Chemically what's going on is that deuterium substitution causes the vibrational energy states of molecules to change, because it's heavier. This messes with things like hydrogen bonding and also causes the kinetic isotope effect (reactions with deuterium happen more slowly).
I'm highly skeptical of the claims that depleting deuterium in water can cure cancer. The amount naturally present just isn't very high to start with, and I don't think it's likely to have cancer-promoting effects.
Also:
>every time he drinks water, Castro calls in a chemist to test it for any impurity first; the tests can detect any contaminant to within a trillionth of a gram.
Presumably the chemists would notice the increased density?
"The Hunza people of Pakistan drink mostly glacial meltwater. Because its freezing-and-melting cycle replicated Castro's freezer in reverse, their water is naturally lighter than usual."
Wait, I'm confused how these processes are opposites, as I'm reading this they seem like the same process? What am I missing?
Greg Cochran had a similar idea in 2015: "So, you can poison someone with heavy water – but although the authorities probably wouldn’t detect it, it takes a lot, and it’s expensive. Stick to thallium. However, just because small amounts of of deuterium are nonlethal, doesn’t mean that they’re harmless. They might be: or they might not. Nobody knows, because nobody has ever looked. You could think of deuterium as a source of noise in biological systems – and maybe those systems would work better without that noise." https://westhunt.wordpress.com/2015/02/05/dont-drink-the-water/
_Kampen om tungtvannet_ (The Heavy Water War) is a very good six-part historical drama about Norsk Hydro's heavy water plant at Rjukan, a key strategic asset during WWII because of heavy water's importance to Nazi atomic weapons research, and the Allies' attempts to sabotage the factory. The Germans intended to use the deuterium-rich water as the main neutron absorbing agent. Thankfully this turned out to be the wrong choice. Anna Friel and Christoph Bach, who plays Heisenberg, gave especially good performances.
Isn't the effect of removing a very tiny fraction of Deuterium going to basically be nothing? Like if water is normally 1/3200 deuterium, even removing 100% of the deuterium is a very small absolute increase. Whereas heavy water is 3200 times different. Further, we already know based on the heavy water stuff that swapping to regular hydrogen for deuterium is not that impactful except at incredibly high amounts, so one would not expect there to be any noticeable or meaningful change from light water.
Someone should do a long term evolution experiment in D2O. (E. coli grow at reduced rates in D2O, but are otherwise fine). Ideally you could do this in some kind of minimal media and have all hydrogen sources be deuterium (though maybe that would cost too much to be worthwhile).
Also, using NASA BYOES kits made of "plastic" (batch controlled? probably not) and which included "normal water" and "marine salts" is ... uncontrolled, and the "office desk" environment and shuffling method are not described. Nor is the lighting controlled in the methodology.
There might be something worth investigating, is the best that can be said.
Weird “Lattice of Coincidence” moment just now. I had turned the page of a book to a chapter heading “The Unbearably Heaviness of Remembering” when I check my email and saw the ACX update.
Minor pedantic point: you wouldn't be making "semiheavy water" specifically; you're just increasing the fraction of deuterium in the water generally, since the water molecules (in a liquid) are constantly exchanging hydrogen ions. If you keep the deuterium enrichment process going long enough, you'll end up with mostly D2O.
I think that the exact proportion of water that a human body is made of is somewhat controversial: some quick searches turned up many different figures between 47% and 80%. IIRC there once was someone who searched up the phrase "Your body is X% water" for every value of X, but I can't seem to find records about that now.
I realize just am nitpicking a single detail, but...
"because heat preferentially increases the evaporation of heavier water" Don't you mean preferentially increases evaporation of _lighter_ water?" that is, lighter water evaporates more, and what heavy water does evaporate will be quicker to precipitate?
Somlyai is also [principal scientist](https://www.ddcenters.com/dr-somlyai/) at the Center for Deuterium Depletion, which is selling deuterium testing kits and "Metabolic Wellness" courses; and he is running an [annual conference on deuterium depletion](https://deuteriumdepletion.com/). So yeah, it does seem a bit sketchy - the people behind this line of research seem much more interested in commercial activities than in producing solid proof.
My first thought was "If I had a time gizmo giving me a thousand years to dink around, I suspect I could find something more valuable to do with it than killing Castro."
I actually figured there was maybe a ~20% chance that this was exactly the point you were planning to make. "Noticing when the resources you have been offered permit a greater accomplishment than the one you were originally aiming for" seems like the sort of rationalist skill that you might write a blog post to promote. (Even if it tends to annoy the authors of lateral-thinking puzzles.)
What happens if you run this process in reverse and drink nothing but heavy water? In the tabletop game High Frontier, the Heavy Water Survivalists are a bunch of "Libertarians, doomsayers, gun-nuts, and others" who "are convinced that the Earth is kaput.". Since they're fleeing to space, "Survivalists drink only Heavy Water (D2O) to improve their resistance to radiation." - but (a) would this actually work, and (b) would it negatively affect their health, given the effects of heavy water discussed here?
what about the C and N and O isotopes? Those probably have less effect, due to the difference in atomic weight being much less as a percentage, but maybe some. Many of these isotopes are also naturally fractionated, “ Some plants,
such as rice and wheat, are depleted in C-13, and you can enrich water in D2O by running it through barley mash” Rarer (sometimes radioactive, or in the case of measuring water turnover deuterium) isotopes of common elements are extremely useful for measuring the movement of chemicals or the movement of those elements through reactions with chemicals in biology. https://en.m.wikipedia.org/wiki/Isotope_analysis (Also goes into a lot of natural isotope fractionation).
