Talk:Plutonium

Plutonium is by no stretch of the imagination the most dangerous substance known to man. It will give you cancer if you inhale plutonium dust but that's true for all alpha emiters, and in any event that won't kill you for a few decades.

Also removed the stuff about radiological bombs, because plutonium isn't very radioactive (and because it is hard to get), it's not a particularly good material for a dirty bomb especially in comparison with radioactive iodine or cesium.

Well, what IS the most dangerous substance known to man, then, if it's not plutonium? Graft

Off hand, it's guess that maybe a nerve agent like sarin. Also, one could argue that refined plutonium *is* one of the most dangerous substances known to man, not because of its inherent lethality, but because you can build bombs with it and you don't want the stuff lying around where bad people can get it.

So, apparently VX has an LD-50 lower than sarin, of .008 mg/kg. Ricin does better at .001 mg/kg. By far the best is the famed botulinum toxin ('botox') at 200 pg/kg. Yow. I remember reading that one molecule of botulinum toxin is sufficient to kill a cell. Graft

Just on the logic above, about plutonium being the most dangerous substance because you can build bombs with it, that would probably make steel the most "dangerous" substance of all. You can build an a-bomb without plute, but you can't build one without steel. Nor can you build rifles, tanks or warships. Let's remember we're writing an encyclopedia article here. This sort of thing does not belong. Andrewa 11:46 Mar 8, 2003 (UTC)

Regardless of what the most dangerous substance is, it's certainly not Plutonium. Naturally-occuring Radium is about 200 times more radiotoxic. Andrewa 23:31 Mar 7, 2003 (UTC)

I don't remember specific LD-50 data, but plutonium salts are among the most toxic of all inorganic substances. N.B. that's chemical toxicity, not radiotoxicity. Mkweise 00:01 Mar 8, 2003 (UTC)

LD50 (http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/L/LD50) data can't by definition be used to separate chemical and radiological toxicity, it is a measure of the overall effect of the substance. So whatever the source of this information, I'd double-check that you understood them. The other strange thing about this claim is, why focus on inorganics? The organic compounds (which include of course organic salts) of heavy metals (eg lead) are normally the most deadly. Is there any reason for thinking plutonium won't be the same? It will be difficult to find out, as the radiotoxicity is high enough to mask these effects anyway. Plutonium is very nasty stuff. But not as nasty as some people want to make you think. Andrewa 11:46 Mar 8, 2003 (UTC)

My source on that is a nuclear war preparedness manual, ca. 1979, which was handed out to my class back in high school - so it is possible that it's exaggerated. It clearly states that unlike uranium, plutonium kills by (chemical) poisoning long before its radioactivity gets anywhere near dangerous levels.

Not wanting to be unkind, but this sounds like a political document. Do you remember who wrote and printed it?

The nasty thing about inorganic toxins is that they accumulate over a lifetime as well as up the food chain. (N.B. organic acid salts of heavy metals are considered inorganic toxins, since the toxic ions are inorganic.) Organic toxins, while dangerous in much lower doses, generally (with a few notable exceptions like dioxins) biodegrade very rapidly, often in a matter of days or even hours. Mkweise 03:08 Mar 11, 2003 (UTC)

Four problems here. One, the claim was about "inorganic substances", and these don't include organic salts regardless of what "inorganic toxins" might mean. So can we lay that one to rest? Two, some organic salts aren't "organic acid salts", as many metals such as plutonium, uranium and aluminium are amphoteric. Three, some salts[?] (not many but some, and it depends a bit on the definition of a salt which is a bit controversial on this exact issue) don't ionise in food or in the body since they are not soluble in water. Four, it's not obvious what all of this is supposed to prove.

Obviously this is a complex and controversial subject, and there's a lot of misinformation and guesswork in existing literature. Beware! Andrewa 20:44 Mar 11, 2003 (UTC)

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I see the bit about radiological bombs has been put back in. I'm not going to remove it, for the moment at least. I think it would be good if someone a bit closer to politically neutral on the issue had a look at it.

More serious I think is the claim about first aid on the Manhatten project. It sounds like an urban myth to me, and I think it's put there to scare people. But it may be true, funny and horrible things happen in wartime. I have no evidence either way, so again I have not touched it. But maybe someone should. Andrewa 23:51 Mar 7, 2003 (UTC)

In the late 1940s a secret project was initiated to evaluate the toxicity of Plutonium and where it concentrated by injecting "Terminally Ill" patients with various amounts of Plutonium salts solutions. Usually the injected limb was amputated within a few weeks and analyzed for distribution of the Plutonium. As these were "Terminally Ill" patients, none were expected to survive more than a few years at most. However a small number of these patients did recover from their original illness, and with no significant obvious problems due to the Plutonium. At least one of these patients was still alive in the late 1980s!!! -- RTC 00:05 Mar 8, 2003 (UTC)

That would give a possible source of this myth, if myth it be. But it doesn't answer the basic question of whether there is some truth in it. I doubt it belongs in the article, myself. Andrewa 11:46 Mar 8, 2003 (UTC)

I agree, true or false, the part about "amputation" does not belong and the proper context of the toxicity data should be made. -- RTC 00:39 Mar 11, 2003 (UTC)

Quoting from http://www.oism.org/cdp/V10_05.htm (http://www.oism.org/cdp/V10_05.htm):

The most toxic substances known to man are made by bacteria. Contrary to allegations by PSR, et al., plutonium is ``not a world-class toxicant, writes T. Don Luckey in a June 20 letter to Chemical and Engineering News. When injected intraperitoneally into mice, the LD50 (the dose that causes 50% deaths in 30 days) is about the same as that of the vitamin pantothenic acid.

