Hi 10k-jaro ,

   That was an informative reply on the ESA's Southwood's insistence on pu-238. Yes, it would be nice to explore beyond Saturn, and the definition of deep space will be ever changing.

   I have 2 objections, if you care to address them...

1) The Cassini is cited in these articles. As I have already stated, the Cassini, deep in their own documents, risked contaminating 2/3's of the world with a pu-238 burnup if they missed the sling shot acceleration manuever. How much pu-238 do doctors recommend for pregnant women? The answer is zero because of the radiosensitivity in the womb.

   So basically these rocket scientists are willing to risk most of the world's environment and developing children for their project. That is unacceptable to me and most of the people on earth, who's health you appear willing to gamble with. We have plenty of science we can do, and new energy breakthroughs can be achieved that do NOT risk this assinine gamble.

2) Why not do the science of HEPA filters, after 50 years of polluting the planet? Why allow the DOE to ignore the NAS advice for "emissions free treatments" for pu projects? And YES, there will be "spinoff technology" benefits for mankind by doing this science of pu containment, from vacumn cleaners to clean air.

    I do not oppose science and space exploration, but the DOE is presently lying about safety. pu-238 is SO radioactive that "any inhalation" for workers is assumed to exceed the workers 5,000 mrem annual dose limit. The recent pu-238 accidents at Los Alamos put the workers on immediate chelation therapy, to attempt to withdraw the pu-238 from their bodies, but they were over the 5,000 mrem dose regardless. Limit of exposure to the public is 10 mrem, or about one chest x-ray, which, ummm, you would not give to a pregnant women, unless her life depended on the x-ray. A space burn up will not have citizens undergoing chelation therapy, and it will be a disaster we do not need to gamble on.

   Please don't confuse inhalation of pu-239 for weapons with pu-238. The pu-238 is 275 times more radioactive, and that much more tissue and genetic destruction occurs with pu-238 exposure. Getting Bush's "man on Mars" may sound fun to unaware scientists who love science like I do, but when you are aware of the Big Picture, it is cruel and unusual punishment to the downwind citizens of the production facility, and the citizens of the world.
   

stungun wrote:

---

Please don't confuse inhalation of pu-239 for weapons with pu-238. The pu-238 is 275 times more radioactive, and that much more tissue and genetic destruction occurs with pu-238 exposure.

---

Thanks for reminding me that  Pu-238 is 275 times more radioactive than Pu-239 -- I didn't realise that I was confusing it with Pu-239.

It would have been nice if you had added why that is so :  because the radioactive half-life of Pu-238 is 275 times shorter than that of Pu-239 (24,400 years versus 86 years).

Well guess what -- the half-life of typical radiopharmaceuticals is about 36 million times shorter than Pu-239, making them that much more radioactive (there is a biological effectiveness factor that also enters into the calculation, due to the different kinds of radiation, but this is generally not more than a factor of ten).

Similarly for some of the naturally occurring radioactive materials (NORMs), like for example Polonium-210, which is 64,500 times more radioactive than Pu-239, and 227 times more radioactive than Pu-238 (and same kind of radiation too - alphas - in this case).

If you want to talk about the "Big Picture," consider the following.

