Well, what is "the truth about depleted uranium"? I know a thing or two about the physics of radioactive decay, and one thing I do know is that depleted uranium is hardly worth bothering about as a source of radiation. Any risks posed by DU are more likely to stem from the fact that it is a heavy metal, rather than the ominous notions that the word "uranium" seems to inspire in many souls on the web.

The findings of the very World Health Organization cited above as an authorititative source of information would seem to corroborate my opinion as to the (non) significance of DU as an environmental threat. Chalk at least one up for blogosphere opinion in this case.

Yes, a weak alpha source, isn't it? Stopped by a kleenex, pretty much. Hardly worth bothering about... unless it's finely powdered and, for instance, embedded in your lungs. As tends to happen to DU used to blow up a tank.

Did you even bother to read the report before uttering this bit of propaganda? Need I point out that if you are in the vicinity of a tank that is firing a DU shell, you might have more pressing matters to worry about than dust from DU? Or that, being a heavy metal, aerosolized DU would hardly stay in circulation for very long?

Has anyone heard *anything* from or about John Marburger, the president's science advisor, since . . . well, ever?

Marburger, an actual scientist and former president of my undergrad college, was hired in early summer 2001 . . . reportedly to counter charges that the administration was overly conservative.

The silence is almost eerie . . . is he locked up somewhere? Does he spend his days composing memos to Bush that instead end up in Karl Rove's shredder?

Broken link on "dilates". The value for the HREF attribute has a single-quote at the beginning and a double-quote at the end. And it's got a plus sign instead of equals. Most scientific!

Quant Suff!

being a heavy metal, aerosolized DU would hardly stay in circulation for very long?

Er, and... so then what happens to the fine powder? It magically dematerializes? ...Or does it fall to the ground, to get on shoes and hands and faces, to be blown about by sandstorms and breathed in, to be tracked into houses, to get into food...

DU is a very weak emitter of radiation, but it effectively stays radioactive forever, in terms of human lifetimes. Once you've distributed copious quantities of finely pulverized DU into an environment, good luck living in that place without getting some of it lodged inside your body in direct contact with living tissue.

Asbestos isn't radioactive at all, it's only a fibrous rock, but there's a reason they don't use it for house insulation any more.

>being a heavy metal, aerosolized DU would hardly stay in circulation for very long?

Er, and... so then what happens to the fine powder? It magically dematerializes? ...Or does it fall to the ground, to get on shoes and hands and faces, to be blown about by sandstorms and breathed in, to be tracked into houses, to get into food...

By and large, it falls to the ground and just stays there. It's too heavy to be blown around very much (and just how many people go wandering around in a sandstorm anyway?), it's insoluble, and it's not picked up by plants.

DU is a very weak emitter of radiation, but it effectively stays radioactive forever, in terms of human lifetimes. Once you've distributed copious quantities of finely pulverized DU into an environment, good luck living in that place without getting some of it lodged inside your body in direct contact with living tissue.

"Very weak" is an understatement; it has a half life of 4.5 billion years. Less than a hundred-millionth of it will decay in a human lifetime. Unless you sniff piles of DU powder like snuff, its lifetime dose to you is going to be tiny compared to your dose from cosmic rays, potassium-40, and (depending on where you live) naturally-occuring radon. (Incidentally, radon comes from the decay of the uranium and other isotopes distributed throughout the Earth's crust, whose total quantity is many, many orders of magnitude more than the amount of DU humanity has ever produced. Even if you don't live in a house with a high radon concentration, you probably get more dose from radon than you would from a few micrograms of inhaled DU dust.)

Asbestos isn't radioactive at all, it's only a fibrous rock, but there's a reason they don't use it for house insulation any more.

Yes, asbestos is directly carcinogenic, and far more viciously so than DU, as well as being much easier to get and keep airborne. (And probably overblown as a hazard to non-industry workers as well, although that's another story entirely).

When you say "isn't radioactive at all" you show clearly that you've bought into the utterly baseless belief that radioactivity, in and of itself, is somehow more horrible than chemical toxicity or any other insult to the body. And many kinds of toxic chemicals are toxic forever and ever -- they don't even *have* half lives. Instead of getting worked up about depleted uranium, why don't you get worked up about beryllium, cadmium, and selenium, all of which are highly toxic, and all of which are manufactured in large quantities and disposed of casually all the time. Or have you never tossed a NiCad battery or an old TV set into the trash??

