Patterico's Pontifications

1/3/2007

Errors in L.A. Times Article About Litvinenko Killer Polonium-210

Filed under: Dog Trainer,General — Patterico @ 1:09 pm



In a comment thread at Cathy Seipp’s blog, a commenter named “doug” says:

The LAT has an oddly chatty piece on Polonium 210 which is remarkable in the sheer number of errors made. It looks like an amalgam of half baked internet stories that didn’t get run by a fact checker. It would be acceptable in some small rag somewhere but the Times should be better than that.

Polonium-210 is, of course, the radioactive isotope that killed ex-K.G.B. agent Alexander V. Litvinenko. You can read the article doug is talking about at this link. I’m no science expert — and I don’t know doug’s background — but he seems to have a point. For example, the article says:

Of polonium’s 25 isotopes, polonium-210 is the most stable. After 138 days, half of it decays into a nonradioactive isotope of lead.

That is the correct half-life for Polonium-210 — but it doesn’t make it the most stable isotope of Polonium. As Bradley J. Fikes (who tipped me to this) notes, Polonium-209 has a half-life of about 103 years — far longer than 138 days. There is at least one other isotope with a longer half-life. Fikes asks the obvious question: “How did this pass through the LA Times’ legendary four levels of editors?”

But that’s not all. The article also says:

It takes 10 half-lives — about three years — for all of it to be converted into lead.

To which doug replies:

“All of it” is not a phrase used to describe radioactive decay. Ten half lives just means that .1% of the original remains. Eleven half lives would be .05%. Twenty half lives would correspond to .0001%, and so on.

Once again, I think the man has a point.

“doug” points to a number of other alleged factual inaccuracies in the article, in this comment and this one. I’m unqualified to judge the accuracy of most of doug’s assertions, but if you have a science background, toddle on over and take a look.

I count six alleged errors, including the two mentioned above.

The Times may be headed for one of those comical corrections that goes on and on and on . . .

UPDATE: I added this sentence to the above for clarity: “That is the correct half-life for Polonium-210 — but it doesn’t make it the most stable isotope of Polonium.” Without that sentence, some people were misreading the post.

UPDATE x2: I changed “There are other isotopes with longer half-lives.” to “There is at least one other isotope with a longer half-life.” The reason is that I am not specifically aware of more than one.

19 Responses to “Errors in L.A. Times Article About Litvinenko Killer Polonium-210”

  1. Polonium-210 is not the same as Polonium-209. According to the link provided, the half life of Polonium-210 is 138.39 days. I’ll give the Times the 0.39 days, but the other points about the stability and “all of it” decaying are typical Times.

    We long ago cancelled for reasons like this, but my 15 month old daughter loves talking to the subscription dept on the phone at least once a week.

    [I think you missed the point, which is that 209 is more stable than 210. — P]

    Nick (75a292)

  2. P-co: “As Bradley J. Fikes (who tipped me to this) notes, Polonium-209 has a half-life of about 103 years — far longer than 138 days. There are other isotopes with longer half-lives.”

    “Other isotopes”? Try just one, Polonium 208, at least according to:

    http://en.wikipedia.org/wiki/Isotopes_of_polonium

    m.croche (85f703)

  3. Of polonium’s 25 isotopes, polonium-210 is the most stable. After 138 days, half of it decays into a nonradioactive isotope of lead.

    Uh, wouldn’t a “stable” isotope have an immensely long half-life (i.e., decay far less rapidly)?

    Dubya (c16726)

  4. In calculating a half life in a living organism ,the half life is a measure of the biologic half life (excretion time ) and decay time.Iodine 131 is the classic case.So the rate of excretion is a lot more important than the rate of decay,unless it’s a very rapidly decaying substance.
    (And ,boy ,it’s been a long time since p-chem)

    corwin (dfaf29)

  5. Dolt! The question was about the half-life of the isotope, not how long it took Litvenko to crap/piss it out.

    Dubya (c16726)

  6. Doug has his facts right. I was looking at my CRC Handbook of Chemistry and Physics before noticing Nick’s link (which LANL used the CRC as a reference).

    I don’t see it as willful errors on the part of the LA Times. I see it more as another example of how I define a journalist: Someone who knows little about anything trying to explain everything to everyone. Keep this in mind if you ever read an article or see a television news report on anything in your area of expertise. The chances are that the reporters/editors will oversimplify/misinterpret things to the point of distorting reality. That’s why I tend to view news with a jaundiced eye.

    Some Other Steve (SOS) (649c9f)

  7. The only science that matters at LAT is the “science” of global warming. That is probably their high-water mark of accuracy, everything else is a joke.

