Tuesday, June 19, 2012

"Run When You Hear 'No Immediate Danger' "


Speaking at press conference on March 25, 2011, Dr. Yablokov, author of Chernobyl: Consequences of the Catastrophe for People and the Environment, warned of the potential scale of the Fukushima disaster given plutonium fuel was involved :

We are seeing something that has never happened – a multiple reactor catastrophe including one using plutonium fuel as well as spent fuel pool accidents, all happening within 200 kilometers of a metropolis of 30 million people. Because the area is far more densely populated than around Chernobyl, the human toll could eventually be far worse in Japan… I am not optimistic about the situation at Fukushima. . .It’s especially dangerous if plutonium is released as inhalation of plutonium results in a high probability of cancer. A release of plutonium will contaminate that area forever and it is impossible to clean up.

Also speaking at the press conference was Cindy Folkers, radiation and health specialist at Beyond Nuclear :

At Fukushima, our concern is not just the immediate exposures, but exposures that occur over the long term, from radioactive particles that are inhaled or ingested. . . These particles can fall on soil and in water and end up in the food supply for many years. We are worried that officials are measuring only the radiation that is the easiest to detect – gamma rays. Testing people for radiation on their skin or clothing is necessary, but it tells us little or nothing about what they could have breathed in or eaten—which results in internal exposure and long-term risk.

Dr. Yablokov concluded  “When you hear ‘no immediate danger’ then you should run away as far and as fast as you can.

Majia Here: Dr. Yablokov's greatest concern was for plutonium. All alpha emitters are very bad for our health when ingested/inhaled, including Uranium, Polonium, Astatine, etc.

Yesterday I wrote about the volume of plutonium that may have vaporized. So, here is a bit of information about alpha particles. (Plutonium also emits gamma and beta but I'm going to discuss alpha only today).

Alpha particles are comprised of two protons and two neutrons. They are emitted from unstable elements such as polonium, uranium, and plutonium, among others. You can read about their properties at Wikipedia http://en.wikipedia.org/wiki/Alpha_particles

Alpha particles can be blocked by paper and are not thought capable of penetrating skin (although who knows given the surprises of biology).

Ingestion or inhalation of alpha emitters can be very destructive of health.  

William F. Morgan. Non-targeted and Delayed Effects of Exposure to  Ionizing Radiation: I. Radiation Induced Genomic Instability and Bystander Effects In Vitro writes.

a single α [alpha] particle can induce genomic damage in cells that were not Irradiated. Since a cell cannot receive a lower dose of radiation during exposure to α particles than a single traversal, these data suggest that at very low radiation doses the genotoxic risk  may be significantly underestimated” (Morgan, 573).

Majia here: Alpha particles can break your DNA and kill cells. They can also impact cells that were not even directly hit by the particle.

Two of the most important exposure effects recently explicated are “bystander effects” and “delayed effects.”  

Both of these effects can produce genomic instability. These effects were discovered as laboratory analysis examined the effects of ionizing radiation on both DNA repair and cell death.

 It was discovered that “bystander” cells not directly irradiated by radiation were often impacted nonetheless.  The effects on bystander cells also could take time to develop and were therefore “delayed effects.”

Genomic instability results from these bystander and delayed effects:

Genomic instability is an all-embracing term to describe the increased rate of acquisition of alternations in the genome. Radiation-induced instability is observed in cells at delayed times after irradiation and manifests in the progeny of exposed cells multiple generations after the initial insult. Instability is measured as chromosomal alterations, changes in ploidy, micronucleus formations, gene mutations and amplifications, microsatellite instabilities, and or decreased plating efficiency. . . . there are multiple pathways for initiating and perpetuating induced instability."  (Morgan, Non-Targeted and Delayed Effects, p. 567).

In effect, the researchers discovered that cells that initially survive irradiation are often unstable. New cells produced by the unstable cells can also be affected. 

Thus, radiation-induced genomic instability can result in a “cascade of genomic events that increase the rate of mutation and chromosomal change in the progeny of that irradiated cell”; however, the precise signaling events between cells that initiate and perpetuate the instability remain undisclosed.

Research on the bystander effect has also revealed that the signaling system between cells can also stimulate DNA repair mechanisms.  Corrective action stimulated by ionizing radiation is called “hormesis.” Unfortunately, no hormesis effects were found in the research on the effects of alpha particles I examined (and I examined quite a bit)

What relevance do the bystander and delayed effects have on current dose estimates given a single alpha particle can produce genomic instability? This question is relatively taboo in the scientific literature on the biological effects of radiation and it is noteworthy that it was taken up by Morgan in his review of non-targeted effects.



SOURCES

William F. Morgan. Non-targeted and Delayed Effects of Exposure to  Ionizing Radiation: I. Radiation Induced Genomic Instability and Bystander Effects In Vitro. Radiation Research, 159, 567-580.

Russian Chernobyl Expert Warns of Dire Consequences for Health Around Fukushima:Dense populations and risk of plutonium releases could mean Fukushima accident worse than Chernobyl, prominent Russian scientists says http://www.commondreams.org/newswire/2011/03/25-4.

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