Posted on 01/30/2005 3:33:09 PM PST by beavus
Low, chronic doses of gamma radiation had beneficial effects on meadow voles January 28, 2005 by Karen Kelly (about) (email)
A new study from the University of Toronto at Scarborough has found that low doses of radiation could have beneficial effects on health
The findings, published in the latest issue of Environmental Toxicology and Chemistry, found that low, chronic doses of gamma radiation at 50 to 200 times background levels had beneficial effects on the stress axis and the immune axis of natural populations of meadow voles. The paper provides evidence of hormesis from the only large-scale, long-term experimental field test ever conducted on the chronic effects of gamma radiation on mammals.
Hormesis is defined as a phenomenon in which low doses of an otherwise harmful agent can result in stimulatory or beneficial effects. This phenomenon has been observed in a broad range of chemicals including alcohol and its metabolites, antibiotics, hydrocarbons, herbicides, insecticides and fungicides, as well as physical processes such as radiation exposure. The effects of hormesis have been observed in a wide range of organisms, from microbes and fungi to plants and animals. Hormetic responses are varied in form and include increased longevity; growth, reproductive and physiological responses; and metabolic effects.
"Exactly how low-level radiation causes a hormetic response remains uncertain because few laboratories have studied the pathology or physiology of mammals exposed throughout life to dose rates below those causing detrimental effects," said Professor Rudy Boonstra of the Centre for the Neurobiology of Stress and Department of Zoology. “This study provides a potential mechanism to explain the benefical effects.”
In the study, Boonstra, along with researchers Richard Manzon, Steve Mihok and Julie Helson, studied the meadow vole populations at the Whiteshell Nuclear Research Establishment at Pinawa, Manitoba, Canada. The experiment, entitled ZEUS (Zoological Environment Under Stress), was set up by Atomic Energy of Canada to test the effects of chronic gamma radiation on natural populations. In isolated populations, voles received one of three radiation treatments over a four-year period.
"Our findings suggest that a moderate increase in glucocorticoid levels, associated with low-level radiation, could be an important factor underlying the increase in longevity that has been observed in other shorter studies on small mammals exposed to low-level radiation," said Boonstra.
The ZEUS experiment was funded by Atomic Energy of Canada and the hormonal analysis was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).
I'm sure not a scientist but since the study is focused on voles and voles typically aren't exposed to significant amounts of sunlight and its associated atmospheric radiations I think it possible the beneficial effects are illusory and simply compensate for a natural deficiency. I doubt the results could be extrapolated to demonstrate benefits to humans...unless of course they are trolls.
I worked for 4 years at a BWR, never had a cold or the flu in that entire time. My average exposure was 10 times what I got at a PWR, usually a mmrem or two a day, 5 days a week. A PhD working there told me about hormesis, but also told me it was a verboten subject to the NRC.
But if there truly is such a compensation, then doesn't that demonstrate that low levels of radiation are beneficial to at least one type of mammal? It is currently presumed that less radiation exposure is always better. This study seems to provide evidence to suggest that is not a universally valid claim.
What's the NRC's problem with hormesis?
Don't make me angry. You wouldn't like me when I'm angry.
NRC has enshrined the ALARA concept and doesn't want to upset the anti-nuke crowd.
Your point is well taken. However, my point is the perceived benefits are to a species that receives very little radiation to start with. Most mammals are daily exposed, and have adapted to, radiation from the sun. The voles spend most of their time in darkness. By the same token, I suppose blind creatures that live in caves, such as certain fish and insects, would benefit from exposure to radiation. They would either develop the ability to see or perish.
I can vouch for this. Radiation leaves me absolutely glowing.
Figures.
Well then, reading this study makes this old swabbie want
to grab his rag mop and head on up to Three Mile Island and
start cleaning up that mess.
You may be right, but the newsworthyness of the article is in the possible paradigm shift.
fascinating - thanks for the link.
DNA damage associated with UV light is qualitatively different than ionizing radiation damage, primarily thymine dimer formation. are you hypothesizing that this species has different responses to ionizing radiation as well?
I don't question the newsworthiness of the article. Thanks for posting it. I'm simply suggesting that there really may be no paradigm shift since the benefits appear to accrue only to small mammels and those that are deprived of natural sources of radiation to start with. Regards.
Because of the low radiation levels people are exposed to today, there really isn't substantial evidence to support the extrapolation the modern context. The best data are still dribbling in from Hiroshima.
But, in the absence of evidence, what should we presume? Primum non nocere.
The notion that low levels of radiation may be beneficial to ANY animals is a paradigm shift. Didn't your high school social studies teacher tell you? Radiation is EVIL.
"What's the NRC's problem with hormesis?"
It is not politically correct, to consider it in establishing public policy.
Fr some reason this makes me think of Randy Newman's song "Let's Drop the Big One Now".
I think a couple of survivors of the atomic bombings lived to 120.