Sorry about the rant, but I get very, very tired of people demonizing radioactivity.

Jordin Kare

Abiola, maybe we read a different WHO report? The one I read that Patrick linked to says that DU can be a health hazard, if ingested in sufficient quantities, but tests around Kosovo suggested that there was insufficient DU there to be a significant health hazard. For obvious reasons, no such tests have yet been carried out in Iraq: until they have been, I maintain an open mind as to whether there DU constituted/constitutes a health hazard in Iraq after the 1991 Gulf War.

"Abiola, maybe we read a different WHO report?"

If you did, where is it? I showed you mine, so you might as well show me yours. I suspect that you didn't read any such report, and simply want to pass off your own groundless paranoia about depleted uranium as some sort of scientifically-founded opinion.

I read this report, Abiola, which now I check is the same one you linked to. I'm not at all clear how you can be sure, after reading it, that DU presents no health concern whatsoever, since I got no such definite message from it. I don't think it's scientific to be certain in advance of the data, and as yet we have insufficient data about DU exposure in Iraq.

Back in May, Northrup complained about the stupidity of the DU stories he could find. He was pretty skeptical about the hysterical scare stories, but more importantly stressed that investigations like this one don't say a damn thing either way.

Jordin, I am the daughter of a nuclear physicist. The word "cyclotron" was an ordinary part of my vocabulary when I was three years old. I handled a lump of pitchblende when I was five. I think nuclear power is a fine idea. I most certainly have not bought into the exaggerated "scare stories" about radioactivity.

I was raised, however, to take reasonable precautions around radioactive substances, and I know that having any radioactive material lodged permanently in your tissues is many times worse, risk-wise, than being in the same room with the stuff.

By and large, it falls to the ground and just stays there.

Doesn't that depend a whole lot on the particle size? I don't suppose a fist-sized chunk of DU is any danger at all. It's probably pretty much okay even if the particles are like beach sand, because uranium is so dense. If the munitions exploding grind the DU to flour, though, that's another story. They have sandstorms in Iraq the way other places have hurricanes or typhoons, storms that can move whole mountains of sand. And it's not like houses in Iraq are generally airtight. A sufficiently fine DU powder... well, it's going to be really hard to avoid breathing some of it in. So, while I'm not pressing any panic buttons, I *am* saying that it is going way, way beyond the evidence to assert confidently that DU weaponry presents no danger to people trying to live in the region after the battle.

My asbestos comment was made to point out that tiny particles of supposedly harmless stuff (which asbestos was thought to be when it was used so extensively as insulation) have a way of getting into everything, once you allow them into the environment. It took decades, and a lot of deaths, to establish that asbestos was carcinogenic. In fact, it turned out that the specific particle size had a lot to do with how dangerous it was. DU is a heavy metal; intimate contact with it is likely to be somewhat bad for you even apart from its radioactivity.

As for the other elements you mention, I assure you that I would be equally opposed to an operation that ground any of them into a fine powder and strewed it about at random. I repeat, I'm not screeching "Horrors, horrors, RADIOACTIVITY!" I'm just saying that it is way premature to go around saying DU rounds are not a hazard. There are reasonable grounds for suspecting they might be, there is a powerful interest group saying very loudly that they are perfectly safe, and I remember that asbestos was once supposed to be inert, too. I want the research to be done, is all.

Anyway, I'm not looking for a fight -- I imagine I must have inadvertently used a keyword or two that set off a prepared rant against a position I do not occupy.

It does seem as if a few people have, ahem, kind of missed the point of Northrup's ironic rant.

On a different subject, without expressing any opinion on the toxicity of depleted uranium, I would observe to the very sensible Jordin Kare that if people are frequently irrationally suspicious of "radiation," it may have something to do with the fact that for many years in the middle of the 20th century, government and industry lied to the public consistently, constantly, and shamelessly about it.

Abiola knows everything about everything always and forever. Duh. I prefer to try to learn.

Sylvia Li

My "instinct" as a physician is that I sure would not want to be anywhere around a windy dusty area with detectable amounts of depleted uranium. Asbestos IS horrid stuff!