Typically, the first top meter of a 15 by 25-metre house lot contains, on average, three kilograms of uranium and ten kilograms of thorium.  One of the elements borne from the decay of uranium is a gas called radon. Radon escapes continuously to the air from the surface of the earth. On average, every square meter of land releases about 10 thousand atoms of radon every second, that is, a source of 10,000 Becquerels. Radon, which is also radioactive, decays into a series of radioactive atoms, one of them being Polonium 210. Rain, fog, snow, and dust bring polonium 210 back to the ground, where it accumulates. Since the source of radon never stops, the quantity, and the activity (quantity) of polonium on the ground remains constant at about 10,000 Becquerels per square meter. The International Commission on Radiological Protection calculates that polonium-210 is five to ten times more harmful than plutonium 239, on a per-radioactive quantity basis (i.e. on top of the 64,500 factor for half-life applied on the per-unit-mass basis) . Therefore, in terms of theoretical risk of cancer due to radioactivity, 10,000 Becquerels of polonium 210 are equivalent 50,000 to 100,000 Becquerels of plutonium 239. If one converts the quantity of polonium 210 on the ground into a mass of plutonium that presents the same theoretical danger to health, there is the equivalent of 0.044 mg of plutonium per square meter of land. This does not look like much, but for the Province of Quebec alone – an area of 1.5 million square kilometers - this is equivalent to some 60 tons of plutonium 239 -- or 220 kg (480 pounds) of Pu-238. This is the normal natural radioactive "fallout" -- way more than a remote chance of a spacecraft like Cassini crashing its load of 70 pounds of Pu-239 somewhere into the deep ocean.

 
So puh-leeeze.... go hawk your scare stories on some other message board. You may have better luck finding sufficiently ignorant (read 'gullible') victims for your propaganda there.
 
Oh, and BTW, that's 10kBq - as in kilo Becquerels, the typical amount of natural radioactivity in a human body.
 

I am very glad 10kBq Jaro mentioned how naturally occurring radon decays into Polonium-210. I wonder if Stungun is perhaps a cigarette smoker. No matter. Cigarette smoke contains Polonium-214 and 210. Read web page:

http://www.prfamerica.org/RadioactivityInCigaretteSmoke.html

I'll wager cigarette smoke causes more harm (regardless of its radioactivity, but that certainly is a contributor) than any hypothetical break-up of an RTG-powered satellite or spacecraft from orbit.

Well, said, 10kBq Jaro: "...go hawk your scare stories on some other message board. You may have better luck finding sufficiently ignorant (read 'gullible') victims for your propaganda there." And Lord Flasheart, thanks for the link to the article on the Calculation of Radiation from Casini. I saved that in a special pro-nukes folder I maintain to combat the idiocies of enviro-wackism (where the "ISM" stands for "I, Self, and Me").

Regards,

Paul P.

Hi Lil' Lord,

   I read your reference, but my source is Dr Scott, who is also on a National Academy of Science panel. He is very pro-nuclear, even loves hormesis to pieces! But his paper on pu-238 inhalation states "any inhalation" of pu-238 should be assumed to exceed the 5000 mrem annual limit.

     Your source is cute, but not published.

 

"Thus, rather than addressing questions such as 'Did the calculated worker's intake of (PuO2)-Pu-238 exceed the ALI?', it is better to address questions such as 'What is the probability that (PuO2)-Pu-238 intake by a given worker occurred and exceeded the ALI?'"

---

Citing Articles--Full Record

Article 2 of 2

---

Variability in PuO2 intake by inhalation: Implications for worker protection at the US Department of Energy
Scott BR, Fencl AF
RADIATION PROTECTION DOSIMETRY
83 (3): 221-232 1999

Document type: Article   
Language: English   
   
       
Abstract:
This paper describes the stochastic exposure (SE) paradigm where, at most, small numbers of airborne toxic particles are presented for inhalation. The focus is on alpha-emitting plutonium dioxide (PuO2) particles that may be inhaled by Department of Energy (DOE) workers. Consideration of the SE paradigm is important because intake of only a few highly radioactive PuO2 particles, such as (PuO2)-Pu-238, could greatly exceed the annual limit on intake (ALT) used to control worker exposure. For the SE paradigm, credible intake distributions evaluated over the population at risk are needed, rather than unreliable point estimates of intake. Credible distributions of radiation doses and health risks are also needed. Because there are limited data on humans who inhaled PuO2, these distributions must be calculated. Calculated distributions are presented that relate to the intake of radioactivity via inhaling polydisperse PuO2 particles. The results indicate that a large variability in radioactivity intake is expected when relatively small numbers of PuO2 particles are inhaled, For the SE paradigm, one cannot know how many PuO2 particles were inhaled by an individual involved in a given inhalation exposure scenario.   Mathematical tools for addressing the latter question are presented, and examples of their applications are provided, with emphasis on possible DOE worker exposures at the Rocky Flats facility near Denver, Colorado. The alpha-emitting isotopes Pu-238, Pu-239, Pu-240, and Pu-242 are found at Rocky Flats. Although Pu-238 is thought to be present in relatively small amounts there, intake via inhalation of only a few (PuO2)-Pu-238 particles could greatly exceed the ALI.