Wait a minute, wouldn't this make the perfect murder mystery-thriller novel combo? An untraceable poison, so expensive that it must have taken a conspiracy of the most wealthy and powerful people in the world, and so technical that the average reader wouldn't be able to see the twists and turns coming... with a bit of work, I think this could be a Hollywood worthy script.
You could probably only sell it to the sort of people who make movies like '2012' or 'The Core', who are looking for the thinnest veneer of 'Science!' to justify regular old movie plotlines, though... if you want to have more negotiating power to insist on a more braintwisting movie though, one that focuses on the murder mystery as much as the thriller, you'd most likely have to publish the idea as a novel first and hope it takes off. Then if it does, hope Hollywood approaches you asking for a movie adaptation. If all goes well, you might have another 'The Andromeda Strain'-level techno-thriller on your hands.
(Though if it doesn't, you'll be nothing but just another failed genre writer... then again, if you don't invest too much into this, that won't be such a bad fate.)
I'm not a doctor or even a scientist, but I was diagnosed with metastatic prostate cancer last year and have read a lot of papers on the subject since then. Most studies that actual current treatments are based aren't all that great in my opinion, but the "Deuterium Depletion May Delay the Progression of Prostate Cancer" paper is *much* worse than that. For the prospective part: N=44, P~=0.05 and a relatively big difference in initial PSA (406.4 vs 521) between the treatment and control groups. Retrospective studies are always dubious and this one is also very small.
I, personally, would not want to kill Castro, as he brought many social advancements to Cuba and assassinations are historically a terrible way of changing a country for the better. Now if the riddle was about assassinating someone i didn't like, i would painstakingly freeze and refreeze that water.
I was thinking I'd poison Castro by using electrolysis to separate hydrogen from oxygen, then ignite the water in his presence. He just has to die, right?
"And every time he drinks water, Castro calls in a chemist to test it for any impurity first; the tests can detect any contaminant to within a trillionth of a gram. "
According to homeopathy such dilution is still orders of magnitude greater than what's required to poison him!
My impression is that you need at least 20% D2O for promptly noticeable effects in mammals, and IIRC lower beasts like protzoans and such can adapt to survive just fine at 100%. So I'm pretty comfortable with the prior that reducing the amount of HDO and D2O in normal water from 1 part in 3000 or 6000, respectively, to 1 part in a million or so will do absolute bupkis.
Or more precisely, whatever effect it *might* have will be utterly drowned out by whether your neighbor is smoking again with his living room window open, or you sat behind a diesel truck at a stoplight this morning, or happened to be standing below a cosmic ray shower in your backyard this afternoon, or you caught an extra whiff of radon when you walked by a fresh posthole on your way to get an ice cream, or there were a few thousand Aspergillus flavus on the peants you had with your martini.
I happen to have thought about this in the past, but mostly for plants. My background is experimental physics, and I was working at a neutron scattering facility, where we used neutrons diffraction to measure the crystal structure of things. I'd heard claims about bananas frozen at liquid nitrogen temperatures having a different crystal structure to bananas frozen at standard freezer temperatures. So naturally, I wanted to test it, using neutron diffraction.
The thing is, it's a lot harder to use neutron scattering to measure the crystal structure of normal ice than it is with heavy ice. So we wanted to deuterate a banana. But I wasn't sure how to do that. I figured a banana tree would probably die if I tried to grow it using heavy water. But then someone suggested that we just give it heavy water while it's growing bananas. I still think this would be likely to kill it?
Unfortunately, I moved on before we ever tried the experiment. I'd still like to know how to deuterate a banana, though.
There's a small flaw in the insidious poisoning plan: it turns out that heavy water tastes different, namely, noticeably sweet, which would probably raise some suspicion somewhere along the way. The chemist/ skeptic Phil Mason (known on Youtube as Thunderf00t) got a fascinating video ("Why does Heavy Water taste sweet?") on that discovery (that he was involved in).
The "a review paper here" link (oncological argument) took me to a page that downloaded a paper entitled "How E-Business Platform Channels Influence Chinese
My favourite thing about this freezing discrepancy is how it comes about - I learned it mid-undergrad, and while I've forgotten some of the exact workings, still find it absolutely delightful:
The vibrational states that a molecule like water can attain are determined by the symmetries of the molecule - we spent a lot of time on some pseudo-group theory until we could work out from the shape of a (small) molecule which vibrational states it can attain. Here's where I can no longer do the precise working, but the symmetries of H20 and D20 are such that they each access a subset of the same set of energy levels, one of them can only access even-numbered levels, and the other one only odd-numbered levels!
Where does that get us different freezing temperatures? Well the gaps between energy levels diminish as you go up - so the gap from level 0 to 1 is larger than from 1 to 2 is larger than from 2 to 3 etc... That means the gap from 0 to 2 is just enough larger than the gap from 1 to 3 that it affects how much energy it takes to freeze the different molecules!! So really you'd be aiming to kill Castro with group theory.
