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?
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