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This year is the 20th anniversary of the NATO bombing of Yugoslavia/Serbia. At the moment, Serbian media outlets are focused on claims that depleted uranium in NATO bombs used during the bombardment might be causing an increase in the number of cancer cases in the country.

For example, The Serbian Monitor:

We already have solid evidence that in Serbia, and especially the south part of the country, due has seen an increased number of cancer patients and cancer-related deaths due to the use of depleted uranium ammunition, and that the environment is heavily polluted.

From a cursory search online, it seems that good, reliable evidence either supporting or rebuking these claims is hard to come by.

Is there quality, reliable evidence that Serbians are suffering from cancer due to depleted uranium in ammunition used during the bombing?

kozina-adjacent
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    Have you read [Wikipedia on depleted uranium / health considerations](https://en.wikipedia.org/wiki/Depleted_uranium#Health_considerations), and what wasn't answered by that article? – DevSolar Jun 24 '19 at 12:41
  • There are many citations linked to the Wikipedia article. The problem is that the vast majority are retrospective analyses, which still leaves open the question of causality and the many other possible causes leading to cancer in those particular populations. Another point is that many of these studies are from the 90s and early 00s and it would be nice to see something more up-to-date. Finally, there's no way for a novice like myself in this area to critically evaluate each of these articles in a timely fashion. If someone could point me in the right direct, it'd help out. – kozina-adjacent Jun 24 '19 at 14:07
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    You have edited asking for "reliable" evidence. This is assumed, and enforced, for all questions. Opinions are not on topic here, and all significant claims must be referenced. So, all the edit is doing is making it harder for people to skim and decide if they want to read the question further. – Oddthinking Jun 24 '19 at 15:51
  • One thing some of the answers could address is just how much dust there is likely to be, how that dust behaves over time (floats in the air forever, settles within minutes?) and the kind of rate at which crops and drinking water sources take up heavy metals. There's no doubt standing in a room full of DU dust is bad. But living near a field where a battle took place weeks (months, years...) ago...? – Grimm The Opiner Jun 25 '19 at 15:35
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    Hang on a second. DU is used by tanks to kill other tanks. Why would it be in bombs? – Gaius Jun 27 '19 at 09:55
  • @Gaius You're correct - it's not necessarily in _bombs_ but during _the bombing_. According to a [2001 WHO report](https://apps.who.int/iris/bitstream/handle/10665/66930/WHO_SDE_PHE_01.1.pdf?sequence=1&isAllowed=y), NATO fired roughly 10 tons of 30 mm armor-piercing DU munitions in Kosovo and about 2 tons of 30 mm DU munitions in Bosnia and Herzegovina during the wars in the former Yugoslav republics. So mainly from ground-attack aircraft it seems. – kozina-adjacent Jun 28 '19 at 10:46

2 Answers2

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There are several points to consider here.

1) Depleted Uranium is not that much "depleted".

"Depleted uranium," the byproduct of the enrichment process, has about 0.002 percent 234U, 0.2 percent 235U and 99.8 percent 238U, and about 60 percent of natural uranium's radioactivity.

-- U.S. Office of the Secretary of Defense, emphasis mine.

2) Uranium is pyrophoric -- munitions that hit a hard target will ignite.

Upon impact on a hard surface, a uranium penetrator will undergo planar fracturing, i.e. it will "self-sharpen". (This is one of the characteristics that make uranium a viable choice for armor-piercing munitions.) It also means that what comes out the other side of the armor plate is no longer a solid penetrator, but a cloud of uranium, which will then ignite as uranium is pyrophoric.

This also means that what is being left on a battlefield is not the same thing as is lying around in a US arsenal (a metallic DU penetrator), but mostly triuranium octaoxide (U3O8), plus uranium dioxide (UO2) and uranium trioxide (UO3).

-- Report of the World Health Organization Depleted Uranium Mission to Kosovo, page 6.

Which will then get into the dust you breathe, the water you drink, and the food you eat, much more readily than a couple pounds of solid DU...