Yes, my source was cute, wasn't it? Moreover, it was to the point. Facts are facts, even if they aren't published.

Published papers, properly peer-reviewed, are certainly a good resource.
One such paper is "Fifty Years of Plutonium Exposure to the Manhattan Project Plutonium Workers: an Update" by George L. Voelz, James N. P. Lawrence and Emily R. Johnson, in the October 1997 issue of Heath Physics :
 
<quote>
INTRODUCTION
Plutonium is arguably the most feared substance on earth. Some people are convinced that any uptake of plutonium, sometimes referred to as a "speck," by an individual guarantees the induction of cancer and subsequent death. The health experience of workers exposed to plutonium provides important data to study the validity of such fears. The 50-y anniversary of plutonium exposures to a group of plutonium workers is a worthy time to take note of their experience.
Significant internal plutonium depositions occurred in a group of 26 young males who worked on the Manhattan Engineer District's Project "Y" at Los Alamos in 1944 and 1945. [....]
Hempelman et al. (1973) described the working conditions for these young men as "extraordinarily crude." Some procedures, such as centrifuging and weighing of plutonium, were done in open rooms. Ordinary open-faced chemical hoods offered the principal protection during chemical and metallurgical procedures. Half-faced, filter paper respirators used during most of this period were what was available in the 1940's and were not up to today's respiratory protection equipment standards. The plutonium recovery was perhaps the most hazardous operation and resulted in exposures to 14 of these individuals. [....] Inhalation of plutonium particles was the main exposure pathway for all these workers.
[....] This group of exposed workers has been examined medically about every five years since 1952.
This report includes the results of the last medical examinations done in 1991 and 1992 at Los Alamos.
[...]
The data on these 26 plutonium exposed workers have consistently indicated over the 50-y follow-up period that the mortality rates for all causes of death and for all cancers are not elevated compared with that of U.S. white males and unexposed Los Alamos workers with comparable hire dates. This finding differs from some popular misconceptions that large health risks occur with any exposure to plutonium.[....] As of the end of 1994, 7 individuals have died compared to an expected 16 deaths based on mortality rates of U.S. white males in the general population. The standardized mortality ratio (SMR) is 0.43. When compared with 876 unexposed Los Alamos workers of the same period, the plutonium worker's mortality rate was also not elevated (SMR = 0.77). The 19 living persons have diseases and physical changes characteristic of a male population with a median age of 72 y (range = 69 to 86 y).
<end quote>
 

As regards Radon, a very good paper is "Test of the linear-no threshold theory" by Bernard L. Cohen, in the February 1995 issue of Heath Physics.posted at http://www.phyast.pitt.edu/~blc/LNT-1995.PDF (8.8 MB PDF)

<quote>
A compilation has recently been completed of average indoor levels in 1,729 U.S. counties, over half of all U.S. counties and representing nearly 90% of the total U.S. population. [....] there is a strong tendency for lung cancer rates to decrease with increasing radon exposure....
<end quote>
 
 
More interesting reading :

http://lifestyle.scotsman.com/families/columnist_specific.cfm?articleid=2823&columnist=FC1

Radio head

Kath Gourlay, The Scotsman Tuesday, 6th March 2001

Eric Voice shows not the slightest emotion as he describes himself as "the most radioactive man on the planet". He speaks as precisely as he dresses; the pronouncement is not meant to shock or scare. Said by someone else, it could perhaps be taken for some kind of joke.

