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MIT Study: Prolonged Low-level Radiation Exposure Poses Little Risk
JSBiff sends this quote from MITnews:
"A new study from MIT scientists suggests that the guidelines governments use to determine when to evacuate people following a nuclear accident may be too conservative. The study (abstract), led by Bevin Engelward and Jacquelyn Yanch and published in the journal Environmental Health Perspectives, found that when mice were exposed to radiation doses about 400 times greater than background levels for five weeks, no DNA damage could be detected. Current U.S. regulations require that residents of any area that reaches radiation levels eight times higher than background should be evacuated. However, the financial and emotional cost of such relocation may not be worthwhile, the researchers say."
Because people with an 80 IQ or higher don't understand statistics, don't trust science, or what?
The article says low levels of exposure for five weeks resulted in no DNA damage. Five weeks is nothing, people living in contaminated areas will be there for years, and once radioactive material gets inside them it will be there for the rest of their lives. That is where the biggest danger is, long term internal exposure to material absorbed by the body into the organs.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Given the number of times one experts study is tossed out by another experts study why should I trust this 1 study, and what kind of assurances does anyone have that their isn't some kind of error and will be tossed out or ignored with the next study. How am I to know if this study wan't done to justify low level back scatter scanners at air port, and has fallen victim to confirmation bias of one form or anther?
My girlfriend loves my new found third leg. Thanks, radiation!
Funny, but "no detectable DNA damage" is not the same as "no DNA damage or other side effects". This study would need to be much longer term and need to look for more than obvious DNA damage for me to trust it, personally. It was only 5 weeks!
How can they really test every cell to determine if there has been damage? A longer term study monitoring cancer rates would be more useful. I'm not saying that we shouldn't question the current guidelines, but changing them because of a short study like this would be crazy.
This study would need to be much longer term and need to look for more than obvious DNA damage for me to trust it,
This study will never be trustworthy.
The danger to civilians from a nuclear accident is unlikely to come from background dose. That's more likely to be the exposure mode for workers and people very close to the incident.
found that when mice were exposed to radiation doses about 400 times greater than background levels for five weeks, no DNA damage could be detected.
No surprises there, but they didn't test what would happen when the mice ingested radioactive particulates, or when their entire food chain or water table was contaminated. Those are the real dangers from nuclear accidents.
"I've got more toys than Teruhisa Kitahara."
Btw, 100x background for 5 weeks is still less than the maximum year-long dose. Check the should-now-be-iconic xkcd radiation chart.
Those who fail to understand communication protocols, are doomed to repeat them over port 80.
it looks to me like the exposure was entirely external.
if you're breathing, eating, drinking and washing in the source then it's much more likely to be problematic.
Are you talking about chemical poisoning, or magical evil pixie dust. 125I decays emitting low-energy gamma radiation (the type that gets adsorbed adversely by living things). Eating this will have no different an affect than living right under it, as an object like a person, or mouse, is not a relevant shield for gamma radiation.
Now, if we were talking about inhaling dusted alpha emitters, then you'd have a point. However, those are either heavy metals, oxidize and drop out of the air, or decay rapidly to long-term emitters. The dust will be much more poisonous than dangerous as a radioisotope.
Damnit, I fed the troll.
There's nothing I detest more than some douche who has spent some time
at a university telling us all "we have nothing to fear".
Oddly, there's nothing I detest more than some idiot who is terribly afraid of something long after it's been proven to be safe.
I'd happily live in an area with 200x the level of background radiation (hey, my AT&T reception couldn't get any worse). The best benefit is that I can be sure compete morons like yourself will not be neighbors.
They said that about DDT.
Um, yeah...because DDT is safe. And millions have been killed from malaria that could have been saved without idiots like yourself "protecting" them.
Moron.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
How much energy do you think, a cell has to absorb for any of this "oxidative stress" crap to happen?
Contrary to the popular belief, there indeed is no God.
The amounts were tiny, but randomly sized/distributed particulates are notoriously hard to measure and map.
"I've got more toys than Teruhisa Kitahara."
Do you live near a freeway? That doubles the rate of atherosclerosis. Air pollution kills hundreds of thousands a year in the US, and also causes other significant morbidity like asthma in children. Way more dangerous that a measly radiation dose. Yet, I don't see people wanting to evacuate from around coal plants and freeways.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Funny, but "no detectable DNA damage" is not the same as "no DNA damage or other side effects". This study would need to be much longer term and need to look for more than obvious DNA damage for me to trust it, personally. It was only 5 weeks!
Not that much longer, a mouse goes from infancy to maturity in about 6 to 10 weeks, a year can get you a generation or two. A mouse can have 5 - 10 litters in a year and their lifespan is 9 to 12 months; 5 weeks for a mouse is like 20 years for a human.