3) Uranium is toxic.

Uranium is a heavy metal, in itself already quite toxic. Many of its compounds are even more so. Think "mercury" and you are not far off the mark.

4) Uranium is mostly an alpha emitter.

That's fine if you are handling uranium (that lump of metallic DU), because alpha particles don't even penetrate your outer skin, let alone gloves.

But if you get an alpha emitter inside your body (like inhaling dust, or eating contaminated food), that's actually worse than e.g. a gamma emitter, because alpha particles do much more damage to what they do hit. What might be negligible on your outer skin does become a problem in your lung tissue, or your kidneys, where radiation does not have to penetrate deep to cause damage.

And since it's next to impossible to decontaminate the insides of your lungs, or your blood stream, those alpha emissions won't stop anytime soon.

I'm looking for hard evidence from well thought out scientific studies - not hearsay, not anecdotal, not sensationalism.

British Army doctors do think so, for one...

The big problem with all of the above, as with any chemical / radiological contamination, is to prove causality. People do get cancer. Children are born with birth defects. Sometimes numbers go up, sometimes they do get down. How can you prove that they went up for one specific reason, to the exclusion of anything else?

You don't do "in vitro" studies where you feed people uranium compounds, or let them breathe dust with uranium compounds in them, to compare their health compared to a control group...

Plus, especially following a large-scale conflict, getting reliable data on e.g. cancer rates before a conflict vs. after a conflict can be hard. The WHO report I linked above, for example, came up "inconclusive" in no small part due to the difficulties in getting reliable statistical data.

We know that uranium compounds are unhealthy, both chemically and radiologically. Not just resulting in cancer, but other unfavorable conditions as well.

In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU.

-- Hindin, R.; et al. (2005). "Teratogenicity of depleted uranium aerosols: A review from an epidemiological perspective"

So, dodging the question as-asked because I know there are people out there just waiting to pounce on this because I cannot come up with a conclusive study for cancer in Serbia specifically... if in doubt, stay away from places where DU munitions hit hard objects. It's definitely not beneficial for your health.

