For more than 100 years nuclear most experts believed that low levels of radiation have no negative effect on healthy people.
New research sheds great doubt on that previous assumption.
A new comprehensive study by scientists published in the peer-reviewed Cambridge Philosophical Society’s journal Biological Reviews reveals the worrisome discovery that even very tiny amounts of exposure to radiation in short bursts or over long periods can significantly harm life: "The effects of natural variation in background radioactivity on humans, animals and other organisms."
The study is comprised of an exhaustive review known scientifically as a "meta-analysis." The co-authors, biologist Timothy Mousseau of the College of Arts and Sciences at the University of South Carolina and Anders Møller of the University of Paris-Sud, meticulously analyzed more than 5,000 other studies that researched locations around the world with concentrated mineral deposits producing natural background radiation determined as being higher than average. The two scientists culled 46 representative peer-reviewed research papers from the universe collected to conduct an intensive quantitative comparison.
While many of the research papers they analyzed focused on the effects of localized background radiation plants and animals, a significant number of studies zeroed in on humans.
“When you’re looking at such small effect sizes, the size of the population you need to study is huge,” Timothy Mousseau explained to Steven Powell reporting for the University of South Carolina News. “Pooling across multiple studies, in multiple areas, and in a rigorous statistical manner provides a tool to really get at these questions about low-level radiation.”
The co-authors of the study drew primarily upon research of higher background radiation areas that included Ramsar, Iran, Mombasa, Kenya, Lodeve, France, and Yangjiang, China.
Although these areas have drawn scientific curiosity concerning the effects the higher radiation has on life, each study was limited in scope and tended to find very little evidence of any high impact the radiation had on plants, animals, or people. Although the background radiation was higher than normal, it is still considered to be very low levels of radiation.
The results of their study are disconcerting: even at very low levels, all lifeforms exposed to radiation exhibit significantly negative effects. The presence of the effects crosses a wide range, beyond that of random chance, and includes "immunology, physiology, mutation and disease occurrence."
Mousseau noted: “There’s been a sentiment in the community that because we don’t see obvious effects in some of these places, or that what we see tends to be small and localized, that maybe there aren’t any negative effects from low levels of radiation. But when you do the meta-analysis, you do see significant negative effects.”
The questions raised by the study will have an impact on the handling of nuclear materials, the nuclear power industry, response to nuclear accidents like the recent one in Japan, and the use of radiation in therapy, for diagnosis, and in security scanning devices.
“With the levels of contamination that we have seen as a result of nuclear power plants, especially in the past, and even as a result of Chernobyl and Fukushima and related accidents, there’s an attempt in the industry to downplay the doses that the populations are getting, because maybe it’s only one or two times beyond what is thought to be the natural background level," Mousseau explained. “But they’re assuming the natural background levels are fine.
“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.”