Sorry, stepped away for dinner with my family. No. I'm hypothesizing that after offering my ill-informed, layman's view on the issue that I should drop out of this debate and leave it to those who really know what they're talking about. Just offered my little two cents worth. But you never know, sometimes out of the mouths of babes...as for what I was taught in high school beavis, they really didn't know that much back then. The Hiroshima results were still being analyzed. Freep on.
I'm definitely solar powered. Sunshine gets my heart started.
"Mortality and Longevity: Patterns of mortality apparently vary among meadow vole populations. According to Banfield [4] the average meadow vole lifespan is less than 1 month because of high nestling and juvenile mortality. The average time that adults are recapturable in a given habitat is about 2 months, suggesting that the average extended lifespan (i.e. how much time adult meadow voles have left) is about 2 months, not figuring in emigration [4]. Getz [23] reported mortality of 88 percent for the first 30 days after birth. Golley [25] reported that postnestling juveniles had the highest mortality rate (61%), followed by young adults (58%) and older age groups (53%). He estimated that nestlings had the lowest mortality rate (50%). Estimated mean longevity ranges from 2 to 3 months to 10 to 16 months [48]. Banfield [4] reported that the maximum lifespan in the wild is 16 months, and Johnson and Johnson [31] stated that few voles live more than 2 years."
What we need is a United Nations mandate to remove all radioactive potassium and carbon from the environment. No cost is too great for this pressing environmental emergency.
Good point.
bttt!
Accepted conventional wisdom states that ALL radiation exposure is bad. For the NRC to accept hormesis they would have to reject 60 years of preaching. They have even forbidden nuke plant training departments from formally mentioning the subject. Also, the entire anti-nuke crowd accepts current teaching on exposure as gospel and would go on a jihad against anyone who preaches this heresy.
Hormetic response ping!
The self repair capability in a biological system will simply be stimulated by low level inputs. As long as it isn't an overwhelming level of damage. The benefit of low level stimulation is analogous to keeping engine oil warm in an emergency generator. The mechanism is primed and ready to operate on short notice.
Nanotechnology in medicine...
"Hi Guys, I will add one more observation from an ill-formed layman. I did a little more research on voles. The average life span is only about a month or two at most. That means extended life is measured in days or maybe even hours. To me that would seem to indicate the benefits of radiation exposure can't really be measured against the long term effects of continuted exposure since they don't live long enough to realize significant long term effects. I suspect the results could represent something like the short term benefits of getting a sun tan."
That is a definite problem with making inferences from animal research. The much shorter life spans don't allow for really long term observation of effects.
Statistical studies show that residents of the Mississippi delta area get more cancers than people living at higher altitudes in Colorado. In the Mississippi delta, radiation levels - both naturally occurring and due to cosmic rays, are lower than areas such as Denver, where natural background radiation (Uranium, etc. in the granite) plus higher cosmic rays causes a higher level of radiation exposure.
Hormesis studies have been done ... and one accidental study was for a long-term low level exposure to lots of people. In Mexico City, a high rise apartment dwelling was built of steel that had a radioactive cobalt source that was melted/destroyed when the steel was mixed. The building was radioactive ... low level ... significantly above background, but not a high level (maybe 5 mRem/day ??).
Long term residents in the building ended up with significantly lower cancer rates after 5 years.
Hormesis is the concept used when someone with allergies gets allergy shots. Over time, the body's immune system learns how to better fight the problem. A body exposed to low level radiation may also learn how to better recognize and fight possible cancer cells.
Interesting concepts ... and probably worth more studies.
Mike
ping
Thanks for the ping!
National Commie-o-graphic had an article a while back about a spa somewhere in the Midwest (?) where there is a cave which produces natural radiation, and it has turned into a mecca for tourists to irradiate themselves (as well as the townspeople, who all have 7 arms and two... (never mind))
They're all convinced that it cures all their ills (hmmm.... I didn't note whether it cures Lie-beralism... should check into that)
Thank you for the post.
The linear accelerator techs could not enter the room for 10 minutes after zapping me because of the high levels of radiation in the air. The would fire 150 rads front to back, then rotate the aperture 180 degrees and fire back to front. The ionized air has a very acrid odor. As I became more conditioned, it was noticeable even in the waiting room.
Having had the experience, I'm not anxious to purposely experience radiation poisoning again. Even under controlled circumstances.
That is *A LOT* of radiation. (But you knew that...).
The doses referred to here (with however much credibility) are probably just a few multiples of background, not even diagnostic X-ray strength.
I'm not going for it either, though... (and I didn't even bring up the "radium water generators" they used to sell, but I'm sure a web search will turn them up)
If you can get past the anti-nuke crazies who fight this heresy tooth and nail. They scream about every attempt to fund hormesis studies and when they cannot stop them, their minions in the scientific community try to prevent publication and rational discussion.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.