DevSolar
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    First, thanks for taking the time to respond so thoroughly - you're way more knowledgable on this than I am. And yes, there's no reasonable IRB in the world (I hope) that would approve a trial in which a human experimental group receives a dose of uranium. That being said, there might certainly animal studies out there. You hit the nail on the head - the problem is finding non-retrospective data on this. "Uranium is toxic" is what is pushed by the media here and, while true, it isn't nuanced enough. So yeah... it's tough to know what's going on. – kozina-adjacent Jun 24 '19 at 14:04
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    @user93377: Animal tests are mostly how we know that uranium *is* toxic (if you follow the link "quite toxic" you will see what I mean). But as with all these things, as there isn't a hard number "below this you're safe", and no hard number "above this and you'll get cancer", there will always be those doubting that A is the cause for any specific case of B. There's people who claim that the only people that died as result of the Chernobyl accident were the ~30 that died of *acute* radiation poisoning, as you can't *prove* the other cases. Uranium **is** unhealthy. – DevSolar Jun 24 '19 at 14:10
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    Perhaps also include that "inconclusive" is also result of military boycott to release exact data on roubnds fired and target sites. DU is wilfully ignorant pollution and contamination. By saying we only "bombed here" (in fact also there) cancer elsewhere is calculated into background falsely. Eg 10.1016/j.jenvrad.2017.03.013 / doi:10.1016/j.microc.2004.10.014 / 10.1080/10937400490452714 / 10.1002/jat.841 / 10.1080/13623690008409524 – LangLаngС Jun 24 '19 at 15:18
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    @LangLangC: To be fair, *any* warfare is willful pollution and contamination. Fuel, oil, unsavory chemicals by the kilotons, wreckage... – DevSolar Jun 24 '19 at 15:23
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    And there's also the fact that war will expose the people to all sorts of other harmful materials. Pointing a finger at one specific cause it effectively impossible. – Loren Pechtel Jun 25 '19 at 02:36
  • @DevSolar In order to make this conclusion, you also have to show uranium quantities around Serbia. You can't just assume that there's a lot of it. – wizzwizz4 Jun 25 '19 at 11:33
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    @wizzwizz4: No I don't have to show that. That DU munitions *have* been used is uncontroversal. I have shown that DU munitions hitting their intended target *increases* the bioavailability of said uranium. I have also shown that uranium and its compunds are a health risk both by their toxicity and their radiological properties. If you want to make the statement that "DU munitions do *not* cause cancer / health problems" (despite being put into the environment, which again is uncontroversial), I put the burden of evidence plainly on your shoulders. – DevSolar Jun 25 '19 at 11:55
  • @DevSolar All of those things are true. It is reasonable to assume, from your first statement, that there are reasonably high levels of depleted uranium oxides hanging around Serbia. However, you haven't provided evidence for this, so it's nothing more than an assumption. – wizzwizz4 Jun 25 '19 at 12:00
  • I'm not claiming that DU munitions are safe. But, this _is_ [Skeptics.se]. Guesses and reasonable assumptions aren't good enough. – wizzwizz4 Jun 25 '19 at 12:00
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    @wizzwizz4: Who, exactly, is skeptic of the *presence* of DU uranium? NATO said "yes, we used it". Serbia says "yes, they used it". The WHO says "yes, they used it." Nobody (except perhaps you) is saying "it isn't there". – DevSolar Jun 25 '19 at 12:02
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    @DevSolar "and that the environment is heavily polluted" is part of the claim, and part that you've assumed, but haven't addressed. I have never, in my life, seen evidence that the environment in Serbia is heavily polluted; I'd probably bet on it, but that's not good enough. – wizzwizz4 Jun 25 '19 at 12:08
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    @wizzwizz4: Part of the claim is also "an increased number of cancer patients and cancer-related deaths", so even a *small* increase would verify the claim in that regard. There's a way of being skeptic about something, and being apologetic / in denial about something. Perhaps you might want to refer to the second comment. I've got nothing to add. – DevSolar Jun 25 '19 at 12:11
  • "And since it's next to impossible to decontaminate the insides of your lungs, or your blood stream, those alpha emissions won't stop anytime soon." I've seen a couple of statements like this recently here and I'm not a doctor, but I'm pretty sure our lungs have mechanisms that allow them to clear dust. Yes, certain materials such as types of asbestos can get trapped but it's not like we carry around every mote of dust or smoke that we've ever breathed. Do you have some reference that talks about this kind of dust and whether the lungs can clear it? – JimmyJames Jun 25 '19 at 15:02
  • The "British Army doctors" article states "Inhalation of insoluble uranium dioxide dust will lead to accumulation in the lungs with very slow clearance - if any" but doesn't elaborate with sources or any explanation of why. – JimmyJames Jun 25 '19 at 15:05
  • None of this is what I'm used to calling reliable evidence. Quite a bit of reasoning that somebody could try to find ways to poke holes in. Unless they're measuring uranium exposure it could all be dismissed as not a significant source. – Joshua Jun 25 '19 at 18:14