When something's less toxic than table salt, I feel "pretty toxic" is an overstatement.
>The basis of cellular energy generation is the proton pump in the mitochondria, which moves hydrogen nuclei around to create a charge gradient. If the hydrogen nuclei have unexpected neutrons, that could jam the pump or change how the gradient works. I'm not entirely able to follow this, but maybe then there is some kind of cellular signaling cascade?
The basic problem with deuterating organisms is that the kinetics of acid-base reactions are significantly different with deuterium (and the thermodynamics are somewhat different - pH of neutral heavy water is 7.44 instead of 7.0 i.e. only 36% as much is dissociated) and screwing up the relative kinetics of things disrupts the functioning of highly-tuned systems like multicellular eukaryotes. Less complex organisms tend to have wider tolerances on these things (partially due to less things to go wrong, partially because the environment of single cells in a multicellular organism is subject to homeostasis and as such adaptability on the cell level isn't normally required), hence why you can grow 100%-deuterated bacteria.
If it came to my attention that Google was genuinely and openly asking about killing Castro in employee interviews, or about doing any other illegal American security state stuff, I'd grow highly concerned and endeavor to stop using Google products as much as a I can (well, in addition to my efforts to already do so, of course).
There are tons of biochemicals besides deuterium where deviating above or below the normal homeostatic levels can kill cells. So when high-D and depleted water both kill cancer cells, not too surprising and I wouldn't count one claim as evidence against the other.
Scott, the link of the supposed cancer review paper link [0] redirects me to [1]: "How E-Business Platform Channels Influence Chinese Auto-parts Wholesale Market?" A curious topic for a pharmaceutical journal, but who am I to judge?
Still, I find the claim of a 50% growth rate reduction in deuterium free water (as opposed to our normal almost deuterium free water) extraordinary. Not quite superluminous neutrino level extraordinary, but still surprising enough that one should get the late James Randi [2] involved or something.
I am not a physician, but from my understanding, cancer cells are not undead Chaos cells thriving on poisons, but basically normal human cells with an unfortunate mutation, running in a nonstandard mode. Generally, I would assume that the environmental requirements for cancer growth are a smallish subset of the environmental requirements of a healthy human. There are certainly things which harm cancer cells disproportionally (e.g. chemo therapy, radiation), but these things also tend to harm healthy tissue to a lesser degree?
This was pretty much exactly the plot of the final episode of the UK series Eleventh Hour starring Patrick Stewart, where scientists were testing water from a spring to see if they could find any contaminants that would explain why local people were being sickened, but all their tests came back negative till he thought to check the density of the water and found it was a secret government heavy water source. https://en.wikipedia.org/wiki/Eleventh_Hour_(British_TV_series)
Has anybody read The Unbearable Lightness of Being? It's pretty good. It's sort of a test kitchen for how different people can answer the questions of existentialism in different ways, and how it feels to live in each different answer. I should reread it sometime.
For whatever it says about me, my answer was to contaminate his water with small amounts of my poop. I don't have cholera or anything, but that has to be at least a little deleterious to health, right? Poop water? ...Google would not hire me with this answer, I think.
Scott, in your psychiatric practice have you encountered the use of Austedo (deutetetrabenazine)? A deuterated form of tetrabenazine, it is approved since 2017 for use in tardive dyskinesia and Huntington's disease.
There are also deuterated forms of paroxetine, venlafaxine, dextromethorphan, vitamin A, and other drugs, that have been of interest. The latter two are in phase 3.
The advantage of deuterated drugs is an alteration of pharmacokinetics, causing either prolonged or shortened duration of action or reduction of toxic metabolites. These effects are in some cases related to deuterium changing the interaction of the compounds with the active sites of various cytochrome subtypes, especially 2D6 and 3A4.
I'm surprised nobody's raised this nitpick yet, but -- surely you need to start with an amount of water that's much larger than "several thousand times Castro's daily consumption"? (Unless your values of "several" are extremely large, of course.) It seems like you need to end up with at least 100x Castro's daily consumption, and you're halving your amount of water at every freeze/melt iteration.
IIRC the reason ²H is toxic is because proton pumps are evolved to pump ¹H. ²H has twice the mass, so by F = ma you need twice the force. But obviously proton pumps aren't evolved to push with twice the force.
Also, a fun bit of trivia is that D₂O is slightly sweet.
>You would never think to check whether attempts to mine the Martian icecaps for drinkable water will result in dangerous water that could sicken the unfortunate astronauts who drink it (answer: it might! Martian water has five times more deuterium than Earthly water and seems to kill shrimp)
And if there's anything I learned from Doctor Who, it's that drinking Martian water is a baaaaaad idea.
I read this as an elegant rejoinder to several different points of view regarding Ivermectin expressed in the comments section of the recent "Too Good to Check" post.
> Start with the evolutionary argument. [...] The 10,000 years since the last Ice Age wasn't enough time to re-evolve, so human bodies are probably adapted for slightly lighter water than we get.
What? That's not an evolutionary argument, it's an "I don't believe in evolution" argument.
"Light water halves the growth rate of cancer cells in vitro"
"but some other groups find deuterium causes less cancer, so who knows?"
