24 PM

17. I have no prior familiarity with their work

I do understand that LNT is used as a conservative model, in order to have *something* to calculate. I also admit that I don't know enough of the details of the sort of meta-analysis this latest (and their work) paper represents to assess how thorough and bias-free it is.

But it is very pertinent to note, as you do, that they find no warrant for the idea that we're vastly understating the risks. I think it's of mainly academic interest whether the correct model is LNT, a threshold model or even one with a hormesis effect, in that none of those choices being ultimately correct would mean that current regulatory practices expose the public or workers to excessive risk through ignorance of the real dangers. But it is very significant in practical terms if even researchers considered to have a bias in favor of inflating radiation hazards find no evidence for risks beyond those calculated by widely-used LNT models.

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Response to caraher (Original post)

Fri Nov 16, 2012, 12:07 PM

21. Here's a much more significant study.

Just published a week or two ago.

http://www.democraticunderground.com/112728344

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Response to caraher (Original post)

Fri Nov 16, 2012, 12:58 PM

22. It is amazing life exists at all

Damn that radiation, making mutations, etc.

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Response to caraher (Original post)

Fri Nov 16, 2012, 12:59 PM

23. High Levels of Oxygen are fatal.

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