Sylvia: Thanks for a reasoned response. I'm a physicist and I've worked at nuclear labs (Berkeley and Livermore) but I think you have me beat on the age at which I started using the word "cyclotron."

With rant mode off, I'd certainly agree there's likely to be a nonzero amount of DU that makes it into houses, and even into lungs; my point is that the actual damage that will do is probably small -- not zero, but tiny compared to other things,including the casualties of the battles in which the DU was fired. As usual, there's a huge gray area between "It's perfectly harmless" and "It'll render vast tracts of land uninhabitable forever" Alas, most spokespeople seem to insist on one extreme or the other, and my apologies for interpreting your remarks as advocating one extreme.

As far as dust on the ground, yes, size does matter, but my understanding is that it's hard to get uranium (actually UO2, since it oxidizes easily) into a particle size range that's likely to stay airborne and be inhaled. Pu is a somewhat different problem, since it does tend to turn into fine-particle "smoke" when it combusts, and it's significantly more radioactive (though it's still not nearly "the most toxic substance known to Man" as news reports seem to insist on describing it).

I definitely agree that DU is a heavy-metal toxin and that it should be treated with care. Battlefield cleanup is just one of the things the U.S. is falling down on in its military adventures (and anyone who lets US troops do cleanup without good filter masks should be court-martialed). I'm all in favor of more research on its long-term effects. It's the use of radioactivity as a bogeyman that I object to.

Patrick: You make a good point -- the nuclear industry did a really thorough job of destroying its own credibilty, and I'm repeatedly amazed at the sheer stupidity of the nuclear power industry in particular.

I have to say, though, that in my experience, and in what research I've seen, many peoples' fears of nuclear power and radiation are not rational. I started to say that they were as irrational as belief in astrology or fear of witchcraft, but that's not true; there are real risks. But peoples' ability to weigh risks (and to judge credibility of spokespeople) seems to go out the window when the word "nuclear" is mentioned.

I've noticed that when I say "I'm keeping an open mind on the subject" with reference to the possible health hazard of DU in Iraq, people tend to assume that that means I'm more ignorant than they are, because they know what to believe. Actually, it means I'm just as ignorant as they are, but I'm aware of it.

I think you're seeing an instance of a more general truth, Jordin. People (and I include myself) are just no good at judging an unfamiliar risk. The first response seems to be to ignore it altogether, pretend it's not a risk at all. If something pushes the risk over a certain recognition threshold, the automatic reaction is to enormously overestimate the danger.

(It's a rock, it's a rock, it's only a funny-shaped rock, it... ohmigod it MOVED, it's a SABRE-TOOTHED TIGER, GAH, RUNRUNRUN FOR YOUR LIVES!!!!!) I suppose, amongst early humans, the ones who took the time to go through "Oh, maybe it's a plant blowing in the wind, no, wait, it could be a bunny-rabbit... too big, it might be a deer, no, maybe a sloth... a baby mammoth...?" didn't on average live to reproduce quite as often.

Once it's a familiar risk, especially once people have established some coping strategies, the response level goes back down, and quite high risks are often accepted matter-of-factly. This pattern seems to appear for everything from global warming to auto accidents.

The remarkable thing is that the alarm level generally correlates very poorly with the actual risk.

Sylvia: There have been many studies of how we perceive risk; dunno if your hypothesis about the origin of our perceptions is valid, but your conclusion agrees with the studies. Risks are weighed more heavily if they're catastrophic, unfamiliar, involuntary, and "dread" (frightening to contemplate, like cancer or sitting in a falling airplane). A quick google shows a more extensive tabulation of factors here
Nuclear power plant accidents and nuclear weapons score high on almost all factors.

Oddly, radioactivity *by itself* (and even nuclear waste disposal) shouldn't rate all that high -- everyone with a tritium-dial (or, once, radium-dial) watch is at least a little familiar with radioactivity, its effects are not likely to be catastrophic, the mechanisms of damage are pretty well understood and known to science, and so on. (OK, its most likely effect -- cancer -- is widely dreaded) So I tend to regard "fear of radioactivity" as a peculiar and artificially-generated artifact of our culture, whereas, say, "fear of nuclear power plants" is unsurprising, and "fear of nuclear weapons" is downright rational. (If you want to be really scared, look into how disassembly of obsolete nuclear warheads is done in this country. How it's being done in the former Soviet Union, I shudder to contemplate.)