That effect size seems too big... But anyway, let's take it at face value. With the in vitro part it wouldn't even be that surprising. If our cell chemistry is tuned to the current amount of deuterium in water (ie, pre-ice-age and also current levels), which seems a reasonable prior to me, then any direction of variation, up or down, would harm cancer-cell growth... as well as other-cell growth. The same story as all in-vitro/in-vivo cancer drug studies: Po-210 kills cancer cells real good, for that matter.
Again, half the rate, really? I haven't read the article, but I'd be more enticed to spend my time by a more reasonable claim.
OK but if you make ice cubes out of heavy water, they will sink in your normal-water-based drink, which is a great party trick and totally worth a small probability of dying of cancer or whatever
I have a better memory than most and I did remember deuterium. We can say perhaps it's not the first thought, but better it's there than not.
The takeaway is that we have to remember that people are not the same, and that we, each, ourselves, have to be careful and avoid assuming, and understand that we don't know everything.
This is much like Harvard and the seasons, which was evidence of an appalling lack of curiosity, memory, and grounding in the real world
I thought of a bunch of other ways to kill Castro, all variously contrived. Various ways to make water toxic. All rely on the sensor just checking for contamination and not other properties
- swap the water for deionized water (deionize it in the kitchen). I know there is concern about drinking deionized water because it can strip minerals and salt from your body. So maybe this will weaken and eventually kill Castro?
- concentrate or remove H groups in the water (somehow). I would imagine you could make an acid or a base this way. So he drinks it and dies horribly?
- 3rd and best option : heat the water in the watercooler to an extremely high temperature, perhaps 600F, but in such a way that it has no impurities or micro structures to form bubbles around so that it cannot boil- no nucleation sites!
Then when Castro is near and the sensor probe/cup/valve, etc opens, there is an introduced nucleation site, then the water can all instantly boil and explode in a massive steam bomb. Bonus points If you also made it a powerful acid so it’s a huge acid cloud doing 10d10 damage to Castro.
This last phenomenon happens sometimes when you microwave water in a really clean container, then drop a spoon in later and it explodes.
The riddle says "the tests can detect any contaminant at any concentration", so it seems like there's an implicit "except for differing isotopes of water", which overfits the riddle to this particular answer. This seems a little fishy, since semiheavy water would be really easy to detect!
Semiheavy water is about 5% denser than normal water, so even with a fairly imprecise scale, the swap could be detectable, and I have a hard time believing that any battery of tests wouldn't end up computing the density of Castro's water. If I'm the chemist, and I notice that the 100mL samples I'm pulling to check for cyanide or whatever are suddenly weighing 105g, I'm probably asking questions.
Knowledge is exhausting - I sometimes find myself vacillating between Errol Morris’ conviction that there is a real and verifiable “truth” and, on my worst days, a post-modern relativity. The replication crisis and the current Covid wars over every damn thing doesn’t help. I miss simpler times when Encyclopedias Brown and Brittanica provided clear answers.
Along similar lines, have you come across the hypothesis that different isotopes of lithium have different psychiatric properties, and the inference that this implies quantum effects are important in cognition? see e.g. https://www.kitp.ucsb.edu/sites/default/files/users/mpaf/Ettenberg%20et%20al%20Lithium%20Isotope%20v.2%20.pdf and https://www.news.ucsb.edu/2018/018840/are-we-quantum-computers. The person pushing this argument (Matthew Fisher) is as distinguished as they come, and it actually seems maybe crazy enough to be right (although I'm a physicist, not a neuroscientist or psychiatrist).
Chemically what's going on is that deuterium substitution causes the vibrational energy states of molecules to change, because it's heavier. This messes with things like hydrogen bonding and also causes the kinetic isotope effect (reactions with deuterium happen more slowly).
I'm highly skeptical of the claims that depleting deuterium in water can cure cancer. The amount naturally present just isn't very high to start with, and I don't think it's likely to have cancer-promoting effects.
Also:
>every time he drinks water, Castro calls in a chemist to test it for any impurity first; the tests can detect any contaminant to within a trillionth of a gram.
Presumably the chemists would notice the increased density?
If you have regular access to Castro's kitchen and kitchen appliances you don't need to poison him at all; just grab a knife and shank him!
Geez. The “we use cookies” disclaimer at the site selling light water displays in Hungarian in my browser. Seriously. Just this once I’m not joking
[Insert your own joke about the Scott’s high expectations of his readers here]
Google hasn't set riddles for over a decade. Now it's a standard coding interview.
"The Hunza people of Pakistan drink mostly glacial meltwater. Because its freezing-and-melting cycle replicated Castro's freezer in reverse, their water is naturally lighter than usual."
Wait, I'm confused how these processes are opposites, as I'm reading this they seem like the same process? What am I missing?
I'm surprised you didn't explore the implications of this on climate change. For a second I thought you were heading that direction.