    Another Drew (758608)

  8. doug did not work out the half life correctly. after 3 half lifes there is .125 left. after 10 there is 0.0009765625 left. This is a small number but it is NOT zero.

    mathisgood (131180)

  9. Would anyone ever expect anything less from the SMELL A TIMES?

    krazy kagu (5fcc3d)

  10. mathisgood,
    .1% is the same as .0009765625 as rounded.

    [Right. I checked that math before I quoted it in the post. — P]

    doug (a25cfb)

  11. It takes 10 half-lives … for all of it to be converted into lead. This is a choice example of Times ignorance about the familiar law of exponential decay. As Patterico said, if you don’t understand it, you shouldn’t write about it. It would be so easy to fix the statement by saying, e. g., “After 10 half-lives, substantially all of it is converted into lead,” or some similar phrase.

    dchamil (affe79)

  12. Stable:
    Po-208: 2.93 years
    Po-209: 103 years
    Po-210: 138.4 days
    Unstable:
    Po-207 and below: 1s – 10 days
    Po-211 and above: 1us – 3s

    Source: CRC (1971), pp B489-B492

    Kevin Murphy (0b2493)

  13. By the way, the main reason that no one was looking for it is probably that there is VERY little Polonium in the world to be looked for. According to Wikipedia less that 100 grams are made artificially worldwide. Due to the short half-life, little exists in nature.

    Now, this also makes the use of Polonium rather uncasual.

    Kevin Murphy (0b2493)

  14. Murph:

    Stable:
    Po-208: 2.93 years
    Po-209: 103 years
    Po-210: 138.4 days
    Unstable:
    Po-207 and below: 1s – 10 days
    Po-211 and above: 1us – 3s

    Source: CRC (1971), pp B489-B492

    Now I really don’t understand that! Maybe a definition of what “stable” means in the context of isotopes would end the confusion. Can you provide a reference link?

    It seems self-evident that something that does not transform quickly into something else is “stable” whereas something which transforms essentially completely in less than 4 years seems “unstable.”

    Dubya (c16726)

  15. As to the descriptor “stable”–used in an absolute sense, only nonradioactive isotopes qualify. Today’s 1 gram of carbon-12 will be 1 gram of carbon-12 as our universe winds down (provided you keep it out of a nuclear reactor or a star’s core)–that’s stable.

    However, people working with radioactivity use the word “stable” to mean “stable relative to the other isotopes we deal with.” So to a geologist using uranium-238 (half-life 4.5 billion years) to date rocks, carbon-14 (half-life 5700 years) is unstable, but to a molecular biologist labeling DNA with phosphorus-33 (half-life 25 days), carbon-14 is stable.

    The likely source of

    It takes 10 half-lives — about three years — for all of it to be converted into lead.

    is a misapprehension of what’s taught in radiation safety classes. NRC regulations allow university licensees to consider small quantities of most commonly-used, short-lived isotopes to be treated as if they are no longer radioactive, provided that they are first held in secure storage for ten half-lives.

    This was never meant to be taken as a scientifically correct description of the nature of radioactive decay–it’s simply a practical guideline. And one that no licensee would apply to a large quantity of a hazardous isotope like polonium-210 (at least not more than once…).

    I suspect if the reporter had talked a little longer with his/her sources, these points would have been made clear.

    –A former laboratory Radiation Safety Officer and fission-track rock dater

    AMac (42d8ce)

  16. Dubya–

    To me, a stable substance is one that can occur in nature and stay around long enough to be noticed. Of the ones I mentioned as unstable, only one or two last longer than a few hours, and most last tiny fractions of a second.

    Obviously, you could say that no radioactive element is “stable” if you wanted.

    Kevin Murphy (805c5b)

  17. Obviously, you could say that no radioactive element is “stable” if you wanted.

    Which is what all of those I know of (speaking as someone who’s handled substantial quantities of the various transuranics) do. We occasionally describe them in terms of *relative* stability but we don’t call radioactive isotopes stable. And we especially don’t draw an arbitrary line the various Po isotopes. They all have high activities on a weight basis.

    Additional Blond Agent (9315f5)

  18. KFI’s JOhn and Ken are today reading the LA Dog Trainer version of a “former” gang family’s turnaround and the real story as told by recent LA Weekly story. Hot stuff!

    Patricia (824fa1)

  19. […] Courtesy of Cathy’s World commenters “doug” and Bradley J. Fikes, I told you about these errors on January 3. […]

    Patterico’s Pontifications » L.A. Times Corrects Errors in Article About Litvinenko Killer Polonium-210 (421107)


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