But Voice is not the sort of man for lighthearted distractions. For over a decade the retired nuclear scientist has voluntarily taken part in human experiments on the effect of plutonium to prove his belief that it has no harmful effect whatsoever on his health.

He has willingly allowed his body to be filled with plutonium - often described as the most dangerous substance known to man - first by injection and then through direct inhalation. Going to such lengths publicly to re-affirm his faith in its safety may horrify some but Voice stands by his convictions, believing that what he does is for the good of mankind.

"This fuss about plutonium is largely media hype," he says. "The truth of the matter is that it’s a well-known chemical element and there is nothing sinister about it."

Voice, 75, is a wiry man with steely blue eyes. He looks years younger than his age. It is hard to believe that half a century ago, he was one of the founder members of the CND movement with Bertrand Russell . He says he realised from an early age that making protests from outside achieved very little and felt more influence could be brought to bear working from within the industry.

His convictions go back 56 years to when he heard the news that an atomic bomb had been dropped on Hiroshima. "I was so appalled. The most momentous discovery and what had man done? He’d used it for aggressive purposes and sealed its fate for generations. I swore that from then on I’d work towards utilising this wonderful source of energy for the benefit of mankind."

Voice spent 15 years in biochemical research and 28 years in the nuclear industry, many as a chemist at Dounreay. One of the first scientists on the Dounreay site, he worked out of a Nissen hut while the complex was constructed, and still lives in the coastal town of Thurso.

Two years ago, Voice caused a stir by stating: "People still do not understand plutonium and there is such a lot of nonsense talked about it.

"There is no evidence that any human on Earth has suffered in health from plutonium and I have no adverse effects."

He remains convinced that nuclear power is our only hope for the future in the fight against global warming. The lengths to which he has gone to justify these beliefs are extraordinary.

His neighbours are used to the regular visits of an armoured van to pick up his bodily waste, for example. "The practicalities can be a bit irksome but I’m used to it. When I arrive at people’s houses with a carrier bag of bottles, people assume I’ve brought them a gift," he smiles. "When I explain I can’t use their facilities their expressions are extremely comical." Quite. Which invites the next question. He’s not in his first flush of youth, so what will happen to his body when he dies? His reply - "It has all been responsibly taken care of" - politely prohibits further discussion.

So what does he hope to prove by doing the experiments? "It is the duty of those involved in the industry to ensure strict safety limits for workers worldwide," he says. "That was always one of my aims and I feel I’ve done something useful and practical towards that end."

Voice, who is married, is fiercely protective of his family and refuses to discuss his wife or her reaction to what he is doing. "I have dedicated my life to improving standards in the nuclear industry," he says, "and I have no intention of letting myself or my family be a subject of tabloid interest." A more measured, precise and emotionally continent individual would be hard to find. He presents calmly reasoned arguments for everything he does or believes in.

In the mid 1990s Voice and other volunteers at AEA Technology’s biomedical research laboratories in Harwell, Oxfordshire, took part in a series of trials lasting several years. The experiments tracked the movement of plutonium in blood, bone and internal organs. The main trials involved injecting six men and six women with radioactive isotopes of plutonium 237.

"Plutonium 237 is a short-lived isotope with a half-life of only 45 days," says Voice. "And because it emits X-rays its journey can be tracked from outside the body and scientists could follow what it was doing. This was the first time this had been done on live humans."

The results of the trials, published in the National Radiological Protection Board’s internal newsletter, showed that, in males, plutonium injected into the bloodstream accumulated in the liver, but didn’t lodge in either bone or reproductive organs.

Voice is one of two volunteers who have recently taken the experiments a stage further. Several times a year, he would travel to Harwell. There, in a sealed room, he would breathe in plutonium through an inhaler-type device straight into his lungs. "We have learned a lot about what plutonium does in the bloodstream," he says. "The vital link being made now is how it gets into the bloodstream in the first place."