Greg Cochran had a similar idea in 2015: "So, you can poison someone with heavy water – but although the authorities probably wouldn’t detect it, it takes a lot, and it’s expensive. Stick to thallium. However, just because small amounts of of deuterium are nonlethal, doesn’t mean that they’re harmless. They might be: or they might not. Nobody knows, because nobody has ever looked. You could think of deuterium as a source of noise in biological systems – and maybe those systems would work better without that noise." https://westhunt.wordpress.com/2015/02/05/dont-drink-the-water/
_Kampen om tungtvannet_ (The Heavy Water War) is a very good six-part historical drama about Norsk Hydro's heavy water plant at Rjukan, a key strategic asset during WWII because of heavy water's importance to Nazi atomic weapons research, and the Allies' attempts to sabotage the factory. The Germans intended to use the deuterium-rich water as the main neutron absorbing agent. Thankfully this turned out to be the wrong choice. Anna Friel and Christoph Bach, who plays Heisenberg, gave especially good performances.
https://en.wikipedia.org/wiki/The_Heavy_Water_War
Isn't the effect of removing a very tiny fraction of Deuterium going to basically be nothing? Like if water is normally 1/3200 deuterium, even removing 100% of the deuterium is a very small absolute increase. Whereas heavy water is 3200 times different. Further, we already know based on the heavy water stuff that swapping to regular hydrogen for deuterium is not that impactful except at incredibly high amounts, so one would not expect there to be any noticeable or meaningful change from light water.
Someone should do a long term evolution experiment in D2O. (E. coli grow at reduced rates in D2O, but are otherwise fine). Ideally you could do this in some kind of minimal media and have all hydrogen sources be deuterium (though maybe that would cost too much to be worthwhile).
Counterargument: Searching Amazon for "deuterium depleted water" turned up "Liquid Death Mountain Water" (https://amzn.to/3jUJSQv).
> seems to kill shrimp
N = 50.
Also, using NASA BYOES kits made of "plastic" (batch controlled? probably not) and which included "normal water" and "marine salts" is ... uncontrolled, and the "office desk" environment and shuffling method are not described. Nor is the lighting controlled in the methodology.
There might be something worth investigating, is the best that can be said.
Weird “Lattice of Coincidence” moment just now. I had turned the page of a book to a chapter heading “The Unbearably Heaviness of Remembering” when I check my email and saw the ACX update.
The Lattice of Coincidence moment in “Repo Man”
https://m.youtube.com/watch?v=4ToUAkEF_d4
If light water is a lot better, I think it might taste better. I wonder how it tastes.
> And there's the oncological argument (that's the St. Anselm thing, right?)
I see what you did there...
Minor pedantic point: you wouldn't be making "semiheavy water" specifically; you're just increasing the fraction of deuterium in the water generally, since the water molecules (in a liquid) are constantly exchanging hydrogen ions. If you keep the deuterium enrichment process going long enough, you'll end up with mostly D2O.
> It's just that your body is 70% water
I think that the exact proportion of water that a human body is made of is somewhat controversial: some quick searches turned up many different figures between 47% and 80%. IIRC there once was someone who searched up the phrase "Your body is X% water" for every value of X, but I can't seem to find records about that now.
Along those lines - this is pretty convincing.
https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-part-i-mysteries/
Basically a preponderance of the evidence points to some food additive that entered the food supply in the mid 70s triggered the obesity epidemic.
I realize just am nitpicking a single detail, but...
"because heat preferentially increases the evaporation of heavier water" Don't you mean preferentially increases evaporation of _lighter_ water?" that is, lighter water evaporates more, and what heavy water does evaporate will be quicker to precipitate?
The Hungarians are working for [HYD LLC](https://www.researchgate.net/institution/HYD-LLC-for-Cancer-Research-and-Drug-Development), a company [selling depleted water](https://multi-vitamin.hu/markak-szerint/hyd-rakkutato-es-gyogyszerfejleszto-kft-preventa-csokkentett-deuterium-c103447) (for $5/l or so; the Amazon reseller must be making a hefty profit). The lead scientist, Gábor Somlyai, is the founder of HYD LLC. The company has been fined by the Hungarian Competition Authority a couple times for advertising medical benefits without going through any medicine approval process ([article in Hungarian](https://index.hu/tudomany/egeszseg/2014/01/24/1400_forint_a_csodaszer_literje)) and making a rather nice profit.
Somlyai is also [principal scientist](https://www.ddcenters.com/dr-somlyai/) at the Center for Deuterium Depletion, which is selling deuterium testing kits and "Metabolic Wellness" courses; and he is running an [annual conference on deuterium depletion](https://deuteriumdepletion.com/). So yeah, it does seem a bit sketchy - the people behind this line of research seem much more interested in commercial activities than in producing solid proof.
My first thought was "If I had a time gizmo giving me a thousand years to dink around, I suspect I could find something more valuable to do with it than killing Castro."
I actually figured there was maybe a ~20% chance that this was exactly the point you were planning to make. "Noticing when the resources you have been offered permit a greater accomplishment than the one you were originally aiming for" seems like the sort of rationalist skill that you might write a blog post to promote. (Even if it tends to annoy the authors of lateral-thinking puzzles.)