Patrick: I take it you were thinking of discussion more along the following lines?

"In the Middle Ages people believed that the earth was flat, for which they had at least the evidence of their senses: we believe it to be round, not because as many as one per cent of us could give the physical reasons for so quaint a belief, but because modern science has convinced us that nothing that is obvious is true, and that everything that is magical, improbable, extraordinary, gigantic, microscopic, heartless, or outrageous is scientific.

"I must not, by the way, be taken as implying that the earth is flat, or that all or any of our amazing credulities are delusions or impostures. I am only defending my own age against the charge of being less imaginative than the Middle Ages. I affirm that the nineteenth century, and still more the twentieth, can knock the fifteenth into a cocked hat in point of susceptibility to marvels and saints and prophets and magicians and monsters and fairy tales of all kinds."

— George Bernard Shaw in the preface of "Saint Joan"

Admittedly, Shaw has a different slant on this than Andrew, one which is open to some criticism, but his points about faith and credulity in modern times are still well-taken.

(And my apologies for recycling more thoughts by others today than providing ones of my own; I blame it on my busy schedule.)

I have to say, though, that in my experience, and in what research I've seen, many peoples' fears of nuclear power and radiation are not rational. I started to say that they were as irrational as belief in astrology or fear of witchcraft, but that's not true; there are real risks. But peoples' ability to weigh risks (and to judge credibility of spokespeople) seems to go out the window when the word "nuclear" is mentioned.

Indeed.
One need look no farther than the wonderfully useful technique of Nuclear Magnetic Resonance (NMR), a standard tool used by thousands of chemists and physicists, which became plain old Magnetic Resonance Imaging (MRI) when it started to be used for medical purposes, lest the N-word scare people off.

The reactor on which I used to be licensed had a pretty little doodah from the 1920s that neatly lowered a lump of radium into your morning orange-juice. Radium was Modern and Scientific, and therefore healthy...

To the peculiar danger-response thresholds described above, I would add a modern assumption that any scientific advance will be either vital or lethal. I don't know if this assumption is based on headline stories' exaggerated views, or on some inheritance from Aristotelian drama.

You know, if I had a penny for every time I've heard the NMR/MRI story from a physicist....

Not that there's anything wrong with it, I guess. It's just one of those things that I sort of wish were an urban legend because I hear it so damn often.

(Actually, sometimes, for some people -- I'm not speaking of anyone here -- there is something wrong with it. It's generally used to dismiss the fears of the public in a disdainful, "aren't they so very stupid", manner. This sort of confusion of ignorance and stupidity is an easy trap that some scientists fall into -- moi? never -- and it's certainly not a great way to make friends.)

There usually are unexpected risks with heavy metals, though. Think of mercury. It was not at all obvious that there would be bacteria that would transform it into methyl mercury, and that that would turn into a toxic waste problem, still less that it would turn out to concentrate in fish, of all places, in levels sufficient to be a human health hazard.

Uranium, it turns out, has a soluble sulfate; I would expect that to be formed in any area with significant SO2 pollution. There are organisms that metabolize it; I found an article on bioremediation of mine tailings. I don't trust the stuff, no, not at all. Most heavy metals, even very common ones, have turned out to be hazardous in unexpected ways. I don't know that uranium used in shell casings is an especially problematic one...but I don't know that it isn't, either, and I'm not sanguine about the risks.

Oddly, radioactivity *by itself* (and even nuclear waste disposal) shouldn't rate all that high -- everyone with a tritium-dial (or, once, radium-dial) watch is at least a little familiar with radioactivity, its effects are not likely to be catastrophic, the mechanisms of damage are pretty well understood and known to science, and so on.

Well, that depends who you are. A radium-dial watch is utterly safe - unless you're one of the women who was employed to paint the radium figures on. A locked door is harmless - unless you're on the other side of it during a fire.

Certainly in the UK, many people assume the government is lying about radiation hazards when they say they are not significant because in the past, the government lied about radiation and other hazards, saying they were not significant when they turned out to be highly dangerous. And as any government employs many people who can loosely be described as "scientists", any government statement saying that a hazard is not a hazard can easily include "Scientist Jo Smith says"...