Voice inhaled a mixture of two isotopes, plutonium 244 and plutonium 239, the type found in nuclear reactors. They are both alpha-emitters, the most dangerous type of plutonium for causing biological damage. Voice says he is not afraid of causing fatal damage to his body. Even if he has, he says he will be dead before he feels the effects. "Plutonium 244 has an enormous half-life - something like 80 million years - so it’s a very slow emitter. I don’t think I need worry too much about what could happen in the rest of my lifetime." The results of the latest trials, which are still being analysed, will provide information on absorption levels in the lungs, and the speed at which plutonium travels to the gut.

What it’s doing in there is not something Eric Voice dwells on. He doesn’t have time. He is now acting as a consultant in a UK project on the use of what he describes as "safe reactors" (which are gas-cooled) for future production of electricity. He also gives lectures and acts a climate expert for the Highland Council.

"We’ve been given this amazing resource for the good of mankind, not for destruction," he says.

As he flies between venues, it is doubtful he will be able to resist informing fellow passengers of their close proximity to 20 kilos of depleted uranium. "Why don’t people think about why it’s referred to as ‘depleted’? Because they prefer to listen to media hype, that’s why." The radioactive element has been removed, he says. Less than 0.7 per cent remains - less than in naturally occurring uranium.

"It’s really useful because its mass-to-volume ratio means it provides weight without taking up space. It’s used for rudder balance in aircraft. It’s used in the keel of yachts too and nobody bats an eyelid."

Howdy everyone,

   While I am awaiting a response to the fetal radiation situation, I will start the next class on the difference between natural background radiation and inhalation of 0.3 micron type particles of pu-238.

    The pro-nuke spin doctors from DOE like to compare inhaling plutonium from their incinerator and production facilities, to eating bananas. I bet some of you use that analogy too, because of the high energy natural potassium figure.

    While the potassium damage is unavoidable, (and delicious/nutritous,) it is an isolated single strike event, by a single potassium atom. If our natural repair mechanism fails, it can creat human health effects. Most damage is repaired well, and is usually only breaking one strand, of the 2 stranded DNA.

    The medical "theory", is that, the less DNA you break, the less chance the repair mechanism will fail. Especially in the rdiosensitive fetus, children, and elderly.

     The inhaled, potentially exhaled, potentially embedded pu-238 particle contains thousands of atoms, shredding out a continual pulse of alpha particles. The potential for double strand breaks, and another alpha strike BEFORE the first repair, is GREATLY increased. The CDC BS'rs used to confidently state " Don't worry, that kills the cells, and dead cells don't turn into cancer, only mutated cells can turn to cancer."  Bet y'all have heard that too. I always questioned that it was a total cell kill, but the dead cell statement is true, about not causing cancer, as far as we know today.

   But then came later these 2 wonderful studies from the National Academy of Sciences, by Dr Zhou. They isolate a SINGLE alpha strike, across a single cell! They show this creates a ten fold neighbor cell mutation!! Damn, the CDC pro-nuke know-it-alls may have been, ummm, very wrong...

 

Source:

1: Proc Natl Acad Sci U S A 2001 Dec 4;98(25):14410-14415
Books, LinkOut

Radiation risk to low fluences of alpha particles may be greater than we thought.

Zhou H, Suzuki M, Randers-Pehrson G, Vannais D, Chen G, Trosko JE, Waldren CA, Hei TK.

Center for Radiological Research, College of Physicians and Surgeons, and Environmental Health Sciences, School of Public Health, Columbia University, New York, NY 10032; Department of Radiological Health Science, Colorado State University, Fort Collins, CO 80523; and Department of Pediatrics/ Human Development, Michigan State University, East Lansing, MI 48824.