What happens if you run this process in reverse and drink nothing but heavy water? In the tabletop game High Frontier, the Heavy Water Survivalists are a bunch of "Libertarians, doomsayers, gun-nuts, and others" who "are convinced that the Earth is kaput.". Since they're fleeing to space, "Survivalists drink only Heavy Water (D2O) to improve their resistance to radiation." - but (a) would this actually work, and (b) would it negatively affect their health, given the effects of heavy water discussed here?
what about the C and N and O isotopes? Those probably have less effect, due to the difference in atomic weight being much less as a percentage, but maybe some. Many of these isotopes are also naturally fractionated, “ Some plants,
such as rice and wheat, are depleted in C-13, and you can enrich water in D2O by running it through barley mash” Rarer (sometimes radioactive, or in the case of measuring water turnover deuterium) isotopes of common elements are extremely useful for measuring the movement of chemicals or the movement of those elements through reactions with chemicals in biology. https://en.m.wikipedia.org/wiki/Isotope_analysis (Also goes into a lot of natural isotope fractionation).
Nature casual article about testing heavy water in animals and humans - https://sci-hub.se/downloads/2019-03-22/76/10.1038@s41557-019-0242-9.pdf also mentions that “some have suggested” heavy water might extend lifespan, and slow metabolism
Wait a minute, wouldn't this make the perfect murder mystery-thriller novel combo? An untraceable poison, so expensive that it must have taken a conspiracy of the most wealthy and powerful people in the world, and so technical that the average reader wouldn't be able to see the twists and turns coming... with a bit of work, I think this could be a Hollywood worthy script.
You could probably only sell it to the sort of people who make movies like '2012' or 'The Core', who are looking for the thinnest veneer of 'Science!' to justify regular old movie plotlines, though... if you want to have more negotiating power to insist on a more braintwisting movie though, one that focuses on the murder mystery as much as the thriller, you'd most likely have to publish the idea as a novel first and hope it takes off. Then if it does, hope Hollywood approaches you asking for a movie adaptation. If all goes well, you might have another 'The Andromeda Strain'-level techno-thriller on your hands.
(Though if it doesn't, you'll be nothing but just another failed genre writer... then again, if you don't invest too much into this, that won't be such a bad fate.)
I'm not a doctor or even a scientist, but I was diagnosed with metastatic prostate cancer last year and have read a lot of papers on the subject since then. Most studies that actual current treatments are based aren't all that great in my opinion, but the "Deuterium Depletion May Delay the Progression of Prostate Cancer" paper is *much* worse than that. For the prospective part: N=44, P~=0.05 and a relatively big difference in initial PSA (406.4 vs 521) between the treatment and control groups. Retrospective studies are always dubious and this one is also very small.
I, personally, would not want to kill Castro, as he brought many social advancements to Cuba and assassinations are historically a terrible way of changing a country for the better. Now if the riddle was about assassinating someone i didn't like, i would painstakingly freeze and refreeze that water.
Or just just use a double mechanism serving teapot with only one chamber full of poison. https://www.youtube.com/watch?v=kkrgUT70Mbo
I was thinking I'd poison Castro by using electrolysis to separate hydrogen from oxygen, then ignite the water in his presence. He just has to die, right?
"And every time he drinks water, Castro calls in a chemist to test it for any impurity first; the tests can detect any contaminant to within a trillionth of a gram. "
According to homeopathy such dilution is still orders of magnitude greater than what's required to poison him!
My impression is that you need at least 20% D2O for promptly noticeable effects in mammals, and IIRC lower beasts like protzoans and such can adapt to survive just fine at 100%. So I'm pretty comfortable with the prior that reducing the amount of HDO and D2O in normal water from 1 part in 3000 or 6000, respectively, to 1 part in a million or so will do absolute bupkis.
Or more precisely, whatever effect it *might* have will be utterly drowned out by whether your neighbor is smoking again with his living room window open, or you sat behind a diesel truck at a stoplight this morning, or happened to be standing below a cosmic ray shower in your backyard this afternoon, or you caught an extra whiff of radon when you walked by a fresh posthole on your way to get an ice cream, or there were a few thousand Aspergillus flavus on the peants you had with your martini.
I happen to have thought about this in the past, but mostly for plants. My background is experimental physics, and I was working at a neutron scattering facility, where we used neutrons diffraction to measure the crystal structure of things. I'd heard claims about bananas frozen at liquid nitrogen temperatures having a different crystal structure to bananas frozen at standard freezer temperatures. So naturally, I wanted to test it, using neutron diffraction.
The thing is, it's a lot harder to use neutron scattering to measure the crystal structure of normal ice than it is with heavy ice. So we wanted to deuterate a banana. But I wasn't sure how to do that. I figured a banana tree would probably die if I tried to grow it using heavy water. But then someone suggested that we just give it heavy water while it's growing bananas. I still think this would be likely to kill it?
Unfortunately, I moved on before we ever tried the experiment. I'd still like to know how to deuterate a banana, though.
There's a small flaw in the insidious poisoning plan: it turns out that heavy water tastes different, namely, noticeably sweet, which would probably raise some suspicion somewhere along the way. The chemist/ skeptic Phil Mason (known on Youtube as Thunderf00t) got a fascinating video ("Why does Heavy Water taste sweet?") on that discovery (that he was involved in).
The "a review paper here" link (oncological argument) took me to a page that downloaded a paper entitled "How E-Business Platform Channels Influence Chinese
Auto-parts Wholesale Market?"