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Are the mice a good model for human radiation risk?
Radiation induce cancer, but that does not mean cancer will thrive. It needs to be promoted. Diet and environment contain promoters. I suspect the mice in the experiment were not fed with growth hormone treated beef, for instance. First-world humans tend to have a diet that highly promotes cancer, therefore their risk may be higher than the mice in the study.
Sophisticated molecular and genetic analyses were not available in 1950s - 70s when many experiments investigating the effects of radiation on plants and animals took place; most were crude LD50 and cancer frequency tests conducted at moderate to very high doses, few were conducted at low doses (0.1 Gy) where cells could potentially repair the damage caused. This has all changed in the last ~20 years.
Sophisticated laboratory techniques now detect and observe the defence & repair mechanisms that operate in cells and whole organisms at low doses (100 mSv, ~0.8% increased risk of cancer in humans). For example, healthy people's cells repair all radiation induced DNA Double Strand Breaks (DSBs) within 24-hours after a CAT scan, indicating little or no additional risk of cancer. It is clear from resent experiments that living organisms are not passive accumulators of radiation damage but they actively combat and repair the damage done. After all, life involved with radiation and 3.5-3.8 billion years ago radiation levels were many times greater then now, it was necessary to evolve sophisticated error correction mechanisms. Indeed, it is likely that radiation is far less harmful or harmless below a certain threshold, possibly ~ 20 mSv year.
Crump, K. S. et al. 2012. A Meta-Analysis of Evidence for Hormesis in Animal Radiation Carcinogenesis, Including a Discussion of Potential Pitfalls in Statistical Analyses to Detect Hormesis. Journal of Toxicology and Environmental Health, Part B 15, 210–231.
Neumaier, T. et al. 2012. Evidence for Formation of DNA Repair Centers and Dose-Response Nonlinearity in Human Cells. PNAS 109, 443–448.
Löbrich, M. et al., 2005. In vivo formation and repair of DNA double-strand breaks after computed tomography examinations. Proceedings of the National Academy of Sciences of the United States of America 102, 8984 –8989
Tubiana, M., Feinendegen, L. E., Yang, C. & Kaminski, J. M., 2009. The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data. Radiology 251, 13–22. (Paper available without subscription).
you're an idiot. "background dose" is a unit, and refers to the average background radiation exposure of 360 mrem per year.
I keep forgetting that you have to explicitly explain everything on Slashdot or you'll be challenged on every minuscule aspect of your comment. Nevertheless, please read the Wikipedia article on background radiation, specifically the Human-caused background radiation section. http://en.wikipedia.org/wiki/Background_radiation.
But I'll repeat: Measuring the effect of steady-state external radiation, as this study has done, gives almost no insight at all on the effect of ingesting alpha-emitting particulates. It would be ridiculous to base public policy on it.
To trust the study from TFA would be about as sensible as measuring average wave heights off Honshu for 20 years, and concluding it would be a safe place to build a nuclear reactor.
"I've got more toys than Teruhisa Kitahara."
Right, what special magical property of the environment is this that relegates 'particles contributing to background radiation' external to humans? You do know that the primary culprit in 'background radiation' is radon GAS (e.g. an inhalant)...
And ultimately you are making an assumption not in evidence (e.g. that 'natural sources' of radiation are primarily absorbed externally while radiation doses from some 'accident' are primarily ingested or inhaled...not necessarily true in either case).
Really? Geez, let's be self evident...you never base 'public policy' off of 1 study.
From TFA "A new study from MIT scientists suggests that the guidelines governments use to determine when to evacuate people following a nuclear accident may be too conservative."
People are suggesting public policy should be influenced by it.
They are wrong.
"I've got more toys than Teruhisa Kitahara."
Maybe, but 5 weeks for mouse's DNA is like 5 weeks for human's DNA.
It's like the birds and rodents living happily in Chernobyl.
Who cares if you get a cancer after 15 years of radiation if your average life expectancy is 10 years?
If yes you might want to read this : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477708/
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Mice may not live long, but genetic damage will still take the as long to occur in mice as in humans. The fact that humans live longer means the damage has longer to accumulate.
So while 5 weeks may be "20 years" for a mouse's life span, it's still only a miniscule fraction of a human's lifetime in terms of how long damage has been accumulating.
The results of this study aren't merely questionable, they're completely useless.
I do not fail; I succeed at finding out what does not work.
So why does society decide that it makes sense to evacuate people from around Fukushima but not freeways if the risk is similar?
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Humans have *much* stronger anti-cancer mechanisms than mice. A mouse in its natural environment will take about three years to accumulate enough unrepaired DNA damage to get cancer; a human takes about 60 years. Five weeks of an elevated dose for a mouse is equivalent to about two years for a human, assuming the linear no-threshold model (the model that's the basis for public policy).
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.