  • @Joshua: And if they've measured uranium exposure on one battlefield you'll complain about another being different. And once they've measured them all you'll complain that there is no proof that any of that actually led to cancer, and that there might be other factors. And once... sorry, at some point you'll have to accept that "this is as good as we know at this point". Which doesn't falsify the claim. All I'm saying here is "possibly, perhaps probably", and that *is* as good as we know ATM. – DevSolar Jun 25 '19 at 18:19
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    @DevSolar: No actually I won't. I know how to do random samples. – Joshua Jun 25 '19 at 18:22
  • @Joshua: What, exactly, is your suggestion about improving this answer? Because I can do without the one-liner trolling. The ones who could *easily* do samples of DU exposure -- the militaries involved -- don't. – DevSolar Jun 25 '19 at 18:25
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    If you mention that *"Depleted Uranium is not that much depleted."* we should also mention that uranium, even non-depleted uranium, is **not that much radioactive at all** if it's not enriched. It is toxic because it's a heavy metal, but so is lead and many other non-radioactive heavy metals. Depleted uranium is used in armor-piercing munitions because of its density. Another metal with similar properties is tungsten, which is not radioactive, but is also toxic just like any other heavy metal. Why use uranium instead of tungsten? Simply because it's cheaper. – vsz Jun 25 '19 at 20:27
  • @vsz: I consciously did not go into whether this or that effect is this or that much of a threat, because there simply aren't hard numbers available. I also don't think that the OP needs a description of *why* DU is used in AP munitions. And about the radioactivity, even pure U235 is more radioactive than U238 only by a factor of ~6.5 Ci/g. Granted, a significant amount of that is gamma radiation instead of alpha, but as I pointed out, once you got the radiation source *inside* your body, alpha is actually worse... – DevSolar Jun 25 '19 at 20:47
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    It seems to me like the critical missing link here is what the actual levels of (depleted) uranium are in the ground/water/food of Serbia, compared to say, other places in Europe where DU rounds weren't used. – mbrig Jun 25 '19 at 21:31
  • @DevSolar playing devil's advocate here: given the time since the use of DU rounds (which btw are not radioactive above background levels, but that aside) it's quite feasible that any Uranium that entered the environment as a result of that use has since been washed away and/or otherwise diluted to the point where it's impossible to distinguish from background levels due to natural causes. I don't have data to show either whether this is the case or not, but it's not inconceivable. – jwenting Jun 26 '19 at 04:01
  • @vsz not just cheaper, but also heavier and less brittle and therefore superior when it comes to its armour piercing properties. The main reason to use tungsten is availability rather than any other factor (DU being rather hard to get for countries without a large nuclear industry). – jwenting Jun 26 '19 at 04:02
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    @jwenting : my point was that people focus on depleted uranium because it *sounds scary*, because it implies something "nuclear", and then people can vilify their users by claiming or at least implying that they were deliberately irradiating civilians. I wouldn't even have bothered commenting, if not for the argument in the answer that it's "not that much depleted". If *that* is mentioned, then it's only fair to also mention that it's not that much radioactive either. Yes, it's toxic, but so is lead, which has been used in munitions since many centuries. – vsz Jun 26 '19 at 04:18
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    @vsz ikr. DU is just another hunk of really heavy material, nothing that special about it. And given the plethora of rather toxic and often carcinogenic materials that get released when an armoured vehicle burns to a crisp, the small amount of Uranium oxides released isn't going to add much of a problem. – jwenting Jun 26 '19 at 04:22
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Check out this paper: Cancer mortality in Serbia, 1991–2015, published in 2018. The study is based on official data on cancer-related deaths. The conclusions drawn by the authors are:

  • Overall cancer mortality rate (ASR - age-standartized rate) increased between 1991 and 2009 by 0.8-0.9% per year.
  • After 2009, the trend changed to decline, again by 0.9% per year.

enter image description here

However, the authors don't link this trend to the effects of DU. Rather they mention contamination in general, along with the decline of living standards and the degradation of health services after the conflict which are also expected to contribute to cancer mortality.

All in all, Serbia is among the countries with the highest cancer mortality rates, but those rates were already significantly higher than the average before the conflict. Among the causes, the authors mention smoking, obesity and the use of hormonal contraceptives. Another rather peculiar factor is the radiation treatment against head lice (which was done in 1950–1959), although there's no clear evidence that the treatment itself was the cause, as opposed to poor living conditions after the WWII.

Dmitry Grigoryev
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  • This doesn't answer the question. –  Jun 25 '19 at 16:13
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    @BenCrowell it does provide an answer in that it shows clearly that experts don't consider DU to be the (main) cause of the increase in cancer cases in Serbia during and after the civil war. Without evidence that they're wrong (which you fail to provide) I see no reason to doubt that statement (in part at least because of my knowledge about the physical properties of Uranium and similar substances). – jwenting Jun 26 '19 at 04:05