My favourite thing about this freezing discrepancy is how it comes about - I learned it mid-undergrad, and while I've forgotten some of the exact workings, still find it absolutely delightful:
The vibrational states that a molecule like water can attain are determined by the symmetries of the molecule - we spent a lot of time on some pseudo-group theory until we could work out from the shape of a (small) molecule which vibrational states it can attain. Here's where I can no longer do the precise working, but the symmetries of H20 and D20 are such that they each access a subset of the same set of energy levels, one of them can only access even-numbered levels, and the other one only odd-numbered levels!
Where does that get us different freezing temperatures? Well the gaps between energy levels diminish as you go up - so the gap from level 0 to 1 is larger than from 1 to 2 is larger than from 2 to 3 etc... That means the gap from 0 to 2 is just enough larger than the gap from 1 to 3 that it affects how much energy it takes to freeze the different molecules!! So really you'd be aiming to kill Castro with group theory.
>Heavy or semiheavy water is pretty toxic.
When something's less toxic than table salt, I feel "pretty toxic" is an overstatement.
>The basis of cellular energy generation is the proton pump in the mitochondria, which moves hydrogen nuclei around to create a charge gradient. If the hydrogen nuclei have unexpected neutrons, that could jam the pump or change how the gradient works. I'm not entirely able to follow this, but maybe then there is some kind of cellular signaling cascade?
The basic problem with deuterating organisms is that the kinetics of acid-base reactions are significantly different with deuterium (and the thermodynamics are somewhat different - pH of neutral heavy water is 7.44 instead of 7.0 i.e. only 36% as much is dissociated) and screwing up the relative kinetics of things disrupts the functioning of highly-tuned systems like multicellular eukaryotes. Less complex organisms tend to have wider tolerances on these things (partially due to less things to go wrong, partially because the environment of single cells in a multicellular organism is subject to homeostasis and as such adaptability on the cell level isn't normally required), hence why you can grow 100%-deuterated bacteria.
If it came to my attention that Google was genuinely and openly asking about killing Castro in employee interviews, or about doing any other illegal American security state stuff, I'd grow highly concerned and endeavor to stop using Google products as much as a I can (well, in addition to my efforts to already do so, of course).
Why would you not resign from your job at the CIA? Why would you wish to kill Castro? Only an American would not ask these questions.
There are tons of biochemicals besides deuterium where deviating above or below the normal homeostatic levels can kill cells. So when high-D and depleted water both kill cancer cells, not too surprising and I wouldn't count one claim as evidence against the other.
Scott, the link of the supposed cancer review paper link [0] redirects me to [1]: "How E-Business Platform Channels Influence Chinese Auto-parts Wholesale Market?" A curious topic for a pharmaceutical journal, but who am I to judge?
Still, I find the claim of a 50% growth rate reduction in deuterium free water (as opposed to our normal almost deuterium free water) extraordinary. Not quite superluminous neutrino level extraordinary, but still surprising enough that one should get the late James Randi [2] involved or something.
I am not a physician, but from my understanding, cancer cells are not undead Chaos cells thriving on poisons, but basically normal human cells with an unfortunate mutation, running in a nonstandard mode. Generally, I would assume that the environmental requirements for cancer growth are a smallish subset of the environmental requirements of a healthy human. There are certainly things which harm cancer cells disproportionally (e.g. chemo therapy, radiation), but these things also tend to harm healthy tissue to a lesser degree?
[0] https://www.sysrevpharm.org/fulltext/196-1568985381.pdf
[1] https://www.sysrevpharm.org/articles/role-of-ebusiness-in-the-wholesale-market-of-china.pdf
[2] As in the 'memory of water' debacle (https://doi.org/10.1038/333816a0)
This was pretty much exactly the plot of the final episode of the UK series Eleventh Hour starring Patrick Stewart, where scientists were testing water from a spring to see if they could find any contaminants that would explain why local people were being sickened, but all their tests came back negative till he thought to check the density of the water and found it was a secret government heavy water source. https://en.wikipedia.org/wiki/Eleventh_Hour_(British_TV_series)
Has anybody read The Unbearable Lightness of Being? It's pretty good. It's sort of a test kitchen for how different people can answer the questions of existentialism in different ways, and how it feels to live in each different answer. I should reread it sometime.
If you (or the CIA) have a fancy time gizmo, why bother with mundane poisoning? Just use it to accelerate his aging until he dies of natural old age.
Though this is really fascinating, and I've learned a lot more about heavy water than I previously knew!
Anyone here read Medical Nihilism by Jacob Stegenga? I'd be curious to hear Scott's take on it.
Forget Deuterium, it is simpler to remove the salts and ions from the water. I think distilled and/ or deionized water will kill you.
"And there's the oncological argument (that's the St. Anselm thing, right?)"
The heaviest possible water would certainly be made heavier by existing...
I'm a lazy spy: tell the CIA to make me the chemist instead
For whatever it says about me, my answer was to contaminate his water with small amounts of my poop. I don't have cholera or anything, but that has to be at least a little deleterious to health, right? Poop water? ...Google would not hire me with this answer, I think.
Overcharging car batteries would be an easier source than fractional freezing.
https://www.youtube.com/watch?v=bCXB6BdMh9Y
Anyway, why stop at two? Make a nice glass of tritium oxide.