Based principally on the cancer incidence found in survivors of the atomic bombs dropped in Hiroshima and Nagasaki, the International Commission on Radiation Protection (ICRP) and the United States National Council on Radiation Protection and Measurements (NCRP) have recommended that estimates of cancer risk for low dose exposure be extrapolated from higher doses by using a linear, no-threshold model. This recommendation is based on the dogma that the DNA of the nucleus is the main target for radiation-induced genotoxicity and, as fewer cells are directly damaged, the deleterious effects of radiation proportionally decline. In this paper, we used a precision microbeam to target an exact fraction (either 100% or </=20%) of the cells in a confluent population and irradiated their nuclei with exactly one alpha particle each. We found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non-hit cells contributing significantly to the response. In fact, irradiation of 10% of a confluent mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. This effect was significantly eliminated in cells pretreated with a 1 mM dose of octanol, which inhibits gap junction-mediated intercellular communication, or in cells carrying a dominant negative connexin 43 vector. The data imply that the relevant target for radiation mutagenesis is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimates for low dose, high linear-energy-transfer (LET) radiation exposure.

PMID: 11734643 [PubMed - as supplied by publisher]

____________________________________________________

Published online before print February 11, 2000, 10.1073/pnas.030420797;
Proc. Natl. Acad. Sci. USA, Vol. 97, Issue 5, 2099-2104, February 29, 2000








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Cell Biology
Induction of a bystander mutagenic effect of alpha particles in mammalian cells

Hongning Zhou*, Gerhard Randers-Pehrson*, Charles A. Waldren, Diane Vannais, Eric J. Hall*, and Tom K. Hei*,,§

* Center for Radiological Research, College of Physicians and Surgeons, and  Environmental Health Sciences, School of Public Health, Columbia University, New York, NY 10032; and  Department of Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523

Edited by Richard B. Setlow, Brookhaven National Laboratory, Upton, NY, and approved December 10, 1999 (received for review October 1, 1999)

 
  Abstract



Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References

Ever since the discovery of X-rays was made by Röntgen more than a hundred years ago, it has always been accepted that the deleterious effects of ionizing radiation such as mutation and carcinogenesis are attributable mainly to direct damage to DNA. Although evidence based on microdosimetric estimation in support of a bystander effect appears to be consistent, direct proof of such extranuclear/extracellular effects are limited. Using a precision charged particle microbeam, we show here that irradiation of 20% of randomly selected AL cells with 20 alpha particles each results in a mutant fraction that is 3-fold higher than expected, assuming no bystander modulation effect. Furthermore, analysis by multiplex PCR shows that the types of mutants induced are significantly different from those of spontaneous origin. Pretreatment of cells with the radical scavenger DMSO had no effect on the mutagenic incidence. In contrast, cells pretreated with a 40 µM dose of lindane, which inhibits cell-cell communication, significantly decreased the mutant yield. The doses of DMSO and lindane used in these experiments are nontoxic and nonmutagenic. We further examined the mutagenic yield when 5-10% of randomly selected cells were irradiated with 20 alpha particles each. Results showed, likewise, a higher mutant yield than expected assuming no bystander effects. Our studies provide clear evidence that irradiated cells can induce a bystander mutagenic response in neighboring cells not directly traversed by alpha particles and that cell-cell communication process play a critical role in mediating the bystander phenomenon.

Mine was not a rhetorical question, but you identified your questions correctly. You provide a prime example of pro-nuke's love for comparing internal pu-238 exposure to a smoke detector that can be safely isolated on the ceiling. This is not the same, obviously. I use radioactive materials, and the Americium is old news in smoke detectors.

   The fact remains HEPA's leak, workers have accidents, as do space craft, rocket scientist make mistakes too. When citizens know the truth, the man on Mars before HEPA's work as well as claimed is a health threat, and about as farsighted in protecting human health as the FEMA/Bush (lack of) response to the 5 days of warning, of the impending class 5 Hurricane.

    I try to warn citizens and scientists. Most seem to understand...