Another difference between "Nuclear Magnetic Resonance" and "Magnetic Resonance Imaging" in a medical context, other than that the first one contains that scary word "nuclear" and the second one doesn't, is that the second one tells the patient why the doctor might want to this, and the first one doesn't.

And patients aren't as passive as they used to be.

"It does seem as if a few people have, ahem, kind of missed the point of Northrup's ironic rant."

If his point is that the blogosphere is hardly an original source of scientific enlightenment, then I fail to see that what he has to say is of any real value. Bloggers may not be doughty researchers on the cutting edge of scientific enquiry, but they do on occasion serve as useful disseminators of information that may be old hat to the scientifically informed, but is hardly well known by the public at large.

If one wishes to deny that the role blogs can play in dispelling pseudoscience and countering fear-mongers is of any real worth, one might as well cast aspersions on the efforts of popularizers like Stephen Jay Gould and Carl Sagan while one is at it. Otherwise, it serves no useful purpose to make statements like Andrew Northrup's, unless one's true intention is to sneer self-indulgently at all those other bloggers who have ideas above their station. Far many more people are likely to read a comment by someone like Glenn Reynolds than will ever stumble upon the "Proceedings of the National Academy of Sciences."

Bloggers may not be doughty researchers on the cutting edge of scientific enquiry, but they do on occasion serve as useful disseminators of information that may be old hat to the scientifically informed, but is hardly well known by the public at large.

It's not forbidden by the laws of physics, but it's not the usual model. The usual model is complicated scientific questions being treated like newspaper editorials, where people try to develop first principles arguments about why such-and-such a scenario is absolutely impossible or self-evidently true, and then attack their opponents' character. Exhibit A.

(That said, the straight news media doesn't do a particularly good job either.)

Far many more people are likely to read a comment by someone like Glenn Reynolds than will ever stumble upon the "Proceedings of the National Academy of Sciences."

Yeah, exactly. And if Glenn Reynolds hasn't stumbled on the proceeding either - which I'd bet a tidy sum he hasn't - how is this preferrable to reading the entrails of sheep or receiving the truth from an ecstactic vision? And if we're going to pay no attention to people who spend their lives working on these problems, isn't it just common courtesy to tell them, so they can go home and play Xbox?

Abiola Lapite writes:

"If [Northrup's] point is that the blogosphere is hardly an original source of scientific enlightenment, then I fail to see that what he has to say is of any real value."

I'm perfectly aware that bloggers sometimes "serve as useful disseminators of information." It's also true that the blogosphere is rife with the kind of overheated we're-so-great rhetoric that Northrup was making fun of. I've committed some of it myself.

The "real value" of Northrup's remarks was that they made me laugh. Your mileage is fully entitled to vary, but I really see why you're getting so worked up over it.

Before you launch another riposte, ask yourself: how likely is it that I don't actually value the ability of intelligent bloggers to dig up relevant left-field information, "fact-check asses", dispel folly, and so forth? ObSheesh: Sheesh.

Jordin says, "OK, its most likely effect -- cancer -- is widely dreaded."

I've always joked that if I get cancer [1] it will be in my right elbow. I've broken that elbow four separate times and thus have had a lot of x-rays in that part of my body.

[1] Given my family history, it's more like "when"; both my parents died of cancer. Neither of which was in their elbows.

I would add a modern assumption that any scientific advance will be either vital or lethal. I don't know if this assumption is based on headline stories' exaggerated views, or on some inheritance from Aristotelian drama.

In my opinion, Aristotle's exclusion of the middle has done more damage to the development of human epistemology than any method of brain programming before or since (not to mention that it made possible many of the subsequent ones, and many shrill dualistic ideologies along the lines of Objectivism).

It's certainly true that scientists know more about the chemistry/physics/biology/etc. of various health risks than the general public. However, I don't think that it follows that we should believe the report from a scientific organization about some risk is the last word on the subject. Science is very good at foundational questions, such as what is the molecular structure of hemoglobin, and what is the nature of gravity. It really isn't tremendously successful in answering many practical questions such as whether substance X causes cancer. Those questions do eventually get answered, and they get answered by scientists. However, before the final answer comes, there can be many tentative answers, and those tentative answers can contradict one another. Worse, we often can only distinguish final answers from tentative answers in hindsight.