On a scale in which plutonium has a toxicity = 1, the toxicities of other materials are:

• mercury chloride 100
• strychnine 1,000
• actinomycin D 10,000
• tetrodotoxin 100,000
• perfringens A toxin 1,000,000
• pestis toxin 10,000,000
• shigella toxin 100,000,000
• botulinal E toxin 1,000,000,000
• tetanus toxin 100,000,000,000
• botulinal B toxin 1,000,000,000,000
• botulinal D toxin 10,000,000,000,000

The EPA is more concerned about carcinogens than toxins, but plutonium doesn't make the grade there either. Plutonium-contaminated workers have a lower total cancer mortality: 88% that of unexposed workers.

End quotation -- RTC 00:40 Mar 8, 2003 (UTC)

Is that right? That's surely the result of poor statistics... otherwise you're saying that working with plutonium can help -prevent- dying of cancer. Graft

I suspect the reason for the reduction in mortality is that their employers monitor their health much more closely, so cancers in these workers are usually caught at much earlier and more treatable stages. However that is only a guess. -- RTC 22:32 Mar 11, 2003 (UTC)

Check out the article on radiation, and the new section on radiation hormesis. This is just a hypothesis, but exposure to small amounts of ionizing radiation may actually reduce the risk of cancer. RK

I read it, and it's bullshit. The argument against linear no-threshold dose-response completely misunderstands the two-hit model for cancer generation and doesn't even begin to challenge it. Graft

Have you any reasons for thinking hormesis and the two-hit model (I assume you mean Knudson’s work here) aren't compatible? They answer quite different questions. Perhaps this discussion should go to Talk:Radiation. Andrewa 18:33 Mar 14, 2003 (UTC)

I think what is important is that we try to come to a consensus as to what the key facts are, and what they key opinions are, and try to describe all of these in a readable and approachable way that makes it clear which is which.

I've had go! I'm not completely happy with the results but I'm sure they won't last too long! And I think we are making real progress.

The key question I think is what is "danger" and what is "toxicity". "Toxicity" can be measured and is a matter of fact. "Danger" is felt and is a matter of opinion. Does this help? I have not been consistent in this usage myself I realise. Andrewa 00:24 Mar 12, 2003 (UTC)

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This set off my BS meter. Moving to talk until/unless someone can list a citation for this.

According to some accounts, the accepted first aid technique for tissue exposure to plutonium during the Manhattan Project was immediate high amputation of the exposed limb. This is unlikely, as the focus of the Manhatten Project was the wartime development of an important weapon and industrial safety was not a high priority. The dangers of other key materials, such as beryllium, were not researched and documented until many years afterwards.

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Rewrote. The toxicity of plutonium really isn't a "controversial topic." I don't know of anyone knowledgeable either in the anti-nuclear movement or outside that will seriously defend a statement that plutonium is magically toxic.

Good rewrite. I'm still concerned that we've gone back to saying the plutonium is a "particularly deadly poison" when the evidence is that nobody ever has or ever will suffer such a fate, and that we've gone back to calling plute weapons a "category" when in fact non-plute weapons have always been rare exceptions, and that we're back to suggesting that plute might be useful as a radiological weapon, when if you blew up some spent nuclear fuel for example the fission products would be a much bigger problem than the plute. But we've made great progress on what the article said just a little while ago. Andrewa 02:27 Mar 12, 2003 (UTC)

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Because of its low half-life, there are only extremely tiny trace amounts of plutonium naturally.

Someone more knowledgable than I - I've been given to understand that transuranium elements simply don't occur at all naturally. Is this just a convenient oversimplification for the layperson? Is the above statement accurate? Graft

It does occur in uranium ores, due to occasional neutron capture by U-238 followed by decay to Np-239 and Pu-239. But as these events are VERY infrequent (they depend on spontanious fission rate of U-235 as well as neutron capture cross section of U-238) compared to the half-life of Pu-239, the levels can be practically ignored. I don't remember exact figures, but as I understand it the total amount of "naturally occuring" Plutonium in the entire earth is measureable in micro-gram quantities. The amount mankind has manufactured in reactors is many tons. -- RTC 02:30 Mar 14, 2003 (UTC)

The explanation is that as analytical techniques improve, previously undetectable quantities become detectable. I don't think there's any proposal to change the status of plutonium to "natural" rather than "artificial", but that's only one of several reasons that this distinction has now blurred a little. Two others are the recognition that plutonium was once more common on earth than it is now, and the discovery of natural "fossil reactor (http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/index.shtml)" sites in Gabon. Andrewa 17:20 Mar 14, 2003 (UTC)

Actually, any plutonium detected by "analytical techniques" is almost certainly contamination from unfissioned plutonium in the fallout from the 1940s through 1960s bomb tests. Even in modern uranium ores (as far as I know) the "naturally occuring" levels are estimates based on spontanious fission rates, capture cross sections, and decay rates. -- RTC 19:09 Mar 17, 2003 (UTC)

Webelements says "Plutonium is found in trace quantities in uranium ores but, in practice, normally it is synthesised by the transmutation of uranium. However, it is now found in very small quantities in some areas as a result of fallout from atomic bombs and from radiation leaks from nuclear facilities." I thought that mass spectrometers were now sensitive enough to detect the plutonium in uranium ores, but I could be wrong. This would not be contamination if so, as there hasn't yet been time for man-made plute to invade the geology to this extent. Andrewa 21:25 Mar 17, 2003 (UTC)