I think you fellows should back off a little; your dogmatic certainty is unbecoming.

Almost anything that one can find about the absorption of Po210 in the gut indicates that it is very inefficiently transported across membranes when it is in the form of dissolved solids or salts. Most of the research on contamination (studies on rats, etc.), deals with inhalation, not ingestion, just as Large says.

I think you guys are just getting a rush from feeling that you have caught an "expert" with his pants down. That is understandable. But it strikes me as unlikely in the extreme that someone with Large's resume would be guilty of errors as egregious as those he is being charged here with making.

The crucial fact here might be whether or not Salon is in error when it reports that Large ". . . spent some 20 years as a research fellow with the British government's Atomic Energy Authority before starting his own firm, Large & Associates, where, among other things, he was responsible for risk analysis during the salvage of the sunken Russian nuclear submarine Kursk." If this is accurate (and I have no reason to doubt that it is), then I think it would be fair to assume that the man knows what he is talking about.

I don't personally claim expertise in the area of radio-nuclide dosing, and dosimetry. That is an arcane field of very specialized knowledge. (I do know something of radio-dosimetry, which knowldge was absorbed in my early years as an analytical spectroscopist; experience that includes high-energy X-Ray and other techniques.) I am only suggesting here-- humbly, I hope-- that, lacking such expertise as Large plainly possesses, the posters should be a little more conservative in their criticisms.

Given that there is considerable doubt as to whether you guys actually know what you seem to want to claim to know, maybe you should be a little more conservative, a little less certain .

"A little learning is a dangerous thing, drink deeply from the Empyrean Spring . . ."

I'm more than happy to stand corrected. I've learned at least half of what I know by finding out that I was initially wrong. I also have no interest in humiliating or one-upping anyone. (Your insinuation that this is my motive is kind of a cheap shot).

I stand by my statement concerning the availability of polonium 210. This substance is not harder to come by than, say, key reagents used in the manufacture of illicit drugs.

My speculation about the use of a halide compound was just that: a speculation. I indicated this by framing my statement as a "guess". Sounds like you know more about this than I do, and I have no problem saying so. Still, Large's speculation that some form of exotic nanotechnology is required to explain this incident strikes me as being unparsimonious. He could turn out to be right. (It would be more interesting, actually, if he did). But, at this point, I would put my money on something far more prosaic. It will be interesting to find out.

Having stated as much, I return to the real intent of my previous post, which is neither to flaunt expertise that I do not possess, nor to denigrate an expert for kicks, but to suggest that Salon improve the quality of its science reporting. Salon should have handed this assignment to a science reporter, should have consulted more than one expert, and should have vetted this story more carefully before affixing it prominently beneath its masthead. Salon does an excellent job in other areas, and ought to do an equally excellent job in this area. I offer these thoughts as constructive criticism in the hope that they will be of some use.

Yes, you can buy Polonium 210 readily on the internet. Here's one site who sells it for $69:

http://www.unitednuclear.com/isotopes.htm

The thing is, this is a tiny amount, used for testing radioactivity meters. By their estimates, you need to buy 15,000 of their kits to have a good chance of poisoning someone. And it would be technically very difficult to extract the polonium from 15,000 electroplated needles, and recombine it into a whole.

The only people who had the technological skill to pull off this poisoning are to be found among the nuclear powers, and probably only one or two of them at that.

Just to clarify, I never suggested that the culprits in this case extracted polonium from brushes (or any other end-use product containing polonium); but that, if the brush manufacturers can obtain enough polonium to make a go of it, then anybody else could obtain material in quantity from the same sources.

Back in the day, Stan Owsley was able to purchase large quantities of mescaline from legitimate suppliers by setting up a fake lab. He even hosted federal inspectors in his lab, and got away with it. This sort of thing would, I think, be even easier to pull off in Russia, a nation many of whose bureaucrats rely on graft for their livelihoods.

The only people who had the technological skill to pull off this poisoning are to be found among the nuclear powers, and probably only one or two of them at that.

This is why this matters, isn't it? I dispute this. Litvinenko's killers could have purchased their material from a lab or a company, or from a large number of small sources. They could have bought it from a corruptible employee at a nuclear power plant. They could have devised a simple and effective delivery system, and done their murder.

The participation of a state actor is not required to explain this case. It is not yet possible to rule out a plot by rogue actors. It may still turn out that Putin did it. On the other hand, it may not.

Here's an example of how the American press tries to sanitize the nasty corrupt stinking Yukos affair:

But Mr. Litvinenko nonetheless displayed a knack for confidential business. According to a report in The Times of London in November, he traveled to Israel weeks before he died to hand over a dossier on the Yukos oil affair — in which the company’s former chairman, Mikhail B. Khodorkovsky, has been imprisoned for tax evasion — to Leonid Nevzlin, an exiled oil tycoon.

Not one word about Pichugin serving 20 years for locking the Gorin children in a closet and making them listen to their parents being murdered.

And not one word about Pichugin claiming Nevzlin ordered him to do it.

And they left out the part where Nevzlin ran to Israel to avoid being prosecuted for his role in those murders.

Why does the American press feel so compelled to sanitize the Yukos crowd and leave the murder charges from their resumes?

I remember reading the Moscow Times in the nineties and seeing murder after murder in the news, and most of them happened to benefit Menatep or Yukos. I bet the poor Gorins are just the tip of the bloody iceberg.

I don't usually pay attention to Russian claims of bias but this one is hard to ignore.

I wonder -- how many, and which, Americans lost money on Yukos when Putin broke up the company?

Watch "Spinning Boris." At least part of this murky story begins there.

BY THE WAY -- when I started thinking on the "what if Khodorkovsky were behind this?" line -- I HAD NO IDEA Litvinenko had actually been to Israel to SEE Nevzlin a few weeks before he was killed.