Props for the Milan Kundera-esque title
Scott, in your psychiatric practice have you encountered the use of Austedo (deutetetrabenazine)? A deuterated form of tetrabenazine, it is approved since 2017 for use in tardive dyskinesia and Huntington's disease.
https://www.austedo.com/
There are also deuterated forms of paroxetine, venlafaxine, dextromethorphan, vitamin A, and other drugs, that have been of interest. The latter two are in phase 3.
The advantage of deuterated drugs is an alteration of pharmacokinetics, causing either prolonged or shortened duration of action or reduction of toxic metabolites. These effects are in some cases related to deuterium changing the interaction of the compounds with the active sites of various cytochrome subtypes, especially 2D6 and 3A4.
Well, if light water really is better for us, then we should invest heavily in fusion reactors and use up all of that heavy water!
I'm surprised nobody's raised this nitpick yet, but -- surely you need to start with an amount of water that's much larger than "several thousand times Castro's daily consumption"? (Unless your values of "several" are extremely large, of course.) It seems like you need to end up with at least 100x Castro's daily consumption, and you're halving your amount of water at every freeze/melt iteration.
IIRC the reason ²H is toxic is because proton pumps are evolved to pump ¹H. ²H has twice the mass, so by F = ma you need twice the force. But obviously proton pumps aren't evolved to push with twice the force.
Also, a fun bit of trivia is that D₂O is slightly sweet.
>You would never think to check whether attempts to mine the Martian icecaps for drinkable water will result in dangerous water that could sicken the unfortunate astronauts who drink it (answer: it might! Martian water has five times more deuterium than Earthly water and seems to kill shrimp)
And if there's anything I learned from Doctor Who, it's that drinking Martian water is a baaaaaad idea.
and here is Cody drinking it for your entertainment
https://www.youtube.com/watch?v=MXHVqId0MQc
I read this as an elegant rejoinder to several different points of view regarding Ivermectin expressed in the comments section of the recent "Too Good to Check" post.
You should probably note that the Google brainteaser thing is a myth so people don't get the wrong idea.
> Start with the evolutionary argument. [...] The 10,000 years since the last Ice Age wasn't enough time to re-evolve, so human bodies are probably adapted for slightly lighter water than we get.
What? That's not an evolutionary argument, it's an "I don't believe in evolution" argument.
"Light water halves the growth rate of cancer cells in vitro"
"but some other groups find deuterium causes less cancer, so who knows?"
That effect size seems too big... But anyway, let's take it at face value. With the in vitro part it wouldn't even be that surprising. If our cell chemistry is tuned to the current amount of deuterium in water (ie, pre-ice-age and also current levels), which seems a reasonable prior to me, then any direction of variation, up or down, would harm cancer-cell growth... as well as other-cell growth. The same story as all in-vitro/in-vivo cancer drug studies: Po-210 kills cancer cells real good, for that matter.
Again, half the rate, really? I haven't read the article, but I'd be more enticed to spend my time by a more reasonable claim.
OK but if you make ice cubes out of heavy water, they will sink in your normal-water-based drink, which is a great party trick and totally worth a small probability of dying of cancer or whatever
I have a better memory than most and I did remember deuterium. We can say perhaps it's not the first thought, but better it's there than not.
The takeaway is that we have to remember that people are not the same, and that we, each, ourselves, have to be careful and avoid assuming, and understand that we don't know everything.
This is much like Harvard and the seasons, which was evidence of an appalling lack of curiosity, memory, and grounding in the real world
I looked up the sds of D2O and it said it's nontoxic and didn't include an LD50
I thought of a bunch of other ways to kill Castro, all variously contrived. Various ways to make water toxic. All rely on the sensor just checking for contamination and not other properties
- swap the water for deionized water (deionize it in the kitchen). I know there is concern about drinking deionized water because it can strip minerals and salt from your body. So maybe this will weaken and eventually kill Castro?
- concentrate or remove H groups in the water (somehow). I would imagine you could make an acid or a base this way. So he drinks it and dies horribly?
- 3rd and best option : heat the water in the watercooler to an extremely high temperature, perhaps 600F, but in such a way that it has no impurities or micro structures to form bubbles around so that it cannot boil- no nucleation sites!
Then when Castro is near and the sensor probe/cup/valve, etc opens, there is an introduced nucleation site, then the water can all instantly boil and explode in a massive steam bomb. Bonus points If you also made it a powerful acid so it’s a huge acid cloud doing 10d10 damage to Castro.
This last phenomenon happens sometimes when you microwave water in a really clean container, then drop a spoon in later and it explodes.
DON'Terium
The riddle says "the tests can detect any contaminant at any concentration", so it seems like there's an implicit "except for differing isotopes of water", which overfits the riddle to this particular answer. This seems a little fishy, since semiheavy water would be really easy to detect!
Semiheavy water is about 5% denser than normal water, so even with a fairly imprecise scale, the swap could be detectable, and I have a hard time believing that any battery of tests wouldn't end up computing the density of Castro's water. If I'm the chemist, and I notice that the 100mL samples I'm pulling to check for cyanide or whatever are suddenly weighing 105g, I'm probably asking questions.
Knowledge is exhausting - I sometimes find myself vacillating between Errol Morris’ conviction that there is a real and verifiable “truth” and, on my worst days, a post-modern relativity. The replication crisis and the current Covid wars over every damn thing doesn’t help. I miss simpler times when Encyclopedias Brown and Brittanica provided clear answers.